接种基枝藻培养绿毛龟的试验

本试验分别采用了打磨龟背、营养液浸泡和奈乙酸溶液浸泡的处理方法。结果表明,奈乙酸溶液可使“冒绒”速度大大加快;奈乙酸对基枝藻孢子囊形成和孢子释放能起到促进作用,其适宜浓度为0.1～5ppm。     

温室无沙养鳖工艺的初步研究

温室无沙养鳖法是对传统的有沙养鳖进行重大改革，其主要特点是能克服底质和池水极易污染的问题，从而改善栖息环境，提高放养密度。“人工鳖巢”是一种较理想的栖息隐蔽物，有它替代河沙，排污比较彻底，洗池省工省时。试验证明，无沙养鳖法具有高产、优质、低成本，以及观察检查，饲养管理和干池捕鳖均很方便等优点。这种新工艺对稚鳖和幼鳖都适用，但它是一项综合性的养殖技术，除用“人工鳖巢”替代河沙作鳖的栖息隐蔽物外，在饲     

光合细菌(PSB)和翻富(FAMP)在温室无沙养鳖中的应用研究

一般的温室养鳖存在着鳖池底质和水质容易污染的问题，净化处理费工耗能；无沙养鳖新工艺可以妥善解决这一难题。本试验通过四个处理组──有沙、无沙、无沙＋ＰＳＢ、无沙＋ＦＡＭＰ──进行对比，显示出无沙养鳖法具有节能、低耗、高产、优质等特点。光合细菌（ＰＳＢ）对改善水质，提高鳖的产量有一定作用，但在较好的水质环境条件下其作用不明显。翻富（ＦＡＭＰ）为新型饲料添加剂及水质改良剂，在本次试验中增产效果亦不明显。     

Agricultural practices alter sex ratios in a reptile with environmental sex determination

Anthropogenic changes to the environment have the opportunity to impact natural systems, particularly in organisms that exhibit phenotypic plasticity. Species with environmental sex determination (ESD) are uniquely susceptible to changes in the stimuli that affect sexual development, potentially leading to maladaptive sex ratios. We studied the factors affecting sex determination and sex ratios in the common snapping turtle, Chelydra serpentina, in an area heavily impacted by agricultural practices. We investigated the effects of soybean, corn, and sunflower planting on incubation temperatures, sex ratios, and depredation in naturally laid nests. We also identified and analyzed a novel mitochondrial microsatellite in order to examine the presence of natal homing and determine the likelihood that nest sites impacted by agricultural practices could be transmitted across generations. Females frequently chose to nest in agricultural fields over sand prairie sites, and offspring sex ratios and depredation rates were significantly influenced by crop planting. Despite detecting considerable genetic variation in our population, we found no relationship between relatedness and nesting location, suggesting that females are not transmitting nesting sites across generations. Our results suggest that agricultural practices can directly impact populations of animals with ESD, and will need to be considered in management decisions.     

基于林氏系统语言的树木枝条分形特征模拟1

基于树木分枝的分形特征,在简要介绍林氏系统语言基本概念和海龟解释基础上,应用L-studio软件编写林氏系统语言程序对不同枝条的分枝类型进行生长模拟,并通过引入随机性因子使得应用林氏系统生成的树木分枝图形更加丰富多彩和形象逼真。林氏系统可对树木枝条仿真和树冠动态生长可视化模拟提供参考。     

基于林氏系统语言的树木枝条分形特征模拟

基于树木分枝的分形特征，在简要介绍林氏系统语言基本概念和海龟解释基础上，应用L—studio软件编写林氏系统语言程序对不同枝条的分枝类型进行生长模拟，并通过引入随机性因子使得应用林氏系．统生成的树木分枝图形更加丰富多彩和形象逼真。林氏系统可对树木枝争仿真和树冠动态生长可视化模拟提供参考。     

Vital rate sensitivity analysis as a tool for assessing management actions for the desert tortoise

Sensitivity analyses of population growth in desert tortoise (Gopherus agassizii) have shown no consensus on the limiting vital rate. More importantly, the most sensitive vital rate might not be the most readily manipulated by management, so it begs the question of what actions would be most effective. We compared 13 management alternatives using a vital rate sensitivity analysis that is valid regardless of age structure, and is sensitive to initial population size and time frame, to determine the efforts required for equivalent population growth. We evaluated three time frames, each with five initial population sizes and three initial age distributions. To achieve equivalent population growth, mortality of older females needed to be reduced less than did mortality of other age classes. Similarly, fewer adults needed to be introduced to a population to have the same effect as releasing juveniles, but differences among adult age classes were trivial. A single release (headstarting) required fewer total individuals than did annual releases to achieve the same population growth. Also, the same population growth was more easily achieved when the initial age structure was deficient of young animals. Interestingly, because small tortoises are difficult to survey, some management alternatives could result in increased population size but decreased numbers of countable individuals over short to intermediate (25 years) time frames. Our paper demonstrates an approach to determine what constitutes equivalent management actions for population growth, thus allowing managers to more directly compare expected gains toward population recovery achieved by their resource-allocation decisions.     

L系统理论及其应用综述

L系统是虚拟植物研究的重要方法。本文描述了L系统的基本特征、图形解释含义,阐述了各类L系统的基本概念:D0L系统、随机L系统、上下文关联L系统、参数L系统、微分L系统和开放式L系统。对L系统在国内的应用进行了全面介绍。     

Modeling loggerhead sea turtle (Caretta caretta) interactions with US Mid-Atlantic bottom trawl gear for fish and scallops, 2005–2008

Interactions between sea turtles and northwestern Atlantic trawl fisheries are of global concern, and the National Marine Fisheries Service is considering expanding bycatch reduction regulations, including deployment of turtle excluder devices (TEDs). To inform bycatch mitigation strategies, the number of loggerhead sea turtle (Caretta caretta) interactions was estimated for US Mid-Atlantic bottom trawl fisheries for fish and scallops. A generalized additive model of interactions was developed using 1994–2008 Northeast Fisheries Observer Program data from trawl fisheries that were not required to deploy TEDs. Predicted loggerhead interaction rates were applied to 2005–2008 commercial fishing data to estimate the number of interactions for the trawl fleet. For trawl fisheries in which TEDs were required, an experimentally-determined TED exclusion rate (97%) was applied to estimate the number of loggerheads that were excluded by TEDs. Latitude, depth, and sea surface temperature (SST) were associated with the interaction rate. Average annual interactions for 2005–2008 were estimated at 292 (CV 0.13, 95% CI 221–369) loggerheads, with an additional 61 (CV 0.17, 95% CI 41–83) excluded by TEDs. The interaction rate was highest south of latitude 37°N in waters <50 m deep with SST >15 °C; interaction magnitude in terms of adult equivalents was highest at latitude 37–39°N, depth <50 m, and SST >15 °C. Predicted average annual loggerhead interactions decreased compared to 1996–2004, likely due to decreased commercial fishing effort in high-interaction areas. Additional sea turtle conservation measures can be informed by the high-interaction-rate and -magnitude areas identified through this analysis.