Review: Diversity, structure, and community composition of Bornean heath forest with a focus on Brunei Darussalam

Abstract

Abstract. Ikbal IM, Din HHM, Tuah WH, Jaafar SM, Ahmad N, Sukri RS. 2023. Review: Diversity, structure, and community composition of Bornean heath forest with a focus on Brunei Darussalam. Biodiversitas 24: 2814-2829. Tropical heath forests, a unique lowland forest ecosystem with high conservation value, are increasingly threatened by disturbances. Heath forests are characterized by trees of short stature and the presence of highly acidic, sandy soils with poor nutrient content. Bornean heath forests are widely studied for their diversity, structure, and community composition and are known to support endemics of high conservation value. Environmental factors and soil properties, such as topography, water availability, and nutrient status, are known to influence tree species diversity and forest structure of Bornean forests. However, factors influencing their community composition, including the role of seedling communities in influencing heath forest communities, are still not well understood. In particular, studies of tree diversity and community composition of heath forests in Brunei Darussalam have revealed high endemism and the presence of species with high conservation value. Anthropogenic threats to Bornean heath forests highlight the urgent need for an increased understanding of these forests and prioritization of their conservation. Increased insights into the ecological preferences of heath forest species are crucial for the successful restoration of degraded heath forests. The intact forest ecosystems of Brunei could provide opportunities for further ecological research on the plant communities found in these unique forests.

Ecophysiological responses of native and introduced coastal tree species parasitized by Cassytha filiformis in Brunei

“…In Brunei Darussalam, C. filiformis is commonly found along the coastal highways where secondary heath ( Kerangas ) forests are located (Rosli, 2014 ; Tennakoon et al., 2016 ). In general, heath forests are characterized by their acidic, nutrient‐poor sandy soils and are home to Kerangas specialists, such as tropical conifers Agathis borneensis , Gymnostoma nobile , and Calophyllum ferrugineum (Ikbal et al., 2023 ; Sellan et al., 2022 ; Wong et al., 2015 ; Zoletto & Cicuzza, 2022 ). However, when disturbed, these forests are often dominated by native pioneer species, such as Rhodomyrtus tomentosa , Timonius flavescens , and Commersonia bartramia , and the exotic and highly invasive Acacia species, which pose a significant threat to the forest ecosystems (Din et al., 2015 ; Newbery, 1991 ; Tuah et al., 2020 ).…”

Floristic diversity and composition of heath forest in Kuala Tambangan Village, Tanah Laut District, Indonesia

“…In Indonesian Borneo (Kalimantan), heath forests occur in the provinces of West Kalimantan (Navratil 2013;Utari et al 2023), Central Kalimantan (Maimunah et al 2019;Kissinger 2022), East Kalimantan (Kartawinata 1980;Navratil 2013;Setiawan et al 2021), North Kalimantan (Agustiorini et al 2022) and South Kalimantan (Nugroho et al 2022b). Heath forests also occur in Brunei Darussalam (Din et al 2015;Ikbal et al 2023;Zaini and Sukri 2014) and Malaysian Borneo (Sabah and Sarawak) (Lim 2006). Besides occurring on the two islands, heath forests can be found in Peninsular Malaysia, such as in Terengganu (Syuharni et al 2014) and Pahang (Chua et al 1995), although according to (Kamoona et al 2023) in Pahang there is a high risk of disappearing or even in some locations it has not seen anymore.…”