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91.
The process of habitat degradation varies in habitat type and driving force which shows certain spatial and temporal heterogeneity on regional scales. In the present study, a new diagnostic model for enclosed bay habitat degradation was established, with which the spatial and temporal variation patterns of habitat degradation during 1991–2012 in Sansha Bay, Fujian, China was investigated. The results show that anthropogenic disturbance is the major controlling factor for the habitat degradation in large temporal heterogeneity in the bay. On the other hand, the habitat degradation experienced signifi cant spatial variations among six sub-bays. Under the joint action of temporal and spatial heterogeneity, the degradation trend in growing scale shows a more signifi cant correlation with the distribution of local leading industries along shorelines. Therefore, we quantifi ed the main characters of habitat degradation in Sansha Bay, and have understood the relationship between the status of habitats spatio-temporal variation value and the main controlling factor leading to the changes. However, a defi ciency of this research is the lack of or inaccessible to the detailed data, which shall be better solved in the future study for accessing more data from more sources. 相似文献
92.
XU Weihua Andrés VIA QI Zengxiang OUYANG Zhiyun LIU Jianguo LIU Wei WAN Hui 《中国地理科学(英文版)》2014,24(1):60-70
Many nature reserves are established to protect the habitat needs of particular endangered species of interest but their effec-tiveness for protecting other species is questionable.In this study,this effectiveness was evaluated in a nature reserve network located in the Qinling Mountains,Shaanxi Province,China.The network of reserves was established mainly for the conservation of the giant panda,a species considered as a surrogate for the conservation of many other endangered species in the region.The habitat suitability of nine protected species,including the giant panda,was modeled by using Maximum Entropy（MAXENT） and their spatial congruence was analyzed.Habitat suitability of these species was also overlapped with nature reserve boundaries and their management zones（i.e.,core,buffer and experimental zones）.Results show that in general the habitat of the giant panda constitutes a reasonable surrogate of the habitat of other protected species,and giant panda reserves protect a relatively high proportion of the habitat of other protected species.Therefore,giant panda habitat conservation also allows the conservation of the habitat of other protected species in the region.However,a large area of suitable habitat was excluded from the nature reserve network.In addition,four species exhibited a low proportion of highly suitable habitat inside the core zones of nature reserves.It suggests that a high proportion of suitable habitat of protected species not targeted for conservation is located in the experimental and buffer zones,thus,is being affected by human activities.To increase their conservation effectiveness,nature reserves and their management zones need to be re-examined in order to include suitable habitat of more endangered species.The procedures described in this study can be easily implemented for the conservation of many endangered species not only in China but in many other parts of the world. 相似文献
93.
Road impacts on spatial patterns of land use and landscape fragmentation in three parallel rivers region, Yunnan Province, China 总被引：1，自引：0，他引：1
The structure and function of network is a central issue in landscape ecology.Road networks with hierarchical structure are crucial for understanding landscape dynamics.In this study,we compared the distribution of national road,provincial road,county road and rural road in the Three Parallel Rivers Region(TPRR)in Yunnan Province of China,and estimated the effect of roads(and other factors)on the spatial patterns of land use and land cover with logistic regression.In addition,we analyzed the land use and land cover change(LUCC)and landscape fragmentation in 1989–2005 along a buffer zone of the primary traffic corridor,national road G214.The results showed that,county and rural roads had much higher percentage of length extending into more natural habitats at higher elevation and steeper slope,compared with the higher level roads in this region.While the distributions of natural land cover types were dominated by environmental factors,human land use types i.e.,building land and farmland types were significantly related with roads,linking more closely with lower level roads.The LUCC dynamics(1989–2005)of the G214 buffer zone showed a general trend of land transformation from conifer forests and valley arid shrubs to building land and farmland,and from ice and snow to alpine shrubs and forests.With the length of G214 unchanged during the time,the overall landscape pattern changed little in the buffer zone,but habitat fragmentation and area decrease had occurred for the natural vegetation types,in contrast to patch mergence and expansion of human land use types,and landscape fragmentation was intensified above 2500 m a.s.l.but declined below the elevation.The results indicated the dynamics of landscape composition and patch type level distribution in spite of the stability of the overall landscape pattern,and implied the potential role of roads,especially the low level roads on landscape changes. 相似文献
94.
Specimens of a new species of Cerithiidae, Cerithium mangrovum n. sp., were collected during two surveys along the coasts of Hainan and Guangdong Province, China. Usually associated with potamidid snails, this species often occurs in large populations between the mid-high tidal zones in a range of habitats, including mangroves, grass beds, silt, mud, and coral reefs. C. mangrovum n. sp. has a slender and tapering shell and the straight-sided whorl bears three aligned beaded spiral cords. The thick outer lip has a wide posterior sinus. It morphologically resembles C. coralium Kiener, 1841. The shell of C. coralium is usually larger and wider and the spiral cords are not as beaded as in C, mangrovum n. sp. Its radula has a rachidian tooth with a shallow, wide, median basal projection while the rachidian tooth of C. mangrovum n. sp. has a moderately long, median basal projection. 相似文献
95.
96.
两类强度厄尔尼诺和拉尼娜事件对中国近海鲐鱼栖息地的影响 总被引：5，自引：1，他引：4
鲐鱼是中上层鱼类，具有较高经济价值，其种群受到气候和海洋环境的显著影响。本文根据2006-2015年7-9月中国远洋渔业数据中心提供的中国近海鲐鱼捕捞和海表温度以及海面高度两个关键环境因子的数据，构建了基于捕捞努力量的鲐鱼综合栖息地指数模型，分析研究了在不同强度厄尔尼诺和拉尼娜条件下鲐鱼栖息地适宜性的变动规律。通过计算和交叉验证，结果发现，基于算术平均法的栖息地模型能够较好地预测鲐鱼渔场栖息地适宜性指数。空间相关性结果表明，鲐鱼渔场主要作业海域范围内海表温度异常与栖息地指数值呈显著正相关关系，而海表面高度异常与栖息地指数值呈显著负相关关系。不同强度厄尔尼诺和拉尼娜事件对鲐鱼种群影响不同，具体表现为:相对于中强度厄尔尼诺事件（或中强度拉尼娜事件），超强厄尔尼诺事件（或强拉尼娜事件）驱动鲐鱼主要作业海域内温度下降（或上升），海面高度上升（或降低），鲐鱼渔场适宜栖息地面积显著减小（或增大），导致鲐鱼单位捕捞努力量渔获量骤减（或显著增加）。研究表明，中国近海鲐鱼栖息地适宜性与厄尔尼诺和拉尼娜事件显著相关，且随着异常气候事件强度的不同而发生变化。 相似文献
97.
98.
海州湾春季皮氏叫姑鱼栖息地适宜性研究 总被引：4，自引：0，他引：4
根据2011年及2013-2015年春季在海州湾及其邻近海域进行的底拖网调查数据，结合同步采集的底层水温、底层盐度、水深以及资源密度等数据，开展皮氏叫姑鱼（Johnius belangerii）栖息地适宜性的相关研究。利用提升回归树（boosted regression tree，BRT）模型确定各环境因子的权重，分别采用算术平均法（AMM）和几何平均法（GMM）建立栖息地适宜性指数（habitat suitability index，HSI）模型，并通过交叉验证确定最优模型。结果表明，皮氏叫姑鱼幼体最适栖息的底层水温为17.4~18.0℃，底层盐度为29.2~30.8，水深为7 m以浅；成体最适栖息的底层水温为17.3~18.0℃，底层盐度为28.8~30.8，水深为12 m以浅。根据BRT模型的输出结果显示，对皮氏叫姑鱼幼体总偏差贡献率最大的是水深，其次是底层盐度和底层水温；对成体总偏差贡献率最大的是底层水温，其次是水深和底层盐度。通过交叉验证发现，无论幼体还是成体，运用GMM算法，且赋予权重的HSI模型具有较低的赤池信息准则值（akaike information criterion，AIC）。海州湾春季皮氏叫姑鱼的最适栖息地随生长阶段而变化，幼体的最适栖息地（HSI ≥ 0.7）主要分布在7 m等深线以浅的山东、江苏沿岸海域；成体的最适栖息主要分布于12 m等深线以浅的海域。海州湾春季皮氏叫姑鱼幼体和成体最适栖息地的空间分布与其自身的生态习性、外界环境因子以及黄海冷水团、近岸沿岸流等因素密切相关。 相似文献
99.