Directional changes of species spatial dispersion and realized environmental niches drive plant community assembly during early plant succession

Aims Probabilistic models of species co-occurrences predict aggre-gated intraspecific spatial distributions that might decrease the degree of joint species occurrences and increase community rich-ness.Yet,little is known about the influence of intraspecific aggre-gation on the co-occurrence of species in natural,species-rich communities.Here,we focus on early plant succession and ask how changes in intraspecific aggregation of colonizing plant spe-cies influence the pattern of species co-existence,richness and turnover.Methods We studied the early vegetation succession in a six ha constructed catchment within the abandoned part of a lignite mine in NE Germany.At two spatial scales(1-and 25-m2 plots),we compared for each pair of species the intraspecific degree of aggregation and the pattern of co-occurrence and compared observed rela-tionships with temporal changes in important species functional traits.Important Findings The majority of species occurred in an aggregated manner,particu-larly in the first 2 years of succession.In pairwise comparisons,we found an excess of segregated species occurrences leading to a posi-tive link between intraspecific aggregation and pairwise species seg-regation as predicted by the aggregation hypothesis,particularly at the lower spatial resolution.The degree of intraspecific aggregation was negatively correlated with the community-wide level of species spatial turnover and with plot species richness.Our results are the first direct confirmation that increasing intraspecific aggregation and interspecific competitive interactions counteract in shaping plant community structure during succession.The respective effects of aggregation were strongest at intermediate states of early succession.

Conservation and sustainable development in a VUCA world: the need for a systemic and ecosystem- based approach

Targeting the maintenance of functional ecosystems that provide the significant basis for human well-being is an integral part of an ecosystem-based sustainable development.Underlying causes of ecosystem degradation such as global climate change and ever-growing human demands that rapidly shift socioeconomic and political baselines are often unmanageable at a local scale and require a new approach to planning and action in ecosystem management.The framework conditions that challenge sustainable development are shaped by increasing Volatility,Uncertainty,Complexity,and Ambiguity(VUCA concept).Using the MARISCO method(adaptive management of vulnerability and risks at conservation sites),we analyzed 22 conservation sites,covering 26 protected areas and six administrative areas on four different continents and involving 524 participants.VUCA conditions were present across cultures and biomes,yet the responses in planning and management varied among conservation sites.The findings of both the qualitative and quantitative analyses confirm that participants understand how far human well-being heavily depends on the functionality of ecosystems that were seen to suffer from a wide range of stresses and threats of varying criticality.Worldwide,local stakeholders and experts rated impacts of global climate change as most critical.In attempts to achieve ecosystem-based sustainable development,most management teams strive for more risk-robust and adaptive strategies by advocating for active risk management.A common factor identified among all case studies was the need for cooperative management between smaller conservation sites in order to address large-scale challenges.

中亚气候变化:中德合作研究成果

Central Asia(CA)occupies the hinterland of the Eurasian continent,containing the countries of Uzbekistan,Kyrgyzstan,Turkmenistan,Tajikistan,and Kazakhstan[1,2].Being isolated by the Pamir Mountains in Tajikistan,the Tibetan Plateau and the Tian Shan Mountains on the border between China and Kyrgyzstan.