Dataset Information

Disentangling the abundance-impact relationship for invasive species.

ABSTRACT: To predict the threat of biological invasions to native species, it is critical that we understand how increasing abundance of invasive alien species (IAS) affects native populations and communities. The form of this relationship across taxa and ecosystems is unknown, but is expected to depend strongly on the trophic position of the IAS relative to the native species. Using a global metaanalysis based on 1,258 empirical studies presented in 201 scientific publications, we assessed the shape, direction, and strength of native responses to increasing invader abundance. We also tested how native responses varied with relative trophic position and for responses at the population vs. community levels. As IAS abundance increased, native populations declined nonlinearly by 20%, on average, and community metrics declined linearly by 25%. When at higher trophic levels, invaders tended to cause a strong, nonlinear decline in native populations and communities, with the greatest impacts occurring at low invader abundance. In contrast, invaders at the same trophic level tended to cause a linear decline in native populations and communities, while invaders at lower trophic levels had no consistent impacts. At the community level, increasing invader abundance had significantly larger effects on species evenness and diversity than on species richness. Our results show that native responses to invasion depend critically on invasive species' abundance and trophic position. Further, these general abundance-impact relationships reveal how IAS impacts are likely to develop during the invasion process and when to best manage them.

SUBMITTER: Bradley BA

PROVIDER: S-EPMC6525518 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Disentangling the abundance-impact relationship for invasive species.

Bradley Bethany A BA Laginhas Brittany B BB Whitlock Raj R Allen Jenica M JM Bates Amanda E AE Bernatchez Genevieve G Diez Jeffrey M JM Early Regan R Lenoir Jonathan J Vilà Montserrat M Sorte Cascade J B CJB

Proceedings of the National Academy of Sciences of the United States of America 20190429 20

To predict the threat of biological invasions to native species, it is critical that we understand how increasing abundance of invasive alien species (IAS) affects native populations and communities. The form of this relationship across taxa and ecosystems is unknown, but is expected to depend strongly on the trophic position of the IAS relative to the native species. Using a global metaanalysis based on 1,258 empirical studies presented in 201 scientific publications, we assessed the shape, dir ...[more]

PMID: 31036667

Similar Datasets

Project description:As a transitional vegetation type between evergreen broadleaved forest and deciduous broadleaved forest, evergreen-deciduous broadleaved mixed forest is composed of diverse plant species. This distinctive forest is generally distributed in mountainous areas with complex landforms and heterogeneous microenvironments. However, little is known about the roles of environmental conditions in driving the species diversity patterns of this forest. Here, based on a 15-ha plot in central China, we aimed to understand how and to what extent topographical characteristics and soil nutrients regulate the number and relative abundance of tree species in this forest. We measured environmental factors (terrain convexity, slope, soil total nitrogen, and phosphorus concentrations) and species diversity (species abundance distribution and species richness) in 20 m × 20 m subplots. Species abundance distribution was characterized by skewness, Berger-Parker index, and the proportion of singletons. The generalized additive model was used to examine the variations in diversity patterns caused by environmental factors. The structural equation model was used to assess whether and how topographical characteristics regulate species diversity via soil nutrients. We found that soil nutrients had significant negative effects on species richness and positive effects on all metrics of species abundance distribution. Convexity had significant positive effects on species richness and negative effects on all metrics of species abundance distribution, but these effects were mostly mediated by soil nutrients. Slope had significant negative effects on skewness and the Berger-Parker index, and these effects were almost independent of soil nutrients. Soil nutrients and topographical characteristics together accounted for 9.5-17.1% of variations in diversity patterns and, respectively, accounted for 8.9-13.9% and 3.3-10.7% of the variations. We concluded that soil nutrients were more important than topographical factors in regulating species diversity. Increased soil nutrient concentration led to decreased taxonomic diversity and increased species dominance and rarity. Convexity could be a better proxy for soil nutrients than slope. Moreover, these abiotic factors played limited roles in regulating diversity patterns, and it is possible that the observed patterns are also driven by some biotic and abiotic factors not considered here.

Project description:Aim:Understanding the drivers of the structure of coral reef fish assemblages is vital for their future conservation. Quantifying the separate roles of natural drivers from the increasing influence of anthropogenic factors, such as fishing and climate change, is a key component of this understanding. It follows that the intrinsic role of historical biogeographical and geomorphological factors must be accounted for when trying to understand the effects of contemporary disturbances such as fishing. Location:Comoros, Madagascar, Mozambique and Tanzania, Western Indian Ocean (WIO). Methods:We modeled patterns in the density and biomass of an assemblage of reef-associated fish species from 11 families, and their association with 16 biophysical variables. Results:Canonical analysis of principal coordinates revealed strong country affiliations of reef fish assemblages and distance-based linear modeling confirmed geographic location and reef geomorphology were the most significant correlates, explaining 32% of the observed variation in fish assemblage structure. Another 6%-8% of variation was explained by productivity gradients (chl_a), and reef exposure or slope. Where spatial effects were not significant between mainland continental locations, fishing effects became evident explaining 6% of the variation in data. No correlation with live coral was detected. Only 37 species, predominantly lower trophic level taxa, were significant in explaining differences in assemblages between sites. Main Conclusions:Spatial and geomorphological histories remain a major influence on the structure of reef fish assemblages in the WIO. Reef geomorphology was closely linked to standing biomass, with "ocean-exposed" fringing reefs supporting high average biomass of ~1,000 kg/ha, while "lagoon-exposed fringing" reefs and "inner seas patch complex" reefs yielded substantially less at ~500kg/ha. Further, the results indicate the influence of benthic communities on fish assemblages is scale dependent. Such insights will be pivotal for managers seeking to balance long-term sustainability of artisanal reef fisheries with conservation of coral reef systems.

Dataset Information

Disentangling the abundance-impact relationship for invasive species.

Publications

Disentangling the abundance-impact relationship for invasive species.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets