Integrated plant diversity hotspots and long-term stable conservation strategies in the unique karst area of southern China under global climate change

Abstract

The Karst Areas in Southern China are known for their abundant plant diversity and high endemism, but confronted with unprecedented challenges in biodiversity conservation. To identify hotspots and evaluate conservation effectiveness and gaps of the areas we built an occurrence database containing 16,073 species with 344,179 distribution points. We identified plant diversity hotspots by employing the top 5% richness algorithm, complementary algorithm and spatial phylogenetics, and evaluated the conservation effectiveness and gaps of hotspots under current conservation network by consideration spatial distribution ranges of both. Then, we conducted correlation analysis of distribution patterns and predicted suitable habitat areas of threatened species. Hotspots identified in this study are of high value in conservation priority for 75 hotspot grid cells scattered in 9 periphery regions of the karst areas and harboured 78.70% species only with 5% area. Conservation effectiveness analysis indicated that there were 38, 27 and 48 hotspot grid cells protected by either national nature reserves (NNRs), provincial nature reserves (PNRs), or both. These protected cells contained 59.28%, 49.08% and 64.76% of all species, respectively. However, conservation gaps analysis showed that 37, 48 and 27 hotspot grid cells were located outside of the conservation networks of NNRs, PNRs, or both, as they contained only 65.63%, 70.98% and 59.53% of all species. Further analysis of the conservation status of different taxa showed a high proportion of regional endemic and threatened species shared by hotspots and conservation gaps, which may be due to high percentage of narrow-ranged species occurring in both. More attentions should be paid to strengthen conservation networks and create new conservation areas to address the apparent gaps. Targeted conservation planning should also focus on hotspot distribution patterns of specific plant taxa to address the mismatches of distribution patterns of different taxa as indicated by different algorithms. Other countermeasures, for example, dynamic monitoring and rearrangement of the conservation network, should be envisaged in the future. The current and future suitable habitat areas are mostly confined to the heartland of karst areas, while the identified hotspots of plant diversity are much more limited, and especially under climate change scenarios the karst biodiversity will face huge challenges.