Spatial Association and Diversity of Dominant Tree Species in Tropical Rainforest, Vietnam

Abstract

Explaining the high diversity of tree species in tropical forests remains a persistent challenge in ecology. The analysis of spatial patterns of different species and their spatial diversity captures the spatial variation of species behaviors from a ‘plant’s eye view’ of a forest community. To measure scale-dependent species-species interactions and species diversity at neighborhood scales, we applied uni- and bivariate pair correlation functions and individual species area relationships (ISARs) to two fully mapped 2-ha plots of tropical evergreen forests in north-central Vietnam. The results showed that (1) positive conspecific interactions dominated at scales smaller than 30 m in both plots, while weak negative interactions were only observed in P2 at scales larger than 30 m; (2) low numbers of non-neutral interactions between tree species were observed in both study plots. The effect of scale separation by habitat variability on heterospecific association was observed at scales up to 30 m; (3) the dominance of diversity accumulators, the species with more diversity in local neighborhoods than expected by the null model, occurred at small scales, while diversity repellers, the species with less diversity in local neighborhoods, were more frequent on larger scales. Overall, the significant heterospecific interactions revealed by our study were common in highly diverse tropical forests. Conspecific distribution patterns were mainly regulated by topographic variation at local neighborhood scales within 30 m. Moreover, ISARs were also affected by habitat segregation and species diversity patterns occurring at small neighborhood scales. Mixed effects of limited dispersal, functional equivalence, and habitat variability could drive spatial patterns of tree species in this study. For further studies, the effects of topographical variables on tree species associations and their spatial autocorrelations with forest stand properties should be considered for a comprehensive assessment.

Topographic Effects on the Spatial Species Associations in Diverse Heterogeneous Tropical Evergreen Forests

“…They suggested that independence may be the dominant association type in communities with high biodiversity. Our findings are in line with those mentioned above as well as other studies (e.g., Nguyen et al [26], Zhou et al [48]) using the approach of classification scheme for association patterns of tree species.…”

“…The study plots of 100 × 200 m (Figure 2), P1 (17 • 20 11" N, 106 • 26 30" E) and P2 (17 • 20 15" N, 106 • 26 24" E) recorded by Garmin 60 s GPS (Global Positioning System) using WGS-84 datum at the center of the plots, were designed and subdivided into two grid systems of 200 (10 × 10 m) subplots for measuring tree individuals and topographic data. Slope of the plots ranges from 5 to 45 degrees with an elevation ranging from 119 to 184 m above sea level [26]. Tree individuals with dbh (diameter at breast height) ≥ 2.5 cm were stem-mapped within the plots and their biophysical characteristics (i.e., species type and dbh) were recorded.…”

The ecological interaction between endangered, precious and rare woody species in rich forest community: A case study in Tanphu protection forest, Vietnam

“…This result is different from the study results of Souza et al (2014) and Ruan et al (2021Ruan et al ( , 2022 when analyzing ecological clustering in tropical evergreen broadleaved forest types. Compared with some previous studies in Vietnam, our study also indicated the degree of grouping between tree species (Nguyen et al 2016(Nguyen et al , 2018. The current study's findings are very meaningful in the selection and combination of tree species in mixed afforestation.…”

Spatial point-pattern analysis as a powerful tool in identifying pattern-process relationships in plant ecology: an updated review

“…dead vs living). For all analysis types, positive, negative, or absence of departure from the null model simulation envelopes occurs at a given scale r (Continued) Iszkuło et al 2012;Zhang et al 2013;Navarro-Cerrillo et al 2013;Ebert et al 2015;Wehenkel et al 2015;Jácome-Flores et al 2016;Jia et al 2016;Zhang et al 2016;Owen et al 2017;Gradel et al 2017;Zheng et al 2017;Nguyen et al 2018b;Omelko et al 2018;Muvengwi et al 2018;Vandekerkhove et al 2018;Kazempour Larsary et al 2018;Lv et al 2019;Baran et al 2020 Patterns 1 and 2 are segregated Riginos et al 2005;Hao et al 2007;De Luis et al 2008;Batllori et al 2010;Navarro-Cerrillo et al 2013, Kang et al 2014Cordero et al 2016;Hu et al 2017;Miao et al 2018;Bassil et al 2018; Wang et al 2010a;Zhang et al 2010;Martínez et al 2010;Lan et al 2012;Liu et al 2014;Petritan et al 2014Petritan et al , 2015Wang et al 2015;…”