Dissertation > Excellent graduate degree dissertation topics show

The Research of Spatial and Temporal Patterns in Fish Assemblages During the Qingyi Watershed

Author: XiangXiuYing
Tutor: YanYunZhi
School: Anhui Normal University
Course: Hydrobiology
Keywords: Stream fish communities Dam Temporal pattern Local habitat Tributary spatial position Qingyi
CLC: S931.1
Type: Master's thesis
Year: 2011
Downloads: 96
Quote: 0
Read: Download Dissertation

Abstract

Identify and explain the distribution and abundance of fish in the river of spatial heterogeneity and temporal dynamics of river fish community ecology of one of the core issues. River fish community revealed multiple spatial and temporal scales in the distribution pattern of river fish survival and reproduction of essential habitat, resolve various environmental factors affect the mechanism of fish communities and their relative importance, not only to protect species of river fish and the rational use of fishery resources scientific basis for the river ecosystem conservation, restoration and management also has important scientific significance. This thesis is selected for the study of the Qingyi River Basin in Anhui Province to fish species composition, number of species and individuals as a community structure characteristic variables, focusing on the longitudinal gradient from the river and river network systems which two spatial scales reveals systematic Qingyi River fish community spatial distribution pattern and its seasonal dynamics, combined with the ecological environment factor analysis to resolve the fish community formation mechanism of temporal and spatial heterogeneity. The main results are as follows: 1. Fish communities in streams longitudinal gradient of spatial and temporal patterns: 2009 4,7,10 month, and in January 2010, on a quarterly basis Qingyi River watershed two longitudinal gradient of 1-5 reach a total of 15 study samples of fish communities were studied. Catches were collected 13,647 tails, total 57 kinds (including kiss goby genus of fish), belonging to 15 families and 5 orders, of which the largest number of cyprinid species, accounting for 59.6% of total catch; each sample collection number of species was 11.9 ± 6.6 species, the number of individuals of 227.6 ± 205.5 tail. According to three factor analysis of variance (Three-way ANOVA), the number of species of fish in streams and vertical gradient between level there was a significant difference between (P lt; 0.05), ie, the number of species increased with rising levels of streams by dams blocking gradient, the number of species is low; and different seasons of the number of fish species was no significant difference (P gt; 0.05). According similarity analysis (ANOSIM) and non-metric multidimensional variable ordering (NMS), fish community structure at different stream levels between the longitudinal gradient between both showed significant spatial variation (P lt; 0.05), but its seasonal dynamics was not significant (P gt; 0.05); according to the percentage of similarity (SIMPER) analysis, rare flowers mahi mahi piebald Vice sand, and Rhodeus OCELLATUS blacktip Quan and other changes in the number of species for the spatial variation of fish communities have higher contributions. Number of dams on fish species and community structure has obvious characteristics of locality, that is, only four river fish species number and community structure between the two longitudinal gradients significant difference. According to canonical correlation analysis (CCA), altitude, underwater substrate, flow, water depth, water and other environmental factors on wide fish community has an important impact on the spatial distribution. 2 fish communities in streams in the network system spatial pattern: in October 2009, on the Qingyi River basin of grade 1-3 89 samples of fish communities were studied, focused on the local habitat and tributary spatial position relative impact on the fish community. 9,875 were collected catches tail, total 36 kinds (including kiss goby genus of fish), belonging to 11 families and 4 orders. According to stepwise linear regression analysis, the number of major fish species and local habitat (water width and water temperature) was significantly correlated (P lt; 0.05), but the impact of tributary spatial position of lesser importance. According to canonical correlation analysis, the species composition of fish habitat by local (altitude, underwater matrix and depth) and tributary spatial position (C-link and Link) The combined effect was significant (P lt; 0.05). These results illustrate the effects of dams on fish migration route of the barrier effect, Qingyi River Basin fish species depends only on the number of local habitat characteristics and their spatial autocorrelation is very low; However, due to habitat for fish species choice may depend ecological characteristics of the species rather than the space of ecological processes, species composition and therefore subject to local habitat and tributaries combined effect of spatial location.

Related Dissertations

CLC: > Agricultural Sciences > Aquaculture, fisheries > Aquatic Resources > Aquatic Resource Science > Fisheries resources in ecology
© 2012 www.DissertationTopic.Net Mobile