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91.
济宁市南部区域是著名的国家商品粮、优质大蒜、优质稻米和有机蔬菜生产基地,由于土壤有机碳作为农田生态系统中土壤肥力的重要组成成分之一,在土壤改良、作物质量和产量提高等方面都有十分重要的作用,因此,对济宁南部区域耕作层土壤有机碳密度及储量的研究具有十分重要的意义。本文以济宁南部煤田地区作为典型区域,以耕作层土壤(0~20cm)为研究对象,采集了79件耕作层土壤样品,利用元素分析仪测定了土壤样品中有机碳含量。经统计分析发现,各类型土壤有机碳密度介于1.92~4.83kg/m2之间,有机碳密度的加权平均值为4.03kg/m2,高于中国表层土壤有机碳密度的平均值2.97kg/m2;通过壤质类型分类而估算的有机碳总储量为4.57×109 kg,通过土壤利用方式分类而估算的有机碳总储量为4.53×109 kg,二者基本吻合;济宁南部区域耕作层土壤有机碳富集程度受人类活动影响较大,耕作层土壤中氮含量与有机碳的线性相关系数为0.924 9;另外,有机碳富集程度与秸秆返田规模也有着一定的关联。研究结果不仅为研究区今后开展耕作层土壤环境质量评价提供依据,也为区域生态平衡研究奠定了基础。 相似文献
92.
基于AHP法的大盘山国家级自然保护区生态质量评价研究 总被引:2,自引:0,他引:2
大盘山保护区是目前中国唯一以野生药用植物种质资源及其生境为核心保护对象的国家级自然保护区.根据保护区类型和自然保护区生态评价指标体系,以生物多样性保护、景观生态改善、科研教育价值、生态旅游价值作为准则层,选择多样性、稀有性、脆弱性、自然性、典型性、面积适宜性、人类干扰作为评价层指标,运用层次分析法(AHP)进行保护区自然生态评价.评价结果:综合评价指数达0.778 4,说明大盘山保护区目前整体生态质量较好,保护价值较高,属于优先保护区域. 相似文献
93.
94.
田贵全 《中国环境管理干部学院学报》2014,(6):22-24
通过对山东省自然保护区进行研究发现,山东省自然保护区建设与管理虽然在自然保护区建设规模、类型、管护能力和主要保护对象等方面取得了新的成绩,但同时也存在自然保护区多区交叉重叠、资源本底不清、管护压力大与能力不足等新问题。随着国家公园、主体功能区和生态补偿制度的实施,山东省自然保护区建设与管理应深化自然保护区管理体制改革,提升自然保护区建设质量,加强自然保护区基础设施规范化建设。 相似文献
95.
96.
R. Stoks 《Behavioral ecology and sociobiology》1999,47(1-2):70-75
Animals commonly choose between microhabitats that differ in foraging return and mortality hazard. I studied the influence
of autotomy, the amputation of a body part, on the way larvae of the damselfly Lestes sponsa deal with the trade-off between foraging or seeking cover. Survival of Lestes larvae when confronted with the odonate predator Aeshna cyanea was higher in a complex than in a simple microhabitat, indicating that this more complex microhabitat was safer. Within the
simple microhabitat, larvae without lamellae had a higher risk for mortality by predation than larvae with lamellae, showing
a long-term cost of autotomy. When varying the foraging value (food present or absent) and predation risk (encaged predator
or no predator) in the simple microhabitat, larvae with and without lamellae responded differentially to the imposed trade-off.
All larvae spent more time in the simple microhabitat when food was present than when food was absent. Larvae without lamellae,
however, only sporadically left the safe microhabitat, irrespective of the presence of the predator. In contrast, larvae with
lamellae shifted more frequently towards the risky microhabitat than those without lamellae, and more often in the absence
than in the presence of the predator. These decisions affected the foraging rates of the animals. I show for the first time
that refuge use is higher after autotomy and that this is associated with the cost of reduced foraging success. The different
microhabitat preferences for larvae with and without lamellae are consistent with their different vulnerabilities to predation
and demonstrate the importance of intrinsic factors in establishing trade-offs.
Received: 4 June 1999 / Received in revised form: 18 August 1999/ Accepted: 18 August 1999 相似文献
97.
ANDREW T. KNIGHT RICHARD M. COWLING MARK DIFFORD BRUCE M. CAMPBELL 《Conservation biology》2010,24(5):1348-1358
Abstract Spatial prioritization techniques are applied in conservation‐planning initiatives to allocate conservation resources. Although typically they are based on ecological data (e.g., species, habitats, ecological processes), increasingly they also include nonecological data, mostly on the vulnerability of valued features and economic costs of implementation. Nevertheless, the effectiveness of conservation actions implemented through conservation‐planning initiatives is a function of the human and social dimensions of social‐ecological systems, such as stakeholders’ willingness and capacity to participate. We assessed human and social factors hypothesized to define opportunities for implementing effective conservation action by individual land managers (those responsible for making day‐to‐day decisions on land use) and mapped these to schedule implementation of a private land conservation program. We surveyed 48 land managers who owned 301 land parcels in the Makana Municipality of the Eastern Cape province in South Africa. Psychometric statistical and cluster analyses were applied to the interview data so as to map human and social factors of conservation opportunity across a landscape of regional conservation importance. Four groups of landowners were identified, in rank order, for a phased implementation process. Furthermore, using psychometric statistical techniques, we reduced the number of interview questions from 165 to 45, which is a preliminary step toward developing surrogates for human and social factors that can be developed rapidly and complemented with measures of conservation value, vulnerability, and economic cost to more‐effectively schedule conservation actions. This work provides conservation and land management professionals direction on where and how implementation of local‐scale conservation should be undertaken to ensure it is feasible. 相似文献
98.
99.
Fisher最优分割法是用离差平方和来表示同类样本之间的差异程度,通过简便的计算步骤和作图,确定最优分类数,使同类样本间的差异最小,各类别样本间的差异最大,并用F检验法检验最优分类数的合理性。文章根据Fisher最优分割法的理论内涵,研究其应用于酸雨环境监测优化布点的可行性。以漳州市沿海区域监测点为研究实例,用Fisher最优分割法确定最优的分类情况和最优的优化布点方案。结果表明,原布设的9个监测点用Fisher最优分割法优化为3个典型点位,可客观地反映漳州市酸雨控制区的整体污染状况和污染趋势,该方法理论内涵直观、计算简便、重复性好,对环境质量监测有重要的意义。 相似文献
100.
Clint D. Kelly 《Behavioral ecology and sociobiology》2008,62(6):855-871
A long-standing hypothesis in behavioural ecology posits that males with greater resource-holding potential (RHP) control
resource sites deemed more valuable by sexually-receptive females and, thereby, males controlling such sites accrue greater
reproductive success (RS). This hypothesis has historically been investigated using three separate but non-mutually exclusive
relationships (male RHP vs. resource value, resource value vs. male RS and male RHP vs. RS). The relationships between these
three variables are predicted to be strongly positive, however, due to measurement error and biological noise, perfect correlations
(r = 1.0) are rare in biology even for well-established relationships. Moreover, the inaccurate identification of either the
male trait(s) important to RHP or the resource characteristic sought by females will weaken the observed strength of the relationships.
Here, I use meta-analysis to quantitatively describe the general pattern of these relationships in animals. I predict that
the relationships between male RHP, resource-value and RS should be significantly positive (male RHP and resource-value should
explain a large amount of the variation in male RS). My meta-analysis supports this hypothesis; however, in the best case
scenario only ca. 20% of the variation in the response variable was explained. I conclude by identifying areas in which we
need to improve our investigations of resource-defence animals and recommending approaches to meet these needs.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献