Complex organism–environment feedbacks buffer species diversity against habitat fragmentation

Abstract

Understanding the factors that determine the extent of biodiversity loss following habitat destruction is central to ecosystem conservation and management. One potential factor is the ecological feedbacks between organisms and local environmental conditions, which can influence how species affect one another and, consequently, whether or not species persist in fragmented landscapes. We investigated this possibility using a spatially explicit individual‐based model of plant communities. In this model, plant species affected their own and other species’ competitiveness by modifying local environmental conditions. These plant–environment feedbacks were assumed to vary among species pairs in direction and strength to mimic complex feedbacks observed between plants and soil conditions in real communities. We found that complex feedbacks reduced the extent of diversity loss, effectively buffering species against habitat fragmentation. Our analysis suggested that this buffering effect operated via two mechanisms. First, complex feedbacks decreased the likelihood of immediate extinction by making the spatial distribution of each species less clustered and consequently less likely to be eliminated entirely by fragmentation. Second, complex feedbacks decreased the likelihood of additional extinction by generating negative density dependence among surviving species, thereby keeping low‐abundance species from going extinct due to demographic stochasticity and other forces. The buffering effect was particularly strong when species dispersed locally and abiotic environmental conditions varied globally. Our findings highlight the potential importance of organism–environment feedbacks in explaining species extinction by habitat destruction.

Host‐specific effects of soil microbial filtrates prevail over those of arbuscular mycorrhizae in a fragmented landscape

“…Plant-soil feedbacks have been widely studied (Van der Putten et al 2013); however, their role in the context of habitat fragmentation and ecosystem degradation is still poorly understood (Zee and Fukami 2014). In a previous study (Pizano et al 2014), we showed that plant growth and survival was differentially impacted both in the greenhouse and the field by whole-soil microbial communities from habitats representing a disturbance gradient in a highly fragmented landscape.…”

“…Thus, feedbacks mediated by soil organisms such as bacteria and non-AMF fungi in addition to AMF, may be crucial for decreasing the likelihood of species extinctions in fragmented landscapes by reducing the spatial clustering of individuals across the landscape (Zee and Fukami 2014), although further studies are required for exploring the diversity and ecological function of these organisms. Pastures accumulate AMF and non-AMF organisms that are detrimental to the grass B. brizantha, but benefit coffee and pioneer forest species, while forest fragments hold non-AMF, beneficial microbes that improved the growth of coffee.…”

“…In particular, the interaction between plants and soil organisms in their local environment may be important in determining whether species persist or go extinct after habitat loss and fragmentation (Zee and Fukami 2014). In particular, the interaction between plants and soil organisms in their local environment may be important in determining whether species persist or go extinct after habitat loss and fragmentation (Zee and Fukami 2014).…”

The diversity of diversity studies: retrospectives and future directions

“…The first major theme, diversity and assembly, was examined in all six contributions (Kissling and Schleuning , Melian et al , Michalet et al , Sandel , Schleuning et al , Zee and Fukami ). The primary conclusions associated with this theme included the following (but see Table for complete listings).…”

“…Ecological networks – both trophic and non‐trophic – have been previously proposed as important to community assembly (Bascompte et al , Memmott et al , Verdú and Valiente‐Banuet , Kéfi et al ). In this special issue, three studies directly examined and discussed the importance of networks (Kissling and Schleuning , Melian et al , Schleuning et al ), whilst two others indirectly examined networks by exploring basal facilitation and interactions but did not explicitly invoke the term to describe their respective networks (Michalet et al , Zee and Fukami ). Consequently, the use of network tools to study biodiversity on environmental gradients and across scales is likely to continue to become an important future direction.…”