Browsing by Author "Dullinger, Stefan"
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- Biogeography and global flows of 100 major alien fungal and fungus-like oomycete pathogensPublication . Schertler, Anna; Lenzner, Bernd; Dullinger, Stefan; Moser, Dietmar; Bufford, Jennifer L.; Ghelardini, Luisa; Santini, Alberto; Capinha, César; Monteiro, Miguel; Reino, Luís; Wingfield, Michael J.; Seebens, Hanno; Thines, Marco; Wayne Dawson, Wayne Dawson; Kleunen, Mark van; Kreft, Holger; Pergl, Jan; Pyšek, Petr; Weigelt, Patrick; Winter, Marten; Essl, FranzAim: Spreading infectious diseases associated with introduced pathogens can have devastating effects on native biota and human livelihoods. We analyse the global distribution of 100 major alien fungal and oomycete pathogens with substantial socio-economic and environmental impacts and examine their taxonomy, ecological characteristics, temporal accumulation trajectories, regional hot- and coldspots of taxon richness and taxon flows between continents. Location: Global. Taxon: Alien/cryptogenic fungi and fungus-like oomycetes, pathogenic to plants or animals. Methods: To identify over/underrepresented classes and phyla, we performed Chi2 tests of independence. To describe spatial patterns, we calculated the region-wise richness and identified hot- and coldspots, defined as residuals after correcting taxon richness for region area and sampling effort via a quasi-Poisson regression. We examined the relationship with environmental and socio-economic drivers with a multiple linear regression and evaluated a potential island effect. Regional first records were pooled over 20-year periods, and for global flows the links between the native range to the alien regions were mapped. Results: Peronosporomycetes (Oomycota) were overrepresented among taxa and regional taxon richness was positively correlated with area and sampling effort. While no island effect was found, likely due to host limitations, hotspots were correlated with human modification of terrestrial land, per capita gross domestic product, temperate and tropical forest biomes, and orobiomes. Regional first records have increased steeply in recent decades. While Europe and Northern America were major recipients, about half of the taxa originate from Asia. Main Conclusions: We highlight the putative importance of anthropogenic drivers, such as land use providing a conducive environment, contact opportunities and susceptible hosts, as well as economic wealth likely increasing colonisation pressure. While most taxa were associated with socio-economic impacts, possibly partly due to a bias in research focus, about a third show substantial impacts to both socio-economy and the environment, underscoring the importance of maintaining a wholescale perspective across natural and managed systems.
- Biogeography and global flows of 100 major alien fungal and fungus‐like oomycete pathogensPublication . Schertler, Anna; Lenzner, Bernd; Dullinger, Stefan; Moser, Dietmar; Bufford, Jennifer L.; Ghelardini, Luisa; Santini, Alberto; Capinha, César; Monteiro, Miguel; Reino, Luís; Wingfield, Michael J.; Seebens, Hanno; Thines, Marco; Dawson, Wayne; van Kleunen, Mark; Kreft, Holger; Pergl, Jan; Pyšek, Petr; Weigelt, Patrick; Winter, Marten; Essl, FranzAim: Spreading infectious diseases associated with introduced pathogens can have devastating effects on native biota and human livelihoods. We analyse the global distribution of 100 major alien fungal and oomycete pathogens with substantial socio-economic and environmental impacts and examine their taxonomy, ecological characteristics, temporal accumulation trajectories, regional hot- and coldspots of taxon richness and taxon flows between continents. Location: Global. Taxon: Alien/cryptogenic fungi and fungus-like oomycetes, pathogenic to plants or animals. Methods: To identify over/underrepresented classes and phyla, we performed Chi2 tests of independence. To describe spatial patterns, we calculated the region-wise richness and identified hot- and coldspots, defined as residuals after correcting taxon richness for region area and sampling effort via a quasi-Poisson regression. We examined the relationship with environmental and socio-economic drivers with a multiple linear regression and evaluated a potential island effect. Regional first records were pooled over 20-year periods, and for global flows the links between the native range to the alien regions were mapped. Results: Peronosporomycetes (Oomycota) were overrepresented among taxa and regional taxon richness was positively correlated with area and sampling effort. While no island effect was found, likely due to host limitations, hotspots were correlated with human modification of terrestrial land, per capita gross domestic product, temperate and tropical forest biomes, and orobiomes. Regional first records have increased steeply in recent decades. While Europe and Northern America were major recipients, about half of the taxa originate from Asia.Main Conclusions: We highlight the putative importance of anthropogenic drivers, such as land use providing a conducive environment, contact opportunities and susceptible hosts, as well as economic wealth likely increasing colonisation pressure. While most taxa were associated with socio-economic impacts, possibly partly due to a bias in research focus, about a third show substantial impacts to both socio-economy and the environment, underscoring the importance of maintaining a wholescale perspective across natural and managed systems.
- Drivers of future alien species impacts: an expert‐based assessmentPublication . Essl, Franz; Lenzner, Bernd; Bacher, Sven; Bailey, Sarah; Capinha, César; Daehler, Curtis; Dullinger, Stefan; Genovesi, Piero; Hui, Cang; Hulme, Philip E.; Jeschke, Jonathan M.; Katsanevakis, Stelios; Kühn, Ingolf; Leung, Brian; Liebhold, Andrew; Liu, Chunlong; MacIsaac, Hugh J.; Meyerson, Laura A.; Nuñez, Martin A.; Pauchard, Aníbal; Pyšek, Petr; Rabitsch, Wolfgang; Richardson, David M.; Roy, Helen E.; Ruiz, Gregory M.; Russell, James C.; Sanders, Nathan J.; Sax, Dov F.; Scalera, Riccardo; Seebens, Hanno; Springborn, Michael; Turbelin, Anna; Kleunen, Mark; Holle, Betsy; Winter, Marten; Zenni, Rafael D.; Mattsson, Brady J.; Roura‐Pascual, NuriaUnderstanding the likely future impacts of biological invasions is crucial yet highly challenging given the multiple relevant environmental, socio-economic and societal contexts and drivers. In the absence of quantitative models, methods based on expert knowledge are the best option for assessing future invasion trajectories. Here, we present an expert assessment of the drivers of potential alien species impacts under contrasting scenarios and socioecological contexts through the mid-21st century. Based on responses from 36 experts in biological invasions, moderate (20%-30%) increases in invasions, compared to the current conditions, are expected to cause major impacts on biodiversity in most socioecological contexts. Three main drivers of biological invasions-transport, climate change and socio-economic change-were predicted to significantly affect future impacts of alien species on biodiversity even under a best-case scenario. Other drivers (e.g. human demography and migration in tropical and subtropical regions) were also of high importance in specific global contexts (e.g. for individual taxonomic groups or biomes). We show that some best-case scenarios can substantially reduce potential future impacts of biological invasions. However, rapid and comprehensive actions are necessary to use this potential and achieve the goals of the Post-2020 Framework of the Convention on Biological Diversity.
- Grassland vegetation height affects bird responses to forest edges in Mediterranean open farmlandPublication . Faria, João; Reino, Luís; Beja, Pedro; Gonçalves, David; Sánchez-Oliver, Juan S.; Moreira, Francisco; Catry, Inês; Rotenberry, John T.; Morgado, Rui; Brotons, Lluís; Dullinger, Stefan; Schindler, Stefan; Santana, JoanaAfforestation affects Mediterranean farmland biodiversity due to loss and fragmentation of grassland habitats. While the influence of landscape context and plantation edges on farmland bird responses to afforestation is well-documented, less is known about the influence of grassland vegetation height and how it interacts with afforestation to influence bird communities. Here, we examined how changes in grassland vegetation height affect bird responses to afforestation in a farmland region in southern Portugal, and how these are affected by plantation type and edge. This region has experienced afforestation with eucalyptus, pine and oak stands, agricultural intensification, and frequent dry periods. To capture local and landscape-level changes, we collected data in two periods (2005 and 2014–15). Grassland vegetation height varied between sampling periods, emerging as a key factor affecting changes observed. Ground-nesting and cereal-associated species increased in abundance with taller vegetation in 2014–15, while in 2005, with drier weather and shorter vegetation, the species associated with ploughed fields were more abundant. Vegetation height effects on bird assemblages depended on plantation type and distance to plantation edges. Farmland bird abundance, including ground-nesting and cereal crops-associated species, increased with taller vegetation, particularly near oak and pine plantations. Conversely, species associated with ploughed fields declined with taller vegetation, especially near eucalyptus plantations. Results highlight complex interactions between vegetation height, plantation type, and edge proximity shaping avian assemblages. This study supports the importance of field and landscape-level management with special focus on grassland vegetation height and landscape heterogeneity for preserving open-farmland birds in fast-changing Mediterranean farmland landscapes.
- Potential sources of time lags in calibrating species distribution modelsPublication . Essl, Franz; García‐Rodríguez, Adrián; Lenzner, Bernd; Alexander, Jake M.; Capinha, César; Gaüzère, Pierre; Guisan, Antoine; Kühn, Ingolf; Lenoir, Jonathan; Richardson, David M.; Rumpf, Sabine B.; Svenning, Jens‐Christian; Thuiller, Wilfried; Zurell, Damaris; Dullinger, StefanThe Anthropocene is characterized by a rapid pace of environmental change and is causing a multitude of biotic responses, including those that affect the spatial distribution of species. Lagged responses are frequent and species distributions and assemblages are consequently pushed into a disequilibrium state. How the characteristics of environmental change—for example, gradual ‘press’ disturbances such as rising temperatures due to climate change versus infrequent ‘pulse’ disturbances such as extreme events—affect the magnitude of responses and the relaxation times of biota has been insufficiently explored. It is also not well understood how widely used approaches to assess or project the responses of species to changing environmental conditions can deal with time lags. It, therefore, remains unclear to what extent time lags in species distributions are accounted for in biodiversity assessments, scenarios and models; this has ramifications for policymaking and conservation science alike. This perspective piece reflects on lagged species responses to environmental change and discusses the potential consequences for species distribution models (SDMs), the tools of choice in biodiversity modelling. We suggest ways to better account for time lags in calibrating these models and to reduce their leverage effects in projections for improved biodiversity science and policy.
- Projecting the continental accumulation of alien species through to 2050Publication . Seebens, Hanno; Bacher, Sven; Blackburn, Tim M.; Capinha, César; Dawson, Wayne; Dullinger, Stefan; Genovesi, Piero; Hulme, Philip E.; Kleunen, Mark; Kühn, Ingolf; Jeschke, Jonathan M.; Lenzner, Bernd; Liebhold, Andrew M.; Pattison, Zarah; Pergl, Jan; Pyšek, Petr; Winter, Marten; Essl, FranzBiological invasions have steadily increased over recent centuries. However, we still lack a clear expectation about future trends in alien species numbers. In particular, we do not know whether alien species will continue to accumulate in regional floras and faunas, or whether the pace of accumulation will decrease due to the depletion of native source pools. Here, we apply a new model to simulate future numbers of alien species based on estimated sizes of source pools and dynamics of historical invasions, assuming a continuation of processes in the future as observed in the past (a business-as-usual scenario). We first validated performance of different model versions by conducting a back-casting approach, therefore fitting the model to alien species numbers until 1950 and validating predictions on trends from 1950 to 2005. In a second step, we selected the best performing model that provided the most robust predictions to project trajectories of alien species numbers until 2050. Altogether, this resulted in 3,790 stochastic simulation runs for 38 taxon-continent combinations. We provide the first quantitative projections of future trajectories of alien species numbers for seven major taxonomic groups in eight continents, accounting for variation in sampling intensity and uncertainty in projections. Overall, established alien species numbers per continent were predicted to increase from 2005 to 2050 by 36%. Particularly, strong increases were projected for Europe in absolute (+2,543 ± 237 alien species) and relative terms, followed by Temperate Asia (+1,597 ± 197), Northern America (1,484 ± 74) and Southern America (1,391 ± 258). Among individual taxonomic groups, especially strong increases were projected for invertebrates globally. Declining (but still positive) rates were projected only for Australasia. Our projections provide a first baseline for the assessment of future developments of biological invasions, which will help to inform policies to contain the spread of alien species.
- Regional invasion history and land use shape the prevalence of non‐native species in local assemblagesPublication . Liu, Daijun; Essl, Franz; Lenzner, Bernd; Moser, Dietmar; Semenchuk, Philipp; Blackburn, Tim M.; Cassey, Phillip; Biancolini, Dino; Capinha, César; Dawson, Wayne; Dyer, Ellie E.; Guénard, Benoit; Economo, Evan P.; Kreft, Holger; Pergl, Jan; Pyšek, Petr; van Kleunen, Mark; Rondinini, Carlo; Seebens, Hanno; Weigelt, Patrick; Winter, Marten; Purvis, Andy; Dullinger, StefanThe ecological impact of non-native species arises from their establishment in local assemblages. However, the rates of non-native spread in new regions and their determinants have not been comprehensively studied. Here, we combined global databases documenting the occurrence of non-native species and residence of non-native birds, mammals, and vascular plants at regional and local scales to describe how the likelihood of non-native occurrence and their proportion in local assemblages relate with their residence time and levels of human usage in different ecosystems. Our findings reveal that local non-native occurrence generally increases with residence time. Colonization is most rapid in croplands and urban areas, while it is slower and variable in natural or semi-natural ecosystems. Notably, non-native occurrence continues to rise even 200 years after introduction, especially for birds and vascular plants, and in other land-use types rather than croplands and urban areas. The impact of residence time on non-native proportions is significant only for mammals. We conclude that the continental exchange of biotas requires considerable time for effects to manifest at the local scale across taxa and land-use types. The unpredictability of future impacts, implied by the slow spread of non-native species, strengthens the call for stronger regulations on the exchange of non-native species to reduce the long-lasting invasion debt looming on ecosystems' future.
- Snapshot isolation and isolation history challenge the analogy between mountains and islands used to understand endemismPublication . Flantua, Suzette G. A.; Payne, Davnah; Borregaard, Michael K.; Beierkuhnlein, Carl; Steinbauer, Manuel J.; Dullinger, Stefan; Essl, Franz; Irl, Severin D. H.; Kienle, David; Kreft, Holger; Lenzner, Bernd; Norder, Sietze J.; Rijsdijk, Kenneth F.; Rumpf, Sabine B.; Weigelt, Patrick; Field, RichardAim Mountains and islands are both well known for their high endemism. To explain this similarity, parallels have been drawn between the insularity of “true islands” (land surrounded by water) and the isolation of habitats within mountains (so‐called “mountain islands”). However, parallels rarely go much beyond the observation that mountaintops are isolated from one another, as are true islands. Here, we challenge the analogy between mountains and true islands by re‐evaluating the literature, focusing on isolation (the prime mechanism underlying species endemism by restricting gene flow) from a dynamic perspective over space and time. Framework We base our conceptualization of “isolation” on the arguments that no biological system is completely isolated; instead, isolation has multiple spatial and temporal dimensions relating to biological and environmental processes. We distinguish four key dimensions of isolation: (a) environmental difference from surroundings; (b) geographical distance to equivalent environment [points (a) and (b) are combined as “snapshot isolation”]; (c) continuity of isolation in space and time; and (d) total time over which isolation has been present [points (c) and (d) are combined as “isolation history”]. We evaluate the importance of each dimension in different types of mountains and true islands, demonstrating that substantial differences exist in the nature of isolation between and within each type. In particular, different types differ in their initial isolation and in the dynamic trajectories they follow, with distinct phases of varying isolation that interact with species traits over time to form present‐day patterns of endemism. Conclusions Our spatio‐temporal definition of isolation suggests that the analogy between true islands and mountain islands masks important variation of isolation over long time‐scales. Our understanding of endemism in isolated systems can be greatly enriched if the dynamic spatio‐temporal dimensions of isolation enter models as explanatory variables and if these models account for the trajectories of the history of a system.
- The global distribution patterns of alien vertebrate richness in mountainsPublication . García-Rodríguez, Adrián; Lenzner, Bernd; Velasco, Julián A.; Schertler, Anna; Omer, Ali; Seebens, Hanno; Capinha, César; Gallardo, Belinda; Dullinger, Stefan; Essl, FranzThe diverse biotas of the world’s mountains face a challenging future due to increasing threats like climate change, land-use change, and biological invasions, the last being particularly understudied in these regions. Here we compile occurrence records for 717 alien vertebrate species distributed in 2984 mountains worldwide. We analyze their distribution, biogeographic origin, presence in protected areas, and the drivers’ explaining alien vertebrate richness in mountains. We find that the alien vertebrates most frequently recorded are birds (318 species) and mammals (161 species) reported in 2595 and 1518 mountains globally, respectively. The Palearctic, Nearctic, and Australasian realms are the most common recipients; the Nearctic, Indo-Malay, and Afrotropic realms are the most frequent donors. Almost 50% of the alien species studied also occur in protected areas. Proxies of anthropogenic impacts (e.g., higher road density or lower biodiversity intactness) and mountains’ physical characteristics (e.g., elevation range and roughness) explain the distribution of alien vertebrates in mountains. Importantly, the magnitude of invasions in tropical mountains could be underestimated due to sampling bias towards the Northern Hemisphere and Australia. Our large-scale assessment reveals the advance of alien vertebrates in mountains worldwide and urges attention to minimize the impacts of biological invasions on the exceptional mountain biotas.
- The impact of land use on non-native species incidence and number in local assemblages worldwidePublication . Liu, Daijun; Semenchuk, Philipp; Essl, Franz; Lenzner, Bernd; Moser, Dietmar; Blackburn, Tim M.; Cassey, Phillip; Biancolini, Dino; Capinha, César; Dawson, Wayne; Dyer, Ellie E.; Guénard, Benoit; Economo, Evan P.; Kreft, Holger; Pergl, Jan; Pyšek, Petr; van Kleunen, Mark; Nentwig, Wolfgang; Rondinini, Carlo; Seebens, Hanno; Weigelt, Patrick; Winter, Marten; Purvis, Andy; Dullinger, StefanWhile the regional distribution of non-native species is increasingly well documented for some taxa, global analyses of non-native species in local assemblages are still missing. Here, we use a worldwide collection of assemblages from five taxa - ants, birds, mammals, spiders and vascular plants - to assess whether the incidence, frequency and proportions of naturalised nonnative species depend on type and intensity of land use. In plants, assemblages of primary vegetation are least invaded. In the other taxa, primary vegetation is among the least invaded land-use types, but one or several other types have equally low levels of occurrence, frequency and proportions of non-native species. High land use intensity is associated with higher non-native incidence and frequency in primary vegetation, while intensity effects are inconsistent for other land-use types. These findings highlight the potential dual role of unused primary vegetation in preserving native biodiversity and in conferring resistance against biological invasions.