Understanding environmental factors influencing the abundance of species is important for developing strategies to manage wildlife effectively. Long‐term studies provide the most reliable information upon which to base management decisions. This is particularly important when considering threatening processes, like drought and climate change, and a species' future security. We collected data on abundance of southern hairy‐nosed wombats (Lasiorhinus latifrons) on Kooloola Station in South Australia's Murraylands during nightly spot‐lighting excursions in winter and spring between 1993 and 2014. Wombat numbers declined significantly after the early‐mid 1990s, and were lowest in 2002–2003 in the middle of the millennium drought (late 1996–mid‐2010). Despite an observed decline in grazing competition from domestic sheep and rabbits (Oryctolagus cunniculus) after 2003 and above‐average rainfall in 5 of the next 11 years, the wombat population failed to recover to early–mid‐1990s levels, remaining at approximately 50% of estimated abundance pre‐drought. The study provides evidence that rainfall has a significant effect on southern hairy‐nosed wombat population size, most likely through improvements in the availability of palatable plant species. Historical information suggests that there was a change in the grass and herbaceous layer on Kooloola Station in the mid‐1970s from a pasture dominated by summer‐germinating native grass and forb species, the natural diet of the southern hairy‐nosed wombat, to one dominated by winter‐germinating introduced weeds. Several consecutive years of above‐average rainfall are needed before effective wombat population increase occurs and the size of yearly winter and spring rainfall events is strongly linked to population trends the following year. Historical information and first‐hand observations suggest that dietary components (either native grasses or introduced weed species) and level of grazing competition may also interact to affect wombat survival and population recovery from drought, although this requires further testing. Together with rainfall, these factors have important implications to develop appropriate conservation and management strategies for this species in a changing climate likely to be dominated by increased drought frequency and duration. © 2020 The Wildlife Society.

中文翻译：

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在半干旱牧场中影响毛鼻袋熊丰度的环境因素

了解影响物种丰富度的环境因素对于制定有效管理野生动植物的策略很重要。长期研究提供了最可靠的信息，可作为管理决策的依据。当考虑到诸如干旱和气候变化等威胁过程以及物种的未来安全性时，这一点尤其重要。我们收集了有关南方毛鼻袋熊（Lasiorhinus latifrons），在1993年至2014年冬季和春季的冬季和春季，夜间在南澳大利亚州的穆雷兰岛的Kooloola站上。袋熊的数量在1990年代初期中期之后显着下降，在2002-2003年间处于千年干旱中期（最低1996年– 2010年中）。尽管观察到家养绵羊和兔子的放牧竞争有所下降（Oryctolagus cunniculus）在2003年以后以及接下来的11年中有5年高于平均水平的降雨量下，袋熊种群未能恢复到1990年代中期的水平，仍然保持在估计干旱前的丰度的50％左右。这项研究提供了证据表明降雨对南部多头袋熊的种群数量有重大影响，这很可能是通过改善可口植物物种的可获得性来实现的。历史信息表明，1970年代中期，库洛奥拉站的草层和草本层发生了变化，从以夏季发芽的本机草和福布斯树种（南部毛鼻袋熊的自然饮食）为主的牧场变为一种以草食为主的草场。通过冬季发芽引入的杂草。有效的袋熊种群数量增加之前，需要连续几年达到高于平均水平的降雨量，而每年冬季和春季降雨事件的规模与第二年的人口趋势密切相关。历史信息和第一手观察表明，饮食成分（天然草或引入的杂草物种）和放牧竞争水平也可能相互作用，影响袋熊的生存和干旱恢复种群，尽管这需要进一步测试。这些因素与降雨一起，对于在气候变化中可能以干旱频率和持续时间增加为主导的该物种制定适当的保护和管理策略具有重要意义。©2020野生动物协会。