Estimating carnivore community structures

José Jiménez,Luis Mariano González,Juan Carlos Nuñez-Arjona,José Vicente López-Bao,Carmen Rueda,Jaime Muñoz-Igualada,Francisco García-Domínguez

doi:10.1038/srep41036

José Jiménez, Luis Mariano González + Show 5 more

Open Access

https://doi.org/10.1038/srep41036

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Abstract

Obtaining reliable estimates of the structure of carnivore communities is of paramount importance because of their ecological roles, ecosystem services and impact on biodiversity conservation, but they are still scarce. This information is key for carnivore management: to build support for and acceptance of management decisions and policies it is crucial that those decisions are based on robust and high quality information. Here, we combined camera and live-trapping surveys, as well as telemetry data, with spatially-explicit Bayesian models to show the usefulness of an integrated multi-method and multi-model approach to monitor carnivore community structures. Our methods account for imperfect detection and effectively deal with species with non-recognizable individuals. In our Mediterranean study system, the terrestrial carnivore community was dominated by red foxes (0.410 individuals/km2); Egyptian mongooses, feral cats and stone martens were similarly abundant (0.252, 0.249 and 0.240 individuals/km2, respectively), whereas badgers and common genets were the least common (0.130 and 0.087 individuals/km2, respectively). The precision of density estimates improved by incorporating multiple covariates, device operation, and accounting for the removal of individuals. The approach presented here has substantial implications for decision-making since it allows, for instance, the evaluation, in a standard and comparable way, of community responses to interventions.

Highlights

Management goals commonly rely on information about the abundance of species
Considering the encounter histories for each species, we were able to estimate the densities of red fox (Vulpes vulpes), stone marten (Martes foina), European badger (Meles meles), Egyptian mongoose (Herpestes ichneumon), common genet (Genetta genetta) and feral cat (Felis catus)
The spatially explicit capture-recapture (SCR) approach was only used with feral cats (55 photographic events, six of which were discarded because of very poor quality images, and captures with extraction), the SMR approach was used for red fox, stone martens, badgers and common genets, whereas the spatial count (SC) was used for Egyptian mongooses (77 events of unmarked individuals)

Summary

Introduction

Management goals commonly rely on information about the abundance of species. But monitoring is still one of the most controversial issues when managing wildlife[1,2]. Monitoring has traditionally followed a species-specific approach; in recent times, management interventions oriented to ecosystem functioning perspectives demands reliable estimates of community-level structures, including density estimates of entire guilds[3]. Estimates on carnivore community structures (here we refer to the number of species present and their abundance) are still very rare[12]. The use of non-spatially explicit analytical procedures has been questioned because of overestimation problems in density estimates[17]. This issue has been recently overcome with the development of spatially explicit approaches[15]. Only recently have detection probabilities been accounted for (in the absence of individual marks, detection rates confound abundance and detectability)[24,25]

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