Present and future of Iris atrofusca populations in the Negev Desert analyzed by population viability analysis and species distribution modeling

A recovery plan for an imperiled plant species is impossible without good knowledge of population demography and biotic/abiotic effects on the latter. The aim of our study was to analyze to what extent the Negev populations of Iris atrofusca Baker (Iridaceae), a species endemic to Israel and Jordan, are threatened by the internal population dynamics, and the factors affecting it, including grazing and competition. We conducted a demographic population viability analysis to identify the most important life cycle stages and forecast the population future; and tested experimentally the effects of grazing and competition with a co-occurring Asphodelus ramosus on species growth and reproduction. In addition, we utilized species distribution modeling (SDM) to determine a potentially suitable species range, both under the current climate and the climate expected in the near future. After evaluating the long-term demographic trends of the Negev populations, the recommended conservation actions to prevent their disappearance were not congruent for two different parts of this region because both the population processes of reproduction and recruitment and the role of external factors affecting them differed between the sub-regions.