Landscape configuration affects probability of apex predator presence and community structure in experimental metacommunities

Abstract

Biodiversity is declining at an unprecedented rate, highlighting the urgent requirement for well-designed protected areas. Design tactics previously proposed to promote biodiversity include enhancing the number, connectivity, and heterogeneity of reserve patches. However, how the importance of these features changes depending on what the conservation objective is remains poorly understood. Here we use experimental landscapes containing ciliate protozoa to investigate how the number and heterogeneity in size of habitat patches, rates of dispersal between neighbouring patches, and mortality risk of dispersal across the non-habitat ‘matrix’ interact to affect a number of diversity measures. We show that increasing the number of patches significantly increases γ diversity and reduces the overall number of extinctions, whilst landscapes with heterogeneous patch sizes have significantly higher γ diversity than those with homogeneous patch sizes. Furthermore, the responses of predators depended on their feeding specialism, with generalist predator presence being highest in a single large patch, whilst specialist predator presence was highest in several-small patches with matrix dispersal. Our evidence emphasises the importance of considering multiple diversity measures to disentangle community responses to patch configuration.

Corridor quality buffers extinction under extreme droughts in experimental metapopulations

“…Experimental microcosms provide one alternative method to achieve this, as they allow landscape‐style manipulations at an observable scale (Altermatt et al, 2015; Benton et al, 2007). Indeed, such systems have previously been used to study the effect of network modularity (e.g., Gilarranz et al, 2017), and the impact of habitat configuration on metacommunities (e.g., Chisholm et al, 2011; Wolfe et al, 2022).…”

Spatiotemporal thermal variation drives diversity trends in experimental landscapes

“…Simplified experimental approaches such as microcosms and mesocosms are a valuable tool in this sense (Arnott et al, 2021 ) because they permit the creation of artificial ecosystems with customised landscape structures (Wolfe, Hammill, et al, 2022 ), manipulation of communities according to species traits, abundance and assembly order (Clements et al, 2013 ), and precise modification of temperature (Jiang & Morin, 2007 ). These approaches have been invaluable in their ability to describe the effects of temperature on fine‐scale processes such as coexistence of competing species (Jiang & Morin, 2007 ), predator–prey dynamics (Salt et al, 2017 ) and changes in body size (Laakso et al, 2003 ).…”