Three new species of the subterranean genus Guiodytes from Guangxi, China (Coleoptera: Carabidae: Clivinini)

Three new species of the genus Guiodytes Tian, 2013 are described from the limestone caves of Guangxi Zhuang Autonomous Region, southern China: Guiodytes weii Huang & Faille sp. nov. and Guiodytes yueliangensis Huang & Tian sp. nov. from Dapo Dong and Huang Dong caves, respectively, in Huanjiang County, northernmost Guangxi; Guiodytes inexpectatus Tian & Zhou sp. nov. from the Zhuzhu Dong cave in Longzhou County, southwestern Guangxi. All of the six known species of Guiodytes are endemic to Guangxi, ranging from the southwest to the northernmost. A modified key to species and a distribution map for Guiodytes are provided.

The Variation in the Stoichiometric Characteristics of the Leaves and Roots of Karst Shrubs

Currently, vegetation restoration is being implemented in the ecologically fragile karst areas in southwest China; however, the stoichiometry of the dominant shrubs and their relationship with the environmental factors in the degraded habitats is still unclear. In this study, we investigated the stoichiometry of C, N, and P, their internal correlations, and influencing factors in 23 shrub species in the Huanjiang County in northwest Guangxi Province, China. We found that the mean contents of C, N and P in leaves were higher than those in roots. In addition, the N:P ratio in the leaves was significantly higher than that in the roots, but the opposite was observed for the C:N and C:P ratios. Except for Leaf C and Root C, significant positive or negative correlations were observed across the stoichiometry of the shrub leaves and roots. A factor analysis of variance demonstrated that the differences across species had higher explanatory power than the topography and soil nutrients in terms of the shrub leaf and root stoichiometry. Hence, our results can improve the understanding of the distribution patterns of these vital elements, as well as of the interactions and influencing factors in the different organs of the karst shrubs.

Rural–Urban Migration and Conservation Drive the Ecosystem Services Improvement in China Karst: A Case Study of HuanJiang County, Guangxi

Under the transformation from over-cultivation to ecological protection in China’s karst, how human activities affect ecosystem services should be studied. This study combined satellite imagery and ecosystem models (Carnegie-Ames-Stanford Approach (CASA), Revised Universal Soil Loss Equation (RUSLE) and Integrated Valuation of Ecosystem Services and Trade-offs (InVEST)) to evaluate primary ecosystem services (net ecosystem productivity (NEP), soil conservation and water yield) in a typical karst region (Huanjiang County). The relationships between human activities and ecosystem services were also examined. NEP increased from 441.7 g C/m2/yr in 2005 to 582.19 g C/m2/yr in 2015. Soil conservation also increased from 4.7 ton/ha to 5.5 ton/ha. Vegetation recovery and the conversion of farmland to forest, driven largely by restoration programs, contributed to this change. A positive relationship between increases in NEP, soil conservation and rural-urban migration (r = 0.62 and 0.53, P < 0.01, respectively) indicated decreasing human dependence on land reclamation and naturally regenerated vegetation. However, declining water yield from 784.3 to 724.5 mm highlights the trade-off between carbon sequestration and water yield should be considered. Our study suggests that conservation is critical to vegetation recovery in this region and that easing human pressure on land will play an important role.

Understanding the Rural Livelihood Stability System: The Eco-Migration in Huanjiang County, China

Immigrants are a special group whose livelihood stability is crucial to local sustainable development. To understand the positive effect of eco-migration policy on the immigrants, we innovatively selected the perspective of stability and quantified immigrants’ livelihood stability with relevant concepts, including livelihood capitals and strategies, response capacity, and land-use efficiency, which helped identify the problems and put forward suggestions to enhance livelihood sustainability, achieve better social integration, and promote the sustainable development of the rural resettlement areas. Huanjiang County was used as a study case as it is the largest and most representative eco-migrant resettlement county of the southwestern karst region, China. Aided by participatory rural appraisal (PRA), this paper explores the livelihood stability of immigrants and takes natives as the reference group. The results show that the livelihood stability values of immigrants were less than that of natives, but the gap was smaller than ten years ago; the natural, social, and other capitals owned by immigrants were almost the same as those of natives, demonstrating that the Chinese government’s poverty alleviation policies have benefitted immigrants. However, both immigrants and natives were found to have less natural and social capitals; high income dependency and an unbalanced proportion of income sources in addition to low land-use efficiency. Therefore, there are several suggestions put forward to achieve stable livelihood and rural sustainable development, and these items should be given increased consideration by both the government and households in resettlement areas.

A review of the aphaenopsian ground beetle genus Uenotrechus Deuve et Tian, 1999 (Coleoptera: Carabidae: Trechinae)

Uenotrechus Deuve et Tian, 1999, one of the highly cave-adapted genera of the ground beetles, is reviewed. New record of the type species U. liboensis Deuve et Tian, 1999 and descriptions and illustrations of two remarkable new species are provided: Uenotrechus gejianbangi Tian et Wei, sp. n. (type locality: Cave Ji Dong, Neiwen Tun, Huanjiang County, northernmost Guangxi), Uenotrechus deuvei Tian et Chen, sp. n. (type locality: Cave Longmu Dong I, Du’an County, northern Guangxi). U. nandanensis bona sp. is proposed as an independent species. A distribution map and a key to all species of Uenotrechus are also given.

Migration and Accumulation of Cadmium in Paddy Soil

Soil samples were collected from a paddy field at Fulong village, Huanjiang County, and Cd concentrations in soils were determined. Soil Cd risk was evaluated using Nemerow index method. The results showed that the content of cadmium in soil layer of 0~20cm is 2 times than the level two standard values and 6 times than the background value of Huanjiang soil. In addition, the soil layer of 20~100cm in cadmium content did not exceed the national level two standard values, but is about 2 times the background value of soil in Huanjiang county. In addition, Cadmium pollution is mainly focused on the soil surface.