阿尔泰山两河源自然保护区森林生态系统朽木生地衣群落的数量分类

应用双向指示种分析和除趋势对应分析对阿尔泰山两河源国家级自然保护区的朽木生地衣群落进行了数量分类。初步结果表明,该自然保护区朽木生地衣共有43种,隶属于5目、14科、20属,它们组成了以下4个地衣群落。群落(Ⅰ):分布在样点1、2、3、4、5中,包括15种地衣种类,命名为对开蜈蚣衣+半羽蜈蚣衣+红心黑蜈蚣衣群落。群落(Ⅱ):分布在样点6、7、8、9、11中,包括25种地衣,命名为尖头石蕊+粉石蕊+矮石蕊群落。群落(Ⅲ):由样点10、12、13、14、16组成,常见的地衣种类有19个种,命名为蜡黄橙衣+茎口果粉衣+冷杉粉衣群落。群落(Ⅳ):包括样点15、17、18、19和20,由22个地衣种组成。命名为疑小梅衣+同色黄烛衣+脱落网衣群落。群落Ⅰ和群落Ⅱ的相似性最高为0.723,其次为群落Ⅰ和群落Ⅲ为0.609,群落Ⅲ和群落Ⅳ之间的相似性最低为0.262。群落Ⅲ的多样性最大为1.954;其次为群落Ⅱ和群落Ⅰ,分别为1.742和我1.685,群落Ⅳ的多样性最低为0.543。各群落的相似性和多样性之间的差异与其所处环境和朽木树种的多样性有关。同时发现在研究地区的朽木生地衣群落的分布与海拔高度、朽木腐蚀程度、朽木大小、森林郁闭度等因子具有密切的关系。     

云居山栓皮栎群落特征及多样性研究

栓皮栎群落是我国暖温带和亚热带落叶阔叶林的重要森林群落类型之一,也是赣北珍稀森林群落之一,在森林演替和植物资源利用中占有重要的地位。通过对江西云居山栓皮栎(Quercus variabilis)群落进行实地调查,采用区系分析、生活型谱分析、物种多样性和双向聚类等方法对其群落特征进行了研究,发现云居山自然保护区栓皮栎群落结构简单,层次明显,多样性程度不高。物种调查及区系研究结果显示,云居山栓皮栎群落维管束植物共计43科56属70种,植物区系主要以泛热带、东亚及北美间断、北温带分布为主,表现出从温带区系向热带区系过渡的特征;生活型谱以高位芽植物为主(占70%),其他生活型相对较少,反映出中亚热带森林以高位芽植物为主的特点。群落物种丰富度、多样性指数均为乔木层小于灌木层和草本层,均匀度指数分析表明,乔木层为聚集分布、灌木层和草本层为均匀分布。双向聚类分析表明,调查的5个样地均为栓皮栎群落,以乔木层物种多度可将5个样地分为3类,组成群落的24个主要物种可分为10类。     

甘肃兴隆山自然保护区马麝夏季栖息地特征及生境选择格局

2006—2008年夏季(7—8月),对甘肃兴隆山自然保护区马麝(Moschus Sifanicus)的栖息地特征和夏季生境选择格局进行了研究。用Mann-Whitney U检验和χ2检验比较了马麝夏季利用生境样地(n=71)和对照性非利用样地(n=264)间的海拔等17个生态变量的差异,结果表明,兴隆山马麝夏季利用生境的郁闭度[(53.87±3.09)%]和乔木均高[(7.57±0.83)m]均显著大于非利用样地[郁闭度:(49.07±1.66)%,乔木均高:(6.33±0.32)m],喜食植物多度[(12.97±1.80)]株也显著大于非利用样地[(9.61±0.67)株]。此外,与非利用样地相比,兴隆山马麝夏季倾向于选择位于中坡位较陡(67.61%)、距离水源较近(<1000m,77.46%)、隐蔽度(88.73%)和避风性均较好(90%)及距人为干扰较远(>1000m,76.06%)的生境;主成分分析结果表明,前4个因子的累积贡献率达72.45%,由乔木胸径和乔木郁闭度变量组成的乔木因子是决定马麝夏季生境选择的首要因素,此外,海拔因子,由地表植被盖度和食物多度组成的食物因子,由灌木盖度、乔木密度和灌木...     

Aspects of community ecology of amphibians and reptiles at Bonny Island (Nigeria), an area of priority relevance for petrochemical industry

Finima Nature Park, situated in Bonny Island (Niger Delta, Nigeria), is a protected forested area placed within one of the most industrially developed (and environmentally polluted) regions of the whole African continent. Amphibian and reptile community composition in relation to season and microhabitat characteristics was studied, by a combination of field techniques, during the wet and dry seasons of 2007 and 2008. Overall, a total of 21 species of reptiles from nine families (with 668 individuals caught) and eight amphibian species from five families (492 individuals caught) were recorded. Nearly 94% of the amphibian individuals and most of the species were recorded, especially during the wet season, whereas most of the reptiles were found with no inter‐seasonal differences. However, Agama agama and Mabuya affinis were found especially during the dry season. As for microhabitat use, the reptile species showed a clear, aggregated preference for two microhabitat types (dry leaves and under logs), which are probably crucial when these animals need to lose body temperature to avoid overheating. Concerning amphibians, the various species used the available microhabitats in a way expectable from their main ecological traits, with toads differing from aquatic frogs, and these differing from arboreal frogs.     

Land Use and Small Mammal Predation Effects on Shortgrass Prairie Birds

ABSTRACT Grassland birds endemic to the central shortgrass prairie ecoregion of the United States have experienced steep and widespread declines over the last 3 decades, and factors influencing reproductive success have been implicated. Nest predation is the major cause of nest failure in passerines, and nesting success for some shortgrass prairie birds is exceptionally low. The 3 primary land uses in the central shortgrass prairie ecoregion are native shortgrass prairie rangeland (62%), irrigated and nonirrigated cropland (29%), and Conservation Reserve Program (CRP, 8%). Because shortgrass–cropland edges and CRP may alter the community of small mammal predators of grassland bird nests, I sampled multiple sites on and near the Pawnee National Grasslands in northeast Colorado, USA, to evaluate 1) whether small mammal species richness and densities were greater in CRP fields and shortgrass prairie–cropland edges compared to shortgrass prairie habitats, and 2) whether daily survival probabilities of ground-nesting grassland bird nests were negatively correlated with densities of small mammals. Small mammal species richness and densities, estimated using trapping webs, were generally greater along edges and on CRP sites compared to shortgrass sites. Vegetation did not differ among edges and shortgrass sites but did differ among CRP and shortgrass sites. Daily survival probabilities of artificial nests at edge and CRP sites and natural nests at edge sites did not differ from shortgrass sites, and for natural nests small mammal densities did not affect nest survival. However, estimated daily survival probability of artificial nests was inversely proportional to thirteen-lined ground squirrel (Spermophilus tridecemlineatus) densities. In conclusion, these data suggest that although land-use patterns on the shortgrass prairie area in my study have substantial effects on the small mammal community, insufficient data existed to determine whether land-use patterns or small mammal density were affecting grassland bird nest survival. These findings will be useful to managers for predicting the effects of land-use changes in the shortgrass prairie on small mammal communities and avian nest success.     

Feeding Ecology of Ring-Necked Pheasant and Northern Bobwhite Chicks in Conservation Reserve Program Fields

ABSTRACT Gamebird chick survival is dependent on invertebrate availability, and the ability to access insect prey is an important characteristic defining brood habitat quality. Different mixes of warm-season grasses and forbs were established to improve the habitat quality of fields enrolled in the Conservation Reserve Program (CRP) for gamebirds in the Southern Plains. We analyzed the feeding ecology of human-imprinted, 4- to 10-day-old ring-necked pheasant (Phasianus colchicus) and northern bobwhite (Colinus virginianus) chicks in wheat fields and 4 types of conservation practices (CP) fields enrolled in CRP (CP10, improved CP10, CP2, and CP25) in western Kansas, USA, during June and July, 2004 and 2005. Foraging rates were greatest for bobwhite chicks in improved CP10 and CP25 fields and greatest for pheasant chicks in CP10 and CP25 fields. Vegetation characteristics such as bare ground cover appear to have a significant impact on insect selection, because the diet was more diverse for both species in fields with more bare ground. The CP25 fields provided the best combination of mobility and diet breadth for both species. Although herbicide-treated wheat fields had low feeding rates, we determined non-herbicide-treated fields (i.e., weedy wheat) provided easy mobility and feeding rates similar to CRP fields. We suggest that management of vegetation to benefit gamebirds does not affect species equally. Feeding rates of bobwhite chicks were sensitive to vegetation-influenced mobility. Management of CRP fields for both pheasant and bobwhite chicks can be reconciled by practices that permit more open space at ground level, such as light disking or burning, to permit easier movement for chicks.     

广东省南昆山伯乐树群落特征及其保护策略

在广东省南昆山自然保护区内调查了中国特有珍稀植物伯乐树种群的分布格局、龄级结构和伴生群落的物种组成.结果表明:该种群的分布范围狭窄且集中;龄级不完整,Ⅱ、Ⅲ级幼树少见,结构呈衰退型;伴生群落呈典型的亚热带植物区系的特点,其组成不稳定、优势种不显著.建议将伯乐树幼树作为就地保护的重点,适当去除周围的罗浮槭、羊角杜鹃和黄樟等速生树种,以创造有光照和水肥条件的生境;对于Ⅳ级以上成株,应注意拟赤杨和华润楠等空间生态位相近树种的数量和密度,适当疏剪枝条,以帮助成株占据较好的空间位;同时再积极引入异龄的伯乐树幼苗,促进种群恢复和发展.     

阳际峰自然保护区地面生苔藓植物分布与环境因子关系研究

在江西阳际峰自然保护区调查的25个样地中,共采集到地面生苔藓植物34科56属106种（包括1变种）。应用CCA排序法,首次定量分析了该区38种主要地面生苔藓植物与环境因子的关系。结果表明,苔藓植物的分布和生物多样性受环境因子的影响较大,湿度、基质是影响地面生苔藓植物分布的主要环境因子,其他影响因子依次为乔木郁闭度、灌木盖度、海拔高度、人为干扰和坡度。     

江西省九岭山自然保护区鱼类资源概况

2007年10月对江西省九岭山自然保护区野生鱼类区系及资源进行了调查.共采集标本952尾,鉴定为39种,隶属于3目12科33属,多为山区溪流小型鱼类.以鲤科鱼类为主, 21种,占鱼类总物种数的53.85%.对各采样溪流进行多样性比较显示,青山站水系(H:3.2)多样性指数最高,和尚坪水系(H:1.9)多样性指数最低;各采样溪流的均匀性指数相差不大(E:0.7～0.9),且优势种群不明显(λ:0.1～0.3).     

Effects of larval host plants on over-wintering preparedness and survival of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

Laboratory colonies of cotton bollworm larvae, Helicoverpa armigera, kept at 20 degrees C under a photoperiod of L:D=10:14 were fed on five host plants (cotton, corn, kidney bean, tobacco and tomato) and an artificial diet (control) to determine the effects of larval host quality on survival and pupal over-wintering preparedness. A separate experiment showed that diapausing pupae weighed more and contained greater nutrient stores than did non-diapausing pupae. Diapausing pupae reared on different host plants showed significant differences in terms of over-wintering reserve storage, and degree of cold-hardiness (extent of low-molecular-weight substances and SCPs), and survivorship. The more nutrients the host plant had, the more the pupae weighed and the higher the levels of total lipids and glycogen. Body water content was also significantly affected by larval food quality. The mean pupal super-cooling capacities varied significantly from -16.7 to -18.9 degrees C according to host plants the larvae feed on, and these significantly related to water content, pupal weight, lipid and glycogen content, and the levels of glycerol. Levels of trehalose, glycerol, and inositol, which were mainly low-molecular-weight substances, showed no significant differences among different host plants, except for trehalose. Pupal mortality varied from 39.7% on corn to 3.3% on the artificial diet, which was significantly related to pupal weight, total lipid content, trehalose levels, and super-cooling points. These results suggest that larval food quality can affect survival and influence the over-wintering preparedness of the cotton bollworm.