2 research outputs found
Ecological traits and the spatial structure of competitive coexistence among carnivores
Competition is a widespread interaction among carnivores, ultimately manifested through one or more dimensions of the species' ecological niche. One of the most explicit manifestations of competitive interactions regards spatial displacement. Its interpretation under a theoretical context provides an important tool to deepen our understanding of biological systems and communities, but also for wildlife management and conservation. We used Bayesian multispecies occupancy models on cameraâtrapping data from multiple sites in Southwestern Europe (SWE) to investigate competitive interactions within a carnivore guild, and to evaluate how species' ecological traits are shaping coexistence patterns. Seventeen out of 26 pairwise interactions departed from a hypothesis of independent occurrence, with spatial association being twice as frequent as avoidance. Association behaviors were only detected among mesocarnivores, while avoidance mainly involved mesocarnivores avoiding the apex predator (n = 4) and mesocarnivoreâonly interactions (n = 2). Body mass ratios, defined as the dominant over the subordinate species body mass, revealed an important negative effect ( ÎČË=â0.38;CI95=â0.81â0.06 ) on coâoccurrence probability, and support that spatially explicit competitive interactions are mostly expressed by larger species able to dominate over smaller ones, with a threshold in body mass ratios of ~4, above which localâscale intraguild coexistence is unlikely. We found a weak relationship between pairwise trophic niche overlap and the probability of coexistence ( ÎČË=â0.19;CI95=â0.580.21 ), suggesting that competition for feeding resources may not be a key driver of competition, at least at the scale of our analysis. Despite localâscale avoidance, regionalâscale coexistence appears to be maintained by the spatial structuring of the competitive environment. We provide evidence that SWE ecosystems consist of spatially structured competitive environments, and propose that coexistence among nearâsized species is likely achieved through the interplay of âfacultativeâ and âbehavioralâ character displacements. Factors influencing carnivore coexistence likely include contextâdependent density and traitâmediated effects, which should be carefully considered for a sound understanding of the mechanisms regulating these communities.This study was funded by research projects CGL2009â10741, funded by the Spanish Ministry of Science and Innovation and EUâFEDER, and OAPN 352/2011, funded by the Spanish Organismo AutĂłnomo Parques Nacionales. P. Monterroso enjoyed a Ph.D. grant from the Fundação para a CiĂȘncia e a Tecnologia (FCT) (ref: SFRH/BD/37795/2007) and a postdoctoral fellowship by EUâFEDER funds through the Operational Programme for Competitiveness FactorsâCOMPETE and by National Funds through FCTâFoundation for Science and Technology (ref: UID/BIA/50027/2013, POCIâ01â0145âFEDERâ006821). F. DĂazâRuiz enjoyed a research contract âJuan de la Ciervaâ (ref: FJCIâ2015â24949) from the Spanish Ministry of Economy, Industry, and Competitiveness.Peer reviewe
Ecological traits and the spatial structure of competitive coexistence among carnivores
Competition is a widespread interaction among carnivores, ultimately manifested through one or more dimensions of the species' ecological niche. One of the most explicit manifestations of competitive interactions regards spatial displacement. Its interpretation under a theoretical context provides an important tool to deepen our understanding of biological systems and communities, but also for wildlife management and conservation. We used Bayesian multispecies occupancy models on cameraâtrapping data from multiple sites in Southwestern Europe (SWE) to investigate competitive interactions within a carnivore guild, and to evaluate how species' ecological traits are shaping coexistence patterns. Seventeen out of 26 pairwise interactions departed from a hypothesis of independent occurrence, with spatial association being twice as frequent as avoidance. Association behaviors were only detected among mesocarnivores, while avoidance mainly involved mesocarnivores avoiding the apex predator (n = 4) and mesocarnivoreâonly interactions (n = 2). Body mass ratios, defined as the dominant over the subordinate species body mass, revealed an important negative effect ( ÎČË=â0.38;CI95=â0.81â0.06 ) on coâoccurrence probability, and support that spatially explicit competitive interactions are mostly expressed by larger species able to dominate over smaller ones, with a threshold in body mass ratios of ~4, above which localâscale intraguild coexistence is unlikely. We found a weak relationship between pairwise trophic niche overlap and the probability of coexistence ( ÎČË=â0.19;CI95=â0.580.21 ), suggesting that competition for feeding resources may not be a key driver of competition, at least at the scale of our analysis. Despite localâscale avoidance, regionalâscale coexistence appears to be maintained by the spatial structuring of the competitive environment. We provide evidence that SWE ecosystems consist of spatially structured competitive environments, and propose that coexistence among nearâsized species is likely achieved through the interplay of âfacultativeâ and âbehavioralâ character displacements. Factors influencing carnivore coexistence likely include contextâdependent density and traitâmediated effects, which should be carefully considered for a sound understanding of the mechanisms regulating these communities.This study was funded by research projects CGL2009â10741, funded by the Spanish Ministry of Science and Innovation and EUâFEDER, and OAPN 352/2011, funded by the Spanish Organismo AutĂłnomo Parques Nacionales. P. Monterroso enjoyed a Ph.D. grant from the Fundação para a CiĂȘncia e a Tecnologia (FCT) (ref: SFRH/BD/37795/2007) and a postdoctoral fellowship by EUâFEDER funds through the Operational Programme for Competitiveness FactorsâCOMPETE and by National Funds through FCTâFoundation for Science and Technology (ref: UID/BIA/50027/2013, POCIâ01â0145âFEDERâ006821). F. DĂazâRuiz enjoyed a research contract âJuan de la Ciervaâ (ref: FJCIâ2015â24949) from the Spanish Ministry of Economy, Industry, and Competitiveness.Peer reviewe