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1.
为保证福建省速生丰产林持续优质发展,系统分析了与营造速生丰产林相关的种苗基础和种苗问题,提出了与发展速生丰产林相适应的种苗对策. 相似文献
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Effects of land ownership and landscape-level factors on rare-species richness in natural areas of southern Ontario,Canada 总被引:5,自引:0,他引:5
Lovett-Doust J. Biernacki M. Page R. Chan M. Natgunarajah R. Timis G. 《Landscape Ecology》2003,18(6):621-633
Surprisingly few studies have considered the extent to which the nature of the ownership of land is associated with differences
in biodiversity. We analysed ownership and other landscape-level effects on rare-species richness for both globally- and regionally-rare
biota (including birds, herpetofauna, butterflies, mammals, and plants) in 289 designated natural areas (NAs) in southern
Ontario, Canada. Information about each NA −including area, number of plant communities, ownership status and details of species
diversity were collected from published sources. Length of perimeter of NA, relative isolation, and an estimate of fragmentation
were measured using image analysis and GIS techniques. NAs were in general relatively small, with mean area of 158 ha (median
85 ha, range from 0.9 to 1278 ha) for private NAs; public NAs had mean area of 132 ha (median 16 ha, range from 0.1 to 1481
ha). Mean number of plant communities was 4.6 (median 4, range 1- 13) at private NAs and 3.8 (median 3, range 1-16) at public
NAs. Our results show that, of several landscape-level factors, area had the greatest effects on rare-species richness and
other biotic indices. Effects of area were followed by effects of plant community diversity, however this was itself significantly
affected by area and the extent of perimeter of the NA. Both these factors were followed by effects of ownership of the NA
and by effects of isolation of the NA (represented by minimum distance to nearest NA and by number of NAs in 10 km radius).
Other landscape- level factors did not appear to have overall significant effects. Variation in area accounted for 0.1% to
29% of variation in number of rare species, with lower values for globally-rare, than for regionally-rare taxa. For all biotic
groups, public ownership of NAs was associated with significantly greater rare-species richness compared to private ownership,
even after other factors such as area were controlled. For all globally-rare biota except butterflies, area of NA had greater
effects on rare-species richness than did ownership. Richness of regionally- rare birds was more affected by plant community
diversity than by area of NA. Number of recorded plant communities accounted from 2.1% of variation in number of globally-rare
plant species to as high as 31% of variation in regionally-rare butterflies. The diversity of plant communities was itself
influenced by total site area (accounting for 45% of variation), extent of elongation of the NA, and both external- and interior-
edge perimeters. Public NAs had greatest numbers of rare biota and so should be a significant focus for conservation programs.
Smaller, privately-owned patches of natural area dominate (by number and area) in this densely populated region and their
significance should not be overlooked.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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稻瘿蚊间歇性暴发原因和治理对策探讨 总被引:3,自引:0,他引:3
通过多年的系统调查和观察,明确了稻瘿蚊发生具有间歇性、隐蔽性、暴发性、毁灭性和专一性等5个特点,分析了其在大田县间歇大发生有5个方面的因素。防治上提出农业防治可采取“铲”、“避”、“改”等方法,化学防治应选用具有强触杀、强渗透力药剂,采用毒土法施药技术。 相似文献
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Ecology and non-chemical control of Rumex crispus and R. obtusifolius (Polygonaceae): a review 总被引:1,自引:1,他引:1
J G Zaller 《Weed Research》2004,44(6):414-432
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狼山鸡保种群不同世代MHC BF基因遗传多样性研究 总被引:2,自引:0,他引:2
通过Illumina平台Miseq重测序方法分析不同世代(G0、G5、G10、G12、G14、G15、G17)的MHC BF1和BF2基因座位多态性,揭示狼山鸡不同世代间MHC BF基因遗传多样性,为更好地监测保种效果提供科学的决策依据。在狼山鸡7个世代中分别鉴定出MHC BF1、BF2基因59和34个SNPs。狼山鸡MHC BF1基因观察杂合度(Ho)、期望杂合度(He)和多态信息含量(PIC)在G10、G12、G14保持稳定,Ho在不同世代变化情况为G17G15G14、G12、G10G5G0,He和PIC在不同世代变化情况为G17、G15G14、G12、G10G5G0,MHC BF2基因的Ho在G10、G14、G15保持稳定,其他世代变化情况为G17、G12G15、G14、G10G0、G5;He和PIC在G12、G14、G15和G17保持稳定,在其他世代变化情况为G17、G15、G14、G12G10G5、G0。从本研究结果看,狼山鸡不同世代MHC BF1和BF2遗传多样性变化规律不太一致,但总体规律符合波动选择(时空变换的选择)假说,随着时间的推移MHC BF基因遗传多样性变得更为丰富,在某些连续几个世代群体遗传多样性基本保持稳定,这可能与MHC BF基因功能有关。 相似文献
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本研究利用问卷调查收集了上海动物园游客类型与特征、游园目的、游客游览时获得野生动物科普知识的途径、游客对现有科普活动的评价、对科普教育的需求、游客满意度、意见与建议等,并进行了研究。结果表明,大部分(66.02%)游客为本市居民和暂居本市的中青年。近9成(89.51%)游客携带孩子游览动物园,其中超过半数(52.34%)为父母与孩子共同出行。游客游园目的主要为观看动物、游玩娱乐和让孩子学习动物知识。观察动物和阅读动物科普说明牌是游客学习动物科普知识的主要途径。互动类和深度游类项目,是游客最愿意参加的活动类型。游客更希望园方从动物科普设施、饲养员讲解、志愿者讲解这3方面提升其教育功能。总体而言,游客对上海动物园感到满意,超过半数(53.81%)表示很满意。具体而言,动物说明牌的满意度最高,其次是路面状况和路标指示牌。基于研究结果,提出以下建议:提升科普活动的内涵和互动性;提升游园体验,延长游览时间;寻找迎合和引导的平衡;完善基础设施。 相似文献
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Timo J. Ruokonen Mikko Kiljunen Jaakko Erkinaro Panu Orell Olli Sivonen Eero Vestola Roger I. Jones 《Ecology of Freshwater Fish》2019,28(1):53-61
We estimated the proportions of anadromous and freshwater‐resident brown trout (Salmo trutta) in different parts of the subarctic River Näätämöjoki/Neidenelva system (Finland and Norway) using carbon, nitrogen and hydrogen stable isotope analyses of archived scales as identifiers of migration strategy. Our results showed that carbon stable isotope values were the best predictor of migration strategy. Most individuals fell into two clearly distinct groups representing anadromous (47%) or freshwater‐resident (42%) individuals, but some fish had intermediate carbon values suggesting repeated movement between freshwater and the sea. The proportion of anadromous individuals decreased steadily with distance from the sea forming a spatial continuum in migration strategies which is probably maintained by the combination of several factors such as divergent availability of food resources, variable migration costs and genetic differences. These within‐catchment differences in migration strategies should be taken into account in fisheries management practices. 相似文献