Responses of pre‐dispersal seed predators to sequential flowering of Dipterocarps in Malaysia

Significance of seed dispersal by the largest frugivore for large-diaspore trees

How do large-bodied frugivores contribute to seed dispersal of large-diaspore plants? This study examined seed dispersal effectiveness for two large-diaspore tree species, Astrotrichilia asterotricha (AA) and Abrahamia deflexa (AD), in a Madagascan forest. I evaluated fruit removal rates through focal tree observations and factors affecting seedling recruitment up to the 2-year-old seedling stage. I confirmed brown lemur (Eulemur fulvus) as the sole disperser, removing 58.8% and 26.0% of fruits produced by AA and AD. Brown lemurs frequently visited large-crowned AA trees with high density of fallen fruits and more adjacent fruiting trees during seasons with low fruit diversity. Most AA seedlings were removed by predators, although canopy openness slightly improved seedling establishment. Although AD seeds were severely attacked by predators under mother trees, the seedlings survived under dispersal conditions distant from the mother trees, and with low density of diaspores. AD had a higher cumulative probability from fruit removal to seedling recruitment (6.5%) than AA (1.5%) in the first rainy season. This study clarifies the significance of seed dispersal to tree recruitment strategies, which vary among different combinations of tree species and large frugivores, i.e. quantitative dispersal to reach suitable microhabitats, and qualitative dispersal to escape from dangerous zones near mother trees.

What drives food security for wildlife in logged and intact forests of tropical Borneo?

Timber extraction is often cited as detrimental to wildlife ecology. Little information, however, in particular from the Southeast Asian tropics, is available on how exactly logging affects wildlife food security. To address the gap, this paper presents the first high-resolution comparison of fruit production between logged and intact forests in lowland Borneo. In the period of 2004-2008, dry weight of fruit litter was assessed as a proxy for food security of wildlife. The pheno-phases of 1,054 trees in 14 sampling plots were monitored for 54 months. A total of 143,184 fruits from 50 tree families were collected from six sampling transects totalling 810 km in 34 months. Surprisingly, logged forest (mean = 23.3 kg ha^-1, SD = 48.9) produced more fruit litter than intact forest (mean = 16.7 kg ha^-1, SD = 23.3), although the difference is not significant based on Student's t test; t(66) = 0.702, p = 0.485. Pheno-phases could not be entirely explained by rainfall and temperature variables. Some evidence, however, indicates tree species composition, stand structure and sunlight exposure were likely determinants of flowering and fruit litter intensity. All things being equal, results imply selective logging if considerately practiced may increase food security for wildlife. The findings, however, should be interpreted with caution since tropical forest phenology and fruit productivity are also driven by a suite of small-scale edaphic attributes and large-scale spatio-temporal meteorological forcing. Although this research deals mainly with Borneo, the principles discussed and insights offered herein are valuable for furthering conversation around sustainable forestry in tropical Asia and elsewhere globally.