Top predator dynamics in suburban agro-ecosystems: their role in crop consumer regulation – TOP_PRED

Due to the current biodiversity collapse, especially in agroecosystems suffering from intense anthropogenic pressures, it is crucial to conduct inter-disciplinary research considering the main ecological and societal drivers of functional disturbances (e.g., habitat degradation/fragmentation, human practices) to anticipate and mitigate their impacts on ecosystem functioning and services.
Our project treats the trophic interactions between two predominant meso-predators acting as top-predators in agroecosystems, cats (domestic species) and foxes (pest species), which sometimes generate opposing human perceptions and practices depending on the predator status and a priori insights. Changes in predator distribution, density, and trophic patterns can strongly modify predation pressure on prey species (e.g. potential pests) and thus disrupt ecosystem structure (e.g., species over- or under-abundance), functioning (e.g., regulation, predation release), and ecosystem services (e.g., crop production). We will investigate three multidisciplinary and complementary axes to quantify the main trophic interactions and evaluate predator regulation services of potential pest prey over time, and to quantify the demographic consequences of stakeholder perceptions and practices on predators and evaluate possible cascading effects. The first axe comprises three tasks to evaluate predator diet, habitat use, and prey densities: 1) analyzing predator diet (scat macro and microscopic analyses, metabarcoding) using variables like seasons, prey density, and habitat to identify the main trophic interactions and external drivers that structure agroecosystem trophic webs; 2) individualizing scats using predator genetic fingerprints (diet and population genetics studies) to detect potential trophic “personalities” and complete our estimations of demographic parameters and habitat use with genetic CMR; and 3) using GPS collars and georeferenced hair and camera traps to detect potential “personalities” in habitat use. In the second axe, we will built dynamics and predictive trophic network models and test the potential trajectories of predator and prey populations given environmental constraints and stakeholder practices. Three steps will be used to obtain the most accurate prospective scenarios: 1) improving our candidate discretized deterministic models implemented and validated with accurate literature and field data over 5 years; 2) introducing stochastic variables; and 3) developing individual-based models. We will then validate and compare the ability of each model to predict predator densities and distributions as well as their impacts on main prey population dynamics. The third axe focuses on stakeholder perceptions and practices that influence predator dynamics. Three tasks aim to optimize collaborative management and refine the previous models: 1) identifying local community-predator interactions to better grasp the perceptions and practices of different stakeholders; 2) developing participative sciences with stakeholders to reinforce collaborations with a shared objective (improving ecosystem functioning and services); and 3) constructing collaborative management scenarios to promote the adaptive capacity of socio-ecological systems to optimize prospective actions. Our outstanding and original project simultaneously focuses on different scales of investigation (individual, population, species, and community) and combines fundamental ecology (population dynamics, behavioral ecology, and trophic networks), applied ecology (conservation biology, crop consumer management, ecosystem services), and social sciences (nature perceptions and animal-human interactions) in an interdisciplinary approach (biology, mathematics, and social sciences) to provide new scientific insights, prospective models, and collaborative guidelines to maintain/increase biodiversity in agroecosystems and improve their functioning and associated ecosystem services.