四川诺水河珍稀水生动物国家级自然保护区鱼类资源现状

四川诺水河珍稀水生动物国家级自然保护区由嘉陵江支流渠江上游的大通江及支流小通江组成, 为全面了解该保护区的鱼类资源现状, 作者于2015年11月至2017年1月对30个采样点进行了5次资源调查。结果显示, 保护区共分布鱼类57种, 隶属4目13科45属, 其中调查采集47种, 访问调查获得10种。国家二级重点保护鱼类有1种, 即岩原鲤(Procypris rabaudi), 长江上游特有鱼类有12种, 列入《中国脊椎动物红色名录》的易危鱼类3种。保护区以小型鱼类为主, 优势种为宽鳍鱲(Zacco platypus)、嘉陵颌须鮈(Gnarhopogon herzensteini)和切尾拟鲿(Pseudobagrus truncatus)。保护区鱼类多样性较高, Shannon- Wiener多样性指数、Margalef物种丰富度指数、Simpson优势度指数和Pielou均匀度指数分别为2.900、5.198、0.931、0.753。Jaccard相似性系数表明, 大通江和小通江鱼类群落相似度较高, 同一河流不同河段间的相似度整体上与河段间距离成反比; 而不同河流相似海拔高度河段间鱼类群落相似度更高。保护区鱼类资源的衰退主要由过度捕捞、栖息地破坏以及水体污染等人类活动所致。     

太白山森林样地系统发育多样性格局及其影响因素

太白山森林样地系统发育多样性格局及其影响因素 系统发育多样性指数常被用作区分植物群落构建过程中生态和演化过程的相对作用。系统发育多样性格局的推断方法(如系统树的构建和不同的系统发育多样性指数)、演化历史(如生活型)以及环境梯度都可能影响系统发育多样性格局的估计值,进而可能影响我们对植物群落构建过程的认知。因此,有必要区分这些因素如何作用于系统发育多样性格局的估计值,但其相对重要性及其交互作用仍不清楚。本研究利用位于太白山北坡沿海拔分布的20个森林样地(整体高差2800 m左右)的野外调查数据,包括274种木本植物和581种草本植物。对于上述样地内所有植物,我们构建了当前广泛采用的合成树和分子树以比较系统树的构建,特别是合成树末端的多歧分支结构,及其对系统发育多样性格局估计值的可能影响。同时,我们计算了每个样地的3种不同的系统发育多样性指数,包括Faith’s PD, 平均成对距离(MPD)和平均最近类群距离(MNTD),并分别对木本和草本植物进行计算。多模型比较分析系统发育多样性格局的估计值与系统树重建方法、多样性指数、生活型、海拔及其交互作用的最简约关系。研究结果表明,基于合成树和分子树所得到的系统发育多样性格局之间没有显著差异。海拔和多样性指数与生活型在解释系统发育多样性格局方面存在强烈的交互作用,并且能够解释44%以上的变异。系统发育多样性格局的估计值总体随海拔升高而降低,但草本植物相比木本植物变化更平缓。对于木本植物,3种系统发育多样性指数表现出一致的海拔分布格局(即系统发育聚集),而草本植物的平均成对距离指数则表现为随机的海拔分布格局。因此,分析沿环境梯度的系统发育多样性格局需要考虑系统发育格局的推断方法和演化历史的影响,以帮助我们更好地理解植物群落的构建过程。     

北京百花山野生岩生植物资源及其开发利用

对百花山地区的岩生植物资源进行了初步调查。调查结果显示：北京百花山地区的岩生植物资源非常丰富,大约有25科56属74种,其中很多岩生植物不但拥有较高的观赏价值,而且还具有很强的抗性。在此基础上,对这些岩生植物的园林应用价值进行了分析和评价,并对我国野生岩生植物资源的开发利用提出了一些建议。     

百花山野生植物资源分布情况及主要花卉园林应用评价

百花山自然保护区具有优越的地理位置和良好的气候条件,其中孕育着丰富的植物资源,是北京著名的野生花卉种质资源库.在调查分析其野生植物自然分布情况的同时,对其中的重要花卉的潜在园林利用价值作了简要评价,期望加大对百花山野生花卉资源的开发利用.     

秦岭野生常绿针叶植物及其在园林绿化上的应用

通过对秦岭野生常绿针叶植物资源的调查与统计,归纳总结了秦岭野生常绿针叶植物的种类及其分布情况,介绍了部分植物的形态特征、生态习性、园林用途,并提出了开发与利用建议。     

First records of Gastrotricha from South Africa, with description of a new species of Halichaetonotus (Chaetonotida, Chaetonotidae)

During a survey of the biota of the St. Lucia Estuary in the iSimangaliso Wetland Park, South Africa, a number of Gastrotricha were found among samples of meiofauna. Fresh, marine sediment yielded several specimens belonging to a total of seven species. Of these, two are already known from other regions (i.e., Dactylopodola australiensis and Heteroxenotrichula squamosa), one is described as new to science (Halichaetonotus sanctaeluciae sp. n.), while the remaining four (Pseudostomella sp., Halichaetonotus sp.1, Halichaetonotus sp. 2, Xenotrichula sp.) require further collections and analysis, in order to establish the extent of their affiliation to species already described. General appearance, shape of hydrofoil scale and the occurrence of three long spines on the dorsal side make the new species most closely related to Halichaetonotus australis and Halichaetonotus marivagus. The key differences from these taxa and between Halichaetonotus sanctaeluciae sp. n. and Halichaetonotus aculifer are discussed.     

Topographic and ungulate regulation of soil C turnover in a temperate grassland ecosystem

A major obstacle for predicting the effects of climate and land use changes on global soil carbon (C) stores is the very limited knowledge about the long timescale dynamics of the relatively stable fraction of soil C, which represents the bulk of soil C and the primary determinant of the long‐term C balance of terrestrial ecosystems. In this study, we examined how variable topo‐edaphic conditions and herds of native migratory ungulates influenced turnover of the stable pool (total minus active fraction) of soil C in grasslands of Yellowstone National Park (YNP). Soil C properties were determined for grasslands located inside and outside long‐term ungulate exclosures established 1958–1962 at seven variable topographic positions. Active C pool sizes, estimated with soil laboratory incubations, and soil radiocarbon measures were used to parameterize a process‐based model to determine turnover of the stable C pool at the sites. Stable C turnover ranged 37–653 and 89–869 years for 0–10 and 0–20 cm soils, respectively. Among ungrazed communities, there was a trend for stable soil C turnover to slow along topographic gradients of increasing soil moisture, soil C content, and shoot biomass from hilltop to slope‐bottom positions. This was likely a result of an increasing amount of support tissue resulting in greater concentrations of lignin and cellulose as shoot biomass increased down slope. In contrast, across the grazed landscape, stable C turnover sped up from hilltop to slope‐bottom positions, which was likely a consequence of grazer effects on plant species composition along the topographic gradient. These findings indicated that despite topography playing the primary role in controlling such important site characteristics as soil moisture, soil C content, and plant production in YNP grassland, the long‐term turnover of the stable C pool was determined by herbivores. The results demonstrate the important regulatory role of herbivores in controlling the C balance of this semiarid grassland ecosystem.     

Conservation value of low fire frequency in tropical savannas: Ants in monsoonal northern Australia

The conservation values of ‘old‐growth’ forests in landscapes subject to repeated disturbance by fire or logging have received considerable conservation attention. However, little is known of the conservation values of old‐growth sites in ecosystems with an evolutionary history of highly frequent disturbance. Here we address the value of low fire frequency (<1 fire/10 years) in tropical savannas, the world's most fire‐prone biome, in terms of ant biodiversity. We do this by comparing savanna ant communities within the Territory Wildlife Park (TWP) near Darwin in the Australian monsoonal tropics, which has experienced a low incidence of fire over 25 years due to active fire exclusion, with those of adjacent (outside) sites experiencing the ambient fire regime of burning every 2–5 years. Ants were sampled using terrestrial and arboreal pitfall traps at 16 sites, eight each inside and outside TWP. More than 16 000 ants were recorded during the study, representing a total of 98 ant species from 30 genera. More species in total were recorded outside (90) than inside (74) TWP, but there was no difference in mean site species richness or abundance, and overall species composition was similar. All species recorded inside TWP are common and widespread throughout the savanna landscapes of the broader region, in the absence of active fire exclusion. Low fire frequency at the Territory Wildlife Park therefore does not appear to have enhanced regional ant conservation values. Our findings reinforce the importance of targeting fire regimes that are clearly linked to positive conservation outcomes, rather than assuming a need for maximum ‘pyrodiversity’.     

Cytochrome c oxidase subunit 1 barcode data of fish of the Nayband National Park in the Persian Gulf and analysis using meta-data flag several cryptic species

We provide cytochrome c oxidase subunit 1 (COI) barcode sequences of fishes of the Nayband National Park, Persian Gulf, Iran. Industrial activities, ecological considerations and goals of The Fish Barcode of Life campaign make it crucial that fish species residing in the park be identified. To the best of our knowledge, this is the first report of barcoding data on fishes of the Persian Gulf. We examined 187 individuals representing 76 species, 56 genera and 32 families. The data flagged potentially cryptic species of Gerres filamentosus and Plectorhinchus schotaf. 16S rDNA data on these species are provided. Exclusion of these two potential cryptic species resulted in a mean COI intraspecific distance of 0.18%, and a mean inter- to intraspecific divergence ratio of 66.7. There was no overlap between maximum Kimura 2-parameter distances among conspecifics (1.66%) and minimum distance among congeneric species (6.19%). Barcodes shared among species were not observed. Neighbour-joining analysis showed that most species formed cohesive sequence units with little variation. Finally, the comparison of 16 selected species from this study with meta-data of conspecifics from Australia, India, China and South Africa revealed high interregion divergences and potential existence of six cryptic species. Pairwise interregional comparisons were more informative than global divergence assessments with regard to detection of cryptic variation. Our analysis exemplifies optimal use of the expanding barcode data now becoming available.     

Long‐term Changes in Fruit Phenology in a West African Lowland Tropical Rain Forest are Not Explained by Rainfall

Decreases in rainfall have been proposed to have a negative impact on tropical rain forests, and West Africa is currently experiencing a decline in rainfall at the multi‐decadal scale. Here, we present analyses of a long‐term dataset on the plant fruiting status from individuals of 44 species of the tropical rain forest of Taï National Park, Côte d'Ivoire. This study includes records of 1401 individuals collected at monthly intervals for over 12 yr, 984 of which survived throughout the entire study period. The aims of this study were to: (1) quantitate inter‐annual trends in species and forest scale fruit presence; and (2) test the importance of rainfall in explaining inter‐annual fruit presence variability. Long‐term upward trends in the expected proportion of individuals with fruits were found for the majority of species, while no significant downward trends were detected, driving a significant upward trend at the community level. Peak production months of the upward trending species were not associated with the dry or wet season. Significant rainfall correlations with the total proportion of individuals showing fruit were generally negative, with only five species showing significant positive correlations. Taken together, these results suggest that the observed inter‐annual trends and variability of fruit abundance are currently not associated with rainfall. We discuss several parsimonious and complex alternative explanations.