Species richness has classically been thought to increase from the poles towards the Equator, and from high elevations down to sea-level. However, the largest radiation of butterflies in Madagascar, the subtribe Mycalesina (c. 67 spp.) does not exhibit such a monotonic pattern, either for empirical records or for interpolated species ranges. Instead, summation of mycalesine ranges generates a domed curve of species richness values approximately symmetric around mid latitudes within the island, a pattern most smoothly exhibited by the wider ranging and better known species, and a less symmetric curve peaking near mid elevations. Hotspots for the summation of 1 183 species ranges and seven out of the ten groups of insects and vertebrates analysed (butterflies, cicindelid and enariine melonthid beetles, ctenuchiine moths, chameleons, frogs, birds, lemurs, tenrecs, and rodents) also occur at both mid latitudes and elevations. The most strongly parabolic pattern is shown by animals (637 spp.) whose ranges are confined to the highly linear rainforest biome. This rainforest species richness curve is resilient in shape even after controlling for particular effects of area and irregular sample effort. In sharp contrast, at least eight different environmental parameters for the rainforest biome tend to increase monotonically towards the northern, more tropical, boundary, a trend evident only in species richness gradients of more narrow-ranging species. The one-dimensional latitudinal species richness curves and hotspots observed in fact best reflect overall the geometric predictions of a null model for ranked range size partitions of the regional species pool . This analytical model is based on the uniform probability distribution. and assumes that species ranges are constrained by the position of biome or island boundaries . The same logarithmic equations applied iteratively to longitude also accurately predict hotspots for more realistic species ranges containing gaps. as shown for two-dimensional species richness patterns for the Madagascan rainforest dataset . Biogeographic and conservation implications of the bounded range overlap concept are discussed . 0 I999 The Linnean Society of London ADDITIONAL KEYWORDS:-quantitative biogeographymacroecologylatitudinal and elevational gradientsgeometric range boundary constraintshumped or parabolic diversity curve . hotspot . range size frequency distribution . indicator group .

Human-nature interactions shape biodiversity and natural resources. Planning conservation and engaging stakeholders in dialogues about conservation require an understanding of indirect threats arising from socioeconomic and political conditions, plus participatory methods to build consensus for action. We present a method for spatial assessment of threats, which involves stakeholders in decision-making and planning for conservation. We developed and tested the method in wildlife conservation projects in Asia, Africa, Madagascar, and Central America. The method follows a fivestep process: each participant lists the human activities that are the most damaging to biodiversity and natural resources in their region (direct threats) and the role that users, managers, and policymakers play to promote or facilitate these activities (indirect threats); all participants vote to rank the worst direct threats and to map the locations of these threats at their site. The output maps are amenable to use in GIS analysis. We show how these maps help to plan, monitor, and implement interventions in wildlife conservation projects.

Grâce à l'expédition Radeau des Cimes 2001, de nombreuses espèces de Lépidoptères peuvent être rajoutées aux inventaires faunistiques de la presqu'île de Masoala, encore très incomplets. Des papillons et quelques chenilles ont été collectés pendant cinq semai¬ nes (principalement en novembre) dans la région de Tampolo, mais aussi dans celle d'Andranobe, au sud d'Ambanizana. Un certain nombre de chenilles ont été élevées avec suc¬ cès, notamment celle d'une noctuelle, apparemment non décrite (Herminiinae) et la chenille jusque-là inconnue du Sphingidae Rhagastis lambertoni (Clark). A partir de nids d'un Hypsoides sp. (Notodontidae Thaumetopoeinae ; espèce peut-être nouvelle), divers insectes ont été obte¬ nus, dont un Cosmopterigidae et un Phycitinae (Pyralidae) vraisemblablement des espèces nou¬ velles pour la science. Au moins 23 espèces de Bombycoïdes (dont le Sphingidae Hippotion melichari Haxaire) ont pu être capturées-en octobre-novembre 2001-dans la région de Tampolo. En comparant l'efficacité de trois pièges lumineux similaires, mais installés, l'un sur le Radeau des Cimes, les deux autres sous celui-ci, dans le sous-bois, on peut avancer l'hypo¬ thèse selon laquelle la plupart des Sphinx nocturnes tendraient à voler au-dessus de la canopée. Une première liste des Sphingidae de Masoala est proposée. Parmi les Rhopalocères, 65 espèces de Rhopalocères ont été distinctement aperçues (p. ex. Smerina manoro (Ward)-Nymphalidae) ou capturées. Trois Hesperiidae sont signalés pour la première fois de Masoala : Perrotia how a (Mabille), P. silvestralis (Viette) et Borbo ratek (Boisduval). Mots-clés.-Lépidoptères, premiers états, Sphingidae. Radeau des Cimes. Masoala. Accepté pour publication le 15 mars 2007. The Canopy Raft in the Masoala National Park (Madagascar). 1.-Towards a Lepidoptera survey Summary.-Thanks to the 2001 "Canopy Raft" expedition, many new records can be con¬ sidered for the Lepidoptera fauna of the Masoala Peninsula, a still poorly investigated region of Madagascar. Moths, butterflies and a few caterpillars were collected over a five week period (mainly in November) in the area of Tampolo, but also near Andranobe, south of Ambanizana. A number of caterpillars have been bred successfully, in particular that of an apparently new herminiine species (Noctuidae) and the previously unknown larva of Rhagastis lambertoni (Clark) (Sphingidae). Several insect species were obtained from the nests of a possibly new species of Hypsoides (Notodontidae: Thaumetopoeinae). Among them are a Cosmopterigidae and a phycitine Pyralidae, both of which are likely to represent new species. At least 23 species of Bombycoidea (e.g. Hippotion melichari Haxaire-Sphingidae) were caught in october-november 2001 in the Tampolo area. Through a comparison between the efficiency of a light trap put on the canopy raft and that of two similar ones placed under the raft, in rainforest undergrowth, it would seem that most nocturnal hawk-moths tend to fly above canopy level. A checklist of the Sphingidae of Masoala can be proposed for...