Camila Righetto Cassano

Landscape and farm scale management to enhance biodiversity conservation in the cocoa producing region of southern Bahia, Brazil

In southern Bahia, Brazil, large land areas are used for the production of cocoa (Theobroma cacao), which is predominantly grown under the shade of native trees in an agroforestry system locally known as cabruca. As a dominant forest-like landscape element of the cocoa region, the cabrucas play an important role in the conservation of the region’s biodiversity. The purpose of this review is to provide the scientific basis for an action plan to reconcile cocoa production and biodiversity conservation in southern Bahia. The available research collectively highlights the diversity of responses of different species and biological groups to both the habitat quality of the cabrucas themselves and to the general characteristics of the landscape, such as the relative extent and spatial configuration of different vegetation types within the landscape mosaic. We identify factors that influence directly or indirectly the occurrence of native species in the cabrucas and the wider landscape of the cocoa region and develop recommendations for their conservation management. We show that the current scientific knowledge already provides a good basis for a biodiversity friendly management of the cocoa region of southern Bahia, although more work is needed to refine some management recommendations, especially on shade canopy composition and density, and verify their economic viability. The implementation of our recommendations should be accompanied by appropriate biological and socioeconomic monitoring and the findings should inform a broad program of adaptive management of the cabrucas and the wider cocoa landscape.

Assessing the utility of statistical adjustments for imperfect detection in tropical conservation science

Summary In recent years, there has been a fast development of models that adjust for imperfect detection. These models have revolutionized the analysis of field data, and their use has repeatedly demonstrated the importance of sampling design and data quality. There are, however, several practical limitations associated with the use of detectability models which restrict their relevance to tropical conservation science. We outline the main advantages of detectability models, before examining their limitations associated with their applicability to the analysis of tropical communities, rare species and large‐scale data sets. Finally, we discuss whether detection probability needs to be controlled before and/or after data collection. Models that adjust for imperfect detection allow ecologists to assess data quality by estimating uncertainty and to obtain adjusted ecological estimates of populations and communities. Importantly, these models have allowed informed decisions to be made about the conservation and management of target species. Data requirements for obtaining unadjusted estimates are substantially lower than for detectability‐adjusted estimates, which require relatively high detection/recapture probabilities and a number of repeated surveys at each location. These requirements can be difficult to meet in large‐scale environmental studies where high levels of spatial replication are needed, or in the tropics where communities are composed of many naturally rare species. However, while imperfect detection can only be adjusted statistically, covariates of detection probability can also be controlled through study design. Using three study cases where we controlled for covariates of detection probability through sampling design, we show that the variation in unadjusted ecological estimates from nearly 100 species was qualitatively the same as that obtained from adjusted estimates. Finally, we discuss that the decision as to whether one should control for covariates of detection probability through study design or statistical analyses should be dependent on study objectives. Synthesis and applications. Models that adjust for imperfect detection are an important part of an ecologists toolkit, but they should not be uniformly adopted in all studies. Ecologists should never let the constraints of models dictate which questions should be pursued or how the data should be analysed, and detectability models are no exception. We argue for pluralism in scientific methods, particularly where cost‐effective applied ecological science is needed to inform conservation policy at a range of different scales and in many different systems.

Conservation in tropical landscape mosaics: the case of the cacao landscape of southern Bahia, Brazil

A recent debate has contrasted two conservation strategies in agricultural landscapes; either “land sparing” farm development combining intensive production practices with forest set-asides, or “wildlife-friendly” farming with greater on-farm habitat value but lower yields. We argue that in established mosaic landscapes including old cacao production regions where natural forest has already been reduced to relatively small fragments, a combination of both strategies is needed to conserve biodiversity. After reviewing the evidence for the insufficiency of either strategy alone if applied to such landscapes, the paper focuses on the cacao production landscape of southern Bahia, Brazil, once the world’s second largest cacao producer. Here, small remaining areas of Atlantic Forest are embedded in a matrix dominated by traditional cacao agroforests, resulting in a landscape mosaic that has proven favorable to the conservation of the region’s high biodiversity. We show that current land use dynamics and public policies pose threats but also offer opportunities to conservation and describe a three-pronged landscape conservation strategy, consisting of (i) expansion of the protected areas system, (ii) promotion of productive yet biodiversity-friendly cacao farming practices, and (iii) assistance to land users to implement legally mandated on-farm reserves and voluntary private reserves. We discuss recent experiences concerning the implementation of this strategy, discuss likely future scenarios, and reflect on the applicability of the Bahian experience to biodiversity rich cacao production regions elsewhere in the tropics.

Domestic dog invasion in an agroforestry mosaic in southern Bahia, Brazil.

Although the value of agroforests for biodiversity conservation has been frequently highlighted, little is known about the susceptibility of this production system to biological invasions. Drawing on a camera-trap dataset obtained in 39 sites in an agroforestry mosaic in southern Bahia, Brazil, we investigated whether the conversion of native forests into agroforests and management intensification in agroforests favor the invasion by the most common carnivore worldwide, the domestic dog. We also examined whether domestic dog invasion is more associated with human activity in agroforests than in native forests. While the number of invading dogs was higher in agroforests than in native forests (11 compared to 7 dogs per site), management intensification in agroforests led to a higher mean number of visits per dog. In both habitats (not only agroforests) visits by domestic dogs tended to be concentrated on times of the day (around midday) and days of the week (Monday to Saturday) when there is greater human activity. Despite being permeable to native species, agroforests may act as sink or trap areas given their higher susceptibility to invasion, potentially limiting the value of this production system for biodiversity conservation. Moreover, local management intensification, which has been expanding worldwide, increases the intensity of such invasions, further decreasing the value of agroforests. The value of agroforestry mosaics for conservation thus depends on the management of invasive species and at least in the case of dogs, one of the most common and widely distributed invasive species, this management should focus on the habits and behavior of humans.

Evaluating Landscape Suitability for Golden-Headed Lion Tamarins (Leontopithecus Chrysomelas) and Wied's Black Tufted-Ear Marmosets (Callithrix Kuhlii) in the Bahian Atlantic Forest

In southern Bahia, Brazil, rapid deforestation of the Atlantic Forest threatens a variety of endemic wildlife, including the Endangered golden-headed lion tamarin (GHLT; Leontopithecus chrysomelas) and the Near Threatened Wieds black-tufted-ear marmoset (Wieds marmoset; Callithrix kuhlii). Identifying high quality areas in the landscape is critical for mounting efficient conservation programs for these primates. We constructed ecological niche models (ENMs) for GHLTs and Wieds marmosets using the presence-only algorithm Maxent to (1) locate suitable areas for each species, (2) examine the overlap in these areas, and (3) determine the amount of suitable habitat in protected areas. Our models indicate that 36% (10, 659 km2) of the study area is suitable for GHLTs and 53% (15, 642 km2) for Wieds marmosets. Suitable areas were strongly defined by presence of neighboring forest cover for both species, as well as annual temperature range for GHLTs and distance from urban areas for Wieds marmosets. Thirty-three percent of the landscape (9,809 km2) is overlapping suitable habitat. Given that the focal species form mixed-species groups, these areas of shared suitability may be key locations for preserving this important behavioral interaction. Protected areas contained 6% (651 km2) of all suitable habitat for GHLTs and 4% (682 km2) for Wieds marmosets. All protected areas were suitable for the focal species, excepting Serra do Conduru, which had low suitability for GHLTs. Our results highlight that suitable habitat for GHLTs and Wieds marmosets is limited and largely unprotected. Conservation action to protect additional suitable areas will be critical for their persistence.

Human behaviors determine the direct and indirect impacts of free-ranging dogs on wildlife

Dogs (Canis familiaris) are among the most abundant and widely distributed carnivores worldwide, and their presence can have negative impacts on native fauna. This study investigated the invasion of cacao agroforests by free-ranging dogs in Brazil. By monitoring the behavior of dogs using direct observations, we assessed whether direct (chasing and predation) and indirect (urine and fecal deposition) interactions with wildlife are more common when dogs enter the agroforests with humans than when they stay outside. We also compared the time that dogs spent inside versus outside the agroforests, and estimated their areas of use. The dogs (n = 10) spent a small fraction of the time without their owners, and only when moving inside the cacao agroforests. The dogs fed and rested more in open habitats and house surroundings than in agroforests, but they were more active and depredated wildlife exclusively in the latter. Kernel estimates of space use at the 50% and 95% levels ranged from 1 to 46 ha and 6 to 202 ha, respectively. Most of the area used by dogs was within cacao agroforest, while core areas were concentrated near human residences and in places of owner permanence in cacao agroforest. Human movement was a key determining factor in the use of space by the dogs. Changes to human behaviors toward their dogs must be considered if the direct and indirect impacts of dogs on wildlife are to be mitigated.