Habitat partitioning and spatial segregation at multiple scales promotes year-round coexistence in a guild of forest songbirds

Abstract

AbstractDespite ecological, biological, or genetic similarities, species belonging to the same guild should exhibit some degree of niche differentiation to coexist in the same area. Understanding the mechanisms promoting coexistence among ecologically similar and phylogenetically related species is crucial to improve our understanding of how biodiversity is maintained across broad temporal scales.We examined the mechanisms driving coexistence in a guild of 5 sympatric woodland songbirds (family Paridae) in mixed forests of south-central Europe. We performed interspecific comparisons of habitat and space use considering two different phenological periods (breeding and non-breeding) and two spatial scales (home-range and foraging habitat), as well as spatial segregation of breeding territories.Based on broad-scale habitat preferences, two distinct and seasonally consistent species subgroups were identified within the guild, namely broadleaf and conifer species. During breeding, we showed that all species largely overlapped in their use of different foraging micro-habitats within the tree canopy, even within each subgroup. Yet, we detected significant spatial segregation of breeding territories among species. On the contrary, during the non-breeding period, individuals of different species within mixed flocks foraged on different and complementary sectors of the canopy, thus partitioning foraging habitats.This study highlights that coexistence within the south-central European tit guild across different phenological periods is facilitated by a combination of distinct and complementary mechanisms, including spatial segregation of breeding territories, revealing how sympatric closely-related species coexist through both broad- and fine-scale spatial niche differentiation.