La mastofauna nativa como indicador de efectividad en el corredor biológico río Carcarañá, Sur de Santa Fe, Argentina / The native mastofauna as an indicator of effectiveness in the biological corridor Carcarañá river, south of Santa Fe, Argentina

Abstract

In the south of the province of Santa Fe, the region presents a degree of subdivision and use of the ground that modified its original aspect, becoming a plain where the grain and oilseed crops predominate. The communities of wild mammals are increasingly threatened by this development, which is leading to the limit of fragmentation and loss of habitat. The objective of this work is to show the influence of the Carcarañá River on native mammals and its importance as a biological corridor. For this purpose, the area of study was the Carcarañá River basin in Santa Fe province. Within this area, five sampling zones were established (distant from each other by 50 km), both on the margin of the Carcarañá River and its tributaries. From this, three transects of 3 km in length were established in each study zone, taking into account that the first one is located on the margin of the river/tributary, while the remaining ones are parallel to it with a distance of 5 and 10 km respectively in order to generate a gradient. The field work was carried out during two consecutive years (2018-2019), in a seasonal manner. The methodology used was the collection of indirect evidence (footprints and faults) and the collection of information from direct evidence (sightings). The transect tours were carried out on foot, during the daytime hours and at an average speed of one km/h. To obtain complete parameters of the diversity of species in each transect, the number of species and their representativeness were quantified. For this purpose, it was established the specific richness (S) which refers to the number of species registered for each transect and its equity. The latter was calculated from the Shannon-Wiener function. With a sampling effort of 80 days of field work and 360 km of transects, it was possible to obtain a specific richness (S) of 12 species for the total of the transects located on the banks of the Carcarañá River ( Lutreolina crassicaudata, Didelphis albiventris, Chaetophractus villosus, Pseudalopex gymnocercus, Puma concolor, Puma yaguaroundi, Leopardus geoffroyi, Leopardus colocolo, Conepatus chinga, Galictis cuja, Hidrochoerus hydrochaeris and Myocastor coypus ) with a diversity index of H' = 2. 79. For the sum of the species registered in the transects located 5km from the river, the specific richness was 5 species ( D. albiventris, C. villosus, P. gymnocercus, C. chinga and G. cuja ) with a diversity index (H')= 0.94. Finally, the sum of species registered for the transects located 10km from the river was also 5 species with a somewhat lower diversity (H'= 0.63). Although incipient as a process and premature to test conclusive results, the evidence that biological corridors in areas widely disturbed by anthropogenic activity are a tool that contributes to the recovery of favorable environmental conditions for native mammals, is consolidated as the information generated ratifies the initial hypothesis about the value of biological corridors as a tool for biodiversity conservation.