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51.
52.
大围山国家级自然保护区是云南省最重要的保护区之一,生物多样性的管理十分重要。研究对生物多样性和影响生物多样性的因子进行评估。研究所采用的第一手自然和生物多样性的第一手数据,如海拔、土壤类型、坡度、森林覆盖率、植物物种、鸟类物种等从大围山保护区的28个样点中获得。用CurveExpert统计软件对这些数据进行数理统计分析,分析的结果显示鸟类物种的多样性与植物物种的多样性呈明显的正相关,说明生境对动物区系多样性保护的关键作用。该研究还分析了关键景观特征与生物多样性的相关性,并对如何测度生物多样性和增强保护和管理该区域的生物多样性提出了建议。本研究的结果不仅对大围山自然保护区的生物多样性保护和管理策略的制定有重要的意义,而且对中国其他自然保护区的保护和管理也有积极地作用。 相似文献
53.
巨桉无性系生长早期选择 总被引:1,自引:0,他引:1
对26个巨桉无性系人工林生长性状的调查分析表明:胸径、材积在无性系间呈极显著差异,相关性分析结果表明胸径、树高、材积三者间存在极显著的正相关关系。变异系数最大的是材积,达到78.82%,其次为树高和胸径,分别为52.23%、23.13%。胸径、树高、材积的重复力分别为0.5744、0.5469、0.3453。利用综合评定方法评选出5个优良的巨桉无性系,分别为20、18、25、9和5号。5个优良无性系胸径、树高、材积的遗传增益分别为11.60%、11.09%和2.05%。 相似文献
54.
After investigating and studying the vegetation, we have established that Makehe Forest, in Sanjiangyuan Nature Reserve, Qinghai
Province, is host to a total of 364 different species, representing 173 “genera” in 55 different vegetative families. We propose
five quantifiable indices for evaluating the level of threat to these plants: 1) the distribution frequency of the “line transect”;
2) the distribution frequency of sample plots; 3) the distribution density inside sample plots; 4) the existing abundance
in the forest region; and 5) plant fidelity. The results show that there are two endangered species, six vulnerable species,
12 nearly threatened species and 344 safe species. The study tried to evaluate the urgency for conserving these plants, according
to coefficients of closeness to disappearance, of genetic loss and of usefulness. Results also showed that the number of species
of primary concern is two; of secondary concern, nine; of the third level, 23; and of least concern, 330 species.
__________
Translated from Journal of Beijing Forestry University, 2006, 28(3): 20–25 [译自: 北京林业大学学报] 相似文献
55.
Kasper Johansen Stuart Phinn Ian Dixon Michael Douglas John Lowry 《Forest Ecology and Management》2007,240(1-3):42-60
Suitable methods for measuring and monitoring the condition of riparian environments are being investigated by government agencies responsible for maintaining these environments in Australia. The objective of this work was to compare two riparian condition assessment approaches, the Tropical Rapid Appraisal of Riparian Condition (TRARC) method developed for rapid on-ground assessment of the environmental condition of savanna riparian zones and an image based riparian condition monitoring scheme. Measurements derived from these two approaches were compared and correlated. The sample representativeness of the TRARC method was evaluated and the cost-effectiveness and suitability for multi-temporal analysis of the two approaches were assessed. Two high spatial resolution multi-spectral QuickBird satellite images captured in 2004 and 2005 and coincident field data covering sections of the Daly River in the Northern Territory, Australia were used in this work. Both field and image data were processed to map indicators of riparian zone condition including percentage canopy cover, organic litter on the ground, canopy continuity, tree clearing, bank stability, and flood damage. Spectral vegetation indices, image segmentation, and supervised classification were used to produce riparian health indicator maps. QuickBird image data were used to examine if the spatial distribution of TRARC transects provided a representative sample of ground based estimates of riparian health indicators. Covering approximately 3% of the study area, the sample mean of the TRARC estimates of individual indicators of riparian zone condition were in most cases within 20% of the global mean derived from the whole imaged riparian area. The cost-effectiveness of the image based approach was compared to that of the ground based TRARC method. Results showed that the TRARC method was more cost-effective at spatial scales from 1 km to 200 km of river in relatively homogeneous riparian zones along rivers with only one channel, while image based assessment becomes more feasible at regional scales (200–2000 km of river). A change detection analysis demonstrated that image data can provide detailed information on gradual change, while the TRARC method is less suited for multi-temporal analysis due to the ranked data format, which inhibits precise detection of change. However, results from both methods were considered to complement each other for single date assessment of riparian zones if used at appropriate spatial scales. 相似文献
56.
57.
H.M.P.J.B. van Rheenen Rene G.A. Boot Marinus J.A. Werger Miguel Ulloa Ulloa 《Forest Ecology and Management》2004,200(1-3):39-48
For sustainable forest management, it is important to know the response of timber species to the change in environment caused by logging. We performed a 2-year study on germination, survival and growth of four timber species, Cedrela odorata, Swietenia macrophylla, Hymenaea courbaril, and Cariniana micrantha, and one non-commercial species Tachigali vasquezii. We sowed seeds of these species in five microenvironments: log landing, gap-crown and gap-trunk, skidder trail and understory, in a tropical lowland moist rain forest in northern Bolivia. We related seed and seedling performance to light availability, soil compaction, and plant competition. Germination did not differ significantly between microenvironments but survival of germinated seeds for most species was significantly higher (P < 0.05) in the log landing (46–100%) than in the understory (0–7%). After 2 years, the tallest plants were always found in the log landing (119–190 cm) and the smallest in the understory (12–26 cm) caused by a higher relative height growth rate (RHGR) in the log landing (0.003–0.004 cm cm−1 per day) compared to the understory (0.000–0.001 cm cm−1 per day). During the first year RHGR was positively related to canopy openness for all species and negatively to the number of overtopping competitors for three species. During the second year also water infiltration explained observed variation to RHGR. These results show that abandoned log landings and logging gaps are suitable environments for the regeneration of timber species studied. This finding suggests that the removal of competitors in log landings and logging gaps combined with leaving seed trees near these microenvironments or sowing seeds, will improve regeneration of timber species in tropical forests. 相似文献
58.
59.
通过对建立自然保护区有效管理考核评估制度的必要性、实践意义和可行性分析,阐述了自然保护区有效管理考核评估制度的基本框架,探讨了该制度实际运作的具体方式,以期促进自然保护区形成以考核与评估为核心的激励机制,切实提高有效管理水平。 相似文献
60.
利用生物地理统计学的原理和方法研究鞭角华扁叶蜂滞育幼虫的虫口密度与其所处的空间位置之间的关系,创建了鞭角华扁叶蜂滞育幼虫虫口密度的半方差函数模型.在此基础上,用不同空间位置上的已知种群密度观测值估计其他空间位置上的未知种群密度,取得了令人满意的估计效果。 相似文献