Abstract Detail

Ecological Section

Inman-Narahari, Faith [1], Ostertag, Rebecca [2], Giardina, Christian [3], Cordell, Susan [3], Sack, Lawren [4].

Seedling dynamics in native dominated Hawaiian rain forest.

Seedling regeneration patterns and resource requirements are important determinants of long term forest dynamics. We measured all native tree seedlings within 192 1-m² seedling subplots distributed on a 20×20-m grid system throughout a 4-ha Forest Dynamics Plot on Hawai’i Island in which all adult trees ≥1-cm diameter at breast height have been identified and mapped. About 35% of the regenerating seedlings were the canopy dominant Metrosideros polymorpha (Myrtaceae) and 33% were the subcanopy dominant, Cheirodendron trigynum (Araliaceae); less than 1% were the other major canopy tree, Acacia koa (Fabaceae). Across the eight seedling species, seedling abundance correlated positively with adult tree abundance (R²=0.85: P < 0.001). For two of the four species with abundant seedlings, M. polymorpha and Coprosma rhynchocarpa . (Rubiaceae), the number of seedlings within given 20×20-m quadrats correlated with the number of adults. However, for C. trigynum and Vaccinium calycinum (Ericaceae), there was no relationship between number of seedlings and adults within quadrats. We also measured light (photosynthetically active radiation (PAR)) and recorded the substrate occupied by each seedling to determine the potential importance of micro-habitat on seedling abundance. For all species, seedling abundance within subplots was not correlated with light, possibly reflecting the relatively open canopy and high light availability in this forest (≥10% relative PAR). However, seedling abundance was significantly related to substrate. Most seedlings were found on organic substrates (tree fern logs, tree logs, and root mats), with only one species found disproportionally on mineral soil. These results point to complex contributions of substrate and seed availability in determining seedling abundances in native dominated wet Hawaiian forest.

Broader Impacts:

1 - University of California, Los Angeles, Ecology and Evolutionary Biology, Campus Box 951606, 621 Charles E. Young Dr. S., Los Angeles, CA, 90095-1606, USA
2 - University of Hawaii, Hilo, Biology Department, 200 W. Kawili St., Hilo, HI, 96720, USA
3 - USDA Forest Service, Pacific Southwest Research Station, Institute of Pacific Islands Forestry, 60 Nowelo St., Hilo, HI, 96720, USA
4 - University of California, Los Angeles, Ecology and Evolutionary Biology, 621 Charles E. Young Drive, Los Angeles, CA, 90095, USA

Keywords:
tropical forest
seedling recruitment.

Presentation Type: Oral Paper:Papers for Sections
Session: 21
Location: 552A/Convention Center
Date: Monday, August 2nd, 2010
Time: 5:00 PM
Number: 21006
Abstract ID:436