Species Diversity And Doninant Poulation Niche Of Different Communities In Qitai Desert Grassland Nature Reserve

The Qitai Desert Grassland Nature Reserve is the most representative of thetemperate semi-shrubs. It was of great value to typical and high conservation in China’sinland desert natural ecosystem, which played an important role in climate regulation andmaintenance of the regional ecological balance. Aimed at providing a theoretical basis forprotecting and restoring the desert vegetation in this area, through field investigation andstatistical analysis method, we made a research on Qitai Desert Grassland Nature Reserveto make deep investigation on species diversity and dominant populations niche.The results showed the communities of species in Qitai Desert Grassland NatureReserve belonged to Central Asia and West Asia ingredients, and the Shannon-Wienerdiversity index was between1.336to2.074, which was generally low. It was mainlybecause the local ecosystem was poor in habitat conditions, resulting in few communitycomposition, simple structure and low organization level. Typical species diversity indexorder was: Haloxylon ammodendron+Ceratocarpus arenarius>Haloxylonpersicum+Ceratoides latens> Haloxylon persicum+Aristideae pennata>Haloxylonammodendron+Phragmites australis>Haloxylon ammodendron+Bassia dasyphylla>Phragmites australis+Salsola collina Pall> Haloxylon ammodendron+Seriphidium terrae-albae>Haloxylon persicum+Reaumuria soongorica> Haloxylon persicum+Agriophyllumsquarrosum> Haloxylon persicum+Anabasis elatior>Haloxylon ammodendron+Suaedaglauca> Haloxylon persicum+Atraphaxis spinosa> Haloxylon persicum+Ceratocarpusarenarius> Haloxylon persicum+Seriphidium santolinum.Through the analysis of the relationship between the typical community speciesdiversity and soil factors, it showed a significant positive correlation (R=0.791，P＝0.023)in soil pH and Pielou evenness index (Jsw). The soil salinity showed a significant positivecorrelation both in Pielou evenness Index Jsw (R=0.823，P＝0.025) and Pielou evennessindex Jsi (R=0.6417，P＝0.035). Soil organic matter and Pielou evenness index Jswpresented a significant positive correlation (R=0.363, P=0.047), and it did not achievesignificant correlation with other diversity index (P>0.05).Through the plant species niche breadth and niche overlap in14main typicalcommunity, the results showed that the plant population niche breadth values range isbetween0.167and0.640. The overlap in the pH-dimensional had larger value, includingReaumuria soongorica and Salsola ruthenica(0.885), Reaumuria soongorica and Artemisiafrigida(0.788), Artemisia frigida and Salsola ruthenica(0.767). Overlap in the Soil totalsalt-dimensional had larger value, including: Artemisia frigida and Reaumuria soongorica (0.715), Agriophyllum squarrosum and Seriphidium santolinum(0.697), Artemisiafrigida and Ceratocarpus arenarius(0.684). It had high Overlap in soil organicmatter-dimensional, the species including Salsola ruthenica and Ceratocarpus arenarius(0.974), Salsola ruthenica and Reaumuria soongorica(0.988), Agriophyllumsquarrosum and Phragmites australis(0.706). The width of the niche was lower than thewoodland and shrubs grass, but it was higher than the desert ecotone. The overlap ofdominant species in protected areas was high in soil salinity and soil organic matter, whichcould indicate soil salinity and soil organic matter were two important limiting factors forspecies growth in protected areas.