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Conservation scientists continue to debate the strengths and weaknesses of REDD+ as an instrument to slow greenhouse gas emissions in the developing world. We propose that general positions on this debate are less helpful than drawing lessons from specific investigations into the features of individual projects that make them successful or not. Here, focusing on a site-specific REDD+ intervention in Pemba, Zanzibar (Tanzania), we examine the circumstances under which REDD+ has a chance of success, teasing out specific features of both REDD+ interventions and the socio-economic and institutional contexts that render REDD+ a potentially valuable complement to community forestry. Additionally, we highlight some unanticipated positive outcomes associated with the design features of REDD+ projects. Our broader goal is to move away from ideologically-driven debate to empirically-based identification of general conditions where REDD+ could work, and to provide policy recommendations.

The coconut crab Birgus latro, the largest terrestrial decapod, is under threat in most parts of its geographical range. Its life cycle involves two biomes (restricted terrestrial habitats near the coast, and salt water currents of the tropical Indian and Pacific Oceans). Its dependence on coastal habitat means it is highly vulnerable to the habitat destruction that typically accompanies human population expansion along coastlines. Additionally, it has a slow reproductive rate and can reach large adult body sizes that, together with its slow movement when on land, make it highly susceptible to overharvesting. We studied the distribution and population changes of coconut crabs at 15 island sites in coastal Tanzania on the western edge of the species' geographical range. Our aim was to provide the data required for reassessment of the extinction risk status of this species, which, despite indications of sharp declines in many places, is currently categorized on the IUCN Red List as Data Deficient. Pemba Island, Zanzibar, in Tanzania, is an important refuge for B. latro but subpopulations are fragmented and exploited by children and fishers. We discovered that larger subpopulations are found in the presence of crops and farther away from people, whereas the largest adult coconut crabs are found on more remote island reserves and where crabs are not exploited. Remoteness and protection still offer hope for this species but there are also opportunities for protection through local communities capitalizing on tourist revenue, a conservation solution that could be applied more generally across the species' range.

African lions are a significant threat to pastoralists, triggering both retaliatory and nonretaliatory killings that represent a high-profile example of human-wildlife conflict. In the present article, we report on a grassroots campaign to reduce such conflict by shifting agropastoralists' attitudes toward lion killing and the central role of bylaws in its apparent success. Insofar as all of East Africa's principal protected areas still harboring lions are surrounded by pastoralist populations, the vast majority of which persecute lions, this novel strategy is of considerable wide-scale and practical significance. We report on an estimated 59%-69% reduction in the number of lions killed since the implementation of bylaws and use our experiences to highlight the need for fresh dialog among project managers, conservation organizations, and their funders in crafting appropriate conservation success metrics. In the context of human-wildlife conflict, changes in peoples' norms and attitudes are of greater significance over the long term than simplistic tabulations of the number of individuals saved.

Internal or within-state migration is common in Africa and elsewhere and has environmental and social consequences that are often poorly understood. We conducted a national-scale study tracking the movements of agropastoralists in Tanzania and documented the extent of associated environmental changes. The data were drawn from interviews with government officials in 80 rural districts covering the majority of land area across the country. According to interviewees, recent settlement is associated with forest clearing, overgrazing, and landscape burning. Conflicts such as lion killing and forced evictions of settlers often occur. Our interview data uncover limited capacity and lack of coordination among different levels of government to deal with these challenges. The novelty of our study is in its ability to draw on reports from ground-level administrators and to aggregate this information in order to both describe the impacts of rural migration over a large area and inform appropriate policy action from national-level decision-makers.

Fewer than 40,000 lions are left in Africa, perhaps 40% of which reside in Tanzania. Lions in East Africa are commonly killed in situations where they prey on livestock, either to retaliate for loss or avert future attacks. Among the Sukuma, Tanzania's largest cattle-raising ethnic group, tradition allows a lion killer to visit households, perform a special dance, and demand rewards for ridding the area of a potentially dangerous predator. Here we document how this tradition of gift-giving provides sufficient economic incentive that lion killing continues to persist in the face of a near absence of livestock loss from lions. Contemporary lion killers no longer act as avengers, retaliating for loss or averting future attacks, but as hunters, pursuing non-threatening lions far from residential and grazing areas and often inside protected areas. Our study reveals that Sukuma householders are less likely to reward a lion dancer if they have received frequent visits from dancers (indicative of donor fatigue) and if they perceive change in motivation from avenging to hunting. These findings suggest that it may be possible to reduce illegal killing of lions by working through Sukuma institutions responsible for collective action within the local community, and to remove the economic incentive for killing non-problem lions. © 2014.

Otherwise, apparently cryptic mammals often have conspicuous patches of colour on distal regions of their body, possibly for signalling. To investigate ideas about communication within sociosexual contexts, we used a comparative dataset for 2726 terrestrial mammals to match the coloration and patterning of distal body areas (head, chest, rump and tail) to activity cycle, group size, sexual size dimorphism, mating system and congener overlap at both Class and Order levels. Using phylogenetic controls, we uncovered repeated associations between white colour patches and nocturnality, conspicuous rump patches and sexual selection and multicoloured, complex patterning on distal regions of the body being associated with small group size. Overall, however, we found rather few associations between conspicuous coloration and behavioural, social and morphological variables, suggesting that visual signalling is not a key driver of communication in mammals, perhaps because the majority are nocturnal and solitary, and rely on olfactory signalling. [ABSTRACT FROM AUTHOR]

Widely dispersed fragmented populations are a challenge to monitor because subpopulation sizes may be very small, difficult to access and time consuming to sample regularly. We use the coconut crab (Birgus latro) on Pemba, United Republic of Zanzibar as a case study for estimating highly fragmented populations and metapopulation sizes. The species is a very large terrestrial decapod threatened by exploitation and habitat alteration and now classified as vulnerable. We developed an integrated model to analyse capture‐mark‐recapture (CMR) data from five sites jointly with count data from 24 sites to estimate site‐level densities and population sizes, predicted total population size across the Pemba archipelago, and investigated the effect of six predictors of human influence on density. We fitted separate models to test the effect of the same predictors on raw counts and individual body mass. We estimate the total population of coconut crabs on the Pemba archipelago to be c. 6700 terrestrial individuals. We show that government protection generally affects crabs positively, whereas presence of agriculture negatively affects their densities. This study highlights that time‐consuming CMR data can be leveraged to estimate densities on less visited sites, and that fully protected islands are critical for maintaining relatively high population densities. Our overall population estimate suggests that Pemba still hosts a viable coconut crab population in a part of its range where the species is otherwise in steep decline. [ABSTRACT FROM AUTHOR]

To examine factors that might influence how people subscribe to different reasons for conserving biological diversity, we modified Ehrenfeld's [American Scientist 64 (1976) 660] classic reasons for conserving species and habitats into consumption, tourism, medicine, science. education, environmental baselines, ecosystem services, intrinsic value, and added another, human cultural heritage. We then explored the opinions of undergraduates enrolled in a classic conservation biology course, or a people and conservation course, about these nine arguments, using a 27-statement questionnaire. By matching responses made before and after each course, we found that students, in general. became more committed to using most of Ehrenfeld's arguments but that this was highly contingent on which conservation course that they had taken. None became committed to the argument that linked wildlife conservation to human culture. however. Course and grade that students attained influenced the extent to which students were sympathetic to different arguments but gender had no effect. These findings show that the type of conservation knowledge imparted to students makes them differentially sympathetic to many of the arguments used to advocate wildlife conservation. (C) 2003 Elsevier Ltd. All rights reserved.