Browsing by Author "Kreft, Holger"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- 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.
- 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 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.