Characteristics Of Reproduction And Spread For Aconitum Leucostomum Worosch Population In Nalati Mountain Meadow

At this stage, Nalati mountain meadow is covered with poisonous plants including Aconitum leucostomum Worosch. In order to better provide an ecological restoration theoretical for the Nalati mountain meadow. First, we should grasp the Nalati mountain meadow grassland degradation mechanism.Then to master the major poisonous weeds A. leucostomum Worosch population endangering mechanism. The core test area was set at Nalati steppe typical location in2006, which included500acres fence and outside the fence areas. Two plots were set which have completely different uses types as our object of study.(Plot1, fencing then mowing at the end of August. Plot2, for free grazing). Also A. leucostomum Worosch’individuality was basic research unit:(1) Methods of a species diversity, Sorensen community similarity index, the overall relevance and significance test,2×2contingency table of Fisher exact test, Pearson correlation analysis and Spearman rank correlation analysis are adopted to analyze the degraded grassland community and interspecific association changing after transform the using patterns.(2) Using Mean crowding m*, the index I, m*/m, CA, the diffusion coefficient C, negative two parameters K, and Moristia index Iδ to analyze the A. leucostomum Worosch population distribution characteristics and internal correlation.(3) The proportion of sexual reproduction inputs and record seeds landing were surveyed. The law of reproductive allocation, sexual reproduction and asexual reproduction, spread were analyzed. The ability of regeneration after the different disturbances was studied.The main results were as follows:1. A. leucostomum Worosch was harmful in test area. Even for four consecutive years of fencing and mowing utilization was still not fundamentally changed the grassland degradation state. However, fencing able to control the clonal spread of A. leucostomum Worosch to a certain extent, inhibit its strains Cong growth. 2. In the two plots, A. leucostomum Worosch populations are showed from aggregated distribution changing to the random then even the uniform distribution with the strains cong growing. And between different strains of cong has no significant exclusion. Therefore, relying solely on the mild manner of the demise of populations within and reducing stocking rates can not suppress the further expansion of its population.3. A. leucostomum Worosch populations have two kinds of reproduction for sexual reproduction and asexual reproduction. Asexual reproduction of the early spring for its green and growth process space competition to provide support. The law of sexual reproduction is also adapted to local environmental features, overgrazing could promote the seed output, then exacerbate its spread. And sexual reproduction of the low-altitude input distribution was significantly greater than the high altitude, showed that A. leucostomum Worosch population tends to spread to the lower elevations.4. The best period to prevent A. leucostomum Worosch harms is in reviving stage to flowering that can inhibit of sexual reproduction at the same time and weaken the asexual reproduction at the greatest degree. For example, we from reviving stage to start an interval of30days twice mowing could control basically the A. leucostomum Worosch populations of sexual reproduction, to control the sexual spread and ultimately prevention.