北美CHIHUAHUAN荒漠啮齿动物群落动态Ⅱ．季节性和周期性

本文利用时间序列分析方法和季节性指标,讨论了北美Ｃｈｉｈｕａｈｕａｎ荒漠由４科１０属１７种啮齿动物组成的群落的物种数、单位面积个体数与生物量、物种多样性的Ｓｈａｎｎｏｎ与Ｓｉｍｐｓｏｎ指数和均匀性等６个变量的季节变动、季节性和周期性。结果表明：（１）每个季节都有变量达到最大值,但除个体数和均匀性外,其余４个变量均在冬季达到最小值;（２）物种数与生物量及两个物种多样性指数之间,以及两个物种多样性指数相互之间有类似的季节变动规律;（３）除个体数外,群落数量动态的其他变量与８个物种种群的密度存在着显著的负相关关系;（４）物种数有最明显的季节性,季节性指标ＳＩ＝０．６２８;（５）物种数、个体数和生物量在９２个月的研究期中未显示出任何周期性。最后总结了该啮齿动物群落动态的时间模式,提出组成物种种群的扩散和休眠行为是形成这些模式的主要原因。     

武汉东湖桡足类的生态学演变

根据１９６２－１９６３,１９７４－１９７５,１９７９－１９９１年在武汉东湖进行的调查资料,考察了过去三十年内在东湖两个代表性采样站桡足类的种类组成及现存量的变化。结果表明：桡足类种类数由６０年代的１４种减少为９０年代的７种,Ｉ、Ⅱ站在种类组成的差别趋于消失。统计结果表明,东湖桡足类现存量以８０年代初、中期较高。但在水平分布格局上却发生了根本变化,由１９８７年前的Ｉ站现存量高于Ⅱ站,至１９８７年后Ⅱ站高于Ｉ站。本文还就影响东湖桡足类演变的生态因子进行了讨论。     

不列颠·哥伦比亚省北部小杆松及白云杉立地指数与生态立地质量的关系

为在ＰｒｉｎｃｅＲｕｐｅｒｔ林区的“亚北方”部分建立生态立地质量与森林生产力的联系,对从９３个小杆松林分和７７个白云杉林分获得的数据进行了分析．所研究的林分处于两个气候状况、８个土壤水分状况以及５个土壤养分状况．这些气候、土壤水分和养分状况被视为等级变量用于林地分类和回归分析．小杆松和白云杉的立地指数随土壤水分和养分状况变化而变化,但不依赖于气候变化．与土壤水分相关的变化格局对两个种来说很相似,但与土壤养分相关的变化格局则全然不同．在所建立的５类回归模型中,土壤小区模型对于两个种都显示出立地指数与土壤水分和养分状况具有很强的相互关系（Ｒ２＞０．８０,ＳＥＥ≤１．６ｍ）．可以认为土壤水分和养分的等级度量在大范围内可作为小杆松和白云杉立地指数的预测预报因子．     

Ecological dominance and the final sprint in hominid evolution

In contrast to many other models of human evolution the “balance of power” theory of Alexander has a clear answer to the question why a runaway selection process for unique social and moral capacities occurred in our ancestry only and not in other species: “ecological dominance” is hypothesized to have diminished the effects of “extrinsic” forces of natural selection such that withinspecies, intergroup competition increased (Alexander, 1989). Alexander seems to be wrong, however, in his claim that already the common HUCHIBO (Humans, Chimps, Bonobo's)-ancestor has crossed the ecological dominance barrier. In this paper an adapted version of Alexander's model is presented and several different ways are proposed to make this adapted version testable. A preliminary survey of the available paleontological and paleoecological data suggests that there is some evidence of a less vulnerable position towards predators in earlyHomo and that there are clear signs related to a crossing of the ecological dominance barrier inHomo sapiens sapiens.     

Forecasting the future suitable growth areas and constructing ecological corridors for the vulnerable species Ephedra sinica in China

Ephedra sinica is a rare and vulnerable species in China, and the habitat of Ephedra sinica is seriously threatened (by climate change and human activities). Predicting the suitable growth areas and constructing ecological corridors for Ephedra sinica in China will help to protect it scientifically. Based on 306 valid distribution records and 13 selected environmental factors, the maximum entropy (MaxEnt) model was used to simulate the potential current habitat zones and future (2050 and 2070) habitat zones of Ephedra sinica under four climate change scenarios. The minimum cumulative resistance (MCR) model was applied to extract important ecological corridors of Ephedra sinica. The results indicate that: (1) Under the current environment, the total area of the suitable habitat for Ephedra sinica in China is 42.24 × 10⁵ km², mainly distributed in Northwest China and North China. (2) Suitable area increases as the RCP rises. The center of mass of the habitat zone moved northward from Shaanxi Province to Ordos City in Inner Mongolia Autonomous Region. (3) Of the 13 environmental factors selected, the primary factor was elevation (20.8 %), followed by wettest month precipitation (18.2 %) and temperature seasonality (15.2 %). (4) Built 19 ecological corridors, with a total corridor length of 430.2 km, including seven long-distance passages and 12 short-distance corridors. All corridors are far from the artificial surface, mostly near high-altitude areas. The 19 ecological corridors constructed using the MCR model will also provide considerable importance for the survival of Ephedra sinica on a longer time scale in the future.     

桃儿七分布格局与生态适应的初步研究

以云南产桃儿七Ｓｉｎｏｐｏｄｏｐｈｙｌｌｕｍ ｈｅｘａｎｄｒｕｍ（Ｒｏｙｌｅ）Ｙｉｎｇ为研究材料,分析了它的分布格局及生态适应。指出桃儿七是一个分布范围较广、生态适应幅度大的物种;在分布区内它主要出现在具有次生植被的山谷中,个体在居群内的分布格局,由于受到放牧活动的影响而呈聚群式分布,植株常出现在灌木丛下和树根附近。它适应夏秋湿润凉爽,冬季及早春寒冷干燥的气候条件,并具有相应的生长与发育节律。人类     

农药对土壤微生物的生态效应

大量有关农药对土壤微生物生态效应的研究表明,虽然有些农药对土壤微生物及其活性会产生抑制或促进作用,但这种作用一般是短暂的;按推荐浓度正常使用农药通常不会影响土壤微生物的各种生化过程和活性,对土壤的物质循环和土壤肥力也没有不利影响;但大多数土壤薰蒸剂和杀真菌剂能改变土壤微生物平衡,它们对土壤微生物的作用强于杀虫剂和除草剂;长期使用农药不致使土壤微生物数量和活性发生明显变化,这应部分归功于土壤微生物对农药的降解或转化．     

淤泥湖退化水生植被恢复及其在湖泊资源天然生态库中作用的研究

对淤泥湖水生植被的天然恢复过程、群落组成、结构、功能与动态等进行了定位研究（１９９２～１９９５）．该湖水生植物共有２０科２９属４１种．４种生活型的植物种类在该湖均有分布,以沉水草本（１５种）和挺水草本（１３种）为多．８个分布区类型中世界广布成分１６种和东亚成分１０种．群落结构包括层次结构和层片结构．该彻共有８个群落类型;群落现存量３２０８．８ｇ·ｍ－２,全湖植被资源贮量为１６３６５．２ｔ．     

Seasonal activity and energetics of two species of varanid lizards in tropical Australia

The field metabolic rates (FMR) and rates of water flux were measured in two species of varanid lizards over five periods of the year in tropical Australia. The energetics of these species were further investigated by directly measuring activity (locomotion) and body temperatures of free-ranging animals by radiotelemetry, and by measuring standard metabolic rate (over a range of body temperatures) and activity metabolism in the laboratory. Seasonal differences in the activity and energetics were found in these goannas despite similar, high daytime temperatures throughout the year in tropical Australia. Periods of inactivity were associated with the dry times of the year, but the onset of this period of inactivity differed with respect to habitat even within the same species. Varanus gouldii, which inhabit woodlands only, were inactive during the dry and late dry seasons. V. panoptes that live in the woodland had a similar seasonal pattern of activity, but V. panoptes living near the floodplain of the South Alligator River had their highest levels of activity during the dry season when they walked long distances to forage at the receding edge of the floodplain. However, during the late dry season, after the floodplain had dried completely, they too became inactive. For V. gouldii, the rates of energy expenditure were 196 kJ kg^–1 day^–1 for active animals and 66 kJ kg^–1 day^–1 for inactive animals. The rates of water influx for these groups were respectively 50.7 and 19.5 ml kg^–1 day^–1. For V. panoptes, the rates of energy expenditure were 143 kJ kg^–1 day^–1 for active animals and 56 kJ kg^–1 day^–1 for inactive animals. The rates of water influx for these two groups were respectively 41.4 and 21.0 ml kg^–1 day^–1. We divided the daily energy expenditure into the proportion of energy that lizards used when in burrows, out of burrows but inactive, and in locomotion for the two species during the different seasons. The time spent in locomotion by V. panoptes during the dry season is extremely high for a reptile (mean of 3.5 h/day spent walking), and these results provide an ecological correlate to the high aerobic capacity found in laboratory measurements of some species of varanids.     

A test for preference of association in a color polymorphic poeciliid fish: laboratory study

Synopsis The ecological and evolutionary forces maintaining genetic polymorphism within populations is of continuing interest to evolutionary biologists. Male pygmy swordtails,Xiphophorus pygmaeus, are polymorphic at a Y-linked locus controlling body color. Fish with the + and cp alleles have blue bodies; those with the con allele have bright gold bodies. Male and female fish were tested in the laboratory to determine if there were any preferences for association with groups of male fish based on color. Single test fish were presented with two groups of males of different phenotypes, and times in which the test fish spent in proximity to each group were recorded. Males of different phenotypes showed no differences in preference, nor did phenotype of the males in the groups affect the behavior of the test fish. Females also showed no preference for males of a particular phenotype. Finally, female test fish showed no preference for groups containing a male with the rare phenotype compared to a group containing all males of the same phenotype.