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A Research on the Elevation Patterns of Species Diversity and Bio-productivity for the Shrub Communities in Arid Valley in the Upper Reach of Minjiang River

Author: ChenZuo
Tutor: MuChangLong；LiuJun
School: Sichuan Agricultural University
Course: Silviculture
Keywords: Minjiang River dry valley Shrub communities Diversity Productive forces Altitudinal patterns Environmental factors
CLC: Q948
Type: Master's thesis
Year: 2007
Downloads: 228
Quote: 3
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Abstract

Minjiang River dry valley - Zagunao River natural shrub vegetation of the arid valley area as the research object, altitudinal sampling survey by coastal shrubland vegetation characteristics of the area, the minimum area of ??community, species diversity Altitudinal patterns Altitudinal patterns of productivity, diversity and productivity as well as their relevance and environmental factors analysis, to find a leading environmental factors affect the diversity and productivity, which Minjiang River dry valley vegetation recovery more detailed basic information and theoretical basis. The main findings are as follows: 1. In the survey area, 107 kinds of vascular plants were collected, belonging to 41 families and 88 genera, including shrubs, 20 families, 34 genera and 45 species herbaceous 29 families, 56 genera, 62 species. Poor focus Branch plant species were Leguminosae Leguminosae, Asteraceae, Compositae, Rosaceae Rosaceae and Gramineae Graminea. Community structure characteristics with elevation changes with altitude gradually increased shrub community in performance by the arid shrub to semi-moist thickets excessive, its dominant species of principal components, the life form spectrum, frequency distribution many other aspects of shrub communities from simple single to complex over trend showed that more obvious species along the altitudinal gradient REPLACEMENT. 2. By species - area curve fitting each altitude shrub communities in the smallest area of ??research, presented for the first time the different altitude communities in the area including a minimum of 60 to 90% of the species area. The minimum area of ??shrub communities in four altitudinal gradient in descending order, shady slope order: 2165m> 1957m> 1558m> 1750m, the sunny order 2200m> 1985m> 1578m> 1781m along an altitudinal gradient increases at first less Altitudinal patterns; small and then increases the corresponding altitude, the altitude of 2000m minimum sampling area and number of species contained in shady slope was significantly greater than the sunny and shady slope and sunny slope in the high altitude of about 2200m close to. Quadrat area of ??100m 2 (10m x 10m), 200m (10m x 20m) minimum area of ??the Minjiang River dry valley shrub community to meet the requirements of the accuracy of different studies to reduce the number of investigations and the workload of the field plots. 3.4 altitudinal gradient shrub community in α diversity in descending order, shady slopes order: 2165m> 1957m> 1558m> 1750m, the sunny order 2200m> 1985m> 1578m> 1781m increasing altitude showed first Altitudinal patterns; reduced increase alpha diversity increase or decrease performance among altitudinal gradient: the sunny slope, herbs> shrubs; uphill in addition to an altitude of 2200m around the sunny herbaceous the α diversity than shady slope shady slope altitude lot of shrubs and herbaceous species-α diversity are greater than the corresponding section of the sunny slopes. 4. Overcast, sunny slope with increasing elevation, elevation about 1550m kind to other elevation gradient between the plots shrub communities shrubs and herbaceous β diversity index showed an increasing trend. The low altitude gradient gradients and high altitude shrub plant species and biotopes large differences, species similarity decreases with increasing altitude interval, species turnover rate increases. With increasing altitude interval, the north-facing slope of the adjacent plots between shrubs β diversity index showed a decreasing trend after the first increase, herbal β diversity index showed a decreasing trend; diverse β shrubs between the sunny slopes of the adjacent plots resistance index showed an increasing trend, herbal β diversity index showed an increasing trend in the first reduction. Shrubs in shady slope altitude of 1750m to 1957m between the difference in the most significant turnover rate of the fastest, the sunny slope altitude 1985m to 2200m between the difference in the most significant, the fastest turnover rate; herb in shady slope altitude of 1578m ~ 1750m difference between most significantly, the fastest turnover rate the sunny slope altitude 1985m to 2200m between the difference in the most significant turnover rate is the fastest. 5. Overcast, the sunny shrub shrub layer biomass accounted for an absolute advantage shady slope the shrub layers biomass size: shrub layer> herb layer> layer> litter layer; the sunny slopes shrub layers biomass Size: shrub layer> herb layer> litter layer> layer. Overcast, sunny shrub biomass of various organs: roots> stems> leaves> flowers and fruits. Rich shrub underground portion of biomass accumulation. The four altitudinal gradient shrub layers biomass and organ biomass Sorted shady slope order: 2165m> 1957m> 1558m> 1750m, the sunny slope followed 2200m> 1985m> 1578m> 178lm with elevation Altitudinal patterns; showed decreased and then increased shrub biomass in the shady slope altitude between 1750m ~ 1957m obvious differences, at the the sunny slope altitude of 1985m ~ 2200m obvious differences between. Overcast, shady slope the shrub layers biomass and the organ biomass than the sunny the sunny slope corresponding elevation gradient. Shrub layer, the ratio of the underground part of the aerial parts of the herb layer showed a decreasing trend after the first increase with elevation. 6. Shrub communities in shrubs and herbaceous diversity and biomass of a positive correlation between ecosystem productivity increases with the increase in species diversity. Species diversity, species composition, and biological characteristics of the species, climate and disturbance on a variety of factors have an impact on the relationship between species diversity and ecosystem function. 7. The lack of water, high alkaline, calcification and effective fertility level is low, the main characteristics of the soil in the area, and soil moisture conditions affect other characteristics of soil nutrient. 4 elevation gradient in soil chemical fertility level arrangement, shady slope order: 2165m> 1957m> 1558m> 1750m, the sunny slopes order 2200m> 1985m> 1578m> 1781m, and a different aspect: the shady slope> sunny. 8. Shrub species diversity and productivity and environmental factors correlation analysis showed that, altitude, aspect, slope, soil water content, available N, available K, organic matter, total N, K and shrub community diversity and productivity were positively correlation, a negative correlation between pH, available P, total P, total Ca diversity and productivity. By stepwise regression analysis and principal component analysis results show that the distribution of the vegetation of the area is soil moisture, soil nutrients and the result of the combined effects of micro-terrain three.

A Research on the Elevation Patterns of Species Diversity and Bio-productivity for the Shrub Communities in Arid Valley in the Upper Reach of Minjiang River

Abstract

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