Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Impacts of logging on density dependent predation of dipterocarp seeds in a South East Asian rainforest
AU - Bagchi, Robert
AU - Philipson, Christopher D.
AU - Slade, Eleanor M.
AU - Hector, Andy
AU - Philips, Sam
AU - Villanueva, Jerome F.
AU - Lewis, Owen T.
AU - Lyal, Christopher H. C.
AU - Nilus, Reuben
AU - Madran, Adzley
AU - Scholes, Julie D.
AU - Press, Malcolm C.
PY - 2011/10/17
Y1 - 2011/10/17
N2 - 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.
AB - 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.
KW - Janzen-Connell hypothesis
KW - logging
KW - plant diversity
KW - anthropogenic disturbance
KW - predator satiation
KW - secondary forest
U2 - 10.1098/rstb.2011.0034
DO - 10.1098/rstb.2011.0034
M3 - Journal article
VL - 366
SP - 3246
EP - 3255
JO - Philosophical transactions of the Royal Society of London. Series B, Biological sciences
JF - Philosophical transactions of the Royal Society of London. Series B, Biological sciences
SN - 0080-4622
IS - 1582
ER -