Competitor densities, habitat, and weather: effects on interspecific interactions between wild deer species

Abstract

There is a growing interest on the potential interplay between weather, habitat, and interspecific competition on population dynamics of wild herbivores. Favorable environmental conditions may buffer the negative effects of competition; conversely, competition may be expected to be stronger under harsh environmental conditions. We investigated relationships between competitor abundance, weather, and habitat cover on density and local distribution of a medium‐sized herbivore, the roe deer Capreolus capreolus, as well as its spatial overlap with fallow deer Dama dama in a Mediterranean protected area. Over 11 years (2007–2017), roe deer density was not affected by spring–summer rainfall in the previous year and decreased with increasing density of fallow deer in the previous year. Hence, over the considered temporal scale, results supported a major role of competition over weather in influencing population trends of roe deer. At a finer spatial scale, roe deer occupancy was negatively affected by local abundance of fallow deer, especially in “poorer” habitats. We found a slight support for a positive effect of fallow deer density on interspecific spatial overlap. Moreover, fine‐scale spatial overlap between deer species increased with decreasing rainfall in spring–summer. Fallow deer were introduced to our study area in historical times and their role as superior competitors over roe deer has been found also in other study areas. We suggest a potential role of harsh weather conditions during the growing season of vegetation (i.e. scarce rainfall) in triggering the potential for ecological overlap, emphasizing the negative effects of interspecific competition.

Spatiotemporal patterns of wolf, mesocarnivores and prey in a Mediterranean area

“…Bonnot et al 2013;Sönnichsen et al 2013;Lone et al 2014). In our study area, behaviour, distribution and density of this ungulate have been shown to be negatively influenced by interspecific competition with the fallow deer (Ferretti et al 2011;Ferretti and Fattorini 2020). Thus, roe deer avoidance of sites with high local density of fallow deer may limit the risk of encounters with wolves (Ferretti et al 2019).…”

Invasive water buffalo population trends and competition-related consequences for native rusa deer in eastern Indonesian protected areas

“…First, we examined temporal and spatial variation in feral water buffalo dung abundance. Human actions alongside rainfall, population density, water resources and forage availability are important processes that influence temporal or spatial variation in ungulate population abundances (Clutton-Brock et al 1997;Coulson et al 2000;Ferretti and Fattorini 2020;Imperio et al 2012). Similarly, we predicted that one or more of these processes could explain annual variation in water buffalo dung abundance.…”

“…However, we found a strong negative correlation between water buffalo and rusa deer population dung abundance. A decreased local abundance in one or both interacting species is often required to suggest the effects of interspecific competition (Chesson 2000;Ferretti and Fattorini 2020;Putman 1996). Two forms of competition can result in the direct and indirect resource exclusion between interacting herbivore species (Forsyth and Hickling 1998;Jung et al 2015;Ritchie et al 2009;Sinclair 1985;Valeix et al Fig.…”

“…Indeed the resource use shift documented in rusa deer could be a key strategy to reduce competition with water buffalo (Chesson 2000;Shea and Chesson 2002). So, although they exist at lower densities when water buffalo are common, rusa deer may also increase their use of open deciduous forest to reduce the effects of competition and buffer population growth rates to avoid the potential for local extinction (Ferretti and Fattorini 2020).…”

Importance of species traits on individual-based seed dispersal networks and dispersal distance for endangered trees in a fragmented forest

“…In most remnant habitat patches, mutualistic networks for animal-mediated pollination and seed dispersal are disrupted by species loss ( Schupp et al., 2017 ; Grass et al., 2018 ) and affected by the size and quality of habitat patches ( Spiesman and Inouye, 2013 ; de Bomfim et al., 2018 ; Emer et al., 2019 ). Compared with large habitat patches, small habitat patches are unable to support the survival of most large-bodied species owing to their lower food quality and greater interspecific competition ( Hart et al., 2017 ; Ferretti and Fattorini, 2021 ). Consequently, the seed dispersal networks dominated by these large-bodied species are disrupted, thus affecting subsequent plant species recruitment ( Bregman et al., 2016 ; Donoso et al., 2016 ).…”