We assessed the effectiveness of an extensive and unprecedented wildlife reduction effort directed at a wide‐ranging migratory population of geese. Population reduction efforts that targeted several populations of light geese (greater snow geese [Chen caerulescens atlantica], lesser snow geese [C. c. caerulescens], and Ross's geese [C. rossii]) began in 1999 in central and eastern North America. Such efforts were motivated by a broad consensus that abundance of these geese was causing serious ecological damage to terrestrial and salt marsh ecosystems in central and eastern parts of the Canadian Arctic and subarctic regions along Hudson Bay. Starting in February 1999, special conservation measures (or, in the U.S., a conservation order) were added to the respective federal regulations that permitted hunters to take snow geese (in parts of Canada and the U.S.) and Ross's geese (in parts of the U.S.) during specified harvest periods outside of the hunting season. These measures were accompanied by increase or removal of daily kill and possession limits and by permissions to use previously prohibited equipment for hunting these species in certain regions of the continent. The intent was to reduce adult survival through increased hunting mortality, which was judged to be the most cost‐effective approach to reversing population growth. Our principal goal was to assess the effectiveness of reduction efforts directed at the midcontinent population of lesser snow geese, which was thought to be the most serious threat to arctic and subarctic ecosystems of the 3 light goose populations. Our multiple objectives included the estimation and detection of change in the response measures of total annual harvest, harvest rate, survival rate, and abundance, using the 1998 hunting period (defined as 1 Aug 1998 to 31 Jul 1999) as a point of reference. We used information about hunter recoveries of leg‐banded snow geese and estimates of regular‐season harvest to estimate 1) conservation‐order harvest and total annual harvest, 2) geographic and temporal distribution of recoveries by age class, 3) survival and recovery probability, and 4) abundance of snow geese each August using Lincoln's (1930) method. We also modeled population growth to infer the form of population response to management efforts. Toward that end, we also proposed a method of estimating conservation‐order harvest and tested for differences in band‐reporting rate between Canada and the United States. Overall, the balance of evidence favored the conclusion that the midcontinent population has continued to grow during the conservation order, although perhaps at a reduced rate. We suggest that annual rate of population growth , derived from estimates of annual population size in August, likely provides the most reliable inference about change in the midcontinent population. There was a decline in annual survival probability between these 2 periods from about 0.89 to about 0.83 among snow geese from the southern‐nesting stratum (south of 60°N latitude), thought to compose about 10% of the midcontinent population. However, we detected no change in the much larger northern‐nesting stratum (north of 60°N latitude), where annual survival remained at about 0.87 from 1989 to 2006. Thus, the conclusion that this population continued to increase during the conservation order was largely consistent with the finding that a weighted‐survival probability for midcontinent snow geese essentially did not change between the period preceding (1989–1997) and during (1998–2006) the conservation order. Consistent with high survival rates were low harvest rates, which increased from 0.024 during 1989–1997 for northern geese to only 0.027 during 1998–2006 and from 0.031 to only 0.037 for southern geese. Despite the initial increase associated with the conservation order, harvest rates declined during the conservation order for geese from both strata. We suggest that the higher harvest rate evident for southern geese was related to their earlier fall migration and thus earlier exposure to harvest pressure. Migration by more abundant northern geese was later and resulted in a higher ratio of geese to hunters. Additionally, there was more harvest of southern geese in areas north of the Canadian prairies than there was of northern geese. Total annual harvest increased due to the conservation order but failed to exceed 0.75 million adults in any year during the assessment from 1989 to 2006. Harvest of both age classes exceeded 1 million in only 2 of 9 annual harvest periods since the conservation order started. These lower‐than‐expected harvests of adult snow geese combined with their low harvest rates of ≤0.048 during the conservation order suggested an August population size in excess of 15 million adult snow geese since 1998. We suggest that abundance of midcontinent snow geese was seriously underestimated in the past, and that this underestimate may have contributed to an overconfidence with which suggested harvest levels could achieve a goal of reduced survival and population reduction. Overall, all 3 populations of light geese now exceed numbers present when the conservation order was initiated. We are confident that the abundance and population growth rate of midcontinent snow geese (as well as by Ross's and greater snow geese) currently exceeds the ability of existing numbers of hunters to exert harvest pressure that is necessary to impose sufficient additive mortality and thus effectively influence population growth. It remains unknown how much more or how much longer such populations can increase towards carrying capacity, which we assume to be determined by the standing crop of arctic foods that they exploit, before density dependence can measurably slow the population growth rate. Estimation of carrying capacity in the large northern nesting stratum is among the key research needs that we propose. The situation that has emerged requires a review of perspectives about impacts of midcontinent lesser snow geese in the arctic, whether initial goals behind population management are still relevant, and whether alternative options from the initial array of management tools should be exercised. © The Wildlife Society, 2011

中文翻译：

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与减少人口活动有关的中洲小雪雁的收获，生存和丰度

我们评估了针对范围广泛的迁徙鹅的广泛而空前的减少野生动植物工作的有效性。针对人口减少的努力，针对的是几种轻鹅（大雪雁[ Chen caerulescens atlantica ]，小雪雁[ C. c。caerulescens ]和罗斯大雁[ C. rossii]）于1999年在北美中部和东部开始。之所以做出这样的努力，是因为广泛的共识，即大量的鹅正在对哈德逊湾沿岸的加拿大北极圈和亚北极地区的中部和东部地区的陆地和盐沼生态系统造成严重的生态破坏。从1999年2月开始，在各自的联邦法规中增加了特殊的保护措施（或在美国，一项保护令），允许猎人猎取雪雁（在加拿大和美国的部分地区）和罗斯雁（在加拿大的部分地区）美国）在狩猎季节以外的特定收获期。这些措施伴随着每日杀伤和拥有限制的增加或取消，以及允许使用以前被禁止的设备在该大陆某些地区狩猎这些物种的许可。目的是通过增加狩猎死亡率来降低成年生存率，这被认为是逆转人口增长的最具成本效益的方法。我们的主要目标是评估针对较小雪雁的中大陆种群的减灾工作的有效性，认为这是对3种轻鹅种群对北极和北极的生态系统的最严重威胁。我们的多个目标包括以1998年的狩猎期（定义为1998年8月1日至1999年7月31日）为参考，估计和检测总年收成，收获率，存活率和丰度响应措施的变化。我们使用了有关带状雪雁猎人回收的信息和常规季节收成的估算，以估算1）保护订单收成和年度总收成，1930）方法。我们还对人口增长进行建模，以推断出人口对管理工作做出反应的形式。为此，我们还提出了一种估计保护秩序收成的方法，并测试了加拿大和美国之间乐队报告率的差异。总体而言，证据的平衡支持这样一个结论，即中洲大陆人口在保护秩序期间继续增长，尽管增长率可能有所降低。我们建议人口的年增长率是根据8月份的年度人口规模估算得出的，它可能提供有关中大陆人口变化的最可靠推断。在这两个时期之间，来自南部嵌套地层（南纬60°）的雪雁的年生存概率从约0.89下降到约0.83，这被认为约占中部大陆人口的10％。但是，我们没有发现更大的北部嵌套地层（北纬60°N），在1989年至2006年期间的年生存率保持在0.87左右。该种群在保护秩序中继续增加的结论与以下发现基本一致：中保护雪雁的加权生存概率在保护之前（1989-1997）至（1998-2006）期间基本没有变化。订购。与高存活率一致的是低收成率，北部鹅的收成率从1989-1997年的0.024增加到1998-2006年的只有0.027，南部鹅从0.031增加到只有0.037。尽管与养护顺序相关的最初增加，但是在养护顺序中来自两个地层的鹅的收获率都下降了。我们建议南部鹅的较高收获率与它们较早的秋季迁徙有关，因此与较早的收获压力有关。后来，北方鹅的迁徙更加丰富，导致鹅与猎人的比例更高。此外，在加拿大大草原以北的地区，南部鹅的收获要比北部鹅的收获多。年度总收获量因保护令而增加，但在1989年至2006年的评估中，任何年份的成年成年人均不超过75万。自保护令开始以来，两个年龄段的收获量在9个年度收获期中只有2个超过100万。这些成年雪雁的收成低于预期，加上在保护令期间的收成率低至≤0.048，表明自1998年以来，八月成年雪雁的人口规模超过1500万。我们认为，中大陆雪雁的数量严重不足过去被低估了 并且这种低估可能导致了过度自信，建议的收获水平可能会达到减少生存和减少种群的目标。总体而言，保护令启动时，所有3种轻鹅种群现在都超过了数量。我们有信心，中大陆雪雁（以及罗斯氏和更大的雪雁）的丰度和种群增长率目前超过了现有数量的猎人施加收获压力的能力，这是施加足够的附加死亡率所必需的，从而有效地影响了人口增长。目前尚不知道这些人口可以增加多少容量或更长的时间来承载能力，我们认为这取决于它们所利用的北极食品的现成作物，密度依赖可以显着降低人口增长率之前。北部大嵌套地层的承载力估算是我们提出的关键研究需求之一。出现的情况需要审查以下观点：北极中小洲雪雁对北极的影响；人口管理背后的最初目标是否仍然有意义；以及是否应采用最初的一系列管理工具。©野生动物协会，2011年 人口管理背后的最初目标是否仍然有意义，以及是否应行使最初一系列管理工具中的备选方案。©野生动物协会，2011年 人口管理背后的最初目标是否仍然有意义，以及是否应行使最初一系列管理工具中的备选方案。©野生动物协会，2011年