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首页> 外文期刊>Chelonian conservation and biology >Crowding Affects Health, Growth, and Behavior in Headstart Pens for Agassiz's Desert Tortoise
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Crowding Affects Health, Growth, and Behavior in Headstart Pens for Agassiz's Desert Tortoise

机译：拥挤影响了Agassiz沙漠乌龟的启迪笔的健康，生长和行为

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Worldwide, scientists have headstarted threatened and endangered reptiles to augment depleted populations. Not all efforts have been successful. For the threatened Agassiz's desert tortoise (Gopherus agassizii), one challenge to recovery is poor recruitment of juveniles into adult populations, and this is being addressed through headstart programs. We evaluated 8 cohorts of juvenile desert tortoises from 1 to 8 yrs old in a headstart program at Edwards Air Force Base, California, for health, behavior, and growth. We also examined capacities of the headstart pens. Of 148 juveniles evaluated for health, 99.3% were below a prime condition index; 14.9% were lethargic and unresponsive; 59.5% had protruding spinal columns and associated concave scutes; 29.1% had evidence of ant bites; and 14.2% had moderate to severe injuries to limbs or shell. Lifetime growth rates for juveniles 1-8 yrs of age were approximately two times less than growth rates reported for wild populations. Tortoises in older cohorts had higher growth rates, and models indicated that high density in pens and burrow sharing negatively affected growth rates. Densities of tortoises in pens (205-2042/ha) were 350-3500 times higher than the average density recorded in the wild ( 1/ha) for tortoises of similar sizes. The predominant forage species available to juveniles were alien annual grasses, which are nutritionally inadequate for growth. We conclude that the headstart pens were of inadequate size, likely contained too few shelters, and lacked the necessary biomass of preferred forbs to sustain the existing population. Additional factors to consider for future reptilian headstart pens include vegetative cover, food sources, soil seed banks, and soil composition.
机译：在全球范围内，科学家们率先采取了濒临灭绝的爬行动物，以增加枯竭的人口。并非所有的努力都成功。对于濒临灭绝的阿加西兹沙漠龟（Gopherus agassizii），恢复的挑战之一是向成年人口招募未成年人，这已通过开端计划解决。我们在加州爱德华兹空军基地的一项启动计划中评估了8个年龄在1到8岁之间的青少年乌龟的健康，行为和生长状况。我们还检查了启动笔的容量。在评估的148名青少年的健康状况中，有99.3％的人处于基本状况指标以下； 14.9％的人嗜睡且无反应； 59.5％的人有脊柱突出和相关的凹形凹槽； 29.1％的人有被蚂蚁叮咬的迹象； 14.2％的四肢或贝壳受到中度至重度伤害。 1-8岁少年的终生增长率约为野生种群报告增长率的两倍。年龄较大的队列中的乌龟具有较高的增长率，模型显示，高密度的笔和洞穴共享对增长率的负面影响。围栏中的乌龟密度（205-2042 /公顷）比类似大小的乌龟在野外记录的平均密度（<1 /公顷）高350-3500倍。少年可获得的主要牧草种类是外来一年生草，其营养不足，无法生长。我们得出的结论是，启迪笔的大小不足，可能没有太多的遮蔽物，并且缺乏维持现有种群所需的首选福布斯所需的生物量。未来的爬虫类爬行动物要考虑的其他因素包括植被，食物来源，土壤种子库和土壤成分。

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