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Questions: Do functional and phylogenetic diversity vary along a natural metal gradient? Do resources acquisition and metal tolerance‐related traits show the same patterns of variation? Is the ability to grow on metal‐enriched soil phylogenetically conserved or the result of functional convergence? Location: Fungurume V hill (10°37′03″ S, 26°17′22″ E), Upper Katanga, Democratic Republic of Congo. Methods: In 21 communities along a natural copper gradient, we quantified the variation of species richness and turnover as well as the phylogenetic diversity. We assessed the variation of three univariate functional indices — community‐weighted mean, functional richness and functional dispersion — for ten functional traits related to resources acquisition, conservation, dispersal and metal tolerance strategy. Results and Conclusions: Along a gradient of increasing soil Cu concentration, we found a decrease in species number and a strong species turnover. On metal‐poor soils, phylogenetic clustering and overdispersion of functional traits indicated selection for certain clades (e.g. Fabaceae) with many different trait combinations suggesting niche partitioning. On metal‐enriched soils, contrary to expectations, we found functional convergence towards trait values associated with rapid resource use, lower stature and smaller seeds in several clades. Conversely, metal tolerance strategy showed a clear overdispersion on metal‐rich soils reflecting the presence of several strategies to cope with the excess of metal in the soil. This suggests that some extreme toxicity gradients, such as this one, do not always impose strong functional convergence towards a stress tolerance strategy, as is often assumed. [ABSTRACT FROM AUTHOR]

Questions: Small islands are outstanding model systems to study community assembly. Due to harsher environmental conditions on smaller islands compared to larger ones, environmental filtering may preclude some species, potentially resulting in island size‐dependent species pools. We tested whether the species pool size follows a similar species–area relationship as the observed richness. This can provide new insight into community assembly processes and the elusive small‐island effect (SIE), which states that species richness on smaller islands is less dependent on area than on larger islands. Location: Raja Ampat Archipelago, Indonesia. Methods: We studied the woody vegetation on sixty small islands ranging from 3 m2 to 11,806 m2. For each recorded species, we estimated its area requirements and compared them against random colonization models. We developed a novel method to calculate probabilistic species pools for each island. We compared different species–area models for observed species richness and our index of species pool size to test whether the SIE results from differences in species pool size. Results: We found that most species were restricted to islands significantly larger than expected from random colonization. The occurrence probability of all species increased with island size, indicating a lack of species that are specialized to the conditions on small islands. We found a SIE in observed species richness, but not in species pool size. Conclusion: Woody plants in the studied island system have specific requirements that are linked to island area and determine island‐specific species pools. Lower community completeness on smaller islands compared to larger ones indicated that the SIE is shaped by local limiting processes that have no impact on the species pool, but control how much of it is realized on an island. Together, these results clearly indicate non‐random plant community assembly on small islands. [ABSTRACT FROM AUTHOR]

AlienScenarios, a three-year project starting in March 2019, will evaluate for the first time the range of plausible futures of biological invasions for the 21st century. AlienScenarios consists of seven project partners and seven integrated complementary subprojects. We will develop the qualitative narratives for plausible futures of global alien species richness and impacts in the 21st century - the Alien Species Narratives (ASNs). The ASNs further serve as overarching concept to parameterize quantitative models of global, continental and regional futures of biological invasions. We will also establish the first global mechanistic invasion model considering major processes of biological invasions such as source pools, driver dynamics and establishment rates. Further, we will assess the impacts of invasive alien species (IAS) in terms of economic costs according to the different ASNs. In addition, we will assess the consequences of different levels of implementation of the European Union Regulation on IAS. Providing some more detailed regional information, we will analyse changes of the functional composition of communities in mountain regions under different scenario storylines and will extend the analyses to the Global South using Panama as a country-level case study. Finally, the results of the other WPs will be synthesized, and the approach and results of AlienScenarios will be discussed with and communicated to stakeholders and the wider community. AlienScenarios will provide crucially needed insights for pro-active alien species management and policy. It will thus make an important contribution to global assessments and projections of biodiversity and ecosystem services, as well as regional policies (e.g. EU regulation on IAS). [ABSTRACT FROM AUTHOR]

AlienScenarios, a three-year project starting in March 2019, will evaluate for the first time the range of plausible futures of biological invasions for the 21st century. AlienScenarios consists of seven project partners and seven integrated complementary subprojects. We will develop the qualitative narratives for plausible futures of global alien species richness and impacts in the 21st century -- the Alien Species Narratives (ASNs). The ASNs further serve as overarching concept to parameterize quantitative models of global, continental and regional futures of biological invasions. We will also establish the first global mechanistic invasion model considering major processes of biological invasions such as source pools, driver dynamics and establishment rates. Further, we will assess the impacts of invasive alien species (IAS) in terms of economic costs according to the different ASNs. In addition, we will assess the consequences of different levels of implementation of the European Union Regulation on IAS. Providing some more detailed regional information, we will analyse changes of the functional composition of communities in mountain regions under different scenario storylines and will extend the analyses to the Global South using Panama as a country-level case study. Finally, the results of the other WPs will be synthesized, and the approach and results of AlienScenarios will be discussed with and communicated to stakeholders and the wider community. AlienScenarios will provide crucially needed insights for pro-active alien species management and policy. It will thus make an important contribution to global assessments and projections of biodiversity and ecosystem services, as well as regional policies (e.g. EU regulation on IAS). [ABSTRACT FROM AUTHOR]

Forests with higher tree diversity are often assumed to be more resistant to insect herbivores but whether this effect depends on climatic conditions is so far poorly understood. In particular, a forest’s resistance to herbivory may depend on mean annual temperature (MAT) as a key driver of plant and insect phenology. We carried out a global meta-analysis on regression coefficients between tree diversity and four aspects of insect herbivory, namely herbivore damage, abundance, incidence rate and species richness. To test for a potential shift of tree diversity effects along a global gradient of MAT we applied mixed-effects models and estimated grand mean effect sizes and the influence of MAT, experimental vs. observational studies and herbivores diet breadth. There was no overall effect of tree diversity on the pooled effect sizes of insect herbivore damage, abundance and incidence rate. However, when analysed separately, we found positive grand mean effect sizes for herbivore abundance and species richness. For herbivore damage and incidence rate we found a significant but opposing shift along a gradient of MAT indicating that with increasing MAT diversity effects on herbivore damage tend towards associational resistance whereas diversity effects on incidence rates tend towards associational susceptibility. Our results contradict previous meta-analyses reporting overall associational resistance to insect herbivores in mixed forests. Instead, we report that tree diversity effects on insect herbivores can follow a biogeographic pattern calling for further in-depth studies in this field. [ABSTRACT FROM AUTHOR]

Theory suggests that the structure of evolutionary history represented in a species community may affect its functioning, but phylogenetic diversity metrics do not allow for the identification of major differences in this structure. Here we propose a new metric, ELDERness (for Evolutionary Legacy of DivERsity) to estimate evolutionary branching patterns within communities by fitting a polynomial function to lineage-through-time (LTT) plots. We illustrate how real and simulated community branching patterns can be more correctly described by ELDERness and can successfully predict ecosystem functioning. In particular, the evolutionary history of branching patterns can be encapsulated by the parameters of third-order polynomial functions and further measured through only two parameters, the “ELDERness surfaces.” These parameters captured variation in productivity of a grassland community better than existing phylogenetic diversity or diversification metrics and independent of species richness or presence of nitrogen fixers. Specifically, communities with small ELDERness surfaces (constant accumulation of lineages through time in LTT plots) were more productive, consistent with increased productivity resulting from complementary lineages combined with niche filling within lineages. Overall, while existing phylogenetic diversity metrics remain useful in many contexts, we suggest that our ELDERness approach better enables testing hypotheses that relate complex patterns of macroevolutionary history represented in local communities to ecosystem functioning. [ABSTRACT FROM AUTHOR]

Aim Several hypotheses postulate that species invasion is affected by an interplay between the phylogenetic position of the invading species and the phylogenetic structure of the invaded community type. Some of them suggest that phylogenetic relatedness of invaders to native species promotes naturalization, because phylogenetically related alien species tend to have similar environmental adaptations as native species. Others predict that phylogenetic relatedness hampers naturalization because of stronger competition of aliens with native species and shared enemies. Here we ask how phylogenetic diversity of native species affects invasion across community types. Location Czech Republic. Methods All major plant community types at a national scale ( n = 88) were characterized by their species pools, i.e. lists of species that can potentially occur there. Of the total number of 2306 species, 1785 were native, 246 were archaeophytes and 275 were neophytes. For each species pool, we related the number of alien species to the phylogenetic diversity of the native species pool, calculated as mean phylogenetic distance ( MPD) and mean nearest taxon distance ( MNTD), including null models. Results The number of alien species was related both to the phylogenetic structure of community types and to the phylogenetic position of alien species. Frequently disturbed herbaceous community types with strong phylogenetic clustering were more invaded than others, possibly due to disturbance acting as an environmental filter. Here, alien species increased the degree of phylogenetic clustering as they tended to be from the same lineages as native species. Such trends were not detected for phylogenetically more diverse community types such as forests. Main conclusions Our findings support the hypothesis that relatedness of invaders to native species promotes invasion because of their shared adaptations to the same environments. Alien species more strongly invade community types that are phylogenetically clustered, and because they tend to be related to native species, invaded community types become even more clustered. [ABSTRACT FROM AUTHOR]

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Question To what extent do historical and present-day management regimes and landscape characteristics affect the functional structure of semi-natural grassland communities? Location Semi-natural grasslands, the Baltic island of Öland, Sweden. Methods We assessed community functional structure within 475 (50 cm × 50 cm) semi-natural grassland vegetation plots using two indices: community-weighted mean trait values ( CWM) and functional divergence ( FD), calculated using the Rao quadratic entropy index. Spatially explicit regressions were used to assess the extent to which the CWM and FD for different plant traits are explained by past and present levels of local grazing management, and the present and historical characteristics of the surrounding landscape. Results Across traits, the CWM and FD of individual grasslands were strongly associated with current grazing intensity, but also with local management history and past landscape structure. Conclusions Our results indicate that grassland functional structure in the fragmented present-day landscape reflects not only present conditions, but also the historical context of the grassland fragments - where the presence of extensive grassland habitat in the surroundings provided a diverse pool of grazing-tolerant species. The study also suggests that information on landscape history, and its effects on the local species pool, may improve predictions of future plant community structure. [ABSTRACT FROM AUTHOR]

Questions Does the importance of biotic interactions between tree species increase during secondary forest succession? Do functional trait values become increasingly divergent from early towards late successional stages and how is functional diversity affected by trait identity, species identity and species richness effects? Location Gutianshan National Nature Reserve, Zhejiang Province, southeast China. Methods Based on 26 leaf and wood traits for 120 woody species, we calculated functional diversity, using Rao's formula for quadratic entropy, trait dissimilarity, defined as half the mean trait-based distance of all species in the community, and functional evenness, defined as the degree to which functional diversity is maximized. We employed randomization techniques to disentangle the effects of trait identity, species identity and species richness on these three components of functional diversity. Results Against expectations, functional diversity did not show any successional trend because the communities compensated for a loss in trait dissimilarity by distributing the trait values more evenly among the resident species, thus increasing functional evenness. Randomization tests showed that functional diversity was not affected by trait identity, by species identity or by species richness, which indicates that functional diversity was neither determined by particular single traits or by single species with outstanding trait values. Conclusions The constant functional diversity suggests constant functionality in this subtropical forest, which might temporally maintain stable immigration conditions during the course of succession, and thus provides an explanation why these subtropical forests become more species-rich with time. [ABSTRACT FROM AUTHOR]

Aim Positive regional correlations between biodiversity and human population have been detected for several taxonomic groups and geographical regions. Such correlations could have important conservation implications and have been mainly attributed to ecological factors, with little testing for an artefactual explanation: more populated regions may show higher biodiversity because they are more thoroughly surveyed. We tested the hypothesis that the correlation between people and herptile diversity in Europe is influenced by survey effort. Location Europe. Methods Although no explicit survey effort information is available in our dataset, we can divide Europe into three nested regions that were subjected to different levels of survey coverage. We compared species-people correlations among these regions, both with and without controlling for landscape diversity and latitude (a wrapper for energy-related variables whose individual effects on species richness were weaker). We also tested for relationships between human population and the distributions of single species. Results Both mean species richness and human population density increased as we restricted the analyses towards better-surveyed regions. Whether or not accounting for ecological factors, the positive relationship between species richness and human density was significant at the lower survey coverage levels, but faded as the analysis focused on better-surveyed regions and disappeared in the best-surveyed level. Single-species analyses revealed identical patterns, for both human-avoiding and human-adapted species. Main conclusions Our findings suggest an artefactual origin for the herptile-people correlation in Europe. More importantly, they highlight the importance of addressing sampling bias in biodiversity analyses, which may be possible even when survey effort is not recorded. We also emphasize the utility of noting survey effort along with biodiversity records and the need for better surveys of biodiversity in less populated areas. An adequate identification of conservation conflicts requires more rigorous assessments of the effects of survey effort on biodiversity data. [ABSTRACT FROM AUTHOR]

Questions Many methods have been developed to estimate species richness but few are useful for estimating regional richness. We compared the performance of commonly used non-parametric and area-based estimators with a particular focus on testing a newly developed but little tested maximum entropy method (MaxEnt). Location Tropical forest of Jianfengling Reserve, Hainan Island, China. Methods We extrapolated species richness on 12 estimators up to a larger regional scale - the reserve (472 km2) - where 164 25 m × 25 m quadrats were distributed on a grid of 160 km2 within the tropical forest. We also analysed the effects of base (or 'anchor') scale A0 on the species richness estimated ( Sest) with MaxEnt. Results Six non-parametric methods underestimated the species richness, while six area-based methods overestimated the species richness. The accuracy of the MaxEnt estimate ( Sest) was improved with the increase of base scale A0. Conclusions Our findings suggest non-parametric methods should not be used to estimate richness across heterogeneous landscapes but can be used in well-defined sampling areas. Jack2 is the best of the six non-parametric methods, while the logistic model and the MaxEnt method seem to be the best of the six area-based methods. Improvements to the MaxEnt method are possible but that will require reformulation of the method by considering species-abundance distributions other than log-series and more general spatial allocation rules. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim To determine relative effects of habitat type, climate and spatial pattern on species richness and composition of native and alien plant assemblages in central European cities. Location Central Europe, Belgium and the Netherlands. Methods The diversity of native and alien flora was analysed in 32 cities. In each city, plant species were recorded in seven 1-ha plots that represented seven urban habitat types with specific disturbance regimes. Plants were classified into native species, archaeophytes (introduced before ad 1500) and neophytes (introduced later). Two sets of explanatory variables were obtained for each city: climatic data and all-scale spatial variables generated by analysis of principal coordinates of neighbour matrices. For each group of species, the effect of habitat type, climate and spatial variables on variation in species composition was determined by variation partitioning. Responses of individual plant species to climatic variables were tested using a set of binomial regression models. Effects of climatic variables on the proportion of alien species were determined by linear regression. Results In all cities, 562 native plant species, 188 archaeophytes and 386 neophytes were recorded. Proportions of alien species varied among urban habitats. The proportion of native species decreased with increasing range and mean annual temperature, and increased with increasing precipitation. In contrast, proportions of archaeophytes and neophytes increased with mean annual temperature. However, spatial pattern explained a larger proportion of variation in species composition of the urban flora than climate. Archaeophytes were more uniformly distributed across the studied cities than the native species and neophytes. Urban habitats rich in native species also tended to be rich in archaeophytes and neophytes. Main conclusions Species richness and composition of central European urban floras are significantly affected by urban habitat types, climate and spatial pattern. Native species, archaeophytes and neophytes differ in their response to these factors. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim We investigate the importance of interacting species for current and potential future species distributions, the influence of their ecological characteristics on projected range shifts when considering or ignoring interacting species, and the consistency of observed relationships across different global change scenarios. Location Europe. Methods We developed ecological niche models (generalized linear models) for 36 European butterfly species and their larval host plants based on climate and land-use data. We projected future distributional changes using three integrated global change scenarios for 2080. Observed and projected mismatches in potential butterfly niche space and the niche space of their hosts were first used to assess changing range limitations due to interacting species and then to investigate the importance of different ecological characteristics. Results Most butterfly species were primarily limited by climate. Species dwelling in warm areas of Europe and tolerant to large variations in moisture conditions were projected to suffer less from global change. However, a gradient from climate to host plant control was apparent, reflecting the range size of the hosts. Future projections indicated increased mismatching of already host-plant-limited butterflies and their hosts. Butterflies that utilize plants with restricted ranges were projected to suffer most from global change. The directions of these relationships were consistent across the scenarios but the level of spatial mismatching of butterflies and their host plants increased with the severity of the scenario. Main conclusions Future changes in the co-occurrence of interacting species will depend on political and socio-economic development, suggesting that the composition of novel communities due to global change will depend on the way we create our future. A better knowledge of ecological species characteristics can be utilized to project the future fate and potential risk of extinction of interacting species leading to a better understanding of the consequences of changing biotic interactions. This will further enhance our abilities to assess and mitigate potential negative effects on ecosystem functions and services. [ABSTRACT FROM AUTHOR]

Abstract: Cities often have higher species diversity than the surrounding landscape. This diversity is important for both nature conservation and urban planning. The recreation of residents and the protection of species and habitats are simultaneous targets of maintaining urban green spaces. Data about the distribution and richness of species and their habitats have been compiled frequently; however, it is difficult and costly to measure the complete biodiversity of a region, necessitating useful surrogates. We tested species and habitat data in 27 protected areas in a Central German city and asked (1) whether the diversity of selected taxa acts as a surrogate for the diversity of other taxa and total investigated diversity, and (2) whether landscape structure and human impact explain species richness. Landscape structure metrics were based on soil and habitat types; human influence was measured as the degree of hemeroby. We tested and accounted for sample bias prior to analyses. (1) Vascular plant species richness explained total richness and single taxon richness best. (2) The size of a protected area was the most important predictor of species richness. After correcting for the effect of size, shape complexity, isolation, and matrix properties remained significant. Accordingly, the type of data frequently used for urban planning – collected over several years, by various persons for various purposes – is suitable regarding systematic conservation planning for species richness. The surrogate taxa concept applies in urban areas but with restrictions. Additionally, species richness should be examined in the context of both the city and its surrounding countryside. [ABSTRACT FROM AUTHOR]

Cities are hotspots of plant species richness, harboring more species than their rural surroundings, at least over large enough scales. However, species richness does not necessarily cover all aspects of biodiversity such as phylogenetic relationships. Ignoring these relationships, our understanding of how species assemblages develop and change in a changing environment remains incomplete. Given the high vascular plant species richness of urbanized areas in Germany, we asked whether these also have a higher phylogenetic diversity than rural areas, and whether phylogenetic diversity patterns differ systematically between species groups characterized by specific functional traits. Calculating the average phylogenetic distinctness of the total German flora and accounting for spatial autocorrelation, we show that phylogenetic diversity of urban areas does not reflect their high species richness. Hence, high urban species richness is mainly due to more closely related species that are functionally similar and able to deal with urbanization. This diminished phylogenetic information might decrease the flora’s capacity to respond to environmental changes. [ABSTRACT FROM AUTHOR]

Previous studies from Central Europe and North America showed that species richness is higher in urban than in rural landscapes. Do protected areas, which can be found in both city and countryside, reflect this species richness pattern? The impact of urban land-use might reduce conservation success and necessitate special management strategies. We compared species richness and species spatial turnover of selected animal and plant taxa (carabids, butterflies, snails, birds, lichens, mosses, vascular plants) in 30 protected areas in the city of Halle and 56 protected areas in the adjacent rural district of Saalkreis (Central Germany). Species were mapped by experienced biologists within a systematic species inventory. We corrected species numbers for the effects of landscape structure (e.g. size, shape and distance of habitats) which might influence species diversity beyond urbanisation effects. Butterflies, birds and lichens had significantly higher species numbers in the rural protected areas. Species spatial turnover was higher among urban areas than among rural areas or pairs of urban and rural areas for most taxa. Diversity in all taxa depended on the size of a protected area. We discussed these patterns in the context of the general urban-rural species diversity patterns. Our results indicate an increasing isolation of species assemblages with urbanisation and highlight that space for protected areas is even more limited in urban than rural areas. An effective conservation of urban species diversity should include both typical urban and semi-natural habitats to cover the full range of species living in cities. [ABSTRACT FROM AUTHOR]