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Abstract Habitat loss disrupts species interactions through local extinctions, potentially orphaning species that depend on interacting partners, via mutualisms or commensalisms, and increasing secondary extinction risk. Orphaned species may become functionally or secondarily extinct, increasing the severity of the current biodiversity crisis. While habitat destruction is a major cause of biodiversity loss, the number of secondary extinctions is largely unknown. We investigate the relationship between habitat loss, orphaned species, and bipartite network properties. Using a real seed dispersal network, we simulate habitat loss to estimate the rate at which species are orphaned. To be able to draw general conclusions, we also simulate habitat loss in synthetic networks to quantify how changes in network properties affect orphan rates across broader parameter space. Both real and synthetic network simulations show that even small amounts of habitat loss can cause up to 10% of species to be orphaned. More area loss, less connected networks, and a greater disparity in the species richness of the network's trophic levels generally result in more orphaned species. As habitat is lost to land‐use conversion and climate change, more orphaned species increase the loss of community‐level and ecosystem functions. However, the potential severity of repercussions ranges from minimal (no species orphaned) to catastrophic (up to 60% of species within a network orphaned). Severity of repercussions also depends on how much the interaction richness and intactness of the community affects the degree of redundancy within networks. Orphaned species could add substantially to the loss of ecosystem function and secondary extinction worldwide.
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Land use changes result in increased phylogenetic clustering and preferential loss of species-rich sites for Michigan floral assemblages.
Abstract Distribution models are widely used to understand landscape biodiversity patterns, facilitate evolutionary and ecological studies, and for making informed conservation decisions. While it is common to examine consequences of climate change, impacts of land use on distributions, a major factor in limiting ranges and corridors between populations, are less well understood. Here, we use distribution models to quantify changes in biodiversity due to land use for Michigan floral assemblages. We leveraged a distribution model dataset (1930 species) integrated with dated phylogenetic information and USGS land use maps to parse Michigan areas with unsuitable habitat. Additionally, we quantify the degree of high-quality habitat lost for each species, identifying those most strongly impacted by land use changes. Approx. 39% of Michigan terrestrial habitat fell within “unsuitable” land use categories. Sites predicted to harbor the most species based on climatic variables were those sites that lost the greatest proportion due to land use changes. Further, excluded sites were preferentially those composed of more phylogenetically even communities. Overall, the impact of land use changes on community species richness was the preferential loss of sites with the predicted highest biodiversity. For phylodiversity metrics, land use changes increased the degree of community phylogenetic clustering. This results in overall decreased phylodiversity, leading to assemblages less equipped to respond to rapid climatic changes. Our results confirm land use to be a major, but somewhat overlooked, factor impacting local diversity dynamics and illustrate how local-scale land use impacts regional-scale richness and phylodiversity patterns, likely leading to increased community fragility.
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- Award ID(s):
- 1930007
- PAR ID:
- 10635470
- Publisher / Repository:
- Research Square
- Date Published:
- Format(s):
- Medium: X
- Institution:
- Research Square
- Sponsoring Org:
- National Science Foundation
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Habitat alteration and destruction are a primary driver of biodiversity loss. There is a plethora of research documenting similarly strong patterns of decline across ecosystem types and spatial scales. However, evolutionary dimensions remain largely unexplored in many systems. For example, little is known about how habitat alteration/loss can lead to phylogenetic deconstruction of ecological assemblages at the local level. That is, while species loss is evident, are some lineages favored over others? Using a long-term dataset of a globally, ecologically important guild of invertebrate consumers, stream leaf “shredders,” we created a phylogenetic tree of the taxa in the regional species pool, calculated mean phylogenetic distinctiveness for > 1000 communities spanning > 10 y period, and related species richness, phylogenetic diversity and distinctiveness to watershed-scale impervious cover. Using a combination of changepoint and compositional analyses, we learned that increasing impervious cover produced marked reductions in all three measures of diversity, and in particular, aid in understanding both phylogenetic diversity and average assemblage phylogenetic distinctiveness. Our findings suggest that, not only are species lost when there is an increase in watershed urbanization, as other studies have demonstrated, but that those lost are members of more distinct lineages relative to the community as a whole.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Posted Content:
- https://doi.org/10.21203/rs.3.rs-2967584/v1
