Modeling of potential habitat suitability of Hippocamelus bisulcus: effectiveness of a protected areas network in Southern Patagonia

Introduction:Huemul(Hippocamelus bisulcus Molina)is the most threatened flag species of Southern Patagonia,where conservation efforts were not effective to avoid the retraction of its distribution area.Habitat quality modeling can assist to design better management strategies for regional conservation planning.The objective was to elaborate one habitat suitability map for huemul,defining the environmental characteristics at landscape level,and determining the distribution of the suitable habitat inside the current natural reserve network.Methods:We used a database of 453 records and explored 40 potential explanatory variables(climate,topographic,and landscape variables including human-related ones)to develop one habitat suitability map using the Environmental Niche Factor Analysis(ENFA)for Santa Cruz province(Argentina).We combined the outputs in a GIS project using different shapes,including the current natural reserve network.Results:We defined the potential habitat for huemul,where forest edges and ecotone zones(e.g.,mainly alpine environments)were the most important environmental variables,as well as some forest types(e.g.,Nothofagus pumilio).Habitat losses were found in the extreme potential distribution areas(northern and southern areas),probably related to the increasing ranch activities.The current natural reserve network maintains approximately half of the huemul potential habitat in Santa Cruz province,where National Parks presented the similar conservation importance than the Provincial natural reserves.Conclusions:Habitat suitability model for huemul can be used as a decision support system for new management strategies at different landscape levels to improve the current conservation efforts.

Improving the knowledge of plant potential biodiversity-ecosystem services links using maps at the regional level in Southern Patagonia

Background:Biodiversity supports multiple ecosystem services,whereas species loss endangers the provision of many services and affects ecosystem resilience and resistance capacity.The increase of remote sensing techniques allows to estimate biodiversity and ecosystem services supply at the landscape level in areas with low available data(e.g.Southern Patagonia).This paper evaluates the potential biodiversity and how it links with ecosystem services,based on vascular plant species across eight ecological areas.We also evaluated the habitat plant requirements and their relation with natural gradients.A total of 977 plots were used to develop habitat suitability maps based on an environmental niche factor analysis of 15 more important indicator species for each ecological area(n=53 species)using 40 explanatory variables.Finally,these maps were combined into a single potential biodiversity map,which was linked with environmental variables and ecosystem services supply.For comparisons,data were extracted and compared through analyses of variance.Results:The plant habitat requirements varied greatly among the different ecological areas,and it was possible to define groups according to its specialization and marginality indexes.The potential biodiversity map allowed us to detect coldspots in the western mountains and hotspots in southern and eastern areas.Higher biodiversity was associated to higher temperatures and normalized difference vegetation index,while lower biodiversity was related to elevation and rainfall.Potential biodiversity was closely associated with supporting and provisioning ecosystem services in shrublands and grasslands in the humid steppe,while the lowest values were related to cultural ecosystem services in Nothofagus forests.Conclusions:The present study showed that plant species present remarkable differences in spatial distributions and ecological requirements,being a useful proxy for potential biodiversity modelling.Potential biodiversity values change across ecological areas allowing to identify hotspots and coldspots,a useful tool for landscape management and conservation strategies.In addition,links with ecosystem services detect potential synergies and trade-offs,where areas with the lowest potential biodiversity are related to cultural ecosystem services(e.g.aesthetic values)and areas with the greatest potential biodiversity showed threats related to productive activities(e.g.livestock).

Forage offering and seasonal intake comparisons to evaluate European rabbit threat in Nothofagus forests of southern Patagonia

Background:The European rabbit(Oryctolagus cuniculus L.1758)was introduced into different regions of the world,generating significant trade‑offs that critically impacted native vegetation.Here,we evaluate the rabbit’s forage intakes in three vegetation types(forests,shrublands,and grasslands)along the four seasons in a temperate forest landscape in Southern Patagonia and discuss the potential threats over native vegetation.We formulated the following questions:(i)what is the forage offer at each vegetation type?(ii)what is the rabbit’s forage intake and how it varied across the seasons along the year?and(iii)which vegetation types and plant life forms were more used according to the rabbit’s forage intakes?Methods:We censused understory vegetation to characterize the forage offer at each vegetation type and determined seasonal dietary intakes using microhistological analysis of pellets.The plant species identified in the field were grouped according to life form classes(tree regeneration,shrubs,forbs,graminoids,orchids,ferns,bryophytes,and hemiparasites).Data were analysed through uni‑and multi‑variate analyses,determining relationships between forage offer and the rabbit’s forage intakes.Results:Forage intakes revealed changes in plant life form consumption across vegetation types,where intake pressure was considerably different for tree regeneration(p=0.001),graminoids(p=0.001),and hemiparasites(p=0.001).Besides,significant changes in consumption among seasons were detected for shrubs(p=0.001),ferns(p=0.030),and hemiparasites(p=0.002).Although many species play an important role in the rabbit’s forage intake networks(e.g.,Chiliotrichum diffusum,Holcus lanatus),the strongest intake linkages were found in exotic grasses(e.g.,Poa pratensis and Festuca sp.),native hemiparasites(e.g.,Misodendrum sp.),native shrubs(e.g.,Empetrum rubrum),and native trees(e.g.,Nothofagus sp.).The summer and autumn seasons presented higher intake compared to the winter and spring seasons.Furthermore,hemiparasites intake(e.g.,Misodendrum sp.)suggests that rabbits utilize different forage sources depending on the vegetation types.Conclusions:Rabbits regularly inhabit the forest,even though it is not their preferred vegetation type to live.Rabbit management entails isolating regions that are more favourable to intake and emphasizing the year’s season for rabbit control efforts.