Abstract

The ecology of leeches worldwide has been scarcely studied, with the ecology of Neotropical leeches remaining highly unknown. Americobdella valdiviana, an endemic, carnivorous, and giant leech that inhabits the Valdivian evergreen forest in southern Chile, an ecosystem that has experienced an increase in its net loss from 3.6% to 12% in the last decades due to various human activities. Here, we combined citizen science with species distribution models (SDM) to analyze (i) the effect of habitat variables with the abundance A. valdiviana, (ii) the distribution range, (iii) the habitat loss and fragmentation of A. valdiviana, and (iv) their conservation status. First, we asked each user or scientist for the observed relative abundance and a series of environmental variables, which were then correlated by using Generalized Linear Models. Then, distribution ranges were estimated using SDM, which was combined with multiannual forest cover maps to identify habitat loss and fragmentation between 2000 and 2018. Finally, we used IUCN criteria to evaluate the conservation status of this species. Abundance was related mainly to the canopy coverage, while suitability was positively associated to temperature seasonality and canopy cover. Suitability was higher in forests with levels of primary productivity. We found that the north and center zones of the species range experienced high habitat loss and fragmentation. Under IUCN Red List criteria, we qualified this species as endangered. Our results support that the combination of citizen science, SDM, and spatial analysis at local and biogeographical scales can inform conservation actions of poorly known and threatened macroinvertebrate fauna.