BEHAVIORAL RESPONSES AND TIME ALLOCATION DIFFERENCES IN DESERT TORTOISES EXPOSED TO ENVIRONMENTAL STRESS IN SEMI-NATURAL ENCLOSURES

IF 1.1 2区 生物学 Q3 ZOOLOGY
D. Ruby, L. C. Zimmerman, S. Bulova, C. Salice, M. O’connor, J. Spotila
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引用次数: 31

Abstract

We tested the effect of water stress on behavior of desert tortoises in semi-natural enclosures. Populations of adult and immature desert tortoises were established at relatively high density in 4.1 ha pens at the Desert Tortoise Conservation Center near Las Vegas, Nevada. Pairs of pens received different levels of food (sod and forb patches) and water supplementation. We postulated that the relatively high densities of tortoises and the different levels of resources created different levels of environmental stress on the populations. Behavior was systematically observed during June-August 1991 and April-September 1992 for differences due to treatment (food and water supplementation versus no food and water supplementation). Behavioral observations were collected during 30 minute focal periods and periodic scan censuses of pens. Animals in the unsupplemented treatments, particularly males, moved further during focal periods than animals with supplemented diets. Movement varied significantly among months. There were no differences in feeding rates among treatments, although monthly effects were important in both treatments. Some differences between years in feeding rates appear related to rainfall patterns and presumably changes in resource availability. Interactions among animals were highest in May and September and were more frequent in unsupplemented pens. Length of morning activity period was shorter in unsupplemented pens for all months. Within treatments, supplemented females were more visible and were seen for longer periods of time during a morning activity period. Home ranges were not significantly different between treatments but showed significant sex effects. Males have larger home ranges than females, and both have larger home ranges than immature animals. When stressed by lack of water and food resources, tortoises reduced the length of above-ground activity time but attempted to compensate for this decreased time by increasing amounts of movement and feeding while active.
半自然圈养环境下荒漠象龟的行为反应和时间分配差异
我们测试了水压力对半自然圈养沙漠象龟行为的影响。在内华达州拉斯维加斯附近的沙漠龟保护中心,以相对较高的密度在4.1公顷的围栏中建立了成年和未成熟的沙漠龟种群。成对的笔得到不同程度的食物(草皮和牧草)和水的补充。我们假设相对较高的龟密度和不同水平的资源对种群造成了不同程度的环境压力。在1991年6月至8月和1992年4月至9月期间系统地观察了由于处理(食物和水的补充与不食物和水的补充)而产生的差异。在30分钟的焦点周期内收集行为观察,并定期对笔进行扫描普查。未补充饮食的动物,特别是雄性,在病灶期比补充饮食的动物移动得更远。不同月份的运动差异很大。两种处理之间的摄食率没有差异,尽管月效应在两种处理中都很重要。不同年份之间摄食率的一些差异似乎与降雨模式有关,可能与可利用资源的变化有关。动物之间的相互作用在5月和9月最高,在没有补充的围栏中更频繁。各组晨起活动时间均较对照组短。在治疗过程中,服用补充剂的女性更显眼,而且在早晨活动期间被看到的时间更长。不同处理间的家谱差异不显著,但存在显著的性别效应。雄性比雌性有更大的活动范围,两者都比未成熟动物有更大的活动范围。当受到缺乏水和食物资源的压力时,陆龟减少了地上活动时间的长度,但试图通过增加活动和进食来弥补这种减少的时间。
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来源期刊
Herpetological Monographs
Herpetological Monographs 生物-动物学
CiteScore
5.40
自引率
0.00%
发文量
2
审稿时长
>12 weeks
期刊介绍: Since 1982, Herpetological Monographs has been dedicated to original research about the biology, diversity, systematics and evolution of amphibians and reptiles. Herpetological Monographs is published annually as a supplement to Herpetologica and contains long research papers, manuscripts and special symposia that synthesize the latest scientific discoveries.
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