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71.
Biodiversity is associated with indicators of soil ecosystem functions over a landscape gradient of agricultural intensification 总被引:1,自引:1,他引:0
Steven W. Culman Anna Young-Mathews Allan D. Hollander Howard Ferris Sara Sánchez-Moreno Anthony T. O’Geen Louise E. Jackson 《Landscape Ecology》2010,25(9):1333-1348
Agricultural intensification has led to dramatic losses in biodiversity over the past several decades. Many studies have shown
the effects of intensification on vegetation or soil communities at field or local scales. However, the functional significance
of biodiversity may only appear at larger spatial and temporal scales, due to exchanges among local ecosystems throughout
a landscape. To examine how patterns of biodiversity loss are reflected at larger spatial scales, plant and soil biodiversity
and associated indicators of ecosystem functions were assessed in riparian areas over a 150 km2 agricultural landscape in the Sacramento Valley of California. Publicly-available GIS data were first used to classify and
select sites over the range of soils, topography and plant community types. Representative sites from the landscape were sampled
for soil physiochemical properties, as well as microbial, nematode, and plant communities. Higher agricultural intensification,
based on field and landscape indices, was negatively correlated with richness and diversity of plant and soil taxa, and was
related to indicators of ecosystem functions, such as increased soil nitrate and phosphorus loading, decreased riparian health
ratings, and lower soil carbon, soil microbial biomass and soil food web structure. Both field- and landscape-scale factors
played important roles in the measured losses. The study area was composed of a wide array of soils, vegetation, and land
management, indicating that the observed trends transcended site-specific conditions. 相似文献
72.
Helen Louise Berry Linda Courtenay Botterill Geoff Cockfield Ning Ding 《Agriculture and Human Values》2016,33(4):929-941
In common with much of the Western world, agrarianism—valuing farmers and agricultural activity as intrinsically worthwhile, noble, and contributing to the strength of the national character—runs through Australian culture and politics. Agrarian sentiments and attitudes have been identified through empirical research and by inference from analysis of political debate, policy content, and studies of media and popular culture. Empirical studies have, however, been largely confined to the US, with little in the way of recent re-evaluations of, or developments from, early work. This paper reports on research that seeks quantitative empirical evidence for the existence of agrarianism in the Australian community and seeks to identify its core characteristics. Using a purpose-designed sub-set of items within a large, omnibus-style survey of regional and rural Australia, we demonstrate that agrarianism exists as a scientifically quantifiable concept identifiable through responses to four key propositions: that Australians should support policies aimed at improving the position of the agricultural industries; that working in agriculture and associated industries brings out the best in people; that agricultural producers make a major contribution to environmental protection and biodiversity conservation; and that the development of agriculture in Australia contributed to the development of the national character. We found very little variation in the degree to which different demographic groupings agree with agrarianism. Older people, farmers, and non-Indigenous Australian-born respondents were among those who were statistically significantly more likely to agree with the defining propositions of agrarianism, but their scores were only very slightly higher than those of other sub-populations in the sample. 相似文献
73.
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75.
FitzGerald L Bennett M Ng J Nicholls P James F Elliot A Slaven M Ryan U 《Veterinary parasitology》2011,175(1-2):160-164
To date Cryptosporidium muris has been identified by microscopy and genotyping in cats in two studies. We report morphological and genetic evidence of a mixed C. muris and C. felis infection in a cat and provide the first histological, immunohistochemical, in situ hybridisation and genetic confirmation of a C. muris infection in the stomach of a cat. The cat suffered persistent diarrhoea after the initial consultation, which remained unresolved, despite several medical interventions. Further studies are required to determine the range, prevalence and clinical impact of Cryptosporidium species infecting cats. 相似文献
76.
Smit Louise Langenhoven Wendy E. Petersen Yolanda 《European journal of plant pathology / European Foundation for Plant Pathology》2021,161(3):565-578
European Journal of Plant Pathology - The formal honeybush tea industry in South Africa is relatively new, and has tremendous growth potential. However, as with other cultivated crops, production... 相似文献
77.
Summary Of 250 isolates ofPhytophthora infestans obtained from Northern Ireland potato crops between 1981 and 1993, only six proved to be of the A2 mating type, the remainder
being A1. The first A2 isolate was obtained from a tuber in 1987. The frequency of A2 isolates from 1987 onwards was 3%, a
lower incidence than has been reported for England and Wales and the Republic of Ireland. There was no association between
phenylamide resistance and mating type. 相似文献
78.
Melony J. Sellars Louise Franz Ralf Joachim Moser 《Journal of the World Aquaculture Society》2023,54(1):167-180
Novel Decapod Iridescent virus (DIV1) infections emerged in mainland China around 2014 and have devastated shrimp aquaculture operations in Chinese coastal provinces. In 2020, DIV1 has spread to Taiwan with devastating results to shrimp and crayfish farms, in addition to being found in wild caught Penaeus monodon from the Indian Ocean. This trend is a major cause for concern and an urgent reminder to expand the tools needed to monitor the spread of DIV1 globally. Here, we describe a set of four different real-time polymerase chain reaction (PCR) assays positioned across the genome of DIV1 to detect the virus in shrimp tissues. All four assays show a wide dynamic range and high analytical sensitivity and specificity. In addition, the newly developed assays show excellent diagnostic sensitivity and specificity in clinical Litopenaeus vannamei samples of North Asian origin. The new molecular toolset will enhance global capabilities to monitor the spread of DIV1 and ultimately be used as an early warning system for farmers and authorities to engage in appropriate risk mitigation strategies. 相似文献
79.
Louise Chavarie Kimberly L. Howland Les N. Harris Mike J. Hansen Colin P. Gallagher William J. Harford William M. Tonn Andrew M. Muir Charles C. Krueger 《Ecology of Freshwater Fish》2019,28(3):485-498
A range of organisms, from plankton to fish, commonly shift their habitat distributions horizontally or vertically due to predation risk. Juvenile lake trout, Salvelinus namaycush, are generally viewed as occupying deep areas of lakes to decrease predation pressure from adults. In contrast, we found that juvenile lake trout from Great Bear Lake, NT, Canada, occupied a variety of habitats and from shallow to deep depths (0–150 m), overlapping with adult lake trout. No evidence occurred for a length depth‐based segregation (e.g., ontogenetic shift). Genetic variation was also similar among juveniles in the different depth zones. However, isotopic niches and C:N ratios among juveniles showed some variability in niche widths and positions for individuals caught from the 51–150 m zone compared to juvenile individuals caught from 0–20 m and 21–50 m zones. The uniformly distributed adult lake trout in Great Bear Lake may evenly distribute predation pressure (including cannibalism) across shallow‐ and deep‐water habitats more than in other lakes. As a result, juveniles may respond to differences in foraging opportunities rather than predation risks. Juvenile lake trout did not appear to conform to the general pattern of juveniles seeking a deep‐water refuge to reduce predation risks. In contrast, juvenile lake trout of Great Bear Lake displayed broad resource use across all depths and habitats. 相似文献
80.