首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 8 毫秒
1.
Complementarity-based reserve selection algorithms efficiently prioritize sites for biodiversity conservation, but they are data-intensive and most regions lack accurate distribution maps for the majority of species. We explored implications of basing conservation planning decisions on incomplete and biased data using occurrence records of the plant family Proteaceae in South Africa. Treating this high-quality database as 'complete', we introduced three realistic sampling biases characteristic of biodiversity databases: a detectability sampling bias and two forms of roads sampling bias. We then compared reserve networks constructed using complete, biased, and randomly sampled data. All forms of biased sampling performed worse than both the complete data set and equal-effort random sampling. Biased sampling failed to detect a median of 1-5% of species, and resulted in reserve networks that were 9-17% larger than those designed with complete data. Spatial congruence and the correlation of irreplaceability scores between reserve networks selected with biased and complete data were low. Thus, reserve networks based on biased data require more area to protect fewer species and identify different locations than those selected with randomly sampled or complete data.  相似文献   

2.
THOMAS, G. J., GLOVER, J. & MAKEPEACE, P., 1989. Management plan for the Royal Society for the Protection of Birds reserve at Dungeness, Kent . A synopsis of a new management plan for RSPB Dungeness reserve is presented.  相似文献   

3.
自然保护区设计的主要原理和方法   总被引:13,自引:0,他引:13  
本文回顾了自然保护区设计的主要原理和方法。建立自然保护区的目的是防止物种绝灭和生物多样性消失。岛屿生物地理学的“平衡理论”的设计原则未涉及到物种绝灭的中心问题———种群生存力,所以该理论对保护实践贡献较小。种群生存力分析和最小可存活种群的理论及模型用于物种绝灭问题的研究,同时关键种的生存力用于确定生态系统的生存力,因而该理论和模型成为自然保护区设计的理论基础。保护评估方法已应用于自然保护区的选择和检验中。走廊辩论取代了SLOSS辩论,成为自然保护区设计争论的热点  相似文献   

4.
Aim This study examines the effectiveness of the selected ‘network’ of Natura 2000 Special Areas of Conservation (SACs) at a regional scale in Greece, in terms of its representativeness of plant biodiversity. Location The island of Crete is used as a case study because it is considered to be one of the 10 hotspots for biodiversity in the Mediterranean Basin. Methods Hotspot analysis and complementarity algorithms are used to define priority areas for conservation and calculate their spatial overlap with the Natura 2000 SACs in Crete. Results The various categories of hotspots contain subsamples of plant categories, used for their definition. Spatial overlap among different categories of hotspots, areas of complementary diversity and Natura 2000 SCAs is low. Main conclusions The results show that the Natura 2000 SACs ‘network’ in Crete seems insufficient to ensure satisfactory representation of the regional plant biodiversity elements.  相似文献   

5.
Meta-analyses of published data for 19 marine reserves reveal that marine protected areas enhance species richness consistently, but their effect on fish abundance is more variable. Overall, there was a slight (11%) but significant increase in fish species number inside marine reserves, with all reserves sharing a common effect. There was a substantial but non-significant increase in overall fish abundance inside marine reserves compared to adjacent, non-reserve areas. When only species that are the target of fisheries were considered, fish abundance was significantly higher (by 28%) within reserve boundaries. Marine reserves vary significantly in the extent and direction of their response. This variability in relative abundance was not attributable to differences in survey methodology among studies, nor correlated with reserve characteristics such as reserve area, years since protection, latitude nor species diversity. The effectiveness of marine reserves in enhancing fish abundance may be largely related to the intensity of exploitation outside reserve boundaries and to the composition of the fish community within boundaries. It is recommended that studies of marine reserve effectiveness should routinely report fishing intensity, effectiveness of enforcement and habitat characteristics.  相似文献   

6.
我国国家级自然保护区数量特征研究   总被引:2,自引:0,他引:2  
研究我国国家级自然保护区数量特征对加强保护区建设和管理具有重要意义。本文通过资料收集,采用方差分析、多元比较、相关分析等数理统计方法,分析了我国国家级自然保护区数量和面积的分布格局、各类型保护区各功能区划面积比例及功能区面积与物种的关系等数量特征。结果表明,我国国家级自然保护区数量上以森林生态系统类型最多;面积上为荒漠生态系统类型最大;面积分布格局呈现从西向东及从北向南逐渐减少的趋势。方差分析表明不同类型国家级自然保护区3个功能区面积所占其总面积的比例之间差异不显著;相关分析表明在以物种为保护对象的保护区中,其总面积、各功能区面积与物种数量、动植物种类的相关性显著。该研究相关结果为我国自然保护区的建设与管理提供一定的参考依据。  相似文献   

7.
Iterative reserve selection algorithms were applied to two mammal databases, generalized to sixteenth degree grid squares, for the Transvaal region of South Africa. Based on primary point data, 24 grid squares are required to represent all species at least once, while only 13 grid squares are required when based on distribution map data; only two of these grid squares are common to both analyses. As the number of representations per species is increased from one to five, the number of selected grid squares increased to 86 and 71 or 72 respectively, with only 17 of these common to both analyses. These differences in the selection of sites are further reflected in the degree of congruence between selected grid squares and existing conservation areas which is on average 63.3% for grid squares selected from the primary database and only 42.5% for those selected from the distribution map database. These results emphasize the importance of quality data input when evaluating regional reserve networks. Highly generalized distribution map data sets, on the one hand, are extrapolations of limited data sets and contain non-quantifiable levels of false-positives which could have significant implications if used for establishing regional reserve networks. On the other hand, although there are problems associated with the establishment of primary diversity databases, namely data currency and uneven and non-random sampling (leading to false negatives), they remain our most reliable option for assigning conservation value.  相似文献   

8.
9.
自然保护区规划是保护生物多样性的有效方式.传统保护区规划方法只能识别物种保护的重点区域,无法科学确定保护区的适宜面积.地块选择方法基于数学模型,从规划区域中选择部分地块组成自然保护区,保护特定物种或生态系统,是缓解生态保护与开发利用矛盾的重要手段.现有地块选择法未考虑各单元生态差异,且最优化算法存在计算效率的瓶颈.本文首先构建适用于森林生态系统的生态值赋分评价体系,据此计算戴云山生态值并绘制其分布图;然后,结合生态值建立生态集合覆盖模型(ESCP),并基于ESCP嵌入空间紧凑性提出空间生态集合覆盖模型(SSCP);最后,利用寻优性能良好的自学习禁忌搜索算法(STS)搜索各保护目标下的近似最优选址方案,给出福建省戴云山现有建成区优化方案.结果表明: 戴云山生态值计算结果在空间分布上存在明显差异;ESCP比原集合覆盖模型(SCP)能产生生态值更高的选址方案;SSCP在ESCP基础上对生态值较高区域有聚集作用,且周长权重越大,聚集效果越明显;建议现保护区可向外拓展136 km2,并将西北向分布长苞铁杉的地块纳入保护区范围.研究结果为实现戴云山保护区可持续发展及土地资源优化配置提供了优化方案,也可为我国森林生态系统类型的自然保护区设计提供新思路.  相似文献   

10.
巢址选择作为鸟类繁殖的重要环节,是动物生态学关注的热点问题。为探究中等体型湿地鸟类普通鸬鹚的巢址选择偏好及主要影响因子,2019年4—10月运用秩和检验、主成分分析等方法对黑龙江龙凤保护区内普通鸬鹚巢特征、巢址特征、巢址选择进行了分析。结果表明:(1)普通鸬鹚偏好选择巢树乔木相对较矮(P<0.05)、周围灌木相对较矮(P<0.01)、植被盖度较低(P<0.01)、人为干扰距离较远(P<0.01)、距水面距离较远(P<0.05)的区域筑巢;(2)影响普通鸬鹚巢址选择的因子为隐蔽因子(20.634%)、巢稳定因子和干扰因子(27.614%)、植被因子(13.901%)、水因子(5.782%)和巢忠诚度(5.069%)。进一步分析表明:(1)普通鸬鹚倾向选择粗细适中的巢材,巢材来源于优势植被,巢深随纬度增高而增大;(2)巢区植被特征符合普通鸬鹚对能量支配的权衡,巢区粪便对该特征有强化作用。基于上述结果,建议龙凤保护区在巢区内加种高大乔木。  相似文献   

11.
后河自然保护区周边地区细痣疣螈资源及夏季生境选择   总被引:1,自引:0,他引:1  
2010年7-8月在后河国家级自然保护区及周边地区,运用样方法对细痣疣螈(Tylototriton asperrimus)的种群数量、分布及栖息生境进行了调查,并利用生境喜好系数和主成分分析法对细痣疣螈的夏季生境选择进行了分析.结果发现:细痣疣螈主要分布于与后河自然保护区毗邻的长乐坪镇及其附近区域,栖息地海拔450 ~ 1400 m,分布面积约550km2;在调查的103个样方中,有18个样方共发现细痣疣螈68条,种群数量较少;通过生境偏好系数分析发现,细痣疣螈偏好选择的微生境为:距小型静水塘(水体面积≤20 m2)51~100 m、距居民点101 ~500 m、距农田≤50 m、距道路≤100 m、草本盖度61% ~80%、草本高度21 ~40 cm、地表湿度61% ~80%、地表温度24℃~27℃的枯枝腐叶和草地生境;主成分分析表明,温度、植被、水体类型、人为干扰和食物是影响细痣疣螈夏季生境选择的主要因子.  相似文献   

12.
人类活动对中国国家级自然保护区生态系统的影响   总被引:4,自引:0,他引:4  
曹巍  黄麟  肖桐  吴丹 《生态学报》2019,39(4):1338-1350
我国已建立了超过2740个自然保护区,面积约占陆地国土面积的14.8%。以我国446个国家级自然保护区作为研究对象,基于遥感信息提取、模型与方程估算、时空趋势分析,揭示2000—2015年不同类型自然保护区、自然保护区不同区域生态系统质量和关键服务的时空变化特征,利用土地覆盖变化量化人类活动并进一步分析人类正面与负面活动对生态系统质量和关键服务的影响。结果表明:(1)国家级自然保护区内土地覆盖变化表明存在不同程度的人类活动,总体表现为保护区外较保护区内剧烈,说明保护区对生态系统具有明显保护作用。(2)农田开垦、居民点修建、工矿建设、能源资源开发等人类活动对保护区生态系统的负面影响表现为草地、湿地开垦导致耕地、水库坑塘面积增加,城镇居民点与工矿建设用地扩张侵占草地。(3)湿地面积净增加而林地、草地面积净减少,反映了湿地保护、退田还湖等措施的积极作用,然而退耕还林、退牧还草局限于部分保护区;(4)气候变化是自然保护区植被覆盖度微弱上升、净初级生产力下降、生态系统水源涵养量微弱增加、土壤保持量明显增加的主要原因,而人类活动仅在局部对生态系统产生影响。为了推动我国自然保护区体系的完善和保护作用的发挥,需要统一保护区建设标准及其规范,完善保护区法律制度,积极开展相关基础科学研究。  相似文献   

13.
冷仙  曾源  周键  杨飞龄  武瑞东 《生态学报》2023,43(3):1040-1053
定期开展保护成效评估,是制定保护决策与提升保护地管理效果的重要基础。景观动态能够直观地指示保护地成效,但针对区域尺度保护地网络,采用多指标评价体系的景观保护成效研究还相对缺乏。以我国西南地区102个国家级和省级自然保护区为研究对象,从景观生态状况、自然生境格局与连通性以及人类干扰4个方面构建评价指标体系,应用熵权TOPSIS模型的综合分析方法,评估自然保护区在1990—2015年间的景观保护成效,并探讨自然保护区属性与保护成效间的关系。研究发现:(1)从1990—2000年至2010—2015年评估时段,保护成效上升的自然保护区数量约占77.5%,但低于保护成效综合评价指数平均值的自然保护区数量持续增加,表明自然保护区的整体景观成效趋于两极化发展。(2)自然保护区景观保护成效表现出明显的空间差异性,保护成效明显提升的自然保护区主要分布在川藏滇桂四省区,成效下降的自然保护区主要分布在黔、桂及两者交界区域。(3)不同类型与等级的自然保护区之间保护成效存在差异。类型上,整体成效表现为森林生态类较好、内陆湿地类次之、野生动植物类较差,而保护成效改善程度为野生动物类>内陆湿地类>森林...  相似文献   

14.
白山原麝国家级自然保护区獐春夏生境选择   总被引:2,自引:2,他引:2  
生境与动物个体密切相关,生境中元素的不同影响着动物个体对不同生境的选择。2018年5-7月和2019年3-4月在吉林省白山原麝国家级自然保护区对獐(Hydropotes inermis)的春夏季生境选择进行了研究,共记录利用样方104个(春季53个,夏季51个),对照样方85个(春季46个,夏季39个)。利用卡方检验对植被类型、优势植物、坡位、坡向4种非数值型环境因子进行分析,结果表明春季和夏季獐对这4种环境因子的选择均具有显著性差异,偏好选择以青蒿(Artemisia carvifolia)为优势植物,位于中坡位,坡向为阳坡的草地生境活动。利用独立样本T检验和Mann-Whitney U检验对海拔、人为干扰距离、水源距离、草本覆盖度、优势草本高度、隐蔽级、坡度7种数值型环境因子进行分析,结果表明春季和夏季獐均偏好选择隐蔽级较高(春季30.189±14.609,夏季62.745±29.737)、优势草本高度较高(春季87.359±16.190,84.510±29.618)、坡度较缓的生境(春季14.245±3.721,13.333±5.260)活动。此外,资源选择函数模型对獐的春季和夏季的生境选择预测正确率均大于90%,表明该模型可以较好地预测獐的生境选择。白山原麝国家级自然保护区獐种群数量较小,适宜性栖息地面积较少,应加强对其种群及适宜性生境的保护。  相似文献   

15.
内蒙古达赉湖自然保护区狼的生境受到了自然环境变化压力和人为干扰的严重影响。为了解内蒙古达赉湖自然保护区狼的冬季生境特征,于2008年10-12月,在内蒙古达赉湖国家级自然保护区对狼的冬季生境选择进行了研究。野外共测量了59个20m×20m样方中的11个生态因子,运用聚类分析和主成分分析法,对狼的冬季生境选择因子进行了分析。结果表明,狼的生境主要特征为:隐蔽程度中等以上,水源距离100m,生境类型为高草阔地、干旱苇塘和河套,植被类型是以芦苇和柳灌丛为优势种的沼泽植被,植被高度1.0m,食物丰富度良好,居民点距离1000m,距草原道路距离1000m,牧场距离500m。影响狼冬季生境选择的主要因子为植被高度、植被类型和隐蔽级。次要因子为距围栏距离、雪深、距水源距离、生境类型、距牧场距离、食物丰富度和距居民点距离。  相似文献   

16.
Aims Climate change in the near future may become a major threat to high-altitude endemics by greatly altering their distribution. Our aims are to (i) assess the potential impacts of future climate change on the diversity and distribution of seed plants endemic to the Tibetan Plateau and (ii) evaluate the conservation effectiveness of the current National Nature Reserves (NNRs) in protecting the endemic plants in the face of climate change.  相似文献   

17.
Many animals rely on fat reserves, to keep them alive through extended periods of food shortage, such as the winter, and to provide additional energy for reproduction. Fat reserves, measured relative to an animal's size, are often referred to as the animal's body condition. The present study investigated how different levels of grazing by domestic stock in native grassland habitat affect the body condition of the pygmy bluetongue lizard (Tiliqua adelaidensis), and if these effects are related to changes in the abundance and size of grasshoppers which are the lizards primary source of food. The initial hypothesis was that lizards would have the highest body condition in moderately grazed paddocks, because those paddocks would have more grasshoppers than heavily grazed paddocks, and better visual conditions for lizards to catch those grasshoppers than in ungrazed paddocks. The results, however, showed that both lizard body condition and the abundance of grasshoppers increased with decreasing grazing intensity. The connection between lizard body condition and abundance of grasshoppers was complex. Within an activity season, lizard body condition generally declined from spring to summer, while the number of grasshoppers grew. The mean size of grasshoppers seemed to be more important, as lizard body condition was higher in spring, the time of year with the largest grasshoppers. These results show that the intensity of grazing by domestic stock influences the body condition of pygmy bluetongue lizards, but that this effect is not entirely due to the reduction in the number of grasshoppers resulting from grazing.  相似文献   

18.
Previous univariate studies of the yellow dung fly (Scathophaga stercoraria) have demonstrated strong sexual selection, in terms of mating success, on male size (estimated as hind tibia length). To identify specific target(s) of selection on body size and possible conflicting selection pressures on particular body parts, two multivariate field studies of sexual selection were conducted. In one study using point samples from three populations, we assessed several morphological traits, including genital traits and measures of fluctuating asymmetry (FA) of all paired traits. There was sexual selection for large male size in general, confirming previous, univariate studies. With the possible exception of thorax width, which was selected in the opposite direction, no main target of selection was identified, as most morphological traits were highly correlated. There was no detectable sexual selection on the male external genital structures assessed. In a second study using multiple samples from one population, we included physiological measures of energy reserves (lipids, glucose and glycogen) known to affect mating success, in addition to trait size and FA of wings and legs. Inclusion of physiological traits is rare in phenomenological studies of selection. This study again confirmed the mating advantage of large males, and additionally showed independent positive influences of lipid and glucose but not glycogen levels. FA in paired traits generally did not affect male mating success, but was negatively correlated with energy reserves. Our study suggests that inclusion of physiological measures and genital traits in phenomenological studies of selection would be fruitful in other species.  相似文献   

19.
旅游开发对东灵山亚高山草甸的影响   总被引:19,自引:0,他引:19  
旅游开发对东灵山亚高山草甸的影响刘鸿雁崔海亭张金海向国良(北京大学城市与环境学系,100871)EffectsofRecreationalDevelopmentontheSubalpineMeadowinDonglinMountain.LiuHong...  相似文献   

20.
The competitiveness of online algorithms is measured based on the correctness of the results produced and processing time efficiency. Traditionally evolutionary algorithms are not favored in online paradigms because of the large number of iterations involved in the algorithm which translates directly into processing time overhead. In this paper we describe MARS (Management Architecture for Resource Services) online scheduling algorithm which uses Simulated Annealing and concepts from Tabu Search to drastically decrease the processing time of the algorithm. The paper outlines the concepts behind MARS, the components involved and scheduling methodology used. In addition we also identify the time consuming bottlenecks in the performance of the system and how evolutionary algorithms help us soar past them.
Hesham El-RewiniEmail:
  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号