Species Composition and Spatial Distribution of Dominant Trees in the Forest Ecotone of a Mountain Ecosystem, Northern Thailand
Total Page:16
File Type:pdf, Size:1020Kb
Environment and Natural Resources Journal 2019; 17(3): 40-49 Species Composition and Spatial Distribution of Dominant Trees in the Forest Ecotone of a Mountain Ecosystem, Northern Thailand Dokrak Marod1,2, Sutheera Hermhuk1,3*, Sarawood Sungkaew1,2, Sathid Thinkampheang4, Torlarp Kamyo5 and Wimonmart Nuipakdee6 1Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand 2Center for Advanced Studies in Tropical Natural Resources, NRU-KU, Kasetsart University, Bangkok 10900, Thailand 3Faculty of Agricultural Production, Maejo University, Chiang Mai 50290, Thailand 4Cooperation Centre of Thai Forest Ecological Research Network, Kasetsart University, Bangkok 10900, Thailand 5Department of Agroforestry, Maejo University, Phrae Campus, Phrae 54140, Thailand 6Man and Biosphere Programme, Mae Sa-Kog Ma Biosphere Reserve Office, Department of National Parks, Wildlife and Plant Conservation, Bangkok 10900, Thailand ARTICLE INFO ABSTRACT Received: 9 Oct 2018 Plants’ ecological niches are important to study, particularly for applying the Received in revised: knowledge to restoration programs. This study clarified the relationships of tree 11 Jan 2019 species composition and spatial distribution to environmental factors in a mountain Accepted: 29 Jan 2019 ecosystem. A 3 ha permanent plot was established across the forest ecotone at Doi Published online: Suthep-Pui National Park, Chiang Mai Province, Thailand. The spatial distributions 19 Mar 2019 DOI: 10.32526/ennrj.17.3.2019.21 of the 20 dominant tree species were analyzed using a generalized linear model (GLM) combined with geographic information system (GIS) techniques. High Keywords: species diversity was found, including 165 species representing 118 genera and 59 Doi Suthep-Pui National Park/ families. Elevation strongly influenced tree distribution, which could be divided into Ecological niche/ Forest three groups: low-altitude species in deciduous dipterocarp forest (DDF), high- ecotone/ Long-term ecological altitude species in lower montane forest (LMF) and coexisting DDF and LMF research /Permanent plot species. The GLM analysis revealed that soil texture, which ranged from sandy to clayey, influenced tree distribution. The results suggest that restoration programs should select suitable species based on their niches. * Corresponding author: E-mail: [email protected] 1. INTRODUCTION 2003; Valencia et al., 2004) . Such plots not only Environmental factors control plant provide information about the forest dynamics but can regeneration processes, including plant also be used to study species distribution (Dallmeier, establishment, reproduction and distribution (Guisan 1992; Condit et al., 1999). Statistical approaches such and Zimmermann, 2000; Turner, 2001). Many as canonical correspondence analysis or logistic researchers have defined two types of ecological regression are used to analyze species distribution as gradient affecting plant distributions. The first a function of environmental factors (Guisan and includes direct factors that govern physiological Zimmermann, 2000; Lan et al., 2011; Asanok et al., processes (nutrients and climatic factors) and the 2017). For instance, the dominant species is second comprises indirect factors (such as determined based on the total number of trees (Li et topographic factors, habitat type and geology) that al., 2009; Lan et al., 2011; Asanok et al., 2017; have no direct physiological relevance to species Walthert and Meier, 2017) and quantitative values performance or survival strategies (Guisan et al., such as the importance value index (Campos et al., 1999; Austin, 2002; Bacaro et al., 2008). Indirect 2000) and total basal area (Homeier et al., 2010; Höfle factors can be measured in the field and are often used et al., 2014) are used as dependent variables. The because they are correlated with the observed tree results reflect the appearance of a niche or the spatial distributions. suitability of a species in a particular area (Lan et al., Studies based on long-term ecological research 2011). A tree distribution map often needs to be have reported that large permanent plots can be used coupled with geographic information systems (GIS), to predict plant distribution (Bunyavejchewin et al., which have become popular in recent forest ecology https://doi.org/10.32526/ennrj.17.3.2019.21 Marod D et al. / Environment and Natural Resources Journal 2019; 17(3): 40-49 41 studies (Caillaud et al., 2010; Walthert and Meier, 2. METHODOLOGY 2017), particularly in tropical forests, where high 2.1 Study area plant species diversity is associated with The study area in Doi Suthep-Pui National Park environmental conditions (Condit et al., 1999; Harms is located at latitude 18° 43'3" - 19° 7'30" N and et al., 2001; Lan et al., 2011). Although studies have longitude 98° 48'20" - 98° 57'10" E in Chiang Mai covered almost all forest types, few have documented Province, Thailand (Figure 1). About 85% of the land the forest ecotone (FE) between lowland and upland cover is forest and 15% consists of agricultural land forest along altitudinal gradients. and urban areas (Charnsungnern and Tantanasarit, The mountain ecosystem in the upper reaches 2017). The area is characterized by a subtropical of the Ping River at Doi Suthep-Pui, Chiang Mai climate, with a long dry season alternating with a Province, Northern Thailand, is an important area for short, wet season; the annual precipitation is 1,139 plant conservation (Fukushima et al., 2008). The mm and mean temperature is 24°C. The altitude environmental factors responsible for plant ranges from 312 to 1,656 m.a.s.l. Geologically, the distribution can vary in the FE located between area contains steep hills and valleys consisting of lowland and upland forest (Tang and Ohsawa, 1997), high-grade metamorphic complex rocks and especially the topographic and climatic factors sandstone (Rhodes et al., 2005). The soil texture (Martin et al., 2007). In addition, soil properties in this varies along altitudinal gradients from sandy soil and area also vary due to the soil parent material, which is sandy clay loam at lower elevations to mostly sandy related to topographical and geological gradients clay loam and clay soil at higher elevations (above (Rhodes et al., 2005; Weill and Munkholm, 2015) or 1,000 m.a.s.l.) (Marod et al., 2014). Complex vegetation cover (Ueda et al., 2017). Deciduous and environmental factors are found in the Doi Suthep-Pui evergreen species coexist in the FE located at altitudes mountain ecosystem, especially elevation gradients, between deciduous dipterocarp forest (DDF) and which influence the distribution of forest types; these lower montane forest (LMF) (Marod et al., 2015). The can be classified into deciduous forest (mixed plants in this FE are very sensitive to environmental deciduous forest and deciduous dipterocarp forest), changes (Odum, 1959; Frelich, 2002; Marchand and mostly found in low elevations <1,000 m.a.s.l. and Houle, 2006), especially increases in temperature and evergreen forest (lower montane forest and pine drought (Ameztegui and Coll, 2011). Marod et al. forest), mostly found at higher elevations (≥1,000 (2015) reported that deciduous species, which mostly m.a.s.l.) (Marod et al., 2014). occupy the DDF and are highly adapted to drought, can occur at higher altitudes. By contrast, evergreen 2.2 Plot establishment and investigation species are susceptible to environmental changes. In 2016, a 3 ha permanent transect (50 × 600 Therefore, rapid environmental changes may m2) was established in the FE between DDF and LMF influence their regeneration and distribution (Ruiz et (latitude 18°47'4"N, longitude 98°54'58"E), where the al., 2008). However, little long-term ecological elevation ranged from 900 to 1,100 m.a.s.l. (Figure 1). research has examined the adaptation and migration According to Hermhuk (2014) and Marod et al. (2015), of tree species in a LMF in relation to changes in three forest zones were identified based on stand environmental variables. Consequently, this study clustering and canonical correspondence analysis clarified the species composition and examined (CCA) related to their elevation: a DDF zone from 900- correlations between spatial tree distribution and 940 m.a.s.l., a FE zone from 941-980 m.a.s.l. and a environmental factors (topographic and soil LMF zone above 980 m.a.s.l. The transect plot was properties) in a 3 ha permanent plot in Doi Suthep-Pui divided into 300 subplots (10 × 10 m2). Trees with a National Park, Northern Thailand. The results of this diameter at breast height (DBH) larger than 1 cm were research should support natural resources tagged; then, DBH was measured, positions were management, especially the selection of trees for recorded as (x, y) coordinates, and the species were restoration programs in mountain ecosystems. identified based on Smitinand (2014). 42 Marod D et al. / Environment and Natural Resources Journal 2019; 17(3): 40-49 Figure 1. The location of the study site and permanent plot in Doi Suthep-Pui National Park, Chiang Mai Province, Thailand. 2.3 Environmental data collection 2.4 Data analysis 2.3.1 Topographic factors 2.4.1 Forest structure and species composition The topographic factors (elevation, slope and The forest structure and species composition aspect) of the subplots were characterized using a are described in terms of the number of individual digital elevation model (DEM) developed by the Geo- stems, the basal area (BA) and the dominant species Informatics and