using four heat-flux plates and four temperature probes. Evapotranspiration and CO 2 flux were measured using the eddy-covariance method with an Applied Technologies sonic anemometer and LI-COR 6262 infrared gas analyser mounted on 2-m towers 25 . The mean and standard error for energy flux, gross primary production and evapotranspiration at sites 3 and 4 were calculated on the basis of 30-min averages. CO 2 fluxes at sites 11, 17 and 21 were determined using eddycovariance methods and 2.5-m towers 26 . Mean values and standard errors at these sites were calculated using the daily mean CO 2 fluxes. The daily methane fluxes were integrated over the thaw period to obtain annual emission. Winter methane fluxes were assumed to be zero. CH 4 flux was measured during the thaw season, Jun-Aug, at 27 MNT and MAT sites along the Dalton Highway in 1996 using a static chamber method 30 . Air samples were taken over periods of 30-45 min and were analysed on a gas chromatograph equipped with a flame ionization detector.

Uganda is one of the most biologically diverse countries in Africa, with much of its biodiversity represented in a system of 10 national parks, 10 wildlife reserves, and 710 forest reserves, covering 33,000 km2 (14%) of the country's area. We focus on the role of the forest reserves in biodiversity conservation and describe a procedure we developed to design a national system of forest nature reserves. In the late 1980s a policy was instituted to dedicate half the area of forest reserves to sustainable timber production and the other half to environmental protection (with 20% as nature reserves). To select suitable sites, a 5‐year, US$1‐million program of biodiversity and resource assessment was undertaken, focusing on five biological indicator species groups and covering all the major forest reserves. Based on data generated by the field studies, we ranked each forest in terms of various criteria—(species richness, rarity, value for nonconsumptive uses, timber production, and importance to local communities)—and used an iterative site selection procedure to choose the most suitable combination of forests for nature reserve establishment. Our procedure maximized complementarity in representing species and habitats in reserves across the whole protected‐area system. We initially selected sites using purely biological criteria but later modified our procedure to ensure that opportunity costs and potential land‐use conflicts were minimized. Our preferred network of sites included 14 forests that, in combination with the existing national parks, would account for 96% of species represented in the country's protected areas. These 14 forests were classified as “prime” and “core” sites and were selected for the establishment of large nature reserves (averaging 100 km2). The addition of 25 smaller “secondary” forest nature reserves (averaging 32 km2) would protect more than 99% of the indicator species.

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With less than 3200 wild tigers in 2010, the heads of 13 tiger-range countries committed to doubling the global population of wild tigers by 2022. This goal represents the highest level of ambition and commitment required to turn the tide for tigers in the wild. Yet, ensuring efficient and targeted implementation of conservation actions alongside systematic monitoring of progress towards this goal requires that we set site-specific recovery targets and timelines that are ecologically realistic. In this study, we assess the recovery potential of 18 sites identified under WWF’s Tigers Alive Initiative. We delineated recovery systems comprising a source, recovery site, and support region, which need to be managed synergistically to meet these targets. By using the best available data on tiger and prey numbers, and adapting existing species recovery frameworks, we show that these sites, which currently support 165 (118–277) tigers, have the potential to harbour 585 (454–739) individuals. This would constitute a 15% increase in the global population and represent over a three-fold increase within these specific sites, on an average. However, it may not be realistic to achieve this target by 2022, since tiger recovery in 15 of these 18 sites is contingent on the initial recovery of prey populations, which is a slow process. We conclude that while sustained conservation efforts can yield significant recoveries, it is critical that we commit our resources to achieving the biologically realistic targets for these sites even if the timelines are extended.

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