生态学代谢理论研究进展

代谢理论是近年来生态学领域的重要进展,不仅有效地解释了生物的新陈代谢率随个体大小和温度的变化规律,还通过代谢率将个体、种群、群落、生态系统水平上的生物学模式联系起来。介绍了代谢理论的研究历史和主要内容,并通过几个例子说明该理论的应用。     

Some aspects of the ecology of the Groot Letaba River in the Northern Province,South Africa

The aim of this pilot study was to evaluate the current ecological status of the Groot Letaba River and to compare this information with historical data. The objective was to determine the effects of various impacts on the fish populations of the river. This was done by analysing the water quality and by considering the effect of weirs and dams, as well as various illegal angling activities, on the fish community.

The Groot Letaba River is not highly polluted and the decline in its flow seems to be the greatest threat to the system. During a preliminary study to develop the river's resource potential, it was stated that the annual water allocation from Tzaneen Dam was 103.9 million m³/annum for irrigation, 8.4 million m³/annum for domestic and industrial use and 14.7 million m³/annum for environmental purposes. However, the yield from Tzaneen Dam was only 98 million m³/annum, suggesting that more water had been allocated than was available. As a result only 20% of the simulated natural flow is observed at Letaba Ranch Weir at the lower end of the river.

Over the past few years many weirs and dams, none of which have fishways, have been constructed in the Groot Letaba River, impacting on the flow regime and on the migration potential of many fish species. Tiger fish (Hydrocynus vittatus) and the largescale yellowfish (Barbus marequensis) are two of the more prominent species influenced negatively by these barriers. This problem is aggravated by the illegal netting of fish stranded below these barriers during their spawning migrations.     

Morphological aspects of the science of human ecology

Human ecology is the science on interaction of the man with the environment including the social surrounding. In the human ecological morphology biogenic and sociogenic peculiarities are distinguished; they are formed in the phylo- or ontogenesis. Peculiarities of the body integument, proportions, development of the fat component of the body mass etc. are related with the biogenic signs of the phylogenic origin, since they are connected with life in certain climato-natural conditions. These signs have certain analogues among Mammalia. The sociogenic signs of the phylogenic origin include complexes of bepedality, labour and informative-speech activity. They are characteristic for the human being only. The sociogenic peculiarities of the ontogenic origin include certain changes of the organism connected with professional and sporting activities. According to the human organism state, observed in dynamics, it is possible to judge on biogenic and sociogenic consequences of the environmental influences. For this purpose the data of anthropometric observations in newborn are considered to be important. The role of the biogenic changes is followed in the example of shifts of the body dimensions in time, connected with the solar activity cycles; the sociogenic changes are considered in an example of growth processes under conditions of different gas-pollution of the atmosphere with industrial waste.     

Some aspects of the ecology of the desert snail Sphincterochila prophetarum in relation to energy and water flow

Summary Between 1976–1978, we studied the ecology of the Sphincterochila prophetarum, the most common snail, on stony slopes in Northern Negev. Energy and water flow determinations were made at the individual and population levels on a field observation basis and metabolic data were derived from laboratory simulations.The snails are active during 5–7% of the time during the year, while the remaining 95% of the time, the snails are in aestivation under stones. The energy and water inputs during the short feeding periods are very fast. Only 8% of the total energy in the eaten food are assimilated. Eighty-nine percent of the total assimilated energy are utilized in respiration during the various periods of activity and dormancy.The water loss during the feeding and activity period is about 37% of the total annual input. The snails lose twice as much the amount of water during the winter dormancy periods than in the summer dormancy period.Dedicated to Prof. Evenari and Dr. Springer     

Some implications of paleoecology for contemporary ecology

The paleoecological record allows contemporary ecologists to put current phenomena into the context of a longer time-frame, thereby providing the opportunity to evaluate the importance of slowly operating processes, past cyclic or unusual events, disturbance regimes, and historically constrained phenomena. We briefly outline the environmental history of the Quaternary, discuss the spatial and temporal resolution of the paleoecological evidence for biotic change, and summarize data relevant to such current issues as the nature of the biotic community, the role of disturbance, stability versus rapid change, evolutionary theory, explanations of species diversity, and refugia theory. Finally, we offer examples of the utility of paleoecological techniques for ecologists and environmental scientists.