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In 1997, we conducted a vegetation survey in three semi-arid natural grasslands (steppes) with different livestock grazing intensities in Southwest Heilongjiang Province, China. The dominant grassland species was the grass Stipa baicalensis Roshev. Grasslands with light, intermediate, and heavy grazing intensities were located 10, 5, and 2 km from a village, respectively. Villagers use the steppe to raise cattle, horses, sheep, and goats. Each of the three grasslands was surveyed by placing 100 quadrats (50 cm×50 cm) along a 50 m line transect. Each quadrat was divided into four equal areas (25 cm×25 cm; S-quadrats) and all plant species occurring in each of these smaller areas were identified and recorded. These data were summarized into frequency distributions and the percentage of S-quadrats containing a given species and the variance of each species were estimated. The power law was applied to these estimates. The power law was used to evaluate the spatial heterogeneity and frequency of occurrence for each species in the grassland community. The lightly grazed grassland exhibited high spatial heterogeneity (caused by large plant size), the highest species diversity, and a high occurrence of S. baicalensis. In contrast, the heavily grazed grassland exhibited high spatial heterogeneity (caused by patchy populations of small plant size), low species diversity, and a low occurrence of S. baicalensis. We judged that the heavily grazed grassland was overgrazed and exclusion of livestock from the degraded areas is necessary for recovery.

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Vegetation in the northwestern mountainous region of Guangdong Province, China is a mosaic of forests and shrubs. Shrubs in this area are evergreen with heights <2.5 m and have been left unused for at least 50 years. Recently, light grazing by a local breed of goats was started in a mountainous region near Lechang City under local government guidance. We conducted a survey over 4 years to estimate plant mass as a feed resource for goats in a sharply undulating mountainous shrubland. Two permanent plots (50 × 50 m) were set in a 76‐ha site; shrub‐dominated downward slopes and valleys (S plot), and a mountain ridge and an adjacent slope dominated by herbaceous species on slightly poorer soil (G plot). The plant mass, including herbaceous plants, and leaf and xylem parts of shrubs, which were determined through allometric equations based on measurements of breast height diameter of shrubs, was estimated at 15.9 t dry matter (DM) ha−1 in the S plot and 7.7 t DM ha−1 in the G plot. The total mass of herbaceous plants and shrub leaves, available to grazing goats, was estimated at 3.9 and 3.1 t DM ha−1 in the S plot and G plot, respectively. We conclude that 4.9 adults and 2.4 kids ha−1 can be stocked throughout a year on this mountainous shrubland.

Fish is one of the most important nutrition sources for humanity. Contaminant exposure risk in fish farming will eventually deliver to the crowd through diet. China is the largest fish producing as well as exporting country, where mariculture plays an important role in fish production, especially in South China. Previous investigations indicated that a variety of compartments in farming areas of South China Sea were polluted by persistent organic pollutants, including DDT (dichlorodiphenyltrichloroethane) and its derivatives, some of which is designated as DDTs. In the present study, Hailing Bay and Daya Bay of Guangdong Province, China, were selected as the study sites and DDTs as the target compounds. A fish enrichment model was developed to assess the relative contributions of various pathways to the mass loadings of DDTs in the fish. Average concentrations (and concentration ranges) of DDTs in various environmental compartments of Hailing Bay and Daya Bay were included in modeling and analysis. Modeling results indicated that fish food and seawater contributed approximately the same proportions for the DDTs in maricultured fish. Antifouling paint was supposed to be the primary source of water DDTs in mariculture zone of Hailing Bay and Daya Bay, which contributed 69 % of the total DDTs to the mariculture water. We suggest that in order to protect people from consuming highly contaminated maricuture zone fish, the most effective and feasible methods are using environment-friendly antifouling paint and applying less polluted fish food in the fish reproduction process.

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The Xilingol steppe, located in Inner Mongolia, northern China, is a natural grassland well known for producing high‐quality feed for grazing animals. Our regression analysis using the meteorological data recorded at the Xilingol Meteorological Observatory from 1953 to 2000 (48 years) indicated that the annual mean temperature rose by 2.66°C during 50 years from 1953, while the mean temperature during the plant growing season (April–October) rose by 2.10°C during the same period. These temperature rises at the Xilinhot Observatory are more than twice that found in other regions of China. In the same 48‐year period, no significant changes in annual precipitation amounts were noted; however, the annual precipitation days significantly decreased. We must clarify the factors causing climate change in this region and how such change will impact future productivity and biodiversity in this semiarid grassland.