Characterizing the spatial distribution of giant pandas (Ailuropoda melanoleuca) in fragmented forest landscapes

Aim To examine the effects of forest fragmentation on the distribution of the entire wild giant panda (Ailuropoda melanoleuca) population, and to propose a modelling approach for monitoring the spatial distribution and habitat of pandas at the landscape scale using Moderate Resolution Imaging Spectro‐radiometer (MODIS) enhanced vegetation index (EVI) time‐series data. Location Five mountain ranges in south‐western China (Qinling, Minshan, Qionglai, Xiangling and Liangshan). Methods Giant panda pseudo‐absence data were generated from data on panda occurrences obtained from the third national giant panda survey. To quantify the fragmentation of forests, 26 fragmentation metrics were derived from 16‐day composite MODIS 250‐m EVI multi‐temporal data and eight of these metrics were selected following factor analysis. The differences between panda presence and panda absence were examined by applying significance testing. A forward stepwise logistic regression was then applied to explore the relationship between panda distribution and forest fragmentation. Results Forest patch size, edge density and patch aggregation were found to have significant roles in determining the distribution of pandas. Patches of dense forest occupied by giant pandas were significantly larger, closer together and more contiguous than patches where giant pandas were not recorded. Forest fragmentation is least in the Qinling Mountains, while the Xiangling and Liangshan regions have most fragmentation. Using the selected landscape metrics, the logistic regression model predicted the distribution of giant pandas with an overall accuracy of 72.5% (κ = 0.45). However, when a knowledge‐based control for elevation and slope was applied to the regression, the overall accuracy of the model improved to 77.6% (κ = 0.55). Main conclusions Giant pandas appear sensitive to patch size and isolation effects associated with fragmentation of dense forest, implying that the design of effective conservation areas for wild giant pandas must include large and dense forest patches that are adjacent to other similar patches. The approach developed here is applicable for analysing the spatial distribution of the giant panda from multi‐temporal MODIS 250‐m EVI data and landscape metrics at the landscape scale.     

相岭山系大、小熊猫主食竹类峨热竹的生长发育与环境因子间的相互关系

1994～1996年,在相岭山系冕宁县治勒自然保护区设点,对大熊猫和小熊猫主食竹类峨热竹与其它环境生态因子间的相互关系进行了长达3a的研究。研究结果表明,峨热竹的生长发育与环境生态因子如海拔、郁闭度、坡度和坡向之间有极其显著的相关关系,环境因子对其株高、基径、密度、发笋率、老笋比例和成竹死亡率等有较大的影响。随海拔高度的增加,竹子变矮变细,老笋比例下降;上层乔木郁闭度增加,竹子变稀,发笋率、老笋比例和成竹死亡率均降低。坡度增大,竹子变稀并且细而矮。阳坡的竹子率发笋高于阴坡。     

Female giant panda (Ailuropoda melanoleuca) chirps advertise the caller's fertile phase

Although female mammal vocal behaviour is known to advertise fertility, to date, no non-human mammal study has shown that the acoustic structure of female calls varies significantly around their fertile period. Here, we used a combination of hormone measurements and acoustic analyses to determine whether female giant panda chirps have the potential to signal the caller''s precise oestrous stage (fertile versus pre-fertile). We then used playback experiments to examine the response of male giant pandas to female chirps produced during fertile versus pre-fertile phases of the caller''s reproductive cycle. Our results show that the acoustic structure of female giant panda chirps differs between fertile and pre-fertile callers and that male giant pandas can perceive differences in female chirps that allow them to determine the exact timing of the female''s fertile phase. These findings indicate that male giant pandas could use vocal cues to preferentially associate and copulate with females at the optimum time for insemination and reveal the likely importance of female vocal signals for coordinating reproductive efforts in this critically endangered species.     

Genomic Signatures of Coevolution between Nonmodel Mammals and Parasitic Roundworms

Antagonistic coevolution between host and parasite drives species evolution. However, most of the studies only focus on parasitism adaptation and do not explore the coevolution mechanisms from the perspective of both host and parasite. Here, through the de novo sequencing and assembly of the genomes of giant panda roundworm, red panda roundworm, and lion roundworm parasitic on tiger, we investigated the genomic mechanisms of coevolution between nonmodel mammals and their parasitic roundworms and those of roundworm parasitism in general. The genome-wide phylogeny revealed that these parasitic roundworms have not phylogenetically coevolved with their hosts. The CTSZ and prolyl 4-hydroxylase subunit beta (P4HB) immunoregulatory proteins played a central role in protein interaction between mammals and parasitic roundworms. The gene tree comparison identified that seven pairs of interactive proteins had consistent phylogenetic topology, suggesting their coevolution during host–parasite interaction. These coevolutionary proteins were particularly relevant to immune response. In addition, we found that the roundworms of both pandas exhibited higher proportions of metallopeptidase genes, and some positively selected genes were highly related to their larvae’s fast development. Our findings provide novel insights into the genetic mechanisms of coevolution between nonmodel mammals and parasites and offer the valuable genomic resources for scientific ascariasis prevention in both pandas.     

秦岭中段南坡景观格局与大熊猫栖息地的关系

景观格局是各种生态过程在不同尺度上作用的结果 ,同时景观格局强烈影响着生境内种群的生物学过程 ;种群的结构和分布状况同栖息地景观格局之间存在一定的联系。借助遥感和地理信息系统软件 ,对秦岭中段南坡地区 3个保护区 (佛坪、长青和观音山 )大熊猫栖息地的景观格局及其与大熊猫活动痕迹密度之间的关系进行了研究。该研究首先绘制了景观类型格局图并进行总体斑块格局分析 ,其次分别从保护区尺度和 1km2 尺度分析平均斑块分维数、破碎度指数和香农多样性指数 ,以进行比较 ;最后在 1km2尺度上统计分析大熊猫活动密度同景观格局指数分布的相关性。研究结果表明 :(1)各自然保护区内的景观格局存在着差异性 ,佛坪保护区景观多样性水平较高 ,长青保护区居中 ,观音山保护区最低 ;(2 )各保护区内部受人为干扰和生境恢复程度不同 ,使得景观破碎化程度在佛坪保护区最低 ,长青保护区居中 ,观音山保护区最高 ;(3)大熊猫活动密度有集中分布的趋势 ,高密度区域主要分布在佛坪中部和长青北部 ;(4 )在 1km2尺度 ,3个保护区大熊猫活动痕迹密度同景观指数格局之间存在不同的相关性 ,说明不同的景观格局会影响到大熊猫的活动和生境利用。     

秦岭大熊猫栖息地巴山木竹生物量

巴山木竹是秦岭大熊猫冬、春季食物的主要来源,其生长状况、数量和空间分布格局与大熊猫的生存与活动有着密切的关系。为了探讨不同立地因子对巴山木竹生物量的影响,确定巴山木竹生长的主导因子和适宜立地条件,在秦岭大熊猫栖息地内选取54块样地,对不同立地条件下巴山木竹生物量进行了测定。通过统计分析,结果表明:由于不同地区气候和土壤条件的差异,导致了巴山木竹生物量亦存在较大差别;巴山木竹生物量在其分布区内随海拔的升高而呈规律性变化,1500—1700 m为最适分布区域,其生物量最大;坡度越大生物量越小,陡坡不适宜竹林的生长;上坡位不利于竹林生长,而中、下坡位生物量没有显著差异;坡向对生物量的影响不明显,均适宜巴山木竹生长;在落叶阔叶和针阔混交林中,当林冠郁闭度>0.6时,竹林生长减弱。在这些立地因子中,影响巴山木竹生物量积累的主导因子是坡位和林冠郁闭度。     

圈养大熊猫种群的动态及发展趋势

采用直线回归方程、4次方程和指数增长式微分方程等数理分析方法,对全世界1953～2003年圈养大熊猫种群的发展趋势进行了分析.发现对大熊猫的圈养种群数量建立的回归方程是拟合很好的4次多项式方程,1953～1987年的圈养种群增长曲线成S型,1998年后的种群增长成直线或指数式.依此进行预测,从1998年以后只依靠现有饲养种群167只就可能使种群数量稳定增长,全世界种群数量2007年可突破200只,2009年可能达到220～240只,大概在15～22年后全世界饲养种群数量就能够翻一番,达到330多只.     

Behavioral preferences for bamboo in a pair of captive giant pandas (Ailuropoda melanoleuca)

Giant pandas (Ailuropoda melanoleuca) are members of the order Carnivora. Their diet, however, consists almost entirely of bamboo. Herbivores are under strong pressure to be selective in what they eat because of the low digestibility of plant material. The purpose of this study was to determine whether two captive giant pandas exhibited preferences among three species of bamboo: black (Phyllostachys nigra), bissetii (Phyllostachys bissetii), and arrow (Pseudosasa japonica). Eighteen classic choice trials were conducted in which the species were randomly paired and placed in one of two predetermined locations in the giant pandas' indoor enclosures. The pandas preferred leaves to culms or branches for each bamboo species. In the first hour of exposure, both pandas exhibited a preference for arrow bamboo. A comparison of total bamboo consumption over the course of the night indicated a strong preference for arrow bamboo by the male. The female exhibited equal preference for both arrow and bissetii over black bamboo. Further examination of feeding behavior determined that the pandas processed arrow bamboo behaviorally more efficiently than the other two species. This is the first study to experimentally assess bamboo preferences in giant pandas, and may have implications for husbandry and management programs as well as strategies for in situ conservation. Zoo Biol 24:177–183, 2005. © 2005 Wiley‐Liss, Inc.     

小熊猫妊娠期粪便中孕酮、雌二醇的水平变化

2000年3—8月在成都动物园和成都大熊猫繁育研究基地,用放射免疫分析法测定了6只雌性小熊猫粪样中孕酮（P）和雌二醇（E2）的水平变化,同时对其繁殖行为进行了观察。研究结果表明,交配后的雌体粪样中E2浓度下降至基础水平,P浓度在30d后上升至150ng／g以上;怀孕雌体在妊娠期粪样中P水平在200ng／g以上,P峰值可以达500ng／g以上;假妊娠者粪样中P水平一般不超过150ng／g,P峰值在200ng／g以下;雌体产前半个月孕酮迅速下降,E2缓慢上升,产后P保持在基础水平。这意味着可通过测定粪便中P水平进行早孕诊断、产期预测和真假妊娠判断。根据行为观察和粪样激素分析可知,雌兽妊娠期为123—128d（X=124,N=5）,产仔率为1．8／胎（N=5）。