Human disturbance has contrasting effects on niche partitioning within carnivore communities

Abstract

Among species, coexistence is driven partly by the partitioning of available resources. The mechanisms of coexistence and competition among species have been a central topic within community ecology, with particular focus on mammalian carnivore community research. However, despite growing concern regarding the impact of humans on the behaviour of species, very little is known about the effect of humans on species interactions. The aim of this review is to establish a comprehensive framework for the impacts of human disturbance on three dimensions (spatial, temporal and trophic) of niche partitioning within carnivore communities and subsequent effects on both intraguild competition and community structure. We conducted a systematic review of the literature on carnivore niche partitioning (246 studies) and extracted 46 reported effects of human disturbance. We found evidence that human disturbance impacts resource partitioning, either positively or negatively, in all three niche dimensions. The repercussions of such variations are highly heterogeneous and differ according to both the type of human disturbance and how the landscape and/or availability of resources are affected. We propose a theoretical framework of the three main outcomes for the impacts of human disturbance on intraguild competition and carnivore community structure: (i) human disturbance impedes niche partitioning, increasing intraguild competition and reducing the richness and diversity of the community; (ii) human disturbance unbalances niche partitioning and intraguild competition, affecting community stability; and (iii) human disturbance facilitates niche partitioning, decreasing intraguild competition and enriching the community. We call for better integration of the impact of humans on carnivore communities in future research on interspecific competition.

Prey availability and intraguild competition regulate the spatiotemporal dynamics of a modified large carnivore guild

“…Spatiotemporal dynamics play an important role in facilitating coexistence between the large carnivore guild, yet little is known about these dynamics in human-altered landscapes (Sévêque et al, 2020).…”

Disturbance type and species life history predict mammal responses to humans

“…Disturbance effects on animal distribution and activity are typically assumed to be negative (Belote et al, 2020; Dirzo et al, 2014), yet for some species, human activities confer benefits as well as costs. These trade‐offs are particularly common for mammals, as greater resource availability and reduced competition or predation in human‐dominated landscapes (Bateman & Fleming, 2012; Moll et al, 2018) may offset the impacts of habitat loss and exposure to anthropogenic mortality (Hill et al, 2020; Sévêque et al, 2020). At the community level, the differential responses of species to human disturbance may have a filtering effect (Aronson et al, 2016; Santini et al, 2019), such that only species with “winning” combinations of ecological and life history traits (i.e., those suited to coexistence with humans) will persist in disturbed environments (Pineda‐Munoz et al, 2021).…”

“…However, variation among populations may obscure the link between species‐level traits and measured responses to human disturbance. Within a given mammal species, populations frequently vary in the intensity or directionality of their response to a given disturbance type depending on local conditions, including habitat productivity and exposure to anthropogenic mortality (Belote et al, 2020; Kays et al, 2017; Moreno‐Rueda & Pizarro, 2009; Sévêque et al, 2020). Indeed, studies of recreation impacts in protected areas commonly report contrasting responses to human presence by different populations of the same species (Bateman & Fleming, 2017; Patten & Burger, 2018; Reed & Merenlender, 2008; Reilly et al, 2017), and use of developed areas may also vary among populations based on trade‐offs between anthropogenic threat and resource availability (Bateman & Fleming, 2012; Carlos et al, 2009).…”

Niche partitioning between sympatric wild canids: the case of the golden jackal (Canis aureus) and the red fox (Vulpes vulpes) in north-eastern Italy

“…Sympatric species with similar ecological requirements can either coexist or competitively exclude each other depending on resources availability: the strength of the competition between them generally decreases with increased differentiated resources use ([ 1 ] and references therein). Considering carnivores, exploitation [ 2 ] and interference [ 3 ] have been identified as key mechanisms structuring the guild; the magnitude of interspecific aggressive behaviours is generally driven by relative differences in body sizes (i.e.…”