黑河上游天然草地蝗虫空间异质性与分布格局

蝗虫空间分布格局是物种长期适应自然的结果,是蝗虫与环境、蝗虫之间关系的反映,有助于理解蝗虫发生学的环境背景。采用地统计学方法,在黑河上游山区天然草地研究了微生境影响下的蝗虫空间格局与异质性。结果表明:该区域5种优势种蝗虫的半变异函数模型均为非线性模型,表现为聚集分布;不同种类蝗虫样点之间空间依赖的范围为2.29—24.59 m;在蝗虫种群总异质性中随机部分引起的空间异质性占15.77%—88.64%。受食性和栖息地选择的影响,蝗虫种群形成了片状和斑块状的分布格局;尺度依赖性使蝗虫分布格局趋于多元化和繁杂化的特点,不同蝗虫种群之间相互交错嵌插,同种蝗虫高低值呈非均匀扩散,整体上形成了均衡性与互补性的斑块镶嵌结构,这种分布格局反映了蝗虫对生境和气候变化的多元适应性结构。

Analysis on grasshopper spatial heterogeneity and pattern of natural grass in upper reaches of Heihe

Grasshopper species spatial distribution pattern is the result of natural long-term adaptation, and a reflection of the relationship between grasshoppers and the environment. The spatial heterogeneity is an important theory basis to recognize the dynamic characteristics of the population development. To study the spatial distribution pattern of grasshoppers in natural grassland of heihe upstream in a quantitative research method, to analyze the spatial distribution characteristics of dominant species, then to determine the spatial structure features of grasshopper population and the spatial autocorrelation, all of what provided the theory basis to understand the ecological explanation of grasshoppers occurrence and distribution. On July 25, August 5, August 15, 2009, in the Baidaban, which locates at the south side of theater circles river- Heihe branch of north Qilian Mountain, a north-south investigation area with length of 3500m, width of 900m was set up along altitudinal gradients, combined with the survey data of wild vegetation communities, then 3-8 investigation plots were set in each type of grassland, and finally 36 representative kinds were chose out with each kind of 100 × 100 m², extracting three 50 m × 50 m rectangle sample point in double diagonal method from each standard plots, a total of 108 sample points. To take samples 3 times with no returns, each time with the insect net (net diameter 30cm) which were used to sweep 200 nets like parallel lines, each net with radian 180°, then collected grasshopper's abundance, density, many degrees in each type place according to each sample point's three statistical average. We tested the data using the statistical software SPSS (16.0) of the P-P normal probability graph method, and analyzed the grasshoppers regionalized variables space structure, simulation and spatial interpolation with statistic method in ArcGIS for the analysis of the grasshopper spatial distribution pattern, then calculated the space heterogeneity using a half variation function method. The results showed that: the dominant five kinds of grasshoppers in this region's semivariogram models are nonlinear models, showing aggregated distribution; different types of spatial dependence between samples of grasshoppers in the range of 2.29-24.59m; in the grasshopper population heterogeneity in the random part of the total due to spatial heterogeneity accounted for 15.77%-88.64%.Influenced by diet and habitat selectivity, the distribution pattern of grasshopper populations are flaky and patchy pattern of horizontal distribution in their formation process. Scale dependence of the grasshoppers become diversified and complex distribution pattern of the characteristics of cross between different species of grasshoppers intercalation, the same kinds of grasshoppers was non-uniform spread of high and low values the overall balance of the formation of a plaque inlaid with complementary structure, this distribution pattern reflects the grasshopper habitats and climate change on the diversity of adaptive structures. Grasshopper species spatial distribution pattern is the result of natural long-term adaptation, grasshoppers and the environment, a reflection of the relationship between grasshoppers, grasshoppers is to recognize the spatial heterogeneity of grasshopper population dynamics of the occurrence and development an important theoretical basis, taking quantitative research of Heihe River upstream of the natural populations of grasshoppers spatial distribution pattern, analysis of spatial distribution of dominant species of grasshoppers, grasshopper populations to determine the spatial structure and spatial autocorrelation, for understanding the occurrence and distribution of grasshopper environmental studies provide a theoretical basis to explain.