Ecosystems

, Volume 13, Issue 2, pp 286–301

A Canopy Trimming Experiment in Puerto Rico: The Response of Litter Invertebrate Communities to Canopy Loss and Debris Deposition in a Tropical Forest Subject to Hurricanes

  • Barbara A. Richardson
  • Michael J. Richardson
  • Grizelle González
  • Aaron B. Shiels
  • Diane S. Srivastava
Article

DOI: 10.1007/s10021-010-9317-6

Cite this article as:
Richardson, B.A., Richardson, M.J., González, G. et al. Ecosystems (2010) 13: 286. doi:10.1007/s10021-010-9317-6

Abstract

Hurricanes cause canopy removal and deposition of pulses of litter to the forest floor. A Canopy Trimming Experiment (CTE) was designed to decouple these two factors, and to investigate the separate abiotic and biotic consequences of hurricane-type damage and monitor recovery processes. As part of this experiment, effects on forest floor invertebrate communities were studied using litterbags. Canopy opening resulted in increased throughfall, soil moisture and light levels, but decreased litter moisture. Of these, only throughfall and soil moisture had returned to control levels 9 months after trimming. Canopy opening was the major determinant of adverse changes in forest floor invertebrate litter communities, by reducing diversity and biomass, irrespective of debris deposition, which played a secondary role. Plots subjected to the most disturbance, with canopy removed and debris added, had the lowest diversity and biomass. These two parameters were higher than control levels when debris was added to plots with an intact canopy, demonstrating that increased nutrient potential or habitat complexity can have a beneficial effect, but only if the abiotic conditions are suitable. Animal abundance remained similar over all treatments, because individual taxa responded differently to canopy trimming. Mites, Collembola, and Psocoptera, all microbiovores feeding mainly on fungal hyphae and spores, responded positively, with higher abundance in trimmed plots, whereas all other taxa, particularly predators and larger detritivores, declined in relative abundance. Litterbag mesh size and litter type had only minor effects on communities, and canopy trimming and debris deposition explained most variation between sites. Effects of trimming on diversity, biomass, and abundance of some invertebrate taxa were still seen when observations finished and canopy closure was complete at 19 months. This suggests that disturbance has a long-lasting effect on litter communities and may, therefore, delay detrital processing, depending on the severity of canopy damage and rate of regrowth.

Keywords

canopy gaps community composition forest manipulation fungi litterbags relative abundance 

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Barbara A. Richardson
    • 1
    • 2
  • Michael J. Richardson
    • 1
    • 2
  • Grizelle González
    • 3
  • Aaron B. Shiels
    • 4
    • 5
  • Diane S. Srivastava
    • 6
  1. 1.EdinburghUK
  2. 2.Luquillo LTER, Institute for Tropical Ecosystem Studies, University of Puerto Rico at Rıo PiedrasSan JuanUSA
  3. 3.International Institute of Tropical Forestry, USDA Forest Service, Jardín Botánico SurSan JuanUSA
  4. 4.Institute for Tropical Ecosystem StudiesUniversity of Puerto Rico at Río PiedrasSan JuanUSA
  5. 5.University of Hawai`i at ManoaHonoluluUSA
  6. 6.Department of Zoology and Biodiversity Research CentreUniversity of British ColumbiaVancouverCanada