Oryx Vol 41 No 2 April 2007 Identification of priority areas for plant conservation in Madagascar using Red List criteria: rare and threatened Pandanaceae indicate sites in need of protection Martin W. Callmander, George E. Schatz, Porter P. Lowry II, Michel O. Laivao, Jeannie Raharimampionona, Sylvie Andriambololonera, Tantely Raminosoa and Trisha K. Consiglio Abstract A major problem in establishing effective cell sizes to estimate area of occupancy. Using a grid cell protocols for conserving Madagascar’s biodiversity is size within the range suggested by IUCN overestimates the lack of reliable information for the identification of threatened status if based solely upon specimen data. priority sites in need of protection. Analyses of field data For poorly inventoried countries such as Madagascar and information from herbarium collections for mem- measures of range size based on such data should be bers of the plant family Pandanaceae (85 spp. of complemented with field observations to determine Pandanus; 6 spp. of Martellidendron) showed how risk population size, sensitivity to disturbance, and specific of extinction assessments can inform conservation threats to habitat and therefore potential population planning. Application of IUCN Red List categories and decline. The analysis of such data can make an criteria showed that 91% of the species are threatened. important contribution to the conservation planning Mapping occurrence revealed centres of richness and process by identifying threatened species and revealing rarity as well as gaps in Madagascar’s existing protected the highest priority sites for their conservation. area network. Protection of 10 additional sites would be required to encompass the 19 species currently lacking Keywords IUCN Red List, Madagascar, Pandanaceae, representation in the reserve network, within which east protected areas, threatened species. coast littoral forests are particularly under represented and important. The effect of scale on assessments of risk This paper contains supplementary material that can of extinction was explored by applying different grid only be found online at http://journals.cambridge.org Introduction for conservation and for the study of evolutionary processes (Myers & Knoll, 2001). The Malagasy flora is characterized by high levels of At the 2003 World Parks Congress in Durban, South diversity (12,000–14,000 species; Goodman & Benstead, Africa, the Malagasy President, Marc Ravalomanana, 2005; Phillipson et al., 2006) and endemism (.90%; announced plans to triple the size of the protected areas Schatz, 2001), and is threatened by unsustainable land network by 2008, from 1.7 to 6 million ha (nearly 10% of use practices, such as shifting cultivation and fire, that the country). This goal has been integrated into Phase 3 have left ,10% of the original vegetation intact (Myers of the National Environmental Action Plan, and an et al., 2000). Madagascar is regarded as a high priority initial set of target areas has been identified for inclusion in an expanded protected area network. However, research and analysis is needed to ensure maximal Martin W. Callmander (Corresponding author) Missouri Botanical Garden, P.O. Box 299, St. Louis, MO 63166-0299, USA, and University of Neuchaˆtel, inclusion of the country’s biodiversity. Application of Laboratoire de Botanique Evolutive, Case Postale 158, 2009 Neuchaˆtel, the IUCN Red List criteria, a widely recognized tool for Switzerland. E-mail [email protected] identifying threatened species, offers a powerful method George E. Schatz, Porter P. Lowry II* and Trisha K. Consiglio Missouri to identify priority sites for protection by providing Botanical Garden, P.O. Box 299 St. Louis, MO 63166-0299, USA. information on the conservation status of species in the Michel O. Laivao, Jeannie Raharimampionona, Sylvie Andriambololonera wild (Rodrigues et al., 2006). In Madagascar, however, and Tantely Raminosoa Madagascar Research and Conservation Program, only 425 plant species have been assessed to date, of Missouri Botanical Garden, BP 3391 Antananarivo 101, Madagascar. which only 210 were evaluated using the current criteria *Also at: De´partement Syste´matique et Evolution, Muse´um National d’Histoire (IUCN, 2006). Many of the species that have not been Naturelle, Case Postale 39, 57 rue Cuvier, 75231 Paris CEDEX 05, France. assessed are so poorly known or rare that up-to-date Received 4 October 2005. Revision requested 24 April 2006. distribution information is unavailable. To address this Accepted 13 February 2007. we have developed an efficient, robust procedure for 168 ß 2007 FFI, Oryx, 41(2), 168–176 doi:10.1017/S0030605307001731 Printed in the United Kingdom Downloaded from https://www.cambridge.org/core. IP address: 170.106.39.241, on 04 Oct 2021 at 16:50:22, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605307001731 Malagasy Pandanaceae 169 evaluating restricted range plant species using primary underestimating the number of threatened species; this occurrence data from herbarium collections and recent approach has been followed here. We used the four Red field observations ( Schatz, 2002; Raharimampionona et al., List criteria and subcriteria (IUCN, 2001) to determine 2006). This procedure also identifies sites with high threat: rapid population decline (Criterion A), limited species richness and concentrations of rare species that geographic range and small population size linked with constitute prospective conservation priorities. Here we fragmentation, decline or fluctuation (Criteria B and C), provide an example of the application of these comple- and very small population size (Criterion D); we did not mentary approaches using the plant family Pandanaceae. attempt to analyse extinction risk quantitatively using Pandanaceae comprise four genera of arborescent or Criterion E. lianoid dioecious monocotyledons, two of which occur For each species of Pandanaceae the geographical in Madagascar, Martellidendron (7 spp., all but one information system Arcview v. 3.3 (ESRI, Redlands, USA) restricted to the island) and the widespread was used to measure three parameters required for Paleotropical genus Pandanus (c. 600 spp., with 85 spp. categorization using the Red List criteria (IUCN, 2001): endemic to Madagascar). The taxonomy of both genera extent of occurrence (EOO, minimum convex polygon has been revised recently (Laivao et al., 2000, 2006; containing all points of occurrence), area of occupancy Callmander et al., 2001, 2003a,b,c; Callmander & Laivao, (AOO, area estimated by superimposing a grid onto 2002) and, combined with information from recent field occurrence points and calculating the cumulative area of work, provides data suitable for illustrating our proce- cells occupied by a species), and predicted future dures for identifying conservation priorities. Species of decline (PFD, estimated continuing reduction in a Pandanaceae grow in all tropical forest types (dry to species’ AOO). For species restricted to primary vegeta- humid) and exhibit both widespread and restricted tion PFD was estimated using (AOO outside protected distributions. By applying IUCN Red List categories, areas / total AOO) * 100, which is based on two calculating richness and rarity, and identifying areas assumptions that reasonably reflect the current situation with high diversity of endemic Malagasy Pandanaceae, for long-lived arborescent plants in Madagascar (Schatz we (1) illustrate how assessments using herbarium data et al., 2000; Good et al., 2006): within a few decades (3 can inform conservation planning, (2) show how the generations for most Pandanaceae, estimated to be 30–50 assessments can be used to evaluate the effectiveness of years, depending on the species) ongoing habitat the existing protected area network and identify high degradation and destruction will leave few significant priority sites for establishing new protected areas and/ areas of primary vegetation outside the protected area or implementing alternative conservation strategies, (3) network, and loss of primary vegetation within pro- explore difficulties encountered in applying the Red List tected areas will be minimal. While some unprotected criteria relating to species distributions, and (4) illustrate areas may escape destruction (especially on steep or some problems involved in using herbarium collections rugged terrain), it is nevertheless unlikely that many and field observations for Red List assessments and populations of long-lived plants will survive outside show how occurrence data can be analysed most protected areas after 3 generations, given Madagascar’s effectively to provide useful interpretations for conser- high rate of deforestation (Green & Sussman, 1990; vation. Achard et al., 2002). For species tolerant of habitat disturbance the calculation of PFD using this method would produce an overestimate of population reduction, Methods and therefore we have evaluated such species based on Geographic data were compiled from .550 herbarium direct field observations, indicating those known to be in specimens representing the 91 endemic species of continuing decline (without attempting to calculate PFD) Malagasy Pandanaceae currently recognized (Fig. 1). so that the other Red List criteria can be applied. Geographical coordinates for recent collections were The number of subpopulations within the total recorded with a global positioning system or assigned population