Dataset Information

Invasion intensity influences scale-dependent effects of an exotic species on native plant diversity.

ABSTRACT: Invasive plant species reduce the diversity of natives by altering habitats or disturbance regimes, but it is less clear whether they do so via competitive exclusion. Here, we show that invader abundance alters scale-dependent competitive effects of invasion on native plant richness. Large-seeded exotic annual Erodium cicutarium invaded a site that manipulated rodent granivores. The invader became dominant on all plots but attained its highest abundance on plots that removed rodents. Invasion reduced plant abundance but not evenness; site-wide richness did not change over time on control plots but declined significantly on rodent removal plots. Species-area relationships within plots changed differently with invasion intensity: slopes increased and y-intercepts decreased on control plots relative to rodent removal plots. Changes in species-area slopes and y-intercepts following invasion suggest that common rather than rare species were most strongly impacted at small spatial scales on control plots, while common and rare species were both negatively impacted at all spatial scales on rodent removal plots. Small-seeded species declined in abundance following invasion more so than large-seeded species, indicative of competitive interactions mediated by seed size. These results reveal variation in scale-dependent competitive effects of invasion on native richness associated with invasion intensity.

SUBMITTER: Valone TJ

PROVIDER: S-EPMC6904574 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Invasion intensity influences scale-dependent effects of an exotic species on native plant diversity.

Valone Thomas J TJ Weyers David P DP

Scientific reports 20191210 1

Invasive plant species reduce the diversity of natives by altering habitats or disturbance regimes, but it is less clear whether they do so via competitive exclusion. Here, we show that invader abundance alters scale-dependent competitive effects of invasion on native plant richness. Large-seeded exotic annual Erodium cicutarium invaded a site that manipulated rodent granivores. The invader became dominant on all plots but attained its highest abundance on plots that removed rodents. Invasion re ...[more]

PMID: 31822718

Similar Datasets

Project description:Functional diversity metrics are increasingly used to augment or replace taxonomic diversity metrics to deliver more mechanistic insights into community structure and function. Metrics used to describe landscape structure and characteristics share many of the same limitations as taxonomy-based metrics, particularly their reliance on anthropogenically defined typologies with little consideration of structure, management, or function. However, the development of alternative metrics to describe landscape characteristics has been limited. Here, we extend the functional diversity framework to characterize landscapes based on the diversity of resources available across habitats present. We then examine the influence of resource diversity and provenance on the functional diversities of native and exotic avian communities in New Zealand. Invasive species are increasingly prevalent and considered a global threat to ecosystem function, but the characteristics of and interactions between sympatric native and exotic communities remain unresolved. Understanding their comparative responses to environmental change and the mechanisms underpinning them is of growing importance in predicting community dynamics and changing ecosystem function. We use (i) matrices of resource use (species) and resource availability (habitats) and (ii) occurrence data for 62 native and 25 exotic species and 19 native and 13 exotic habitats in 2015 10 × 10 km quadrats to examine the relationship between native and exotic avian and landscape functional diversity. The numbers of species in, and functional diversities of, native and exotic communities were positively related. Each community displayed evidence of environmental filtering, but it was significantly stronger for exotic species. Less environmental filtering occurred in landscapes providing a more diverse combination of resources, with resource provenance also an influential factor. Landscape functional diversity explained a greater proportion of variance in native and exotic community characteristics than the number of habitat types present. Resource diversity and provenance should be explicitly accounted for when characterizing landscape structure and change as they offer additional mechanistic understanding of the links between environmental filtering and community structure. Manipulating resource diversity through the design and implementation of management actions could prove a powerful tool for the delivery of conservation objectives, be they to protect native species, control exotic species, or maintain ecosystem service provision.

Project description:Support for the "biotic resistance hypothesis," that species-rich communities are more successful at resisting invasion by exotic species than are species-poor communities, has long been debated. It has been argued that native-exotic richness relationships (NERR) are negative at small spatial scales and positive at large scales, but evidence for the role of spatial scale on NERR has been contradictory. However, no formal quantitative synthesis has previously examined whether NERR is scale-dependent across multiple studies, and previous studies on NERR have not distinguished spatial grain and extent, which may drive very different ecological processes. We used a global systematic review and hierarchical mixed-effects meta-analysis to provide a comprehensive quantitative assessment of the patterns of NERR over a range of spatial grain sizes and spatial extents, based on 204 individual cases of observational (non-experimental) NERRs from 101 publications. We show that NERR was indeed highly scale dependent across studies and increased with the log of grain size. However, mean NERR was not negative at any grain size, although there was high heterogeneity at small grain sizes. We found no clear patterns of NERR across different spatial extents, suggesting that extent plays a less important role in determining NERR than does grain, although there was a complex interaction between extent and grain size. Almost all studies on NERR were conducted in North America, western Europe, and a few other regions, with little information on tropical or Arctic regions. We did find that NERR increased northward in temperate regions and also varied with longitude. We discuss possible explanations for the patterns we found, and caution that our results do not show that invasive species are benign or have no negative consequences for biodiversity preservation. This study represents the first global quantitative analysis of scale-based NERR, and casts doubt on the existence of an "invasion paradox" of negative NERR at small scales and positive correlations at large scales in non-experimental studies.

Dataset Information

Invasion intensity influences scale-dependent effects of an exotic species on native plant diversity.

Publications

Invasion intensity influences scale-dependent effects of an exotic species on native plant diversity.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets