Abstract：
Populations of rare and endangered species are nowadays in peril due to large-scale habitat conversion, and even sizeable and stable populations are confronted with unexpected challenges. We conducted a full census of a proboscis monkey (Nasalis larvatus) population in Balikpapan Bay and located 292 one-male-multifemale units and 67 all-male units in 2022. Using data on average group size, subsampled from Balikpapan Bay, we estimated a total population size of 3907 individuals. The rate of proboscis monkey habitat loss in Balikpapan Bay has been slowing down to the current 0.69% per year. It is predicted that habitat recovery may exceed habitat loss after 13 years. The Indonesian capital city relocation was announced in 2019 with spatial plans designed to cover a total land area of 2,560 km2 across various habitats until 2045. A total number of 1449 individuals (37.08% of the population) were found on 80.55 km2 (41.29%) of habitat that overlapped with current spatial plans of Nusantara Capital city. The construction work just started; before that, the government had already claimed it would be a \"smart, green, beautiful, and sustainable city\". We, therefore, include our recommendations to mitigate the impact of the construction and to pursue the goal to construct the most sustainable capital city, concerning local biodiversity and thus become a pioneer in a new direction of proboscis monkey conservation.
摘要：
由于大规模的栖息地转换，稀有和濒危物种的种群如今处于危险之中，甚至相当大和稳定的人口也面临着意想不到的挑战。我们对Balikpapan湾的长鼻猴（Nasalislarvatus）种群进行了全面普查，并在2022年定位了292个单雄多雌单位和67个全雄性单位。使用平均组大小的数据，从Balikpapan湾取样，我们估计总人口为3907人。Balikpapan湾的长鼻猴栖息地丧失率已放缓至目前的每年0.69％。据预测，13年后，栖息地恢复可能会超过栖息地丧失。印度尼西亚首都城市搬迁于2019年宣布，其空间计划旨在覆盖各种栖息地的总土地面积2,560平方公里，直到2045年。在80.55km2（41.29％）的栖息地中发现了1449个个体（占人口的37.08％），与努桑塔拉首都城市的当前空间规划重叠。建设工作刚刚开始；在此之前，政府已经声称这将是一个“聪明的，绿色,美丽,和可持续城市\“。我们,因此,包括我们的建议，以减轻建设的影响，并追求建设最可持续的首都的目标，关注当地的生物多样性，从而成为长鼻猴保护新方向的先驱。
