The population status of chameleons within Ranomafana National Park, Madagascar, and recommendations for future monitoring Richard K. B. Jenkins, Lee D. Brady, Kieron Huston, Juliet L. D. Kauffmann, Jeanneney Rabearivony, Georges Raveloson and J. Marcus Rowcliffe Abstract Malagasy chameleons are threatened by the on distance sampling within an area of relatively relentless pace of habitat destruction. Their great popu- undisturbed rain forest at Ranomafana National larity amongst herpetoculturalists has also resulted in Park. In total 394 individuals from six species were collection for international animal markets. Most previ- recorded and population densities (+ SE) of 27.2 + ous fieldwork has focused on the compilation 5.4/ha Brookesia spp. and 21.4±4.0/ha Calumma of much needed species inventories, but little attention spp. were estimated using the computer program has been given to estimating chameleon popu- DISTANCE. The authors propose that monitoring of lation densities. This lack of information prevents a chameleons in areas subject to different threats should reliable assessment of the effects of habitat loss and begin immediately using the methods outlined in this direct exploitation on wild populations. A simple and paper. repeatable methodology for the monitoring of chameleon populations is therefore urgently required. Keywords Chameleon, Madagascar, population den- The present study developed survey techniques based sity, rain forest, trade. Introduction increased significantly and for some chameleon species increases of up to 400 per cent have been reported Although the degradation and destruction of forests are (World Conservation Monitoring Centre & IUCN/SSC undoubtedly the primary threat to Madagascar's fauna Trade Specialist Group, 1991; IUCN/SSC Trade Special- (Raxworthy, 1988), the additional pressure of exploi- ist Group et al, 1993). These figures probably underesti- tation for international animal markets cannot be re- mate the true number of individuals exported because garded as insignificant (IUCN/SSC Trade Specialist mortality during transit is often undocumented (IUCN/ Group et al, 1993). Of all Madagascar's wildlife it is the SSC Trade Specialist Group et al., 1993) and illegal herpetofauna that is perhaps the most threatened by exportation levels are difficult to quantify. Also, be- such collection (Behra, 1993; IUCN/SSC Trade Specialist cause chameleons require specialized husbandry Group et al, 1993). Since the mid-1980s both the diver- (Bustard, 1989; de Vosjoli, 1990) captive breeding is sity and quantity of Malagasy reptiles in the trade have unlikely to provide a sufficient supply of animals to meet increasing demands. Richard K. B. Jenkins School of Pure and Applied Biology, University of Wales, PO Box 915, Cardiff, CF1 3TL, UK. The current trade Lee D. Brady (corresponding author), The Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, Kent, CT2 In a review by the International Union for Conservation 7NJ, UK. E-mail: [email protected] of Nature (IUCN) Trade Specialist Group, endemic Kieron Huston Surrey Wildlife Trust, Pirbright, Surrey, UK. Malagasy reptiles formed approximately 8 per cent of the species on Convention on International Trade in Juliet L. D. Kauffmann Department of Biology, The Open University, Milton Keynes, UK. Endangered Species (CITES) Appendix II that were traded at levels likely to be a threat to wild populations Jeanneney Rabearivony and Georges Raveloson Universite d'Antananarivo, Madagascar. (World Conservation Monitoring Centre & IUCN/SSC Trade Specialist Group, 1991). The report concluded J. Marcus Rowcliffe Institute of Zoology, Zoological Society of that by 1991 trade had increased for both CITES-listed London, London, UK. and non-listed species to a level that may be detrimen- Received 31 October 1997. Accepted 24 July 1998 tal to wild populations. Some of the species recorded in 38 1999 FFI, Oryx, 33(1), 38-46 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.14, on 25 Sep 2021 at 15:33:17, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1046/j.1365-3008.1999.00034.x The population status of chameleons within Ranomafana National Park, Madagascar 39 consignments to Europe, Japan and North America 1988; Raxworthy & Nussbaum, 1994) and have re- were considered too rare for collection, being often sulted in detailed information on geographical and known to science from a single museum specimen altitudinal range (Raxworthy & Nussbaum, 1995). (e.g. Furcifer belalandaensis Brygoo & Domergue 1968 While evidence highlighting the need for more exten- listed in IUCN/SSC Trade Specialist Group et al, sive species inventories is provided by the continued 1993). Of most concern was the finding that all descriptions of new chameleon species (e.g. Bohme, chameleon species recorded in the trade were poorly 1997), it is clear that before export quotas can be set known in terms of population ecology, population at sustainable levels and directed at appropriate species, density and other important biological parameters. there needs to be more fieldwork to help define the For example, the impact of the trade in wild popu- range of chameleon population densities, followed by lations was 'unknown' for all 23 Brookesia species. Of long-term monitoring at key sites. Although reptile the 34 Calumma and Furcifer (both formerly Chamaeleo search techniques have been developed and refined in and still referred to as such by CITES) species, the recent years (Raxworthy, 1988; Raxworthy & Nuss- significance of trade was 'unknown, but believed to baum, 1994), there has been no attempt to publish be insignificant' for 47 per cent of the species, while even preliminary estimates of Malagasy chameleon 41 per cent were too poorly known for an appraisal population densities. to be made (IUCN/SSC Trade Specialist Group et al, 1993). In 1995 the CITES Standing Committee recom- mended that from 1996 all CITIES Parties suspend Surveying for chameleons imports of chameleons from Madagascar belonging to Distance sampling (fully described by Buckland et al, the genus Chamaeleo, with the exception of C. lateralis, 1993) is becoming increasingly popular with biologists C. oustaleti, C. pardalis and C. verrucosus (CITES Secre- for estimating population densities (e.g. Heydon & tariat, 1995). Although these four species are widely Bulloh, 1996). It provides an estimation of density by distributed (Glaw & Vences, 1994) and were not con- the calculation of a detection curve. This detection sidered to be threatened by past levels of trade curve is based on a series of perpendicular distances (IUCN/SSC Trade Specialist Group et al, 1993), no measured from a transect line or point to the object data on local population densities or the impact of of interest. The four main assumptions of this method collection on wild populations have ever been pub- are (after Buckland et al, 1993; Lancia et al, 1996): lished. 1. transect lines or points are placed at random in relation to the objects' distribution; Sustainable harvesting of chameleons 2. all objects at zero distance from the transect line or point are detected; While trade in poorly known and rare species is a 3. objects are detected at their initial location, before potential threat to their conservation, the abundance any movement occurs as a result of disturbance of some species may allow a level of collection that from the observer; will not harm wild populations. It has been argued 4. perpendicular distances can be measured accurately. that sustainable harvesting has potential benefits for both rural communities and species conservation (e.g. Allen & Edwards, 1995). Local collectors given a fair Chameleons are most readily found at their nocturnal price for reptiles may value protected areas for the roost sites (Parcher, 1974; Raxworthy, 1988), where they long-term revenue derived from collecting certain become pale and immobile. Low-roosting individuals species at agreed quota levels. Increased trade in are therefore relatively easy to find using torch light some widespread and common species may also com- (assumption 2) and do not move upon detection (as- pensate for the ban on trade in rarer species. How- sumption 3). Also, as long as roosting individuals are ever, for even the most common and widespread approached carefully, accurate measurements of per- chameleons to be sustainably harvested, enough basic pendicular distances are possible (assumption 4). information on their ecology must exist to ensure a The aim of the present study was to develop simple non-detrimental impact on the species at the local and repeatable line transect survey techniques based on population level. distance sampling methodologies. Survey work was Previous chameleon studies in Madagascar have then undertaken in order to determine the population concentrated on the compilation of species inventories status of chameleons within an area of undisturbed rain across a wide range of important sites (Raxworthy, forest at Ranomafana National Park. ' 1999 FFI, Oryx, 33(1), 38-46 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.14, on 25 Sep 2021 at 15:33:17, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1046/j.1365-3008.1999.00034.x 40 R. K. B. Jenkins ef al. N A To Antananarivo River' . Namorona To Mananjaiy / To Fianarantsoa 21°20"S 5 km Fig. 1 Map illustrating location of study 47°30"E site within Ranomafana National Park. Materials and methods and narrow ridge tops. The extensive forest trail system that exists within Ranomafana National Park is regu- Study area larly used for the monitoring of several taxonomic groups as part of an ongoing biodiversity monitoring Ranomafana National Park (21°17'S, 47°25'E; Fig. 1) is project (P. Wright, pers. comm.). Although herpetologi- situated between 800 and 1200 m above sea level, with cal surveys have been undertaken within the national a mean daily temperature ranging from 3 to 35 °C. park (e.g.