Current Status and Conservation of Falconiformes in Tropical Asia
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j. RaptorRes'. 32(1):40-55 ¸ 1998 The Raptor ResearchFoundation, Inc. CURRENT STATUS AND CONSERVATION OF FALCONIFORMES IN TROPICAL ASIA JEAN-MARCTHIOLLAY Laboratoired•cologie, E.N.S., 46, rue d'Ulm 75230Paris Cedex05, F'rance ABSTRACT.--Ireviewed the distribution, abundance, habitat selection,and population trends of 69 di- urnal raptors found in 13 subregionsfrom India to Indochina, Sumatra,and Java.At least four species are Endangered or Vulnerable and 19 are at lower risk or have insufficient data to determine their status.Among 49 breeding species,33 have a world range mostly within South Asia, half with high conservationvalue scores.Others have small (six species)or substantial(10 species)populations but a much wider distribution. Of all 69 taxa, eight are mature forest-interior species,six are associatedwith gapsor disturbance,14 are woodland,edge, or upper canopydwellers, 14 are associatedwith grasslands or cultivation,and sevenare river or wetland species.Most wintering migrants(20) are nonforestspecies. There is evidence of largescalepopulation declineson the continent of Asia, as well as insular syndrome involvingincreased density and wider habitat breadth on islands.The most important threatsto diurnal raptorsare (1) habitat loss,especially of lowland rainforestto cultivation,(2) habitat degradation,mainly from logging, and (3) forest fragmentation. Few speciesare successfullyadapting to new man-made habitats and none are from the forest-interiorguild. Main conservationpriorities include surveysand ecologicalstudies, extension and enforcement of protected areas, and sustainablelogging practices. KEYWORDS: raptorpopulations; South Asia; distritmtion;(vnservation. Estadoactual y conservaci6nde falconiformesen el Asia tropical REStJMEN.--Resumila distribuci6n, abundancia, selecci6n de habitat, y tendenciaspoblacionales de 69 aves rapaces diurnas de 13 subregionesdesde India hasta Indochina, Sumatra, y Java. Por lo menos 4 especiesestrin amenazadaso son vulnerables, 19 estrin en menos riesgo o no existe infbrmaci6n sufi- ciente para determinar su estado. Entre las 49 especies,33 tienen un rirea de distribuci6n dentro del Sur de Asia, la mitad de estastienen un valor de conservaci6nalto. Otras tienen poblacionesreducidas (6 especies)o substanciales(10 especies)con distribucionesmas amplias.De todos los 69 taxones,8 son especiesdel interior de bosquesmaduros, 6 estan asociadosa zonas abiertas o disturbadas,14 son especiesde bosque,borde o dosel,14 est•n asociadosa pastizaleso cultivos,y 7 son especiesde rios o humedales. Casi todas las migratorias (20) no son especiesde bosque. Existen evidenciassobre la dis- minuci6n poblacional de las especiesa gran escalaen el continente Asiritico,como tambien sobre el sindrome insular que incluye el aumento de densidadesy espaciosentre habitatsen islas.Las amenazas masimportantes para las avesrapaces diurnas son: (1) P•rdida de habitat, especialmentede los bosques de 11uviade tierras bajas convertidasa cultivos, (2) degradaci6n del habitat a partir de actividades forestales,y (3) fragmentaci6ndel bosque.Pocas especies se estrinadaptando exitosamente a los nuevos habitats creados por el hombre. Las prioridades de conservaci6n,incluyen investigacionesy estudios eco16gicos,apoyo y extensi6n de rireasprotegidas y prricticasforestales sostenibles. [Traducci6n de C•sar Mrirquez] Several Asian countries have the densest and fas- quirements, prey selection and degrees of toler- test growing human populationsin the world, as ance to disturbance,and their speciesnumbers, at well as the fastest growing economies and stan- least in some areas, are correlated with the total dards of living. As a result, there is dramatic pres- bird speciesrichness (Thiollay 1997). My aim here sure on natural habitats, resources, and biodiver- is to review the composition,distribution, popula- sity of this area. tion levels, and conservation priorities of diurnal Raptors are good indicators of environmental raptors in SoutheastAsia in the early 1990s. Most changesbecause they are top predators, they in- information about the geographicaldistribution of clude specieswith a variety of specifichabitat re- raptor speciesis scattered in the literature and 40 MARCH 1998 STATUS OF RAPTORS IN TROPICAL ASI• 41 TIBET CHINA BURMA THAILAND I NSRI LANKA Figure 1. Study area and regional divisions. much less is known about their habitat selection to Vietnam), and Sundan (Malaysia to Java). In terms of and their actual abundances. These last critical its raptors, the area can be divided more preciselyinto 13 subregions(Table 1). components of their status are rapidly changing The main vegetation type is a rich, closed-canopy, and may be different today than they were report- moist forest with trees approximately 50 m in height ed in regional synthesesbased on information that (Whitmore 1985). At best,only 42% of the originalforest is decadesold. To update and complement pub- remains (global estimate from Collins et al. [1991], as- lished data, I shall rely primarily on the resultsof suming a constant deforestation rate since the 1980s). This estimateincludes evergreen to semi-deciduous,low- numerouspersonal raptor surveysand field studies land and montane forests that have often already been carried out in 27 statesor provincesin eight coun- logged or degraded, where annual rainfall is 2-4 m or tries during the last 20 yr. more and no month receivesunder 60 mm of precipi- tation. At higher latitudes, marked dry seasons (<3 STUDY AREA months with <60 mm of rainfall) result in drier, more The area under consideration extends from India to deciduous monsoon forests grading into lower wood- Indochina, south of the Himalayasand China, and down lands or even subdesert scrubland in north western In- to the Greater Sundas,west of the Wallace Line (Fig. 1). dia. Lowland swampforests are locally extensivein Bor- This is a faunisticallyhomogeneous, 7 million-km2 re- neo and Sumatra. Mangroves(Avicennia, Rhizophora) are gion, that now has a human population of > 1.4 billion widespreadalong low coastlinesand estuariesand cover people. It is divided into three broad biogeographic over 4000 km2 in the Sundarbansof Bangladeshalone zones: Indian (India to Burma), lndochinese (Thailand Former coastal forests have been replaced by coconut 42 THIOLLAY Vo•. 32, No. 1 Table 1. Total sizeof studyareas, remaining forested areas (1980-88), and existingprotected areas in 1000sof km9 (from Collins et al. 1991). MANGROVE LAND RAIN MONSOON AND SWAMP PROTECTED SUBREGIONS AREA FOREST FOREST1 FOREST AREAS9 Northern India • 1805.9 0.9 98.1 1.2 106.0 Peninsular India 944.6 20.0 18.4 0.1 16.6 Northeastern India t' 640.4 46.7 38.8 4.5 9.3 Sn Lanka 64.7 1.4 10.8 7.2 Andamans-Nicobars 6.3 2.6 3.6 0.6 0.6 Burma (Myanmar) 657.7 220.3 88.4 3.0 7.0 Thailand + Cambodia 688.3 127.4 79.2 13.4 66.9 Laos + Vietnam 556.1 134.3 45.3 1.6 8.2 Peninsular Malaysiac 330.3 64.5 5.2 6.2 Northern Borneo 203.9 113.5 21.7 8.1 Kahmantan 532.1 323.6 73.7 29.7 Sumatra d 472.6 155.3 75.3 45.0 Java + Bali 138.6 12.8 9.2 3.7 Total 7041 1223 382 209 314 Includesboth lowland and montane forest, and from intact to highly degradedstands. Includesalso nonforest areas and low protectionstatus areas such as protectionforests or hunting reserves. North of 20øN,excluding Himalayan and Tibetan ranges. IncludesBangladesh. Includes PeninsularThailand, Tenasserimand Singapore. Includesoutlying islands. plantations. Upper montane areas above tree line are in- two sets of methods were used to assess the relative abun- significant in size. dance and habitat selection of raptors. First, extensive Wetlandsare mostlyassociated with riversand to a less- transectcounts were made along roads,tracks, and forest er extent with marshes, peat swamps,coastal lagoons, trails, either by car with numerous stopsor on foot. The many artificial lakes, and vast areas of temporarily inun- second method was an adaptation of the point count dated ricefields. Permanent agriculture is often intensive method (Thiollay 1989, 1995) where 1-km$ samplequad- over huge, densely-inhabitedareas. Nevertheless,a sub- rats, predominantlycovered by a singlehabitat type,were stantial density of trees, patches of grassland for cattle censusedfor 4 hr from vantagelookouts during morning grazing, and fallow areas with low second growth are re- periods (0900-1200 H) when most raptors were active tamed. In more remote and fbrested areas on slopes, The resultswere expressedin mean number of individ- shifting cultivation has resulted in various successional uals, respectively,per km of transector per 1-km$ sample stagesof secondary growtit. Tree plantations are often plot. Differences between these abundance indices (with- extensive. They range from the diversified, fbrest-like in, but not between species,because of unequal detect- agroforestsof Indonesia to the vast arid uniform indus- abilities) were tested among habitats and study areas us- trial plantations of fast growing exotic trees growIt for ing Kruskal-Wallisone-way ANOVA, followed by a non- firel or pulpwood (Eucalyptus,Gmelina, and Acada), lum- parametric multiple pair-wise comparison procedure ber ( 7kctona,Pin us, arid Dipteroca•paceae),fruit (Mango), based on two-tailed Mann-Whitney U-tests (Sokal and and especiallyrubber (Hevea) and oil (Elaeis).Together Rohlf 1981). with open cultivatedwoodlands and home gardens,they Habitat types,where each individual raptor wasrecord- currently cover much larger areas than natural forests. ed in cumulative random samples,were used to assess