Different responses of predator and prey functional diversity to fragmentation

Abstract

The study of functional diversity, or the range of species' ecological roles in a community, is a rapidly expanding area in ecology. Given the extent that ecosystems are being altered, effort should shift toward assessing variation in functional diversity across landscapes with the goal of improving land use management decisions. We construct a workflow that creates three-dimensional surfaces and maps of functional diversity to examine changes in beetle functional diversity across an Indiana, USA landscape. We sampled 105 prey wood-borer and predator beetle species along a gradient of forest fragmentation across Indiana and used a number of functional traits from literature sources to capture their functional roles. We developed newly measured functional traits to estimate several traits relevant to beetles' ecological function that was unknown and not easily measured. Functional diversity indices (FRic, FDis, FDiv, and FEve) were calculated from species abundance and functional traits and used to assess changes in functional diversity along the fragmentation gradient. We predicted that habitat fragmentation would have a greater negative impact on predator beetle functional diversity than prey wood-borer functional diversity. Landscape metrics most important to the functional diversity of both wood-borer and predator beetle communities were landscape division index (LDI, an assessment of landscape subdivision) and mean shape index (MSI, a measure of patch shape complexity). Overall, three-dimensional surfaces of functional diversity and functional diversity maps across the Indiana landscape revealed that beetle functional diversity was greatest with minimal landscape subdivision. Opposite to what we predicted, we found that the prey wood-borer functional diversity was more negatively impacted by LDI than the predator beetle functional diversity. Furthermore, predator beetle functional diversity was greater with increasing MSI. The map predicted predator FRic to be highest in forested areas with intact habitat and also less sensitive to habitat fragmentation adjacent to more continuous forest. We propose that land management may be guided by revealing landscapes that are most appropriate for maximizing functional diversity of multiple communities or shifting the relative abundance within prey and beneficial predator beetle functional groups with the use of three-dimensional plots or maps.

A global class reunion with multiple groups feasting on the declining insect smorgasbord

“…3d). To go deeper into ecological questions, it would be advisable to add analysis of functional diversity of prey, such as prey diversity indices, to receive a better understanding of how the ecosystem works [57][58][59] . By achieving this, we will reach a novel insight into the ecology of insectivores, how predators are linked through shared prey, and to which extent the declining populations of both might alter these interactions.…”

Contrasting effects of urbanization on arboreal and ground-dwelling land snails: role of trophic interactions and habitat fragmentation

“…Anthropogenic disturbances create drier and warmer environments (Gallo and Owen 1999;Kalnay and Cai 2003;Yang et al 2017), and species sensitive to those changes (e.g., lichens and mosses) are known to develop markedly different communities in urban versus non-urban areas (Lättman et al 2014;Oishi 2018). Recent studies have demonstrated that land-use changes have a large influence on functional diversity, which is closely related to ecosystem services (Kissick et al 2018).…”

“…Although there has been increased interest in biodiversity-urbanization relationships in recent years, the available literature is biased towards vertebrate studies, especially birds (Ritchie and Johnson 2009;Gagné and Fahrig 2011). Yet invertebrates represent a majority of animal diversity (Groombridge and Jenkins 2002) and have distinctive ecological functions (Mason 1970;Kissick et al 2018). Moreover, molluscs are important conservation targets because of their high diversity, large number of extinction records (Lydeard et al 2004), and ability to be used as ecosystem indicators due to their limited dispersal ability (Hodges and McKinney 2018).…”

Novel management tools for subsidized avian predators and a case study in the conservation of a threatened species

“…Recent evidence suggests that changes to available resources arising from fragmented habitats negatively impact prey species more than predator species (Kissick et al. ). Herein, we investigate restorative management strategies and custom tools that may be used to curtail or reverse undesirable shifts experienced by wildlife populations in anthropogenically altered habitats.…”

“…Human subsidies may change habitat conditions such that once rare resources, such as food, water, and nesting opportunities, are increasingly available for nuisance wildlife use. Recent evidence suggests that changes to available resources arising from fragmented habitats negatively impact prey species more than predator species (Kissick et al 2018). Herein, we investigate restorative management strategies and custom tools that may be used to curtail or reverse undesirable shifts experienced by wildlife populations in anthropogenically altered habitats.…”