Resource-based niches provide a basis for plant species diversity and dominance in arctic tundra

Abstract

Ecologists have long been intrigued by the ways co-occurring species divide limiting resources. Such resource partitioning, or niche differentiation, may promote species diversity by reducing competition. Although resource partitioning is an important determinant of species diversity and composition in animal communities, its importance in structuring plant communities has been difficult to resolve. This is due mainly to difficulties in studying how plants compete for below-ground resources. Here we provide evidence from a 15N-tracer field experiment showing that plant species in a nitrogen-limited, arctic tundra community were differentiated in timing, depth and chemical form of nitrogen uptake, and that species dominance was strongly correlated with uptake of the most available soil nitrogen forms. That is, the most productive species used the most abundant nitrogen forms, and less productive species used less abundant forms. To our knowledge, this is the first documentation that the composition of a plant community is related to partitioning of differentially available forms of a single limiting resource.

How does pedogenesis drive plant diversity?

“…In this review, we present a set of older [11][12][13] and more recent [20,21,38,49] hypotheses that describe how longterm pedogenesis can drive local plant species diversity. We believe that soil chronosequences can be used to quantify the relative importance of the different mechanisms that affect plant species diversity, and how they depend on environmental context.…”

“…inositol phosphates, phospholipids and phosphonates) forms that plants can access via specialized root strategies (e.g., mycorrhizas, phosphatase enzymes, and carboxylate exudation) [19,20]. This raises the possibility that partitioning of different forms of N or P can contribute to plant species coexistence, even if all species within a community are limited by the same nutrient [20,21]. In other words, a greater diversity of N or P forms in soils might allow a greater number of plant species to coexist.…”

Interactive effects between plant functional types and soil factors on tundra species diversity and community composition

“…Vascular community composition was mainly related to soil acidity, temperature, moisture, and nitrogen content. These soil variables can modify the nutrient and water availability, which discriminate among vascular species according to their root characteristics (McKane et al., 2002). Nonvascular composition was related to soil moisture, acidity, temperature, ALT, nitrogen content, and cellulose‐to‐lignin and carbon‐to‐nitrogen ratios.…”

Two Decades of Experimental Manipulations of Heaths and Forest Understory in the Subarctic

“…One reason may be that plants partition the dissolved N, so that the most productive plants take up the most abundant form of N, while less productive species tap less abundant forms (McKane et al 2002). The availability of N in different forms (NO 3 -, NH 4 ?…”