Wild pig (Sus scrofa L.) occupancy patterns in the Brazilian Atlantic forest

Carla Grasiele Zanin Hegel,Luane Reis Dos Santos,Miguel Ângelo Marini,Mauro Pichorim

doi:10.1590/1676-0611-bn-2018-0719

Abstract

Abstract: Despite the great impacts of invasive wild pig (Sus scrofa) to natural ecosystems, habitat use by this species in the neotropics remains poorly studied. Here, we investigated the effects of local habitat and landscape covariates (vegetation types, running watercourses and roads) on occupancy patterns of wild pig in the Atlantic Forest of southern Brazil. We used single season occupancy modeling to estimate detection (p) and occupancy (ψ) probabilities, using 8-day camera-trap monitoring of 100 sampled sites. The cameras detected wild pig in 64 sites (naïve occupancy = 64 %). The four best models explained 72.7 % of the occupancy patterns, and the top model (with "water" variable) had a weight of 28.5 %. Even though none of the tested variables had high explanatory power of wild pig occupancy, the water variable had a negative effect trend (β = -1.124; SE = 0.734), with 59 % of occupancy when water was present and 82 % when it was absent around the sampling sites. Vestiges of the presence of wild pig in different vegetation types revealed that they used plantations of Pinus sp., native forests, and corn and oat crops. The occupation pattern shows that wild pig are generalist at our study site at the Atlantic Forest being found everywhere, raising ecological and economic concerns about the high potential negative effects of its invasion.

Highlights

Non-native and invasive species are found in almost all ecosystems worldwide, a number that has increased markedly in the last two decades (Blackburn et al 2011)
We detected a slight tendency for a negative effect of running watercourses and wetlands on wild pig occupation
This is opposite to expected since McClure et al (2015), in a macro-spatial study in the USA, found that both distance to water and landscape heterogeneity were important in their models, with localities far away from the water having lower occurrence of wild pig

Summary

Introduction

Non-native and invasive species are found in almost all ecosystems worldwide, a number that has increased markedly in the last two decades (Blackburn et al 2011). These accidentally or intentionally introduced species are causing several damages to native species (Vitule et al 2012), changes in community structure and in dynamics of natural ecosystems (Martin et al 2009) and even reduction in biological diversity (Chapin III et al 2000). Wild pig population growth and abundance can be determined by presence or absence of food resources (Jedrzejewska et al 1997; Honda 2009), landscape structure (Acevedo et al 2006) and climatic factors (Honda 2009)

Methods

Results

Conclusion