Upscaling the niche variation hypothesis from the intra- to the inter-specific level

Abstract

The "niche variation hypothesis" (NVH) predicts that populations with wider niches should display higher among-individual variability. This prediction originally stated at the intra-specific level may be extended to the inter-specific level: individuals of generalist species may differ to a greater extent than individuals of a specialist species. We tested the NVH at intra- and inter-specific levels based on a large diet database of three large herbivore feces collected in the field and analyzed using DNA metabarcoding. The three herbivores (roe deer Capreolus capreolus, chamois Rupicapra rupicapra and mouflon Ovis musimon) are highly contrasted in terms of sociality (solitary to highly gregarious) and diet. The NVH at the intraspecific level was tested by relating, for the same population, diet breadth and inter-individual variation across the four seasons. Compared to null models, our data supported the NVH both at the intra- and inter-specific levels. Inter-individual variation of the diet of solitary species was not larger than in social species, although social individuals feed together and could therefore have more similar diets. Hence, the NVH better explained diet breadth than other factors such as sociality. The expansion of the population niche of the three species was driven by resource availability, and achieved by an increase in inter-individual variation, and the level of inter-individual variability was larger in the generalist species (mouflon) than in the specialist one (roe deer). This mechanism at the base of the NVH appears at play at different levels of biological organization, from populations to communities.

Reproductive class influences risk tolerance during denning and spring for American black bears (Ursus americanus)

“…Individual variability can decrease inter‐individual competition and should be facilitated by traits such as large body size or a generalist diet (Bison et al. ). Moreover, individual variability should be positively associated with the heterogeneity of areas exploited by different individuals, which will thrive in diverse areas and allow for successfully coping with unpredictable situations at the population level (Møller and Garamszegi ).…”

Is resource partitioning the key? The role of intra‐interspecific variation in coexistence among five small endemic fish species (Characidae) in subtropical rivers

“…Dietary preferences can also influence the use of resources (Novakowski et al ., ; Tófoli et al ., ; Walker et al ., ), such that intraspecific variations are considered key factors in the understanding of the mechanisms that promote coexistence (Bison et al ., ; Bolnick et al ., ; Chase & Leibold, ; Zaret & Rand, ). All species studied showed high intraspecific variability.…”

Combining point‐process and landscape vegetation models to predict large herbivore distributions in space and time—A case study of Rupicapra rupicapra

“…We collected 659 fresh faeces of chamois within the NGWR from April to November 2007 and 2008, either in the field or directly from trapped and hunted chamois. The dietary composition of the faeces was determined using DNA metabarcoding techniques (Bison et al., ; Rayé et al., ). We identified 326 plant taxa in the faeces sampled.…”

“…We identified 326 plant taxa in the faeces sampled. We removed plant species which were present at levels under 2.5% of DNA sequences in the faeces, considering that under this threshold, the taxa detected represent a marginal resource for the chamois or may result from barcoding errors (Bison et al., ). This 2.5% threshold was taken as it marked a rupture in the frequency distribution of the sequences (Pompanon et al., ).…”

“…In this paper, we implemented a novel framework in which the distribution of the emblematic mountain herbivore of the European Alps, Rupicapra rupicapra (chamois), is modelled in a regional park in France, using climatic, resource and land cover variables, by integrating multiple sources of information and combining point‐process model with spatially explicit vegetation simulations. In order to do this, we first used a unique database on the compositional diet of the chamois obtained for the study site by sequencing the environmental DNA found in multiple faeces of the species (Bison et al., ). Secondly, we built sixteen plant functional groups (PFGs) that account for the chamois’ diet, as well as climatic requirements, dispersal limitations, successional stage, competitive ability and competitive tolerance (Boulangeat et al., ).…”