鹤山退化草坡生态系统的自然恢复

研究了鹤山南亚热带退化草坡20a的自然恢复动态,发现群落虽有阳生乔木入侵,但仍处于草本和灌丛占优势的生物多样性较低的阶段;土壤中的有机质、水解氮、有效磷和有效钾等营养元素已基本恢复到同地带顶级森林群落的水平;虽然群落的空间结构与生物多样性尚未恢复,但其部分生态功能已经恢复,其中水土保持最先恢复,生产力等功能还需要较长的时间恢复;对于鹤山草坡这类一般退化生态系统来说,可能需要通过构建合适的人工林来加速生物多样性和生物量等指标的恢复过程,仅仅通过自然恢复是难以在较短的时间内迅速恢复其物质循环等功能的。

The natural restoration of degraded rangeland ecosystem in Heshan hill land

This study examined the 20 years trend of natural restoration of a degraded grassland ecosystem in Heshan hilly land.In the past two decades,rangeland research in Heshan has mainly focused on plant succession and soil development.More recently,mechanisms studied have been attempted to explain the initial plant colonization on hilly land,as well as community and ecosystem recovery after disturbance.The results showed that herbs and shrubs were the dominant plants in the community and only a small number of the shade-intolerant tree species had invaded.It showed the characteristics of assembly of pioneer communities.The organic carbon content,soluble nitrogen,available phosphorus,and available potassium had recovered to the level of the local climax community.Part of the ecological functions such as water and soil conservation had recovered.While the functions of water and soil conservation recovered first,more time was needed for productivity and other functions to completely recover,suggesting the idiosyncratic nature of different ecosystem variables in response to time and climate change.Particularly,nutrient cycling recovered very slowly by natural restoration and artificial plantation may be necessary to accelerate the restoration process.