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Littoral Fish Communities in Lake Tanganyika: Irreplaceable Diversity Supported by Intricate Interactions among Species 总被引:2,自引:0,他引:2
Michio Hori Masta Mukwaya Gashagaza Muderhwa Nshombo Hiroya Kawanabe 《Conservation biology》1993,7(3):657-666
The rocky littoral areas of Lake Tanganyika harbor diverse fish communities, mainly composed of cichlids. Their stability, structure, and organizing mechanism were examined at three locations by census, behavioral observations, and dietary analyses. These fish communities were stable, characterized by their persistence during a 10-year period and resilience after a perturbation. Partitioning of spawning sites among substrate spawners was evident, which might be a factor in their ability to coexist. The fish communities were consistently composed of 12 food-habit groups, but composition of species in each group differed from location to location. Among species of different food-habit groups, facultative commensalisms were prevalent. Although aggressive interactions are common among fishes of the same food-habit group, each predatory fish obtained an advantage in feeding efficiency from the different feeding behaviors of other species of the same group. This mutualism and the facultative commensalism should both increase species richness in different parts of the communities. These intricate interactions among species may be a base of stability of the fish communities. We assert that maintenance of ecological networks among species are most important for conservation of biodiversity in tropical regions. 相似文献
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Naoko Takada-Oikawa Norihisa Katoh Toshio Oshida Sukeo Kawanabe Toshikazu Kaise 《Journal of Material Cycles and Waste Management》2000,2(2):138-142
A potting experiment was carried out to determine the effects of soil amendments containing polysaccharides and earthworms
on a land application system for the purification of animal waste water. The following soil amendments were used: purified
Konjak powder (KP, powder containing glucomannan made from the root system of devil's tongue, Amorphophalus rivieri Dur.), crystallized cellulose (CC), and a mixture of the two (MX). These soil amendments were added to the pots, and then
Chrysanthemum corondria were planted in the earthworm pots (A pots), the nonearthworm pots (B pots), and the control pots (C pots); the first two
plots received primary-treated animal waste water, and the other one received tap water. The following items were then measured:
pH, electrical conductivity, chemical oxygen demand (CODMn), total nitrogen (TN), total phosphorus, the volume of drained water from each pots, the height and dry matter weight of
plants, and the water permeability into the soil. The MX-A pots, i.e., the pots containing both soil amendments and earthworms,
gave good results, especially for water permeability, plant growth, the purification of CODMn, and TN. These results suggest that the presence of soil amendments and earthworms may enhance the improvement of water quality
in land application systems using vegetation.
Received: December 9, 1998 / Accepted: February 8, 2000 相似文献
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