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Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km 2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km 2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications., (© 2022 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

Current analyses and predictions of spatially explicit patterns and processes in ecology most often rely on climate data interpolated from standardized weather stations. This interpolated climate data represents long-term average thermal conditions at coarse spatial resolutions only. Hence, many climate-forcing factors that operate at fine spatiotemporal resolutions are overlooked. This is particularly important in relation to effects of observation height (e.g. vegetation, snow and soil characteristics) and in habitats varying in their exposure to radiation, moisture and wind (e.g. topography, radiative forcing or cold-air pooling). Since organisms living close to the ground relate more strongly to these microclimatic conditions than to free-air temperatures, microclimatic ground and near-surface data are needed to provide realistic forecasts of the fate of such organisms under anthropogenic climate change, as well as of the functioning of the ecosystems they live in. To fill this critical gap, we highlight a call for temperature time series submissions to SoilTemp, a geospatial database initiative compiling soil and near-surface temperature data from all over the world. Currently, this database contains time series from 7,538 temperature sensors from 51 countries across all key biomes. The database will pave the way toward an improved global understanding of microclimate and bridge the gap between the available climate data and the climate at fine spatiotemporal resolutions relevant to most organisms and ecosystem processes., (© 2020 John Wiley & Sons Ltd.)

The four alien farmland weeds of genus Veronica (i.e. V. arvensis , V. didyma , V. hederifolia and V. persica) have successfully colonized in China, but caused different ecological consequences in the colonized habitats. However, the key biological traits conferring bioinvasion differences under different light conditions among the four alien species of Veronica remain unknown. A comprehensive contrastive analysis experiment was conducted to assess the contribution of the intensity of photosynthetic and sexual and asexual reproductive traits of the four alien Veronica weeds to their invasion level in both field trial and laboratory. The field survey showed that V. persica had the highest invasion level, followed by V. didyma , V. hederifolia and V. arvensis. Their invasiveness was mainly attributed to photosynthetic-related parameters (LMA) and asexual reproduction traits (the ratio of adventitious roots) out of all the 22 tested indexes. The photosynthetic-related and some asexual reproduction indexes from separate determinations under both sun and shade conditions showed that V. persica was able to adapt to strong illumination but was more tolerant of shade than the other species. This adaptive differentiation to illumination conferred different competitiveness over crops on the four alien Veronica weeds by allocating resources to the biomass of each organ in farmland. It may be concluded that the adaptability to illumination conditions and the asexual reproduction traits may endow their successful invasion and become different important farmland weeds. [ABSTRACT FROM AUTHOR]

The timing of flowering and fruiting events is an important trait for explaining plant invasion. Seasonally dry ecosystems are characterized by a restricted growing season which imposes limitations on species reproduction. In these ecosystems to succeed, non-native species may have one of two phenological strategies. Coupled phenology with natives might be a product of an adjustment to environmental filters, exposing open flowers altogether, thus increasing the possibility of diluting some antagonist interactions but also mutualistic ones. Conversely, tolerating a wider range of environmental conditions might generate uncouple phenology, due to using a Vacant niche or having longer phenological periods. Previous evidence observed that non-natives have divergent strategies with natives in these ecosystems; thus, we expect to find uncoupled phenology. This uncoupled phenology may be associated with changes in the timing or length of the reproductive period. The aim of this work was to analyze the flowering and fruiting phenological strategies developed by the most frequent native and non-native woody species through a multi-year study. We measured the beginning and length of flowering and fruiting of sixteen species during four consecutive reproductive periods. We found that the phenology of non-native species was uncouple with natives. Non-natives showed a delay in flowering and fruiting and had a longer fruiting phenology period. Moreover, unlike the natives, non-natives fruited out of the growing season. The different phenological strategies found in non-native species may generate different interactions and windows of opportunities that may explain invasion and have profound consequences on ecosystem processes and functions. [ABSTRACT FROM AUTHOR]

Determining traits correlated with invasiveness in order to identify potentially invasive species remains a priority in the field of invasion ecology. In trees, relative growth rate (RGR), specific leaf area (SLA), or plant height under optimal growing conditions have been identified as performance traits allowing pioneer exotic species to outcompete native species. However, few studies investigated the link between these traits and invasiveness on a continuous scale. Here, we compare the RGR, SLA, height, shoot–root ratio, and number of leaves of seedlings of eight maple species (Acer spp.) with their invasiveness at the global level. Seedlings were grown in non-limiting conditions indoor in Gembloux, Belgium and harvested after 2, 4, or 8 weeks. Global invasiveness was quantified using a combination of the number of regions and countries invaded in the GBIF database, the number of citations in the Global Compendium of Weeds (GCW), and the risk score estimated in the GCW. RGR, SLA, height, and number of leaves after 8 weeks were positively correlated with invasiveness. We conclude that invasive maple species could benefit from an acquisitive strategy and that high growth and light capture also favor invasiveness of shade-tolerant species. Finally, we recommend a close monitoring of Acer rufinerve in Western Europe due to its high RGR and SLA, comparable to other highly invasive maple species. [ABSTRACT FROM AUTHOR]

Canopy habitats challenge researchers with their intrinsically difficult access. The current scarcity of climatic data from forest canopies limits our understanding of the conditions and environmental variability of these diverse and dynamic habitats. We present 307 days of climate records collected between 2019 and 2020 in the tropical rainforest canopy of the Yasuní National Park, Ecuador. We monitored climate with a 10-min temporal resolution in the middle crowns of eight canopy trees. The distance between canopy climate stations ranged from 700m to 10 km. Apart from air temperature, relative humidity, leaf wetness, and photosynthetically active radiation (PAR), measured in each canopy climate station, global radiation, rainfall, and wind speed were measured in different subsets of them. We processed the eight data series to omit erroneous records resulting from sensor failures or lack of the solar-based power supply. In addition to the eight original data series, we present three derived data series, two aggregating canopy climate for valleys or for ridges (from four stations each), and one overall average (from the eight stations). This last derived data series contains 306 days, while the shortest of the original data series covers 22 days and the longest 296 days. In addition to the data, two open-source tools, developed in RStudio, are presented that facilitate data visualization (a dashboard) and data exploration (a filtering app) of the original and aggregated records. [ABSTRACT FROM AUTHOR]

Whether facilitation from native plants is strong enough to trigger community dominance by non-natives remains unclear. We explored the possibility that facilitation from Prosopis caldenia, the dominant native tree in the semiarid open forest of central Argentina, drives local community dominance by Chenopodium album, an annual herb native to Europe. We assessed this hypothesis by conducting extensive field sampling in which we recorded the relative abundance of species growing under the canopy of P. caldenia (caldén microsites) and in adjacent locations free of this tree (open microsites). If our hypothesis is correct, then the relative abundance of C. album will be greater than that of the rest of the species only when growing under P. caldenia. Also, we measured C. album performance, estimated its soil seed bank, and characterized growing conditions in caldén and open microsites. We found that the relative abundance of C. album was over seven times greater than that of any other species in communities occurring in caldén microsites; by contrast, C. album co-dominated communities with several other species in the open. Chenopodium album density, cover, biomass, and fecundity were all several times greater in caldén than open microsites. Similarly, C. album seed bank displayed an eight-fold increase in caldén as compared to open microsites. Growing conditions were markedly different between microsites, which could explain positive responses from C. album. Our results suggest that facilitation from natives is indeed strong enough to trigger local community dominance by non-natives, advancing the understanding of community-level consequences of this interaction. [ABSTRACT FROM AUTHOR]

The magnitude and frequency of soil frost events might increase in northern temperate regions in response to climate warming due to reduced insulation caused by declining snow cover. In temperate deciduous forests, increased soil frost severity can hamper tree growth and increase the mortality of fine roots, soil fauna and microorganisms, thus altering carbon and nutrient cycling. From single-site studies, however, it is unclear how the sensitivities of these responses change along continental gradients from regions with low to high snowfall. We conducted a gradient design snow cover and soil temperature manipulation experiment across a range of lowland beech forest sites to assess the site-specific sensitivity of tree growth and biogeochemical cycling to soil cooling. Even mild and inconsistent soil frost affected tree increment, germination, litter decomposition and the retention of added 15N. However, the sensitivity of response (treatment effect size per degree of warming or cooling) was not related to prevailing winter climate and snow cover conditions. Our results support that it may be valid to scale these responses to simulated winter climate change up from local studies to regional scales. This upscaling, however, needs to account for the fact that cold regions with historically high snowfall may experience increasingly harsh soil frost conditions, whereas in warmer regions with historically low snowfall, soil frost may diminish. Thus, despite the uniform biotic sensitivity of response, there may be opposing directions of winter climate change effects on temperate forests along continental temperature gradients due to different trends of winter soil temperature. [ABSTRACT FROM AUTHOR]

Across the continents, plant invasion is identified as one of the main threats to ecosystem functioning and stability. The main objective of this research was to evaluate the differences in the functional traits between invasive alien (Ageratina adenophora (Spreng.) and Lantana camara L.) and native (Berberis asiatica Roxb. Ex DC., Pyracantha crenulata (D. Don.) M. Roemer and Rubus ellipticus Sm.) shrub species of chir pine (Pinus roxburghii Sarg.) forest in the central Himalaya. Three 0.5 hectare chir pine forest stands were selected and individuals of similar diameter were tagged for comparative studies of leaf traits, growth pattern, and biomass accumulation in structural organs of each invasive alien and native species. Our one-way ANOVA and Tukey's post hoc test results showed that both the invasive alien species have significantly (p < 0.05) higher SLA, LWC, total chlorophyll content, foliar nutrient (N and P), RGR, LMR, SMR, nutrient uptake, and nutrient use efficiencies than native species. Leaf litter decomposition rate and nutrient release were also significantly (p < 0.05) higher in both the invasive alien species. Native species, R. ellipticus, shared some of the traits, such as leaf area, chlorophyll content, RGR, LAR, LMR, and nutrient uptake efficiency with invasive alien species. The majority of traits differed among invasive alien and native species, implying that the success of invasive alien species is best described by being functionally distinct from native species. These findings indicate that invasive alien species had advanced functional traits which may be playing an important role in a rapid spread in the central Himalaya. [ABSTRACT FROM AUTHOR]

Premise of research. Plant silica content depends on the phylogenetic position of a taxon; however, biological or ecological factors may also affect it. In this work, we analyzed data on silicophytolith content from 105 species of South America, examining, in a phylogenetic context, its relationship with anatomy and ecological features such as life cycle, growth form, plant origin, and environmental preferences. Methodology. Data on the silicophytolith content and bioecological features of the species were obtained from published and unpublished sources. The relations between systematics, silica content, and bioecological variables were analyzed through measurements of phylogenetic signal and phylogenetic generalized least squares regressions. Pivotal results. Eighty-six percent of the species produced between 0.38% and 19% of silicophytolith dry weight in leaves. Silica content was variable between and within clades. Values of λ and K indicate a low phylogenetic signal for the variable silica content. Dicotyledons accumulated silica in typical epidermal cells, and a few families also stored it in cystoliths. Most of the monocot families showed high silicophytolith contents and a high diversity of silicified cells. Plant origin affected the silica contents: exotic species accumulated more than native ones. On the other hand, no statistical relationship was found between silica content and the other ecological variables. Conclusions. Silicophytolith accumulation is a common feature in most of the species studied. The low phylogenetic signal of silica content is explained by inter- and intraclade variability, which in turn supports the hypothesis that silicophytolith accumulation is a homoplasic character among plants. On the basis of the overall analysis of silicophytolith content and tissue distribution, high content could be related to the specific accumulation mechanisms and roles of silica. The origin of the plant was the only bioecological variable that influenced plant silica content. This finding may indicate some ecological role for silica in exotic plants involving their success in novel environments. [ABSTRACT FROM AUTHOR]

Herbivore and plant invasions can modify the structure and functioning of ecosystems through positive interactions that facilitate their mutual establishment. An important consequence of the feeding behaviour of rabbits is that they can play a key role in seed dispersal by endozoochory. We examined the diet and potential for dispersing Rosa rubiginosa and R. canina (Rosa spp.) of European rabbits introduced in a semiarid protected area of Argentina. We found entire seeds in 100% of the samples of Rosa spp. analysed (n = 11, 187 pellets). Our results indicate that the passage of Rosa spp. seeds through the digestive tract of rabbits (64%) did not diminish their viability in comparison to the seeds taken directly from fruits (66%) (χ2 = 0.09, p > 0.05). This study has identified new positive interactions between an invasive mammal and two invasive plants, a finding that suggests that these invader complexes could have a reciprocal effect on one another, which would potentially aid their invasive process in a semiarid protected area of Argentina. [ABSTRACT FROM AUTHOR]

Rubus ulmifolius is a highly invasive species that negatively affects biodiversity, especially on Robinson Crusoe Island (RCI), one of the two global mini-hotspots of vascular plants. The rust Phragmidium violaceum has been used as a biological control agent for some Rubus species in mainland Chile, New Zealand and Australia. We aim to quantify P. violaceum pathogenicity over R. ulmifolius on RCI, under both field and laboratory conditions, to determine its potential as a biological control. In addition, in order to broaden our knowledge about the pathogenicity of P. violaceum from RCI, it was also tested on a highly susceptible Rubus species: R. cf. constrictus. We sampled four forest sites on RCI, measuring abiotic, micro-site, and vegetation variables that could be related with infection. In the laboratory, we inoculated P. violaceum into R. ulmifolius seedlings from RCI and R. cf. constrictus seedlings from mainland Chile. We found a low infection incidence in the field, where only 62 of 182 plots presented infected individuals. Applying a fitted generalized linear model, we predicted ten times more infection of P. violaceum on R. ulmifolius when located in southern aspect slopes and shallow soils (< 30 cm). In the laboratory we determined that rust from RCI infected R. ulmifolius individuals from the island in low density, and did not infect R. cf. constrictus; this low infection rate reinforces our field results. The low infection on R. cf. constrictus may mean that P. violaceum from RCI could originate from very impoverished genetic material. We recommend testing different rust genetic origins, mainly from the Old World, to increase their genetic diversity. [ABSTRACT FROM AUTHOR]

Mining has played an important role in the generation of economic wealth since colonial times in South America. However, the impact of historical mining on the environment has not been studied in detail. In view of this, and based on the analysis of archaeological and modern wood data, we discuss the impact of historical mining and human occupation on the woody vegetation of an arid region in the southern Andes. We present the results of the analysis of archaeobotanical charcoal remains recovered from the "Los Hornillos" mining site located in the Andean Precordillera, northwestern Mendoza Province, Argentina. The archaeobotanical materials date from the late 18th to the early 19th century. Based upon wood anatomy, 60% of charcoal fragments were associated with Adesmia cf. uspallatensis, a shrub widely distributed there. We assessed the impact and legacy of human occupation on local and regional plant communities based on charcoal evidence, archaeological data and the age of living A. uspallatensis shrubs growing around the mining site. This analysis allowed us to determine the rate of growth of this species (1.22 mm per year) and mean maximum ages of around 70 years. Therefore, the current development of woody communities in this area is thought to be representative of recovery after historical mining and occupation across the Andean Precordillera and suggests that obtaining firewood for mining activities constituted an important factor influencing past natural vegetation dynamics. [ABSTRACT FROM AUTHOR]

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For centuries, the dry grassland of the plain of La Crau (south-eastern France) has been subjected to numerous disturbances resulting in the destruction and the fragmentation of this emblematic rangeland ecosystem of the Mediterranean. Today, this ecosystem is facing a new threat from a proliferating native species, the bramble ( Rubus ulmifolius Schott), which preferentially colonizes areas that were formerly cultivated and/or exposed to water infiltration. To identify a strategy for effective control of this colonization, in situ experiments testing disturbance regimes (shrub clearing and/or mixed grazing by sheep and goats) combined with the control of access to water resources (with or without drainage trenches) were undertaken between 2010 and 2013. Only clearing and grazing combined over 3 years led to significant changes in vegetation height and bramble cover as well as modifications in the floristic composition, diversity, similarity, and richness of the plant community. Neither a clearing operation carried out in 2010 alone, nor grazing alone, reduced bramble cover, and neither treatment increased the species richness of the plant community. Similarly, digging drainage trenches had no significant impact either on the plant community or on bramble cover. Our study suggests that only annual mechanical clearing coupled with sheep and goats grazing can significantly reduce bramble cover. This combined restoration treatment needs to be applied for at least 3 consecutive years to induce significant changes and enable this ecosystem to return to the dry grassland succession. [ABSTRACT FROM AUTHOR]