Impacts of logging on density dependent predation of dipterocarp seeds in a South East Asian rainforest

Bagchi, Robert and Philipson, Christopher D. and Slade, Eleanor M. and Hector, Andy and Philips, Sam and Villanueva, Jerome F. and Lewis, Owen T. and Lyal, Christopher H. C. and Nilus, Reuben and Madran, Adzley and Scholes, Julie D. and Press, Malcolm C. (2011) Impacts of logging on density dependent predation of dipterocarp seeds in a South East Asian rainforest. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 366 (1582). pp. 3246-3255. ISSN 0080-4622

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Abstract

Much of the forest remaining in South East Asia has been selectively logged. The processes promoting species coexistence may be the key to the recovery and maintenance of diversity in these forests. One such process is the Janzen–Connell mechanism, where specialized natural enemies such as seed predators maintain diversity by inhibiting regeneration near conspecifics. In Neotropical forests, anthropogenic disturbance can disrupt the Janzen–Connell mechanism, but similar data are unavailable for South East Asia. We investigated the effects of conspecific density (two spatial scales) and distance from fruiting trees on seed and seedling survival of the canopy tree Parashorea malaanonan in unlogged and logged forests in Sabah, Malaysia. The production of mature seeds was higher in unlogged forest, perhaps because high adult densities facilitate pollination or satiate pre-dispersal predators. In both forest types, post-dispersal survival was reduced by small-scale (1 m2) conspecific density, but not by proximity to the nearest fruiting tree. Large-scale conspecific density (seeds per fruiting tree) reduced predation, probably by satiating predators. Higher seed production in unlogged forest, in combination with slightly higher survival, meant that recruitment was almost entirely limited to unlogged forest. Thus, while logging might not affect the Janzen–Connell mechanism at this site, it may influence the recruitment of particular species.

Item Type:
Journal Article
Journal or Publication Title:
Philosophical transactions of the Royal Society of London. Series B, Biological sciences
Subjects:
?? janzen-connell hypothesisloggingplant diversityanthropogenic disturbancepredator satiationsecondary forest ??
ID Code:
69235
Deposited By:
Deposited On:
16 Apr 2014 11:24
Refereed?:
Yes
Published?:
Published
Last Modified:
15 Jul 2024 14:36