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251.
One hundred forty seven samples of bovine milk were collected from 14 districts of Haryana, India during December 1998–February
1999 and analysed for the presence of organochlorine pesticide (OCPs) residues. ∑HCH, ∑DDT, ∑endosulfan and aldrin were detected
in 100%, 97%, 43% and 12% samples and with mean values of 0.0292, 0.0367, 0.0022 and 0.0036 μg/ml, respectively. Eight percent
samples exceeded the maximum residue limit (MRL) of 0.10 mg/kg as recommended by WHO for ∑HCH, 4% samples of 0.05 mg/kg for
α-HCH, 5% samples of 0.01 mg/kg for γ-HCH, 26% samples of 0.02 mg/kg for β-HCH as recommended by PFAA and 24% samples of 0.05 mg/kg
as recommended by FAO for ∑DDT. Concentrations of β-HCH and p,p′-DDE were more as compared to other isomers and metabolites
of HCH and DDT. 相似文献
252.
253.
Assessing the Geographic Representativeness of Genebank Collections: the Case of Bolivian Wild Potatoes 总被引:5,自引:0,他引:5
R. J. Hijmans K. A. Garrett Z. Huamán D. P. Zhang M. Schreuder M. Bonierbale 《Conservation biology》2000,14(6):1755-1765
Abstract: Genebank collection databases can be used for ecogeographical studies under the assumption that the accessions are a geographically unbiased sample. We evaluated the representativeness of a collection of wild potatoes from Bolivia and defined and assessed four types of bias: species, species-area, hotspot, and infrastructure. Species bias is the sampling of some species more often than others. Species-area bias is a sampling that is disproportionate to the total area in which a species is found. Hotspot bias is the disproportionate sampling of areas with high levels of diversity. Infrastructure bias is the disproportionate sampling of areas near roads and towns. Each of these biases is present in the Bolivian wild potato collection. The infrastructure bias was strong: 60% of all wild potato accessions were collected within 2 km of a road, as opposed to 22%, if collections had been made randomly. This analysis can serve as a guide for future collecting trips. It can also provide baseline information for the application of genebank data in studies based on geographic information systems. 相似文献
254.
Conservation Genetics at the Species Boundary 总被引:13,自引:0,他引:13
Paul Z. Goldstein§ Robert Desalle George Amato † and Alfried P. Vogler‡ 《Conservation biology》2000,14(1):120-131
Abstract: Conservation genetics has expanded its purview such that molecular techniques are now used routinely to prioritize populations for listing and protection and infer their historical relationships in addition to addressing more traditional questions of heterozygosity and inbreeding depression. Failure to specify whether molecular data are being used for diagnosis-related questions or for population viability questions, however, can lead either to misinterpretation of character data as adaptive information or to misinterpretation of frequency or distance data as diagnostic or historical information. Each of these misinterpretations will confound conservation programs. The character-based approach to delimiting phylogenetic species is both operationally and logically superior to "diagnostic" methods that involve distance- or frequency-based routines, which are unstable over time. Tree-based criteria for the diagnosis of conservation "units" are also inappropriate because they can depend on patterns inferred without reference to diagnostic characters. Intraspecific studies, conservation-related or otherwise, that adopt terminology and methods designed to infer nested hierarchic relationships confuse diagnosis with historical inferences by treating diagnoses as outcomes rather than as precursors to phylogeny reconstruction. A character-based diagnostic approach recognizes the analytical dichotomy between species hierarchies and population statistics and provides a framework for the understanding of each. No species concept, however, should be viewed as an absolute criterion for protecting populations, but as part of a framework from within which identification of protection and management goals can be achieved effectively and defensibly. 相似文献
255.
B. Miller # R. Reading J. Hoogland † T. Clark ‡ G. Ceballos § R. List S. Forrest †† L. Hanebury ‡‡ P. Manzano § J. Pacheco § and D. Uresk§§ 《Conservation biology》2000,14(1):318-321
256.
Summary. Using Porapak Q traps, we collected the bark volatiles of six angiosperm trees native to British Columbia: black cottonwood,
Populus trichocarpa Torr. & A. Gray (Salicaceae), trembling aspen, P. tremuloides Michx. (Salicaceae), paper birch, Betula papyrifera Marsh. (Betulaceae), bigleaf maple, Acer macrophyllum Pursh (Aceraceae), red alder, Alnus rubra Bong. (Betulaceae), and Sitka alder, A. viridis ssp. sinuata (Regel) á. L?ve & D. L?ve (Betulaceae). Utilising coupled gas chromatographic-electroantennographic detection analysis, the
captured volatiles were assayed for antennal responses in five species of coniferophagous bark beetles (Coleoptera: Scolytidae),
sympatric with most or all of the angiosperm trees: the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, the mountain pine beetle, D. ponderosae Hopkins, the spruce beetle, D. rufipennis (Kirby), the western balsam bark beetle, Dryocoetes confusus Swaine, and the pine engraver, Ips pini (Say). The identities of 25 antennally-active compounds were determined by coupled gas chromatographic-mass spectroscopic
analysis, and co-chromatographic comparisons with authentic chemicals. The compounds identified were: hexanal, (E)-2-hexenal, (Z)-3-hexen-1-ol, 1-hexanol, heptanal, α-pinene, frontalin, benzaldehyde, β-pinene, 2-hydroxycyclohexanone, 3-carene, limonene,
β-phellandrene, benzyl alcohol, (E)-ocimene, salicylaldehyde, conophthorin, guaiacol, nonanal, methyl salicylate, 4-allylanisole, decanal, thymol methyl ether,
(E)-nerolidol, and dendrolasin. A number of these compounds are known semiochemicals that are active in the behaviour of other
organisms, including bark beetles, suggesting a high degree of semiochemical parsimony. Antennally-active compounds ranged
from seven in A. viridis to 17 in P. trichocarpa. The fewest number of compounds (9) were detected by I. pini and the largest number (24) were detected by D. pseudotsugae. Six compounds excited the antennae of all five species of bark beetles. The large number of antennally-active compounds
detected in common by numerous bark beetles and present in common in numerous nonhost trees supports the hypothesis of olfaction-based
recognition and avoidance of nonhost angiosperm trees during the process of host selection by coniferophagous bark beetles.
Received 13 December 1999; accepted 14 March 2000 相似文献
257.
近20-30年来,很多国家引进了综合性环境保护法律.然而,人们逐渐认识到,在进行具体技术调控的同时,也需要意识上和管理原则上的改变.为帮助各公司在公司层次上减少、评估、监测和控制环境影响,已经开发了各种环境管理技术.本文根据对丹麦公司的一次调查,论述了下列问题:这些技术是如何在工业中采用的?以及发生态度上的变化了吗? 相似文献
258.
F. Maltagliati A. P. Peru M. Casu F. Rossi C. Lardicci M. Curini-Galletti A. Castelli 《Marine Biology》2000,136(5):871-879
The genetic relationships between morphologically indistinguishable marine and brackish populations of Syllis gracilis Grube, 1840 (Polychaeta: Syllidae) were studied by means of allozyme electrophoresis. Samples of S. gracilis from marine coastal and brackish-water habitats were examined for variation at 13 presumptive loci. In addition, a sample
of the closely related species S. prolifera (Krohn, 1852) was analysed. Five loci were multiallelic in at least one population of S. gracilis and eight loci in S. prolifera. Low to moderate levels of within-population genetic variability were found, with average expected heterozygosity values
ranging from H = 0.068 (±0.043 SE) to 0.187 (±0.069 SE) in the populations of S. gracilis; higher values were found in S. prolifera (H = 0.325 ± 0.076). The presence of various private alleles indicated a marked genetic divergence among populations of S. gracilis, with Nei's genetic distances ranging from D = 0.000 to 0.833 and a highly significant F
ST value. Furthermore, evidence for strong genetic heterogeneity between two sympatric marine populations was found. UPGMA cluster
analysis and multidimensional scaling pointed out a clear genetic divergence between brackish and marine populations. At least
two genetically divergent entities occurred in marine and brackish habitats. This could be due to local adaptation of individuals
coming from marine populations to brackish habitats, but more presumably to the occurrence of a species complex within S. gracilis.
Received: 6 June 1999 / Accepted: 7 February 2000 相似文献
259.
260.
The endemic New Zealand echinoid, Evechinus chloroticus (Valenciennes), was sampled approximately monthly from September 1990 to October 1994 at three sites in Tory Channel, Marlborough
Sounds, New Zealand. These channel sites (outer, mid and inner) were up to 20 km from the open ocean and differed in their
shore type, exposure to wave action and macrophyte abundance. E. chloroticus showed an annual reproductive cycle at each site, with gametogenesis commencing in the late austral winter and spawning in
summer. Maximum gonad indices (reproductive potential) varied spatially, with the outer site generally having higher maximum
gonad indices than the inner site, and temporally, with maximum gonad indices occurring earlier in 3 of the 4 seasons at the
outer site than the inner site. The mid and inner sites showed much greater variation in maximum gonad indices (range 15.83
to 26.99% and 11.87 to 20.90%, respectively) than the outer site (range 19.31 to 22.95%). Reproductive output (weight of gametes
released per gram echinoid) also varied, with the different sites showing significantly different outputs in the different
years. A regression of maximum reproductive potential against reproductive output was significant ( p < 0.001), and had a positive slope with an r
2 of 0.79. While, the initiation of gametogenesis was relatively synchronous between sites and years, and is possibly cued
by increasing daylength, it progressed at different rates among populations. Spawning did show spatial and temporal variability,
occurring near the time of highest sea-surface temperatures (∼15 °C). The observed variations in reproductive cycle may be
related to small-scale variability in diet and environmental conditions. Furthermore, asynchronous spawning, variable spawning
duration, and variable reproductive output are likely to strongly influence annual recruitment variability in E. chloroticus, with different larval subpopulations contributing unequally in different years. The ecological consequences of this, both
for the ability of E. chloroticus to propagate itself in space and time and for the management of the developing E. chloroticus fishery in New Zealand, are discussed.
Received: 9 December 1998 / Accepted: 13 June 2000 相似文献