Predation patterns across states of landscape fragmentation can shift with seasonal transitions.

Journal Article (Journal Article)

Nested scales of habitat heterogeneity may independently or synergistically influence faunal interactions. Fragmentation effects (i.e., the breaking apart of landscapes) and edge effects (i.e., ecological differences between edges and interiors of patches, nested within landscapes) are distinct yet related ecological concepts, linked mathematically by the habitat edge-to-area ratio. Our study quantified the separate and interactive effects of fragmentation and edge on predation using temperate seagrass. To assess how predation and generalized consumption were influenced by fragmentation state (i.e., continuous, fragmented), and proximity to edge (i.e., edges, interiors), we used tethering assays with two prey-items: juvenile crabs, Callinectes sapidus, and "squidpops" (dried squid mantle). We also investigated whether faunal densities (a proxy for consumption potential) and temperature (a proxy for a broad suite of seasonal changes) correlated with predation across landscapes. Results showed fragmentation state affected predation (i.e., crab) mortality, yet edge effects did not. Moreover, the directionality of fragmentation effects shifted across a temperature/seasonal gradient. Predation mortality more than doubled in continuous landscapes amidst temperature increases, surpassing initially higher mortality in fragmented landscapes, which did not systematically vary with temperature. This mortality magnitude "flip" matched spatiotemporal trends in faunal densities between continuous and fragmented meadows. Consumption rates of both prey-items increased alongside temperature and neither demonstrated edge effects. However, crabs showed fragmentation effects not seen with squidpops, suggesting differing foraging strategies used by consumers of these prey-items. We conclude that fragmentation and edge effects have dynamic influences on temperate predator-prey interactions, as faunal favorability of habitat heterogeneity can "flip" temporally.

Full Text

Duke Authors

Cited Authors

  • Yarnall, AH; Fodrie, FJ

Published Date

  • June 2020

Published In

Volume / Issue

  • 193 / 2

Start / End Page

  • 403 - 413

PubMed ID

  • 32556593

Electronic International Standard Serial Number (EISSN)

  • 1432-1939

International Standard Serial Number (ISSN)

  • 0029-8549

Digital Object Identifier (DOI)

  • 10.1007/s00442-020-04675-z

Language

  • eng