A preliminary assessment of the habitat selection of two Palaearctic migrant passerine species in West Africa

We investigated the habitat selected by two Palaearctic migrants (Pied Flycatcher, Ficedula hypoleuca, Willow Warbler, Phylloscopus trochilus) in a patchy landscape in Ivory Coast and compared it with the habitat selection of Afrotropical species in the same foraging guilds. Transect counts were used to test the hypothesis that migrants use more open and more seasonal habitats and have a broader use of habitats compared with resident species. Habitats compared were, in order of decreasing tree density, gallery forest, an isolated forest and bush/tree savanna. The isolated forest had the most pronounced seasonal changes (deciduous trees) and was the one with the most diverse vegetation structure. The habitat where both migrants were most frequent was the isolated forest, and thus occurred in the habitat with the most pronounced seasonal change. Diversity of habitats selected was highest in migrants but in the Pied Flycatcher this was possibly an artefact due to subdominant individuals being excluded from the preferred habitat by territorial birds. Potential competition for habitat with Afrotropical species was found to be low.     

Large Bird Declines with Increasing Human Pressure in Savanna Woodlands (Burkina Faso)

The impacts of human pressure, habitat changes, and efficiency of conservation measures on the non-passerine bird community were assessed in the Sudanian belt of Burkina Faso. Three regions with increasingly large protected areas and higher conservation status were compared. In each region, natural savanna woodlands were also compared to traditionally cultivated areas. Six groups of diurnal raptors and six groups of other large bird species were counted along 167 5-km transect counts during the dry season. Within savanna woodlands, the only significant and consistent declines from the little disturbed Eastern National Parks to the more populated and exploited Western forest reserves were those of the largest terrestrial game birds (Guinea fowl, Bustard, Ground Hornbill), eagles and vultures, which became virtually extinct in the least protected areas. Although some species groups maintained substantial, if not higher populations in cultivated areas (rollers, non-game terrestrial birds, several raptors), the overall abundance of both raptor and non-raptor species declined markedly (50–65%) from natural savanna woodlands to tree-dotted cultivated and fallow fields. Again large game birds, eagles and vultures were absent from every agricultural areas censused. Yet, all of them were still commonly recorded in the same natural and cultivated areas during surveys I conducted in the same regions from 1968 to 1973. The main factors correlated with large bird extinctions or declines from national parks to mere forest reserves and from natural woodlands to fields were first related to hunting, then to habitat degradation and fragmentation through intensive cattle grazing and wood cutting and extension of cultivated areas.     

Winter bird communities in the northern Negev: species dispersal patterns, habitat use and implications for habitat conservation

Bird habitat conservation may require different management strategies for different seasonal bird assemblages. We studied habitat use by winter birds in forest and scrubland habitat patches in the northern Negev, Israel. Our goal was to assess whether differences in responses to landscape and habitat structure between breeding and non-breeding seasons require changes in future conservation plans that have been suggested for the Negev breeding bird community. We evaluated habitat and area effects on bird abundance and distribution and tested whether species habitat use during winter involves niche shifts. Compared with breeding birds, a larger proportion of winter bird species occupied both scrubland and forest. As in summer, forest bird species responded to habitat structure, whereas scrubland species were associated with both habitat structure and area. Resident birds disperse into habitats in which they were not present during summer. Consequently, for several species, the correlation between bird densities and environmental factors showed a better fit at the landscape rather than at the habitat scale. In addition, rather than niche shift, birds actually extended their niche breadth. Nest site selection may constrain bird distribution into a realized niche, smaller than their fundamental niche. Despite the scale differences in habitat use, the similar species diversity patterns between seasons suggest that both winter and summer birds would benefit from conservation of scrub patches larger than 50 ha, and enrichment of foliage layers within the planted forests.     

Avian responses to forest fragmentation during the breeding and non-breeding seasons

Forest fragmentation represents a threat to several bird species worldwide. Several factors can change across seasons (e.g. bird perception of the landscape, weather conditions, biotic interactions), which can modify the response of bird populations to forest fragmentation. However, most studies have been conducted only during the breeding season. Here we assessed the relationship between forest fragmentation (patch area and patch isolation) with population abundances of resident species during both the breeding and the non-breeding seasons. Bird population abundances (all species in the community, subsets of forest and habitat generalist species and for individual species) were estimated across a gradient of area-isolation in a semi-arid forest in Cordoba, Argentina. Population abundance of the overall avian community and of the subset of forest species declined with patch area reduction independently of the season. By contrast, the subset of habitat generalist species was not affected by patch area reduction or by the increase in patch isolation, either during the breeding or during the non-breeding season. When the analyses were carried out for individual species, we found four forest species and one habitat generalist species whose responses (the relationship between population abundance and patch area or with isolation) were different between breeding and non-breeding seasons. The negative effects of forest fragmentation were found mainly during the breeding season. Our results suggest that reduction of patch area may lead to a reduction of more than 65% of the population abundance of forest bird species, during both the breeding and the non-breeding season. Therefore, there is an urgent need to conserve large forest patches within the region as irreplaceable elements for the conservation of populations of several species.     

Seasonal use of remnant forest fragments by understorey forest birds in the Uluguru Mountains,Tanzania: a conservation priority

Forest fragmentation can lead to extinctions of some species at local levels and is eroding bird diversity at an increasing rate. While there is information on the distribution of forest bird species in most of the Eastern Arc Mountain forests, some forests, particularly the smaller fragments, have not been adequately surveyed. Using mist netting we surveyed avifauna in some of the poorly known forests (12.5–25 ha) located 320–1 300 m above sea level in the Uluguru Mountains in order to address their conservation importance. Proportions of seasonal altitudinal migrants were significantly higher in these lower-altitude forests during the cold season than the hot season. The results suggest that these forests support bird species of conservation concern, most of which are forest dependent and some of which make seasonal movements between high-altitude montane forests and lowland/ foothill forests. These forests are important cold-season habitat of altitudinal migrants and further fragmentation should be halted as a matter of regional and global priority.     

千岛湖陆桥岛屿鸟类集团对栖息地片段化的敏感性及其季节变化

为探究千岛湖陆桥岛屿不同鸟类集团对栖息地片段化敏感性的差异和季节变化,于2009年4月—2012年1月鸟类繁殖季(4、5、6月)和冬季(11、12、1月)对千岛湖41个陆桥岛屿鸟类集团进行了研究。结果表明,冬季杂食鸟对片段化敏感性高于食虫鸟,繁殖季时二者无显著差异,繁殖季和冬季时下层鸟对片段化敏感性均高于林冠鸟,冬季留鸟对片段化敏感性高于候鸟,繁殖季则无显著差异。杂食鸟和留鸟对片段化敏感性存在季节差异,而食虫鸟、林冠鸟、下层鸟和候鸟对片段化敏感性均无季节差异。不同鸟类集团对栖息地片段化敏感性的差异和季节变化规律,有助于人们在栖息地管理和保护区设计时采取更有针对性的鸟类保护措施。     

Effects of habitat,season, and age on winter fat storage by migrant and resident birds in Jamaica

Most small birds wintering in the tropics should show little subcutaneous fat deposition (SFD), except in habitats where food availability may decline in late winter or, for some resident species, to prepare for incubation or brooding fasts. However, these predictions need re‐examination in light of a new, precise, cross‐validated method to compare SFD among habitats and species. We sampled 170 Nearctic‐Neotropical migrant and 279 resident birds during early and late winter in 1993 and 1994 in Jamaica, West Indies. Habitats, from greatest to least expected availability of insect prey, were (1) mangrove forest, (2) montane/foothills forest and cultivation, (3) dry limestone forest, and (4) acacia scrub. Percent lipid, estimated from multiple‐regression models using visual fat scoring (0–8 scale), total‐body electrical conductivity, and a variety of morphometrics, was categorized by percentile ranks to determine if SFD varied by habitat, season, or age for all species, resident species, migrant species, and several individual species. SFD averaged ~ 13% total mass for all birds, ranging from 8–24% for well‐sampled species. The few bird species in acacia scrub, primarily two facultative long‐distance migrants, averaged ~ 26% lipid content, significantly more than birds in other habitats. Most birds did not vary in SFD in the other three habitats, although Common Yellowthroats (Geothlypis trichas) had greater SFD in dry limestone habitat than in montane habitat. Bananaquits (Coereba flaveola) and Jamaican Euphonias (Euphonia jamaica) in montane habitat, especially in early winter, had higher SFD than other resident species. Contrary to our prediction, adults and juveniles had similar SFD, with the exception of juveniles having more SFD than adults in acacia scrub habitat. Winter fat deposition (or, in some cases, muscle‐protein catabolism) in the tropics may be an overlooked strategy, potentially important as a hedge against fasting for floaters, facultative migrants, some territorial migrants in habitats with seasonal declines in food resources, and some resident species prior to breeding.     

基于鸟类栖息地季节性变化的自然保护区动态分区管理——以安徽升金湖国家级自然保护区为例

鸟类栖息地会随着季节迁徙而改变,基于此对以珍稀濒危鸟类保护为主要目标的自然保护区进行动态分区管理,能够有效提高土地利用效率,协调生物多样性保护与其他生态系统服务功能利用。通过MaxEnt模型分析预测安徽升金湖国家级自然保护区鸟类繁殖季和越冬季的栖息地范围,并采用空间叠加分析方法得到动态分区方案。结果发现：繁殖季鸟类栖息地适宜性受到人口密度、丰水期土地利用类型、距居民点距离、距道路距离等环境因素的影响;越冬季鸟类受到距道路距离、人口密度、距枯水期水体距离、枯水期土地利用类型等环境因素的影响。运用ArcGIS水文工具分析出升金湖国家级自然保护区汇水单元作为其动态区划单元,根据鸟类栖息地季节性变化的特点结合分析结果叠加分析,将安徽升金湖国家级自然保护区划分为核心栖息地保护区、繁殖季栖息地保护区、越冬季栖息地保护区和一般控制区。核心栖息地保护区要进行全年严格保护,繁殖季栖息地保护区和越冬季栖息地保护区在相应鸟类栖息时段严格管控、非栖息时段可合理利用,一般控制区则全年可允许合理的行为活动。季节性动态分区方案注重解决安徽省升金湖国家级自然保护区生态环境保护和社区发展之间的矛盾问题,便于未来保护区生态保护规划决策的制定和实施,进一步丰富了以季节性栖息物种为主要保护对象的自然保护区的动态功能分区研究理论与方法体系,为制定提高自然保护区空间利用效率的生态管理策略提供了参考依据。综上,建议在升金湖国家级自然保护区生态环境保护和社区发展中,依据保护区季节性动态分区特征,实行分区管制,制定对应的生态环境保护和发展的措施。     

Process in the evolution of bird migration and pattern in avian ecogeography

Current ideas about the evolution of bird migration equate its origin with the first appearance of fully migratory populations, and attribute its evolution to a selective advantage generated by increased breeding success, gained through temporary emigration from resident populations to breed in under-exploited seasonal areas. I propose an alternative hypothesis in which migration first appears as a temporary directional shift away from the breeding site outside the reproductive period, in response to seasonal variation in the direction and/or severity of environmental gradients. Fully migratory populations then appear through either extinction of sedentary phenotypes, or colonisation of vacant seasonal areas by migrants. Where colonisation occurs, resident ancestral populations can be driven to extinction by competition from migrants which invade their range outside the breeding season, resulting in fully migratory species. An analogous process drives the evolution of migration between high latitudes and the tropics, since extension of breeding range into higher latitudes may drive low latitude populations to extinction, resulting in an overall shift of breeding range. This process can explain reverse latitudinal gradients in avian diversity in the temperate zone, since the breeding ranges of migratory species concentrate in latitudes where they enjoy the highest breeding success. Near absence of forest-dwelling species among Palaearctic-African migrants is attributable to the lack of forest in northern Africa for much of the Tertiary, which has precluded selection both for southward extension of migration by west Palaearctic forest species, and northward breeding colonisation by African forest species.     

Response of a raptor community to shrinking area and degradation of tropical rain forest in the south western Ghâts (India)

The influence of irregular or incomplete fragmentation and increasing degradation of natural rain forest on diurnal raptor community was studied in the northern part of the western Ghâts in southwestern India A census of mainly territorial breeding pairs on 400 ha sample quadrats was associated with a measure of the percent cover of the main habitat types and a degree of forest fragmentation including irregular patch shape and habitat heterogeneity
Four groups of 3-4 species were defined according to their decreasing tolerance to forest fragmentation and disturbance, from mostly open grassland species to interior forest specialists Habitat selection, density and sensitivity to landscape structure were investigated The community composition and dynamic of each habitat were the sum of these specific reactions The distribution of species along the succession of increasing fragmentation and forest degradation was thus found to be non random, but did not follow a nested subset pattern The density of forest species declined with forest patch size possibly because of the irregular patch shape, the increased edge effects and the consequent increase of linear distance for a bird to cover within its territory However, sensitivity to habitat structure and disturbance was found to be even higher than sensitivity to area per se The need to conserve the largest patches of little disturbed forest is emphasized, as well as the conservation value of woodlots-open habitat mosaics that are suitable for a different set of species     

Restoring Savanna Using Fire: Impact on the Breeding Bird Community

Restoration of many terrestrial plant communities involves the reintroduction of fire. However, there have been few studies of the effects of fire on the avifauna during the restoration process. To study the effects of oak savanna restoration on avian communities, breeding birds were censused and the vegetation structure documented in seven experimental burn units (8–18 ha) that had experienced different frequencies of controlled burns during the past 31 years (0–26 burns). Data were analyzed with both direct and indirect gradient analyses using multivariate techniques. The results showed that, as savanna restoration proceeded, there was a general decline in predominantly insectivorous species, particularly those that feed in the upper canopy region (leaves and air space), and a general increase in omnivorous species, particularly those that feed on the ground and in the lower canopy. Insectivorous bark gleaners (woodpeckers) also increased during restoration and were correlated with the increase in standing dead trees resulting from the fires. Overall, savanna restoration resulted in increases in the abundance of many open country bird species, including many species that have been declining in central and eastern North America, including red‐headed woodpecker, Baltimore oriole, eastern kingbird, vesper sparrow, field sparrow, lark sparrow, brown thrasher, American goldfinch, and brown‐headed cowbird. The shifts in species and guilds were correlated with changes in burn frequency and the macro vegetation structure—tree and shrub density, leaf area index, and relative proportion of standing dead trees. The findings show that savanna restoration can increase bird diversity and provide important habitat for uncommon or declining bird species. These birds are most likely attracted to one or more of the distinctive habitat features of the restored savanna environments, including scattered mature trees, standing dead trees and snags, and presence of both shrubby and grassland vegetation. The findings also suggest that restoration ecologists and wildlife biologists will need to work together to achieve desired goals, since different types of savanna restoration efforts may produce different effects on the breeding bird community.     

Status and diurnal activity budget of non-breeding White-headed Ducks Oxyura leucocephala in Algeria

In Algeria, the Globally Endangered White-headed Duck Oxyura leucocephala is resident throughout the year in the coastal wetlands of north-east Algeria and the Hauts Plateaux, where it occupies habitats that range from freshwater ponds and brackish marshes to hypersaline lakes. In autumn and winter, at two study sites sleeping (49% and 68%) and resting (9% and 20%) dominated, whereas feeding (7% and 10%) represented a minor proportion of, diurnal activities. There was no marked seasonal change in the activity pattern, as would be expected for a resident bird. The breeding and winter distributions of the species were similar, but seasonal and diel patterns of dispersion among habitats remain poorly known. Human encroachment on wetland habitat, habitat degradation and illegal hunting in protected areas are the major threats to the persistence of the species and probably similar threatened species in Algeria.     

Heterospecific attraction and food resources in migrants' breeding patch selection in northern boreal forest

We studied experimentally how heterospecific attraction may affect habitat selection of migrant passerine birds in Finnish Lapland. We manipulated the densities of resident tit species (Parus spp.). In four study plots residents were removed before the arrival of the migrants in the first study year, and in four other plots their densities were increased by releasing caught individuals. In the second year the treatments of the areas were reversed, allowing paired comparisons within each plot. We also investigated the relative abundance of arthropods in the study plots by the sweep-net method. This allowed us to estimate the effect of food resources on the abundance of birds. The heterospecific attraction hypothesis predicts that densities of migrant species (especially habitat generalists) would be higher during increased resident density. Results supported this prediction. Densities and number of the most abundant migrant species were significantly higher when resident density was increased than when they were removed. On the species level the redwing (Turdus iliacus) showed the strongest positive response to the increased abundance of tits. Migrant bird abundances seemed not to vary in parallel with relative arthropod abundance, with the exception of the pied flycatcher (Ficedula hypoleuca) which showed a strongly positive correlation with many arthropod groups. The results of the experiment indicate that migrants can use resident tit species as a cue to a profitable breeding patch. The relationship between the abundance of the birds and arthropods suggests that annual changes in food resources during the breeding season probably do not have a very important effect on bird populations in these areas. The results stress the importance of positive interspecific interactions in structuring northern breeding bird communities. Received: 1 September 1997 / Accepted: 22 January 1998     

Seasonal changes in bird species diversity at the interface between forest and reed-bed

Habitat edges are landscape structures that have a major influence on animal communities. Bird communities' response to habitat edges is influenced by the season and habitat characteristics but it is still poorly understood how communities respond to structural complex (i.e. natural) edges. Inter-seasonal changes in bird species diversity were quantified at a homogeneous, sharp interface between two habitats that host distinct and well-represented bird communities: a mature broad-leaved forest and a compact reed-bed area. Resident species diversity was found higher during winter, both in terms of species richness and evenness. The presence of the reed-bed nesting migrants during the summer season did not notably modify the seasonally reversed diversity pattern; the overall evenness was higher during the winter season while the overall species richness did not differ between the two seasons. Thus, contrary to the expected regional seasonal diversity pattern, the forest – reed-bed interface is, in winter, a local bird diversity hotspot. The possible causes and implications for conservation of this phenomenon are discussed.     

Comparing bird assemblages in large and small fragments of the Atlantic Forest hotspots

The Atlantic Forest (AF) is one of the five most threatened and megadiverse world hotspots. It is arguably the most devastated and highly threatened ecosystem on the planet. The vast scope of habitat loss and extreme fragmentation in the AF hotspots has left intact very few extensive and continuous forested fragments. We compared bird assemblages between small (<100 ha) and large (>6,000 ha) forest remnants, in one of the largest AF remnants in Argentina. We performed 84 point-counts of birds in four large fragments (LF) and 67 points in 25 small fragments (SF). We recorded 4,527 bird individuals belonging to 173 species; 2,632 belonging to 153 species in LF and 1,897 in 124 species in SF. Small fragments suffered a significant loss of bird richness, mainly forest dependent species, but the birds abundance did not decrease, due to an increase in abundance of forest independent and semi-dependent bird species (edge and non forest species) that benefit from forest fragmentation. The bird guilds of frugivores, undestory, terrestrial and midstory insectivores, nectarivores and raptors, and the endemic species of AF were area sensitive, decreasing significantly in richness and abundance in the SF. Terrestrial granivores were the only guild positively affected by forest fragmentation, containing mainly edge species, which forage in open areas or borders including crops. Our first observations on fragmentation effects on bird assemblages in the southernmost Argentinean Atlantic Forests did not validate the hypothesis on pre-adaptation to human disturbances in the bird communities of AF. On the contrary, we observed that forest dependent, endemic and several sensitive bird guilds were strongly affected by fragmentation, putting in evidence the vulnerability to the fragmentation process and the necessity to conserve large remnants to avoid reduction of the high biodiversity of AF birds.     

Demographic and spatial responses of resident bird populations to the arrival of migratory birds within an urban environment

Long-distance migration allows many bird species to overcome the severe climatic changes that occur in seasonal environments. Migration is highly demanding, and given its cyclical nature, we currently know that it has substantial effects on the population parameters of migratory birds during both breeding and wintering seasons. However, the potential effects of the presence of migratory birds in their wintering grounds on populations of resident birds have remain largely unexplored. Here, we propose the hypothesis that migratory birds negatively affect the habitat occupancy and population abundance of resident birds because of the arrival of numerous individuals during the most limiting months of the year. Here, we studied different species of migratory and resident birds that coexist during winter in an urban ecological reserve located within Mexico City. We used single-species multiseason occupancy models, two-species occupancy models, and distance sampling techniques to evaluate changes in occupancy and population density of resident bird species during three consecutive winters. We found an aggregation pattern between two resident species (Psaltriparus minimus and Thryomanes bewickii) with three migratory warblers (Cardellina pusilla, Setophaga coronata and Setophaga townsendi). Thus, our results provide evidence of the formation of mixed-species flocks in our study area. We also conclude that resident birds experience different demographic and behavioral processes during winter that not necessarily result from interspecific interactions with migratory birds.     

Bird diversity in the savanna habitats of Akagera National Park,Rwanda, in the post-war recovery period

The biodiversity of Akagera National Park (ANP), Rwanda, has reportedly been declining since 1990 due to conflict and war in the country between 1990 and 1994. In this paper, we describe bird diversity in the post-war recovery period. We used systematic plots, point counts and presence–absence surveys to estimate bird species richness and diversity in acacia savanna habitats of the park between 2009 and 2011. We recorded a total number of 301 species, of which 75% were resident and 22% migrant, including a large number of Palearctic visitors and Afrotropical migrants. Particularly notable were four endemic species of the Lake Victoria region, four globally threatened and nine near-threatened species as well as species that had not previously been recorded in the park and those overlooked by past records. Estimated species richness and diversity at the landscape level were 346 and 0.98, respectively, mean estimates per plot were 42 and 0.86 for species richness and diversity, respectively. Our results highlight regional and international importance of ANP in protecting important bird diversity. We also emphasise that ANP is the only savanna habitat in Rwanda where typical savanna birds occur. Our findings provide new insights for further strengthening of efforts to conserve the park's biodiversity.     

Energy availability, abundance, energy-use and species richness in forest bird communities: a test of the species–energy theory

Aim To test the ‘more individuals hypothesis’ as a mechanism for the positive association between energy availability and species richness. This hypothesis predicts that total density and energy use in communities is linearly related to energy availability, and that species richness is a positive function of increased density. We also evaluate whether similar energy–density patterns apply to different migratory groups (residents, short‐distance migrants and tropical migrants) separately. Location European and North American forest bird communities. Methods We collected published breeding bird census data from Europe and North America (n = 187). From each census data we calculated bird density (pairs 10 ha^?1), energy use by the community (the sum of metabolic needs of individuals, Watts 10 ha^?1) and geographical location with an accuracy of 0.5°. For each bird census data coordinate we extracted the corresponding monthly values of actual evapotranspiration (AET). From these values we calculated corresponding AET values that we expected to explain the density energy use of forest birds: total annual, breeding season (June) and winter AET. We used general linear modelling to analyse these data controlling for the area of census plots, forest type and census method. Results Total density and energy use in European and North American forest bird communities were linear functions of annual productivity, and increased density and energy use then translated into more species. Also resident bird density and energy consumption were positive functions of annual productivity, but the relationship between productivity and density as well as between productivity and energy use was weaker for migrants. Main conclusions Our results are consistent with the more individuals hypothesis that density and energy use in breeding forest bird communities is coupled tightly with the productivity of the environment, and that increased density and energy consumption results in more species. However, not all community members (migratory groups) are limited by productivity on the breeding grounds.     

西双版纳茶林及橡胶林区鸟类调查

1983年5—7月,作者对云南省西双版纳的勐海、勐养和勐腊三个地区的茶林和橡胶林区的鸟类区系组成情况进行了调查,其结果若与开发前（郑作新、郑宝赉,1961,1962;A.И.伊万诺夫,1961）的记录对照,在季节时间上有所不同,但该地区的热带雨林和季雨林被开垦种植为茶林、橡胶林及其它经济作物之后,反映出各林区现在的繁殖鸟种类减少很多,鸟类区系组成情况有显著的变化。     

How Well Will Brazil's System of Atlantic Forest Reserves Maintain Viable Bird Populations?

It is crucial for biodiversity conservation that protected areas are large and effective enough to support viable populations of their original species. We used a point count distance sampling method to estimate population sizes of a range of bird species in three Atlantic forest protected areas of size 5600, 22,500, and 46,050 ha. Population sizes were generally related to reserve area, although in the mid-sized reserve, there were many rare species reflecting a high degree of habitat heterogeneity. The proportions of forest species having estimated populations >500 ranged from 55% of 210 species in the largest reserve to just 25% of 140 species in the smallest reserve. All forest species in the largest reserves had expected populations >100, but in the small reserve, 28% (38 species) had populations <100 individuals. Atlantic forest endemics were no more or less likely to have small populations than widespread species. There are 79 reserves (>1000 ha) in the Atlantic forest lowlands. However, all but three reserves in the north of the region (Espírito Santo and states north) are smaller than 10,000 ha, and we predict serious levels of local extinction from these reserves. Habitat heterogeneity within reserves may promote species richness within them, but it may also be important in determining species loss over time by suppressing populations of individual species. We suggest that most reserves in the region are so small that homogeneity in the habitat/altitude within them is beneficial for maintenance of their (comparatively small) original species compliment. A lack of protection in the north, continued detrimental human activity inside reserves, and our poor knowledge of how well the reserve system protects individual taxa, are crucial considerations in biodiversity management in the region.