Small rodent abundance and rainfall data

<p><span>Rodent outbreaks or irruptions in semiarid Chile are associated with rainfall pulses driven by the El Niño Southern Oscillation (ENSO). During the last decade, </span><span>north-central Chile has experienced an almost uninterrupted sequence of dry years, the so-called megadrought, which had led to a new ecological situation in this region. We employ a diagnostic approach to analyze the abundance of data regarding two rodent species, <em>Phyllotis</em> <em>darwini</em> and <em>Abrothrix</em> <em>olivacea</em>, using a 33-yr time series spanning from 1987 to 2019. Our population dynamic models provide evidence of competitive interactions within and among both species of rodents. This result is novel since rainfall variability influences the degree of interspecific competition and is asymmetric. The diagnostic approach used here offers a way to develop simple population models that are useful for understanding the causes of population fluctuations and for predicting population changes under a climate change scenario. </span></p>