Table 1: Main characteristics of the BIOTA observatories included in this study & Table 3: Occurrence of termite taxa at the observatories

Termites are the most important soil ecosystem engineers of semi-arid and arid habitats. They enhance decomposition processes as well as the subsequent mineralisation of nutrients by bacteria and fungi. Through their construction of galleries, nests and mounds, they promote soil turnover and influence the distribution of nutrients and also alter texture and hydrological properties of soils, thereby affecting the heterogeneity of their ecosystem. The main aim of the present thesis was to define the impact of termites on ecosys-tem functioning in a semi-arid ecosystem. In a baseline study, I assessed the diversity of termite taxa in relation to the amount of precipitation, the vegetation patterns and the land use systems at several sites in Namibia. Subsequently, I focussed on a species that is highly abundant in many African savannas, the fungus growing and mound building species Macro-termes michaelseni (Sjöstedt, 1914). I asked how this species influences the spatial hetero-geneity of soil and vegetation patterns. From repeated samplings at 13 sites in Namibia, I obtained 17 termite taxa of 15 genera. While the type of land use seems to have a minor effect on the termite fauna, the mean annual precipitation explained 96% and the Simpson index of vascular plant diversity 81% of the variation in taxa diversity. The number of termite taxa increased with both of these explanation variables. In contrast to former studies on Macrotermes mounds in several regions of Africa that I reviewed, soil analyses from M. michaelseni mounds in the central Namibian savanna revealed that they contain much higher nitrogen contents when compared to their parent material. Further analyses revealed that nitrate forms a major component of the nitrogen content in termite mounds. As nitrate solves easily in water, evaporation processes are most probably responsible for the transport of solved nitrates to the mound surface and their accumulation there. The analysed mounds in central Namibia contained higher sand propor-tions compared to the mounds of the former studies. Through the higher percentage of coarse and middle sized pores, water moves more easily in sandy soils compared to more clayey soils. In consequence, evaporation-driven nitrate accumulation can occur in the studied mounds at high rates. ff...

Characteristics of soil profiles from the Ouémé Upper Catchment (HVO), Térou, Benin

Soil degradation threatens agricultural production and food security in Sub-Saharan Africa. In the coming decades, soil degradation, in particular soil erosion, will become worse through the expansion of agriculture into savannah and forest and changes in climate. This study aims to improve the understanding of how land use and climate change affect the hydrological cycle and soil erosion rates at the catchment scale. We used the semi-distributed, time-continuous erosion model SWAT (Soil Water Assessment Tool) to quantify runoff processes and sheet and rill erosion in the Upper Ouémé River catchment (14500 km**2, Central Benin) for the period 1998-2005. We could then evaluate a range of land use and climate change scenarios with the SWAT model for the period 2001-2050 using spatial data from the land use model CLUE-S and the regional climate model REMO. Field investigations were performed to parameterise a soil map, to measure suspended sediment concentrations for model calibration and validation and to characterise erosion forms, degraded agricultural fields and soil conservation practices. Modelling results reveal current "hotspots" of soil erosion in the north-western, eastern and north-eastern parts of the Upper Ouémé catchment. As a consequence of rapid expansion of agricultural areas triggered by high population growth (partially caused by migration) and resulting increases in surface runoff and topsoil erosion, the mean sediment yield in the Upper Ouémé River outlet is expected to increase by 42 to 95% by 2025, depending on the land use scenario. In contrast, changes in climate variables led to decreases in sediment yield of 5 to 14% in 2001-2025 and 17 to 24% in 2026-2050. Combined scenarios showed the dominance of land use change leading to changes in mean sediment yield of -2 to +31% in 2001-2025. Scenario results vary considerably within the catchment. Current "hotspots" of soil erosion will aggravate, and a new "hotspot" will appear in the southern part of the catchment. Although only small parts of the Upper Ouémé catchment belong to the most degraded zones in the country, sustainable soil and plant management practices should be promoted in the entire catchment. The results of this study can support planning of soil conservation activities in Benin.

USAID reports : A.I.D. support for land reform.

"SR/LR/B-1".

BMB Enterprises Inc. right-of-way request for a hydroelectric generating facility, Deep Creek Mountains, environmental assessment (EA).

Mode of access: Internet.

Black Mountain public land disposal, supplement to Engen Mountain Development Corporation proposed winter sports area environmental assessment (EA), draft planning amendment environmental assessment (EA).

Mode of access: Internet.

City of Ann Arbor, Washtenaw County, Michigan

Map shows size city wards, township sections, lot boundaries, buildings and other cultural features, and sections of land annexed by the city.

Livestock grazing management and water quality protection : (state of the art reference document) /

Mode of access: Internet.

Areas of Critical Environmental Concern /

"BLM CA GI 001 8011."--p. [12]

Revision of title 16, U.S. code, "conservation and reclamation." [Proposed] report to accompany H.R., a bill to revise, codify, and enact into law, title 16, of the United States code, entitled "Conservation and reclamation."

At head of title: Committee print. 83d Cong., 2d sess. House report no.

Sacramento and San Joaquin drainage district refunding act, Reclamation board act and Reclamation board bond act of the state of California, as in effect on and after July 29, 1927, with all amendments to and including those of 1927.

Mode of access: Internet.

Metropolitan America in transition: implications for land use and transportation planning.

Mode of access: Internet.

Orders affecting public lands in Alaska : as of June 30, 1958 /

Issued as a supplement to: Alaska federal land withdrawals and reservations.

Rates and the housing question in London : an argument for the rating of site values /

Reprinted by permission from the final volume of "Life and labour of the people of London."

Report of the special advisers on reclamation and rural development on their investigation of opportunities for reclamation and planned group settlement in the southern states. December 2-13, 1926.

Mode of access: Internet.

Official file of comments received on Alaska Natural Gas Transportation System draft environmental impact statement.

Comments received by U.S. EIS Task force.