Species Abundance Distribution Of Zokor Mound Plant Community Along Restoration Progress And Its Relationship With Mound Area

The plant community total abundance, richness and diversity index change along restoration succession. Island biogeography theory indicates that the larger island the more species and individuals. Zokoer mound can be seen as miniature island on the meadow. How do age and area of zokor mound effect the mound plant community? We investigated species abundance and richness of zokor mounds plant communities and researched the changes that species diversity and species abundance distribution (SAD) of zokor mound vegetation varied along succession. We also studied the relationship between species diversity, SADs of the plant communities and the island area. In addition, we tested whether the SAD fitted the geometric series, log-series, Hubbell model, broken sticks, normal distribution, power fraction and random assortment models. We found that:1) The species richness and total abundance significantly increased during the succession process. Shannon-Weiner index gradually became larger and tended to flatten from stage4and a slight decrease in stage7. The slope of SAD curves along with the succession turned out the same trends as Shannon-Weiner index. Moderate disturbance increased the species diversity. The SAD curve slope and evenness index showed different evenness changes of mound plant community. So using evenness index to characterize the community uniformity might be not reasonable. This result was consistent with the effect of mound size on the community evenness.2) Mound size did not significantly influence species diversity and SAD of mound plant community. While SAD curves of the four years old mound plant community between S2and S3were more different than the curves between S1and S2. There was no such trends among SAD curves of one year old mound plant communities with different areas. And species diversity of one-age mound community performed greater volatility than that of four ages mound community.3) Within the succession stages we studied, only geometric series could fit the communities in most restoration stages. Hubbell model, power fraction, log-series could not fit any community in any stage. Random assortment, broken sticks, normal distrubution could fit the communities in early stages. This result indicated a niche based community assembly in this plant community. And the allocation of resourses was not random. The result did not reflect a neutral progress.4)We used different models to fit SAD of zokor mound plant communities in different size. The models that could fit the SADs were all niche models. Statistical models and Hubbell model could not fit any mound plant community with different areas. Among one-age(stage3) mounds, there were more models can fit SAD of smaller mound plant communities. The models which could fit one-age mound plant community with different areas were different. We could see the same consequent among4-ages (stage6) mounds.