عنوان

Structural comparison of soil macroinvertebrate microcommunities in selected global ecosystems with special emphasis to land use

TLpq303809151

انگلیسی

Structural comparison of soil macroinvertebrate microcommunities in selected global ecosystems with special emphasis to land use

[Thesis]

S. H. Shakir

D. L. Dindal

State University of New York College of Environmental Science and Forestry

1989

336

Ph.D.

State University of New York College of Environmental Science and Forestry

1989

This thesis is designed to determine and assess the effects of different land-use practices upon the community structure of soil macroinvertebrates under different selected global microecosystems (i.e. desert ecosystems and forest ecosystems). Samples of the fauna and soils were studied from 18 different sites: (a) desert agroecosystems under different irrigation regimes in Egypt; (b) forest plantations fertilized with urea-nitrogen in Germany; (c) forest plantations and old fields in USA. Samples were collected from Spring 1977 through early Summer of 1985. In temperate forest and herbaceous ecosystems in New York, the comparisons of soil macroinvertebrates in different habitats showed significant differences for density and biomass. This may be due to (a) type of litter dominant in different site which affect the availability of food to the fauna; (b) soil physical-chemical factors; (c) forest plantation operations. In temperate spruce forest ecosystems in Germany application of fertilizers caused appearance of six additional taxa. At the same time the biomass of the soil macroinvertebrates increased from 2.3 to 2.9 g/m2. In desert agroecosystems in Egypt agricultural operations vary in their effects on soil faunal density; the beneficial operations were irrigation and fertilization and the deteriorating operations were plowing and tillage of the soil. Diversity of soil macroinvertebrates in all sites was related to (a) complexity of vegetative species; (b) availability of food components; (c) seasonal temperature and rainfall variation; (d) seasonal cycling of fallen litter; (e) microhabitats formed as the result of the fresh litter types and the litter C/N ratio; and (f) the effect of human disturbances. A new Community Structure Diversity index (CSD) was developed and tested. This index is more accurate than other indices in reflecting the true structure of the macroinvertebrate community since it utilizes terms of density, biomass, frequency and species richness. It showed significant correlations with the soil physical-chemical factors which influence the diversity of soil macroinvertebrates. Furthermore, this index showed sensitive diversity values for habitats with similar degrees of taxa richness as it was influenced by land-use practices. Community ordination and trellis diagrams showed that within either the desert or temperate ecosystems, similar land-use practices created similar effects upon soil faunal communities. (Abstract shortened with permission of author.)

Biological sciences

Biology

Ecology

Entomology

Environmental science

Health and environmental sciences

D. L. Dindal

S. H. Shakir

p

[Thesis]

276903

a

Y