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Fine scale heterogeneity of soil properties causes seedling spatial niche separation in a tropical rainforest

Xia, Shang-Wen, Cao, Min, Yang, Xiaodong, Chen, Jin, Goodale, Uromi Manage
Plant and soil 2019 v.438 no.1-2 pp. 435-445
ammonium, biodiversity, canopy, ecological differentiation, nitrates, phosphorus, potassium, seed dispersal, seedling growth, seedlings, soil heterogeneity, soil pH, spatial variation, surveys, total nitrogen, tropical rain forests, China
AIMS: In tropical rainforests, seedling performance at fine ecological scales has traditionally been explained by seed dispersal limitation and negative density dependence. Soil properties have strong patch structures at fine scales, and we investigated whether such heterogeneity contributes to seedling coexistence. METHODS: From January 2011 to January 2014, in a one-hectare area of tropical rainforest in Southwest China, we sampled seedlings from ninety-nine 2-m² quadrats, and measured light condition (canopy openness), and the height (>10 cm) of seedlings at bi-monthly intervals. In addition, we measured soil pH, total nitrogen, ammonium, nitrate, and available phosphorus and potassium three times during the survey period. These data were used to examine the effects of soil properties and light on seedling spatial distribution, survival, and growth. RESULTS: Seedling spatial distribution was significantly associated with light and spatial heterogeneity in all the examined soil properties except available K. These fine scale soil properties and light heterogeneity also promoted seedling growth, whereas they had no discernible effects on seedling survival. CONCLUSION: This study highlights the effects of fine scale soil property heterogeneity on seedling spatial distribution and growth, and indicates their importance in the maintenance of seedling biodiversity.