Community composition and tree population structure in a sub-tropical broad-leaved forest along a disturbance gradient

Abstract

Floristic composition, diversity, dominance and distribution pattern of species and tree population structure were studied in three stands of a sub-tropical wet hill broad-leaved forest of Meghalaya, India, along a disturbance gradient. Tree species diversity declined with increasing disturbance. Disturbed stands showed low equitability or high dominance and the undisturbed stand exhibited high equitability or low dominance. Contagious distribution among the tree species increased with increasing intensity of disturbance. Species showing regular distribution were restricted only to the undisturbed stand. Effect of disturbance on tree population structure was analysed using density-diameter curves. In the disturbed stands tree species showed reverse J-shaped and/or negative exponential curves, while those in the undisturbed stand exhibited sigmoid to bimodal mound shaped curves.

Diversity and structure of the tree community of a fragment of tropical secondary forest of the brazilian Atlantic Forest domain 15 and 40 years after logging

“…This result agrees with the well-known self-thinning process of aging secondary forests in which a declining tree density, mostly caused by mortality rates concentrated on smaller trees (dbh < 10 cm), is highly compensated by the growth of surviving trees (e.g. Crow 1980, Saldarriaga et al 1988, Rao et al 1990, Brown & Lugo 1990, Oliveira Filho et al 1997. Therefore, as forest regeneration proceeds, the average tree size increases while tree density declines.…”

The Effects of Urbanization and Human Disturbance Upon Plant Community Structure and Bird Species Richness, Diversity, and Abundance in a Natural Forested Area (Forest Park) in Portland, Oregon

“…Ecosystems that have been subjected to frequent and/or severe disturbances have been reported to exhibit reduced species diversity (Airola and Buchholz 1984;Dzwonko and Laster 1988;Hoehne 1981;Rao et al 1990;Sharp et al 1986;Solinska-Gomicka and Symonides 1990;Swindel et al 1986). However, moderate levels of human disturbance may cause reductions (Airola and Buchholz 1984;Bagnall 1979;Dzwonko and Laster 1988;Fugate 1994;Greller et al 1990;Iida and Nakashizuka 1995;Katz 1990;Pysek and Pysek 1990;Rao et al 1990;Seidling 1990;Solinska-G6micka and Symonides 1990) or increases in the species diversity of vascular plants Laster 1988, 1989;McBride and Jacobs 1986;Moran 1984).…”

“…However, moderate levels of human disturbance may cause reductions (Airola and Buchholz 1984;Bagnall 1979;Dzwonko and Laster 1988;Fugate 1994;Greller et al 1990;Iida and Nakashizuka 1995;Katz 1990;Pysek and Pysek 1990;Rao et al 1990;Seidling 1990;Solinska-G6micka and Symonides 1990) or increases in the species diversity of vascular plants Laster 1988, 1989;McBride and Jacobs 1986;Moran 1984). These seemingly contradictory reports may be explained by the "intermediate disturbance hypothesis".…”

“…For example, the number of shrub species (richness) decreased (Dzwonko and Laster 1988;James et al 1979;Levenson 1981;Rao et al 1990), although shrub cover increased (Dzwonko and Laster 1988;Matlack 1994;Seidling 1990). Dzwonko and Laster (1988) found that altered 38 distribution of shrubs was not related to the size of the woodland.…”

Floristic Composition, Diversity and Status of Threatened Medicinal Plants in Tropical Forests of Malyagiri Hill Ranges, Eastern Ghats, India

“…Odum (1971) stated that contiguous distribution is the commonest pattern of plant distribution in nature. Kumar and Bhatt (2006) also reported that most species follow contiguous distribution pattern in foot-hills forests of Garhwal Himalaya and Rao et al (1990) had similar findings for tree species of a subtropical forest of north-east India. The Shannon-Wiener index (H') was 3.38 and Simpson's index was 1.0.…”