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Of Asian forests and European fields: Eastern U.S. plant invasions in a global floristic context.

Fridley JD - PLoS ONE (2008)

Bottom Line: In contrast, EUS invasive species are most likely to come from East Asia (29%), a pattern that is magnified when the invasive pool is restricted to species that are native to a single floristic region (25% from East Asia, compared to only 11% from northern/central Europe and 2% from the Mediterranean).Moreover, East Asian invaders are mostly woody (56%, compared to just 23% of the total alien flora) and are significantly more likely to invade intact forests and riparian areas than European species, which dominate managed or disturbed ecosystems.This view must be superseded by a biogeographic invasion theory that is explicitly habitat-specific and can explain why particular world biotas tend to dominate particular environments.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Syracuse University, Syracuse, New York, USA. fridley@syr.edu

ABSTRACT

Background: Biogeographic patterns of species invasions hold important clues to solving the recalcitrant 'who', 'where', and 'why' questions of invasion biology, but the few existing studies make no attempt to distinguish alien floras (all non-native occurrences) from invasive floras (rapidly spreading species of significant management concern), nor have invasion biologists asked whether particular habitats are consistently invaded by species from particular regions.

Methodology/principal findings: Here I describe the native floristic provenances of the 2629 alien plant taxa of the Eastern Deciduous Forest of the Eastern U.S. (EUS), and contrast these to the subset of 449 taxa that EUS management agencies have labeled 'invasive'. Although EUS alien plants come from all global floristic regions, nearly half (45%) have native ranges that include central and northern Europe or the Mediterranean (39%). In contrast, EUS invasive species are most likely to come from East Asia (29%), a pattern that is magnified when the invasive pool is restricted to species that are native to a single floristic region (25% from East Asia, compared to only 11% from northern/central Europe and 2% from the Mediterranean). Moreover, East Asian invaders are mostly woody (56%, compared to just 23% of the total alien flora) and are significantly more likely to invade intact forests and riparian areas than European species, which dominate managed or disturbed ecosystems.

Conclusions/significance: These patterns suggest that the often-invoked 'imperialist dogma' view of global invasions equating invasion events with the spread of European colonialism is at best a restricted framework for invasion in disturbed ecosystems. This view must be superseded by a biogeographic invasion theory that is explicitly habitat-specific and can explain why particular world biotas tend to dominate particular environments.

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Related in: MedlinePlus

Floristic regions of the world, from Takhtajan [27].Region names and associated statistics are listed in Tables 2 and 3. Those shown here do not include several largely oceanic or archipelagic regions ignored in the present analysis.
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pone-0003630-g001: Floristic regions of the world, from Takhtajan [27].Region names and associated statistics are listed in Tables 2 and 3. Those shown here do not include several largely oceanic or archipelagic regions ignored in the present analysis.

Mentions: In this paper I analyze the alien and invasive vascular floras of the EUS coincident with the Eastern Deciduous Forest biome of North America [26] to determine whether alien and invasive plant species of this region are more likely to come from particular source floras, using the Takhtajan [27] global floristic regions as source areas that correspond to global centers of plant diversification (Fig. 1). Due to the prevailing view that strategies for plant success depend strongly on habitat qualities, which in turn suggests that global floras should preferentially contribute species to certain habitats, I conducted the analysis for invasive species using a habitat classification (Table 1) based on environmental differences that select for well known differences in plant strategies (disturbance regime and resource availability [25]). Two plant strategies associated with habitat type that are widely available for floristic-based analyses include species growth form (trees, forbs, etc.) and duration (annual, biennial, perennial); for these attributes I also asked whether native, alien, and invasive components of the EUS flora exhibit regular differences in attribute composition associated with floristic and habitat patterns. The primary objective of this study was to address whether modern plant invasions are qualitatively any different from biotic interchanges throughout the history of biotic migrations [4], [5], [28]—that is, whether biogeographic patterns of modern invasions reveal new evolutionary-based insights that provide a general framework for predicting where invaders come from and which areas are preferentially invaded.


Of Asian forests and European fields: Eastern U.S. plant invasions in a global floristic context.

Fridley JD - PLoS ONE (2008)

Floristic regions of the world, from Takhtajan [27].Region names and associated statistics are listed in Tables 2 and 3. Those shown here do not include several largely oceanic or archipelagic regions ignored in the present analysis.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2572842&req=5

pone-0003630-g001: Floristic regions of the world, from Takhtajan [27].Region names and associated statistics are listed in Tables 2 and 3. Those shown here do not include several largely oceanic or archipelagic regions ignored in the present analysis.
Mentions: In this paper I analyze the alien and invasive vascular floras of the EUS coincident with the Eastern Deciduous Forest biome of North America [26] to determine whether alien and invasive plant species of this region are more likely to come from particular source floras, using the Takhtajan [27] global floristic regions as source areas that correspond to global centers of plant diversification (Fig. 1). Due to the prevailing view that strategies for plant success depend strongly on habitat qualities, which in turn suggests that global floras should preferentially contribute species to certain habitats, I conducted the analysis for invasive species using a habitat classification (Table 1) based on environmental differences that select for well known differences in plant strategies (disturbance regime and resource availability [25]). Two plant strategies associated with habitat type that are widely available for floristic-based analyses include species growth form (trees, forbs, etc.) and duration (annual, biennial, perennial); for these attributes I also asked whether native, alien, and invasive components of the EUS flora exhibit regular differences in attribute composition associated with floristic and habitat patterns. The primary objective of this study was to address whether modern plant invasions are qualitatively any different from biotic interchanges throughout the history of biotic migrations [4], [5], [28]—that is, whether biogeographic patterns of modern invasions reveal new evolutionary-based insights that provide a general framework for predicting where invaders come from and which areas are preferentially invaded.

Bottom Line: In contrast, EUS invasive species are most likely to come from East Asia (29%), a pattern that is magnified when the invasive pool is restricted to species that are native to a single floristic region (25% from East Asia, compared to only 11% from northern/central Europe and 2% from the Mediterranean).Moreover, East Asian invaders are mostly woody (56%, compared to just 23% of the total alien flora) and are significantly more likely to invade intact forests and riparian areas than European species, which dominate managed or disturbed ecosystems.This view must be superseded by a biogeographic invasion theory that is explicitly habitat-specific and can explain why particular world biotas tend to dominate particular environments.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Syracuse University, Syracuse, New York, USA. fridley@syr.edu

ABSTRACT

Background: Biogeographic patterns of species invasions hold important clues to solving the recalcitrant 'who', 'where', and 'why' questions of invasion biology, but the few existing studies make no attempt to distinguish alien floras (all non-native occurrences) from invasive floras (rapidly spreading species of significant management concern), nor have invasion biologists asked whether particular habitats are consistently invaded by species from particular regions.

Methodology/principal findings: Here I describe the native floristic provenances of the 2629 alien plant taxa of the Eastern Deciduous Forest of the Eastern U.S. (EUS), and contrast these to the subset of 449 taxa that EUS management agencies have labeled 'invasive'. Although EUS alien plants come from all global floristic regions, nearly half (45%) have native ranges that include central and northern Europe or the Mediterranean (39%). In contrast, EUS invasive species are most likely to come from East Asia (29%), a pattern that is magnified when the invasive pool is restricted to species that are native to a single floristic region (25% from East Asia, compared to only 11% from northern/central Europe and 2% from the Mediterranean). Moreover, East Asian invaders are mostly woody (56%, compared to just 23% of the total alien flora) and are significantly more likely to invade intact forests and riparian areas than European species, which dominate managed or disturbed ecosystems.

Conclusions/significance: These patterns suggest that the often-invoked 'imperialist dogma' view of global invasions equating invasion events with the spread of European colonialism is at best a restricted framework for invasion in disturbed ecosystems. This view must be superseded by a biogeographic invasion theory that is explicitly habitat-specific and can explain why particular world biotas tend to dominate particular environments.

Show MeSH
Related in: MedlinePlus