Population dynamics of two sympatric antelope species, grey rhebok (Pelea capreolus) and mountain reedbuck (Redunca fulvorufula), in a highveld grassland region of South Africa

Population dynamics of grey rhebok Pelea capreolus and mountain reedbuck Redunca fulvorufula were monitored at Sterkfontein Dam Nature Reserve in South Africa over three breeding seasons. Birth and death rates were recorded in both species, and causes of death were investigated. Immigration and emigration were monitored in grey rhebok. Grey rhebok bred seasonally, with 91% of lambs being born between November and February. The average fecundity rate was 74% and lamb sex ratios were 22M:19F. Mountain reedbuck also bred seasonally, with a birth peak between October and December. The average fecundity rate was 92%, and lamb sex ratios were 12M:8F. Most deaths in both species occurred between June and November each year. Sixteen grey rhebok deaths occurred during the study, of which 10 resulted from hypothermia during one spring snowfall event. This represented 27% of the population at the time. Males and females were affected to the same degree by the snow, but juveniles suffered more than adults. There was no evidence of infectious disease or predation. Forty-three mountain reedbuck deaths occurred during the study, of which 32 resulted from hypothermia following the snowfall. This represented 51% of the population at the time. Females were affected by hypothermia more than males. There was no evidence of disease in the population from the examination of 41 culled animals, and no evidence of predation. Immigration and emigration within the grey rhebok population were uncommon, but dispersal of yearling males occurred every year between October and December when they were evicted from their natal herds. Herd structure of adult animals was very stable. In mountain reedbuck, emigration was very hard to detect.     

The activity budgets and activity patterns of sympatric grey rhebok and mountain reedbuck in a highveld grassland area of South Africa

Behavioural observations were carried out on grey rhebok and mountain reedbuck at Sterkfontein Dam Nature Reserve, South Africa, for a period of 1 year between May 2001 and April 2002. Four harem herds of grey rhebok, five territorial male mountain reedbuck and female mountain reedbuck (herds grouped as one individual) were monitored to determine activity budgets and activity patterns. Both species spent more time feeding in the late afternoon during relatively cool temperatures, and more time resting in the middle of the day during relatively high temperatures. Statistical comparisons between the two species of the percentage time feeding and resting found no differences between them, although mountain reedbuck spent more time resting overall than grey rhebok. Both species were active at night.     

Territory Quality in Mountain Reedbuck (Redunca fulvorufula chanleri): Distance to Safety

Reedbuck are heavily dependent on cover as a means of evading predators, and Howard (1986a) suggested that males defend cover-abundant habitat in order to maximize access to receptive females which congregate in these areas. We use a measure of female preference for individual territories, and variations in territory size and quality to test this hypothesis in Chanler's mountain reedbuck (Redunca fulvorufula chanleri). Although the amount of cover within each territory did appear to be important, the height of available slope predicted female preference most precisely. It is concluded that, under certain conditions, the extent of available slopes for predator evasion may be a more appropriate indicator of territory quality.     

Climatic influences on the behavioural ecology of Chanter's mountain reedbuck in Kenya

The effects of rainfall and temperature on the behavioural ecology of Chanler's mountain reedbuck (Redunca fulvorufula fulvorufula Rothschild) were examined on ranchland near Gilgil, Kenya. Ambient temperature was shown to be the proximate determinant of diurnal activity and rumination patterns. Mountain reedbuck were active during early morning and late afternoon, but rested and abandoned rumination when temperatures peaked at midday. There was close synchrony in levels of activity, rumination and use of cover and shade between males and females. Seasonal variations in time budgets were strongly influenced by rainfall patterns. Analyses revealed a one-month lag between rainfall and both peak grass growth and a decrease in rumination frequency. The proportion of time allocated to feeding decreased one month later, and was coincident with an increase in the proportion of grass in the diet. Reedbuck may therefore be prevented from exploiting high-quality new grass, possibly by gut-fill or induced imbalances in rumen pH. It is suggested that the unexpectedly high levels of browse in the diet is an adaptive response to low rainfall during the preceding two months.     

Mountain reedbuck Redunca fulorufula growth and age determination using dentition

Lower jaws and measurements were obtained from 473 mountain reedbuck Redunca fulvorufula culled on two reserves in the north-eastern karoo of South Africa. All mandibles were allocated to subjective age classes that were based on tooth-eruption and tooth-wear. In a sample of 69 jaws. the molar and premolar cementum annuli were counted by examining bisected whole teeth under reflected light. One light line appeared to have been deposited per year, and a usable relationship between tooth-wear category and cementum line count was obtained. although indistinct and paired lines often confused the picture. Good correlations were also obtained between the number of cementum lines and the crown height of the first molar (r²= 0.68) and the second molar (r²= 0.77). Actual ages of immatures were estimated by comparing peaks in the distribution in the different age classes with the age since expected mean birth date in different culls. The age of transition to adult dentition (pL 30 months) was determined from two females that were earmarked when young and shot two years later. Von Bertalanffy (1957) growth curves were fitted to measurements of body mass, jaw length and horn length in males to aid field identification of immatures. Asymptotic body mass was reached at 30 months in females and 40 months in males, and asymptotic jaw length was reached at 30 months in both sexes. Horns in males only reached full length at about five years.     

Food habits of Chanler's mountain reedbuck in a Rift valley ranch

During 1971-72 contents from the rumens of twenty-two Chanler's mountain reedbuck (Redunca fulvorufula chanleri Rothschild) collected in the Arthur Cole Ranch near Gilgil, Kenya were examined. Frequency of occurrence of monocots averaged 99.5% of identifiable fragments. Frequency of occurrence of monocots in the ground stratum of the vegetation averaged 94% in the areas where mountain reedbuck were collected. Of the 11 grass classifications (seven to species and four to genus) considered reliably identifiable in rumens, three (Themeda triandra, Hyparrhenia spp., and Cymbopogon pospischilii) were taken more frequently than was expected from their occurrence in the vegetation, six (Aristida spp., Cynodon spp., Eragrostis spp., Harpachne schimperi, Microchlva kunthii, and Tragus berteronianus) were taken less frequently, and two (Bothriochloa insculpta and Enneapogon schimperanus) were taken in approximately the same ratio as they occurred in the ground stratum of the vegetation.     

Karyotype, centric fusion polymorphism and chromosomal aberrations in captive-born mountain reedbuck (Redunca fulvorufula)

Chromosomes of fourteen captive-born mountain reedbucks (Redunca fulvorufula) have been investigated. The diploid chromosome number was 2n = 56 (FN = 60). The mountain reedbuck karyotype consists of 26 acrocentric and two biarmed chromosome pairs resulting from two centric fusions involving chromosomes 2 and 25, and 6 and 10, respectively. In some animals, 57 chromosomes were detected. Variation in the diploid number was found to be due to polymorphism for the centric fusion 6;10. Both X and Y chromosomes are large and acrocentric. The entire Y chromosome and the proximal part of the X chromosome consist of heterochromatin. The chromosomes X, 9 and 14 appeared to be of caprine type. Chromosome aberrations have been detected in two of the 14 animals investigated. A de novo formed Robertsonian translocation rob(6;13) was found in one female heterozygous for the fusion 6;10. CBG-banding revealed one block of centromeric heterochromatin in the de novo formed translocation rob(6;13) and also in the evolutionarily fixed centric fusions 6;10 and 2;25. One examined male homozygous for fusion 6;10, had a mosaic 56,XY/57,XYY karyotype, with 11% of analyzed cells containing two Y chromosomes. The findings were confirmed by cross-species fluorescence in situ hybridization (FISH) with bovine (Bos taurus L.) chromosome painting probes. The study demonstrates the relevance of cytogenetic screening in captive animals from zoological gardens.     

广东省沙溪自然保护区植被资源与分布

文章通过对沙溪自然保护区的植物资源调查,对保护区的植被类型进行了分类,并对野生植物资源的种类的分布进行了分析.调查发现保护区有7种植被类型,其中以亚热带常绿阔叶林为主要植被类型,主要分布于海拔100~850m左右的丘陵和山地.亚热带常绿针叶与阔叶混交林面积较大,主要分布在长坪一带.亚热带常绿与落叶阔叶混交林、亚热带常绿针叶林、灌丛草坡分布较少.竹林主要在村庄附近的沟谷两旁和山地,处于半自然状态.保护区野生维管植物191科630属1225种,其中野生国家级保护植物7种,珍稀野生保护植物7种.保护区内植物资源丰富,其中野生维管植物资源种类繁多,蕴藏量较大,不少种类具有巨大的经济价值和生态价值,这对保护区及北江流域生态环境的保护和改善提供了基础依据.     

Sensitivity of double centrifugation sugar fecal flotation for detecting intestinal helminths in coyotes (Canis latrans)

Fecal analysis is commonly used to estimate prevalence and intensity of intestinal helminths in wild carnivores, but few studies have assessed the reliability of fecal flotation compared to analysis of intestinal tracts. We investigated sensitivity of the double centrifugation sugar fecal flotation and kappa agreement between fecal flotation and postmortem examination of intestines for helminths of coyotes (Canis latrans). We analyzed 57 coyote carcasses that were collected between October 2010 and March 2011 in the metropolitan area of Calgary and Edmonton, Alberta, Canada. Before analyses, intestines and feces were frozen at -80 C for 72 hr to inactivate Echinococcus eggs, protecting operators from potential exposure. Five species of helminths were found by postmortem examination, including Toxascaris leonina, Uncinaria stenocephala, Ancylostoma caninum, Taenia sp., and Echinococcus multilocularis. Sensitivity of fecal flotation was high (0.84) for detection of T. leonina but low for Taenia sp. (0.27), E. multilocularis (0.46), and U. stenocephala (0.00). Good kappa agreement between techniques was observed only for T. leonina (0.64), for which we detected also a significant correlation between adult female parasite intensity and fecal egg counts (R(s)=0.53, P=0.01). Differences in sensitivity may be related to parasite characteristics that affect recovery of eggs on flotation. Fecal parasitologic analyses are highly applicable to study the disease ecology of urban carnivores, and they often provide important information on environmental contamination and potential of zoonotic risks. However, fecal-based parasitologic surveys should first assess the sensitivity of the techniques to understand their biases and limitations.     

湖北后河国家级自然保护区野生花卉资源

后河国家级自然保护区位于鄂西南湘鄂边界山区,野生花卉资源丰富,有"三峡绿宝石"之美誉.笔者分析了保护区的野生花卉资源现状及其开发利用.重点介绍了各类花卉的生物特性和利用的方法.     

Contrasting effects of herbivory on plant size and reproductive performance in two populations of the Critically Endangered species,Euphorbia clivicola R. A. Dyer

Euphorbia clivicola R.A. Dyer is a Critically Endangered Northern Province endemic confined to two populations that have declined drastically over the last decade. One population is protected within a Nature Reserve, while the other occurs in a peri-urban area. In order to determine the causes of the population declines, herbivory damage to plants in both the protected and urban populations was quantified and the effects of herbivory on various aspects of the population biology were assessed. Mountain reedbuck are believed to have been responsible for the herbivory in the protected population. Herbivory on the above-ground branches probably caused the small sizes of protected plants. These were on average less than half the size of urban plants. Herbivory caused a reduction in the number of flowers and fruit produced per protected plant and may have prevented the maturation of flowers into fruit, thereby reducing the total regenerative output of the population. An eight-year absence of fire had resulted in the build-up of a dense moribund grass layer. The selection of E. clivicola plants by mountain reedbuck may therefore have been due to their relatively high nutritional value and accessibility in the thick moribund grass layer. Fencing off the population to prevent entry of herbivores, and implementing a more suitable fire management programme is recommended, as is the adoption of a new IUCN status for the species of Critically Endangered (CR A1).     

Helminth parasites of the tropical gar, Atractosteus tropicus Gill, from Tabasco, Mexico

A total of 8 helminth species were recorded in an examination of 43 tropical gar, Atractosteus tropicus Gill, collected at the Pantanos de Centla Biosphere Reserve, Tabasco, Mexico. The parasite species included 1 adult trematode, 3 metacercariae, 1 cestode, 1 adult nematode, and 2 nematode larvae. Six of these 8 species were rare, with low prevalence (< 17%) and abundance (< 1.0 helminths per examined fish). The larvae of Contracaecum sp. were the most abundant in the sample, constituting 60% of the total helminths (64% prevalence, 3.8 +/- 5.2 abundance), followed by the cestode Proteocephalus singularis, constituting 18% of the worms (30.5% prevalence, 1.1 +/- 3.0 abundance). Species richness, individual parasite abundance, and diversity were low in the infracommunities. The recording of 3 specialist species in the tropical gar confirms that the helminth fauna of gar has an appreciable degree of specificity. This study indicates the importance of ecological determinants of richness in helminth communities of the tropical gar.     

内蒙古赛罕乌拉自然保护区狼的数量分布和食物组成

2006年1月至2008年12月,在内蒙古赛罕乌拉国家级自然保护区运用样线法和粪便分析法,对狼(Canis lupus)的生态分布和食物组成开展了研究。研究结果:保护区狼的数量至少7只,密度为(4.18±2.88)只/100km2,主要分布于保护区的圣山和庆云山核心区。在圣山主要活动于山脊、道路和沟谷;在庆云山主要活动于山脊。草兔(Lepus capensis)和植物在狼的食物组成中出现率最高,其食物组成在年度间存在显著差异(P<0.01),冬春与夏秋季节间差异不显著(P>0.05)。     

Experimental transmission of gastro-intestinal nematodes between sheep (Ovis aries) and Thomson's gazelles (Gazella thomsonii).

Experimental cross-transmission of gastro-intestinal nematodes between Merino sheep (Ovis aries) and Thomson's gazelles (Gazella thomsonii) from similar but separate grazing habitats in Kenya was studied. Cross-transmission did occur with some species but the faecal egg counts of sheep were higher than the gazelles' following infection with larvae isolated from either sheep or gazelles. Of the 11 gastro-intestinal nematodes which became established in gazelles following infection with larvae cultured from nematodes in gazelles, only Haemonchus contortus, Trichostrongylus probolurus and Cooperia hungi were infective for sheep. Following infection with larvae of either sheep or gazelle origin, the H. contortus recovered from the sheep at necropsy were more numerous and had greater average weights, lengths and spicule lengths than those recovered from the gazelles. This would suggest that H. contortus is primarily a sheep parasite. It is concluded that Thomson's gazelles probably would not contribute significantly to the problem of haemonchosis in sheep in areas of shared grazing, unless efforts were being made to eradicate the parasite from sheep, in which case the gazelles would act as a continuing reservoir of infection.     

贵州省蛇类新记录——赵氏后棱蛇

2010年8月和2018年5月于贵州省雷山县(雷公山国家级自然保护区,1号标本)、贵州省黄平县(朱家山县级自然保护区,3号标本)和麻江县(1号标本)共采集到5号游蛇科Colubridae后棱蛇属Opisthotropis标本,经形态学和分子系统学分析鉴定为赵氏后棱蛇Opisthotropis zhaoermii,这是该种在模式产地湖南省古丈县外的首次发现。线粒体cyt b序列构建的系统发育树显示,5号赵氏后棱蛇(武陵山系以西)和模式产地(武陵山系以东)的聚为一支;遗传距离计算结果显示,5号赵氏后棱蛇与模式产地的为0.08%;分子遗传学结果表明,赵氏后棱蛇分布于武陵山系东、西两侧。武陵山系的余脉(如佛顶山)对赵氏后棱蛇不同地理种群的遗传分化可能起着重要影响。     

河漫滩湿地生态阈值——以二卡自然保护区为例

以典型河漫滩湿地 —— 二卡自然保护区为研究区域,进行生态阈值研究。根据湿地补给河流 —— 海拉尔河的月均流量频率分布特征,选取58.72 m³/s(P=74.6%)、119.26 m³/s(P=44.4%)、190.35 m³/s(P=23.8%)分别代表河流的低、中、高径流期,分析各径流期湿地分布特征。结果表明,低、中径流期内草本沼泽及盐化沼泽所占比例较高,而高径流期则以季节性河流湿地及湖泊湿地为主。低径流期内,作为湿地中心区的湖泊湿地景观破碎度出现一个较明显的跃变,由中径流期的0.57增加到1.37。此时的湿地状态可近似的作为区域的生态阈值,即维持湿地面积占全区域面积的43.03%。而中、高径流期湿地面积比例可近似作为保护区湿地面积的适宜值和理想值,分别为53.66%和69.53%。其研究结果为二卡自然保护区的管理及保护提供支持,并为河漫滩湿地研究提供思路。     

Polystomatidae (Monogenea) of southern African Anura: Polystoma claudecombesi n. sp. parasitic in Rana angolensis Bocage

Polystoma claudecombesi is described as a new species of the Polystomatidae (Monogenea) parasitic in the urinary bladder of the anuran host Rana angolensis. This parasite was collected at three localities in South Africa, namely Vernon Crookes Nature Reserve in Natal province, Witsieshoek Mountain Resort in the north-eastern Orange Free State and Bovenste Oog in the province of Transvaal. It is the largest African polystome described to date. Prevalence at Vernon Crookes Nature Reserve was 4.0% and 2.7% in two successive years, with a mean intensity of 1.0 (n=25 and 36, respectively). One of the two R. angolensis from Witsieshoek was infected with 5 parasites. The diversity and distribution of southern African polystomes is also discussed.     

Effects of season and physical condition on the gastrointestinal helminth community of white-tailed deer from the Texas Edwards Plateau

Eighty-six adult female white-tailed deer, Odocoileus virginianus (Zimmermann), collected over a 12-mo period in the Texas Edwards Plateau, harbored six species of nematodes (Haemonchus contortus, Gongylonema pulchrum, Oesophagostomum venulosum, Ostertagia ostertagi, Cooperia sp., and Apteragia odocoilei), and two cestodes (Moniezia sp. and Taenia hydatigena). The patterns of distribution of the three common species of gastrointestinal helminths (H. contortus, O. venulosum, and G. pulchrum) were overdispersed. When analyzed for the main and interactive effects of the extrinsic and intrinsic variables of season and physical condition, respectively, aggregated abundances in H. contortus and O. venulosum appeared to result from the main effect of seasonal changes operating over the collective populations of these two species rather than from the intrinsic factor of physical condition operating within selected subpopulations. Abomasal parasite counts do not appear to be a useful index for monitoring herd condition of white-tailed deer from this geographic region.     

新疆阿尔泰山曲尾藓科2个中国新记录种

阿尔泰山是欧亚大陆最为宏伟的山脉之一,其中段的西南坡坐落于中国新疆境内,众多具温带性质的藓类植物分布于此。作者在对阿尔泰山进行苔藓植物区系调查过程中,发现了分布于阿尔泰山的喀纳斯自然保护区及布尔津县禾木乡的2个藓类植物中国新记录种——隶属曲尾藓科的短叶曲尾藓[Dicranum brevifolium(Lindb.)Lindb.]和卷叶小曲尾藓[Dicranella crispa(Hedw.)Schimp.]。由地理分布可知,短叶曲尾藓和卷叶小曲尾藓在中国皆为稀有种类。