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We have begun an intensive series of investigations into the environmental and endocrine mechanisms regulating cooperative breeding in a semi‐arid tropical environment. A colour‐marked population of white‐browed sparrow weavers (Plocepasser mahali) was studied at a field site near Nyamaluma Camp, Luangwa Valley, Zambia (13dG S). This species breeds from October to April, although some clutches may be found as early as August and young may be fed until May. Non‐disruptive techniques were employed to monitor annual cycles of gonadal development, body mass and fat reserves, and small blood samples were collected to measure circulating levels of reproductive hormones and corticosterone. All individuals were released after sampling and the social and reproductive activities recorded by systematic behavioural observations. Each individual could thus be identified as: (1) a breeding adult; (2) a related helper (i.e. offspring of the breeding male and female within the group); or (3) a non‐related (=invader) helper (these birds helped defend territory but did not help feed young; they were not related to the breeding pair and usually originated from outside the group). Breeding males had larger testes and higher levels of testosterone than either related helpers or invader helpers. In females, all status groups had follicles up to 2 mm in diameter, but only breeding females ovulated. There were no differences in plasma levels of reproductive hormones among different status females, except for higher circulating luteinizing hormone (LH) in invader female helpers during the first part of the breeding season. Although plasma levels of testosterone were highest in breeding males, the maximum titres were two orders of magnitude less than in males of passerine species from temperate regions. Furthermore, injections of a peptide hormone GnRH (gonadotropin‐releasing hormone) increased plasma LH levels in both males and females, and were followed by rises in testosterone levels only in males, but not over the normal maximum seen in February. GnRH‐induced high levels of LH did not affect testosterone concentrations in the blood of females. Results obtained thus far indicate that the hormonal control of aggression in white‐browed sparrow weavers is different from that predicted by investigations on north temperate species. Whether these phenomena are typical of tropical species, particularly cooperative breeders, remains to be determined. Since most of the world's species of birds live in the tropics, and a substantial fraction of them breed cooperatively, more investigations are needed to establish the hormonal basis of reproductive behaviour and cooperative breeding. Given the baseline data already collected, the white‐browed sparrow weaver will be a useful model.

Managing an area as a national park in Africa often entails dealing with human pressures from regions surrounding the protected area Dealing with these human pressures is the subject of this paper, which goes well beyond mere law enforcement to discuss the realm of traditional leadership in the village, rural socioeconomics, and the services of wildlife management by government in areas surrounding a national park. This paper describes the results of an experimental project in Zambia that sought to halt the drastic loss of elephants and rhinos to poaching in and around protected areas in the Luangwa Valley. The design of this project was to involve local residents outside national parks in wildlife protection and management activities. In addition, sustained‐yield uses of wildlife were adopted to recycle revenue shares into community development and to make the program of wildlife management financially self‐supporting. To help carry out the various tasks of protecting and developing wildlife resources, residents were trained and employed as wildlife management staff Village wildlife councils provided advice and assistance. Safari concessions yielded sufficient revenue to meet the recurrent costs of wildlife management and also generated significant earnings for local community benefits. As a result; poaching dropped dramatically, local economies were improve and village attitudes toward wildlife management and conservation became more positive.

In the Luangwa Valley, Zambia, persistent poverty and hunger present linked challenges to rural development and biodiversity conservation. Both household coping strategies and larger-scale economic development efforts have caused severe natural resource degradation that limits future economic opportunities and endangers ecosystem services. A model based on a business infrastructure has been developed to promote and maintain sustainable agricultural and natural resource management practices, leading to direct and indirect conservation outcomes. The Community Markets for Conservation (COMACO) model operates primarily with communities surrounding national parks, strengthening conservation benefits produced by these protected areas. COMACO first identifies the least food-secure households and trains them in sustainable agricultural practices that minimize threats to natural resources while meeting household needs. In addition, COMACO identifies people responsible for severe natural resource depletion and trains them to generate alternative income sources. In an effort to maintain compliance with these practices, COMACO provides extension support and access to high-value markets that would otherwise be inaccessible to participants. Because the model is continually evolving via adaptive management, success or failure of the model as a whole is difficult to quantify at this early stage. We therefore test specific hypotheses and present data documenting the stabilization of previously declining wildlife populations; the meeting of thresholds of productivity that give COMACO access to stable, high-value markets and progress toward economic self-sufficiency; and the adoption of sustainable agricultural practices by participants and other community members. Together, these findings describe a unique, business-oriented model for poverty alleviation, food production, and biodiversity conservation.conservation farming | food security | poaching | carbon | sustainability T he Luangwa Valley exhibits many characteristic linkages between poverty traps and risks to biodiversity. There is heavy reliance of households (HHs) on limited natural resources, shared vulnerability to yearly climatic variability, an absence of strong social/economic institutions, and unintended negative consequences of economic development efforts. The situation has been heading toward a new equilibrium impoverished in both human condition and biodiversity. Positive feedback stemming from trophic disruptions to wildlife populations and habitat, relatively recent shocks such as HIV/AIDS or fluctuations in cotton markets, and the continual shock of variations in rainfall all serve to hasten this change. Given the severity of these interrelated problems, a unique approach has been implemented to preserve biodiversity by focusing on improving livelihoods and food security. The Community Markets for Conservation (COMACO) model uses markets and an adaptive business approach to promote sustainable agricultural practices, rather than base development on natural re...

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