One of the best-known general patterns in island biogeography is the species–isolation relationship (SIR), a decrease in the number of native species with increasing island isolation that is linked ...to lower rates of natural dispersal and colonization on remote oceanic islands. However, during recent centuries, the anthropogenic introduction of alien species has increasingly gained importance and altered the composition and richness of island species pools. We analyzed a large dataset for alien and native plants, ants, reptiles, mammals, and birds on 257 (sub) tropical islands, and showed that, except for birds, the number of naturalized alien species increases with isolation for all taxa, a pattern that is opposite to the negative SIR of native species. We argue that the reversal of the SIR for alien species is driven by an increase in island invasibility due to reduced diversity and increased ecological naiveté of native biota on the more remote islands.
Withstanding extinction while facing rapid climate change depends on a species' ability to track its ecological niche or to evolve a new one. Current methods that predict climate-driven species' ...range shifts use ecological modelling without eco-evolutionary dynamics. Here we present an eco-evolutionary forecasting framework that combines niche modelling with individual-based demographic and genetic simulations. Applying our approach to four endemic perennial plant species of the Austrian Alps, we show that accounting for eco-evolutionary dynamics when predicting species' responses to climate change is crucial. Perennial species persist in unsuitable habitats longer than predicted by niche modelling, causing delayed range losses; however, their evolutionary responses are constrained because long-lived adults produce increasingly maladapted offspring. Decreasing population size due to maladaptation occurs faster than the contraction of the species range, especially for the most abundant species. Monitoring of species' local abundance rather than their range may likely better inform on species' extinction risks under climate change.
In the face of the growing challenges brought about by human activities, effective planning and decision-making in biodiversity and ecosystem conservation, restoration, and sustainable development ...are urgently needed. Ecological models can play a key role in supporting this need and helping to safeguard the natural assets that underpin human wellbeing and support life on land and below water (United Nations Sustainable Development Goals; SDG 15 & 14). The urgency and complexity of safeguarding forest (SDG 15.2) and mountain ecosystems (SDG 15.4), for example, and halting decline in biodiversity (SDG 15.5) in the Anthropocene requires a re-envisioning of how ecological models can best support the comprehensive assessments of biodiversity and its change that are required for successful action.
A key opportunity to advance ecological modeling for both predictive and explanatory purposes arises through a collaboration between ecologists and the Earth observation community, and a close integration of remote sensing and species distribution models. Remote sensing products have the capacity to provide continuous spatiotemporal information about key factors driving the distribution of organisms, therefore improving both the use and accuracy of these models for management and planning.
Here we first survey the literature on remote sensing data products available to ecological modelers interested in improving predictions of species range dynamics under global change. We specifically explore the key biophysical processes underlying the distribution of species in the Anthropocene including climate variability, changes in land cover, and disturbances. We then discuss potential synergies between the ecological modeling and remote sensing communities, and highlight opportunities to close the data and conceptual gaps that currently impede a more effective application of remote sensing for the monitoring and modeling of ecological systems. Specific attention is given to how potential collaborations between the two communities could lead to new opportunities to report on progress towards global agendas - such as the Agenda 2030 for sustainable development of the United Nations or the Post-2020 Global Biodiversity Framework of the Convention for Biological Diversity, and help guide conservation and management strategies towards sustainability.
•SDMs inform environmental interventions and policies towards achieving the SDGs.•RS helps fill data gaps and improve spatio-temporal transferability of projections.•Biodiversity monitoring in the Anthropocene needs close integration of RS in SDMs.•Joint ventures between the ecological modeling and RS communities are needed.
Forests mitigate climate change by sequestering large amounts of carbon (C). However, forest C storage is not permanent, and large pulses of tree mortality can thwart climate mitigation efforts. ...Forest pests are increasingly redistributed around the globe. Yet, the potential future impact of invasive alien pests on the forest C cycle remains uncertain. Here we show that large parts of Europe could be invaded by five detrimental alien pests already under current climate. Climate change increases the potential range of alien pests particularly in Northern and Eastern Europe. We estimate the live C at risk from a potential future invasion as 1027 Tg C (10% of the European total), with a C recovery time of 34 years. We show that the impact of introduced pests could be as severe as the current natural disturbance regime in Europe, calling for increased efforts to halt the introduction and spread of invasive alien species.
Land-use has transformed ecosystems over three quarters of the terrestrial surface, with massive repercussions on biodiversity. Land-use intensity is known to contribute to the effects of land-use on ...biodiversity, but the magnitude of this contribution remains uncertain. Here, we use a modified countryside species-area model to compute a global account of the impending biodiversity loss caused by current land-use patterns, explicitly addressing the role of land-use intensity based on two sets of intensity indicators. We find that land-use entails the loss of ~15% of terrestrial vertebrate species from the average 5 × 5 arcmin-landscape outside remaining wilderness areas and ~14% of their average native area-of-habitat, with a risk of global extinction for 556 individual species. Given the large fraction of global land currently used under low land-use intensity, we find its contribution to biodiversity loss to be substantial (~25%). While both sets of intensity indicators yield similar global average results, we find regional differences between them and discuss data gaps. Our results support calls for improved sustainable intensification strategies and demand-side actions to reduce trade-offs between food security and biodiversity conservation.
Mountain plant species shift their elevational ranges in response to climate change. However, to what degree these shifts lag behind current climate change, and to what extent delayed extinctions and ...colonizations contribute to these shifts, are under debate. Here, we calculate extinction debt and colonization credit of 135 species from the European Alps by comparing species distribution models with 1576 re-surveyed plots. We find extinction debt in 60% and colonization credit in 38% of the species, and at least one of the two in 93%. This suggests that the realized niche of very few of the 135 species fully tracks climate change. As expected, extinction debts occur below and colonization credits occur above the optimum elevation of species. Colonization credits are more frequent in warmth-demanding species from lower elevations with lower dispersal capability, and extinction debts are more frequent in cold-adapted species from the highest elevations. Local extinctions hence appear to be already pending for those species which have the least opportunity to escape climate warming.
To assess the geographical transferability of niche-based species distribution models fitted with two modelling techniques. Two distinct geographical study areas in Switzerland and Austria, in the ...subalpine and alpine belts. Generalized linear and generalized additive models (GLM and GAM) with a binomial probability distribution and a logit link were fitted for 54 plant species, based on topoclimatic predictor variables. These models were then evaluated quantitatively and used for spatially explicit predictions within (internal evaluation and prediction) and between (external evaluation and prediction) the two regions. Comparisons of evaluations and spatial predictions between regions and models were conducted in order to test if species and methods meet the criteria of full transferability. By full transferability, we mean that: (1) the internal evaluation of models fitted in region A and B must be similar; (2) a model fitted in region A must at least retain a comparable external evaluation when projected into region B, and vice-versa; and (3) internal and external spatial predictions have to match within both regions. The measures of model fit are, on average, 24% higher for GAMs than for GLMs in both regions. However, the differences between internal and external evaluations (AUC coefficient) are also higher for GAMs than for GLMs (a difference of 30% for models fitted in Switzerland and 54% for models fitted in Austria). Transferability, as measured with the AUC evaluation, fails for 68% of the species in Switzerland and 55% in Austria for GLMs (respectively for 67% and 53% of the species for GAMs). For both GAMs and GLMs, the agreement between internal and external predictions is rather weak on average (Kulczynski's coefficient in the range 0.3-0.4), but varies widely among individual species. The dominant pattern is an asymmetrical transferability between the two study regions (a mean decrease of 20% for the AUC coefficient when the models are transferred from Switzerland and 13% when they are transferred from Austria). The large inter-specific variability observed among the 54 study species underlines the need to consider more than a few species to test properly the transferability of species distribution models. The pronounced asymmetry in transferability between the two study regions may be due to peculiarities of these regions, such as differences in the ranges of environmental predictors or the varied impact of land-use history, or to species-specific reasons like differential phenotypic plasticity, existence of ecotypes or varied dependence on biotic interactions that are not properly incorporated into niche-based models. The lower variation between internal and external evaluation of GLMs compared to GAMs further suggests that overfitting may reduce transferability. Overall, a limited geographical transferability calls for caution when projecting niche-based models for assessing the fate of species in future environments.
Socioeconomic legacy yields an invasion debt Essl, Franz; Dullinger, Stefan; Rabitsch, Wolfgang ...
Proceedings of the National Academy of Sciences - PNAS,
01/2011, Letnik:
108, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Globalization and economic growth are widely recognized as important drivers of biological invasions. Consequently, there is an increasing need for governments to address the role of international ...trade in their strategies to prevent species introductions. However, many of the most problematic alien species are not recent arrivals but were introduced several decades ago. Hence, current patterns of alien-species richness may better reflect historical rather than contemporary human activities, a phenomenon which might be called "invasion debt." Here, we show that across 10 taxonomic groups (vascular plants, bryophytes, fungi, birds, mammals, reptiles, amphibians, fish, terrestrial insects, and aquatic invertebrates) in 28 European countries, current numbers of alien species established in the wild are indeed more closely related to indicators of socioeconomic activity from the year 1900 than to those from 2000, although the majority of species introductions occurred during the second half of the 20th century. The strength of the historical signal varies among taxonomic groups, with those possessing good capabilities for dispersal (birds, insects) more strongly associated with recent socioeconomic drivers. Nevertheless, our results suggest a considerable historical legacy for the majority of the taxa analyzed. The consequences of the current high levels of socioeconomic activity on the extent of biological invasions will thus probably not be completely realized until several decades into the future.
Aim: We introduce a high-quality global database of established alien amphibians and reptiles. We use this data set to analyse: (1) the global distribution; (2) the temporal dynamics; (3) the flows ...between native and alien ranges; and (4) the key drivers of established alien amphibians and reptiles. Location: Worldwide. Methods: We collected geographical records of established amphibians and reptiles from a thorough search across a wide number of sources. We supplemented these data with year of first record, when available. We used descriptive statistics and data visualization techniques to analyse taxonomic, spatial and temporal patterns in establishment records and the global flows of alien species. We used generalized linear mixed models to relate spatial variation in the number of established species richness with variables describing geographical, environmental and human factors. Results: Our database covers 86% of the terrestrial area of the world. We identified 78 alien amphibian and 198 alien reptile species established in at least one of our 359 study regions. These figures represent about 1.0% of the extant global amphibian and 1.9% of the extant global reptile species richness. The flows of amphibians were dominated by exchanges between and within North and South America, and within Europe (59% of all links). For reptiles, the network of global flows of established alien species was much more diverse, with every continental region being both a donor and a recipient of similar importance. The number of established alien amphibians and reptiles has grown slowly until 1950 and strongly increased thereafter. Our generalized linear mixed models revealed that insularity, climatic conditions, and socio-economic development significantly influenced the distributional patterns for both groups. Main conclusions: We conclude that biological invasions by alien amphibians and reptiles are a rapidly accelerating phenomenon, particularly on islands with heterogeneous climates of economically highly developed countries.
Aim Biodiversity responses to changing environmental forcing on species are often characterized by considerable time-lags (= relaxation times). Although changes to the occurrence and abundance of ...species likely have cascading effects (e.g. on species of other trophic levels, genes, community structure and ecosystem processes), current concepts addressing lagged biodiversity responses are limited to single drivers affecting a few biodiversity components (e.g. extinction debt in terms of species numbers or population size). Little attention has been paid to the interacting and cumulative nature of time-lag phenomena. Here, we synthesize current knowledge, mechanisms and implications of delayed biodiversity responses and propose a 'cumulative biodiversity lags-framework' which aims to integrate lagged responses of various components of biological organization. Location Global. Results Effects of change in environmental forcing are transmitted along a series of linked cause–effect relationships which act on different biodiversity components (e.g. individuals, populations, species, communities). We show that lagged responses to environmental forcing are caused by different mechanisms (e.g. metapopulation dynamics, dispersal limitation, successional dynamics), which operate sequentially on these intermediary links. Lags manifest themselves on the respective biodiversity component which changes over time; the full relaxation time of a focal system will therefore depend on the aggregate length of different lags. We elucidate key mechanisms and circumstances which are likely to cause cumulative lagged responses, and propose research avenues to improve understanding of cumulative biodiversity lags. Main conclusions The failure to give adequate consideration to widespread cumulative time-lags often masks the full extent of biodiversity changes that have already been triggered. Effects that are particularly relevant for human livelihoods (e.g. changes in the provision of ecosystem services) may emerge with the most pronounced delay. Accordingly, the consideration of appropriate temporal scales should become a key topic in future work at the science–policy interface.
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