MODELING OF SPECIES GEOGRAPHIC DISTRIBUTION FOR ASSESSING PRESENT NEEDS FOR THE ECOLOGICAL NETWORKS T. Dokoa, *,F A. Kooimanb, A.G.Toxopeusb aGraduate School of Media and Governance, Keio University, 302 Z-building of Keio University, 5322 Endoh, Fujisawa, Kanagawa, 252-8520, Japan - [email protected] bDepartment of Natural Resources, International Institute for Geo-information Science and Earth Observation (ITC), P. O. Box 6, Hengelosestraat 99, 7500 AA, Enschede, The Netherlands - [email protected], [email protected] KEY WORDS: Ecology, Environment, GIS, Modelling, Algorithms, Landscape, Method, Proposal ABSTRACT: In Japan, attention is currently focused on designing ecological networks for wildlife animals. However there is an obvious lack of the species spatial information. This study aims (a) to acquire the potential spatial distribution of Asiatic black bear and Japanese se- row to identify core areas, and (b) to propose a methodology for assessing needs for ecological networks. 1836 species’ point records and 14 potential predictors were prepared in a GIS environment, split into a train and a test dataset. Screening predictors by statisti- cal analysis, we modeled species geographic distribution by three algorithms: GARP, MaxEnt, and GLMs in Kanagawa and Shizu- oka Prefectures. Based on the most accurate maps, assessed by Kappa statistics, population was estimated based on population den- sity and area of habitat patch. For bear, MaxEnt performed best with the predictor variables: altitude, distance to paths and stone steps, distance to wide roads, and vegetation cover types. GARP failed to predict presence in Fuji. Its best GLM equation was log(p/(1-p))=(-1.486e+01)+(7.335e-04)*distance to paths and stone steps+(9.470e-03)*altitude. For serow’s distribution, GARP per- formed best with altitude, slope, distance to highways, distance to general roads, distance to paths and stone steps, distance to rivers, and NDVI. Its best GLM equation was log(p/(1-p))=-5.91785430+0.04024136*slope+0.26478759*square root of altitude. The esti- mated numbers of individuals for bear was 5~9 in Mt. Ashitaka, 51~102 in Fuji-Tanzawa, 160~320 in South Alps, 4~8 in Mt. Ke- nashi, 4~8 in Izu Peninsula, and 6~11 in Hakone; for serow, < 1581 were estimated in Fuji-Tanzawa, and < 537 in other areas. For bear MaxEnt and for serow GARP are the best algorithms, but GLM has good transferability. There is a need for ecological net- works in Fuji-Tanzawa for bear, but not for serow. 1. INTRODUCTION from interviews and questionnaires on a sampling grid of 5 by 5 km, these distribution maps were compiled at a national scale 1.1 Biodiversity loss and ecological networks (1: 2,500,000). The New Biodiversity Strategy of Japan (March 27, 2002) Although these maps provide insight in species’ distribution at stipulates seven major themes for implementing biodiversity a glance, they do not reflect distribution at local population conservation policies. The first theme is conservation of prior- level. An appropriate approach for preparing conservation and ity areas and formation of ecological networks. Its basis is to re- zoning plans requires spatially explicit information of species inforce the protected-area system. In addition to the perspective distribution at a local scale with more accurate resolution. With of conserving natural landscape of the Natural Parks, measures this information, the core area of a suitable habitat can be iden- from the perspective of ecosystem conservation, especially of tified, and ecological networks can be designed if necessary. animal habitat conservation, should be institutionalized. The There are several studies that have integrated habitat models development of the ecological networks can connect the frag- into GIS (for example, see Corsi et al., 1999). However, these mented habitats of wild animals, stem the biodiversity loss, and have not assessed the need for ecological networks of large promote dispersal and genetic exchange of wild species. Seri- mammals. Also, to date, no studies were found on quantitative ous fragmentation of habitats has been caused by the industri- needs assessment of ecological networks. alization of agriculture, restructuring of land use, the building of huge transport networks and metropolitan (Stanners and In this paper, we present a quantitative methodology for the Bourdeau, 1995). For fragmented habitats, the theory of island modeling of the geographic distribution of two key species of biogeography (MacArthur and Wilson, 2001) can be applied, large mammals in order to assess the need for ecological net- and connecting the ‘islands’ through the ecological networks works. can reduce the risk of extinction of species. 1.2 Research objectives As for the Japanese mammals, the Ministry of Environment of Japan has conducted the national distributional survey of Japa- There are three main objectives of this study: 1) to acquire nese animals (Biodiversity center of Japan, 2004) in 1978 and more accurate potential spatial distribution of habitats of ’key’ in 2003 as a monitoring activity. The main objective was to ac- wildlife species, 2) to identify the ‘core areas’ of these habitats, quire national distributional maps of ten main mammals, in- and 3) to assess the present needs for ecological networks. cluding key wildlife species in this study. Based on survey data * Corresponding author. 267 The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 At present, the most accurate distribution map of the target spe- established based on consideration of time, human and financial cies has a resolution of 2 by 2.5 km (Ohba, 2002). This study resources available for this study. aims to create distribution maps with a resolution of 90 by 90 m, or at best 30 by 30 m. The area of interest is the Fuji and Tan- Based on the criteria established above, the Asiatic black bear zawa regions located in the central part of Japan’s main island. and Japanese serow were identified as the target species among The administrative boundaries of Kanagawa Prefecture and the Japanese mammal species. Shizuoka Prefecture have been selected as the study area. The Asiatic black bear and the Japanese serow were identified as the In Japan, 19 local populations of the Asiatic black bear (Japan target species. Wildlife Research Center, 1992) and 40 local populations of Japanese serow (Japan Wildlife Research Center, 1985) are rec- ognized, of which three local populations are considered to ex- 2. METHODOLOGY ist for both species in our study area: Fuji, Tanzawa and South Alps. The mainstream of the current studies has focus on habi- 2.1 Study area tat and food analysis for both species (Deguchi et al., 2002; Hashimoto et al., 2003; Huygens et al., 2003), thus very little is The following criteria were used in order to select an appropri- known about the distribution within the sites. Yamaguchi et al. ate area for the study: (1998) compiled the point observations of Japanese serow in • Known fragmentation of habitats Tanzawa region. Ohba (2002) mapped serow’s distribution in a • Variation in landscapes sampling grid of 5 by 5 km in Shizuoka Prefecture based on • High biodiversity questionnaires. Mochizuki et al. (2005) mapped bear’s distri- • Presence of endemic species bution in sampling grid of 2 km by 2.5 km in Fuji local popula- tion based on point observation of field signs and mapped point The area of interest is the ‘Fuji region’, part of the Fuji- localities of four years of tracked movements of 14 individual Hakone-Izu National Park and the ‘Tanzawa region’, Japan. bears. To our knowledge, no study attempted to model these The Fuji-Hakone-Izu National Park covers an area of 121,851 species probabilities of occurrence by environmental predictors ha, located in four prefectures and consisting of Mt. Fuji (3776 in Japan. m), Hakone, Izu Peninsula and the Izu Island chain. In the park various types of volcanoes occur, as the park crosses the Fuji 2.2.2 Asiatic black bear volcanic belt from the Pacific Ocean to the central part of the The Asiatic black bear (Ursus thibetanus japonicus) inhabits Main Island. Vegetation varies from the warm-temperature the islands of Honshu and Shikoku in Japan. The Asiatic black vegetation zone on the Izu Island chain to the Alperstein zone bear is a threatened species - assessed as “vulnerable” - accord- of Mt. Fuji. The park contains diverse habitats for mammals ing to the IUCN Red List of Threatened Species. It is also well- and bird species. The Tanzawa region is a mountainous area known as an umbrella species, which is defined by Fleishman et which consists of Hirugatake (1673 m), Mt. Tanzawa, Sagami al. (2000) as a “species whose conservation confers a protective oyama and Togadake. It cuts across three prefectures: Kana- umbrella to numerous co-occurring species”. gawa, Yamanashi, and Shizuoka, and is designated as a Quasi- National Park. In Japan, the habitat of the local populations has been frag- mented by deforestation because of development of new infra- The selected areas are Mt. Fuji and the Tanzawa region. These structure. Especially, the Tanzawa local population of Asiatic regions are geographically not far apart. However, because of black bear is ranked as “a local population which should be pro- the recent urbanization and new road constructions, the ex- tected” because of its small population size (Japanese Mammals change of genes between the local populations of big mammals, Society, 1997). A project, which aims to create a new linkage especially Asiatic black bear, in these regions has almost ceased between the local populations of Tanzawa and Fuji regions, is (Japanese Mammals Society, 1997). The area of the National in progress (Kanagawa Prefectual Museum of Natural History, Park is considered an appropriate size for large mammal species. 2003). According to observations in 1995 and 1999 by Huygens The park contains various landscapes and is characterized by a et al.