Sett Use, Density and Breeding Phenology of Badgers in Mediterranean Agro-Sylvo-Pastoral Systems.

Marcelo Silva,Luís Miguel Rosalino,Sandra Alcobia,Margarida Santos-Reis

doi:10.3390/ani11092663

Marcelo Silva, Luís Miguel Rosalino + Show 2 more

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https://doi.org/10.3390/ani11092663

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Abstract

Simple SummaryUnderstanding carnivores social structure variation is pivotal for properly addressing conservation challenges and solutions. The European badgers is a social carnivore for which most of the available information regarding how this species is socially organized derives from central west populations. This article describes the group composition, den use patterns and breeding phenology of a Mediterranean population of badgers. We showed that badger live in low density, in relatively small groups, composed by 2–4 adult animals and ca. 2 cubs, born in winter. These patterns, representing a variation of what was described for other populations, show that badgers take advantage of the landscape context, where human-related resources and mild environmental conditions allow badger to reach higher densities than in many southern populations, and to reproduce earlier than their northern counterparts.Carnivores social organization varies widely, from strongly social to solitary predators. European badgers are facultative social carnivores that also shows a geographical variation in social structure. These patterns derive mainly from central/west European regions, with an under-representation of Mediterranean populations that face different conservation challenges, especially regarding group composition, sett use patterns and breeding phenology. We addressed these traits topics for a population inhabiting a Portuguese agro-silvo-pastoral system. Based on monthly monitoring of 34 setts and continuous camera-trapping surveys of 12, we showed that setts surrounded by diversified vegetation and located in sandy sites are more used, a pattern probably linked to food availability and ease of sett excavation and maintenance, respectively. Badgers followed a general pattern regarding group size (2–4 adults), but showed an intermediate population density (0.49–0.73 badgers/km2), with values higher than those estimated for other Mediterranean environments, but lower than for central-western populations. This, together with the breeding (November/January) and cub emergence (1.8 cubs/sett; March/April) periods, indicates an ecological adaptation to the landscape context, where human-related resources and mild environmental conditions allow badger to reach higher densities than in many southern populations, and to reproduce earlier than their northern counterparts.

Highlights

Twenty-three new setts were added as a result of the field work, totalizing 45 setts for monitoring purposes (Figure 1B), resulting in a sett density of 1.05 setts/km2
The European badger shows a high adaptability throughout its wide distribution range highlighted by its wide variation in feeding habits [50], density [7], group size [7], or habitat use patterns and drivers [8]
The monitored badger population showed a variation in the frequency of sett use, and this heterogeneity in how they utilize the available dens seems to be driven by three different, but complementary drivers, that highlight the importance of regional characteristics: vegetation structure, soil composition and disturbance

Summary

Introduction

Carnivores show a wide array of social organizations, ranging from solitary (e.g., wildcats, Felis silvestris) to highly social species, such as the meerkat (Suricata suricatta) [1]. While wolves (Canis lupus) can form packs with more than 40 animals sharing hunting, territory patrolling and defense, cub rearing, and other activities [3], others, such as European badgers (Meles meles), form clans usually with less than seven individuals that share the same refuge and territory and show some intra-clan interactions, but lack the social sophistication showed by highly social species [4]. The way badger social groups are organized and use the communal refuges they build (known as setts) is highly variable across its distribution range and this variability still poses questions about how the landscape context may shape this species’ social patterns

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