Assessing the conservation value of secondary savanna for large mammals in the Brazilian Cerrado

Abstract

Debate about the conservation value of secondary habitats has tended to focus on tropical forests, increasingly recognizing the role of secondary forests for biodiversity conservation. However, there remains a lack of information about the conservation value of secondary savannas. Here, we conducted a camera trap survey to assess the effect of secondary vegetation on large mammals in a Brazilian Cerrado protected area, using a single‐season occupancy framework to investigate the response of individual species (species‐level models) and of all species combined (community‐level models). In addition, we investigated the cost effectiveness of different sampling designs to monitor globally threatened species in the study area. At the community level, savanna that regenerated from eucalyptus plantation had similar occupancy estimate as old growth areas. At the species level, none of the ten species individually assessed seemed to respond to succession stage, with greater support for the effect of other covariates on occupancy, such as distance from water and vegetation physiognomy. These results demonstrate that secondary vegetation does not appear to negatively impact large mammals in the study area and suggest that, given a favorable context, Cerrado mammals can recolonize and use secondary savannas that regenerated from clearcut. However, our study area should be considered a best‐case scenario, as it retained key ecological attributes of high‐value secondary habitats. Our simulations showed that a sampling design with 60 camera trap sites surveyed during nine occasions is appropriate to monitor most globally threatened species in the study area, and could be a useful starting point for new monitoring initiatives in other Cerrado areas.

A before−after assessment of the response of mammals to tourism in a Brazilian national park

“…Although adequate survey design might not fully eliminate imperfect detection, it can minimize variation in the detection probability that would affect the results. In our design, two features limited variation in the detection probability between sampling sites and survey periods: (1) we surveyed only pre-existing trails, avoiding the variation in detection between on- and off-trail sites, which is known to affect mammals in the region (Ferreira et al, 2017), and (2) at each site, camera traps were always deployed in the same tree, at the same height and facing the same direction during every survey, limiting the spatial and deployment effects on detection probability. Furthermore, we do not claim that a change in probability of trail use is driven necessarily by a change in animal abundance; instead, we interpret this as a metric reflecting the intensity of trail use by the species assessed, an approach that has been adopted in similar studies (Muhly et al, 2011; Blake et al, 2017; Kays et al, 2017; Ngoprasert et al, 2017).…”

Strict protected areas are essential for the conservation of larger and threatened mammals in a priority region of the Brazilian Cerrado

“…Therefore, via careful study design and statistical control of confounding variables we accounted for contextual factors that could potentially affect the outcome of interest but were not directly related to protection, such as distance to towns, roads, and water sources, as well variation in vegetation. These factors have a considerable overlap with the ones used by Carranza et al (2014) to investigate PA effectiveness in avoiding Cerrado deforestation and are known to influence the occurrence of Neotropical mammals (Ferreira et al, 2017;Nagy-Reis et al, 2017;Pinho et al, 2017). In this study, we treated strict PAs as the intervention and APAs as the counterfactual.…”

When the blanket is too short: Potential negative impacts of expanding indigenous land over a national park in a high priority area for conservation

“…However, the mere presence of humans and the associated noises and smells, as well the presence of domestic dogs, may be enough to create an unfavourable buffer zone for collared peccaries around settlements, in practice reducing the amount of habitat available for the species. I acknowledge that not all species will respond similarly to anthropogenic pressure, but the effect on collared peccary is a plausible model of what may be happening to rare and threatened mammal species that occur in the region, such as white-lipped peccary (Tayassu pecari), giant anteater (Myrmecophaga tridactyla), and bush dog (Speothos venaticus) (Ferreira et al, 2017;Ferreira and Oliveira, 2014), but for which there was not enough data for analysis.…”

“…for R (R Development Core Team, 2015) and following similar procedures as described inFerreira et al (2017). To obtain variables for this analysis, I used the software QGIS to extract Euclidian distances from each camera trap site to the nearest river, main road, CPNP's border and human settlement (regardless of ethnicity).…”