Untangling the roles of prey availability, habitat quality and predation as predictors of hedgehog abundance

Lee, K.A., 2021. Untangling the roles of prey availability, habitat quality and predation as predictors of hedgehog abundance. PhD, Nottingham Trent University.

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Abstract

Badgers (Meles meles) are the principal predator of hedgehogs (Erinaceus europeaus) and have been implicated in the decline of hedgehog populations in Britain and elsewhere. Sharing an intra-guild predation relationship, badgers may negatively impact hedgehog populations via predation, creating a 'landscape of fear' leading to avoidance behaviours and / or competition for shared food resources. Previous studies have evaluated the apparent negative relationship between badgers and hedgehogs, suggesting that hedgehogs may be excluded from areas of high badger density. Despite this, the mechanism by which badgers exert a negative pressure on hedgehogs remains unclear. This study aimed to identify the mechanisms that facilitate coexistence amongst badgers and hedgehogs by assessing densities of both species, habitat and food availability, and dietary niche overlap across multiple sites, to establish the importance of potential competition and predation amongst these two species of concern.

Camera trapping and invertebrate sampling were conducted between 2018 and 2019 across twenty-three sites in England and Wales. Of these, two sites were surveyed all year round, to assess seasonal variation in invertebrate prey resources and, through scat analysis, dietary niche assessment for both badgers and hedgehogs. Dietary assessment was performed by analysing scat samples using the DNA metabarcoding technique. Density estimates were calculated for both species using the Random Encounter Model, and occupancy analysis at individual camera locations was used to assess the spatiotemporal relationship.

To date, no studies have compared the diet of badgers and hedgehogs at the same location to determine the extent of dietary competition and the frequency of hedgehog consumption within the diet of rural badgers. Both species exploited many of the same dietary Families, however dietary composition of prey within each scat sample was significantly dissimilar between badger and hedgehog across all seasons, indicating niche partitioning between the two guild members. Hedgehog DNA was identified in only 1.3% of badger samples at sites where hedgehogs were present, suggesting that hedgehogs are not a key prey item for badgers, but are consumed opportunistically. Diet selection indices showed that neither species consume invertebrate prey relative to its abundance and instead exhibit dietary preferences, suggesting that they may compete for the most common shared dietary items.

Furthermore, this study is the first to estimate densities of co-occurring badgers and hedgehogs across multiple sites, showing that hedgehog densities are significantly higher in mixed farmland landscapes, compared with arable-dominated landscapes. Although both species can co-exist at the regional scale, occupancy modelling in this study showed spatial segregation at individual camera trap locations which was driven by species-specific differences in habitat selection. Hedgehogs were found in close proximity to buildings, whereas badgers were found away from buildings, closer to arable habitat. Badger and hedgehog temporal activity showed a high degree of overlap, providing no evidence for temporal separation.

Findings from this novel study have identified dietary and spatial partitioning that are likely important mechanisms facilitating the coexistence of badgers and hedgehogs by reducing competitive and predatory interactions, particularly in mixed farmland habitat. Future studies may look to establish whether habitat selection demonstrated in this study is consistent in different land uses and whether hedgehogs are exhibiting their natural preferences or a landscape of fear response in the presence of badgers.

Item Type: Thesis
Creators: Lee, K.A.
Date: September 2021
Rights: This work is the intellectual property of the author. You may copy up to 5% of this work for private study, or personal, non-commercial research. Any re-use of the information contained within this document should be fully referenced, quoting the author, title, university, degree level and pagination. Queries or requests for any other use, or if a more substantial copy is required, should be directed in the owner(s) of the Intellectual Property Rights.
Divisions: Schools > School of Animal, Rural and Environmental Sciences
Record created by: Linda Sullivan
Date Added: 02 Mar 2022 12:21
Last Modified: 02 Mar 2022 12:21
URI: http://irep.ntu.ac.uk/id/eprint/45783

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