The Research Of Spatial Distribution Patterns In Stipa Breviflora Desert Steppe

With the fifteen plant populations in Stipa breviflora desert steppe in Siziwang Banner of Inner Mongolia as research object, with the eighteen percents and eight percents covering as contrast, the following four problems were researched and discussed:the plant populations of space distribution style,aggregation intensity, pattern scale and reasons for aggregation. The result showed:1. The fifteen plant populations in Stipa breviflora desert steppe, Allium mogolicum, Kochia prostrata and Neopallosia pectinata were aggregated distribution, Caragana microphylla was equally distribut under eighteen percents covering; Stipa breviflora, Cleistogenes songorica and Neopallosia pectinata were aggregated distribut under eight percents covering. From different direction, the research showed the distribution style of big clump was different, but the middle and small clump were consistent.2. From the research of five predominance plant populations, under eighteen percents covering, there was a scale exist on five plants populations in the south and north, east and west, southeast three different direction, but in the northeast, only the Stipa breviflora and Cleistogenes songorica had a scale, and the rest did not exist any scale. Under eight percents covering, Stipa breviflora had a scale in the southeast and southwest, Cleistogenes songorica had a scale in the south and north, east and west, southeast, and in the northeast, Cleistogenes songorica had two scales. In the four directions, Artemisia frigida didn't have any scale.3. There was evidence difference on the aggregation of plant population under different covering and different clump. such as the aggregation of Allium mogolicum and Kochia prostrata in big clump were highest under eighteen percents covering, the aggregation of Stipa breviflora and Cleistogenes songorica were highest in the eight percents.4. Under eighteen percents covering, the six plant populations with aggregated distribution, such as Stipa breviflora, Cleistogenes songorica, Convolvulus ammannii, Kochia prostrata, Neopallosia pectinata and Artemisia frigida, when the population density was below 4.7plants/m~2,4.2plants/m~2,0.5plants/m~2,3.9plants/m~2,2.8plants/m~2 and 3.5plants/m~2, the population aggregation was caused by the explicit environment genes, contrarily, the population aggregation was caused by aggregation action and colligation environment genes.under eight percentscovering, when the population density was below 3.3plants/m~2,3.8plants/m~2,2.2plants/m~2,2.2plants/m~2,2.7plants/m~2 and 0.9plants/m~2, the population aggregation was was caused by some explicit environment genes, contrarily, the population aggregation was was caused by aggregation action and colligation environment genes.