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The invasion of natural communities by exotic plants, which may turn into invasive or potentially invasive, is one of the most severe known threats to biodiversity, and coastal dunes are among the most affected habitats. Mexico’s coastal dunes are abundant and contain high plant biodiversity but attempts to determine the occurrence and impact of exotic plants are absent. First, we explored the number of invasive plant species found on Mexican coastal dunes. Second, we analyzed if the coastal dune flora native from Mexico acts as a source of invasive species worldwide. We found the relevant spread of exotic plants towards and from Mexico, reaching high percentages: 5% of the coastal dune flora are considered exotic plants, this increases to 8.7% when only plants typical of the coastal dune environment are considered. The Mexican coastal dunes flora is also a relevant source of invasive plants affecting all continents. Furthermore, almost half of the 35 worst worldwide invasive plants (according to the Global Invasive Species Database GISD) grow on Mexican coastal dunes, most native to Mexico and invasive elsewhere. Indeed, the worldwide exchange of coastal dune flora between Mexico and the world seems massive, relevant and highlights the need for worldwide and countrywide management and control strategies.

Introduction: Numbers of alien plant species are rising around the globe, but not all of them become invasive. Whereas introductions have been documented for several decades in some regions of the world, knowledge on alien species in Western Mexico is limited. Here, we study roadside vegetation along an elevational gradient, which includes a protected area. Objective:We analysed the floristic composition of herbaceous alien species, their distribution patterns, and their relationship with various environmental factors. A relative importance value index (IVI) identified the most important and, therefore, probably invasive taxa. Methods:During 2017 and 2018, roadside vegetation was documented with 4-6 transects every 300 altitudinal meters, from 0 to 2 100 m, for a total of 37 transects. Each transect consisted of five 1 m² plots. All herbaceous species were registered and alien taxa identified. A cluster analysis distinguished grouping of species based on elevation. The potentially invasive species were identified by their IVI, based on the sum of relative frequency and density values. The influence of environmental variables was analysed with a canonical correspondence analysis. Results:Most alien species were grasses; other families were represented by one or two species. The species were grouped into three main clusters. The first group included rare species, the second consisted of species restricted to higher altitudes, and the third group were tropical taxa with a distribution from sea level to medium altitudes. The most important potentially invasive species were: Urochloa maxima, Melinis repens, Eragrostis ciliaris andCynodon dactylon, all African grasses introduced for grazing. The IVI of the species was related to tree cover, leaf litter depth and surface stone cover for some species and, for others, to soil compaction, distance to major roads and elevation. Conclusions:The alien ruderal species clustered according to the general climate (temperate vs. tropical). Grasses of African origin are of highest concern as invasive species. Although most introductions are related to human disturbance, each species becomes dominant under certain environmental conditions. Thus, management programs must be specifically adjusted to each individual invasive alien. Introducción:El número de especies de plantas exóticas está aumentando en todo el mundo, pero no todas las especies se convierten en invasoras. Si bien para algunas regiones la introducción de especies se ha documentado durante varias décadas, para el occidente de México los conocimientos sobre especies exóticas son escasos. Aquí, estudiamos la vegetación de los bordes de las carreteras a lo largo de un gradiente altitudinal en una región que incluye un área protegida. Objetivos:Estudiamos la composición florística de las herbáceas exóticas, sus patrones de distribución y su relación con diversos factores ambientales. El índice de valor de importancia (IVI) de las especies identificó las especies más importantes, y por lo tanto probablemente invasoras. Métodos: Durante el 2017 y 2018 se documentó la vegetación del borde de la carretera con 4-6 transectos en cada nivel de elevación de 300 m, de 0 a 2 100 m, para un total de 37. Cada transecto constó de cinco parcelas de 1 m². Se registraron todas las especies herbáceas y se identificaron las especies introducidas. Un análisis de agrupamiento identificó los grupos de especies basado en sus patrones de distribución relacionadas con la elevación. Las especies potencialmente invasoras se identificaron por su IVI, basado en la suma de la frecuencia relativa y la densidad relativa. La influencia de las variables ambientales fue estudiada mediante un análisis de correspondencia canónica. Resultados:La mayoría de las especies exóticas fueron pastos, otras familias estuvieron representadas por una o dos especies. Las especies formaron tres grupos principales. El primero incluyó especies raras; el segundo las especies distribuidas principalmente en elevaciones altas, y el tercero incluyó los taxones con una distribución desde el nivel del mar hasta elevaciones medias. Las especies más importantes y potencialmente invasoras fueron: Urochloa maxima, Melinis repens,Eragrostis ciliaris yCynodon dactylon,todas gramíneas africanas introducidas como forraje para el ganado. El IVI de las especies se relacionó con la cobertura de árboles, profundidad de hojarasca y con pedregosidad para algunas especies, y para otras con la compactación del suelo, la distancia a carreteras (federales) y elevación. Conclusiones:Las especies ruderales exóticas se agruparon según el clima general (templado vs. tropical). Las gramíneas de origen africano son las que más preocupan como especies invasoras. Aunque la mayoría de las introducciones están relacionadas con las alteraciones humanas, cada especie se vuelve dominante en determinadas condiciones ambientales. Por ello, los programas de manejo deben ajustarse específicamente a cada especie exótica invasora.

Biological invasions are a leading cause of rapid ecological change and often present a significant financial burden. As a vibrant discipline, invasion biology has made important strides in identifying, mapping, and beginning to manage invasions, but questions remain surrounding the mechanisms by which invasive species spread and the impacts they bring about. Frequent, multiscalar ecological monitoring such as that provided through the National Ecological Observatory Network (NEON) can be an important tool for addressing some of these questions. We articulate a set of major outstanding questions in invasion biology, consider how NEON data science is positioned to contribute to addressing these questions, and provide suggestions to help equip a growing contingent of NEON data users in solving invasion biology problems. We demonstrate these ideas through four case studies examining the mechanisms of plant invasions in the U.S. Intermountain West. In Case Study I, we evaluate the relationships between native species richness, non‐native species richness, and probability of invasion across scales. In Case Studies II and III, we explore the relationship between environmental factors and non‐native species presence to understand invasion mechanisms. Case Study IV outlines a method for improving the ability to distinguish invasive plants from native vegetation in remotely sensed data by leveraging temporal patterns of phenology. There are many novel elements in the NEON sampling design that make it uniquely poised to shed light on the mechanisms that can help us understand invasibility, prediction, and progression, as well as on the variability, longevity, and interactions of multiple invasive species’ impacts. Thus, knowledge gained through analysis of NEON data is expected to inform sound decision‐making in unique ways for managers of systems experiencing biological invasions.

International audience; Restoration of degraded ecosystems is a global issue, particularly in rural regions where excessive loss of natural vegetation has occurred. We investigated, at both landscape and patch scales, the benefits to butterfly communities of restoration by revegetation (planting trees and shrubs), typical of many rural landscapes in south-eastern Australia. We surveyed eight pairs of landscapes (200 ha each) dominated either by remnant or restored woody vegetation, along a gradient of wooded cover. In total, 1,683 individuals of 11 butterfly species were recorded by transect counts, with the fauna dominated by four generalist species. At the landscape scale, there were similar patterns of occurrence of butterflies in remnant and restored landscapes: species richness was not related to the gradient in wooded cover, but overall abundance of butterflies increased with wooded cover. At the patch scale there was a similar richness of butterflies in revegetation and remnants (greater than in pasture), with abundance greater in remnants. Individual species showed distinctive responses to patch types (i.e. remnants, revegetation, scattered trees, pasture). In all patch types, the ground layer was dominated by exotic plants and most observations (78%) of butterflies taking nectar were from exotics. Revegetation in farmland created new wooded habitat, at least for common butterfly species, despite the study being undertaken during severe drought. Benefits of revegetation will be enhanced by actions at both the landscape scale (extent, connectivity of habitat), and patch scale (habitat quality) through promoting native ground-layer species favored for adult foraging and as larval host plants.

[Questions] European woodlands harbor at least 386 alien plant species but the factors driving local invasions remain unknown. By using a large vegetation-plot database, we asked how local richness and abundance of alien species vary by regions, elevation, climate, soil properties, human disturbance, and habitat types., [Location] Western, central and southern Europe., [Methods] We linked consolidated data from the European Vegetation Archive (16,211 plots) to a habitat classification scheme, climate, soil properties and human disturbance variables. In addition, we used 250 km × 250 km regional grid cells to test whether local patterns differ among regions. We used generalized additive models (GAMs) and quantile GAMs to explore how relative alien species richness and the sum of alien species covers per plot relate to predictors. Random Forest analyses (RFs) were employed to assess the importance of individual predictors that were not multicollinear., [Results] Relative alien species richness and the sum of alien species covers varied across regions and habitat types, with effects being more pronounced at the maximum rather than average responses. Both response variables declined with increasing elevation and distance to the nearest road or railroad and increased with the amount of sealed soil. Maxima in fitted functions matched plots from regional invasion hotspots in northwestern and central Europe. RFs accounted for 39.6% and 20.9% of the total variation in relative alien species richness and the sum of alien species covers, respectively, with region and habitat being the most important variables., [Conclusions] The importance of maximum response quantiles and the prevalence of regional hotspots point to invasion debt in European woodlands. As alien plants expand further, their species richness and abundance in woodlands will be likely driven by the shared effects of the introduction and planting history, differences in the invaded habitat types, and dispersal corridors., VW initiated this study as a part of the InvasEVe project financed by the SoMoPro II program and considers it as part of her Discovery Grant from the Canadian Natural Science and Engineering Research Council. VW's research leading to these results has acquired a financial grant from the People Program (Marie Curie Action) of the Seventh Framework Program of the EU according to REA Grant Agreement No. 291782, and it was further co-financed by the South-Moravian Region. MV and MC were supported by the Czech Science Foundation (19-28491X). PP and JP were supported by the Czech Science Foundation (19-28807X) and the Czech Academy of Sciences (RVO 67985939). JCS considers this work a contribution to his VILLUM Investigator project “Biodiversity Dynamics in a Changing World” funded by VILLUM FONDEN (grant 16549). IB and JAC were funded by the Basque Government (IT936-16). FFG was funded by the Plan Propio of the UCLM (2020-GRIN-29214)

Electrocution is one of the less known anthropogenic impacts likely a ecting the bat population. We surveyed 925 km of overhead distribution power lines that supply energy to spreading urbanized areas in Sri Lanka, recording 300 electrocuted Indian flying foxes (Pteropus giganteus). Electrocutions were recorded up to 58 km from the nearest known colony, and all of them were in urbanized areas and very close (X = 4.8 m) to the exotic fruiting trees cultivated in gardens. Predictable anthropogenic food subsidies, in the form of cultivated fruits and flowers, seem to attract flying foxes to urban habitats, which in turn become ecological traps given their high electrocution risk. However, electrocution rates greatly varied among the 352 power lines surveyed (0.00–24.6 indiv./km), being highest in power lines with four wires oriented vertically (X = 0.92 indiv./km) and almost zero in power lines with wires oriented horizontally. Therefore, the latter design should be applied to projected new power lines and old vertically oriented lines in electrocution hotspots should be substituted. Given that flying foxes are key seed dispersers and pollinators, their foraging habitat selection change toward urban habitats together with high electrocution risk not only may contribute to their population decline but also put their ecosystem services at risk

ABSTRACT OF THE DISSERTATIONInvasive Plant-Soil Feedbacks and Ecosystem Resistance and Resilience: A Comparison of Three Vegetation Types in CaliforniaBy Sara Jo DickensDoctor of Philosophy, Graduate Program in Plant BiologyUniversity of California, Riverside, December 2010Dr Edith B. Allen, ChairpersonEcosystem processes are strongly dependant on plant-soil feedbacks. The invasion of exotic plant species can result in the introduction of novel traits capable of de-coupling native plant-soil feedbacks and leading to altered nutrient cycling and availability and microbial community composition. In general the degree to which an invading species will impact the system it invades is dependant on how much it differs from plant species native to that system. However, there are examples in which invasion of an exotic plant similar to natives has led to significant alterations of ecosystem processes. The objective of this work was to examine the impacts of a single suite of exotic annual plants invading three very different vegetation types in southern California, grasslands, coastal sage scrub and chaparral. I predicted that invasion of exotic annuals would have greater impacts on shrubland systems than grasslands due to the greater disparity in plant traits between the exotic annuals and the shrub species. Comparisons of invasion impacts, however must consider factors other than vegetation type such as soil parent material, pH and soil moisture as mechanisms by which a native system may be more or less resistant to changes associated with invasion and recover following native vegetation re-establishment. In order to examine vegetation type resistance to invasion and soil resilience of these systems, I analyzed soils for total carbon and nitrogen, extractable phosphorus and nitrogen, nitrogen mineralization, soil respiration and microbial community composition using phospholipid fatty acid analysis. Long and short-term restorations were sampled concurrently with the invaded and native vegetation types to assess resilience of soils. Regardless of vegetation type nitrate was reduced by invasion, seasonality of sampling was a greater driver of microbial community composition than invasion or restoration and abiotic factors proved to be important to microbial species composition and soil nutrient availability. Individual chemical pools and functional groups of microbes responded differently in each vegetation type. However, the degree to which invading species differed from natives did not predict the level to which invasion would impact the system.

The potential value of private gardens for enhancing biodiversity has long been recognized, while, less investigated is the contribution of historical gardens. The complex history of Sicily, with its strategically central position in the Mediterranean basin, made the island an important crossroad of civilizations and also influenced the use of ornamental plants in gardens over the centuries. With the aim to investigate the biodiversity of historical gardens of Milazzo (North of Sicily), the flora of 31 gardens, dating from the late 19th to the early 20th century, were analyzed through a complete plant inventory. The gardens are localized in two areas: the first ('Piana' = 13 gardens) close to the rural area, the second ('Capo' = 18 gardens) close to the residential area. The determinants of taxonomic richness in individual gardens were carried out with the use of Shannon (H'), Simpson (D) and Evenness (J) indices. The values of the indices are, respectively for 'Capo' and 'Piana', 5.7 and 5.5 for H', 0.8 for J and 0.0046 and 0.0054 for D, and demonstrate the presence of a high biodiversity and an even distribution of individuals per species, with a few dominant species. In the 31 gardens, 529 taxa of ornamental plants were identified, belonging to 343 genera and 117 botanical families. The richness of species found in these green areas allow to consider them as "living plant collections". About 80% of the taxa were present in less than 10% of the gardens; 43.5% of species were present in a single garden. Only one species (Cycas revoluta Thunb.) was present in 87.1% of gardens to underline the species diversity.

The introduction of exotic species to new regions offers opportunities to test fundamental questions in ecology, such as the context-dependency of community structure and assembly. Annual grasslands provide a model system of a major unidirectional introduction of plant species from EuropetoNorthAmerica. WecomparedthecommunitystructureofgrasslandsintwoMediterranean regions by surveying plots in Spain and in California with similar environmental and management conditions. AllspeciesfoundinSpanishgrasslandswerenativetoSpain,andoverhalfofthem(74of 139species)areknowntohavecolonizedCalifornia. Incontrast,inCalifornia,overhalfofthespecies (52 of 95 species) were exotic species, all of them native to Spain. Nineteen species were found in multiple plots in both regions (i.e., shared species). The abundance of shared species in California was either similar to (13 species) or greater than (6 species) in Spain. In California, plants considered pests were more likely than non-pest species to have higher abundance. Co-occurring shared species tended to maintain their relative abundance in native and introduced communities, which indicates that pools of exotic species might assemble similarly at home and away. These findings provide interestinginsightsintocommunityassemblyinnovelecosystems. Theyalsohighlightanexampleof startling global and local floristic homogenization

Nowadays forests, which were formerly considered resistant to invasion due to its shady understories, are been transformed to invaded landscapes. Thus, the aim of this study was to evaluate the regeneration of native woody species in Ligustrum lucidum invaded woodlands. In addition, we aim to identify the main environmental differences between the native and invaded woodlands and evaluate the effect of those conditions in the regeneration phase of dominant native woody species. Finally, we analyze how is the emergence and survival of the exotic species in relation to that exhibited by native species in both environmental situations. For this, we performed a seed addition experiment placing three native woody species (Celtis ehrenbergiana, Lithraea molleoides, Vachellia caven) and the dominant exotic (L. lucidum) in native and invaded woodlands of the Chaco mountains, central Argentina. Also, we performed a laboratory experiment simulating the differences in light recorded at the field (main abiotic difference between both woodland types). Our field experiment indicated that, if seeds are actively added, the percentage of seedlings emergence of native species could be similar in invaded and native woodlands. However, we observed a trend of lower seedling survival after winter within the exotic monospecific stands, which was significant only for the native species C. ehrenbergiana. We suggest that this constraint could be partly related to the shadier conditions imposed by L. lucidum, since this is the major environmental change within the invaded woodlands in comparison with native ones. Consistently, the experimental simulation showed that the increased in shade reduced the overall growth of seedlings. As was mostly observed in temperate biome, our study in a subtropical seasonally dry region indicates that invaded areas may not affect the emergence stage but limit the survival of seedlings. Among the native species, C. ehrenbergiana seems to be the most suitable species to start restoration, showing the highest performance throughout the year. Combined actions of seed addition and canopy opening might counteract the abiotic constraint and contribute to restoration success of this invaded landscape. Fil: Ferreras, Ana Elisa. 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: Whitworth Hulse, Juan Ignacio. 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: Tecco, Paula Andrea. 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: Marcora, Paula Inés. 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: Funes, Guillermo. 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

Hiraoka is the created wetland that was constructed in 2000 in an urban park in Sapporo City. We introduced fen and bog plants and monitored the hydrochemical conditions and species assemblage composition four times during the 16 years after construction (YAC). The species richness indices of total, exotics, and annuals resembled those of the target fens within 11 YAC, but the species assemblages did not match the target fens even after 16 YAC, showing that species richness is a less effective way to measure success. The 0.1 m high artificial hummocks enhanced species richness 1.3 to 1.4 times more than the surrounding hollows and increased variety within species assemblages (although these hummocks collapsed before16 YAC). Water level from ground surface (WL) were stable at around 0.00 to +0.05 m, except during several-days floods, when a maximum WL of +0.4 to +0.5 m. Hydrological conditions were, therefore, similar to those natural fens nearby. Mean pH values (min and max) decreased from 6.9 (5.5–9.3) in 1 YAC to 6.2 (5.7–6.9) in 16 YAC and approached those of natural fens. The mean electrical conductivity (166–196 μS cm - 1 ) and concentrations of major minerals (Ca2+, Mg2+, and K+) were consistently higher than those of Japanese fens, but dissolved phosphorus (0.00–0.04 mg l−1) and nitrogen (0.12–0.48 mg l−1) were lower. The trajectory of species assemblages quickly approached the target fen at least 5 YAC, but then changed between 5 and 11 YAC, before stagnating. Since mineral content in Hiraoka was near the lower limit of calcareous rich-fens, abundant minerals would be less effective in changing the species assemblage compositions. Due to the dominance of eight initially introduced fen species, the trajectory turned in a different direction. Species assemblages stagnated between initial and target communities before 16 YAC, since the five fen dominants introduced at 8 to 9 YAC had not yet dominated. Accordingly, initial introductions, including species combinations of target fen, can shorten the time required to achieve natural fens. At 16 YAC, large emerged macrophytes did not dominate and did not competitively exclude fen species, probably because the water was oligotrophic and the wetland design did not include open water.

Alien plant invasions are a major component of global change, and can severely threaten local floras and global biodiversity. A striking pattern of invasive floras is that many of the world’s worst invasive plants are clonal species. However, it is still unclear whether invasive clonal plant species are in general competitively superior over native clonal plant species and whether this pattern can be affected by environmental conditions. To test whether nitrogen (N) availability and suppression of enemies can alter the competitive outcome between invasive alien and resident native clonal plants, we selected five pairs of invasive alien and co-occurring native clonal plant species in China. We grew them both in monocultures (i.e. with intraspecific competition) and in two-species mixtures (i.e. with interspecific competition) with or without N addition, and with or without suppression of enemies (using insecticide and fungicide application). Overall, invasive alien clonal plants produced significantly more biomass than native clonal plants, and took more advantage of N addition. Invasive clonal plants tended to grow better with interspecific than with intraspecific competition, whereas the reverse was true for native clonal plants. This species-origin-by-competition interaction, however, was weaker with than without N addition. Without enemy suppression, native clonal plants experienced more leaf damage than invasive aliens when they grew in interspecific competition with each other, but only in the absence of N addition. Nevertheless, enemy suppression benefited growth of invasive alien and native clonal plants to similar degrees. Our results show that already under strongly N-limited conditions, invasive clonal plants in China are competitively superior over natives, and that this competitive superiority of invasive clonal plants becomes even stronger after N addition. This implies that the ongoing eutrophication of many habitats is likely to further stimulate invasions by clonal plants.

Exotic hydrophytes are often considered as aquatic weeds, especially when forming dense mats on an originally poorly colonized environment. While management efforts and research are focused on the control and on the impacts of aquatic weeds on biodiversity, their influence on shallow lakes’ biogeochemical cycles is still unwell explored. The aim of the present study is to understand whether invasive aquatic plants may affect the biogeochemistry of shallow lakes and act as ecosystem engineers. We performed a multi-year investigation (2013–2015) of dissolved biogeochemical parameters in an oligo-mesotrophic shallow lake of south-west of France (Lacanau Lake), where wind-sheltered bays are colonized by dense mats of exotic Egeria densa Planch. and Lagarosiphon major (Ridl.) Moss. We collected seasonal samples at densely vegetated and plant-free areas, in order to extrapolate and quantify the role of the presence of invasive plants on the biogeochemistry, at the macrophyte stand scale and at the lake scale. Results revealed that elevated plant biomass triggers oxygen (O2), dissolved inorganic carbon (DIC) and nitrogen (DIN) stratification, with hypoxia events frequently occurring at the bottom of the water column. Within plants bed, elevated respiration rates generated important amounts of carbon dioxide (CO2), methane (CH4) and ammonium (NH4+). The balance between benthic nutrients regeneration and fixation into biomass results strictly connected to the seasonal lifecycle of the plants. Indeed, during summer, DIC and DIN regenerated from the sediment are quickly fixed into plant biomass and sustain elevated growth rates. On the opposite, in spring and autumn, bacterial and plant respiration overcome nutrients fixation, resulting in an excess of nutrients in the water and in the increase of carbon emission toward the atmosphere. Our study suggests that aquatic weeds may perform as ecosystem engineers, by negatively affecting local oxygenation and by stimulating nutrients regeneration.

Exotic species introductions are a global phenomenon and protected areas are susceptible to them. Understanding the drivers of exotic species richness is vital for prioritizing natural resource management, particularly in developing countries with limited resources. We analyzed the influence of coarse resolution factors on exotic species richness (plants, mammals, and birds) in Argentina’s National Parks System. We collected data on native species richness, year of park formation, park area, region, elevation range, number of rivers crossing area boundaries, roads entering area, mean annual rainfall, mean annual temperature, mean annual number of visitors, and Human Influence Index within and surrounding each park. We compiled 1,688 exotic records in 36 protected areas: 83% plants and 17% animals (9.5% mammals, 5.5% birds, 1.5% fishes, 0% amphibians, 0% reptiles). The five parks with the most exotic species (all taxa combined) were in north Patagonia. Exotic grasses were the most common exotic plants, and within animals, lagomorphs and feral ungulates were remarkably widespread. Exotic plant richness was mostly influenced by temperature and native plant richness, while exotic mammal and bird richness was driven mostly by anthropogenic variables, with models explaining 36–45% of data deviance. Most variables that positively influenced exotic taxa were indirectly related to an increase in spatial heterogeneity (natural or anthropogenic), suggesting greater niche space variability as facilitators of exotic richness increase. Additional data are needed to further investigate the patterns and mechanisms of exotic species richness in protected areas, which will help to prioritize the greatest needs of monitoring and management.

Anthropogenic disturbance can alter the structure of ecological networks in ways that have population consequences. For example, bird-plant networks in forests surrounded by urban land were more likely to be dominated by strong interactions (i.e., less even in strength) than networks in rural landscapes, and these asymmetric interactions depressed avian nest survival. Based on this prior research, we hypothesized that invasion of urban habitats by exotic plants was the underlying mechanism driving changes in network structure. We tested this hypothesis using an in situ experiment where exotic Amur honeysuckle (Lonicera maackii) was removed from replicated 2-ha forest plots and compared bird-plant networks among urban removal forests, urban control forests dominated by honeysuckle, and rural forests with little honeysuckle. From 2005 to 2011, we surveyed densities of understory-nesting birds and nest predators, recorded information about nest location, and monitored nest survival. For each year and site network, we calculated evenness of interaction strengths. Despite post-removal vegetation resembling that in rural forests, removal of exotic honeysuckle did not restore network structure. Evenness of interactions between birds and plants was greatest in rural forests and least in urban control plots. Nest survival increased with evenness across all sites, but the relationship was strongest within urban removal plots, which had the lowest overall nest survival rates. Even though invasion by honeysuckle was a plausible driver of urban-associated network shifts in previous studies, the experimental removal suggested that factors other than invasion were responsible for network changes or that our system experienced hysteresis or time lags. Our study suggests that restoration of ecological networks may be more challenging than anticipated.

Since neophytes can become invasive in the future, untangling their ecological preferences is of paramount importance, especially in urban areas where they represent a substantial proportion of the local flora. Studies exploring alien species assemblages in urban environments are however scarce. This study aims to unravel alien plant species preferences for five urban land uses (densely built-up areas, open built-up areas, industrial areas, broadleaved urban forests, and agricultural areas and small landscape elements). We took the city of Brussels as a model, in which we recorded all vascular species growing spontaneously in grid cells of 1 km2. We tested two different ways of classifying the 1-km2 cells: (1) We simply associated each cell with its dominant land cover; (2) We used a fuzzy approach for which the degree of association of a given cell to a given land cover depended on the proportion of that land cover within the cell. For both classification methods, we calculated the indicator species of the resulting land cover types based on alien species only. The crisp and fuzzy classifications identified 33 and 49 species, respectively, with a clear preference for some urban land use types (from a total of 129 alien plant species analyzed). Results showed that urban land use types having apparently similar environmental conditions can actually harbor different neophyte assemblages. Fine-tuning the categorization of urban environments in future ecological studies is therefore important for understanding spatial patterns of alien species occurrence.

Analyses deriving insights from 23 research sites across the northeastern and east central US reveals that white-tailed deer lower native plant diversity and increase the fraction of the plant community made up of non-native species. Particularly, deer increase the abundance of the invasive plants garlic mustard and Japanese stiltgrass. Deer are known to avoid eating these species in favour of more palatable ones, thereby indirectly facilitating the success of the non-native invasives. Managing deer abundance has implications for forest plant communities. By maintaining lower deer densities, native plants likely will be better sustained and invasions of unpalatable non-native plants limited., Herbivores can profoundly influence plant species assembly, including plant invasion, and resulting community composition. Population increases of native herbivores, e.g. white-tailed deer (Odocoileus virginianus), combined with burgeoning plant invasions raise concerns for native plant diversity and forest regeneration. While individual researchers typically test for the impact of deer on plant invasion at a few sites, the overarching influence of deer on plant invasion across regional scales is unclear. We tested the effects of deer on the abundance and diversity of introduced and native herbaceous and woody plants across 23 white-tailed deer research sites distributed across the east-central and north-eastern USA and representing a wide range of deer densities and invasive plant abundance and identity. Deer access/exclusion or deer population density did not affect introduced plant richness or community-level abundance. Native and total plant species richness, abundance (cover and stem density) and Shannon diversity were lower in deer-access vs. deer-exclusion plots. Among deer-access plots, native species richness, native and total cover, and Shannon diversity (cover) declined as deer density increased. Deer access increased the proportion of introduced species cover (but not of species richness or stem density). As deer density increased, the proportion of introduced species richness, cover and stem density all increased. Because absolute abundance of introduced plants was unaffected by deer, the increase in proportion of introduced plant abundance is likely an indirect effect of deer reducing native cover. Indicator species analysis revealed that deer access favoured three introduced plant species, including Alliaria petiolata and Microstegium vimineum, as well as four native plant species. In contrast, deer exclusion favoured three introduced plant species, including Lonicera japonica and Rosa multiflora, and 15 native plant species. Overall, native deer reduced community diversity, lowering native plant richness and abundance, and benefited certain invasive plants, suggesting pervasive impacts of this keystone herbivore on plant community composition and ecosystem services in native forests across broad swathes of the eastern USA.

Despite many studies have documented that fragmentation facilitates biological invasions, studies performed in different taxonomic groups have observed contrasting patterns. Unfortunately, the use of different ecosystems and fragmentation metrics among studies does not allow assessing the generality of the effect of fragmentation on invasion among different taxa. Studies evaluating the simultaneous responses of exotic species from different taxonomic groups to the same fragmentation patterns may help to assess generality of this relationship. Temperate forests in coastal central Chile are largely a suite of fragments of different sizes surrounded mainly (but not exclusively) by Pinus radiata plantations. Here, we evaluated exotic species richness of vascular plants, insects, mammals and birds in the coastal Maulino forest in a continuous native forest, fragments of native forest and Pinus radiata plantations. Species richness of exotic species of all taxa varied similarly across landscape units. Plantations presented the highest number of exotic species, followed by fragments and finally the continuous forest. In addition, regarding all exotic species, landscape units showed a nested pattern in which most exotic species present in the continuous forest were also present in fragments; and most species present in fragments were present in the pine plantation as well. Our results suggest that fragmentation may affect invasion of different taxa in a similar way, and that continuous forests may efficiently resist invasion. Our results also suggest that given that most of the native forest of south-central Chile is distributed in small fragments, it seems urgent to start an exotic species control to maintain their conservation value., A pesar de que varios estudios han observado que la fragmentación del hábitat facilita la invasión de especies exóticas, trabajos realizados en distintos taxa han observado patrones diferentes. Lamentablemente, el uso de diferentes tipos de ecosistemas y métricas de fragmentación no permite establecer la generalidad del efecto de la fragmentación en la invasión de diferentes taxa. Estudios que evalúen simultáneamente la respuesta de especies exóticas de diferentes grupos taxonómicos a los mismos patrones de fragmentación podrían ayudar a establecer la generalidad de esta relación. El bosque templado de la zona costera de Chile central está compuesto de fragmentos de diferentes tamaños rodeados principalmente (pero no exclusivamente) por plantaciones de Pinus radiata. En este trabajo se evaluó la riqueza de especies exóticas de plantas, insectos, mamíferos y aves en un bosque nativo continuo, fragmentos de bosque nativo y plantaciones de Pinus radiata. La variación de la riqueza de especies exóticas entre las unidades de paisaje fue similar entre los taxa estudiados. Las plantaciones presentaron más especies exóticas, seguido por fragmentos y, finalmente, el bosque continuo. La composición de especies exóticas presentó un patrón anidado entre las unidades de paisaje: la mayoría de las especies exóticas presentes en el bosque continuo estuvieron en los fragmentos, y la mayoría de las especies de los fragmentos estuvieron en la plantación. Los resultados sugieren que la fragmentación puede afectar la invasión de diferentes taxa similarmente, y que el bosque continuo puede resistir eficientemente la invasión. Los resultados también sugieren que debido al estado fragmentado de estos bosques nativos de Chile, parece urgente un control de especies exóticas para mantener su valor de conservación.

Las especies exóticas pueden impactar en el proceso de descomposición, ya sea de manera directa (diferencias en calidad y/o cantidad de hojarasca) o de manera indirecta (modificando las condiciones micro ambientales y la abundancia y/o actividad de descomponedores). Los objetivos de este trabajo fueron: I) comparar la descomponibilidad de las especies exóticas y nativas más abundantes de los bosques secundarios del pedemonte de la Sierra de San Javier, Tucumán, II) analizar el efecto de las condiciones micro ambientales sobre la tasa de descomposición de un sustrato común y III) evaluar el efecto del tamaño de malla de las bolsas de descomposición en la descomposición de hojarasca. Para ello incubamos hojarasca de 7 especies nativas y 7 exóticas bajo condiciones estándares durante un año y hojarasca de Populus deltoides (sustrato común) en parches de bosques secundarios nativos e invadidos por Ligustrum lucidum en bolsas con dos tamaños de malla. La pérdida de peso no fue diferente entre el conjunto de especies nativas y exóticas pero si se encontraron diferencias interespecíficas. La constante de descomposición del sustrato común fue menor en los bosques invadidos por lo que L. lucidum modificaría la composición y/o actividad de organismos descomponedores y generaría cambios en las condiciones micro ambientales que determinan la descomposición. Por otra parte, la descomposición fue mayor en bolsas con malla grande, lo cual podría deberse al acceso de macro invertebrados. Nuestros resultados sugieren la ausencia de un patrón de descomposición en el conjunto de especies nativas y exóticas y la potencial influencia que tendría L. lucidum en los factores que controlan la descomposición. Exotic species may influence the process of decomposition, either directly (through differences in the quality and/or quantity of leaf-litter) or indirectly (by altering microclimatic conditions and the abundance and/or activity of decomposers). The aims of our study were: I) to compare the decomposability of the most abundant exotic and native species in secondary forests of the Sierra de San Javier, Tucumán, II) to assess the effect of microenvironemtal conditions on the rate of decomposition of an homogeneous substrate and III) to evaluate the effect of the litterbags mesh size on the decomposition process. To do this, we incubated leaf-litter of 7 native and 7 exotic species under standard conditions for one year and also leaf-litter of Populus deltoides (homogeneous substrate) in native and invaded by Ligustrum lucidum secondary forest patches in bags with two mesh sizes. Native and exotic species did not differ in their weight loss rates, but there were interspecific differences. The decay constant of the homogeneous substrate was lower in invaded patches so it is possible that L. lucidum modify the composition and /or activity of decomposing organisms and generate changes in micro-environmental conditions. In addition, decomposition was higher in bags with larger mesh size. This pattern may be explained by the differential access of macro invertebrates. Our results suggest the absence of a pattern of decay in native and exotic species as groups, and the potential influence that L. lucidum would have over the factors controlling littler decomposition.

Invasive alien plants (IAPs) are regarded as the leading ecological threat to the recently established Garden Route National Park (GRNP) along the Cape south coast of South Africa. The extensive and long-standing presence of commercial forestry in the region has contributed substantially to the current load of IAPs in the area. The GRNP's fragmented, linear configuration and a multitude of anthropogenic and ecological disturbances in the landscape contribute to its susceptibility to alien plant invasion. In compiling a checklist of alien flora for the park, we recorded 244 species of alien plants in 77 families, of which 58% (141 species) have not been recorded for the region by the Southern African Plant Invaders Atlas. Of the GRNP alien plant species, 9% are casual aliens, 27% naturalised, 59% invasive, and 5% transformers. Among South African National Parks, the GRNP ranks second in terms of alien plant species richness and has the largest proportion of invasives and transformers for those parks where invasion status was recorded. Transformer species in the GRNP are almost exclusively tree species introduced from Australasia > 100 years ago for forestry purposes or sand stabilisation. Natural habitat within the park that is most threatened by IAPs is fynbos shrublands and riparian habitat. Our analysis indicates that the pressure of IAPs in the GRNP is escalating. Substantial and sustained management actions will be required to mitigate impacts from alien plant invasions in the GRNP. We identified species posing emerging or escalating threats that require improved control or regulation.

Even though Brazil is a mega-diverse country, many Brazilian cities prioritize exotic plants in their treescapes. Aiming to evaluate how much the treescape in Fortaleza (the fifth largest city in Brazil) is aligned with the policy of valorization of native biodiversity, we sampled street and backyard trees surrounding one of the few vegetation fragments of the city, which is an area considered a priority for conservation. We used the vegetation fragment's flora as reference to compare the potential number of local native species with the actual number of native species in the treescape of the site. To account how much of the native flora was present in the surrounding treescape, we made an inventory of the trees in streets, squares and backyards around the vegetation and compared with the native flora of the vegetation fragment. We then compared the ratio of native to exotic species and checked how many native species of the fragment were also in the surrounding treescape. Exotics were prevalent in both number of species and number of individuals, comprising 70% of the species and 86% of the individuals of public spaces, and 79% of the species and 78% of the individuals of private spaces. Only 14% of the native species of the vegetation were also represented in the treescape, and, in general, they comprehended only a few individuals. We argue that the city's treescape should be re-evaluated in order to value native plants more. Native plants in the treescape could be used as an environmental education tool to publicize native biodiversity to citizens.

Efforts have been made to understand the processes that lead to the introduction of exotic species into local pharmacopoeias. Among those efforts, the diversification hypothesis predicts that exotic plants are introduced in local medical systems to amplify the repertoire of knowledge related to the treatment of diseases, filling blanks that were not occupied by native species. Based on such hypothesis, this study aimed to contribute to this discussion using the context of local Brazilian populations. We performed a systematic review of Brazilian studies up to 2011 involving medicinal plants, excluding those studies that presented a high risk of bias (because of sampling or plant identification problems). An analysis of similarities (ANOSIM) was conducted in different scales to test for differences in the repertoire of therapeutic indications treated using native and exotic species. We have found that although there is some overlap between native and exotic plants regarding their therapeutic indications and the body systems (BSs) that they treat, there are clear gaps present, that is, there are therapeutic indications and BSs treated that are exclusive to exotic species. This scenario enables the postulation of two alternative unfoldings of the diversification hypothesis, namely, (1) exotic species are initially introduced to fill gaps and undergo subsequent expansion of their use for medical purposes already addressed using native species and (2) exotic species are initially introduced to address problems already addressed using native species to diversify the repertoire of medicinal plants and to increase the resilience of medical systems. The reasons why exotic species may have a competitive advantage over the native ones, the implications of the introduction of exotic species for the resilience of medical systems, and the contexts in which autochthonous plants can gain strength to remain in pharmacopoeias are also discussed. Fil: Muniz de Medeiros, Patrícia. Universidade Federal de Alagoas; Brasil Fil: Ferreira Junior, Washington Soares. Universidade Federal de Pernambuco; Brasil Fil: Ramos, Marcelo Alves. Universidade Federal de Pernambuco; Brasil Fil: Da Silva, Taline Cristina. Universidade Federal de Alagoas; Brasil Fil: Ladio, Ana Haydee. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Albuquerque, Ulysses Paulino. Universidade Federal de Pernambuco; Brasil

Confertobasidium olivaceoalbum, a rare corticioid fungus, is recorded for the first time on wood of Eucalyptus globulus in Italy. Since this species has been recorded only on coniferous wood, this finding adds new information to the ecology, geographic distribution and molecular data of corticioid fungi.

Given the potential ecological impacts of invasive species, removal of alien plants has become an important management challenge and a high priority for environmental managers. To consider that a removal effort has been successful requires both, the effective elimination of alien plants and the restoration of the native plant community back to its historical composition and function. We present a conceptual framework based on observational and experimental data that compares invaded, non-invaded and removal sites to quantify invaders’ impacts and native plant recover after their removal. We also conduct a meta-analysis to quantitatively evaluate the impacts of plant invaders and the consequences of their removal on the native plant community, across a variety of ecosystems around the world. Our results that invasion by alien plants is responsible for a local decline in native species richness and abundance. Our analysis also provides evidence that after removal, the native vegetation has the potential to recover to a pre-invasion target state. Our review reveal that observational and experimental approaches are rarely used in concert, and that reference sites are scarcely employed to assess native species recovery after removal. However, we believe that comparing invaded, non-invaded and removal sites offer the opportunity to obtain scientific information with relevance for management.

Recovery of indigenous species subsequent to the clearing of invasive alien plants (IAPs) is crucial for ecosystem recovery to occur. However, cleared sites are often just left in the hope that revegetation will occur naturally. In riparian areas of Kruger National Park (KNP), the Working for Water (WfW) Programme has cleared IAPs on a regular basis, but little post-clearance monitoring has taken place. Thus investigating short-term effects of IAPs and IAP clearing on plant community diversity and vegetation recovery provided an ideal opportunity to assess feasible targets of natural ecosystem recovery in similar areas. Vegetation was sampled from twelve transects along the Sabie River in and adjacent to the KNP, before (March/April 2006) and after (March 2007) the annual clearing of IAPs by WfW. Rarefied species richness, alpha diversity and evenness of distribution of species all declined with increasing density of IAPs (Pb 0.05). There was a mean reduction in IAP density of 80% (S.E ± 6%) (P = 0.002) through the clearing by WfW. After clearing of IAPs, indigenous vegetation densities increased, with herbaceous growth forms showing the largest increase in transects that were previously heavily invaded. Thus, in this system, which is relatively undisturbed by human activities, initial recovery of indigenous vegetation can occur without further restorative interventions. This process is more than likely aided by the continuous clearing of IAPs by WfW as this acts to deplete alien seed banks and maintain IAPs at acceptable and manageable levels. © 2008 SAAB. Published by Elsevier B.V. All rights reserved.

The integration of invasive species into native food webs represent multifarious dynamics of ecological and evolutionary processes. We document incorporation of Prunus serotina (black cherry) into native insect food webs. We find that P. serotina harbours a herbivore community less dense but more diverse than its native relative, P. padus (bird cherry), with similar proportions of specialists and generalists. While herbivory on P. padus remained stable over the past century, that on P. serotina gradually doubled. We show that P. serotina may have evolved changes in investment in cyanogenic glycosides compared with its native range. In the leaf beetle Gonioctena quinquepunctata, recently shifted from native Sorbus aucuparia to P. serotina, we find divergent host preferences on Sorbus- versus Prunus-derived populations, and weak host-specific differentiation among 380 individuals genotyped for 119 SNP loci. We conclude that evolutionary processes may generate a specialized herbivore community on an invasive plant, allowing prognoses of reduced invasiveness over time. On the basis of the results presented here, we would like to caution that manual control might have the adverse effect of a slowing down of processes of adaptation, and a delay in the decline of the invasive character of P. serotina.

Aim: To investigate the role of alien plants in mutualistic plant-hummingbird networks, assessing the importance of species traits, floral abundance and insularity on alien plant integration. Location: Mainland and insular Americas. Methods: We used species-level network indices to assess the role of alien plants in 21 quantitative plant-hummingbird networks where alien plants occur. We then evaluated whether plant traits, including previous adaptations to bird pollination, and insularity predict these network roles. Additionally, for a subset of networks for which floral abundance data were available, we tested whether this relates to network roles. Finally, we tested the association between hummingbird traits and the probability of interaction with alien plants across the networks. Results: Within the 21 networks, we identified 32 alien plant species and 352 native plant species. On average, alien plant species attracted more hummingbird species (i.e. aliens had a higher degree) and had a higher proportion of interactions across their hummingbird visitors than native plants (i.e. aliens had a higher species strength). At the same time, an average alien plant was visited more exclusively by certain hummingbird species (i.e. had a higher level of complementary specialization). Large alien plants and those occurring on islands had more evenly distributed interactions, thereby acting as connectors. Other evaluated plant traits and floral abundance were unimportant predictors of network roles. Short-billed hummingbirds had higher probability of including alien plants in their interactions than long-billed species. Main conclusions: Once incorporated into plant-hummingbird networks, alien plants appear strongly integrated and, thus, may have a large influence on network dynamics. Plant traits and floral abundance were generally poor predictors of how well alien species are integrated. Short-billed hummingbirds, often characterized as functionally generalized pollinators, facilitate the integration of alien plants. Our results show that plant-hummingbird networks are open for invasion. © 2016 John Wiley & Sons Ltd.

1. As a result of global warming, species may spread into previously cool regions. Species that disperse faster than their natural enemies may become released from top-down control. We investigated whether plants originating from southern Europe and recently established in north-western Europe experience less soil pathogen effects than native species. 2. We selected three plant species originating from southern Europe that have immigrated into the Netherlands and three similar native Dutch species. All six plant species were grown in sterilized soils with a soil inoculum collected from the rhizospheres of field populations. As a control we grew a series of all six plant species with a sterilized rhizosphere inoculum. 3. We harvested the plants, added the conditioned soil to sterilized soil and grew a second generation of all six plant species in order to test for each plant pair feedback effects from the conditioned soil communities to conspecifics and heterospecifics. 4. The effect of the soil community is dependent on plant species, and is dependent on soil fertility in only one of the three pairs. 5. Soil conditioning caused less biomass reduction to exotic plant species than to native species, suggesting that exotic immigrants are less exposed to soil pathogens than similar native plant species. 6. Our results suggest that plant species that expand their range as a result of climate change may become released from soil pathogenic activity. Whether the exotics are released from soil pathogens, or whether they experience enhanced benefit from mutualistic symbionts remains to be studied. We conclude that range expansion may result in enemy release patterns that are similar to artificially introduced invasive exotic plant species. 7. The escape from enemies through range shifts changes key biotic interactions and complicates predictions of future distribution and dominance.

A comprehensive checklist of Sesotho names of both indigenous and exotic food plants is presented, based on a literature survey and the first author's experience. The list includes the scientific names. English common names and parts of the plant that are used. Where possible, the origin or meaning of the Sesotho names is given. Exotic edible plants for which the English common names are in general use have been excluded. The list includes 164 indigenous and 39 names of exotic species.

Alien plants may be reproductively limited in exotic habitats because of a lack of mutualistic pollinators. However, if plants are adequately served by generalist pollinators, successful reproduction, naturalisation and expansion into exotic habitats may occur. Rhododendron ponticum is very successful, ecologically damaging invasive plant in Britain and Ireland, but is in decline in its native Iberian habitat. It spreads locally by sending out lateral branches, but for longer distance dispersal it relies on sexually produced seeds. Little is known about R. ponticum's pollination ecology and breeding biology in invaded habitats. We examined the flower-visiting communities and maternal reproductive success of R. ponticum in native populations in southern Spain and in exotic ones in Ireland. R. ponticum in flowers are visited by various generalist (polylectic) pollinator species in both native and exotic habitats. Although different species visited flowers in Ireland and Spain, the flower visitation rate was not significantly different. Insects foraging on R. ponticum in Spain carried less R. ponticum pollen than their Irish counterparts, and carried fewer pollen types. Fruit production per inflorescence varied greatly within all populations but was significantly correlated with visitation at the population level. Nectar was significantly depleted by insects in some exotic populations, suggesting that this invasive species is providing a floral resource for native insects in some parts of Ireland. The generality of the pollination system may be factor contributing to R.ponticum's success in exotic habitats. Ministerio de Ciencia y Tecnología PB98-1144

Exotic plants have the capacity to establish positive plant-soil feedbacks facilitating invader persistence often at the cost of native plant species success. We compared the plant communities, soil chemical and microbial communities and nutrient turnover rates between invaded and restored plots in inland and coastal grasslands. Greater extractable N, slower N cycling rates and differing microbial community composition resulted from restoration. These differences indicate that grassland soils are responsive to vegetation change, and therefore not resistant to invasion-caused feedbacks. It also suggests these soils are resilient to invasion and may be capable of recovery following vegetative restoration., Grasslands have a long history of invasion by exotic annuals, which may alter microbial communities and nutrient cycling through changes in litter quality and biomass turnover rates. We compared plant community composition, soil chemical and microbial community composition, potential soil respiration and nitrogen (N) turnover rates between invaded and restored plots in inland and coastal grasslands. Restoration increased microbial biomass and fungal : bacterial (F : B) ratios, but sampling season had a greater influence on the F : B ratio than did restoration. Microbial community composition assessed by phospholipid fatty acid was altered by restoration, but also varied by season and by site. Total soil carbon (C) and N and potential soil respiration did not differ between treatments, but N mineralization decreased while extractable nitrate and nitrification and N immobilization rate increased in restored compared with unrestored sites. The differences in soil chemistry and microbial community composition between unrestored and restored sites indicate that these soils are responsive, and therefore not resistant to feedbacks caused by changes in vegetation type. The resilience, or recovery, of these soils is difficult to assess in the absence of uninvaded control grasslands. However, the rapid changes in microbial and N cycling characteristics following removal of invasives in both grassland sites suggest that the soils are resilient to invasion. The lack of change in total C and N pools may provide a buffer that promotes resilience of labile pools and microbial community structure.

Made available in DSpace on 2015-03-18T15:56:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-11-01Bitstream added on 2015-03-18T16:28:24Z : No. of bitstreams: 1 WOS000345597500010.pdf: 451042 bytes, checksum: 6b6f290c165b04f7d23359c0fc103564 (MD5) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) In this study, we performed a scientometric analysis of published scientific papers on the biological invasion of macrophytes in freshwater ecosystems to assess the main trends and gaps in research concerning this group of organisms. The analysis showed that publications on invasive macrophytes increased exponentially in the last decade. However, the activity index (a comparison of the quantitative trends of invasive macrophytes in relation to all of the papers on macrophytes) indicated that invasive macrophytes have not been consistently studied more than other topics in the field of limnology over the last decade. The most studied macrophyte species were Myriophyllum spicatum, Hydrilla verticillata, Phragmites australis and Eichhornia crassipes. Certain gaps were related to the limited number of studies on the important species threatening tropical ecosystems, under-representation of investigations on the impacts of invasive macrophytes on fish and lack of studies associating macrophytes with microorganisms (bacteria and fungi). Studies that encompassed several levels of biological complexity were also scarce, indicating that the studies were fragmented at specific levels. Finally, there was a clear geographical bias, with fewer studies occurring in Neotropical and Afrotropical regions. Identification of these gaps may be useful for addressing future studies that might help evaluate the causes of invasion by macrophytes and the impacts of such invasions on freshwater ecosystems. Univ Estadual Maringa, Dept Biol, Nucleo Pesquisas Limnol Ictiol & Aquicultura, BR-87020900 Maringa, Parana, Brazil Univ Estadual Paulista, Programa Posgrad Aquicultura, BR-14884900 Jaboticabal, SP, Brazil Univ Estadual Paulista, Programa Posgrad Aquicultura, BR-14884900 Jaboticabal, SP, Brazil FAPESP: 12/21517-9

The introduction of a species may alter ecological processes of native populations, such as pollination and dispersal patterns, leading to changes in population structure. When the introduced and the native species are congeners, interference in pollination can also lead to hybridization. We aimed to understand the ecological aspects of Euterpe oleracea introduction in the Atlantic forest and the possible consequences for the conservation of the native congener Euterpe edulis. We analysed the population structure of palm populations, including hybrids, and observed the interaction with frugivorous birds of both palm species after E. oleracea introduction. We observed that E. edulis had significantly lower density and a smaller number of seedlings when occurring with E. oleracea. Native and introduced Euterpe species shared nine frugivorous bird species. E. oleracea and hybrids had dispersed outside the original planting area. Consequently, the risks of introduction of E. oleracea may mostly be related to the disruption of interactions between E. edulis and frugivorous birds and the spontaneous production of hybrids. Finally, the cultivation of E. oleracea and hybrids in Atlantic rainforest could affect the conservation of the already endangered E. edulis. Resumo A introdução de uma espécie pode alterar processos ecológicos de populações nativas, tais como padrões de polinização e dispersão, levando a mudanças na estrutura populacional. Quando espécies introduzidas e nativas são congêneres, a interferência na polinização pode levar também à hibridização. Nossos objetivos foram entender os aspectos ecológicos da introdução de Euterpe oleracea na Floresta Atlântica e as possíveis consequências sobre a conservação da congênere nativa Euterpe edulis. Para isso, analisamos a estrutura populacional, incluindo híbridos, e observamos a interação de aves frugívoras com ambas as espécies de palmeira após a introdução de E. oleracea. Observamos que E. edulis apresentou densidade total e número de plântulas menores quando coocorrente com E. oleracea. As palmeiras congenéricas compartilharam nove espécies de aves frugívoras. E. oleracea e híbridos foram dispersos além da área original de plantio. Consequentemente, os riscos da introdução de E. oleracea podem estar principalmente relacionados com o possível deslocamento de interações entre E. edulis e aves frugívoras e com a produção de híbridos. Desta forma, o cultivo de E. oleracea e híbridos podem afetar a conservação da já ameaçada E. edulis.

1. Native herbivores can establish novel interactions with alien plants after invasion. Nevertheless, it is unclear whether these new associations are quantitatively significant compared to the assemblages with native flora under natural conditions. 2. Herbivores associated with two exotic plants, namely Senecio inaequidens and S. pterophorus, and two coexisting natives, namely S. vulgaris and S. lividus, were surveyed in a replicated long-term field study to ascertain whether the plant herbivore assemblages in mixed communities are related to plant novelty and insect diet breadth. 3. Native herbivores used exotic Senecio as their host plants. Of the 19 species of Lepidoptera, Diptera, and Hemiptera found in this survey, 14 were associated with the exotic Senecio plants. Most of these species were polyphagous, yet we found a higher number of individuals with a narrow diet breadth, which is contrary to the assumption that host switching mainly occurs in generalist herbivores. 4. The Senecio specialist Sphenella marginata (Diptera: Tephritidae) was the most abundant and widely distributed insect species (ca. 80% of the identified specimens). Sphenella was associated with S. lividus, S. vulgaris and S. inaequidens and was not found on S. pterophorus. The presence of native plant congeners in the invaded community did not ensure an instantaneous ecological fitting between insects and alien plants. 5. We conclude that novel associations between native herbivores and introduced Senecio plants are common under natural conditions. Plant novelty is, however, not the only predictor of herbivore abundance due to the complexity of natural conditions.