Intersexual Conflict and Group Size in <Emphasis Type="Italic">Alouatta palliata</Emphasis>: A 23-year Evaluation

Models of optimal primate group size suggest that group formation and growth arise to benefit individual fitness, but that size is limited by costs. The ecological constraints hypothesis posits that group formation and growth is driven by protection from predation or the advantages of group foraging, while an upper limit on group size is constrained by travel costs and intragroup competition for food or other critical resources. Socioecological models also predict that individual reproductive success, hypothesized to decrease with increasing group size, also places an upper limit on the number of individuals in a group. Our analysis of 23 yr of group composition data on mantled howlers (Alouatta palliata) from a single Panamanian study site on Barro Colorado Island not only corroborates the socioecological model but also shows that female reproductive success increased, whereas that of males decreased, with the less female-biased sex ratios in larger groups. We suggest that the conflict of interest between the sexes over adult sex ratio, particularly the male proportion in a group, in combination with ecological factors, is an important determinant of group size and composition.     

Limited contemporary gene flow and high self‐replenishment drives peripheral isolation in an endemic coral reef fish

Extensive ongoing degradation of coral reef habitats worldwide has lead to declines in abundance of coral reef fishes and local extinction of some species. Those most vulnerable are ecological specialists and endemic species. Determining connectivity between locations is vital to understanding recovery and long‐term persistence of these species following local extinction. This study explored population connectivity in the ecologically‐specialized endemic three‐striped butterflyfish (Chaetodon tricinctus) using mt and msatDNA (nuclear microsatellites) to distinguish evolutionary versus contemporary gene flow, estimate self‐replenishment and measure genetic diversity among locations at the remote Australian offshore coral reefs of Middleton Reef (MR), Elizabeth Reef (ER), Lord Howe Island (LHI), and Norfolk Island (NI). Mt and msatDNA suggested genetic differentiation of the most peripheral location (NI) from the remaining three locations (MR, ER, LHI). Despite high levels of mtDNA gene flow, there is limited msatDNA gene flow with evidence of high levels of self‐replenishment (≥76%) at all four locations. Taken together, this suggests prolonged population recovery times following population declines. The peripheral population (NI) is most vulnerable to local extinction due to its relative isolation, extreme levels of self‐replenishment (95%), and low contemporary abundance.     

千岛湖陆桥岛屿繁殖鸟类的扩散能力差异 对群落动态的影响

岛屿生物地理学理论的核心过程是岛屿物种的周转, 包括迁入与灭绝。本研究旨在探讨扩散能力差异对岛屿繁殖鸟类群落动态的影响。2007年4月至2013年6月, 采用样线法调查了千岛湖36个陆桥岛屿的繁殖鸟类, 依据扩散能力强弱将其划分为两类, 结合陆桥岛屿参数, 并运用逻辑斯蒂回归模型和最大似然法, 来研究鸟类扩散能力的不同对其周转率的影响。结果表明, 千岛湖繁殖鸟类扩散能力强的物种具有较高周转率且受岛屿参数约束较小, 而扩散能力弱的物种周转率较低且对岛屿参数变化更敏感。因此, 千岛湖陆桥岛屿繁殖鸟类的扩散能力显著影响其群落动态。     

Biogeography of dinoflagellate cysts in northwest Atlantic estuaries

Few biogeographic studies of dinoflagellate cysts include the near‐shore estuarine environment. We determine the effect of estuary type, biogeography, and water quality on the spatial distribution of organic‐walled dinoflagellate cysts from the Northeast USA (Maine to Delaware) and Canada (Prince Edward Island). A total of 69 surface sediment samples were collected from 27 estuaries, from sites with surface salinities >20. Dinoflagellate cysts were examined microscopically and compared to environmental parameters using multivariate ordination techniques. The spatial distribution of cyst taxa reflects biogeographic provinces established by other marine organisms, with Cape Cod separating the northern Acadian Province from the southern Virginian Province. Species such as Lingulodinium machaerophorum and Polysphaeridinium zoharyi were found almost exclusively in the Virginian Province, while others such as Dubridinium spp. and Islandinium? cezare were more abundant in the Acadian Province. Tidal range, sea surface temperature (SST), and sea surface salinity (SSS) are statistically significant parameters influencing cyst assemblages. Samples from the same type of estuary cluster together in canonical correspondence analysis when the estuaries are within the same biogeographic province. The large geographic extent of this study, encompassing four main estuary types (riverine, lagoon, coastal embayment, and fjord), allowed us to determine that the type of estuary has an important influence on cyst assemblages. Due to greater seasonal variations in SSTs and SSSs in estuaries compared to the open ocean, cyst assemblages show distinct latitudinal trends. The estuarine context is important for understanding present‐day species distribution, the factors controlling them, and to better predict how they may change in the future.     

Fungal diversity and deterioration in mummified woods from the ad Astra Ice Cap region in the Canadian High Arctic

Non-permineralized or mummified ancient wood found within proglacial soil near the ad Astra Ice Cap (81°N, 76°W), Ellesmere Island, Canada was investigated to ascertain the identification of the trees, current morphological and chemical characteristics of the woods and the fungi within them. These woods, identified as Betula, Larix, Picea and Pinus, were found with varying states of physical and chemical degradation. Modern microbial decomposition caused by soft rot fungi was evident and rDNA sequencing of fungi obtained from the samples revealed several species including Cadophora sp., Exophiala sp., Phialocephala sp., as well as others. Analytical ¹³C-labeled tetramethylammonium hydroxide thermochemolysis showed the lignin from the ancient wood was in a high degree of preservation with minor side chain alteration and little to no demethylation or ring hydroxylation. The exposure of these ancient woods to the young soils, where woody debris is not usually prevalent, provides carbon and nutrients into the polar environment that are captured and utilized by unique decay fungi at this Arctic site.     

缅甸英雄岛始新世-上新世浮游有孔虫及其古环境意义

英雄岛位于印度洋缅甸西海岸,前人在该区所做的工作较少,生物地层研究程度较低.围绕该区石油勘探的进行,作者分析了RM19-3-1井的29件钻井岩屑样品,根据所含浮游有孔虫识别出7次有孔虫生物事件.考虑到研究区处于低纬度地区,故采用Bolli和Saunders(1985)的分带标准建立了7个浮游有孔虫化石带:P12-P17带;P18/19-P21/N2带;P22/N3带,N4-N7带;N8-N10带;N11-N14带和N15-N20?带,其延限时代为始新世-上新世.根据所含有孔虫动物群的演替规律,可将研究区的沉积环境变化由下而上划分为6个阶段,总体具有大陆架-陆坡的沉积环境特征.     

数学模型与自然保护科学

日益加剧的人类干扰和景观破碎化已危及全球的生物多样性。自然保护成为人类所面临的最重要也最富有挑战性的任务。指导这一实践的理论和原则极为需要。本文试图综述与自然保护科学有关的几个学科在理论和实际研究(尤其是模型)方面的近期成果以及发展趋势,从而提出自然保护模型的发展方向。文中涉猎基于不同方法论、不同组织水平的模型,并对数学模型在自然保护科学中的作用和实用性加以讨论。     

Effects of exploitation on reproductive capacity of blackspot snapper, Lutjanus fulviflamma (Pisces: Lutjanidae) in Mafia Island, Tanzania

There is paucity of information on the effects of exploitation on reproductive characteristics of blackspot snapper, Lutjanus fulviflamma (Forsskål 1775) in Tanzanian coastal waters. We compared size at first sexual maturity (L_M50), sex ratio, fecundity, and breeding season of L. fulviflamma in least fished Mafia Island Marine Park (MIMP) and intensively fished areas (IFA) between May 1999 and April 2001. Fish in MIMP matured at significantly smaller size (female: L_M50 = 206.3 mm; male: L_M50 = 195.5 mm) than in IFA (female: L_M50 = 216.7 mm; male: L_M50 =212.1 mm) total body length. Sex ratio was balanced at 1.03 : 1 (female : male) in MIMP, but it was skewed 0.9 : 1 (female : male) in IFA. Size‐related differences in sex ratio were observed with males predominating in the smaller sizes and females in the larger sizes. Total fecundity of fish in MIMP was determined at 45,200–430,200 oocytes in females of between 207 and 293 mm total length. Lutjanus fulviflamma in MIMP has a prolonged spawning season lasting from September to March peaking in December. None of the fish from IFA were in breeding state, suggesting recruitment overfishing is an added matter of concern for the long‐term sustainability of the fishery at the current exploitation level.     

Survivorship of a declining population of southern elephant seals, Mirounga leonina, in relation to age, sex and cohort

This study quantified both the age- and sex-specific survival rates of juveniles and adults, and tested for interannual differences in age-specific survival rates of the southern elephant seal population at Marion Island. Pups were tagged on an annual basis from 1983 onwards at Marion Island, and a consistent recapture program yielded data that was analysed using the software package MARK to obtain maximum-likelihood estimates of survival and capture probability. On average, 1st-year survival was 0.58 and 0.62, and survival rate averaged over the first 3 years of life, 0.69 and 0.74 for males and females, respectively. From years 4 to 9, the average survival rate was 0.66 and 0.75 for males and females, respectively. Survival estimates for elephant seals in their 10th–13th year are also presented, although these are based on very small sample sizes. Averages of age-specific survival estimates from the earlier (mostly 1983–1987 cohorts) and later (mostly 1988–1992 cohorts) periods were compared and considerable reductions were observed in 4th- and 5th-year male survival, and 4th-year female survival. The comparatively low adult survival is suggested as the proximate cause, and food limitation as deduced from the decline in survival of elephant seals with comparatively high energetic demands as the ultimate cause behind the population decline at Marion Island. Although not tied in with the decline of the population, 1987, 1990 and 1993 were identified as high-mortality years. Received: 14 December 1998 / Accepted: 14 June 1999     

舟山渔场金塘岛海域春夏季的鱼类群落

为了揭示金塘岛附近海域渔场鱼类资源特征,利用2009年5月和9月在舟山渔场金塘岛水域获得的渔业资源调查资料,研究金塘岛水域鱼类密度的时空分布,分析种类组成、优势种、种类数和多样性等群落结构等指标的变化特征,分析这些特征所反映这一水域的渔场属性。结果表明:5月和9月鱼类重量和尾数密度分别为47.51kg.km-2、3.44×103ind.km-2和92.50kg.km-2、20.51×103ind.km-2;鱼类重量密度与尾数密度分布趋势基本一致,呈现出近舟山群岛一侧的东部水域鱼类密度高于西部水域的趋势;5月和9月龙头鱼(Harpodon nehereus)是本海域最重要的优势种,几乎为幼体组成,而凤鲚(Coilia mystus)是次要优势种。总体上,两季平均鱼类幼体比例高达86%,显示出这一水域是鱼类的产卵场和育幼场;鱼类种类数夏季高于春季;种类数与多样性的分布格局相似,也是舟山群岛一侧的东部水域鱼类密度高于西部水域。可以认为,近金塘岛一侧海域是经济幼鱼的索饵场。