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Tim S. Jessop Thomas Madsen M. Jeri Imansyah Heru Rudiharto John A. Phillips 《Biological conservation》2007,135(2):247-255
Species inhabiting archipelagos are often characterised by high levels of interpopulation divergence (e.g. size related traits). This divergence may, in turn, influence their life-history. To facilitate better management and conservation of the Komodo dragon (Varanus komodoensis), an island endemic, we identified demographic differences between two island populations in Komodo National Park, Indonesia. Comparison of data collected from dragon populations inhabiting Rinca Island and the much smaller Gili Motang Island indicated that between 1994 and 2004, the Komodo dragon population on Gili Motang significantly decreased its: (1) mean body mass, (2) body condition and (3) relative abundance. These results suggest that the numerically small Gili Motang population was oscillating downwards; in contrast, the Rinca Island population had been relatively stable. More importantly these results emphasize the necessity for managers of this priority conservation species to understand further the inherent functional differences among dragon populations to develop island specific management units. Current management practices (e.g. monitoring) instigated by Komodo National Park management ignore small island dragon populations and thus run the risk of being unable to detect adverse effects for populations that are potentially most prone to decline. 相似文献
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[目的]采用RAPD技术对圆鼻巨蜥（Varanus salvator）进行遗传多样性分析。[方法]用20个随机引物对圆鼻巨蜥36个个体的基因组DNA进行PCR扩增。[结果]有10对引物能扩出清晰稳定的条带,共扩增出2952条DNA片段,平均每个个体扩增出82个条带,其中47条具多态性,多态性位点比为57.32%,36个个体间遗传距离为0.0359～0.3359,平均遗传距离为0.13592。Neis基因多样性指数H=0.1819,Shannons多样性指数I=0.2630,表明圆鼻巨蜥具有较高的遗传多样性。[结论]采用UPGMA法构建了36个个体相互关系的分子聚类图,发现没有形成明显的种群分化。 相似文献
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[目的]采用RAPD技术对圆鼻巨蜥（Varanus salvator）进行遗传多样性分析。[方法]用20个随机引物对圆鼻巨蜥36个个体的基因组DNA进行PCR扩增。[结果]有10对引物能扩出清晰稳定的条带,共扩增出2952条DNA片段,平均每个个体扩增出82个条带,其中47条具多态性,多态性位点比为57.32%,36个个体间遗传距离为0.035 9~0.335 9,平均遗传距离为0.135 92。Nei s基因多样性指数H=0.181 9,Shannon s多样性指数I=0.263 0,表明圆鼻巨蜥具有较高的遗传多样性。[结论]采用UPGMA法构建了36个个体相互关系的分子聚类图,发现没有形成明显的种群分化。 相似文献
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Eliciting conditioned taste aversion in lizards: Live toxic prey are more effective than scent and taste cues alone 
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下载免费PDF全文 Georgia WARD‐FEAR Jai THOMAS Jonathan K. WEBB David J. PEARSON Richard SHINE 《Integrative zoology》2017,12(2):112-120
Conditioned taste aversion (CTA) is an adaptive learning mechanism whereby a consumer associates the taste of a certain food with symptoms caused by a toxic substance, and thereafter avoids eating that type of food. Recently, wildlife researchers have employed CTA to discourage native fauna from ingesting toxic cane toads (Rhinella marina), a species that is invading tropical Australia. In this paper, we compare the results of 2 sets of CTA trials on large varanid lizards (“goannas,” Varanus panoptes). One set of trials (described in this paper) exposed recently‐captured lizards to sausages made from cane toad flesh, laced with a nausea‐inducing chemical (lithium chloride) to reinforce the aversion response. The other trials (in a recently‐published paper, reviewed herein) exposed free‐ranging lizards to live juvenile cane toads. The effectiveness of the training was judged by how long a lizard survived in the wild before it was killed (fatally poisoned) by a cane toad. Both stimuli elicited rapid aversion to live toads, but the CTA response did not enhance survival rates of the sausage‐trained goannas after they were released into the wild. In contrast, the goannas exposed to live juvenile toads exhibited higher long‐term survival rates than did untrained conspecifics. Our results suggest that although it is relatively easy to elicit short‐term aversion to toad cues in goannas, a biologically realistic stimulus (live toads, encountered by free‐ranging predators) is most effective at buffering these reptiles from the impact of invasive toxic prey. 相似文献
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Tim S. Jessop Joanna Sumner Deni Purwandana John A. Phillips 《Biological conservation》2004,117(5):463-470
We report the abundance, patterns of distribution and physical characteristics of Komodo dragon (Varanus komodoensis) nests on Komodo Island in Indonesia. A total of 46 Komodo dragon nesting sites were identified, of these 26 nests were considered active for the 2002/2003 season. The distribution of nests coincided with large coastal valleys in northern Komodo Island. There was a significant preference by breeding females to utilize the mound nests (61%) over both open hillside (19.5%) and ground nests (19.5%). Further, within these mound nests, females discriminated for nests based on habitat characteristics, especially sunlight exposure. The main implications for management and conservation drawn from this study is that there is a small number of females nesting annually on the largest island within Komodo National Park. Further, continuation of nesting surveys could provide a cost effective accurate way to gather important long term demographic information on this species. 相似文献
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