Context: Understanding what constitutes high-quality habitat for threatened species is critical for conservation management planning. The endangered northern quoll (Dasyurus hallucatus) has experienced an uneven range contraction among habitat types. Once common across multiple habitats of northern mainland Australia, declining populations have now contracted to rocky escarpments.

Aim: The island refuge of Groote Eylandt, Northern Territory, Australia, has not experienced the declines as seen on mainland Australia. Here, northern quolls persist in both rocky escarpment and savanna woodland, which provides a rare opportunity to investigate the habitat quality of rocky escarpments and savanna woodland for the northern quoll.

Methods: Northern quolls (n = 111) were trapped in both rocky escarpment (n = 61) and savanna woodland (n = 50) habitats before the breeding season (May). We conducted body condition assessment, scat analysis, and measured trophic niche breadth of individuals occupying each habitat type.

Key results: Female quolls occupying rocky escarpments exhibited a lower body condition than did quolls occupying savanna woodland. Quolls from rocky escarpments consumed a significantly higher proportion of mammals and fed within a narrower dietary niche than did those occupying savanna woodland.

Conclusions: Quolls had adapted to the dietary resources available within each habitat type, suggesting that the lack of quolls in savanna woodland on the mainland is due to factors other than availability of dietary resources.

Implications: Groote Eylandt is of critical conservation significance, where high numbers of northern quolls exist in both rocky escarpment and savanna woodland habitats. For population viability on the mainland, managing threats such as feral predators and inappropriate fire regimes in savanna woodland, particularly those surrounding rocky escarpment, should be prioritised.

背景：了解什么构成受威胁物种的高质量栖息地对于保护管理规划至关重要。濒临灭绝的北洋蓟（Dasyurus hallucatus）在生境类型之间经历了不均匀的范围收缩。曾经在澳大利亚北部大陆的多个生境中普遍存在的种群数量下降，现在已经缩为岩石峭壁。

目的：澳大利亚北领地Groote Eylandt的避难所并没有经历澳大利亚大陆那样的衰退。在这里，北部陡坡在岩质悬崖和热带稀树草原林地中都持续存在，这为调查北部陡峭岩质悬崖和热带稀树草原林地的生境质量提供了难得的机会。

方法：北quolls（ñ  = 111）被困在两个石崖（ñ  = 61）和稀树草原林地（ñ  = 50）的繁殖季节（5月）之前的栖息地。我们进行了身体状况评估，粪便分析，并测量了每种栖息地类型的个体的营养小生境宽度。

关键结果：居住在岩质悬崖上的雌性quo鼠的身体状况比居住在稀树草原林地上的quo鼠的身体状况低。与那些居住在热带稀树草原上的哺乳动物相比，来自岩壁悬崖的鹌鹑消耗了更多比例的哺乳动物，并且在狭窄的饮食生态位中觅食。

结论：鼠尾草已经适应了每种生境类型中可用的饮食资源，这表明大陆稀树草原林地中缺少类风鼠是由于饮食资源的可获得性之外的其他因素造成的。

启示： Groote Eylandt具有至关重要的保护意义，在该地区岩石陡峭的草原和热带稀树草原的生境中都存在着大量的北部沼泽。为了在大陆上维持生存能力，应优先处理野生捕食者和稀树草原林地中不适当的火势之类的威胁，尤其是岩壁悬崖周围的威胁。