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There are few side-by-side comparisons on how Kentucky bluegrass (Poa pratensis L.) invasion has affected plant diversity and carbon (C) and nitrogen (N) dynamics. Between 2013 and 2015, four plots (4.9 × 4.9 m) were annually located on a long-term (1916−2016), moderately stocked pasture at the Northern Great Plains Research Laboratory (USDA-ARS) near Mandan, North Dakota. All plots were located on loamy ecological with minimal microsite differences. Each site had areas that were visually observed to have the largest vegetative component dominated by either Kentucky bluegrass (KBG) or dominated by other species (CONT). Two 1/8 m2 quadrats were clipped by species, including detached plant material (litter), within each subplot between mid to late July 2013, 2014, and 2015. This period represents peak biomass production and offers the best opportunity to capture cool- and warm-season perennial species. In 2013, soil samples were taken at depths of 0−5, 5−10, and 10−20 cm within each plot and thatch samples were hand excavated after clipping. Carbon and N were determined on biomass, litter, thatch, and soil samples. KBG plots produced 28% more biomass annually than the CONT plots. In 2014 and 2015, species richness was 0.7−2.1 × greater in the CONT plots. Although N and C concentrations were similar between treatments for aboveground biomass, litter, and thatch when expressed on a g m−2 basis, N was 34% greater for aboveground biomass and 600% greater for litter in KBG plots. Soil organic C and total soil N at 0−5 cm were 26% and 22% greater in KBG plots, respectively. Our findings indicate that KBG plots had less diversity and greater aboveground and belowground N and C than CONT. More follow-on research is needed to understand how C and N stocks and dynamics influence Kentucky bluegrass invasion.

Wildfire is increasing in frequency and size in the western United States with climate change and invasive species such as cheatgrass. This increase is also causing an increase in the need for restoration techniques, especially in low-elevation, arid shrublands. Sagebrush shrublands are home to the threatened Gunnison sage-grouse and can take decades, if not longer, to recover after fire. We investigated management-friendly restoration techniques aimed at increasing sagebrush cover in a sagebrush system important to Gunnison sage-grouse and impacted by fire in western Colorado. We tested several restoration techniques that could be replicated in management actions to mitigate stressors on sagebrush recruitment, specifically herbivory by large ungulates, water limitation, and competition with other plants. We found that sagebrush grew and survived better when planted as transplanted seedlings versus seeds, when planted in areas where herbicide had been applied versus when vegetation was removed by hand tools, and when caged to prevent herbivory than when not caged. Surprisingly, providing supplementary water did not improve sagebrush transplant growth or survival over use of a microsite (small structure made of wood collected from the burn scar). Constructed microsites were meant to provide protection from wind, retain moisture, and provide shade. Overall, our results indicate that if sagebrush seedlings are provided shelter and structure, then survival can approach natural (not planted) rates and sagebrush can be successfully established in low-elevation sites.

The divergent gap characteristics and spatial patterns of canopy gaps created by natural or artificial disturbances can exert a dominant influence on forest structure and composition. However, little research has been conducted on the effects of ice storm damage on canopy gaps in subtropical mature forests of South China. In this study, one semi-natural site was dominated by a broad-leaf forest and two managed sites were representative of plantations with coniferous forests. Based on airborne laser scanning data and field evidence across sites, statistical analyses were used to examine gap characteristics following ice storms of moderate severity. Generalized Ripley’s K-function analysis was applied to test gap spatial patterns at a range of scales, and spatial point pattern analysis was used to quantitate the relative importance of specific influences on patterns of gap occurrence. The results revealed that the average gap size was 75.7 m2 and that 12.2 gaps occurred per hectare. Most gaps were single-tree fall events. In addition to more gaps, the mean gap size was smaller and the shape was more complex in the semi-natural site than in two managed sites. Large differences in gap characteristics were observed among snapped, uprooted, snag, and artificial gap damage types. Gaps generally showed a clustered distribution at large scales (e.g. 70m), whereas spatial patterns varied with gap damage types at different sites. The occurrence of gaps was strongly related to slope and topographic position at the semi-natural site, whereas slope, stem density, and human accessibility (proximity to pathways) were the most important factors affecting gap occurrence at the managed sites. We suggest that gap-based silvicultural treatments and natural disturbances regimes conjoin, highlighting interactions with other factors such as microsite conditions, non-tree vegetation and more.

Post‐fire restoration of foundation plant species, particularly non‐sprouting shrubs, is critically needed in arid and semi‐arid rangeland, but is hampered by low success. Expensive and labor‐intensive methods, including planting seedlings, can improve restoration success. Prioritizing where these more intensive methods are applied may improve restoration efficiency. Shrubs in arid and semi‐arid environments can create resource islands under their canopies that may remain after fire. Seedlings planted post‐fire in former canopy and between canopies (interspace) may have different survival and growth. We compared planting Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young) seedlings post‐fire in former sagebrush canopy and interspace microsites at five locations. Four growing seasons after planting, seedling survival was 46 and 7% in canopy and interspace microsites, respectively. Sagebrush cover was 5.8 times greater in canopy compared to interspace microsites. Sagebrush survival and cover were likely greater because of less competition from herbaceous vegetation as well as benefiting from resource island effects in canopy microsites. Initially, post‐fire abundance of exotic annual grasses was less in canopy microsites, but by the third year post‐fire it was substantially greater in canopy microsites, indicating that resource availability to seedlings was greater, at least initially, in canopy microsites. These results suggest microsites with greater likelihood of success should be identified and then utilized to improve restoration success and efficiency. This is important as the need for restoration greatly exceeds resources available for restoration.

Forest restoration is most efficient if it can take advantage of facilitative interactions between established vegetation and planted trees. However, positive and negative interactions have been identified in a number of plant communities. After centuries of anthropogenic fires, forest recovery has been extremely slow in southern bog forests previously dominated by the slow‐growing and vulnerable conifer Pilgerodendron uviferum on Chiloe Island, Chile. Today, the landscape is dominated by secondary shrublands with scattered patches of Sphagnum moss and limited natural tree regeneration. We hypothesized that the retention of secondary shrubs facilitates the early performance of P. uviferum restoration plantings by providing better microsite conditions. To test this hypothesis, we compared the response of seedlings planted on sites prepared at two levels of intervention: after shrubs had been removed or where shrubs were retained. Shrub retention showed a nurse‐plant effect on P. uviferum seedlings 4 years after planting, which resulted in reduced physiological stress (measured as Fv/Fm) for seedlings, as well as reduced browsing. Consequently, the seedlings growing in areas with shrub retention had larger height increment and higher vitality than those in areas where shrubs had been removed. Thus, the more open micro‐site conditions created by shrub removal resulted in generally poorer seedling performance, although seedling mortality—which was low overall (approximately 2–4%)—showed no significant difference between the two levels of intervention. These findings have direct implications for the restoration of slow‐growing conifers that can tolerate extreme wet conditions in highly degraded forests.

Seedling recruitment following a masting event, where more fruits are produced in synchrony and intermittently compared with other species, plays a crucial role in determining species diversity and community structure. Such seedling recruitment can be superabundant, but followed by high mortality shortly thereafter. Differences in biotic factors such as seedling characteristics, competition, and herbivory, and microsite‐specific abiotic factors could determine seedling fate in space and time.In a subtropical forest in south China, for 2 years using censuses conducted every 1–2 months, we monitored 40 seed traps and 120, 1 m2 quadrats in five 1‐ha plots located from 1,400 to 1,850 m asl for the masting maple species, Acer campbellii subsp. sinense (Pax) P.C.DeJong. We measured biotic—conspecific and heterospecific seedling density, species richness, herbivory, seedling height, and leaf number—and abiotic—canopy openness, slope, and aspect—factors to assess drivers of seedling survival and evaluated A. campbellii subsp. sinense presence in the soil seed bank (SSB).The masting seed dispersal peak and seedling emergence peak occurred between October 2017 and January 2018, and May 2018, respectively. Of 688 selected seedlings, mortality was 92.7% within one year. No seeds were observed in the SSB. Seedling height and leaf number positively affected seedling survival, while seed placement as measured by aspect also showed effects on survival. Conspecific and heterospecific density and herbivory did not show any clear effect. Higher probabilities of seedling survival were found in areas with larger canopy openness (≥12% canopy gap size) and in steeper microsites (≥35°). Synthesis. Masting is mainly studied as a population‐level phenomenon from the fruiting tree perspective. Our study of individual seedling fate revealed that intrinsic biotic factors and seed placement were key drivers of survival. Although biotic determinants such as competition from conspecifics or heterospecifics or herbivory did not determine survival, their ubiquitous presence may be an underlying equalizer in community dynamics where seedlings that overcome biotic pressures, if placed at the right microsite, are at better odds at being recruited to the next life history stages., We monitored seed rain, soil seed bank, and seedling recruitment and survival for the masting maple species, Acer campbellii subsp., in a subtropical forest in South China. The masting seed dispersal peak and seedling emergence peak occurred between October 2017 and January 2018, and May 2018, respectively. Seedling mortality was 92.7% within 1 year, and we found no seeds in the SSB. Our study of individual seedling fate revealed that intrinsic biotic factors—seedling height and leaf number—and seed placement—aspect—were key drivers of survival.

Within plant communities, niche‐based species sorting can occur among distinct soil patches (microsites), increasing coexistence and diversity. Microsite edges (microedges) may also offer additional niche space. Therefore, in recently abandoned croplands, which often have uniform soils caused by a legacy of tillage (soil homogenization), the plant species diversity of future restoration efforts may be reduced. We conducted an experiment during the early establishment phase (3 years) of a tallgrass prairie restoration on former cropland to determine if soil homogenization decreases species diversity and alters community composition, and if microedges offer additional niche space. Heterogeneous plots with sand‐ or woodchip‐enriched patches were compared to plots made up of the same components, but distributed homogeneously, and pits and mounds were compared to flat topsoil. Homogenization decreased diversity in flat topsoil plots relative to pit plots and increased diversity in woodchip plots. In both cases, the treatments with the lowest canopy cover and greatest plant density had the greatest diversity. Sand and topographic homogenization decreased diversity, but when a drought occurred in year two, the effect was suppressed in the sand treatment and magnified in the pit plots. Microedges had properties unique from adjacent patches. Overall, variability in heterogeneity–diversity relationships was affected by interactions with plant growth patterns and environmental conditions. Our results indicate that while the addition of contrasting soil microsites has the potential to promote increased diversity in grassland restoration on former cropland, the patch components and design must be optimized to achieve this management goal.

Chinese pine (Pinus tabulaeformis Carr.) is a widely distributed moderately shade-tolerant tree species with important economic and ecological value in northern China. The productivity of the plantations established by the government in the 1970s has apparently begun to decline. Therefore, the identification of silviculture measures that can feasibly and reasonably balance timber production and sustainable forest management is of interest to many operators and researchers. The main purpose of our study was to understand whether the height growth of trees regenerating under the canopy would positively respond to thinning and provide sufficient high-quality regenerating trees for the successful transformation to uneven-aged forests. Four different thinning intensity treatments were implemented in a 40-year-old plantation based on the number of trees that were cut down using the thinning-from-below approach: 0.0% (unmanaged), 20.0–21.0% (weak thinning), 30.0–31.0% (moderate thinning), and 40.0–41.0% (strong thinning). After five years of thinning, the differences in growth among the different thinning intensities were compared using nonparametric statistical methods. Additionally, the height growth rates of regenerating trees over the past five years were predicted using a linear mixed-effects model that included variables related to stand characteristics, soil physiochemical properties and measurements of individual regenerating trees. The results showed that thinning could significantly promote the height growth of regenerating trees in comparison to the growth in unmanaged plots. Significant differences were found among thinning intensities in terms of growth, excluding ground diameter, with the maximum and minimum values in the strong thinning and unmanaged plots, respectively. However, the models never explained more than 50% of the variation regardless of whether the plot level or the individual level was considered, although they included the majority of the evaluated variables. In conclusion, strong thinning is a potentially feasible silvicultural method for uneven-aged Chinese pine plantations in northern China. Some factors that are important in terms of the growth of regenerating trees but were not tested in our study, such as competition, light intensity and distribution, and microsite environment, are recommended to be considered in future research to improve the explanatory power of the model. Moreover, based on our results and to supplement thinning, the gap expansion harvesting system should be carried out in gaps opened by thinning to not only maintain stand stability but also facilitate the growth of regenerating trees into the canopy for canopy recruitment.

Small forest fragments are often the most abundant type of semi-natural habitat in intensive agricultural landscapes. Wild pollinators can use these forest patches as nesting or foraging habitat. However, the importance of small forest fragments as pollinator habitat has been neglected so far. We evaluated the role of these forest patches as pollinator habitat, focusing on the effect of nesting and foraging resources, both at a local and at a landscape scale. Pollinators were sampled with pan traps in 78 forest patches, spread over five study regions in Northwestern Europe. We evaluated effect of forest and landscape characteristics on bee and hoverfly species richness, diversity and activity-abundance. We showed that the bee community is influenced by both microsite conditions and landscape characteristics. Species richness and activity-abundance were higher when suitable nesting resources, such as sloped terrain and bare soil were available. This suggests that forest edges are important in providing nesting sites, but that most species forage in different habitats. Hoverfly species richness was higher in old forest fragments. This relation was mainly caused by the presence of forest specialist hoverflies in old forest fragments. Small forest fragments in agricultural landscapes can harbour a diverse pollinator community. Increasing the amount of nesting habitat, such as bare soil and sloped terrains is expected to have beneficial effects on the bee community, whereas older forest fragments should be conserved to sustain a rich hoverfly community.

In Low Arctic tundra, thermal erosion of ice‐rich permafrost soils (thermokarst) has increased in frequency since the 1980s. Retrogressive thaw slumps (RTS) are thermokarst disturbances forming large open depressions on hillslopes through soil wasting and vegetation displacement. Tall (>0.5 m) deciduous shrubs have been observed in RTS a decade after disturbance. RTS may provide conditions suitable for seedling recruitment, which may contribute to Arctic shrub expansion. We quantified in situ seedling abundance, and size and viability of soil seedbanks in greenhouse trials for two RTS chronosequences near lakes on Alaska's North Slope. We hypothesized recent RTS provide microsites for greater recruitment than mature RTS or undisturbed tundra. We also hypothesized soil seedbanks demonstrate quantity–quality trade‐offs; younger seedbanks contain smaller numbers of mostly viable seed that decrease in viability as seed accumulates over time. We found five times as many seedlings in younger RTS as in older RTS, including birch and willow, and no seedlings in undisturbed tundra. Higher seedling counts were associated with bare soil, warmer soils, higher soil available nitrogen, and less plant cover. Seedbank viability was unrelated to size. Older seedbanks were larger at one chronosequence, with no difference in percent germination. At the other chronosequence, germination was lower from older seedbanks but seedbank size was not different. Seedbank germination was positively associated with in situ seedling abundance at one RTS chronosequence, suggesting postdisturbance revegetation from seedbanks. Thermal erosion may be important for recruitment in tundra by providing bare microsites that are warmer, more nutrient‐rich, and less vegetated than in undisturbed ground. Differences between two chronosequences in seedbank size, viability, and species composition suggest disturbance interacts with local conditions to form seedbanks. RTS may act as seedling nurseries to benefit many Arctic species as climate changes, particularly those that do not produce persistent seed.

Reforestation in the tropics mitigates the negative effects of climate change by sequestering carbon in biomass. However, tree growth is limited by nutrient availability in many tropical regions. A clear understanding of nutrient constraints and topography on growth of native timber species is thus essential to improve both the economic return on reforestation and the ecosystem services in tropical degraded lands. To address this, we use 7-year growth data from a 75-ha reforestation experiment in central Panama to test a modeling approach to predict growth of these species. The experiment includes five valuable timber species in 21 treatments, including monocultures and mixtures. We first fit a non-linear growth model as a function of tree age, then expand the former model parameters as a function of variables related to species mixture and micro-site soil conditions. Finally, we built a final model for each species to predict growth along three axes: nutrient availability, slope and species mixture. The models successfully identified how variation in growth was related to micro-site conditions and the species mixture. Although all species were long-lived pioneers, most were overall more sensitive to nutrient availability and between-trees interactions than to slope. However, the fastest growing species on average was more sensitive to slope than the other species and less sensitive to nutrient availability, showing better performance than the other species even under adverse conditions. Our models aid identification of species with the best growth potential to use in reforestation on infertile soils, leading to a better species selection according to site conditions.

The increasing frequency and severity of fire and drought events have negatively impacted the capacity and success of reforestation efforts in many dry, western U.S. forests. Challenges to reforestation include the cost and safety concerns of replanting large areas of standing dead trees, and high seedling and sapling mortality rates due to water stress, competing vegetation, and repeat fires that burn young plantations. Standard reforestation practices have emphasized establishing dense conifer cover with gridded planting, sometimes called ‘pines in lines’ followed by shrub control and pre-commercial thinning. Resources for such intensive management are increasingly limited, reducing the capacity for young plantations to develop early resilience to fire and drought. This paper summarizes recent research on the conditions under which current standard reforestation practices in the western U.S. may need adjustment, and suggests how these practices might be modified to improve their success. In particular we examine where and when plantations with regular tree spacing elevate the risk of future mortality, and how planting density, spatial arrangement, and species composition might be modified to increase seedling and sapling survival through recurring drought and fire events. Within large areas of contiguous mortality, we suggest a “three zone” approach to reforestation following a major disturbance that includes; (a) working with natural recruitment within a peripheral zone near live tree seed sources; (b) in a second zone, beyond effective seed dispersal range but in accessible areas, planting a combination of clustered and regularly spaced seedlings that varies with microsite water availability and potential fire behavior; and (c) a final zone defined by remote, steep terrain that in practice limits reforestation efforts to the establishment of founder stands. We also emphasize the early use of prescribed fire to build resilience in developing stands subject to increasingly common wildfires and drought events. Finally, we highlight limits to our current understanding of how young stands may respond and develop under these proposed planting and silvicultural practices, and identify areas where new research could help refine them.

Proper management of woods infested by bark beetle – clearing infested trees to prevent spread of bark beetle, or leaving them to preserve biodiversity – is a hotly debated topic. Differences in temperature regime between differentially managed areas are often-used arguments in these discussions. Results from the field measurements are confusing. Therefore, here we review previous studies and report our results of using thermal sensors in the field to determine the factors that might affect the differences in temperature reported in previous papers. Our results indicate that the variability recorded in one particular habitat, dry forest, is associated with the specific characteristics of the locality of each microsite/sensor. We conclude that it is important to consider not only the temperatures recorded but also describe microsites in detail in terms of vegetation structure, sunshine or numbers of trees per unit area.

The effective sustainable management of introduced woody species requires understanding of the mechanisms which affect successful colonization in different forest habitats. We studied the spontaneous spread of the alien species – Northern red oak (Quercus rubra) in the Scots pine (Pinus sylvestris) forest located in Poland. We analysed the impacts of seed source distance, presence of and distance from linear structures (public and forest roads) in the landscape, as well as microhabitat diversity, on the distribution of juvenile red oaks. We also studied the effects of types of acorn deposition sites (under shrubs, within clumps of Vaccinium myrtillus, in the open), and ways of seed burial (in moss wefts, in rodent corridors) by animal seed hoarders on seed germination and seedling growth. Field data were collected in six transect lines divided into 3300 plots (1 m2 each). We found that Q. rubra efficiently colonizes Scots pine monoculture. Results of spatially explicit hierarchical generalized linear models showed that distance from acorn sources and occurrence of sparse shrub layers are the most important predictors of Q. rubra ecological success, defined as establishment of juvenile specimens. The presence of roads – potential migration corridors for avian and mammalian acorn consumers/dispersers – favoured non-random red oak spread. The “nurse effect” of native understory components on red oak seed germination and seedling growth was indicated by higher numbers of juvenile specimens as well as by higher proportions of germinated seeds noted under shrubs than in open areas (without shrubs) or within clumps of V. myrtillus. All red oaks developed from seeds buried in compact moss wefts or in spacious caches and corridors created by rodents in the moss layer, which indicated a positive “burial effect”. We conclude that microhabitats make the Scots pine forests very suitable for Q. rubra invasion. Because of the wide distribution of numerous red oak stands in European temperate forests and the presence of numerous oak seed dispersers, the continuous colonization of widespread Scots pine monocultures by Q. rubra must be expected.

Timber harvests may facilitate ant invasions of forested landscapes, fostering interactions between non-native and native ants. Harvests that include removal of low-value woody biomass as forest bioenergy feedstock may reduce residual coarse woody debris, thereby altering food and cover resources for ant species. We manipulated: (1) volume and distribution of coarse woody debris in stand-scale treatments ranging from intensive coarse woody debris removal to no coarse woody debris removal; and (2) coarse woody debris availability at microsite locations within stand-scale treatments, including piles of hardwood stems, piles of conifer stems, and no pile locations in North Carolina, USA and windrows (i.e., long, linear piles of harvest residues) and no windrows in Georgia, USA, in recently clearcut pine plantations (n = 4 per state). We captured ants in regenerating stands and tested treatment- and location-level effects on non-native and native ant relative abundances. Invasive ants represented 19% of ant taxa richness, but comprised 94% of total ant captures. Red imported fire ant (Solenopsis invicta Buren, hereafter “RIFA”) dominated the ant community in young plantations. RIFA avoided windrows, but its relative abundance did not differ among stand-scale treatments. Coarse woody debris retention in stand-scale treatments and at microsite locations favored non-RIFA ants, including Asian needle ant (Brachyponera chinensis Emery) and several native ant species. Dual invasions of RIFA and Asian needle ant in young plantations of the eastern United States may commonly occur because the two species may not compete for resources on the forest floor. Reduction of coarse woody debris via intensified woody biomass harvesting may negatively affect non-RIFA ant species and promote RIFA colonization, thereby indirectly increasing deleterious effects of RIFA on other wildlife.

In mountain ecosystems, plants are sensitive to climate changes, and an entire range of species distribution can be observed in a small area. Therefore, mountains are of great interest for climate-growth relationship analysis. In this study, the Siberian spruce’s (Picea obovata Ledeb.) radial growth and its climatic response were investigated in the Western Sayan Mountains, near the Sayano-Shushenskoe Reservoir. Sampling was performed at three sites along an elevational gradient: at the lower border of the species range, in the middle, and at the treeline. Divergence of growth trends between individual trees was observed at each site, with microsite landscape-soil conditions as the most probable driver of this phenomenon. Cluster analysis of individual tree-ring width series based on inter-serial correlation was carried out, resulting in two sub-set chronologies being developed for each site. These chronologies appear to have substantial differences in their climatic responses, mainly during the cold season. This response was not constant due to regional climatic change and the local influence of the nearby Sayano-Shushenskoe Reservoir. The main response of spruce to growing season conditions has a typical elevational pattern expected in mountains: impact of temperature shifts with elevation from positive to negative, and impact of precipitation shifts in the opposite direction. Chronologies of trees, growing under more severe micro-conditions, are very sensitive to temperature during September-April and to precipitation during October-December, and they record both inter-annual and long-term climatic variation. Consequently, it would be interesting to test if they indicate the Siberian High anticyclone, which is the main driver of these climatic factors.

Prescribed burnings have been generally used for fuel reduction in Mediterranean forest ecosystems and in fire-prone areas. It is usually held that prescribed fire may alter microsite conditions, but very little is known about the impact of prescribed burning on Mediterranean pine species’ natural regeneration. In this study, we aim to know the effect of prescribed burning, soil preparation (scalping) and seed protection on the initial recruitment of Spanish black pine (Pinus nigra Arn. ssp salzmannii), maritime pine (Pinus pinaster Ait.) and Aleppo pine (Pinus halepensis M.) in the Cuenca Mountains (central-eastern Spain) after a 1 year of experiments. Our results indicated that the seed emergence rate was higher in the scalped plots for Maritime pine and Aleppo pine. In the case of Spanish black pine, differences comparing treatments for the emergence rate were weaker. Scalped and protected plots showed the highest seedling survival rate for Aleppo pine and Spanish black pine whereas protected and control plots perform better in the case of Maritime pine. Thus, seed protection is a crucial factor for ensuring seedling survival after the first growing season. By considering our results about early pine species recruitment, prescribed burning must be carefully planned when the natural regeneration of Spanish black pine, maritime pine and Aleppo pine is the aim.

Burrowing mammals are often considered to be ecosystem engineers as burrowing disturbs the soil, thereby potentially changing resource availability and affecting habitat conditions for other species. After their excavation, burrows may strongly impact local plant communities through several mechanisms, including resource trapping, altered chemical and physical soil properties, and amelioration of microclimatic conditions. We studied ecosystem engineering by aardvark (Orycteropus afer) burrowing by comparing soil and vegetation characteristics between three microsites (burrow entrances, excavated soil mounds and adjacent control sites). We were able to identify several engineering effects and distinguish between potential mechanisms. Burrow soils were cooler, drier and less compact than the other microsites, with all three microsites representing unique combinations of abiotic conditions. Mean species richness was higher at older burrows than mounds and non-burrowed controls, despite burrows having a smaller seedbank and not differing in soil fertility from mounds and control sites. However, the opposite was observed at fresh burrows and mounds, where control plots contained more species on average than the other two types of microsites. Burrow age and microsite type also affected species composition, although only a small proportion of species were significantly associated with specific microsites and just two species were limited to a single microsite type. We suggest that trampling and the physical digging action at burrow entrances, and burial by deposited soil at mounds, prevents the establishment of many plant species at active burrows. However, once abandoned, burrow entrances provide good physical conditions for seedling survival, allowing the establishment of more species. Therefore, as suggested previously for other ecosystem engineers, it is important to explicitly consider the age and degradation processes of engineered structures. In addition, our results highlight biologically-important differences in engineering impacts between burrow entrances, where soil is removed, and mounds, where soil is deposited. Such microscale differences are important to consider when examining bioturbation or, more generally, ecosystem engineering.

On deforested or degraded land, planting mixtures of native forest tree species facilitates establishment of incoming tree seedling species (species recruitment) by rapidly re-establishing canopy cover. However, delayed colonization of plantations by large-seeded, zoochorous (LSZ) tree species can affect the species composition, structure, and function of the developing forest. The objective of this study was to investigate whether microsites limit establishment (germination and early seedling survival) of LSZ tree species in three 13-year-old, seasonally dry, tropical forest restoration plantations in northern Thailand. We conducted a seed sowing experiment that combined five LSZ tree species with four microsite treatments in a split-plot design. All five tree species were previously absent from the understory of the plantations, despite seed sources being present in nearby natural forest. The four treatments simulated potential microsites that naturally-dispersed seeds may encounter. They included seed deposition on the surface of soil and on leaf litter, as well as seed burial beneath soil and beneath leaf litter. We fenced the experimental areas to prevent seed predation and focus on the environmental effects of microsites on the different stages of seedling establishment. Following seed sowing, we measured germination and seedling survival, mean height, and stem diameter over 26 months. The microsites treatments did not significantly affect germination and seedling survival, providing strong evidence that establishment of the tested species was not limited by the applied microsite environments. Furthermore, although there were significant differences in germination and survival among species, relatively high overall germination (37%) and 26-month seedling survival (58.5%), irrespective of microsite treatment, suggested that environmental conditions in the 13-year-old plantations generally met the requirements for germination and early seedling establishment. Microsite treatments also did not correlate with seedling height or stem diameter at 20 months, suggesting that initial germination microsites have no effect on seedling growth and robustness. Taken together, the results of this investigation support the hypothesis that seedlings of LSZ tree species are slow to colonize tropical forest restoration plantations because of seed limitations resulting from inadequate seed dispersal or low seed availability. The successful establishment of LSZ seedlings from sown seeds in this experiment suggests that direct seeding beneath the canopy of restoration plantations may be an effective way to offset seed dispersal limitations in restoration plantations. Furthermore, the absence of microsite treatment effects suggests broadcast sowing of seeds may be a simple way to recolonize closed-canopy restoration plantations with LSZ tree species.

Most previous studies of resting habitat for fishers (Pekania pennanti) in the Pacific coastal region of the western United States and Canada were focused on habitat conditions within rest sites (typically ≤0.5 ha), which include the rest structure (e.g., live tree, snag, log) at its center. Studies of selection for rest structures were sparse and compared characteristics of rest structures to those occurring within rest sites; none investigated selection by sampling resource availability throughout the study area. In addition, limited data were available on the use of rest microsites (e.g., mistletoe brooms, platform branches, cavities) by fishers, and no studies have quantified their availability. To better inform forest management activities designed to improve resting habitat for fishers, we documented use of rest structures and microsites throughout the year by 12 female and 7 male fishers on the west slope of the Cascade Range in southern Oregon, USA from 1995 to 2001, systematically sampled the availability of rest structures and microsites, and used logistic regression modeling to investigate selection of rest structures. Fishers primarily used live trees (65%), snags (14%), and logs (16%) for resting; in all 3 resulting models, the characteristic that best distinguished used from available rest structures was the presence of a suitable rest microsite: mistletoe broom or cavity in live trees, cavity in snags, and hollow end in logs. Only the snag and log models included covariates associated with tree size, likely reflecting the need for enclosed rest microsites (cavities, hollow ends) to be large enough to contain an adult fisher. We then used our availability data to model the ecological characteristics associated with mistletoe brooms in live trees, cavities in snags, and hollow ends in logs. Whether a tree was a hemlock (Tsuga spp.) had the greatest effect on the presence of suitable mistletoe broom microsites, but the most important characteristics of snags with cavities and logs with hollow ends were being in moderate stages of decay and relatively large in diameter at breast height (snags) or diameter 3 m from the large end (logs). Forest structures containing suitable rest microsites for fishers were uncommon in our study and may represent a limited resource. Accordingly, we recommend that management of resting habitat for fishers be focused on retaining relatively large structures that already contain suitable rest microsites, rather than simply retaining the largest available structures. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Revegetation of exotic annual grass − invaded rangeland with preemergent herbicides is challenging because seeding is delayed until herbicide toxicity has diminished, but at this time, exotic annuals can be reinvading. Incorporating seeds into activated carbon pellets may allow seeding to occur at the same time as exotic annuals are controlled with a preemergent herbicide because activated carbon can neutralize the herbicide in the microsite around seeds. I evaluated using activated carbon pellets with six species seeded at the same time imazapic was applied to control exotic annual grasses at two sites. Two of the six species establish enough at one site to evaluate the effects of pellets. These two bunchgrasses had greater density and growth (height, leaf length, number of stems and leaves) when incorporated into activated carbon pellets compared with seeded as bare seed. This demonstrates activated carbon pellets can be used to protect seeded bunchgrasses from imazapic applied to control exotic annuals.

Many studies demonstrated the importance of facilitative effect by nurse plant on seedling establishment. Few studies evaluated the negative effects of consumers on plant establishment under nurse plants by dealing with them during multiple demographic processes. We investigated the balance between the facilitative effect and negative effects of consumers during multiple demographic processes in Malawi in southeastern Africa. We chose Ficus natalensis as a nurse plant and compared it with three other microsites in tropical woodlands: Brachystegia floribunda (a dominant woodland species), Uapaca kirkiana (a woodland species), and a treeless site. We quantified the seed rain, postdispersal seed predation, germination, and seedling survival of Syzygium guineense ssp. afromontanum (a common forest species). Within each microsite, we quantified the overall probability of recruitment. We also measured seedling abundance of S. guineense ssp. afromontanum. We found that Ficus natalensis exerted both positive and negative impacts on the establishment of S. guineense ssp. afromontanum. Ficus natalensis facilitated seed deposition, seed germination, and seedling survival. On the other hand, seed removal at postdispersal stage was highest under F. natalensis. Interestingly, B. floribunda also had positive effects on germination and seedling survival, but not on seed deposition. When we excluded the seed arrival stage from our estimation of the recruitment probability, the highest value was found under B. floribunda, not under F. natalensis. When we included the seed arrival stage, however, the order of recruitment probability between F. natalensis and B. floribunda was reversed. The probability was one order of magnitude higher under F. natalensis than under B. floribunda. Our estimation of the probability which included the seed arrival stage was consistent with natural patterns of S. guineense ssp. afromontanum establishment. Despite the presence of opposite effects, the net effects of F. natalensis on S. guineense ssp. afromontanum recruitment in tropical woodlands can be positive.

Restoration projects are usually assessed using short-term measures, leaving a dearth of detailed long-term successional data from restoration sites. This study examines the effects of microsite variation and restoration treatment on successional trajectories and three-to-eight-year restoration outcomes in upland prairies in Oregon’s Willamette Valley. I sought first to determine whether different upland prairie restoration units show similar successional trajectories, second, to identify which exotic species have persistent effects on restoration outcomes, and finally, to determine how variation in restoration treatment, topography, and aspect affect restoration outcomes. Permanent plots in two replicate units showed very similar trends over five years, and similar outcomes to restoration units at a second upland site. Exotic annuals were short-lived and did not prevent establishment of the primary planted species, the native grass Festuca roemeri (Roemer’s fescue). Festuca roemeri established well mid-slope and in valleys but not on ridges. Where native forbs were seeded, forb abundance was higher in plots with less F. roemeri cover, suggesting that it is not cost-effective to seed forbs along with high rates of native grasses. However, seeding F. roemeri at high rates may be an effective strategy when forb seed is not available. A suite of exotic perennial forbs, including Hypochaeris radicata (false dandelion), contributed to diversity and provided nectar resources for pollinators without becoming dominant, while other exotic forbs such as Cirsium spp. (thistle) and Dipsacus fullonum (Fuller’s teasel) required active management.

Among recovery strategies for secondary and degraded tropical forests, the introduction of tree species is one of the most commonly used. This is achieved particularly through the planting of nursery-grown seedlings (i.e. seedling introduction). Another less common technique, but one that could prove efficient, is sowing seeds (i.e. direct seeding) in the forest floor. However, very few comparisons have been made in the literature in terms of the ecological and economic costs and benefits between these two techniques. This study presents a cost-efficiency analysis of the introduction of seedlings and seeds of Oreomunnea mexicana (a threatened species in Mexico) in a secondary Tropical Montane Cloud Forest in central Veracruz, evaluating (1) the performance of the seedlings derived from each of the two practices, (2) the relationship of their performance with the environmental variables at the microsite level, and (3) the ecological and economic cost-efficiency of each practice. At the end of the experiment, survival was higher in the nursery-grown than in the direct-seeded seedlings (97% vs. 22%, respectively); however, the relative growth rate in height was lower for the planted than the emerged seedlings (0.02 ± 0.002 vs. 0.03 ± 0.002 cm cm−1 month−1). Relative growth rate in diameter was similar in seedlings introduced by either technique. No predation of seeds or seedlings was registered. The cost-efficiency analysis revealed that, considering the costs of production and plantation, introducing seedlings was almost two times more expensive compared to direct seeding. Results suggest that recovery of this species is feasible with combined practices depending upon the life stage of the plant and the conditions of the microsite. Improvements to these techniques, such as protection of the seed plumules, could confer even greater ecological and economic advantages for the introduction of O. mexicana in tropical secondary forests.

Natural regeneration of European beech (Fagus sylvatica) and Norway spruce (Picea abies) plays a crucial role in the future of many European mountain forests. It is affected by various soil and stand-related factors whose relative importance, especially in mixed stands, is still not known. In this study, we assessed the importance of stand composition, soil wetness, disturbances and different microsites and seedbeds for regeneration of beech and spruce in a mixed old-growth mountain forest. We also focused on how the effects of these factors change as regeneration gets older. We sampled all regeneration in 563 plots from different microsite types (deadwood, intact soil, treethrow pits and mounds), distinguishing three seedbeds (mosses, beech litter, bare substrate) for seedlings. We used soil survey and tree census data with generalized linear mixed models and variance partitioning to identify the main factors driving tree regeneration and their relative importance. Although beech was slightly less abundant in the canopy than spruce, it strongly outnumbered spruce in regeneration. Beech regeneration showed an affinity for beech litter-rich microsites and drier soils, while spruce was more common on deadwood and moister soils and its response to the seedbed was microsite-specific. The regeneration of both species was positively related to the proportion of their own species in the canopy, but more so in seedlings than in older regeneration cohorts, where soil wetness was more important. The overall pattern of tree regeneration thus resulted from a complex interplay between site conditions and their alterations by current and former generations of canopy trees through the creation of new microsites (deadwood, uprooting mounds) or litter production. Where beech regeneration is not suppressed by excess soil wetness, it is much more successful than spruce due to its shade tolerance and ability to be established in the beech litter that dominates the forest floor. On the other hand, spruce regeneration is mostly restricted to elevated microsites with lower litter accumulation, such as deadwood and treethrow mounds. Our results indicate that both species exhibit an ability to modify their environment in favor of their own regeneration, but under current conditions, beech is more successful than spruce and can be expected to increase its dominance in the future.

It has been firmly established that oak regeneration benefits from prescribed burning and reduced competition with fire-intolerant tree species. Despite recommendations for research on the role of the microsite environment for oak regeneration, very little is known about the interacting effects of fire, soil, and surrounding plant community on oak establishment. We collected undisturbed and burned soil in the aftermath of a wildfire in Great Smoky Mountains National Park and used amplicon sequencing to identify differences in composition of bacterial and fungal communities between unburned and burned soils. To assess the effects of plant community, fire-induced shifts in soil microbial communities, and their interaction we conducted a glasshouse experiment and grew Quercus velutina seedlings in factorial treatments of plant neighbor (oak vs. pine seedling) and soil burn status (unburned vs. burned soil). Fire reduced the diversity of plant pathogenic and saprotrophic fungi and reduced the relative abundance of plant pathogenic fungi. Fire did not affect soil bacterial communities. Shifts in soil fungal community composition enhanced oak seedling root growth, but the effect of the soil microbiome was mediated by plant neighbor interactions. Seedling root growth was negatively correlated with diversity of pathogenic fungi. Root growth was enhanced in burned soil relative to unburned soil, but only when growing with a pine seedling neighbor as opposed to an oak seedling neighbor. Results from this study show that interactions between soil microbes and nearby plants can in part mediate oak seedling growth. As such, nuanced decisions that consider the ecological interactions of the microsite environment are needed to achieve desired outcomes for oak regeneration.

Throughout much of its range, northern white-cedar (Thuja occidentalis L., hereafter cedar) has experienced a bottleneck in recruitment: cedar seedlings are often abundant in these stands, particularly in lowland settings, yet cedar sapling densities are quite low, leading to concerns that cedar canopy trees are not being replaced. Several barriers to cedar recruitment have been suggested; however, findings from previous studies have been inconsistent with regard to limiting factors. Our objective was to characterize the microsite conditions associated with the establishment of cedar seedlings and saplings. We achieved this objective by mapping the location of seedlings, saplings, and overstory trees in 15 lowland cedar stands at five sites in Maine, USA, and examining the fine-scale site conditions (microtopographic features, canopy openness) in which cedar seedlings and saplings occurred. In particular, we recorded the occurrence of seedlings and saplings on microtopographic mounds, pits (small depressions), and flats (transitional features between mounds and pits). Substrate moisture content in these features decreased in the order pits > flats > mounds. Contingency-table results demonstrated that live cedar seedlings, and to a slightly lesser extent saplings, were found more often than expected by chance on mounds, and less often on flats and pits. Logistic regressions using status (live vs. dead) as the response variable generally supported these findings: dead seedlings were strongly associated with pits; however, the occurrence of live seedlings and saplings did not differ between flats and mounds. A companion planted-seedling experiment strongly supported these results, showing that after two growing seasons, survival was significantly lower in pits (12%) when compared to flats and mounds, which had similarly high levels of survival (62 and 80% respectively). Logistic regressions also showed live seedlings and saplings to be prevalent under more open canopy conditions (mean 19%, range 6 to 42% openness); though results from a planted-seedling experiment suggested that greater canopy openness (mean 32%, range 13 to 57%) was detrimental to survival. Regressions also showed that browsed seedlings were more likely to be found dead. These findings point to management prescriptions that maintain microtopographic diversity, create moderately open canopy conditions, and protect stands from browsing to promote viable cedar populations in these ecologically and economically important forests.

Natural objects that buffer climate extremes and potentially function as regeneration niches are ubiquitous in dry miombo woodlands, yet few studies have explored their effects on early stages of plant recruitment. We used Brachystegia spiciformis to investigate the influence of conspecifics and rocks on early seedling recruitment in Cecil Kop Nature Reserve in Zimbabwe. B. spiciformis-dominated woodland was stratified into canopy and gap sites which were further divided into rock and rock-free microsites. In each microsite, we laid 3 blocks of 100 × 100 m and sow seeds of B. spiciformis in five 1 m2 plots close to rocks under canopies (CR), close to rocks in gaps (GR), rock-free in gaps (GF) and rock-free under canopies (CF), making a total of 60 plots. We laid additional 1 m2 plots to quantify the presence of naturally occurring seedlings at 1–12 m distances from boles of 15 trees in four cardinal directions. We found that photosynthetic photon flux density (PPFD), soil and air temperatures were significantly lower in CR, CF and GR than in GF while soil moisture displayed a reverse trend. Although seedling emergence was above 65% in all microsites, more than 60% of the seedlings died because of drought-related mortality which was increased in GF compared with other microsites. Survival probabilty of seedlings was highest in CF and CR, intermediate in GR and lowest in GF. Seedling biomass was increased in GR than under canopies despite higher concentrations of soil organic C, N and P in the latter. The density of naturally occurring seedlings was highest at the parent location than away from it, contradicting the Janzen-Connell recruitment pattern. We conclude that in dry miombo, conservation efforts may be well-served by focusing on the role of nurse objects in the plant recruitment process.

The coastal tailed frog (Ascaphus truei) has a biphasic life-history that includes the use of montane streams adjacent to mature old growth forests. This species is at risk from a variety of land-use activities, including forest harvesting, that results in younger and more fragmented terrestrial habitats. Post-metamorphic tailed frogs are cryptic and difficult to capture, making for few studies of the terrestrial life stage of the species. At the northern extent of the species’ range, we investigated the spatial ecology of tailed frogs across riparian and adjacent upland forest in three forest types: mature to old unharvested, streamside forest retention, and clearcut. Post-metamorphic frogs were fitted with Very High Frequency radio transmitters and monitored for an average of 10.75 days (SE 0.89). Females moved further from their origin of capture during the monitoring period ( x ¯ = 68.89 m, SE 16.3) when compared to males ( x ¯ = 36.85 m, SE 7.9). We used Resource Selection Functions to quantify habitat selection of female and male tailed frogs. Monitored frogs were positively associated with habitats containing well-decayed coarse woody debris (≥ 7.5 cm diameter), less ambient light, adjacency to the larval stream, hygric and subhygric microsites, and cool temperatures (11–12 °C). Females were more selective in their choice of habitat than males. Overall, the relationship between distribution and activity of tailed frogs was reflective of the sex of the frog in combination with microsite or broader climatic conditions ameliorated by stand-level habitat conditions. Our data suggest that habitat management for post-metamorphic tailed frogs focus on the retention of both streamside (within 40 m) and upland forest (> 50 m from larval stream), as well as stand-level attributes such as hygric and subhygric microsites, and coarse woody debris with advanced decay.

Regeneration of coniferous tree species depends on forest structures related to tree death: canopy gaps, decaying wood, and windthrow mounds and pits. This also applies to Norway spruce (Picea abies), which abundantly regenerates from seeds on dead wood and windthrow mounds, and which benefits from gaps in the forest canopy. Accumulated evidence shows much lower mortality of seedlings on elevated structures than on soil, but for saplings the long-term mortality pattern is poorly known. We studied Norway spruce sapling mortality in a natural old-growth subalpine forest in the Western Carpathians (S Poland), tracking the fate of 1304 saplings growing in different conditions. We found that the 25-year sapling mortality rate significantly differed between three types of microsites, being highest on dead wood (49%), intermediate on undisturbed soil (41%) and lowest on mounds (30%). Sapling mortality decreased with increasing canopy openness. Mortality was highest for medium-sized saplings (2–3 m high), regardless of microsite type and mortality cause. For saplings growing on dead wood, mortality increased with increasing decay class of the wood. For those growing on soil, mortality was higher in patches of Athyrium distentifolium than when surrounded by Vaccinium myrtillus and Dryopteris dilatata. We did not detect differences in mortality between saplings growing next to tree trunks and those growing away from them. The pattern of sapling mortality differed from that of seedlings, but it did not change the regeneration pattern over microsites, which is established at the seedling stage. In particular, we believe that the considerable differences in mortality rates between dead wood and the other microsites at the sapling stage cannot counterbalance increased seedling recruitment and survival on dead wood.

Early regeneration, involving the transition from a seed into a successfully recruited seedling, is a complex process characterized by high mortality rates and the strong association with environmental filters. However, we have limited understanding of the factors and transitional regeneration stages that lead to these broad mortality events, even in species that are key for ecosystem function and comprise the bulk of species in diversity assessments, such as Ficus species. Using eight, 1-ha long term monitoring plots, established along an elevation gradient in tropical to subtropical forests in southern China, and partitioning the early plant regeneration process into four stages (seed germination, seedling emergence, establishment and recruitment), we conducted a seed addition experiment to assess the factors driving the early regeneration process. We used four hemi-epiphytic and four non-hemiepiphytic Ficus species, specifically asking whether elevation, microsite conditions and growth form affect the success of regeneration outcomes. We observed that Ficus early regeneration was highly limited throughout the subtropical landscape with similar seed germination probabilities along all elevations, but greater seedling emergence at higher elevations. Growth form and elevation interacted significantly during seed germination and seedling emergence stages. The strongest filtering effect was observed during seedling emergence, with greater canopy openness facilitating, but drier and cooler soils being less conducive to seedling emergence, especially for hemiepiphytic species. Once emerged, Ficus seedlings were released from the environmental filters assessed here, yet, continued to face successively greater mortality during establishment and recruitment. Greater seed germination and seedling emergence on the ground observed in hemiepiphytes indicate that they may benefit from evolutionary traits associated with canopy regeneration under water and temperature stress, but only at the early regeneration stages, as seedling establishment and recruitment were similar in both groups. In general, our results demonstrate that even when seeds are available, successful recruitment is strongly limited by microsite conditions and growth form, through filtering mechanisms associated with the transition from seedling emergence to seedling establishment. The identification of environmental filters that operate during the complex and vulnerable early regeneration stages provides a baseline to develop management strategies for ex situ conservation, as well as in situ population reestablishment for restoration.

The poor natural regeneration of Korean pine represents a substantial hurdle limiting the restoration of secondary forests to mixed broad-leaved Korean pine forests (MBKPFs). Active restoration based on direct seeding or planting seedlings is accordingly considered to be a prerequisite for promoting Korean pine recruitment in secondary forests. To evaluate the most effective practices for restoring Korean pine in secondary forests, we studied the effects of microsites associated with gaps of different sizes and within-gap locations on direct seeding (rodent access/exclusion and soil/litter cover) and seedling planting (1-, 2-, and 3-year-old seedlings). We found that an average of 82.4% of sown seeds were eaten by rodents, with only 9.9% germinating and surviving after two growing seasons. Among the germinated seedlings, 37.6% were subsequently excised by rodents, whereas 6% died due to other natural causes. Furthermore, compared with the control sites (forest understorey), we detected no significant differences among the different microsites with respect to an effective reduction in rodent damage or promotion of seed germination, whereas rodent exclusion was more effective in protecting seeds from predation than the effect of microsite. With regards to planted seedlings, we found that the proportion of survival and relative root collar diameter growth were highest in the center (64.1%) and edge (60.0%) sites of large gaps, and that the survival of planted seedlings (43.7%) was considerably higher than that of seedlings derived from directly sown seeds (9.9%). Collectively, our findings indicate that, owing to seed predation and seedling excision by rodents, direct seeding with either mesh or soil cover would not represent an effective strategy for promoting Korean pine recruitment in secondary forests. Accordingly, for the purposes of restoring secondary forests to MBKPFs, we recommend planting 3-year-old Korean pine seedlings in large gaps within secondary forests.

Tree planting is a common strategy for forest restoration. The use of mid- and late-successional species is less common, but could accelerate succession, enhance diversity and secure their presence. In this study, we determined the survival and growth of 559 saplings from nine native mid- and late-successional species after three years of growth under a range of habitat conditions to evaluate their potential utility in restoration plantings. Since mid- and late-successional tree species have shade-tolerant attributes and the light environment is a determinant factor for their growth and survival, we expected sapling performance to vary among species depending on the percentage of canopy cover and on factors associated with this variable. For this, we identified habitat conditions that influenced sapling performance in a degraded tropical cloud forest: the conditions ranged from closed-canopy secondary forest to open pastures dominated by exotic grasses. Overall, the studied species presented a high performance: sapling survival (40 to 90%) and relative growth rates in height (0.14 to 0.50 cm cm−1 year−1) and in diameter (0.04 to 0.50 mm mm−1 year−1) were within or above the ranges previously reported for cloud forest species. The final sizes and growth rates in height and diameter were mostly explained by the canopy and grass cover (71.5% of the variation). Integrated Response Index (IRI) values showed wide variation among species (from 6.44 to 41.41 with inclusion of height, and from 2.13 to 44.77 with inclusion of diameter). In general, there was a negative correlation between canopy cover and final sapling size and growth rates in height and diameter, but there were important variations among species. Based on their IRI values, species such as Ulmus mexicana and Oreomunnea mexicana are suggested for restoration plantings. Given their low performance, however, Fraxinu uhdei and Juglans pyriformis are recommended for use only in advanced forest successional stages or in conjunction with other restoration techniques to increase their survival. Our results show that these threatened mid- and late-successional native species can be successfully matched to microsite conditions and established in degraded areas as a strategy by which to secure their presence and accelerate forest recovery.

Quaking aspen (Populus tremuloides) is an important component of western U.S. forests, however knowledge concerning processes of aspen seedling establishment, survival, and growth is limited and frequently anecdotal. Following a widespread post-fire establishment event in southern Utah, we explored spatial establishment patterns of >1000 aspen seedlings and tracked their survival and growth for two growing seasons. Specifically, we assessed the influence of landscape-level variables, microsite factors, and competition with suckers on aspen seedling establishment, survival, and growth. Aspen seedlings occurred across large areas of the 29,000 ha fire footprint, with an average plot density of 23,033 seedlings ha−1, and establishment more likely at higher elevations and closer to seed sources. Aspen seedlings preferentially established in concave microsites and were tightly associated with burned soil. A total of 33% of tagged seedlings remained alive after two growing seasons. Seedling persistence was strongly impacted by competition with co-occurring aspen suckers, with survival lower for aspen seedlings closer to nearby suckers and seedling growth reduced in plots with high sucker density. Given the long dispersal distances of aspen seeds and the ability of seeds to take advantage of initial post-disturbance conditions, sexual regeneration in aspen may represent an important pathway for maintaining forest resilience and associated ecosystem services, especially following fires with large patches of high burn severity.

Human-shaped treelines are a common feature in mountain landscapes across Europe, and particularly in secularly managed Mediterranean high-elevation areas. The abandonment of traditional land use, and especially the reduction in grazing pressure at high elevations, triggered secondary succession in treeless grassland areas, and favored the upward shift of anthropogenic treelines in some cases. We investigated this process in four anthropogenic treeline ecotone sites in the Central Apennines, Italy, populated by European black pine (Pinus nigra Arn.). The upward treeline shift was controlled by microsite topography and the proximity to plantations acting as seed source. We found a 50% probability of producing cones in trees with basal diameters of 15–25 cm, heights of 2–5 m and ages of 20–25 years. The role played by climate on growth and the recruitment processes seems to be secondary, or could be masked by human-shaped processes. The presence of reproductive age trees at the treeline, mainly growing on debris-rich and steep slope sites, could indicate that the recruitment process will increase in future, leading to patchy tree patterns at different elevations. The high growth and encroachment rates observed at these human-shaped treelines would indicate that general growth dynamics are speeding up, including the tree colonization of treeless areas. These succession processes could cause a significant long-term decline in plant diversity in species-rich grasslands. Nonetheless, tree encroachment could increase forest protection against landslides and avalanches in the context of global change.

The direct seeding method of artificial regeneration has a long tradition in silvicultural management. The main application of the direct seeding of silver fir (Abies alba Mill.) today occurs in the context of the conversion of Norway spruce stands in central Europe. Although direct seeding is often considered to closely resemble natural regeneration in many respects, tree planting is currently more commonly employed in forestry. Presented in this paper is an extensive historical review showing the variety of facets associated with and experiences of direct seeding gleaned through scientific experiments or based on forestry practice. This review also illustrates the fluctuating practical relevance of the direct seeding of silver fir depending on the prevailing objectives of forest owners, harvesting methods, forest structures and the possibilities for technical implementation. An overview of the available ecological knowledge of the development stages and processes within the natural regeneration cycle of silver fir is provided, highlighting the most relevant environmental factors and the resources determining the success of natural regeneration. Having identified these factors, the individual technical steps involved in direct seeding can be analysed. The means by which the individual steps in the direct seeding approach can be used to manipulate environmental factors and microsite conditions such as the density of overstorey shelter, soil and seedbed preparation, and to reduce competition pressure to optimise the direct seeding of silver fir are outlined. Finally, on the basis of the analyses presented, these complex relationships are integrated in a step by step decision pathway to provide an individual forest stand decision-making process. This ecologically based approach can improve the success of direct seeding and may allow for the adaptation of the direct seeding process to suit individual forest stand conditions. Consequently, the growing efforts to convert and enrich homogenous Norway spruce stands by means of the direct seeding of silver fir can be promoted in a close-to-nature way, while employing controlled silvicultural measures.

Tree recruitment is a spatially structured process that may undergo change over time because of variation in postdispersal processes. We examined seed pilferage, seed germination, and seedling survival in whitebark pine to determine whether 1) microsite type alters the initial spatial pattern of seed caches, 2) higher abiotic stress (i.e. higher elevations) exacerbates spatial distribution changes, and 3) these postdispersal processes are spatially clustered. At two study areas, we created a seed distribution pattern by burying seed caches in microsite types frequently used by whitebark pine's avian seed disperser (Clark's nutcracker) in upper subalpine forest and at treeline, the latter characterized by high abiotic environmental stress. We monitored caches for two years for pilferage, germination, and seedling survival. Odds of pilferage (both study areas), germination (northern study area), and survival (southern study area) were higher at treeline relative to subalpine forest. At the southern study area, we found higher odds of 1) pilferage near rocks and trees relative to no object in subalpine forest, 2) germination near rocks relative to trees within both elevation zones, and 3) seedling survival near rocks and trees relative to no object at treeline. No microsite effects were detected at the northern study area. Findings indicated that the microsite distribution of seed caches changes with seed/seedling stage. Higher odds of seedling survival near rocks and trees were observed at treeline, suggesting abiotic stress may limit safe site availability, thereby shifting the spatial distribution toward protective microsites. Higher odds of pilferage at treeline, however, suggest rodents may limit treeline recruitment. Further, odds of pilferage were higher near rocks and trees relative to no object in subalpine forest but did not differ among microsites at treeline, suggesting pilferage can modulate the spatial structure of regeneration, a finding supported by limited clustering of postdispersal processes.

Understanding tree recruitment is crucial to assess species turnover in mixed forests and woodlands, particularly in light of current anthropogenic impact. Here, we investigate whether oak recruitment (density of young oaks) in co-existing deciduous and evergreen oaks is disproportional to the abundance of their corresponding reproductive trees, favoring regeneration of some species over others, which may anticipate a future species turnover. We also examined whether browsing damage and microsite location play a differential role in such recruitment process. We uncovered an overall underrepresentation of young oaks ( Q. lobata and Q. douglasii ), compared to the evergreen oak ( Q. agrifolia ), even in areas where deciduous species were the locally predominant mature trees. Such differential recruitment was accentuated in areas where Q. lobata was predominant, with young evergreen oaks reaching densities 3-times higher than those of the deciduous oak. Recruitment of all three species was significantly associated with shrub cover, suggesting a facilitative effect, via reduction of both occurrence and intensity of herbivory. However, evergreen oaks were much less vulnerable to herbivory (lower occurrence and intensity) than deciduous oaks and, thus, evergreen recruits were able to thrive even in uncovered areas. Overall, our results provide evidence of differential recruitment at the juvenile stage in co-occurring oak species, which may lead to a replacement of deciduous species with evergreen oaks. The disproportionate effect of shrubs as safe microsites for regeneration of both deciduous and evergreen species suggests that herbivory pressure is an important factor reducing the abundance and heterogeneity of favorable regeneration niches, particularly for the most herbivore-sensitive tree species. Further studies should address to what extent the recruitment patterns described here translate into future differences in adult stages, and whether the actual biased regeneration is mostly due to differential herbivory on deciduous vs. evergreen species. We posit that, for the management and conservation of multi-specific oak savannas, regeneration of deciduous oaks should be prioritized over that of live oaks in order to maintain greater levels of biodiversity and reduce biotic homogenization.

Many studies have shown evidence of very rapid natural colonization of trees on roadslopes. Tree colonization on roadslopes can be a usefultool in the ecological restoration ofthese degraded areas. However, little is known about the characteristics of the tree species capable of colonizing these novel habitats. Moreover, it is necessary to know how tree species respond to the two main limitations in these areas: microsite availability (i.e., roadslope characteristics) and seed arrival, which is related to propagule source, dispersion vector and landscape characteristics. The present study aims to investigate the natural colonization of tree species on roadslopes, as well as the factors determining their occurrence. We identified all tree individuals on 150 roadslopes, along 51 km of a motorway. A total of 1143 individuals belonging to 18 species was recorded. Most individuals found resulted from a natural colonization process, although we found various fruit trees (present in 7 roadslopes) and Robinia pseudoacacia (2 roadslopes), which are probably associated with unintentional human-mediated seed dispersal. Only the six most abundant species were analysed in detail: Populus nigra, Quercus ilex, Quercus pyrenaica, Fraxinus angustifolia, Salix spp. and Ulmus pumila. Each roadslope was characterized both by site variables and by surrounding variables. We analysed the effect of the descriptive variables on the occurrence and density of each species on the roadslopes, and we subsequently used decision trees (classification and regression trees) to analyse the combined effect of the different predictors considered. Our results show successful tree colonization on the roadslopes, although they appear to indicate limitations to colonization associated with the availability of propagules. Furthermore, tree species dispersed by animals required a continuous flow of seeds favoured by an appropriate community of seed dispersers and a suitable landscape structure. By contrast, wind-dispersed tree species basically need favourable site characteristics on the roadslopes.

Restoration of shrubs in arid and semi-arid rangelands is hampered by low success rates. Planting shrub seedlings is a method used to improve success in these rangelands; however, it is expensive and labor intensive. The efficiency of shrub restoration could be improved by identifying microsites where shrub survival is greater. Bitterbrush (Purshia tridentata Pursh DC) is an important shrub to wildlife that has declined because of conifer encroachment, excessive defoliation, wildfires, and low recruitment. We investigated planting bitterbrush seedlings in western juniper (Juniperus occidentalis ssp. occidentalis Hook) encroached shrublands after prescribed fire was used to control trees. Bitterbrush seedlings were planted in under (canopy) and between (interspace) former juniper canopies at five blocks and evaluated for three growing seasons. Bitterbrush survival was greater than 50% in the former canopy, but only 5% in the interspace microsite by the third growing season. Growth of bitterbrush was also greater in the former canopy compared with the interspace, potentially due to markedly less perennial vegetation in this microsite. Exotic annual grasses and annual forbs became prevalent in the former canopy in the second and third growing season, suggesting that soil resource availability was greater in this microsite. These results suggest that restoration success will vary by specific locations within a burned landscape and that this variability can be used to improve restoration efficiency. In this situation, bitterbrush restoration can be improved by planting seedlings in former canopy compared with interspace microsites.

Identifying optimal transplant size and microsite requirements are critical challenges facing restoration practitioners, and refining this information may lead to more cost effective decisions. In this study, we evaluate the effects of transplant size and microsite on restoration success of the federal threatened Cirsium pitcheri (Pitcher’s thistle), a monocarpic perennial restricted to shoreline sand dunes of the Great Lakes in the United States, using a ten-year dataset. Using general and generalized mixed linear models, we determined how microsite variables influenced first-year-transplant survival and subsequent growth. Our data show a higher probability of first-year survival associated with larger transplants. We also found greater plant growth at higher elevations while plants on steeper slopes are smaller the year after they are transplanted. These results have implications for restoration success, which may be maximized by regulating transplant size and selecting habitat.

Coastal sand dunes near the Baltic Sea are a dynamic environment marking the boundary between land and sea and oftentimes covered by Scots pine (Pinus sylvestris L.) forests. Complex climate-environmental interactions characterize these ecosystems and largely determine the productivity and state of these coastal forests. In the face of future climate change, understanding interactions between coastal tree growth and climate variability is important to promote sustainable coastal forests. In this study, we assessed the effect of microsite conditions on tree growth and the temporal and spatial variability of the relationship between climate and Scots pine growth at nine coastal sand dune sites located around the south Baltic Sea. At each site, we studied the growth of Scots pine growing at microsites located at the ridge and bottom of a dune and built a network of 18 ring-width and 18 latewood blue intensity chronologies. Across this network, we found that microsite has a minor influence on ring-width variability, basal area increment, latewood blue intensity, and climate sensitivity. However, at the local scale, microsite effects turned out to be important for growth and climate sensitivity at some sites. Correlation analysis indicated that the strength and direction of climate-growth responses for the ring-width and blue intensity chronologies were similar for climate variables over the 1903–2016 period. A strong and positive relationship between ring-width and latewood blue intensity chronologies with winter-spring temperature was detected at local and regional scales. We identified a relatively strong, positive influence of winter-spring/summer moisture availability on both tree-ring proxies. When climate-growth responses between two intervals (1903–1959, 1960–2016) were compared, the strength of growth responses to temperature and moisture availability for both proxies varied. More specifically, for the ring-width network, we identified decreasing temperature-growth responses, which is in contrast to the latewood blue intensity network, where we documented decreasing and increasing temperature-growth relationships in the north and south respectively. We conclude that coastal Scots pine forests are primarily limited by winter-spring temperature and winter-spring/summer drought despite differing microsite conditions. We detected some spatial and temporal variability in climate-growth relationships that warrant further investigation.

Northern Australia's savannas are among the most fire‐prone biomes on Earth and are dominated by eucalypts (Eucalyptus and Corymbia spp.). It is not clear what processes allow this group to dominate under such extreme fire frequencies and whether a superior ability to compete for nutrients and water might play a role. There is evidence that eucalypts are adapted to frequent fires; juvenile eucalypts escape the fire trap by growing rapidly in height between fires. However, non‐eucalypts are less able to escape the fire trap and tend to have stand structures strongly skewed toward suppressed juveniles. The mechanisms that drive these contrasting fire responses are not well understood. Here, we describe the results of a controlled glasshouse seedling experiment that evaluated the relative importance of nutrient and water availability in determining height growth and biomass growth of two eucalypt and one noneucalypt tree species, common in northern Australian savannas. We demonstrate that growth of eucalypt seedlings is particularly responsive to nutrient addition. Eucalypt seedlings are able to rapidly utilize soil nutrients and accumulate biomass at a much greater rate than noneucalypt seedlings. We suggest that a seasonal spike in nutrient availability creates a nutrient‐rich microsite that allows eucalypt seedlings to rapidly gain height and biomass, increasing their likelihood of establishing successfully and reaching a fire‐resistant size. Our results extend our understanding of how eucalypts dominate northern Australian savannas under extremely high fire frequencies., In the northern Australian savannas, eucalypts are adapted to frequent fires; juvenile eucalypts escape the fire trap by growing rapidly in height between fires. However, non‐eucalypts are less able to escape the fire trap and tend to have stand structures strongly skewed towards suppressed juveniles. The mechanisms that drive these contrasting fire responses are not well understood. We suggest that a seasonal spike in nutrient availability allows eucalypt seedlings to rapidly gain height and biomass, increasing their likelihood of reaching a fire‐resistant size and dominant recruitment.

Soil erosion affects extensive areas worldwide and must be urgently reduced promoting plant cover and beneficial microorganisms associated with plants, including arbuscular mycorrhizal fungi (AMF). In mountain environments, plant cover is difficult to enhance due to harsh conditions during the dry season and steep slopes. Our objective was to evaluate the percentage of the soil surface covered by plants and the AMF community associated with trees 12.5 years after planting during forest restoration efforts in microsites at different levels of soil degradation. The study was performed in the first montane forest restoration initiative of Central Argentina, where one of the trials consisted of planting Polylepis australis saplings at microsites with different levels of soil degradation: high, intermediate, and low. After 12.5 years, percentage of bare soil cover was significantly reduced by 36 and 37% in the high and intermediate degradation microsites, respectively. Low degradation microsites were initially very low in bare soil and did not significantly change. Mycorrhizal colonization, hyphae, vesicles, arbuscules, AMF diversity, and community structure were similar among microsite types. Percentage of hyphal entry points was higher at microsites with low degradation, number of spores was higher in high and intermediate degradation, and species richness was higher in high degradation. Acaulospora and Glomus were the most abundant genera in all microsites. We conclude that even in the most degraded microsites around 2.8% of the bare soil is covered by vegetation each year and that the arbuscular mycorrhizal community is highly tolerant and adapted to soils with different disturbance types. Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Divan, Adriana Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Renison, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina

Conifer mountain forests influence a large portion of the World’s human population by providing a host of critical economic, sociological, and ecosystem services. Although the causes of the elevational, transitional boundaries of these forests (i.e. upper and lower timberlines) have been questioned for over a century, these investigations have focused predominately on the growth limitations of saplings or mature trees at the upper alpine boundary. Yet, the elevational movement of timberlines is dependent initially on new seedling establishment in favorable microsites that appear to be generated by ecological facilitation. Recent evidence suggests that this facilitation is critical during the initial 1-2 years of growth when survival may be less than a few percent, only cotyledons are present, and survival occurs only in favorable microsites created by inanimate objects (e.g. boulders, dead stems), microtopography, or already established vegetation. Dramatic changes in tree form (e.g. krummholz mats) across the timberline ecotone also plays an important role in generating microsite facilitation. These favorable, facilitated microsites have been characterized broadly as experiencing low sky exposure during summer (day and night) and leeward wind exposure during winter that generates protective snow cover, all of which are needed for new seedling survival. Thus, determining the specific microclimate and edaphic characteristics of favorable microsites, and their frequency at timberline, will provide a more mechanistic understanding and greater predictability of the future elevation and extent of conifer mountain forests. In addition, although the ecophysiological advantages of a needle-like leaf morphology is well established for adult conifer trees, the advantage of this phylogenetically unique trait in emergent seedlings has not been thoroughly evaluated. Understanding seedling ecophysiology and the functional morphology that contributes to survival, plus the nature and frequency of favorable microsites at timberline, will enable more reliable estimates of future elevational shifts in conifer mountain forests. This approach could also lead to the development of a valuable and sensitive tool for forest managers interested in evaluating future changes in these forests under increased large-scale infestation and drought mortality, as well as for current scenarios of predicted climate change.

The framework species method (FSM) of forest restoration involves planting mixtures of native forest trees to catalyze or complement natural regeneration and accelerate recovery of a diverse understory in tropical forests. Data on naturally regenerating tree seedlings, however, is sparse, and we lack an understanding of how environmental factors affect seedling persistence and growth. We investigated relationships between microsite light availability and two-year survival and growth of naturally-recruited tree seedlings in 11- to 14-year-old FSM trial plots, established to restore seasonally dry tropical forest (SDTF) in the highlands of northern Thailand. We also explored relationships among seedling survival, growth, successional guild and leaf habit. We sampled seedlings belonging to 13 tree species, representing various successional guilds (pioneer, intermediate and late-successional) and leafing habits (evergreen and deciduous). They included seedlings of “overstory species,” species planted to establish the plots, and “re-colonizing species,” species recruited into the plots by seed-dispersal from outside. Seventy-two percent of sampled seedlings survived two years. Ten species had high two-year survival (≥69%); however, three deciduous pioneer species had low survival ( R m 2 = 0.230 ) or RGRD ( R m 2 = 0.138 ) suggesting that there are additional, unconsidered factors important to growth. High two-year seedling survival indicated that within 14 years of implementing the FSM, the understory environment had become adequate for regeneration of a wide range of tree species. Regeneration of re-colonizing species confirmed previous reports that the FSM fosters regeneration of species-diverse tree communities. The results suggested that thinning or gap creation, to increase light levels, may accelerate seedling growth, but are not essential for regeneration of the studied species, and that enrichment planting or direct seeding of intermediate and late-successional species would help to accelerate ecosystem diversification. Introducing such species just before canopy closure and before planted overstory trees become reproductive may provide them with a competitive advantage over seedlings of overstory species.

Karst region has a high rate of rock exposure, shallow and discontinuous soil, and a fragile ecological environment. However, these special habitats encompass a large area of forest with strong original nature-karst deciduous broad-leaved and evergreen mixed forest. So far, very limited information is available on the spatial patterns and internal maintenance mechanism of this community. To fill this gap, the spatial distributions together with spatial correlations of both the live and dead trees in the karst primary forests of the Maolan National Nature Reserve in China were explored by using univariate as well as bivariate g(r) functions. The results revealed that: (1) the habitat heterogeneity of the karst primary forest has insignificant influence at a larger scale (>10 m); (2) the decline in aggregation with the increasing size classes from saplings to adults suggests self-thinning process, proving that negative density constraints occurred in early life stages; (3) positive spatial correlation was found in live trees with similar diameters, which related to the microsite heterogeneity; (4) the aggregation of dead trees and non-attraction of dead and surviving trees indicated scramble competition; (5) mortality analysis indicated the absence of random mortality, favoring positive density-dependent effects; (6) strong initiation sprouting regeneration was one of the main self-renewal strategies, and regeneration was more likely to occur at the edge of the gap rather than under the gap. Our results support the view that the mechanisms underlying the observed spatial patterns were related to certain ecological processes and their interaction. These were the positive and negative density dependence, scramble competition, and microsite heterogeneity.

Widespread impacts of changes in land use, climate, and disturbance regimes continue to affect mature forests and their subsequent post-disturbance recovery. In South American temperate rainforests, the recovery of the original composition, structure, and ecological services of now-degraded old-growth forests is additionally hampered by the aggressive competition that the native Chusquea bamboo understory exerts on juvenile trees, thus arresting ecological succession. In this study, we aim to evaluate the early performance of Nothofagus nitida seedlings (pioneer tree species that tolerate shade) planted beneath nurse canopy following removal of the understory, and to define which microsite conditions can facilitate N. nitida growth. For this, we monitored 45 N. nitida plantings established in 2014 in Chiloe Island (North Patagonia, Chile) for five years. After this period, planted seedlings presented relatively good indicators of performance with low mortality (~30% of dead seedlings), good vitality (~60% of healthy seedlings), and relatively high mean periodic annual increments in root collar diameter and height (~1.7 mm/year and ~17.4 cm/year, respectively). Furthermore, our results show that the planted N. nitida seedlings can tolerate and grow under low-light conditions, though their diameter and height increase significantly with higher light availability. However, physiological stress of planted seedlings increased in open areas with more available light and planted seedlings were most stressed during the summer season. Increased summer-season stress was attributed to the months with highest depth of the water table, highest maximum and mean photosynthetic active radiation (PAR) values, highest temperature, and lowest precipitation. Our results show for first time with field-based data that different microsite and canopy conditions facilitate the initial performance of N. nitida plantings after removal of the Chusquea bamboo understory. In this context, we conclude that the removal of the Chusquea bamboo understory is the key to overcome arrested succession of coastal temperate rain forests Furthermore, supplementary planting of pioneer tree species that tolerate shade, like N. nitida, assists natural forest recovery, especially in humid and open sites with some protection of a nurse canopy.

The extent to which small shifts among local topographic microsites could mitigate the effects of larger-scale climate change in arctic–alpine systems including mountain top organisms is largely unknown. This study is among the first to evaluate the relative contribution of microsite and altitude as a proxy for climate change on saxicolous lichen communities. We registered 107 lichen species in 54 boulders ranging from 900 to 2700 m.a.s.l. and in a large array of microsites in central Argentina. Communities ordinated along NMS multivariate analysis axes 1, 2 and 3 presented a cumulative R2 of 80%. The three axes were explained by altitude with axis 1 only being explained by altitude. Axis 2 was also explained by slope and aspect whereas axis 3 was explained by the interaction of altitude with aspect indicating that aspect was important only at lower altitudes but not at the mountain top. Lichen cover and richness were similar throughout the altitudinal gradient. We interpret that under a climate warming scenario, lower altitude species occupying pole ward facing slopes will have to migrate upwards while at the mountain top—for most communities-there still is scope for microsite segregation to compensate climate change. Fil: Rodriguez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina Fil: Renison, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina Fil: Filippini, Edith Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina Fil: Estrabou, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina