Plant species coexistence at local scale in temperate swamp forest: test of habitat heterogeneity hypothesis

Abstract

It has been suggested that a heterogeneous environment enhances species richness and allows for the coexistence of species. However, there is increasing evidence that environmental heterogeneity can have no effect or even a negative effect on plant species richness and plant coexistence at a local scale. We examined whether plant species richness increases with local heterogeneity in the water table depth, microtopography, pH and light availability in a swamp forest community at three local spatial scales (grain: 0.6, 1.2 and 11.4 m). We also used the variance partitioning approach to assess the relative contributions of niche-based and other spatial processes to species occurrence. We found that heterogeneity in microtopography and light availability positively correlated with species richness, in accordance with the habitat heterogeneity hypothesis. However, we recorded different heterogeneity-diversity relationships for particular functional species groups. An increase in the richness of bryophytes and woody plant species was generally related to habitat heterogeneity at all measured spatial scales, whereas a low impact on herbaceous species richness was recorded only at the 11.4 m scale. The distribution of herbaceous plants was primarily explained by other spatial processes, such as dispersal, in contrast to the occurrence of bryophytes, which was better explained by environmental factors. Our results suggest that both niche-based and other spatial processes are important determinants of the plant composition and species turnover at local spatial scales in swamp forests.

Native and Alien Plant Species Richness Response to Soil Nitrogen and Phosphorus in Temperate Floodplain and Swamp Forests

“…The high availability of soil phosphorus favors species Urtica dioica during successful development and strong competition [63]. Indeed, clonal species with lateral spreading are able to reallocate resources among individual ramets growing in patches with diverse nutrient-availability [22]. Thus, their competitive advantage at high phosphorus levels can suppress the colonization and successful establishment of other plant species and, consequently, can lead to the species richness decline.…”

“…The carbon to nitrogen (C/N) ratio of soil organic matter is a useful indicator of site quality with effects on both forest species composition and richness [18,19]. However, plant species richness in floodplain forests is also driven by several other environmental factors such as soil moisture and reaction, landscape configuration and dynamic of water regime [20][21][22]. These factors can account for a major part of explained variation in the species richness-environmental relationship [20].…”

Soil phosphorus heterogeneity promotes tree species diversity and phylogenetic clustering in a tropical seasonal rainforest

“…The mean and coefficient of variation (CV =  SD / M , SD  = standard deviation, M  = mean) of AN and EP were calculated to represent the availability and heterogeneity of these nutrients within each plot (Baer, Blair, Collins, & Knapp, 2004; Douda et al., 2012; Holl et al., 2013). The Shapiro–Wilk test was first implemented to evaluate the normal distribution of all variables; all the soil variables within each plot were log‐transformed to promote normality.…”

Testing heterogeneity–diversity relationships in tropical forest restoration

“…Studies across a range of ecosystems, however, show mixed support for the heterogeneity-diversity relationship, and that the relationship commonly varies across spatial scales (Lundholm 2009;Douda et al 2012). Heterogeneity and diversity are often positively correlated, but some studies show no relationship or occasionally negative correlations between resource heterogeneity and species diversity (reviewed in Lundholm 2009).…”

“…Second, dispersal limitation may reduce the available species pool and in turn community composition to a greater degree than niche availability (Tilman 1997;Questad and Foster 2008;Douda et al 2012). There is strong evidence of dispersal limitation at our study site (Cole et al 2010) and other abandoned pastures in the tropics (e.g., Holl 1999;Harvey 2000b;Martinez-Garza and Gonzalez-Montagut 2002;Zahawi and Augspurger 2006), with very few large-seeded, mid-to-late successional species arriving; this limits the trait variation within the available species pool and, therefore, the potential for species to exploit all available niches (Questad and Foster 2008).…”