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31.
Effects of cattle grazing and haying on wildlife conservation at National Wildlife Refuges in the United States 总被引:1,自引:0,他引:1
Beverly I. Strassmann 《Environmental management》1987,11(1):35-44
The National Wildlife Refuge System is perhaps the most important system of federal lands for protecting wildlife in the United States. Only at refuges has wildlife conservation been legislated to have higher priority than either recreational or commercial activities. Presently, private ranchers and farmers graze cattle on 981,954 ha and harvest hay on 12,021 ha at 123 National Wildlife Refuges. US Fish and Wildlife Service policy is to permit these uses primarily when needed to benefit refuge wildlife. To evaluate the success of this policy, I surveyed grassland management practices at the 123 refuges. The survey results indicate that in fiscal year 1980 there were 374,849 animal unit months (AUMs) of cattle grazing, or 41% more than was reported by the Fish and Wildlife Service. According to managers' opinions, 86 species of wildlife are positively affected and 82 are negatively affected by refuge cattle grazing or haying. However, quantitative field studies of the effect of cattle grazing and haying on wildlife coupled with the survey data on how refuge programs are implemented suggest that these activities are impeding the goal of wildlife conservation. Particular management problems uncovered by the survey include overgrazing of riparian habitats, wildlife mortality due to collisions with cattle fences, and mowing of migratory bird habitat during the breeding season. Managers reported that they spend $919,740 administering cattle grazing and haying; thus refuge grazing and haying programs are also expensive. At any single refuge these uses occupy up to 50% of refuge funds and 55% of staff time. In light of these results, prescribed burning may be a better wildlife management option than is either cattle grazing or haying. 相似文献
32.
Woo-Jung Choi Gwang-Hyun Han Sang-Mo Lee Goon-Taek Lee Kwang-Sik Yoon Soo-Myung Choi Hee-Myong Ro 《Agriculture, ecosystems & environment》2007,120(2-4):259-268
An understanding of the long-term changes in the nitrate contamination pattern of unconfined groundwater is critical to conservation of drinking water in rural areas supporting mixed land-use activities such as cropping, livestock farming, and residence. To examine the effect of different land-use activities on nitrate contamination, groundwater samples were collected monthly for 3 years (1997–1999) from 12 wells in rural areas with different land-use activities and analyzed for the concentrations and N isotopic ratios (δ15N) of nitrate. The characteristics of nitrate contamination clearly differed with land-use activities. The percentages of samples that had a nitrate concentration exceeding the national standard for drinking water (10 mg N L−1) were 0, 23, 43, and 67% for the uncontaminated natural area, cropping area, cropping-livestock farming complex area, and residential area, respectively. The range of δ15N values was between +1.4 and +4.5‰ for groundwater nitrate from the uncontaminated natural area. In the cropping area, the δ15N values were slightly different with the type of fertilizer applied to fields in the vicinity of the well, and the values ranged between +8.7 and +14.4‰ for the compost-applied area and between +4.5 and +8.5‰ for the area where urea was applied with compost. The δ15N values of the cropping-livestock farming complex area ranged from +1.0 to +17.7‰, probably resulting from mixed contamination sources (inorganic fertilizer and livestock manure). The well located closest to the livestock feedlot had relatively higher δ15N values, with a range between +8.7 and +17.6‰. In the residential area, a higher δ15N (most frequently above +10‰) of nitrate suggested that the major source of contamination was effluent from leaky septic tanks. Our data showed that unconfined groundwater is susceptible to land-use activities above the aquifers, and the impacts of the activities could be more precisely inferred from long-term data on the concentration and δ15N of nitrate. By determining the impacts, more effective (specific to contamination sources) measures for preventing groundwater quality could be implemented. 相似文献
33.
This paper introduces a new portable intelligent electronic nose system developed especially for measuring and analysing livestock
and poultry farm odours. It can be used in both laboratory and field. The sensor array of the proposed electronic nose consists
of 14 gas sensors, a humidity sensor, and a temperature sensor. The gas sensors were especially selected for the main compounds
from the livestock farm odours. An expert system called “Odour Expert” was developed to support researchers’ and farmers’
decision making on odour control strategies for livestock and poultry operations. “Odour Expert” utilises several advanced
artificial intelligence technologies tailored to livestock and poultry farm odours. It can provide more advanced odour analysis
than existing commercially available products. In addition, a rank of odour generation factors is provided, which refines
the focus of odour control research. Field experiments were conducted downwind from the barns on 14 livestock and poultry
farms. Experimental results show that the predicted odour strengths by the electronic nose yield higher consistency in comparison
to the perceived odour intensity by human panel. The “Odour Expert” is a useful tool for assisting farmers’ odour management
practises.
Supported by Ontario Pork, Natural Sciences and Engineering Research Council (NSERC), and Ontario Ministry of Agriculture
and Food (OMAF) of Canada. 相似文献
34.
35.
V. K. Garg Y. K. Yadav Aleenjeet Sheoran Subhash Chand Priya Kaushik 《The Environmentalist》2006,26(4):269-276
In India, millions of tones of livestock excreta are produced. Our study explores the potential of an epigeic earthworm Eisenia foetida to compost different livestock excreta (cow, buffalo, horse, donkey, sheep, goat and camel) into value added product (vermicompost)
at the laboratory scale. Vermicomposting resulted in lowering of pH, electrical conductivity, potassium and C:N ratio and
increase in nitrogen and phosphorus contents. Total K was lower in the final cast than in the initial feed. C:N ratios of
the vermicomposts ranged from 16.2 ± 2.17 to 75.4 ± 6.84. Microbial activity measured as dehydrogenase activity in buffalo,
donkey and camel wastes increased with time up to day 90. But in sheep and goat wastes, maximum dehydrogenase activity was
recorded on day 60 and decreased thereafter. The cocoons and hatchlings production by Eisenia foetida in different excreta were also investigated. The greatest number and biomass of hatchlings was recorded in horse excreta
followed by cow, goat and sheep excreta. Thus, cow, horse, sheep and goat excreta show potential as good substrates in vermicomposting
using Eisenia foetida, although further research is required to explore the feasibility of use of buffalo, donkey and camel excreta in combination
with cow/sheep/goat excreta. 相似文献
36.
The effects of livestock grazing on selected riparian and stream attributes, water chemistry, and algal biomass were investigated
over a two-year period using livestock enclosures and by completing stream surveys in the Cypress Hills grassland plateau,
Alberta, Canada. Livestock enclosure experiments, partially replicated in three streams, comprised four treatments: (1) early
season livestock grazing (June–August), (2) late season livestock grazing (August–September), (3) all season grazing (June–September),
and (4) livestock absent controls. Livestock grazing significantly decreased streambank stability, biomass of riparian vegetation,
and the extent to which aquatic vegetation covered the stream channels compared with livestock-absent controls. Water quality
comparisons indicated significant differences among the four livestock grazing treatments in Battle and Graburn creeks but
not in Nine Mile Creek. In Graburn Creek, the concentration of total phosphorus in the all-season livestock grazing treatment
was significantly higher than that in the livestock-absent control, and the early season and late season grazing treatments.
Concentrations of soluble reactive phosphorus in the all-season livestock grazing treatment also exceeded that in livestock-absent
control. In contrast, differences in water quality variables in the remaining 22 comparisons (i.e., 22 of the total 24 comparisons)
were minor even when differences were statistically significant. Effects of livestock grazing on algal biomass were variable,
and there was no consistent pattern among creeks. At the watershed scale, spatial variation in algal biomass was related (P < 0.05) with concentrations of NO2
− + NO3
− and soluble reactive phosphorus in two of the four study creeks. Nutrient diffusing substrata experiments showed that algal
communities were either nitrogen-limited or not limited by nutrients, depending on stream and season. 相似文献
37.
为了解辽阳市蔬菜种植和畜禽养殖基地土壤中重金属状况,依据《环境监测分析方法》、《土壤元素的近代分析方法》的要求土壤采样分析。并根据土壤环境质量标准(GB15618-1995),采用Harkanson"潜在生态危害指数法"对土壤中重金属进行生态风险评价。结果表明,在蔬菜种植和畜禽养殖基地所选典型采样点中,重金属含量无超标现象,均属安全范围,对人体及生物无危害。 相似文献
38.
The number of environmental impact assessment (EIA) screenings in Denmark has increased dramatically since 2000. This is a consequence of increased pig production as well as the concentration of production on larger farms. In the same period, EIA rules have developed primarily due to an increased focus on the protection of groundwater and Natura 2000 sites. In particular, the implementation of Natura 2000 in Danish legislation has increased the demands on many farms. In its rulings on appealed cases, the Nature Protection Board of Appeal has strengthened its demands, and this is mirrored in screening practices. In this paper, the demands formulated in the guidelines of local authorities were analysed in order to investigate how the protection of groundwater, coastal waters, lakes and Natura 2000 sites develops through EIA screening. It is concluded that the level of protection has improved, and that the main cause for this is not EIA regulations as such, but the positive role which the implementation of the Natura 2000 objectives has played in this development. However, it was also found that the formulation of demands varies greatly between the counties, thus often resulting in ambiguity and leaving room for quite different practices in different counties. 相似文献
39.
通过静态(10 d)和动态(105 d)两个阶段成功启动自行设计的亚硝化-厌氧氨氧化一体化反应器,并进行了处理禽畜养殖场废水的研究。反应器运行稳定后,分别考察了溶解氧(DO)和水力停留时间(HRT)对一体化反应器运行性能的影响。结果表明,当供氧段DO为1.5 mg/L~2.0 mg/L以及HRT在22 h~26 h时,反应器运行效果良好;采用一体化反应器在常温18℃~30℃,供氧段DO为1.5 mg/L~2.0 mg/L,废水HRT约24h条件下处理某禽畜养殖场厌氧池出水,COD、NH4^+-N和TN平均去除率分别为75.10%、85.77%、69.28%,脱氮效果明显,反应器氮容积负荷达0.14 kg/m^3.d。 相似文献
40.