Dados do Trabalho

TÍTULO

NATIVE FOREST AND RIVERINE AREAS AS ALLIES TO LESSEN THE SPREAD OF THE EUROPEAN HARE (LEPUS EUROPAEUS: LAGOMORPHA, LEPORIDAE) IN THE NEOTROPICS

Resumo

Biological invasions are one of the main threats to biodiversity conservation. Although not every introduction of species results in invasions, aliens species commonly cause severe impact both to humans and wildlife. In the Neotropics, the exotic European hare (Lepus europaeus) was introduced in the late 19th century in Argentina and Chile and has since rapidly expanded its geographical distribution northwards, currently occurring throughout the Brazilian south and southeast. Although European hare is a farmland specialist in its native habitat (i.e., continental Europe), how this species is using the Neotropical habitats remains unexplored. Furthermore, because European hare represents a potential threat to native habitat and species in the Neotropics, we need to understand what exactly drives its occurrence in order to plan effective control measures. We address this information gap assessing predictors of the occupancy of the European hare near the northward expansion front of this invader in the Neotropics, the northeast of São Paulo state, in southeastern Brazil. We obtained occurrence data on this species in 205 sampling sites randomly located inside (101 sites) and outside (104 sites) protected areas, during the dry season of 2013 and 2014. We sampled each site with one camera-trap during 30 days. Additionally, we searched for lagomorph tracks two times, during camera set up and removal, respectively, in a 200-m long transect (uncertain method). We assessed several native and agricultural habitat covariates, including forest edges, as predictors of occupancy (ψ) using single season single species occupancy models accounting for false positive detections. The model selection was based on Akaike Information Criterion, corrected for small samples (AICc). We found strong evidence of false positive detections errors on track identification of European hare. If not accounted for, these errors inflate five times the estimated ψ. We also found that native forest (NatF) and hydrographic density (Hyd_dens) best explained ψ, both with negative and well-estimated effects (NatF = -0.03, SE = 0.01; CI = -0.05 to -0.01 and Hyd_dens = -0.09, SE = 0.04; CI = -0.16 to -0.02, respectively). This study demonstrates that sampling hare tracks is highly prone to misidentification, leading to false positive detections that, in turn substantially bias occupancy estimation. The negative effects of native forests and riverine areas on the focal species are consistent with other studies. In its original habitat, the European hare is known to avoid highly wooded areas, selecting edges (< 20 m) for resting but avoiding them altogether when in activity. The negative effect of riverine areas may be related to higher predation risk there since ocelots, a potential hare predator, are more abundant in these areas them elsewhere. Our study indicates that native forests existing both inside and outside protected areas, particularly those associated with watercourses, could lessen the spread of this exotic species in the Neotropics. 

Palavras-chave

biological invasion; occupancy modeling; false positive; habitat use; occurrence.

Financiamento

This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP 2011/22449-4). We would like to thank Dr. Aurelio Fontes for its support with Geographic Information Systems and mapping; the Instituto Geográfico Cartográfico do Estado de São Paulo (IGC) for providing orthophotomosaic images; the University of São Paulo, the International Paper Co. of Brazil, the Instituto Florestal, and the Fundação Florestal for logistical support and CNPq, CAPES and FAPESP for providing scholarship to NP during his Master and PhD (130198/2014-5, 1772007 and 2018/11788-1, respectively).