Environmental Effects of Conservation Practices on Grazing Lands Diversity (BIOLOG Ecoplates) As a Reliable Tool for 796
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Rangeland: Fish and Wildlife Effects 790. Willow flycatcher and yellow warbler response to cattle grazing. Taylor, D. M. and Littlefield, C. D. American Birds 40(5): 1169-1173. (1986) NAL Call #: QL671.A32; ISSN: 0004-7686 Descriptors: Empidonax traillii/ Dendroica petechia/ human activity/ habitat protection © The Thomson Corporation Plant Ecology, Biodiversity, and Other Environmental Effects 791. 14 vs. 42-paddock rotational grazing aboveground abandonment/ land degradation/ mountain grazing lands: biomass dynamics forage production and harvest area enclosures, open management schemes/ soil efficiency. properties/ species richness/ vegetation composition Heitschmidt, R. K.; Dowhower, S. L.; and Walker, J. W. Abstract: Loss of biodiversity is the single most important Journal of Range Management 40(3): 216-223. (1987) threat to the conservation and sustainable use of drylands NAL Call #: 60.18 J82; ISSN: 0022-409X in northern Ethiopia due to many centuries of cultivation http://jrm.library.arizona.edu/data/1987/403/6heit.pdf and heavy livestock grazing pressure. The current study Descriptors: cattle/ Texas/ USA/ stocking densities/ assessed the restoration of biodiversity in highly degraded growing season areas in eastern Tigray, northern Ethiopia using area Abstract: Research was initiated at the Texas Experimental enclosures (AEs). The study assessed whether the Ranch in 1981 to quantify the effects of 2 stocking differences in biodiversity between AEs and open densities, equivalent to 14- and 42-paddock rotational management schemes and time of land abandonment grazing (RG) treatments, on aboveground biomass influenced diversity of plant life forms (i.e. herbs, shrubs dynamics, aboveground net primary production (ANPP), and trees). Changes in biodiversity were compared using and harvest efficiency of forage. Baseline data were the state-and-transition model. Management types and time collected in 1981 from 3 adjacent 30-ha paddocks in a 14- since abandonment (hereafter called age) had a significant paddock, cell designed RG treatment. Near the beginning effect on herbaceous plant species abundance but not in of the 1982 growing season the center paddock was shrub species, while site factors had a greater effect on subdivided into three, 10-ha paddocks to establish the RG- diversity of plant life forms in general. Herbaceous species 42 treatment. Stocking densities in the 14- and 42-paddock richness increased with age of restoration, reaching a treatments were 4.2 and 12.5 AU/ha, respectively, from maximum after three years of rest and declined thereafter, March 1982 to June 1984 and 3.0 and 9.1 AU/ha from June most probably as a result of hay harvesting and to November 1984. During 1981, estimated ANPP in the replacement of annual species by perennial grass species. two RG-14 paddocks averaged 4,088 kg/ha as compared to Tree species richness increased gradually with age of land 5,762 in the single RG-42 paddock. Following subdivision, abandonment up to the maximum age of eight years. Four ANPP in the RG-14 paddocks averaged 2,533 kg/ha as vegetation states and seven possible transitions that could compared to 2,670 kg/ha in the RG-42 paddocks. Although guide management were identified. The vegetation states ANPP varied significantly among the 4 years of the study it differed in terms of diversity of herbs and tree species but was not affected by density treatment. Likewise, harvest not those of shrubs. Promotion of tree species states will efficiency varied among years but was unaffected by require longer periods of rest, while promotion of density treatment. Average harvest efficiency over the 4 herbaceous species richness will need shorter periods. The years was about 42%. Aboveground biomass dynamics state-and-transitional model could, therefore, be used to were also generally unaffected by density treatments. guide future management by promoting vegetation states © The Thomson Corporation that are desired by land users. © The Thomson Corporation 792. Alfalfa survival and vigor in rangeland grazed by sheep. 794. Bacteria as bioindicators in wetlands: Berdahl, J. D.; Wilton, A. C.; Lorenz, R. J.; and Frank, A. B. Bioassessment in the Bonneville Basin of Utah, USA. Journal of Range Management 39(1): 59-62. (1986) Merkley, M.; Rader, R. B.; Mcarthur, J. V.; and Eggett, D. NAL Call #: 60.18 J82; ISSN: 0022-409X Wetlands 24(3): 600-607. (2004) http://jrm.library.arizona.edu/data/1986/391/15berd.pdf NAL Call #: QH75.A1W47; ISSN: 0277-5212 Descriptors: Medicago/ cultivars/ germplasm/ grazing/ Descriptors: marshes/ wetlands/ basins/ biodegradation/ regrowth/ sheep/ rangelands/ North Dakota genetic analysis/ indicator species/ grazing/ surface area/ This citation is from AGRICOLA. comparative studies/ analytical techniques/ genetics/ bioassays/ degradation/ man-induced effects/ 793. An assessment of restoration of biodiversity in anthropogenic factors/ genetic diversity/ species diversity/ degraded high mountain grazing lands in northern bacteria/ biodiversity/ organic compounds/ substrates/ Ethiopia. ecosystems/ bioindicators/ USA, Utah, Bonneville Basin Asefa, D. T.; Oba, G.; Weladji, R. B.; and Colman, J. E. Abstract: Bacteria should be excellent indicators of the Land Degradation and Development 14(1): 25-38. (2003) early signs of degradation caused by human intervention NAL Call #: S622.L26; ISSN: 1085-3278 because they have the highest surface area to volume ratio Descriptors: state and transition model: mathematical and of all organisms. We determined the utility of a simple computer techniques/ biodiversity restoration/ land procedure that measures aerobic bacterial metabolic 209 Environmental Effects of Conservation Practices on Grazing Lands diversity (BIOLOG EcoPlates) as a reliable tool for 796. Benefits of protective fencing to plant and rodent assessing the effects of cattle grazing on spring communities of the Western Mojave Desert, California. ecosystems of the Bonneville Basin, Utah, USA. Marshes Brooks, Matthew L. disturbed by cattle could be distinguished from protected Environmental Management 19(1): 65-74. (1995) marshes using EcoPlate analyses. The diversity of organic NAL Call #: HC79.E5E5; ISSN: 0364-152X compounds used by bacteria was greater in grazed versus Descriptors: alien grass/ annual plant biomass/ community ungrazed marshes. A separate genetic analysis (DGGE) diversity/ desert ecosystem/ desert tortoise research natural provided corroborating evidence. Greater metabolic area/ forb biomass/ human disturbance/ Kern County/ diversity (EcoPlates) corresponded to greater bacterial livestock grazing/ Merriami's kangaroo rat/ method/ assemblage diversity in grazed versus protected marshes. protective effect Greater plant diversity at grazed sites might account for the Abstract: Human disturbance in the western Mojave Desert greater diversity of organic substrates used by bacteria in takes many forms. The most pervasive are livestock grazed sites. However, the results were not conclusive. In grazing and off-highway vehicle use. Over the past few some marshes, a greater diversity of organic substrate use decades several areas within this region have been fenced occurred where there was greater plant diversity, whereas to preclude human disturbance. These areas provide in other marshes the diversity of organic substrates used by opportunities to study the impact of human activities in a bacteria was lower where plant diversity was greatest. desert ecosystem. This paper documents the response of Regardless of the mechanism, aerobic bacterial metabolic plant and small mammal populations to fencing constructed diversity (EcoPlates) is a potentially valuable tool for between 1978 and 1979 at the Desert Tortoise Research assessing the early signs of degradation in wetland Natural Area, Kern County, California. Aboveground live ecosystems. annual plant biomass was generally greater inside than © CSA outside the fenced plots during April 1990, 1991, and 1992. The alien grass Schismus barbatus was a notable 795. Below-ground biomass and productivity of a exception, producing more biomass in the unprotected grazed site and a neighbouring ungrazed exclosure in a area. Forb biomass was greater than that of alien annual grassland in central Argentina. grasses inside the fence during all three years of the study. Pucheta, Eduardo; Bonamici, Ivano; Cabido, Marcelo; and Outside the fence, forb biomass was significantly higher Diaz, Sandra than that of alien grasses only during spring 1992. Percent Austral Ecology 29(2): 201-208. (2004) cover of perennial shrubs was higher inside the fence than NAL Call #: QH540 .A8; ISSN: 1442-9985 outside, while no significant trend was detected in density. Descriptors: long term exclosure: applied and field There was also more seed biomass inside the fence; this techniques/ below ground biomass/ below ground net plant may have contributed to the greater diversity and density of productivity [bnpp]/ climates/ grazing impact/ mountain Merriam's kangaroo rats (Dipodomys merriami), long-tailed grasslands/ root turnover rates/ seasonal variation pocket mice (Chaetodipus formosus), and southern Abstract: We estimated the below-ground net plant grasshopper mice (Onychomys torridus) in the protected productivity (BNPP) of different biomass components in an area. These results show that protection from human intensively and continuously 45-ha grazed site and in a disturbance has many benefits, including greater overall neighbouring exclosure ungrazed for 16 years for a natural community