Showing papers on "Biodiversity published in 1982"

A phytosociological analysis of woody species in forest communities of a part of Kumaun Himalaya

Abstract: This paper reports on a detailed phytosociological analysis of forests in the NW catchment of the Gola River in Kumaun Himalaya, 29°19′–29°27′N and 79°32′–79°42′E. Fourteen sites and 56 stands at elevations ranging from 1200 to 2523 m and covering the following five forest types were investigated: Pinus roxburghii, mixed, Quercus leucotrichophora, Q. lanuginosa, and Q. floribunda. The basal cover of the forests differed according to slope position and aspect. The three oak forests had more basal cover than the other two, and Q. lanuginosa had the most. The performance of individual tree and shrub species and the number of saplings and seedlings differed according to slope position and aspect. The mixed forest had the greatest tree diversity, and among the others diversity increased with increasing basal cover. The diversity of trees, saplings, and herb layer was greatest on aspects with intermediate temperature and moisture conditions; whereas that of shrubs and seedlings increased towards the cooler (and wetter) and warmer (and drier) exposures. There was a positive relation between the diversity of shrubs plus seedlings and trees plus saplings in P. roxburghii and mixed forests; whereas this relationship was inverse in the three oak forests. In general, the dominance-diversity curves for the tree layer followed a geometric series conforming to the niche pre-emption situation in communities of low diversity. Among the forests, the regeneration was best in Q. lanuginosa and worst in Q. leucotrichophora.

Phenology of trees in a sub-tropical humid forest in North-Eastern India

Abstract: Phenological observations were made on 122 tree species in a subtropical humid seasonal forest in north-eastern India. The forest had a high proportion of evergreen compared to deciduous species. Leaf-fall of most of the tree species coincided with the dry season. Flushing started towards the end of the dry season for a majority of the tree species, the degree and period of leaflessness varying with the species. Leaf production in the overstorey species extended over a longer period compared to the understorey species. For most of the species, flowering coincided with leaflessness. Proportionately more overstorey species flowered during the dry season and wet season flowering was more characteristic of understorey species. A majority of the species produced fleshy fruits during the wet season. Fruits, produced during the dry season, were mostly dry.

Human Carrying Capacity, Extinctions, and Nature Reserves

Abstract: This paper argues that mankind is rapidly using up mineral reserves polluting the environment and destroying the biological diversity of the planet. The consequences of these actions could be catastrophic to the human race and may bring about the end of industrial civilization. The species diversity on our planet should be preserved because other species provide an array of ecosystem services without which society as we know it could not persist. Few people are aware of these ecosystem services. They include such things as maintenance of the quality of the atmosphere disposal of wastes soil maintenance food from the sea and the control of crop pests. Increased human population growth and per capita consumption lead to habitat destruction such as the paving of natural areas for mans use; the plowing of marginal land which destroys entire communities; the destruction of rain forests; and the pollution of air and water. Nature reserves must play a central role in any solution to the problem of accelerating extinctions. The author argues that the number and size of nature reserves must be increased. Efforts should be made to avoid developing new tracts of land anywhere. Instead they should be converted into reserves and everything possible should be done to make nonreserve areas more hospitable to other species. Human population will have to be controlled and the number of pollutants in the biosphere must be greatly reduced. Without these measures the earth will suffer a catastrophic loss of species.

Lizard Species in Small Mainland Habitat Isolates and Islands off South-western Western Australia

Abstract: Slopes and elevation of the regression of lizard species richness versus area for small ( < 25 ha) isolated areas of 'natural' vegetation in the Western Australian wheatbelt are not significantly different from those for Western Australian continental island groups. Similar-sized coral islands in Houtman Abrolhos, however, have relatively few lizards, and their species richness is independent of area. This is not attributed to ecological instability of coral islands but to the homogeneous habitat of coral islands and the nature of 'strand' lizards. No family of lizards appears to be favoured in small isolates or islands. It is suggested that the ecologically more generalized species predominate in small areas.

Predictors of Vertebrate Species Richness in Nature Reserves in the Western Australian Wheatbelt

Abstract: Species of mammals (excluding bats), passerines and lizards in 20 nature reserves in the Western Australian wheatbelt were grouped according to whether they were recorded only in natural vegetation (u-species) or whether they also ocurred in disturbed situations (d-species). Species richness in the u-and d-groups related differently to reserve variables: for u-species it tended to be principally influenced by variables of reserve area and extent of associated uncleared land; for d-species by vegetation floristic and structure variables. Generally, u-species have a more vulnerable conservation status than d-species and are the major group of species for which nature reserves are established. The different pattern of response of the u- and d-species to variables in nature reserves highlights the need for more knowledge on the ecological, particularly habitat, requirements of species before ecological prerequisites for conservation measures are evaluated.

Altitudinal ranges of Phanerophytes and Chamaephytes in central Chile

Abstract: Considerable changes in the vegetation can be observed in the altitudinal and latitudinal gradients in central Chile, from 400 to 3400 m above sea level and from arid to subhumid regions (31°–34° S). The composition of the vegetation, the relative proportions of life forms, and seasonal activities of the species, help to define bioclimatic areas where climatic data are scanty. The presence or absence of certain species is also useful in the evaluation of human impacts on mountain ecosystems.

The Role of Field Stations in the Preservation of Biological Diversity

Abstract: Field stations should assume a more active role in the preservation of species diversity and intraspecific genetic variation. Because some field stations concentrate scientists in remote places far from major universities, they are often the only source of biological expertise in the area. Others, located in more densely populated regions, may contain the last surviving remnants of natural ecosystems there. Field stations should locate and identify local populations of rare or endangered species and take the necessary steps for their preservation, begin long-term research on the population biology of these species, and offer conservation-oriented courses to students and the general public. (Accepted for publication 23 February 1982)