摘要：Biocomplexity theory is becoming increasingly important in understanding natural vegetation dynamics andinterrelation among all components of ecosystems. A study was conducted under this concept in order toinvestigate the impacts of different fencing periods and measures on plant community complexity in desertgrasslands of Yanchi County of Ningxia Hui Autonomous Region. The study was carried out by using aquadrat method and based on the average length of the Huffman code to describe total complexity L(S),Rényi entropy H(S) as disorder-based complexity, and the difference (S) = L(S)-H(S) as structural complexity.The relationship was also studied between three kinds of complexity index and the number of species,Importance value of dominant species. The results showed that enclosure increases disorder-based complexityindex and structural complexity index, which makes total complexity index to increase. Therefore, fencing isan effective measure for vegetation restoration and rehabilitation while long-term fencing is not conducive tovegetation restoration. In this study disorder-based complexity index is higher than structural complexityindex, which means that disorder-based complexity index has great effects on total complexity index. Therelationship between L(S ) and H(S) is very close whereas the correlation between H(S) and (S) is negative.There is significant relationship between the number of species and the three kinds of complexity index. Theimportance value of dominant species is not significantly correlated with structural complexity, which hassignificant negative correlation with the other indices.
