Elk Survival and Mortality Causes in the Blue Mountains of Washington
Elk Survival and Mortality Causes in the Blue Mountains of Washington
复制标题
华盛顿蓝山麋鹿的生存和死亡原因
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Pat E. Fowler
中科院分区：
文献类型：
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作者：
S. McCorquodale;Paul Wik;Pat E. Fowler
摘要
我们研究了生存的麋鹿（马鹿）≥ 1岁，并量化死亡率的来源在蓝山的华盛顿，2003-2006年，经过一段时间的广泛偷猎。种群管理在一个只有穗的一般狩猎季节，与较大的男性和女性有限的许可证。我们放射标记190麋鹿（82名男性和39名女性>1岁，65名男性11个月大），大多数与瘤胃发射器和颈部无线电项圈; 60麋鹿只接受瘤胃发射器。我们估计年生存率使用已知的命运模型，并探讨性别和年龄组之间的生存差异，并在2个潜在的不同脆弱区的男性。我们发现很少支持年轻（2-3岁）和老年（≥4岁）的分支鹿角男性之间的生存差异或一岁男性的区域差异。具有分支鹿角雄性动物区域差异的模型是排名第二的模型，占可用模型权重的14%。根据最佳支持模型，我们估计一岁雄性的年生存率为0.41（95%CI：0.29-0.53）。我们估计合并成年女性生存率为0.80（95% CI：0.64-0.93）;当纳入年龄组效应时，壮年女性的点估计值（2-11岁：S = 0.81 [0.70-0.88]）高于老年女性（≥12岁：S = 0.72 [0.56-0.83]），但置信区间广泛重叠。7个模型中只有1个模型存在女性年龄对生存率的影响，属于竞争模型。对于分支鹿角的男性，生存范围为0.80-0.85，这取决于区域变化是否建模。我们记录了78例放射性标记麋鹿的死亡。人为死亡（n = 55）是主要原因，其中大多数是在国家批准的狩猎期间被杀的一岁雄性（n = 28）。大多数亚成年男性死亡部落狩猎（n = 5），和大多数成熟男性死于自然原因（n = 6）和部落狩猎（n = 5）。我们发现了一些非法杀害（n = 4）。我们的研究结果表明，加强执法有效地减少了偷猎，未报告的部落收获是不是一个微不足道的死亡率来源，穗只有一般的季节是有效的招募分支鹿角男性。
ABSTRACT
We studied survival of elk (Cervus elaphus) ≥ 1 yr old and quantified mortality sources in the Blue Mountains of Washington, 2003–2006, following a period of extensive poaching. The population was managed under a spike-only general hunting season, with limited permits for larger males and for females. We radiomarked 190 elk (82 males and 39 females >1 yr old and 65 males 11 months old), most with rumen transmitters and neck radiocollars; 60 elk only received rumen transmitters. We estimated annual survival using known fate models and explored survival differences among sex and age classes and in 2 potentially different vulnerability zones for males. We found little support for differences in survival between younger (2–3-yr old) and older (≥4-yr old) branch-antlered males or zone differences for yearling males. A model with zone differences for branch-antlered males was the second ranked model and accounted for 14% of the available model weight. From the best-supported models, we estimated annual survival for yearling males at 0.41 (95% CI: 0.29–0.53). We estimated pooled adult female survival at 0.80 (95% CI: 0.64–0.93); when an age-class effect was included, point estimates were higher for prime-aged females (2–11 yr: S = 0.81 [0.70–0.88]) than for older females (≥12 yr: S = 0.72 [0.56–0.83]), but confidence intervals broadly overlapped. Only 1 of 7 models with a female age effect on survival was among the competitive models. For branch-antlered males, survival ranged 0.80–0.85, depending on whether zone variation was modeled. We recorded 78 deaths of radiomarked elk. Human-caused deaths (n = 55) predominated among causes and most were of yearling males killed during state-sanctioned hunts (n = 28). Most subadult male deaths were from tribal hunting (n = 5), and most mature males died from natural causes (n = 6) and tribal hunting (n = 5). We detected few illegal kills (n = 4). Our results suggest that increased enforcement effectively reduced poaching, that unreported tribal harvest was not a trivial source of mortality, and that spike-only general seasons were effective in recruiting branch-antlered males.