Conservation strategies for endangered arable plant Euphorbia gaditana

Abstract

Fragmentation and habitat loss are considered among the most important threats to biodiversity. More precisely, transformation of natural habitats into farmlands has been identified as one of the primary causes of plant species extinction. Therefore, understanding the effects of habitat fragmentation is crucial to the successful conservation of threatened species. Metapopulation modeling is one of the prospective tools used in conservation biology to evaluate long‐term survival in fragmented landscapes. In this work, we applied a metapopulation approach to the conservation of the rare plant Euphorbia gaditana Coss., an endangered species growing on the margins of crops in southern Spain. The species is threatened due to herbicide application and intensification of cultivation, which results in a highly patchy distribution, with more than 50 patches of habitat across three separate networks of patches. We used IFM (Incidence Function Modeling) to compare the relative effectiveness of four conservation management scenarios and the effect of three threat scenarios on the risk of extinction of the species. The results of our simulations of population dynamics under plausible management scenarios will aid conservation decision‐making, for example, allowing priority conservation areas to be identified or assessing the effect of future reintroductions.

Broadening applications of stochastic patch occupancy models over three decades

“…Adaptations in model structure can allow more factors to affect the colonisation and extinction probabilities of patches and may ameliorate some of the perceived limitations of SPOMs (or of metapopulation models in general). Half of our study cases used a SPOM potentially applicable to all metapopulations (i.e., the IFM, SRLM or PRM), with the IFM being the most used over all (41%; e.g., George et al., 2013; Rabasa et al., 2022). The modified versions of these models constituted 18% of cases.…”

“…Compared with other ways of projecting species' distributions under climate and land use change (e.g., Species Distribution Models, Velazco et al, 2020), SPOMs stand out because they include a species' dispersal ability and populations' extinction risk, which are both critical aspects for conservation planning (Thrall et al, 2000). Lastly, SPOM parametrisation is possible with information that is often more accessible than that required for other models (Rabasa et al, 2022). The colonisation and extinction rates needed for SPOMs have often been parametrised from a single snapshot of the occupancy state of a set of patches (based on their area and isolation, although more data may be needed if the SPOM includes additional factors or cannot be assumed to be at equilibrium).…”

“…Lastly, SPOM parametrisation is possible with information that is often more accessible than that required for other models (Rabasa et al., 2022). The colonisation and extinction rates needed for SPOMs have often been parametrised from a single snapshot of the occupancy state of a set of patches (based on their area and isolation, although more data may be needed if the SPOM includes additional factors or cannot be assumed to be at equilibrium).…”