Detecting and modelling delayed density-dependence in abundance time series of a small mammal (Didelphis aurita)

Abstract

We study the population size time series of a Neotropical small mammal with the intent of detecting and modelling population regulation processes generated by density-dependent factors and their possible delayed effects. The application of analysis tools based on principles of statistical generality are nowadays a common practice for describing these phenomena, but, in general, they are more capable of generating clear diagnosis rather than granting valuable modelling. For this reason, in our approach, we detect the principal temporal structures on the bases of different correlation measures, and from these results we build an ad-hoc minimalist autoregressive model that incorporates the main drivers of the dynamics. Surprisingly our model is capable of reproducing very well the time patterns of the empirical series and, for the first time, clearly outlines the importance of the time of attaining sexual maturity as a central temporal scale for the dynamics of this species. In fact, an important advantage of this analysis scheme is that all the model parameters are directly biologically interpretable and potentially measurable, allowing a consistency check between model outputs and independent measurements.

Influência de fatores endógenos e exógenos na dinâmica populacional de dois pequenos mamíferos em uma área de cerrado denso na Estação Ecológica do Panga (Uberlândia/MG, Brasil)

“…As observed in previous studies with small mammals in tropical areas, density was a main factor regulating population dynamics of G. agilis and R. mastacalis, through increased intraspecific competition Brigatti et al 2016). Indeed, we found density-dependent effects on both species recruitment, supporting previous studies that suggest a stronger impact of density on recruitment/fecundity than on survival rates of small mammals .…”

“…In the Southern Hemisphere, while marsupials present a fluctuation pattern related to seasonality and food availability (Tyndale-Biscoe 2005; Martins et al 2006;, rodents generally show irregular and non-cyclical fluctuations, resulting from stochastic variation in environmental and climatic factors . Hence, most long-term studies in the tropics suggest that marsupial population dynamics are mainly determined by density dependence (direct or delayed), while exogenous factors, such as local climate, play a relatively less important role in the demography of these populations (Ferreira et al , 2020Brigatti et al 2016). In contrast, rodent outbreaks are suggested to be triggered by the indirect effects of rainfall on the availability of food resources and shelter in tropical ecosystems Gallardo e Mercado 1999;Bovendorp et al 2020).…”

The Program for Biodiversity Research in Brazil: The role of regional networks for biodiversity knowledge, dissemination, and conservation

“…Researchers have also undertaken studies of environmental impacts of extensive infrastructure programs (Bobrowiec & Tavares 2017), fire ecology (e.g. Fadini & Lima 2012), island biogeography and metapopulation dynamics (Carvalho et al 2008, Cintra et al 2013, methods in ecology (Norris et al 2014, Madalozzo et al 2017, Fontana et al 2018, population ecology (Brigatti et al 2016, Ferreira et al 2016, population genetics and phylogeography (Collevatti et al 2014, Melo et al 2016, Vitorino et al 2016 PPBio has produced several books about the ecology of Brazilian ecosystems and identification guides for specific groups of funga, fauna, and flora (e.g. Costa et al 2011, Baccaro et al 2015, Iop et al 2016, Peixoto et al 2016.…”

Multi-scale spatial models reveal the interplay of weather and habitat effects on cold-water fish

“…Our model can be used for optimal survey designs concerning the distribution of single-and multi-pass sites (Leach et al, 2022). Finally, other extensions of our analytical framework may include more complex population mechanisms such as density-regulated growth (Brigatti et al, 2016) and inter-specific competition (Morita, 2018), where longer time-series are available.…”