Cozad Rebecca A, Hernandez Sonia M, Norton Terry M, Tuberville Tracey D, Stacy Nicole I, Stedman Nancy L, Aresco Matthew J
Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, United States.
Nokuse Plantation, Bruce, FL, United States.
Front Vet Sci. 2020 Mar 5;7:120. doi: 10.3389/fvets.2020.00120. eCollection 2020.
Nokuse Plantation, a 22,055 ha private conservation preserve in northwest Florida, is a recipient site for gopher tortoises translocated from development sites in Florida. Since 2006, Nokuse has received over 5,000 tortoises from multiple development sites. During 2013-2015, 52 tortoises were found sick ( = 14) or dead ( = 38) in multiple soft-release enclosures in which tortoises consistently exhibited clinical signs, with additional sick ( = 5) and dead ( = 5) tortoises presenting similarly during 2016-2017. When found alive, tortoises behaved abnormally (e.g., frequently out of burrows during cold weather, pacing along enclosure fencing), appeared emaciated, were lethargic, and had developed redness under plastron scutes. Similar numbers of male ( = 28) and female ( = 32) tortoises were recovered along with two of unidentified sex, including mainly adults ( = 59) and three subadults. Physical examination, blood analysis, and other diagnostics were indicative of starvation and dehydration. Most sick tortoises provided with supportive care recovered. Necropsy findings generally confirmed starvation, with no evidence of infectious pathogens or contaminants. There were no apparent differences in quality of habitat, plant community, or soil or water among affected and unaffected enclosures. Botanical surveys indicated adequate forage quality and quantity, with no poisonous exotic or native plants detected. No land management practices changed prior to this event. Analysis of epidemiological data and demographic factors from before and during this mortality event identified initial density of tortoises in the enclosures as exerting the strongest influence on detection of tortoise morbidity and mortality. We believe that the stress associated with mixing tortoises from different populations and at higher densities during translocation impacted an individual tortoise's ability to obtain or absorb adequate nutrients from foraging, ultimately leading to a wasting condition consistent with starvation. Based on our findings, we recommend a maximum of 3 gopher tortoises per ha in soft-release enclosures for translocation, but further research is warranted to investigate the complexity of stress and social pressures associated with translocation.
诺库斯种植园位于佛罗里达州西北部，是一个占地22055公顷的私人保护区，也是从佛罗里达州开发地点转移过来的地鼠龟的接收地。自2006年以来，诺库斯已从多个开发地点接收了5000多只地鼠龟。在2013 - 2015年期间，在多个软释放围栏中发现52只地鼠龟生病（n = 14）或死亡（n = 38），在地鼠龟持续出现临床症状的围栏中，另外还有5只生病和5只死亡的地鼠龟在2016 - 2017年期间表现相似。当被发现还活着时，地鼠龟行为异常（例如，在寒冷天气频繁出洞，沿着围栏踱步），显得消瘦、无精打采，并且腹甲盾片下出现发红。回收的雄性（n = 28）和雌性（n = 32）地鼠龟数量相近，还有两只性别不明，其中主要是成年龟（n = 59）和三只亚成年龟。体格检查、血液分析和其他诊断表明存在饥饿和脱水情况。大多数接受支持性护理的生病地鼠龟康复了。尸检结果总体上证实了饥饿，没有感染性病原体或污染物的证据。受影响和未受影响的围栏在栖息地质量、植物群落、土壤或水方面没有明显差异。植物学调查表明饲料质量和数量充足，未检测到有毒的外来或本地植物。在此事件发生之前，土地管理措施没有改变。对此次死亡事件之前和期间的流行病学数据和人口统计学因素进行分析后发现，围栏内地鼠龟的初始密度对检测地鼠龟的发病率和死亡率影响最大。我们认为，在转移过程中，将来自不同种群且密度较高的地鼠龟混合在一起所带来的压力，影响了单个地鼠龟从觅食中获取或吸收足够营养的能力，最终导致了与饥饿相符的消瘦状况。根据我们的研究结果，我们建议在软释放围栏中进行转移时，每公顷最多放置3只地鼠龟，但有必要进一步研究以调查与转移相关的压力和社会压力的复杂性。
