Long term variations in Oxymycterus rufus (Rodentia, Sigmodontine) abundance in relation to climate change in Pampean agroecosystems.

CALFAYAN L.M.; GUIDOBONO J.S.; FRASCHINA, J; CAVIA R; BUSCH M; GOROSITO, I.L

Arusha

Conferencia; 7th International Conference on Rodent Biology and Management; 2022

7th International Conference on Rodent Biology and Management

Long term variations in Oxymycterus rufus (Rodentia, Sigmodontine) abundance in relation to climate change in Pampean agroecosystems L. M. Calfayan1, R. Cavia1, J. Fraschina1, J. S. Guidobono1, I. L. Gorosito1, M. Busch1 1IEGEBA (UBA-CONICET), Ciudad Universitaria, Buenos Aires, Argentina mbusch@ege.fcen.uba.ar Oxymycterus rufus is a subtropical rodent which extends in South America from Paraguay and Brazil to central Argentina. In the southern portion of its range, it is restricted to riparian and coastal habitats with mild environmental conditions. In recent years there was an increase of captures in longitudinal habitats of agroecosystems along crop field borders and abandoned railways. We hypothesize that this increase is associated with changes in climate, with milder temperature conditions. The goal of this work was to assess the abundance changes of this species over 30 years in longitudinal habitats of the Pampas region and their relation to the type of habitat, distance to watercourses and meteorological data. Rodent abundance was recorded from 1984 to 2014 from capturerecapture trappings conducted by the Population Ecology Group (IEGEBA, UBA-CONICET) and published data. Meteorological data were obtained online. We selected variables associated to temperature and precipitation that may influence O. rufus survival and reproduction: maximum and minimum temperature, the number of hours with temperature under 0°C, number of days with probability of frost (minimum temperature < 0°C), maximum number of consecutive days with probability of frost, mean monthly water excess, number of days with water excess, and ENSO Index. The effect of habitat (crop field border versus railway embankment), distance to riparian habitats and meteorological variables on O. rufus abundance along the study period was evaluated through forward stepwise regression with generalized linear models. O. rufus was absent in captures until 1999, and its abundance was gradually increasing until it became codominant in the rodent community, but the causes of this increase remain unclear, since there was not a consistent relation with changes in meteorological variables. Studies about the effects of land use change, interactions with other species or adaptations to agroecosystems are needed.