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

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

Arusha

Congreso; 7th international conference of rodent biology and management; 2022

Oxymycterus rufus is a subtropical rodent which extends in South America from Paraguayand Brazil to central Argentina. In the southern portion of its range, it is restricted toriparian and coastal habitats with mild environmental conditions. In recent years therewas an increase of captures in longitudinal habitats of agroecosystems along crop fieldborders and abandoned railways. We hypothesize that this increase is associated withchanges in climate, with milder temperature conditions. The goal of this work was toassess the abundance changes of this species over 30 years in longitudinal habitats of thePampas region and their relation to the type of habitat, distance to watercourses andmeteorological 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 variablesassociated to temperature and precipitation that may influence O. rufus survival andreproduction: maximum and minimum temperature, the number of hours withtemperature under 0°C, number of days with probability of frost (minimum temperature< 0°C), maximum number of consecutive days with probability of frost, mean monthlywater excess, number of days with water excess, and ENSO Index. The effect of habitat(crop field border versus railway embankment), distance to riparian habitats andmeteorological variables on O. rufus abundance along the study period was evaluatedthrough forward stepwise regression with generalized linear models. O. rufus was absentin 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, sincethere was not a consistent relation with changes in meteorological variables. Studiesabout the effects of land use change, interactions with other species or adaptations toagroecosystems are needed.