1. Mapping and comparing biodiversity in space is a routine task in ecological research. However, accurate biodiversity mapping requires exact distributional information as inputs. When exact geographical coordinate information is missing or when only coarse distribution of species is available at the quadrat or plot level, how can we effectively infer and compare spatial distributional patterns of species with reasonable accuracy while controlling the confounding impacts of scale dependency? 2. A crossing-scale coefficient of variation (CCV) is calculated for three simple diversity indices, the Shannon, Gini-Simpson and reciprocal-Simpson evenness indices, from the quadrat-based biodiversity data over varying sampling grain sizes for subtly measuring overall spatial distributional pattern of species in a survey map.3. Extensive numerical simulations showed that, when the overall distribution of organisms was regular, CCV tended to be very small, for all the three evenness indices. By contrast, when the distribution was highly aggregate, CCV tended to be large. Finally, an intermediate CCV was observed when organism distribution was random. To this end, all the three evenness indices can detect the subtle change on aggregate or regular distribution. Among the indices, the Gini-Simpson evenness index is the most insensitive to both the change of population size of species and the number of sampling grain sizes used. Compared to available spatial statistic metrics that requires exact geographical coordinates as inputs, CCV is a useful metric for assessing the overall spatial distribution pattern of a species across sampling plots in which exact spatial coordinates of each individual are unavailable. Empirical applications of the CCV metric showed that plants in habitat patches extensively managed by humans can present very aggregate distributional pattern, being counterintuitive to the usual expectation that plants in cultivated or planted land should present regular distributional pattern.4. The present study recommends one effective tool, the combination of CCV and evenness indices, for exploring the overall spatial distributional pattern of a single species under the quadrat-sampling scheme. The proposed method is particularly 972 | Methods in Ecology and Evoluঞon CHEN Et al.
The eastern Qinghai-Tibet Plateau is fragile but offers important ecological services. Because of frequent cutting, local biodiversity is seriously threatened. This makes ecological recovery from logging become a research hot spot. Protozoa as a biological indicator in ecological restoration plays an important role. In this paper, we selected four types of Quercus aquifolioides forests (mature stands, clearcuts for secondary growth aged 20 years, 10 years and 1 year) to study the alteration of soil physicochemical properties and protozoa quantity along different months during growing season. The main results showed that: (1) The amount of flagellates in the second growth forests within 10 years (193 ind./g dry soil) and within 1 year (164 ind./g dry soil) were significantly higher than that in the mature stands (22 ind./g dry soil), while the amount of amoebae was the most in the second growth forest within 1 year (600 ind./g dry soil). Ciliate quantities increased gradually along with the recovery after clearcuts. (2) Protozoa community quantities first showed a significant increase and then decrease with months during the growing season, the abundance of flagellates reach a peak in July, the amount of amoebae was largest in August and ciliate abundance was much greater in •研究报告•
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