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Abstrak :
The conservation of the endemic tree species Dipterocarpus littoralis (Bl.) Kurz. is hampered by the paucity of information on its population biology and ecology. Consequently, a targeted survey was carried out in the West Nusakambangan Nature Reserve to assess its population size and structure as well as habitat preferences. In total, 676 individuals of D. littoralis were located at 52 locations, with an extent of occurrence of 3.66 km2 and an area of occupancy of 1.71 km2. The population had an inverse-J-shaped distribution of diameter at breast height (DBH), with 63% of individuals in the 0-5 cm class and another 21% in the 5-10 cm class; only 11 (1.6%) mature individuals (DBH≥30) were found. D. littoralis was associated with steep, low, southwest-facing sites and sites that had high litter cover and thickness. Illegal logging and fuel-wood chopping were the main threats to D. littoralis and its habitat. In addition, an invasive shrub, Langkap (Arenga obtusifolia, Arecaceae), was a potential competitor with the seedlings throughout the reserve. In view of its endemism, narrow range and localized distribution, small population, environmental preferences, and the severe threats from anthropogenic activities and invasive species, D. littoralis appears to more than justify its conservation status of Critically Endangered.

Status Populasi dan Preferensi Habitat Jenis Kritis Dipterocarpus Littoralis di Nusakambangan Barat, Indonesia. Usaha konservasi jenis endemik Dipterocarpus littoralis (Bl.) Kurz. terhambat karena kurangnya informasi mengenai biologi dan ekologi populasi tumbuhan ini. Oleh karena itu pada penelitian ini dilakukan survey terarah di Cagar Alam Nusakambangan Barat untuk mengetahui struktur dan ukuran populasi serta preferensi habitat dari D. littoralis. Total sebanyak 676 individu D. littoralis di temukan di 52 lokasi dengan tingkat keberadaan (extent of occurrence) 3,66 km2 dan luas area yang ditempati (area of occupancy) 1,71 km2. Populasi D. littoralis memiliki sebaran diameter batang setinggi dada (DBH) berbentuk huruf J terbalik dengan persentase individu dalam kelas DBH 0-5 cm sebesar 63%, kelas 5-10 cm sebesar 21% dan individu dewasa (DBH ≥30) hanya sebesar 1,6%. Keberadaan D. littoralis berasosiasi dengan lokasi yang terjal, rendah, menghadap ke tenggara dan memiliki tutupan serta ketebalan serasah yang tinggi. Penebangan dan pengambilan kayu bakar secara liar merupakan ancaman utama terhadap keberadaan D. littoralis dan habitatnya. Selain itu, tumbuhan invasif Langkap (Arenga obtusifolia, Arecaceae) yang tersebar di seluruh cagar alam merupakan saingan utama anakan D. littoralis. Karena bersifat endemik, area sebaran yang sempit dan terlokalisasi, ukuran populasi yang kecil, preferensi terhadap habitat tertentu, dan ancaman yang serius dari aktifitas manusia dan jenis invasif, maka D. littoralis memiliki dasar yang kuat untuk tetap dalam status konservasi Kritis (Critically Endangered).

Abstrak :
The Critically Endangered Cacatua sulphurea abbotti is a unique subspecies of cockatoo, endemic to a single tiny Masakambing Island in Indonesia. Data procurement on the status and distribution of their wild population is necessarily urgent in order to determine the best conservation strategy for this species. Data were collected annually from 2008-2018 by a direct roost count method in a roosting tree. Only 10 cockatoos were recorded in 2008, but the number continually increased up to 22 birds in 2018 (42.86% increase in a decade). The population was distributed in about 71% of the total size of the island, concentrated in the north-western part with a density of 1.56 (~ 2 birds/km2) in 2008 which raised up to 3.44 (~ 3 birds/km2) in 2018. The zero trapping policy enforced by the local government was probably effective in preventing the population decline, although the population is still vulnerable due to nesting failure, presumably low genetic quality and habitat destruction.