Recovery of tropical rainforest avifauna in relation to vegetation succession following shifting cultivation in Mizoram, north‐east India

Abstract

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

A casa e a roça: socioeconomia, demografia e agricultura em populações quilombolas do Vale do Ribeira, São Paulo, Brasil

“…Nas duas últimas décadas, essa expansão tem recebido grande atenção devido ao seu papel no desflorestamento das regiões tropicais (Skole et al, 1994;Angelsen, 1995;Brady, 1996;Brown e Schreckenberg, 1998), na perda de biodiversidade (de Jong, 1997) e no aquecimento global (Fearnside e Guimarães, 1996;Tinker et al, 1996;Fox et al, 2000). Por outro lado, muitos estudos vêm demonstrando que a interferência humana no processo sucessional da floresta, por meio das atividades agrícolas, acaba funcionando como fonte de variabilidade, mantendo ou mesmo promovendo a biodiversidade regional (Andrade e Rubio-Torgler, 1994;Neves, 1995;Raman et al, 1998;Steinberg, 1998;Moguel e Toledo, 1999;Altieri, 1999;Gupta, 2000).…”

The mammalian communities in coffee plantations around a protected area in the Western Ghats, India

“…People have been clearing and burning forests for shifting cultivation for millennia (Gadgil and Meher-Homji 1985;Schule 1990), though this is now a dying practice in most parts of the country except in the northeast (Raman et al 1998). Nonetheless, forest-dependent communities continue to burn forests to promote the growth of fresh fodder for grazing (Gadgil and Meher-Homji 1985), and to facilitate the collection of non timber forest products (Rodgers 1986;Saha 2002).…”

“…One of the few well-documented examples of the link between fire and invasive species in India comes from the northeast, where shifting cultivation, or jhum, continues to be the primary form of cultivation (Raman et al 1998). Ramakrishnan and Vitousek (1989) reviewed the impacts of shortened intervals between jhum cycles (down to 4-5 years from the earlier >20-30 years) on species regeneration.…”

Edge Responses of Tropical and Temperate Birds

“…Similarly, the successional vegetation that results from practices such as shifting cultivation (i.e., slashand-burn) or from the abandonment of "permanent" agriculture can be colonized by forest birds. Species richness and abundance have been found to parallel recovery of vegetation (Bowman et al 1990, Blan�espoor 1991, Andrade and Rubio-Torgler 1994, Raman et al 1998. Secondary forest regrowths from agricultural fallows can contain a significant proportion of forest avifauna, as well as secondary-growth specialists (Blan�espoor 1991, Raman et al 1998).…”

“…Species richness and abundance have been found to parallel recovery of vegetation (Bowman et al 1990, Blan�espoor 1991, Andrade and Rubio-Torgler 1994, Raman et al 1998. Secondary forest regrowths from agricultural fallows can contain a significant proportion of forest avifauna, as well as secondary-growth specialists (Blan�espoor 1991, Raman et al 1998). However, these habitats are still suboptimal for forestdependent species (Raman 2001), whereas traditional systems of shifting agriculture practiced on small scales, with long intervals between burning and recropping, may minimally affect the avifauna (Zhijun and Young 2003).…”