Abstract:

Aims Degraded karst ecosystems appear around the world and include the European Dinaric Karst and the South China Karst. The relationship between karst habitats and biodiversity and response to disturbance are essential for karst vegetation succession. Our objective was to study woody plant regeneration in different successional stages in karren-habitats of Yunnan Shilin (Stone forest) Geopark, China.

Methods Based on relationships among karrens, soils and plants, we divided karren-habitats into five types: solution corridors; solution wells or shafts; kluft karren; deep solution pits; and solution rock debris. We sampled seedlings and sprouts of woody species in zonal forest, secondary forest, shrubland, shrub tussock and rocky-desertified grassland that encompass succession in karst plant communities. The Shannon-Wiener, Pielou, Simpson and Margalef diversity indices were calculated.

Important findings The length and width of each karren-habitat was different and the percentage of karren-habitat changed within the five communities and with disturbance intensity. The fruiting species and number of seedlings decreased with karst vegetation degradation, and the number of sprouts reached a maximum in shrubland and decreased respectively toward the zonal vegetation and rocky-desertified grassland. The Shannon- Wiener and Pielou indices for sprouts in the karren-habitat background communities decreased with plant community degradation, and the Simpson index increased. The Shannon-Wiener and Pielou indices for seedlings were highest in shrubland. The seedlings and sprouts in the five kinds of karren-habitats had different values of biodiversity depending on the succession stage. It is inferred that plants of different successional stages have different regeneration strategies. Sprouting plays an important role in the early stages, and seeding is more important toward the zonal plant community. This is partly because some karren-habitats have remains such as stumps and roots of some species that can repeatedly sprout with continuous disturbance. After the disturbance stops, these sprouts can mature and set seed and seedling regeneration can play a major role towards the middle and late stages of succession. The different karren-habitats play different roles in biodiversity conservation and natural restoration of karst plant communities during succession.

Key words: biodiversity, degraded ecosystem, karst, regeneration mechanism, seedling, sprouting, vegetation restoration