Advances in Forestry Letters, Volume 4 2015 www.afl‐journal.org doi: 10.14355/afl.2015.04.004 23 Spatial Evaluation of Plant Community Structure and Species Abundance Using TWINSPAN‐ PC ORD Egbuche Christian Toochi 1 ,Su Zhiyao 2 , Oboho E.G 3 and Nwaihu E.C 1 1 Department of Forestry and Wildlife Technology, School of Agriculture and Agricultural Technology, Federal University of Technology Owerri, Imo State Nigeria 2 College of Forest Ecology, South China Agricultural University Guangzhou, China 3 Dept of Forestry & Wildlife, Faculty of Agriculture University of Benin, Benin City, Nigeria Corresponding author Email: Egbuche C.T (ctoochi@yahoo.co.uk) Phone: +234‐8068093593 Abstract There is need to explore the relationships and assess plant community census and patterns. In 18 grid plots in Dalingshan forest was used to conduct plant community structure and abundance evaluation. Plant and vegetation community types were analyzed using TWINSPAN‐ PC ORD (Two‐way Indicator Species Analysis). A field survey was conducted and GPS based map was established. Field/grid map and TWINSPAN were employed to identify species abundance within spatial nutrient distributions. The study was designed to grid the site at 200 x 200 m spatial patterns. 18 grid plots were adopted to identify species abundance and characteristics and total of 99 species observed. TWINSPAN using the PC‐ORD software was applied to develop four groups plot dendogram. The entire field procedure was used to establish species census and abundance spreadsheet which aided census of species at medium abundance identified Rhuschinensis (Rch) of abundance (95), Adiantumcapillus (Aca) abundance (90), Blechnumorientale (Bar) abundance (87) and Agaratumconyzoides (Aco) abundance (80). Species of optimum abundance identified Hedyotisauricularia (Hau) 3767, Miscanthussinensis (Msi) 2520, Lophatherumgracile (Log) 833 and Mikaniamicrantha (Mmi) 803 respectively. In furtherance, the results showed that species of floristic composition identified at optimum abundance in percentage (%) include Hedayotisauricularia (32%), Mikaniamicrantha (21%), Hophatherumgracile (7%) and Mikaniamicrantha (7%). This study thereby suggests that the species evaluation can be utilized for further studies on multifactor ecosystem responses towards regional ecological restoration. However, it is critically required to conduct further studies on spatial patterns of soil nutrient distributions in both forest regimes and at regional level. Keywords TWINSPAN, PC –ORD, Species Abundance, Plant Community Structure, Plant Census, Spatial Patterns, DalingshanForest, Guangdong Province China Introduction Investigations on plant competition and diversity, which are substantially affected by spatial interactions, nutrient distribution and vegetation heterogeneity have been documented by Jackson and [1] and [2], [3] in forest dynamics explicitly considered under spatial and temporal scales. Such vegetation dynamics models developed include [4] that defined spatial and temporal scale variability factors. The link among plant community composition, nutrient distribution and competition for underground nutrient (resources) and differences in the temporal spatial distribution within vegetation variability has attracted extensive literature reports, such as [5], [6],[7] and [8] to mention a few. Some physiological factors of a given forest region such as topography, terrain, soil, climate and agricultural practices as well as the effect of long‐term human activity and forest plant community type protection are becoming complex factors. Some researchers had focused on variables of indicators of spatial position, soil, topography and environmental factors using TWINSPAN to analyze plant community types. Forest and environmental ecologists are finding plant community and structure pattern very important, however, it is attracting greater focus and in a broad sense that plant community distribution pattern and abundance are influenced by many environmental factors such as climate, soil and topographic features. Generally, natural plant communities are distributed continuously that composed of different plant community successions. The successions in plants community do respond to ecological and environmental factors at different times.