Summary 0[ Recovery of rainforest bird community structure and composition\ in relation to forest succession after slash!and!burn shifting cultivation or jhum\ was studied in Mizoram\ north!east India[ Replicate fallow sites abandoned after shifting cultivation 0\ 4\ 09\ 14 and ¼099 years ago\ were compared with primary evergreen and semi! evergreen forest using transect and quadrat sampling[ 1[ Vegetation variables such as woody plant species richness\ tree density and vertical strati_cation increased with fallow age in a rapid\ non!linear\ asymptotic manner[ Principal components analysis of vegetation variables summarized 81=7) of the variation into two axes] PC0 re~ecting forest development and woody plant succession "variables such as tree density\ woody plant species richness#\ and PC1 depicting bamboo density\ which increased from 0 to 14 years and declined thereafter[ 2[ Bird species richness\ abundance and diversity\ increased rapidly and asymp! totically during succession paralleling vegetation recovery as shown by positive cor! relations with fallow age and PC0 scores of sites[ Bamboo density re~ected by PC1 had a negative e}ect on bird species richness and abundance[ 3[ The bird community similarity "Morisita index# of sites with primary forest also increased asymptotically with fallow age indicating sequential species turnover during succession[ Bird community similarity of sites with primary forest "or between sites# was positively correlated with both physiognomic and~oristic similarities with pri! mary forest "or between sites#[ 4[ The number of bird species in guilds associated with forest development and woody plants "canopy insectivores\ frugivores\ bark feeders# was correlated with PC0 scores of the sites[ Species in other guilds "e[ g[ granivores\ understorey insectivores# appeared to dominate during early and mid!succession[ 5[ The non!linear relationships imply that fallow periods less than a threshold of 14 years for birds\ and about 49Ð64 years for woody plants\ are likely to cause substantial community alteration[ 6[ As 4Ð09!year rotation periods or jhum cycles prevail in many parts of north!east India\ there is a need to protect and conserve tracts of late!successional and primary forest[ Key!words] bird community structure\ habitat structure and~oristics\ human dis! turbance\ rainforest biodiversity conservation\ slash!and!burn[ Journal of Applied Ecology "0887# 24\ 103Ð120
Changes in tree, liana, and understory plant diversity and community composition in five tropical rain forest fragments varying in area (18–2600 ha) and disturbance levels were studied on the Valparai plateau, Western Ghats. Systematic sampling using small quadrats (totaling 4 ha for trees and lianas, 0.16 ha for understory plants) enumerated 312 species in 103 families: 1968 trees (144 species), 2250 lianas (60 species), and 6123 understory plants (108 species). Tree species density, stem density, and basal area were higher in the three larger (> 100 ha) rain forest fragments but were negatively correlated with disturbance scores rather than area per se. Liana species density, stem density, and basal area were higher in moderately disturbed and lower in heavily disturbed fragments than in the three larger fragments. Understory species density was highest in the highly disturbed 18‐ha fragment, due to weedy invasive species occurring with rain forest plants. Nonmetric multidimensional scaling and Mantel tests revealed significant and similar patterns of floristic variation suggesting similar effects of disturbance on community compositional change for the three life‐forms. The five fragments encompassed substantial plant diversity in the regional landscape, harbored at least 70 endemic species (3.21% of the endemic flora of the Western Ghats–Sri Lanka biodiversity hotspot), and supported many endemic and threatened animals. The study indicates the significant conservation value of rain forest fragments in the Western Ghats, signals the need to protect them from further disturbances, and provides useful benchmarks for restoration and monitoring efforts.
The persistence of wide-ranging mammals such as Asian elephants in fragmented landscapes requires extending conservation efforts into human-dominated landscapes around protected areas. Understanding how elephants use such landscapes may help facilitate their movements and reduce conflict incidence. We studied elephants' use of fragmented habitats and ranging patterns of focal herds in a landscape of rainforest fragments embedded in tea, coffee, and Eucalyptus plantations in the Anamalai Hills. Elephant herds entering this landscape were tracked daily between April 2002 and March 2006, resulting in 985 GPS locations of herds obtained across six major habitats. Natural vegetation in rainforest fragments and riparian habitats, despite low coverage in the landscape, was preferred by elephants during the day. At night, elephants preferred riparian vegetation, avoided other habitats such as swamps and settlements, while the remaining habitats were used proportional to availability. Use of rainforest fragments and riparian vegetation increased over three years of study with a corresponding decline in the use of tea monoculture. Among plantation habitats, coffee, and Eucalyptus were used significantly more during wet and dry seasons, respectively. The concentration of elephants along a major riparian system in the center of the landscape emphasized the role of water and food availability in habitat use during the dry season. Protection of rainforest fragments, secondary vegetation along rivers, and regulated and sequential felling (instead of clear-felling) of Eucalyptus along elephant movement routes will help retain forage, cover, and passage routes of elephant herds and may reduce direct human-elephant encounters in such fragmented landscapes.
Slash‐and‐burn shifting cultivation, or jhum, the predominant form of agriculture in the hill tracts of northeast India, is believed to have caused considerable loss of forest cover in the species‐rich tropical rainforests of the region. In this study I sought to understand how rainforest bird communities are affected by shifting cultivation in Mizoram State. I studied bird occurrence and abundance patterns in secondary successional and mature tropical rainforests in a shifting‐cultivation habitat mosaic in Dampa Tiger Reserve. To compare replicate sites in fallows aged 1, 5, 10, 25, and 100 years with undisturbed primary forest, I used systematic strip‐transect sampling over the winter and early summer ( breeding) seasons during 1994–1995. Many forest bird species, especially those with ranges restricted to northeast India, declined in abundance or disappeared in successional fallows that had regenerated for ≤10 years. Birds that colonized or increased in abundance in regrowth habitats were mainly common and widespread species of open‐country and secondary‐forest habitats, and of low importance for conservation. Primary forest was the main habitat for specialized forest birds, intrinsically rare species, and elevational migrants. Although protection and conservation of relatively undisturbed mature forests is imperative in the core area of the reserve, management in the buffer zone for long‐rotation shifting cultivation (>10‐year cycles) instead of plantation of monocultures may be important until alternate means of livelihood are available to cultivators.
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