格氏栲种群增长动态预测研究

以”空间推时间,横向导纵向”方法,建立了格氏栲种群标准生命表、生殖力表,在此基础上运用Ｌｅｓｌｉｅ种群增长模型,预测了格氏栲种群的动态增长过程,揭示了格氏栲各龄级植株的动态规律;同时采用特征根理论方法,分析格氏栲种群稳定性,并模拟格氏栲种群的可能变化．结果表明：该区格氏栲为缓慢增长型种群,总体上保持相对稳定状态,老龄阶段对干扰不敏感,种子和生长阶段对干扰有较大敏感．讨论认为,本结果可为格氏栲种群的保护和经营管理提供理论依据和信息     

单一斜率变点分析格氏栲幼苗的竞争范围

依据改进Hegyi单木竞争模型计算林窗和林下不同龄级格氏栲幼苗的竞争强度,采用指数平滑模型对幼苗竞争强度数据进行优化,对优化后数据应用单一斜率变点法确定格氏栲幼苗最佳竞争范围.结果表明:1)在格氏栲天然林中,林窗和林下格氏栲幼苗平均竞争强度随着竞争距离增大而逐步降低,初期下降较快,下降到一定程度后明显变缓,存在变化幅度的转折点,即为幼苗的竞争范围.2)林窗和林下格氏栲幼苗竞争强度的三次指数平滑值在最佳平滑系数α为0.8和0.7时其均方误差值分别为0.401 5和0.385 1,单一斜率变点分析得出林窗和林下格氏栲幼苗最佳竞争范围分别是距对象木1.70 m和1.90 m.研究结果可为格氏栲幼苗竞争格局研究中确定幼苗竞争范围提供科学理论依据.     

鼎湖山格木种群动态分析

对格木(Erythrophleum fordii)种群的生态环境及生长曲线和种群动态的研究,能揭示其生态特性和种群发展轨迹,对保护、繁殖这一珍稀植物种质具有积极的意义.在对鼎湖山国家自然保护区内的格木群落物种多样性测定的基础上,以国际上通用的CTFS规范对格木群落进行野外调查.文章首次通过对格木种群运用加速单纯形迭代法,逐次把种群数量数据代入6个种群动态模型方程进行拟合分析,得出实际的格木种群动态模型,比较残差平方和、决定系数和F检验显著性概率值,得出格木种群模型的适用度顺序依次为:李新运模型、张大勇模型、宋丁全模型、logistic模型、密度制约模型、崔启武模型.选用李新运模型,确定格木种群大小初始值的精确值N0后,把数据迭代入李新运模型重新拟合,结果显示,拟合优度进一步提高,并且可得知,该格木种群远未达到种群饱和态,而且也没达到种群增长最快处,还处于加速增长状态.故这个时期应该加大保护力度,建立监测体系,以维系格木群落的稳定发展.     

封育次生马尾松(Pinus massoniana)林优势种群竞争密度效应

以退化红壤区封山育林植被恢复过程中优势种群马尾松为研究对象,研究不同恢复阶段马尾松种群竞争密度效应,并提出一个适用性更强的竞争密度效应模型.研究表明,退化红壤区植被恢复过程中优势种群马尾松竞争密度效应明显,优势种群平均胸径(D)、平均胸高断面积(S)、平均单株材积(V)、林分蓄积量 (M)与种群密度 (ρ)的竞争密度关系密切,达到极显著水平(α<0. 01);新竞争密度效应模型较前人模型描述C-D效应效果更理想,可在森林竞争密度效应研究中应用. 表 4参 19     

一种用粪便样方法估计林麝种群密度的新方法

数量(密度)特征是动物种群的一个重要特征，是定点研究一个野生种群生态的一项非常重要的基础工作．其数量和年龄结构为进一步分析其种群的密度、移动、巢域和核域，尤其是为种群动态提供依据，也是珍稀动物保护和资源动物管理利用的先行工作和重要组成部份．关于野生动物种群数量的具体统计方法，有不少的文章报道，然而从动物的空间分布格局来研究大型脊椎动物却较为少见，这主要是受研究方法的限制．为此，作者对此进行了改进，提出了一种新的研究方法：临时空间样方法，并将其应用到冶勒自然保护区林麝的数量调查研究中去．结果表明：(1)集聚分布指数CA=12．09，说明冶勒自然保护区的林麝有较高的集聚度；(2)林麝粪堆在野外的分布属于聚集分布，并与负二项分布拟合较好；(3)在冶勒自然保护区，生活有62～98只左右的林麝，其密度为：1．0～1．6只／km^2．林麝在冶勒自然保护区呈现聚积分布的原因是由于环境和人类活动因素造成的．图1表2参24     

南京南郊马尾松种群动态及种内竞争模型的应用

通过对南京南郊马尾松(Pinus massoniana)种群年龄结构的统计,绘制该种群的静态生命表。结果表明,该马尾松种群年龄结构属衰退型;存活曲线为凸形曲线,属Deevey-A型;死亡率和消失率变化规律一致,均在第11龄级(47~49 a)时取得极大值,分别达0.625和0.981。对群落Hegyi竞争指数的计算表明,种内竞争是马尾松种群衰退的主要原因:种内竞争指数占总竞争指数的85.8%,种内平均单木竞争指数为1.71,而种间竞争指数仅占总竞争指数的14.2%。非线性回归结果表明,用林振山种内竞争模型拟合南京南郊马尾松种群数量的衰退规律可以达到较高优度,判定系数为0.759,此地马尾松种群固有出生率为0.105,环境对马尾松的最大容量为31株·(400 m2)-1。模型稳定性分析表明,马尾松种群虽然处于衰退阶段,但种群不会退出该地区,并将在未来很长时间保持群落优势种的地位,种群密度最终将衰退至9.396株·(400 m2)-1的稳定状态。     

海洋纤毛虫实验生态学研究I：不同浓度葡萄糖对种群增长的影响

为揭示不同碳氮比对纤毛虫种群增长的影响以及纤毛虫对碳源和能量来源的选择性 ,利用实验生态学方法 ,对海水养殖水体中 3种常见的纤毛虫原生动物 :扇形游仆虫 (Euplotesvannus)、海洋尾丝虫 (Uronemamarinum)和巨大拟阿脑虫 (Paranophrysmagna)在牛肉浸膏及梯度浓度葡萄糖培养基中的种群增长过程进行了初步的探讨 .数据分析表明 ,在牛肉浸膏培养基中加入不同浓度的葡萄糖对于纤毛虫种群增长影响显著 ,其中在 0 .0 5 gL-1葡萄糖浓度的培养基中 3种纤毛虫种群增长最佳 (P <0 .0 5 ) ,而在 0 .4 gL-1浓度时纤毛虫的生长繁殖均受到高度抑制 (P <0 .0 5 ) .这一结果显示 ,不同C N比对纤毛虫的种群增长有着直接的影响 .图 3表 3参 10     

西藏色季拉山川滇高山栎种群的空间格局与调节

川滇高山栎是青藏高原具有代表性的常绿阔叶树种,在藏东南林区大面积连续分布,对高山峡谷地带的水土保持和水源涵养具有重要的防护作用和较大的生态效益.采用聚集度指标、以空间推时间法的Logistic方程和种群调节的乘幂函数拟合分别对西藏色季拉山川滇高山栎种群的空间分布格局、增长与调节规律进行了研究.结果表明,川滇高山栎幼苗多呈聚集分布,随着演替的进展,川滇高山栎种群的聚集强度减小;川滇高山栎种群增长的环境容纳量为15.2085m2hm-2,内禀增长率为0.614;种群最大增长速率出现在胸断面积9.66m2hm-2处,种群在平均胸断面积46.23cm2(均胸径7cm)~198.723cm2(均胸径15.91cm)阶段自疏强度最大.川滇高山栎种群聚集强度随演替过程逐渐减弱,是种群在有限的环境容量中自疏和自我调节特征的明显表现.Logistic方程即反映了生物种群增长速度的变化和环境容量限制的时滞效应这一重要特征,种群调节的幂函数拟合则有效刻画了生物种群在大量繁殖之后,随着个体增大,个体间资源竞争增强,种群内部出现优胜劣汰的自我调节过程.图4表2参32     

海洋纤毛虫实验生态学研究Ⅲ:纤毛虫摄食胁迫对弧菌(Vibrio sp.)种群增长的影响

为揭示纤毛虫对弧菌 (Vibriosp.)种群增长的影响 ,利用实验生态学方法对弧菌在海水养殖水体中两种常见的纤毛虫原生动物 ,扇形游仆虫 (EuplotesvannusM櫣ｌｌｅｒ)和海洋尾丝虫 (UronemamarinumDujardin) ,摄食胁迫下的种群增长过程进行了探讨 .数据分析显示 ,弧菌的种群密度在纤毛虫的指数增长期高于对照组 ,但在纤毛虫种群生长平衡期则显著低于对照组 (P <0 .0 5 ) ,在纤毛虫种群生长衰退期则呈回升的趋势 .结果同时还表明 ,海洋纤毛虫的摄食胁迫对弧菌的繁殖具有明显的激活效应 ,但对其种群生长起着显著的抑制作用 .此外 ,本工作也进一步证实了食菌性纤毛虫对改良水质和维持一个健康的养殖环境所具有的积极作用 .图 6参 15     

海洋纤毛虫实验生态学研究Ⅰ:不同浓度葡萄糖对种群增长的影响

为揭示不同碳氮比对纤毛虫种群增长的影响以及纤毛虫对碳源和能量来源的选择性,利用实验生态学方法,对海水养殖水体中3种常见的纤毛虫原生动物扇形游仆虫(Euplotes vannus)、海洋尾丝虫(Uronema marinum)和巨大拟阿脑虫(Paranophrys magna)在牛肉浸膏及梯度浓度葡萄糖培养基中的种群增长过程进行了初步的探讨.数据分析表明,在牛肉浸膏培养基中加入不同浓度的葡萄糖对于纤毛虫种群增长影响显著,其中在0.05 g L-1葡萄糖浓度的培养基中3种纤毛虫种群增长最佳(P< 0.05),而在0.4 g L-1浓度时纤毛虫的生长繁殖均受到高度抑制(P<0.05).这一结果显示,不同CN比对纤毛虫的种群增长有着直接的影响. 图3 表3 参10     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

Representation of the world's biophysical conditions by the global protected area network

Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.     

Quantitative composition of the defensive secretion ofBledius species (Coleoptera: Staphylinidae: Oxytelinae) is adapted to naturally occurring predators

Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.     

Democracy versus development: New urban debates

The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

A framework to measure the wildness of managed large vertebrate populations

As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.     

Sexual Predators,Energy Development,and Conservation in Greater Yellowstone

Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Comparison of the insecticidal effects of water extracted and intact aromatic plants onAcanthoscelides obtectus,a bruchid beetle pest of kidney beans

Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.