Search

Amphibian populations are under threat worldwide, one such threat is frogs getting trapped in concrete-lined irrigation channels. Earlier studies have found that concrete ditches are acting as barriers to animal movement, fragmenting habitat, and trapping amphibians. China has over 3,000,000 kms of irrigation channels and they are a major threat to frog populations. In this study, we assessed the capacity of a common Chinese frog, Rana nigromaculata , to escape from a typical concrete-lined irrigation channel via 'frog-ways' cut into the walls of the channel. The twelve different designs varied gradients, substrates and widths of the frog-ways. The results showed that these simple and inexpensive retrofits of irrigation channels are very effective at allowing the great majority of frogs to escape. Male frogs were more likely to be trapped in concrete ditches, probably due to their smaller body size. The best design was N11 (55 degree slopes, a crushed stone surface, and 100 cm width) that can help the frogs to successfully escape in just 1 min. Taking water conveyance efficiency of irrigation water delivery systems into consideration, we recommend a longitudinal design (the frog-way is parallel to the water-flow direction) of simple concrete with slopes less than 55° and crushed stone. The findings can serve as a reference for technicians involved in future ecological engineering designs of irrigation channels throughout the world. • A simple and cost-effective frog-way design for irrigation channels • Physical characteristics of frogs and differences in behavioral ability • Capacity of a common Chinese frog to escape from a typical irrigation channel • Effects of different designs with gradients, substrates and widths [ABSTRACT FROM AUTHOR]

Abstract: Soils have an intrinsic ability to adapt to environmental perturbations compounded by global warming and soil pollution to continuously deliver soil functions, but little is known about how a severely degraded soil regains its functional stability after restoration of vegetation. Surface soils were sampled along slopes in a long-term trial where mono Pinus massoniana was transplanted since 1987 on an eroded bare land and pine litter was either protected or removed on the slopes. We hypothesized that litter quantity would drive changes in soil properties rather than soil microbial communities, which would be main factors in controlling soil functional stability. The specific objectives of this study were: 1) to evaluate the effects of litter management on soil properties, soil microbial community structure and functional stability and 2) to explore the relative role of soil properties and microbial community structure in controlling soil functional stability. The functional stability (resistance and resilience) was determined by measuring how the short-term decomposition of added barley (Hordeum vulgare) powder changed over 28-days following copper addition and heating. Community-level physiological profiles (CLPP) and phospholipid fatty acid (PLFA) profiles were measured to characterize soil microbial community structure. Litter quantity was significantly (P < 0.05) and positively correlated with soil organic carbon (SOC) and microbial biomass carbon (SMB-C) concentration, soil structural properties (porosity and aggregate stability) and the resilience to both perturbations. Soil microbial community structure was significantly separated in two different ways. One was associated with the quantity of litter, SOC concentration and its mediated soil properties (SMB and non-capillary porosity). Another was associated with SOC quality and its mediated soil properties (aggregate stability). These biophysical soil properties (SMB, SOC and capillary porosity) were significantly correlated with the resilience to heating and the resistance and resilience to copper addition. The separations of soil microbial community structure driven by litter quality were significantly correlated with the resistance to heating and the resilience to copper addition. This result suggests that the degraded soil could regain its functional stability after re-vegetation due to the concordant development of soil biophysical habitat and soil microbial community structure through continuous organic inputs. Maintaining litter on floor against anthropogenic collection has an important ecological value. [Copyright &y& Elsevier]