Spatial Pattern In The Structure And Diversity Of The Taxonomic And Functional Organizations Of Stream Fish In The Mountains Of Southern Anhui

Stream fish assemblages is the combined production of current andhistorical factors, the relative importance of various environmental factorsaffect fish community depends on the choice of space scale and the selectionof assemblages characteristic variables. Identifying the spatial pattern of thefish assembls structure and diversity and analyzing all kinds of environmentfactors on the fish assemblages, conservation and management of fish speciesand rational utilization of resources are very important. The research area wasthe headwater streams of Qingyi River，Qiupu River, Chang River andXin’an River in in the mountains of southern Anhui. Based on the analysis offish species composition, the research of fish morphological and trophiccharacters and careful sample setting with a large number of field sampling.Systematically studied the spatial distribution pattern of the structure anddiversity of the fish taxonomic and functional organizations in the mountainsof southern Anhui, analyzed the local habitat, tributary space and regionallandscape factors affect fish assemblages. The main research results are asfollows:1. Fish taxonomic diversity and spatial distribution pattern.Two-way ANOVA test the impect of streams and stream order on fishassemblages, The results showed that specie richness, abundance andH-index varied significantly across stream order (P＜0.01),while speciesrichness, abundance and H-index didn’t vary significantly across streams (P＞0.05) and streams crossed stream order (P＞0.05). Stepwise linearregression analysis showed as follows: Specie richness varied significantlyacross link, water temperature, distance from the estuary, construction landarea, slope and distance from the headwater (P＜0.05). Abundance varied significantly across link, water depth, slope and distance from the estuary (P＜0.05). H-index varied significantly across stream order, water temperature,construction land area, distance from the estuary and grassland area (P＜0.05). Two-way ANOSIM test the impect of streams and stream order on fishassemblages, the results showed that fish assemblages overlapped and variedsignificantly across streams (P＜0.05),while they didn’t overlap and varysignificantly across stream order (P＞0.05). The results of redundancyanalysis showed that elevation, water temperature, conduction, water width,current velocity, substrate heterogeneity, stream order, slope, distance fromthe estuary, forest area and grassland area had important impact onassemblages structure (P＜0.05).2. Fish functional diversity and spatial distribution pattern.The results of two-way ANOVA test showed that morphological guilds,trophic guilds and combined guilds varied significantly across stream order(P＜0.01),while they didn’t vary significantly across streams (P＞0.05) andstreams crossed stream order (P＞0.05). Stepwise linear regression analysisshowed as follows: Morphological guilds varied significantly across streamorder, water temperature, distance from the estuary, construction land areaand distance from the headwater (P＜0.05). Trophic guilds variedsignificantly across link, water depth, D-link, distance from the estuary andwater area (P＜0.05). Combined guilds varied significantly across link, watertemperature, distance from the estuary, slope and construction land area (P＜0.05). Two-way ANOSIM test the impect of streams and stream order onfish guilds, the results showed that morphological guilds, trophic guilds andcombined guilds overlapped and varied significantly across streams (P＜0.05),while they didn’t overlap and vary significantly across stream order (P＞0.05). The results of redundancy analysis showed as follows: Elevation,water temperature, water width, stream order, slope, distance from the estuary,distance from the headwater and grassland area had important impact onmorphological guilds (P＜0.05). The results of redundancy analysis showedthat elevation, water temperature, conduction, water width, current velocity, substrate heterogeneity, stream order, slope, distance from the estuary, forestarea and grassland area had important impact on morphological guilds (P＜0.05). Trophic guilds were impacted by elevation, dissolved oxygen，watertemperature, substrate heterogeneity, stream order, slope and distance fromthe estuary (P＜0.05). Elevation, dissolved oxygen，water temperature,conduction, water width, substrate heterogeneity, stream order, slope,distance from the estuary, forest area and grassland area also had importantimpact on combined guilds (P＜0.05).As a whole, fish taxonomic and functional organizations of theheawaters in the mountains of southern Anhui showed a similar spatialpattern: the fish diversity change with stream order significantly, but heassemblages structure only had significant differences between rivers, andthedifferences are mainly caused by changes in the relative abundance ofcommon kinds. Local habitat, tributary space and regional landscape factorsimpact on the assemblages diversity and structure, its specific modelsdepending on the selected community characteristic variables are different.Local process on the influence of the spatial distribution of the headwaterstream fish assemblages in the mountains of southern Anhui was moreimportant than landscape processes between rivers, and local process closercontact the taxonomic organizations.