Accepted Manuscript Diversity depends on scale in the forests of the Central Highlands of Vietnam Ha Thi Thanh Do, John C. Grant, Bon Ngoc Trinh, Heidi C. Zimmer, J. Doland Nichols PII: S2287-884X(17)30100-0 DOI: 10.1016/j.japb.2017.08.008 Reference: JAPB 252 To appear in: Journal of Asia-Pacific Biodiversity Received Date: 17 November 2016 Revised Date: 18 August 2017 Accepted Date: 24 August 2017 Please cite this article as: Thanh Do HT, Grant JC, Trinh BN, Zimmer HC, Nichols JD, Diversity depends on scale in the forests of the Central Highlands of Vietnam, Journal of Asia-Pacific Biodiversity (2017), doi: 10.1016/j.japb.2017.08.008. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT 1 Diversity depends on scale in the forests of the Central 2 Highlands of Vietnam 3 4 Ha Thi Thanh Do a*,b , John C. Grant a, Bon Ngoc Trinh b, Heidi C. Zimmer a, J. Doland Nichols a 5 6 a Forest Research Centre, Southern Cross University, Lismore NSW Australia 2480. * Corresponding author 7 [email protected] 8 b Silviculture Research Institute, Vietnam Academy of Forest Science, Bac Tu Liem, Ha Noi, Vietnam 9 MANUSCRIPT ACCEPTED ACCEPTED MANUSCRIPT 10 Abstract: Tropical forests are among the most diverse ecosystems on earth. They are also 11 the most threatened. The montane forests in the Central Highlands Region of Vietnam have 12 outstanding biodiversity and suite of unique species, yet we know little about them. This 13 study focuses on characterising natural forest at three sites: Dam Rong, Ha Nung and Yok 14 Don. We identified six discrete communities and their indicator species. One community, 15 Highland Floodplain forest, had tree species richness of up to 22 species/400 m 2 and 70 16 species/ha. In the lowland forests of Yok Don we identified three distinct communities, 17 despite that area having the lowest mean species richness (5 species/400 m 2). This study 18 illustrates the high species richness of the forests of Vietnam, and provides an important 19 record of the tree species (including rare and threatened species) at each of these sites. Our 20 community determinations can be used in future conservation management planning. 21 Moreover, the presence of three distinct tree commuMANUSCRIPTnities at Yok Don, which had the 22 lowest species richness, highlights that biodiversi ty should be assessed at multiple scales. 23 24 Keywords : Annamite mountains, Dam Rong, dipterocarp forest, Ha Nung, montane 25 rainforest, Yok Don 26 ACCEPTED ACCEPTED MANUSCRIPT 27 Introduction 28 29 The diversity of life on earth maintains the ecosystem services on which humans rely 30 (Chapin III et al 2000). Yet recent species losses implicate human actions as the cause of a 31 sixth mass extinction (Chapin III et al 2000). Resources for biodiversity conservation are 32 limited, and it is for this reason we must prioritise which areas are most critical for 33 protection (Mittermeier et al 1998). ‘Biodiversity hotspots’ provide one such prioritisation 34 strategy. Across the world, twenty-five regions have been named biodiversity hotspots. 35 Many of these high biodiversity areas with high levels of animal and plant endemism, are 36 threatened (Myers et al 2000). Tropical forests encapsulate more than half of the world’s 37 plant species and appear in 15 of the 25 biodiversity hotspots. They are also being depleted 38 faster than any other ecosystem (Myers 1988). MANUSCRIPT 39 Primary tropical forests, because of their high spe cies richness, constitute some of the most 40 complex ecosystems on earth (Gibson et al 2011; Wilson et al 2012) and are known for 41 being difficult to sample effectively and efficiently (Phillips et al 2003). Nevertheless, 42 distinct classification of tropical forests, as with all vegetation types, is fundamental to the 43 management, mapping and study of these systems (Biondi and Zuccarello 2004; De 44 Cáceres et al 2015). Classification of the world’s vegetation communities (and development 45 of classification methodology) has been underway for over a century (Mucina 1997). The 46 conceptualisationACCEPTED of discrete communities has been a large challenge (Looijen & van Andel 47 1999; Wilson & Chiarucci 2000), but there continues to be a focus on producing well- ACCEPTED MANUSCRIPT 48 functioning local vegetation classifications (cf. ill-fitting broad ones) that are fit for purpose 49 (e.g. conservation management) (Mucina 1997). 50 Historically, Thái (1963; 1999) classified Vietnam’s vegetation into five types and 14 51 subtypes. The first order classification was based on geography (highland or lowland), 52 canopy structure (closed or open), and climate. Vegetation communities were then 53 identified by edaphics, the level of disturbance and floristics, and finally identified by the 54 dominant species (or genera or families) (Thái 1963; 1999). The biodiversity of Southeast 55 Asia, which includes four biodiversity hotspots, has been under assault in recent decades 56 (Sodhi et al 2004). The region has the highest relative rate of deforestation of all major 57 tropical regions. Sodhi et al (2004) emphasised that the extent of this disaster may be far 58 greater than is currently understood, because of the paucity of research data. In addition, 59 biodiversity conservation research in the tropics MANUSCRIPTis chronically underfunded (Balmford and 60 Whitten 2003; Gardner et al 2008; Vieilledent et al 2016). The Indo-Burma biodiversity 61 hotspot (Myers et al 2000), is one of the four South-east Asian hotspots, and it includes all 62 of Vietnam. Most of this biodiversity occurs in Vietnam’s mountains, located in the north- 63 west, north-east and central regions, while the majority of flatlands have been cleared for 64 cultivation and urbanisation (Meyfroidt and Lambin 2008). 65 The Central Highlands region (CHR) in central Vietnam encapsulates most of the 66 remaining forests with high biodiversity value in Vietnam (Meyfroidt and Lambin 2008). 67 The CHR spansACCEPTED five provinces and is topographically dominated by the Annamite 68 Mountains (Day Truong Son). The montane rainforests of the northern and southern 69 Annamite Mountains have been highlighted by the WWF as ‘global ecoregions’ (Olson et ACCEPTED MANUSCRIPT 70 al 2001). The WWF designation indicates that these areas contain geographically unique 71 species, communities and conditions, with globally outstanding biodiversity (Olson et al 72 2001). Most famously, Annamite montane rainforests include regionally significant conifer 73 species richness, and the recently discovered large mammals, saola and giant muntjac 74 (Wikramanayake et al n.d.). In an analysis of biodiversity of ecoregions in the Indo-Pacific, 75 based on combined species richness and endemism, Krupnick and Kress (2003) found that 76 within the Indo-Burma biodiversity hotspot, the Southern Annamites montane rainforest 77 had the highest biodiversity. Biodiversity in the CHR is subject to pressures typical 78 throughout Vietnam, including deforestation as a result of immigration and the 79 development of market crops (Meyfroidt et al 2013), and dams, including Yali Falls dam – 80 the largest dam in the lower Mekong Basin (Polimeni et al 2014). Approximately half 81 (2,864,100 ha) of the CHR is forest, while approximMANUSCRIPTately one third (1,952,800 ha) is 82 devoted to agriculture of paddy rice, coffee, sugarcane and other commercial crops 83 (General Statistical Office of Vietnam 2013). 84 There are few studies of Vietnamese forests that have been published in the international 85 literature. Tran et al (2013) detailed the relationship between biodiversity and biomass of 86 major natural forest types in Vietnam. Blanc et al (2000) described communities and 87 succession of forests in Cat Tien National Park, Dong Nai Province. There are also two 88 studies that report on the spatial distributions (typically aggregated) of trees in the forests of 89 northern VietnamACCEPTED (Hai et al 2014; Nguyen et al 2016) and several studies that focus on the 90 influences of humans on threatened tree species (Dao and Hölscher 2015) and on plant 91 composition in general (Hoang et al 2011). These studies were conducted in northern ACCEPTED MANUSCRIPT 92 Vietnam. Despite outstanding biodiversity, very little has been published in the 93 international scientific literature about the tropical forest communities of Vietnam, and less 94 on attempts to characterise vegetation communities. Studies on the globally significant 95 CHR are particularly lacking. We aim to address this research gap. 96 This study describes the forest tree communities, and their indicator species, at three sites in 97 the little-studied, biologically significant Central Highlands region of Vietnam. 98 Biodiversity indices and species accumulation curves are presented for each community. To 99 support descriptions of these communities we present soil, climate and elevation data. 100 101 Materials and methods 102 Study area MANUSCRIPT 103 The Central Highlands Region (CHR) is located in the southeast of the Indochina Peninsula, 104 between longitude 11°11’ N (Lam Dong) to 15°25’ N (Kon Tum), and across longitude 105 107°12’ E ( Đak Nong) to 109°30’E. This region is at the southern end of Annamite Range, 106 Vietnam (Appendix Fig. 1). The majority of the CHR is from 100 to 800 m, although the 107 region also encompasses high mountains, including Ngoc-Linh (2,598 m). The CHR has 108 three main topographic classes: mountains, plateau and plain/delta (Nguy ễn et al 2000).