Agricultural opportunity costs assessment based on planting suitability:a case study in a mountain county in southwest China

Payment for ecosystem services(PES) has become an increasingly popular means of ecosystem conservation. Opportunity cost is an important factor to increase the investment efficiency of PES projects.However, the distribution of opportunity cost is usually unclear in mountainous regions due to the obvious environment changes. In this study, we developed a framework to assess the distribution of agricultural opportunity costs in mountainous regions and applied this method to Baoxing County, a typical mountainous county in Sichuan Province of southwest China. Planting suitability of 17 crops was assessed based on agricultural statistics and natural conditions data within a GIS environment.Agricultural opportunity cost was quantified with a weighted summation of farmers' willingness to cultivate and each crop's opportunity cost. Finally,specific agricultural opportunity cost was obtained according to the spatial areas of the protection programs and land use status. The results showed that agricultural opportunity costs of PES in Baoxing County were estimated to be more than $30 million,with a mean of 400.85 $/ha. Agricultural opportunity costs in mountainous regions displayed some obvious spatial variation and areas with lower agricultural opportunity costs could be selected as priority areas for PES. Our findings revealed that the planting suitability evaluation can make agricultural opportunity costs mapping more reasonable. It will be helpful for the PES programs implementation in mountainous regions.

New taxa of Berberis (Berberidaceae) with greenish flowers from a biodiversity hotspot in Sichuan Province, China

A new species,Berberis viridiflora X.H.Li,and a new variety,Berberis sanguinea Franch.var.viridisepala X.H.Li,L.C.Zhang & W.H.Li are described and illustrated from Baoxing County,a biodiversity hotspot located on the eastern edge of Hengduan Mountains in Sichuan Province,Southwest China,Both new taxa resemble B.sanguinea Franch.var.sanguinea,but B.viridiflora differs by the greenish flowers,and the petals being truncate,obtuse,or undulate at apex;while B.sanguinea var.viridisepala differs by the greenish or yellowish green flowers.Morphological features of the pollen grains of B.sanguinea and the two new taxa are revealed by scanning election microscope.B.sanguinea var.sanguinea displays obvious similarities with a sympatric congener,Berberis multiovula T.S.Ying in the morphology of flowers,stems and leaves,especially its ovule number varies greatly from 2 to 9,thus,B.multiovula characterized by the5-ovuled ovary is reduced to a synonymy of B.sanguinea var.sanguinea.On the basis of field surveys and study of herbarium specimens,a total of 16 species and varieties of Berberis are recorded from Baoxing County,and a key is provided.Among the 16 taxa,most phenotypic variations in Chinese Berberis can be displayed,including the habit of plants,most morphological variations of stems,branches and leaves,all types of inflorescences,all color types of flowers,and nearly all types of the shape and color of fruits.Baoxing County and its adjacent Sichuan Giant Panda Sanctuaries possibly constitute an active diversification center of Berberis in eastern Hengduan Mountains of China.