Local plant species depletion in a tropical dry deciduous forest of northern India

Abstract

The dry tropical ecosystems are among the world's most threatened, and the dry deciduous forest of northern India is being progressively converted to scrub, savannah and grasslands through industrialization, agriculture, fuelwood collection, lopping of trees for fodder and severe grazing/browsing. This habitat destruction threatens the survival of many species. This study examined the demographic instability of tree species in 3-ha permanent plots: at five sites differing in the degree of disturbance. Based on the proportion of seedlings of a species in its total population (seedling + sapling + adults), about 52% of the total 65 species exhibited local demographic instability, and at one or more sites a single individual represented 10 species. The increase in the proportion of declining species with increase in disturbance intensity indicated that local anthropogenic pressure is responsible for the depletion. Apart from stronger protection measures, it is necessary to encourage fuelwood plantations, develop village pastures and reduce livestock numbers.

Effect of Lantana Camara L. Cover on Local Depletion of Tree Population in the Vindhyan Tropical Dry Deciduous Forest of India

“…In the centre of each 10 x 10 m quadrate, a 2 x 2 m area was marked for enumeration of saplings (individuals 3.2 cm to <9.6 cm dbh) and established seedlings (individuals <3.2 cm diameter but ≥ 30 cm height) (Sagar and Singh 2004). Seedlings shorter than 30 cm height were considered ephemeral, and the established seedlings category represented 1 to >3 yr old individuals.…”

“…Seedlings shorter than 30 cm height were considered ephemeral, and the established seedlings category represented 1 to >3 yr old individuals. Stem diameter of adult and sapling individuals was measured at 1.37 m from the ground and for seedlings it was measured at 10 cm above the ground (Sagar and Singh 2004). Thus, all individuals were enumerated and measured by species.…”

“…A ratio of <0.25 (i.e. less than 1 established seedling per 3 mature individuals) was considered to represent severely depleting species population (Sagar & Singh 2004). Percentage decline at different lantana cover class was obtained by the ratio of number of declining species multiplied by 100 to the total number of species present in different lantana cover classes.…”

“…If the ratio of various age groups in a population is known, demography can be used to elucidate the current reproductive status and future trends of that population (Odum 1983;Smith 1996). A large population of young individuals indicates a rapidly expanding population, a more even distribution of age classes a stationary population, and a large population of old individuals a declining population (Odum 1983;Sagar & Singh 2004). We use the above demographic concept in identifying the depleting species in the areas of lantana invasion.…”

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

“…In India and elsewhere in the tropics, large areas of what were once tropical dry forests have already been converted to anthropogenic grasslands as a result of fire, as also to other uses (Murphy and Lugo 1986;Sagar and Singh 2004). It is critical, therefore, to try and understand the role of fire in the conservation and management of these endangered ecosystems (Janzen 1986a).…”