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Aim: Biological invasions are likely determined by species dispersal strategies as well as environmental characteristics of a recipient region, especially climate and human impact. However, the contribution of climatic factors, human impact, and dispersal strategies in driving invasion processes is still controversial and not well embedded in the existing theoretical considerations. Here, we study how climate, species dispersal strategies, and human impact determine plant invasion processes on islands distributed in all major oceans in the context of directional ecological filtering. Location: Six mountainous, tropical, and subtropical islands in three major oceans: Island of Hawai'i and Maui (Pacific), Tenerife and La Palma (Atlantic), and La Réunion and Socotra (Indian Ocean). Taxon: Vascular Plants. Methods: We recorded 360 non-native species in 218 plots along roadside elevational transects covering the major temperature, precipitation and human impact (i.e., road density) gradients of the islands. We collected dispersal strategies for a majority of the recorded species and calculated the environmental niche per species using a hypervolume approach. Results: Non-native species’ generalism (i.e., mean community niche width) increased with precipitation, elevation and human impact but showed no relationship with temperature. Increasing precipitation led to environmental filtering of non-native species resulting in more generalist species under high precipitation conditions. We found no directional filtering for temperature but an optimum range of most species between 10 and 20°C. Niche widths of non-native species increased with the prevalence of certain dispersal strategies, particularly anemochory and anthropochory. Main conclusions: Plant invasion on tropical and subtropical islands seems to be mainly driven by precipitation and human impact, while temperature seems to be of little importance. Furthermore, anemochory and anthropochory are dispersal strategies associated with large niche widths of non-native species. Our study allows a more detailed look at the mechanisms behind directional ecological filtering of non-native plant species in non-temperature-limited ecosystems.

Tea (Camellia sinensis) is a popular beverage that is consumed globally. However, a better understanding of potentially toxic elements (PTEs) content in tea leaves and infusion is necessary to minimize risk on human health. Therefore, 249 tea samples (grown in different areas) covering six types of tea were collected in China to investigate the PTEs contents, identify their potential source and assess the health risk associated with drinking tea. PTE contents in tea leaves across six tea types were ND-0.900 (Cd), 0.005-2.133 (As), ND-5.679 (Pb), ND-13.86 (Cr), 1.601-22.93 (Ni), ND-2.048 (Se), 0.109-622.4 (F), 13.02-269.9 (Rb), 1.845-50.88 (Sr), and 2.796-53.23 (Ba) mg/kg. The result of tea infusion showed that 14.3 %-44.1 % (green tea), 14.5 %-46.7 % (black tea), 10.5 %-25.3 % (dark tea), 13.6 %-34.2 % (oolong tea), 16.9 %-40.7 % (yellow tea), and 19.9 %-35.1 % (white tea) of F were released. All tea types, except green tea, exhibited comparatively low leachability of Cd, As, Pb and Cr in tea infusion. The source apportionment revealed that PTEs in tea leaves mainly originated from soil parental materials, while industrial activities, fertilizer application, and manufacturing processes may contribute to exogenous Se, Cd, As, and Cr accumulation. Health risk assessment indicated that F in tea infusion dominated the health risk. Humans may be exposed to a higher health risk by drinking green tea compared to that of other tea types. Nevertheless, the long-term tea consumption is less likely to contribute to pronounced non-carcinogenic and carcinogenic risks. This study confirmed that tea consumption is an important and direct pathway of PTEs uptake in humans. The health risk associated with drinking tea should be of concern.

In lichen symbioses, fungal secondary metabolites provide UV protection on which lichen algae such as trebouxiophycean green algae-the most prominent group of photobionts in lichen symbioses-sensitively depend. These metabolites differ in their UV absorbance capability and solvability, and thus vary in their propensity of being leached from the lichen body in humid and warm environments, with still unknown implications for the global distribution of lichens. In this study covering more than 10,000 lichenised fungal species, we show that the occurrence of fungal-derived metabolites in combination with their UV absorbance capability and their probability of being leached in warm and humid environments are important eco-evolutionary drivers of global lichen distribution. Fungal-derived UV protection seems to represent an indirect environmental adaptation in which the lichen fungus invests to protect the trebouxiophycean photobiont from high UV radiation in warm and humid climates and, by doing this, secures its carbon source.

Cadmium (Cd) pollution of agricultural soil is of public concern due to its high potential toxicity and mobility. This study aimed to reveal the risk of Cd accumulation in soil and wheat/maize systems, with a specific focus on the source-specific ecological risk, human health risk and Cd enrichment model. For this we investigated more than 6100 paired soil and grain samples with 216 datasets including soil Cd contents, soil pH and grain Cd contents of 85 sites from China. The results showed that mining activities, sewage irrigation, industrial activities and agricultural practices were the critical factors causing Cd accumulation in wheat and maize cultivated sites. Thereinto, mining activities contributed to a higher Cd accumulation risk in the southwest China and Middle Yellow River regions; sewage irrigation influenced the Cd accumulation in the North China Plain. In addition, the investigated sites were classified into different categories by comparing their soil and grain Cd contents with the Chinese soil screening values and food safety values, respectively. Cd enrichment models were developed to predict the Cd levels in wheat and maize grains. The results showed that the models exhibited a good performance for predicting the grain Cd contents among safe and warning sites of wheat (R

Questions How does the diversity of native, endemic and alien plant species, as well as the diversity of plant life forms, change during primary succession on lava flows of an oceanic‐volcanic island? How do environmental factors such as moisture and soil properties alter diversity during primary succession? Location La Palma, Canary Islands. Methods We recorded vascular plants and bryophytes in 210 plots on a chronosequence of nine lava flows spanning approx. 6,000years and covering an elevational range of 1,100m. In a subset (n=78 plots) we collected and analyzed soil samples for soil nitrogen and plant‐available phosphorus. We used generalized linear models, variance partitioning and structural equation models (SEMs) to analyze the data. Results Species richness, endemic richness and alien richness increased with time. Natives dominated during early successional stages, whereas endemics and aliens increased with time. At early successional stages, vascular plants and bryophytes had an equal contribution to the species pool, while vascular plants increased up to an 80% contribution at later stages. In the variance partitioning and SEMs, time was the only consistent factor influencing different aspects of diversity during succession (species richness, endemic richness and percent endemism). Only for percent endemism did soil attributes have a substantial impact. Conclusion Primary succession on lava flows on La Palma shows a pattern of increasing overall diversity, endemism and alien richness with time. Time is the only factor consistently explaining diversity and endemism, indicating that environmental influences such as climate and soil properties do not substantially alter them during primary succession. Our study contributes to understanding how different facets of diversity assemble through time by using an understudied, yet important island system, and, for the first time, specifically addresses how endemics contribute to the process of primary succession.

A flexible use of the crassulacean acid metabolism (CAM) has been hypothesised to represent an intermediate stage along a C3 to full CAM evolutionary continuum, when relative contributions of C3 vs CAM metabolism are co-determined by evolutionary history and prevailing environmental constraints. However, evidence for such eco-evolutionary interdependencies is lacking. We studied these interdependencies for the leaf-succulent genus Drosanthemum (Aizoaceae, Southern African Succulent Karoo) by testing for relationships between leaf δ13 C diagnostic for CAM dependence (i.e. contribution of C3 and CAM to net carbon gain), and climatic variables related to temperature and precipitation and their temporal variation. We further quantified the effects of shared phylogenetic ancestry on CAM dependence and its relation to climate. CAM dependence is predicted by rainfall and its temporal variation, with high predictive power of rainfall constancy (temporal entropy). The predictive power of rainfall seasonality and temperature-related variables was negligible. Evolutionary history of the tested clades significantly affected the relationship between rainfall constancy and CAM dependence. We argue that higher CAM dependence might provide an adaptive advantage in increasingly unpredictable rainfall environments when the anatomic exaptation (succulence) is already present. These observations might shed light on the evolution of full CAM.

A fundamental challenge in experimental ecology is to capture nonlinearities of ecological responses to interacting environmental drivers. Here, we demonstrate that gradient designs outperform replicated designs for detecting and quantifying nonlinear responses. We report the results of (1) multiple computer simulations and (2) two purpose-designed empirical experiments. The findings consistently revealed that unreplicated sampling at a maximum number of sampling locations maximised prediction success (i.e. the R² to the known truth) irrespective of the amount of stochasticity and the underlying response surfaces, including combinations of two linear, unimodal or saturating drivers. For the two empirical experiments, the same pattern was found, with gradient designs outperforming replicated designs in revealing the response surfaces of underlying drivers. Our findings suggest that a move to gradient designs in ecological experiments could be a major step towards unravelling underlying response patterns to continuous and interacting environmental drivers in a feasible and statistically powerful way.

For hundreds of millions of years, large vertebrates (megafauna) have inhabited most of the ecosystems on our planet. During the late Quaternary, notably during the Late Pleistocene and the early Holocene, Earth experienced a rapid extinction of large, terrestrial vertebrates. While much attention has been paid to understanding the causes of this massive megafauna extinction, less attention has been given to understanding the impacts of loss of megafauna on other organisms with whom they interacted. In this review, we discuss how the loss of megafauna disrupted and reshaped ecological interactions, and explore the ecological consequences of the ongoing decline of large vertebrates. Numerous late Quaternary extinct species of predators, parasites, commensals and mutualistic partners were associated with megafauna and were probably lost due to their strict dependence upon them (co-extinctions). Moreover, many extant species have megafauna-adapted traits that provided evolutionary benefits under past megafauna-rich conditions, but are now of no or limited use (anachronisms). Morphological evolution and behavioural changes allowed some of these species partially to overcome the absence of megafauna. Although the extinction of megafauna led to a number of co-extinction events, several species that likely co-evolved with megafauna established new interactions with humans and their domestic animals. Species that were highly specialized in interactions with megafauna, such as large predators, specialized parasites, and large commensalists (e.g. scavengers, dung beetles), and could not adapt to new hosts or prey were more likely to die out. Partners that were less megafauna dependent persisted because of behavioural plasticity or by shifting their dependency to humans via domestication, facilitation or pathogen spill-over, or through interactions with domestic megafauna. We argue that the ongoing extinction of the extant megafauna in the Anthropocene will catalyse another wave of co-extinctions due to the enormous diversity of key ecological interactions and functional roles provided by the megafauna.

Aims Current rates of biodiversity loss do not allow for inefficient monitoring. Optimized monitoring maximizes the ratio between information and sampling effort (i.e., time and costs). Sampling effort increases with the number and size of sampling units. We hypothesize that an optimal size and number of sampling units can be determined providing maximal information via minimal effort. We apply an approach that identifies the optimal size and number of sampling quadrats. The approach can be adapted to any study system. Here we focus on alpine grassland, a diverse but threatened ecosystem. Location Gran Paradiso National Park, Italy. Methods We sampled nine 20 m × 20 m-plots. Each plot consisted of 100 2 m × 2 m-subplots. Species richness and Shannon diversity were quantified for different sizes and quantities of subplots. We simulated larger subplot sizes by unifying adjacent 2 m × 2 m-subplots. Shannon’s information entropy was used to quantify information content among richness and diversity values resulting from different subplot sizes and quantities. The optimal size and number of subplots is the lowest size and number of subplots returning maximal information. This optimal subplot size and number was determined by Mood’s median test and segmented linear regression, respectively. Results The information content among richness values increased with subplot size, irrespective of the number of subplots. Therefore, the largest subplot size available is the optimal size for information about richness. Information content among diversity values increased with subplot size if 18 or less subplots were considered, and decreased if at least 27 subplots were sampled. The subplot quantity consequently determined whether the smallest or largest subplot size available is the optimal size, and whether the optimal size can be generalized across richness and diversity. Given a 2 m × 2 m size, we estimated an optimal quantity of 54. Given a size of 4 m × 4 m, we estimated an optimal number of 36. The optimal number of plots can be generalized across both indices because it barely differed between the indices given a fixed subplot size. Conclusions The information content among richness and diversity values depends on the sampling scale. Shannon’s information entropy can be used to identify the optimal number and size of plots that return most information with least sampling effort. Our approach can be adapted to other study systems to create an efficient in-situ sampling design, which improves biodiversity monitoring and conservation under rapid environmental change.

International audience; Increasing human pressure on strongly defaunated ecosystems is characteristic of the Anthropocene and calls for proactive restoration approaches that promote self-sustaining, functioning ecosystems. However, the suitability of novel restoration concepts such as trophic rewilding is still under discussion given fragmentary empirical data and limited theory development. Here, we develop a theoretical framework that integrates the concept of 'ecological memory' into trophic rewilding. The ecological memory of an ecosystem is defined as an ecosystem's accumulated abiotic and biotic material and information legacies from past dynamics. By summarising existing knowledge about the ecological effects of megafauna extinction and rewilding across a large range of spatial and temporal scales, we identify two key drivers of ecosystem responses to trophic rewilding: (i) impact potential of (re)introduced megafauna, and (ii) ecological memory characterising the focal ecosystem. The impact potential of (re)introduced megafauna species can be estimated from species properties such as lifetime per capita engineering capacity, population density, home range size and niche overlap with resident species. The importance of ecological memory characterising the focal ecosystem depends on (i) the absolute time since megafauna loss, (ii) the speed of abiotic and biotic turnover, (iii) the strength of species interactions characterising the focal ecosystem, and (iv) the compensatory capacity of surrounding source ecosystems. These properties related to the focal and surrounding ecosystems mediate material and information legacies (its ecological memory) and modulate the net ecosystem impact of (re)introduced megafauna species. We provide practical advice about how to quantify all these properties while highlighting the strong link between ecological memory and historically contingent ecosystem trajectories. With this newly established ecological memory-rewilding framework, we hope to guide future empirical studies that investigate the ecological effects of trophic rewilding and other ecosystem-restoration approaches. The proposed integrated conceptual framework should also assist managers and decision makers to anticipate the possible trajectories of ecosystem dynamics after restoration actions and to weigh plausible alternatives. This will help practitioners to develop adaptive management strategies for trophic rewilding that could facilitate sustainable management of functioning ecosystems in an increasingly human-dominated world.

Aims Acidification by airborne pollution strongly degraded terrestrial and aquatic ecosystems until the late 20th century. Although geochemical recovery has been observed since then, there has been little recovery of ecological communities, and the reasons are unclear. Positive feedbacks between anthropogenic acidification and ecosystem engineers are likely to contribute to this lag in recovery, but are under-investigated so far. Here we hypothesize that positive feedbacks between past anthropogenic acidification and on-going biogenic habitat modification by peat moss species (genus Sphagnum) will have long-term effects on plant community composition of acidified spring fens. Location Spring fens in forest landscapes of central Germany's siliceous mountain ranges impacted by anthropogenic acidification until the late 1980s, and with strong increases in abundance of Sphagnum during the last 25 yrs. Methods Vegetation surveys (vascular plants, mosses and liverworts) and hydro-chemical water measurements of 54 spring fens over a study period of 25 yrs (1989–2013). Measurements of water pH and discharge were used, in combination with Ellenberg indicator values of the occurring plant species, to investigate the joint effects of anthropogenic acidification and biogenic habitat modification. Results Changing plant communities (excluding Sphagnum spp.) indicated significant increases in acidification of spring fens with high Sphagnum cover, although pH of the outpouring groundwater showed no temporal trends. Path analysis revealed significant enhancing effects of Sphagnum abundance on the community-indicated acidity, which was independent of the abiotic acidity regime (water pH). With increasing species richness through time, community assembly became increasingly similar and shifted towards acid-tolerant species. Characteristic plant species of non-acidified spring fens like Chrysosplenium oppositifolium were replaced by generalist grass, sedge and tree species (e.g., Picea abies, Fagus sylvatica, Calamagrostis villosa and Carex remota). Conclusions Based on long-term monitoring data we show that biogenic habitat modification by ecosystem engineers can significantly change plant community composition on a decadal scale in a landscape where historic anthropogenic acidification heavily impacted ecosystem functioning. These complex functional legacies stress the importance of considering the history and memory of ecosystems in global change impact research.

Aim Scale dependence of patterns and processes remains one of the major unresolved problems in ecology. The responses of ecosystems to environmental stressors are reported to be strongly scale dependent, but projections of the effects of climate change on species' distributions are still restricted to particular scales and knowledge about scale dependence is lacking. Here we propose that the scale dependence of those species' niche dimensions related to climate change is strongly related to the strength of climatic cross-scale links. More specifically, we hypothesize that the strong cross-scale links between micro- and macroclimatic conditions are related to high cross-scale similarity (low scale dependence) of species' realized temperature niches and, thus, species' spatial distributions. Location This study covers seven orders of magnitude of spatial scale, ranging from local-scale (below a metre) and regional-scale (kilometre) investigations in central European wetland ecosystems to continental-scale (thousands of kilometres) studies of species' distributions. Methods We combined data on the spatial occurrence of species (vegetation records at local and regional scales, digitized distribution maps at the continental scale) with information about the corresponding temperature regime of vascular plant species occurring in environmentally stable wetland ecosystems characterized by strong cross-scale links between micro- and macroclimatic conditions. Results We observed high cross-scale similarity of the characteristics of species temperature niches across seven orders of magnitude of spatial scale. However, the importance of temperature as an abiotic driver decreased nonlinearly with decreasing scale, suggesting greater importance of additional (biotic) drivers of species' occurrence at small spatial scales. Main conclusions We report high cross-scale similarity of realized temperature niches for species inhabiting ecosystems where small-scale environmental noise is low and cross-scale links between micro- and macroclimatic conditions are strong. By highlighting a strong relationship between abiotic and biotic cross-scale similarity, our results will help to improve niche-based species distribution modelling, one of the major assessment tools for determining the ecological effects of climate change.

AimCold events determine the distributional range limits of woody species. Despite global warming, the magnitude of late frost events in boreal and temperate regions is not expected to change. Hence, the risk for late spring frost damage of woody species may increase with an earlier onset of the growing season. Here, we investigated biogeographical, phenological and phylogenetic effects on late frost sensitivity. LocationEcological-Botanical Gardens Bayreuth, Germany (49 degrees 5545N, 11 degrees 3510E). MethodsWe inspected 170 woody species in the Ecological-Botanical Gardens from across the entire Northern Hemisphere for frost damage after an extreme late frost event in May 2011 (air temperature -4.3 degrees C after leaf unfolding of all species). Distribution range characteristics, climatic parameters of place of origin and phenological strategy were linked to sensitivity to the late frost event. ResultsThe northern distribution limit and the range in continentality across the distributional ranges correlated negatively with a taxon's late frost sensitivity (pseudo-R-2=0.42, pseudo-R-2=0.33, respectively). Sensitivity to the late frost event was well explained by the climatic conditions within species' native ranges (boosted regression trees;receiver operating characteristic 0.737). Average (1950-2000) May minimum temperature in species' native ranges was the main explanatory variable of late frost sensitivity (51.7% of explained variance). Phylogenetic relatedness explained additional variance in sensitivity to the late frost event. Sensitivity to the late frost event further correlates well with species phenological strategy. Frost-tolerant species flushed on average 2 weeks earlier than frost-sensitive species. Main conclusionsRange characteristics and the prevalent climatic parameters across species native ranges are strongly related to their susceptibility to late spring frost damage. Further, more late frost-sensitive species unfolded their leaves later than more tolerant species and late frost tolerance is phylogenetically conserved. Thus, late frost sensitivity may challenge natural and human-assisted migration of woody species under global warming.

The ongoing down-sizing of the global mammal communities is assumed to have subsequent effects on mutualistic species communities. Dung beetles co-evolved with large-sized animals since millennia and depend on the megafauna feces of an appropriate size. Mammal community down-sizing as a result of past and ongoing megafauna losses is therefore likely to result in a down-sizing of dung beetle communities. However, empirical evidence for this co-down-sizing is lacking especially on larger spatial scales and over extended periods of time. Here, we show a significant down-sizing of European dung beetle assemblages over the last 53 000 years by relating Quaternary fossil records with trait information on body size of beetles. This significant down-sizing of dung beetle communities was thereby not linear, but characterized by a weak decrease until the early Holocene but a strong acceleration in the recent pre-history, from 6-7000 years BP onwards. This acceleration of down-sizing coincides with the completion of the Quaternary megafauna extinction and the start of major shifts in human agricultural land-use. In contrast, assemblage mean body size of non-coprophagous scarabids as well as ground beetles - two groups of beetles with no or weak relations to megafauna - was observed to increase towards the present with an acceleration of body size increase coinciding with the onset of late-glacial warming (14 200 years BP). In summary, the observed late-Quaternary down-sizing of European dung beetle communities is consistent with an effect of pre-historic megafauna losses, and not with the coincident general warming. Ongoing down-sizing of mammal communities is therefore likely to result in further down-sizing of dung beetle assemblages, with potential effects on their important role for nutrient cycling and secondary seed dispersal in natural and extensive agro-ecosystems. Future nature management initiatives could halt or even reverse this functional diversity loss via effective protection or restoration of megafauna communities.

1. Natural scientists and especially ecologists use manipulative experiments or field observations along gradients to differentiate patterns driven by processes from those caused by random noise. A well-conceived sampling design is essential for identifying, analysing and reporting underlying patterns in a statistically solid and reproducible manner, given the normal restrictions in labour, time and money. However, a technical guideline about an adequate sampling design to maximize prediction success under restricted resources is lacking. This study aims at developing such a solid and reproducible guideline for sampling along gradients in all fields of ecology and science in general.2. We conducted simulations with artificial data for five common response types known in ecology, each represented by a simple function (no response, linear, exponential, symmetric unimodal and asymmetric unimodal). In the simulations we accounted for different levels of random and systematic error, the two sources of noise in ecological data. We quantified prediction success for varying total sample size, number of locations sampled along a spatial/temporal gradient and number of replicates per sampled location.3. The number of replicates becomes more important with increasing random error, whereas replicates become less relevant for a systematic error bigger than 20% of total variation. Thus, if high levels of systematic error are indicated or expected (e.g. in field studies with spatial autocorrelation, unaccountable additional environmental drivers, or population clustering), continuous sampling with little to no replication is recommended. In contrast, sampling design with replications is recommended in studies that can control for systematic errors. In a setting that is characteristic for ecological experiments and field studies strictly controlling for undeterminable systematic error (random error ≥ 10% and systematic error ≤ 10% of total variation), prediction success was best for an intermediate number of sampled locations along the gradient (10-15) and a low number of replicates per location (3).4. Our findings from reproducible, statistical simulations will help to design appropriate and efficient sampling approaches and to avoid erroneous conclusions based on studies with flawed sampling design, which is currently one of the main targets of public criticism against science.

Body colouration is of high evolutionary relevance for most animals. Several competing hypotheses exist regarding the evolutionary reasons for animal colouration ranging from predator avoidance and sexual advertisement to neutral selection. Among these hypotheses, biophysical principles suggest the thermoregulatory importance of dark colouration which in turn strongly depends on species body size. This body size – darkness trade-off is based on sound theoretical background conceptualized in the thermal melanism hypothesis and is confirmed by numerous case studies for individual species. However, evidence for the general relevance of this trade-off on large spatial and taxonomic scale is still missing. Here we specifically focus on this body size – colouration trade-off for a hyper-diverse and cosmopolitan group of insects, namely ground beetles. We combined colour information with trait data and distributional as well as bioclimatic attributes for more than 1000 carabid species from the entire Western Palearctic. We quantified species-specific body colouration from high-quality, standardised digital photographs using the Munsell colour system. We detect a strong increase of colour darkness with body size from small to medium-sized carabids up to a body size threshold of 15 mm which is consistent with the thermal melanism hypothesis. However, body size showed no effect above this threshold and colour darkness remained constantly high which is in accordance with previous ideas about the size-dependency of thermoregulative control mechanisms (size dependence hypothesis). By demonstrating a strong tendency towards darkness with increasing body size, we illustrate the inter-specific relevance of body colouration for this cosmopolitan group of ectotherms on a continental scale. The putative thermoregulative trade-off between body size and melanism seems to be of significant importance for carabids on a broad spatial scale and may be a general but still underestimated phenomenon for ectotherms in general, although other mechanistic drivers cannot be completely neglected.

© 2017 The Authors., [Aim] Rarity—an important measure for conservation biogeography—can vary over many orders of magnitude. However, it is unclear which regional-scale abiotic conditions drive processes affecting rarity of endemic species on islands. To support conservation efforts, we (1) assess the main abiotic drivers of endemic rarity, (2) determine how well existing protected areas (PAs) coincide with hotspots of endemic rarity and (3) introduce and evaluate a new hypervolume-based rarity estimator., [Location] La Palma (Canary Islands)., [Methods] We recorded all present endemic vascular plant species in 1,212 plots covering the entire island. We calculated endemic rarity (corrected range-rarity richness for endemics) using a rarity estimation approach based on kernel density estimations (hypervolume approach). We performed a sensitivity analysis based on multiple linear regressions and relative importance estimations of environmental drivers to estimate the performance of the hypervolume-based rarity estimation compared to standard methods (occurrence frequency, convex hulls, alpha hulls)., [Results] Climate variables (mean annual temperature, climatic rarity, precipitation variability) best explained archipelago endemic (AE) and single-island endemic (SIE) rarity. Existing PAs covered the majority of AE and SIE rarity, especially national and natural parks as well as the Natura 2000 sites. In our study system, hypervolumes performed better than standard measures of range size., [Main conclusion] Both AE and SIE rarity on La Palma show a clear spatial pattern, with hotspots of endemic rarity found at high elevations and in rare climates, presumably owing to geographical and climatic constraints and possibly anthropogenic pressure (e.g., land use, introduced herbivores, fire). Areas of high rarity estimates coincide with the distribution and extent of PAs on La Palma, especially since the recent addition of the Natura 2000 sites. The hypervolume approach is a promising tool to estimate species range sizes, and can be applied on all scales where point/plot data are available., This work contributed to and was partially supported by the European H2020 Project 641762 ECOPOTENTIAL: Improving future ecosystem benefits through Earth Observations.

For hundreds of millions of years, large vertebrates (megafauna) have inhabited most of the ecosystems on our planet. During the late Quaternary, notably during the Late Pleistocene and the early Holocene, Earth experienced a rapid extinction of large, terrestrial vertebrates. While much attention has been paid to understanding the causes of this massive megafauna extinction, less attention has been given to understanding the impacts of loss of megafauna on other organisms with whom they interacted. In this review, we discuss how the loss of megafauna disrupted and reshaped ecological interactions, and explore the ecological consequences of the ongoing decline of large vertebrates. Numerous late Quaternary extinct species of predators, parasites, commensals and mutualistic partners were associated with megafauna and were probably lost due to their strict dependence upon them (co-extinctions). Moreover, many extant species have megafauna-adapted traits that provided evolutionary benefits under past megafauna-rich conditions, but are now of no or limited use (anachronisms). Morphological evolution and behavioural changes allowed some of these species partially to overcome the absence of megafauna. Although the extinction of megafauna led to a number of co-extinction events, several species that likely co-evolved with megafauna established new interactions with humans and their domestic animals. Species that were highly specialized in interactions with megafauna, such as large predators, specialized parasites, and large commensalists (e.g. scavengers, dung beetles), and could not adapt to new hosts or prey were more likely to die out. Partners that were less megafauna dependent persisted because of behavioural plasticity or by shifting their dependency to humans via domestication, facilitation or pathogen spill-over, or through interactions with domestic megafauna. We argue that the ongoing extinction of the extant megafauna in the Anthropocene will catalyse another wave of co-extinctions due to the enormous diversity of key ecological interactions and functional roles provided by the megafauna.

Climate and landscape change are expected to significantly affect trophic interactions, which will especially harm top predators such as the golden eagle Aquila chrysaetos. Availability of optimal prey is recognized to influence reproductive success of raptors on a regional scale. For the golden eagle, medium-sized prey species between 0.5 and 5 kg are widely considered to be optimal prey during the breeding season, whereas smaller and larger species are deemed as energetically sub-optimal. However, knowledge about the effects of optimal prey availability is still scarce on larger scales. To decrease this apparent knowledge gap, we combined biogeographical information on range margins with information about the foraging behaviour and reproductive success of golden eagles from 67 studies spanning the Northern Hemisphere. We hypothesized that availability of optimal prey will affect foraging behaviour and breeding success and, thus, distribution patterns of the golden eagle not only on a local but also on a continental scale. We correlated the diet breadth quantifying foraging generalism, breeding success and proportions of small ( 5 kg) prey species within the diet with the minimum distance of the examined eagles to the actual species distribution boundary. Closer to the range edge, we observed decreased proportions of medium-sized prey species and decreasing breeding success of golden eagles. Diet breadth as well as proportions of small and large-sized prey species increased, however, towards the range edge. Thus, availability of optimal-sized prey species seems to be a crucial driver of foraging behaviour, breeding success and distribution of golden eagles on a continental scale. However, underlying effects of landscape characteristics and human influence on optimal prey availability has to be investigated in further large-scale studies to fully understand the major threats facing the golden eagle and possibly other large terrestrial birds of prey.

Positive plant-plant interactions (i.e. facilitation) receive increasing attention as a potentially important driver of community assembly. We conducted a systematic literature review indicating broad support for positive effects of potential facilitator species. However, a large majority of the reviewed studies (83% for field studies, 57% for experiment) share a similar risk of misinterpretation as they assess facilitative effects by comparing plots inhabited by a potential facilitator with randomly placed control plots nearby (paired sampling). As the distribution of facilitator species may itself be environmentally driven, species coexistence caused by facilitation cannot exclusively be separated from environmental effects (habitat sharing). Based on simulated plant communities and sampling protocols, we show how non-random coexistence can occur in the absence of facilitation. This is relevant as both the effect of spatial environmental heterogeneity and of facilitation (stress-gradient hypothesis) are expected to increase with environmental harshness. Nevertheless, 58% of facilitation studies neither undertook measures to minimize potential biases in their sampling approaches nor did they acknowledge such limitations in the discussion. Attention to this problem has significantly decreased in recent years. We propose that facilitation studies could be improved (i) by using random sampling for association studies, (ii) by co-analysing environmental factors, or (iii) by experimentally establishing presumed facilitators. Experimental approaches mimicking facilitative plant characteristics can help to identify facilitation mechanisms. Combining approaches and including functional traits of the involved species should further strengthen inference.

Atmospheric acidic depositions have strongly altered the functioning and biodiversity of Central European forest ecosystems. Most impacts occurred until the end of the 20th century but the situation substantially improved thereafter caused by legal regulations in the late 1980's to reduce acidifying atmospheric pollution. Since then slow recovery from acidification has been observed in forested catchments and adjacent waters. However, trends of recovery are inconsistent and underlying mechanisms diminishing recovery are still poorly understood. We propose that the input of road salt can significantly affect acidity regime and acidification recovery of forest ecosystems. By comparing the discharge hydro-chemistry and plant community composition of springs fed by forested catchments with and without high levels of salt input over two decades we observed a significant suppression of recovery and elevated levels of nutrient leaching (K+, Ca2 + and Mg2 +) in highly salt contaminated catchments. We show that the pollution of near-surface groundwater (interflow) by road salt application can have lasting effects on ecosystem processes over distances of several hundred metres apart from the salt emitting road.

Background: Positive plant-plant interactions similar to specialised plant growth forms are potential strategies to overcome the environmental harshness of Afro-alpine ecosystems. However, knowledge about plant-plant interactions is limited for African alpine regions. Aims: We investigated the ameliorative effect of the densely leaved dwarf shrub Helichrysum citrispinum on two frequently co-occurring herbaceous plant species in the alpine zone of Mt. Kilimanjaro. Methods: We recorded microclimatic conditions, plant water potentials and gross primary production (GPP) for plants of the low-growing perennial Alchemilla johnstonii and the tussock grass Festuca abyssinica and compared these parameters between open sites and under H. citrispinum shrubs between July and August 2012. Results: Shrubs significantly buffered daily variation and extreme values of irradiation, air-, plant surface- and soil-temperatures as well as vapour pressure deficit. We found enhanced plant water potentials and gross primary production for shaded plants of both species investigated; ameliorative effects were higher for A. johnstonii than for F. abyssinica. Conclusions: Habitat amelioration of H. citrispinum significantly improves the productivity of plant species that grow under the shrub, although the net outcome may be affected by interspecific growth form differences. Future studies on positive plant-plant interactions should more strongly focus on the ecophysiological consequences of habitat amelioration.

The processes underlying species’ dominance patterns and community composition are insufficiently investigated for springs, yet these systems, which are believed to be very stable environments, represent an important interface between aquatic and terrestrial habitats contributing significantly to local and regional diversity. We studied the dominance patterns and plant community composition of 238 springs in Central Europe. According to the conventional ecological belief we hypothesized (1) a positive relationship between local abundance and regional distribution of spring plant species, as well as between species commonness and species’ realized breadth and (2) the occurrence of oligarchic species similar to other stable environments like tropical forests. Based on previous studies on this springs, we furthermore hypothesized (3) that water pH—essentially a proxy for nutrient availability—is the major driver of spatial compositional dissimilarity, i.e. beta-diversity. We tested these three hypotheses by using species commonness estimates, realized niche space and generalized dissimilarity modelling based on hydrochemistry. In line with conventional wisdom, we report a positive relationship between local abundance, species commonness and regional distribution for the majority of the species. In contradiction to other systems, we found both specialist and generalist species to be locally dominant and regionally widespread, thus common, while species with intermediate niche breadth showed the lowest commonness values. However, we detected three oligarchic species, exceeding all other species in local abundance and regional distribution, which did not follow these relationships. Both dominance relations (oligarchy) and community composition were mainly driven by water temperature and concentration of elements related to acidity regime (Al, Cd, Ca and Mg), although much of the variation in both remained unexplained. Thus, further research should focus on biotic interactions, which are likely to be important drivers of plant community composition in springs.