喀斯特石漠化的研究现状与存在的问题

喀斯特石漠化是土地荒漠化的主要类型之一。 喀斯特生态系统的脆弱性决定了喀斯特生态系统的易损性和退化喀斯特生态系统的难恢复性，但它与发生石漠化并没必然的联系，喀斯特石漠化是岩溶生态系统退化的结果，而不是喀斯特生态系统脆弱性的必然表现。故所指的喀斯特石漠化，特指人为加速的石漠化，属于人为荒漠化的一种类型，但强调喀斯特石漠化的人为成因性，并不是否定自然背景对喀斯特生态系统的制约作用。石漠化土地的分类既要能反映出石漠化发生的严重程度，也要能体现石漠化土地的成因和岩性地貌等地质背景对生态学过程的影响，因此，作者提出以“土地利用类型+植被+岩性+地貌+石漠化程度”对人为加速石漠化过程中石漠化土地进行类型划分，以正确评价石漠化土地的生态环境价值。

岩溶生态系统的土壤特性及其今后研究方向

岩溶石漠化退化土地是目前西南岩溶地区经济发展、生态恢复与重建工作中严重的问题之一。由于岩溶生态系统的独特性和脆弱性, 岩溶生态系统土壤具有不同于其它生态脆弱区土壤的特征, 本文将其归纳为成土速率决定的在人类活动尺度下土壤不可再生性即脆弱性、土壤侵蚀(土层丢失) 的独特性、土壤退化过程中空间分布的斑块化及其与岩性的相关性、土壤退化过程中有机碳活性成分下降和来源变化、土壤退化导致岩溶生态系统生态过程中断。因此, 在退化岩溶生态系统的研究中, 要加强对岩溶生态系统土壤特性及退化恢复理论的研究。

黔中喀斯特地区的景观变化及其生态效应

为了解喀斯特地区景观变化过程及相应的生态效应,利用遥感影像数据对黔中地区1995 —2000 年的景观格局与动态进行分析。结果显示:研究区以灌木林地、坡耕地、中覆盖度荒草地占据着景观中的优势地位。旱地、林地和荒草坡的转换关系复杂,退耕还林还草与毁林毁草开荒同时并存,植被恢复与退化并存,整体景观尚处于一种波动状态,区域土地利用生态价值并未有明显提高,而呈下降趋势。研究区景观格局特征是岩性、地貌和人为活动共同作用的结果,景观斑块的转化主要受人文因素的影响,耕地的变化主要是被建设用地占用。在1995 —2000 年的土地利用变化中,研究区的生态既有恢复,又存在继续恶化的趋势。

岩溶生态系统脆弱性剖析

生态系统的脆弱性评价对于生态系统管理具有重要作用。在分析岩溶生态系统脆弱性特征和影响因素的基础上,构建了针对岩溶自然系统的脆弱性评价指标体系,涵盖了岩溶生态系统的结构脆弱性、生态过程脆弱性、生态功能脆弱性和人为胁迫脆弱性4个方面,评价指标分别是结构稳定性、多样性生境、能量利用和积累、直接使用价值、石漠化程度和速率等。以不同类型的原生岩溶生态系统的生态基准值作为比较基础,评价系统将现有的退化岩溶生态系统的脆弱性划分为轻微脆弱、中度脆弱、重度脆弱以及系统崩溃4级

不同干扰条件下社会认知偏离者两半球协同功能研究

Previous studies have witnessed some psychological or behavioral deviation (such as aggressive behavior) might have an association with cerebral hemisphere cooperative dysfunction, however, it is still unclear whether there is an association between individuals with social cognitive bias and their hemispheric cooperative functions especially while the interhemisphere cooperative processing is under the conditions of emotional interferences. The purpose of this study is to explore the differences between the social cognitive bias group and the normal group’s interhemispheric cooperative functional activity under the conditions of with or without interferences. Methods: According to Dodge’s (1993) model of “social-cognitive mechanisms in the development of conduct disorder and depression”, a 51 items of “social cognitive bias scale” was created and was used to screen the high score group. 20 male subjects was composed of high score group and other 23 matched the control group. Stimulus tachistoscopically presented to the bilateral visual field and compared with the central. Both group’s interhemispheric cooperative functional activity were observed and compared under the conditions of without interference- i.e. base level and with the emotional interferences of white noise level and negative evaluative feedback speech level while finishing: experiment one: Chinese word-figure Stroop analogue task; experiment two: two single Chinese Characters combination task. Heart rate and respiratory rate were simultaneously recorded as index of emotional changes. Results: ① The high score group showed a decrease in processing accuracy compared with the normal group under the condition of white noise interference level in experiment one. ② Still under the condition of white noise interference level, there were more reaction time and more errors were observed in high score group than normal in experiment two. ③ Both groups showed speed up effect and the strategic processing tendency of speed-accuracy trade-off effect under the condition of white noise interference level in both experiments. ④ Between group differences of interhemipheric cooperative function were not observed under the conditions of base level and the negative evaluative feedback speech level within both experiments. Conclusion: The results suggested that interhemispheric cooperative functional differences exists between the two groups, characterized as ① differences existed in interhemispheric cooperative processing strategy between the two groups, with the high score group presented “hierarchic” deficiency strategy. ② the appearance of the differences between the two groups were condition specified , and in this research it was only under the white noise interference condition. ③ the features of the differences between the two groups were the differences on multidimensional performances and with a deficit orientation in high score group. ④ the varieties of the differences were changing with cooperative tasks, as in this research the high score group performed worse in complementary cooperative task. In addition, both group adjusted the processing strategy respectively under the condition of white noise evoked emotional interference implied that the interaction between the interhemisphere cooperative processing and emotion might exist.