Competitive dominance in a secondary successional rain-forest community in Borneo

Abstract

Abstract:Competitive interactions among pioneer species may have a significant impact on the course of secondary succession in tropical rain forests. We predicted that the outcome of competitive interactions in early succession would vary with soil nutrient availability. To test this hypothesis we grew seven pioneer tree species alone and in dense competitive mixtures, with four nutrient treatments: no nutrient addition, and N, P, and N plus P addition. Performance of plants grown alone and in mixtures was strongly nutrient limited. However, contrary to expectation, the competitive hierarchy among the seven species was almost identical among the four nutrient treatments. The dominant species, Melastoma malabathricum, accounted for > 70% of total stand biomass in all nutrient treatments. Seedlings of this species had higher rates of gas exchange and initial growth, and lower root allocation than the other species. Profiles of light availability within the competitive stands indicated that light levels at ground level were well above levels at which pioneer species can successfully survive and grow, yet seedlings of species other than Melastoma remained stunted. Leaf N concentrations in all stands were 25-55% reduced by competitive interactions, and N addition increased relative competitive performance in only Melastoma suggesting that Melastoma was particularly effective at N acquisition, limiting nutrient uptake by the other species. Toward the end of the experiment individuals of Melastoma began to reproduce, suggesting that the competitive hierarchy would have changed in a longer-duration experiment.

Disturbance and tropical pioneer species: Patterns of association across life history stages

“…What studies have been conducted were in Malaysian mixed dipterocarp forests (Davies, 1998;Davies et al, 2001;Davies and Semui, 2006). In Sri Lanka, where the rainforests are at a critically low level of 9% of their original extent (Ministry of Agriculture Land and Forestry, 1995) and are dwindling further due to clearing for agriculture (À1.1% per year, FAO, 2011), it is important to refine our knowledge of pioneer species' site specificity and their ability to be used in facilitating establishment of second growth (Menalled et al, 1998) or plantings of slower growing more shade tolerant tree species .…”

“…Pioneers that germinate and establish in disturbances that create small canopy openings also have to overcome shady conditions from branch extension and canopy closure (Young and Hubbell, 1991). Pioneers in large openings face competition from their own age cohort and ecological group, more than competition from the surrounding canopy vegetation (Davies and Semui, 2006). Further, as pioneers increase in height, they are exposed to longer durations of direct sunlight as they are closer to the top layers of the forest canopy and light intensity is not limited by extinction in successive layers of foliage (Kitajima, 2005).…”

Arthropod diversity in pristine vs. managed beech forests in Transcarpathia (Western Ukraine)

“…This fascinating group is of prime conservation concern (Speight, 1989;Ranius and Jansson, 2000;Simila et al, 2002;Müller et al, 2005a;Davies and Semui, 2006;Müller and Gossner, 2010;Lachat et al, 2012;Müller et al, 2013). Of 1377 saproxylic beetle species known for Germany, 115 species (8%) are considered Urwald relict species (Müller et al, 2005a).…”

Whole‐canopy nitrogen‐use efficiency of pioneer species in early secondary forest succession in Vietnam

“…Since Melastoma candidum is a shrub, its inherent architecture inhibits it from growing tall, it could not reach the most illuminated layers of the canopy by growing tall like the other species. Instead, it produced many branches that were all directed skywards, and leaves were placed at the growing tips of these branches (also found by Davies and Semui 2006) in the most illuminated part of its crown, thereby increasing light capture per unit leaf area (Van Kuijk et al 2008). More than 70% of the leaves were placed horizontally, which is also favorable for light capture (Monsi and Saeki 1953;Hikosaka and Hirose 1997;Muraoka et al 1998;Falster and Westoby 2003).…”