Increases in local richness (α-diversity) following invasion are offset by biotic homogenization in a biodiversity hotspot

Kortz, Alessandra Rocha; Magurran, Anne E.

doi:10.1098/rsbl.2019.0133

Cited by 39 publications

(31 citation statements)

References 34 publications

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“…In fragmented landscapes, local extinctions often result from species that are unable to persist under newly disturbed habitat conditions [16,17]. However, species composition is additionally susceptible to changes due to the proliferation of common, introduced, habitat generalist and/or open-habitat species [17][18][19], which can offset extinctions in disturbed habitats [20,21]. Across the Amazonian deforestation arc, the creation of anthropogenic habitats provides novel opportunities for the expansion of open-habitat species (i.e., those whose geographic distributions are centered in open-habitat biomes) from neighbouring savannah-like biomes.…”

Section: Introductionmentioning

confidence: 99%

Marked decline in forest-dependent small mammals following habitat loss and fragmentation in an Amazonian deforestation frontier

2020

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Agricultural frontier expansion into the Amazon over the last four decades has created million hectares of fragmented forests. While many species undergo local extinctions within remaining forest patches, this may be compensated by native species from neighbouring open-habitat areas potentially invading these patches, particularly as forest habitats become increasingly degraded. Here, we examine the effects of habitat loss, fragmentation and degradation on small mammal assemblages in a southern Amazonian deforestation frontier, while accounting for species-specific degree of forest-dependency. We surveyed small mammals at three continuous forest sites and 19 forest patches of different sizes and degrees of isolation. We further sampled matrix habitats adjacent to forest patches, which allowed us to classify each species according to forest-dependency and generate a community-averaged forest-dependency index for each site. Based on 21,568 trap-nights, we recorded 970 small mammals representing 20 species: 12 forest-dependents, 5 matrix-tolerants and 3 open-habitat specialists. Across the gradient of forest patch size, small mammal assemblages failed to show the typical species-area relationship, but this relationship held true when either species abundance or composition was considered. Species composition was further mediated by community-averaged forest-dependency, so that smaller forest patches were occupied by a lower proportion of forest-dependent rodents and marsupials. Both species richness and abundance increased in less isolated fragments surrounded by structurally simplified matrix habitats (e.g. active or abandoned cattle pastures). While shorter distances between forest patches may favour small mammal abundances, forest area and matrix complexity dictated which species could persist within forest fragments according to their degree of forest-dependency. Small mammal local extinctions in small forest patches within Amazonian deforestation frontiers are therefore likely offset by the incursion of open-habitat species. To preclude the dominance of those species, and consequent losses of native species and associated ecosystem functions, management actions should

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Section: Introductionmentioning

confidence: 99%

Marked decline in forest-dependent small mammals following habitat loss and fragmentation in an Amazonian deforestation frontier

2020

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“…These findings contrast with current global projections of aboveground biodiversity declines, but they do not necessarily provide a more positive view of the future of nature. Although increases in local microbial diversity might seem positive, these hide strong reductions in community complexity (Kortz & Magurran, 2019) in the majority of terrestrial systems, with implications for ecosystem functioning. This belowground trend is now mostly missing from policy documents and nature conservation assessments, which diminishes the capacity of policy‐makers to make informed decisions about the future of soil ecosystems.…”

Section: Discussionmentioning

confidence: 99%

Global projections of the soil microbiome in the Anthropocene

Guerra

Delgado‐Baquerizo

Duarte

et al. 2021

Global Ecol. Biogeogr.

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Aim Soil microbes are essential for maintenance of life‐supporting ecosystem services, but projections of how these microbes will be affected by global change scenarios are lacking. Therefore, our aim was to provide projections of future soil microbial distribution using several scenarios of global change. Location Global. Time period 1950–2090. Major taxa studied Bacteria and fungi. Methods We used a global database of soil microbial communities across six continents to estimate past and future trends of the soil microbiome. To do so, we used structural equation models to include the direct and indirect effects of changes in climate and land use in our predictions, using current climate (temperature and precipitation) and land‐use projections between 1950 and 2090. Results Local bacterial richness will increase in all scenarios of change in climate and land use considered, although this increase will be followed by a generalized community homogenization process affecting > 85% of terrestrial ecosystems. Changes in the relative abundance of functional genes associated with the increases in bacterial richness are also expected. Based on an ecological cluster analysis, our results suggest that phylotypes such as Geodermatophilus spp. (typical desert bacteria), Mycobacterium sp. (which are known to include important human pathogens), Streptomyces mirabilis (major producers of antibiotic resistance genes) or potential fungal soil‐borne plant pathogens belonging to Ascomycota fungi (Venturia spp., Devriesia spp.) will become more abundant in their communities. Main conclusions Our results provide evidence that climate change has a stronger influence on soil microbial communities than change in land use (often including deforestation and agricultural expansion), although most of the effects of climate are indirect, through other environmental variables (e.g., changes in soil pH). The same was found for microbial functions such as the prevalence of phosphate transport genes. We provide reliable predictions about the changes in the global distribution of microbial communities, showing an increase in alpha diversity and a homogenization of soil microbial communities in the Anthropocene.

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“…NNS introduced by humans are considered undesirable in PAs, the purpose of which is to preserve nature in as pristine a state as possible (Hettinger, 2001). The presence of NNS also potentially contributes to increasing homogenization of native biological communities (McKinney and Lockwood, 1999;Lambdon et al, 2008;Kortz and Magurran, 2019).…”

Section: Introductionmentioning

confidence: 99%

Non-native Species Surrounding Protected Areas Influence the Community of Non-native Species Within Them

et al. 2021

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Protected areas (PAs) are a key element of global conservation strategies aiming to protect habitats and species from various threats such as non-natives species (NNS) with negative ecological impacts. Yet little is known about the mechanisms by which PAs are colonized by NNS, and more specifically the role of colonizing events from surrounding areas. Here, we compared terrestrial and freshwater non-native plants and animals recorded in Norwegian PAs and in 5-km belts around them, using the database of the Norwegian Biodiversity Information Centre Species Map Service. Our analysis included 1,602 NNS and 671 PAs. We found that NNS were recorded in only 23% of the PAs, despite the fact that 90% of the 5-km belts were colonized by at least one NNS. A Zero-inflated negative binomial regression model showed that the number of NNS in the 5-km belts was a strong explanatory variable of the NNS richness inside PAs. Other significant variables included the surface area of the PA, mean human population density in the PA, main type of habitat and accessibility of PAs. We also observed similarity in the species in and around the PAs, with, on average, two thirds of the NNS present in a specific PA also present in its 5-km belt. Furthermore, NNS were recorded in PAs on average 4.5 years after being recorded in the 0–5 km belts, suggesting a dynamic of rapid colonization from the belts to the PAs. Invasive NNS represented 12% of NNS in the belts but 40% in the PAs. This difference was related to the higher abundance of invasive NNS in the belts. Our results highlight the necessity of expanding the focus of NNS management in PAs beyond their boundaries, in particular to prevent incursions of NNS with high negative ecological impact.

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Increases in local richness (α-diversity) following invasion are offset by biotic homogenization in a biodiversity hotspot

Cited by 39 publications

References 34 publications

Marked decline in forest-dependent small mammals following habitat loss and fragmentation in an Amazonian deforestation frontier

Marked decline in forest-dependent small mammals following habitat loss and fragmentation in an Amazonian deforestation frontier

Global projections of the soil microbiome in the Anthropocene

Non-native Species Surrounding Protected Areas Influence the Community of Non-native Species Within Them

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