Abstract “Conservation-reliant species” – those fully dependent on continued management actions – are booming and, with limited conservation budgets, securing funds to sustain their long-term viability is becoming overwhelming. This study assesses the degree of dependence on conservation actions of two obligatory cavity-nesters, the Lesser Kestrel Falco naumanni and the European Roller Coracias garrulus, whose populations in Europe were recently recovered through artificial nest-site provisioning. Using long-term monitoring data and population surveys conducted in their main Portuguese stronghold, we examined temporal changes in the availability and use of semi-natural (cavities in rural abandoned buildings) and artificial nest-sites. We further assessed the financial costs of nest-site provisioning and evaluated the potential use of tourism revenues as a conservation funding source. Following the implementation of conservation projects, the Lesser Kestrel and Roller populations have been increasing but >65% of all breeding pairs currently nest in artificial nest-sites. Semi-natural nest-sites remain suitable for approximately 30 years and are expected to disappear by the end of this century. Lesser Kestrels and Rollers will thus become fully dependent on artificial nest-sites and sustaining their current population sizes is estimated to cost 4500€ per year. This represents

中文翻译：

---

依赖保护的物种的长期存在：挑战和机遇

摘要 “依赖保护的物种”——那些完全依赖持续管理行动的物种——正在蓬勃发展，而且由于保护预算有限，获得资金来维持其长期生存能力变得势不可挡。这项研究评估了两个强制性窝巢鸟对保护行动的依赖程度，即小红隼和欧洲罗勒科拉西亚斯 garrulus，它们在欧洲的种群最近通过人工巢址供应恢复。使用长期监测数据和在葡萄牙主要据点进行的人口调查，我们研究了半自然（农村废弃建筑中的空洞）和人工巢穴的可用性和使用的时间变化。我们进一步评估了巢址供应的财务成本，并评估了旅游收入作为保护资金来源的潜在用途。随着保护项目的实施，小红隼和罗勒的数量一直在增加，但目前所有繁殖对中有 65% 以上在人工巢穴中筑巢。半天然的巢穴可以保留大约 30 年，预计到本世纪末会消失。因此，小红隼和罗勒将完全依赖人工巢穴，维持它们目前的种群规模估计每年需要花费 4500 欧元。这代表 目前，所有繁殖对中有 65% 在人工巢穴中筑巢。半天然的巢穴可以保留大约 30 年，预计到本世纪末会消失。因此，小红隼和罗勒将完全依赖人工巢穴，维持它们目前的种群规模估计每年需要花费 4500 欧元。这代表 目前，所有繁殖对中有 65% 在人工巢穴中筑巢。半天然的巢穴可以保留大约 30 年，预计到本世纪末会消失。因此，小红隼和罗勒将完全依赖人工巢穴，维持它们目前的种群规模估计每年需要花费 4500 欧元。这代表