TY - JOUR
T1 - Disturbance and tropical pioneer species
T2 - Patterns of association across life history stages
AU - Goodale, Uromi M.
AU - Ashton, Mark S.
AU - Berlyn, Graeme P.
AU - Gregoire, Timothy G.
AU - Singhakumara, B. M.P.
AU - Tennakoon, Kushan U.
N1 - Funding Information:
We thank E.B. Goodale, P. Marshall, C.K. Kopp and J. Balch for their comments to improve the manuscript, A.P. Nandamalini, B.W. Somalatha, B.W. Piyaseeli, A.P. Jayarathna, K.D.T. Jayarathna, R. Barr, J. Grimm, K. Ohlson, and C. Martin for their excellent assistance in the field, and S.P.J. Piyadasa, G.S. Ramachandran, S.A.W.S. Kumara and M. Gunadasa for facilitating accommodation at the Sinharaja Field Research Station. The Sri Lanka Forest Department kindly provided permission to conduct the project. This material is based upon work supported by the National Science Foundation and American Association for the Advancement of Sciences, Women in International Scientific Cooperation award, and research awards and fellowships from the Yale University Graduate School of Arts and Sciences, Tropical Resources Institute, Yale Institute for Biospheric Studies and G.P. Berlyn Research Fund.
PY - 2012/8/1
Y1 - 2012/8/1
N2 - Pioneer tree species of tropical rain forests in the seedling and sapling size classes are generally associated with disturbances to the forest canopy. Pioneers have usually been lumped together within the same broad guild. Many studies have demonstrated differentiation of late successional shade-tolerant species within a forest but only a few studies have shown pioneers to be complex in differentiation. Most assume pioneers to be generalist and similar in growth and establishment. It is therefore not well understood, how sympatric pioneer species differ across life history stages in relation to disturbance characteristics such as canopy openness, type, intensity and historical condition of disturbance. Here we studied seedlings, saplings and larger trees of eight pioneer species common in and around the Sinharaja World Heritage Reserve in Sri Lanka to characterize species differences in relation to canopy openness, type and intensity of disturbance. We analyzed canopy hemispherical photographs and conditions of disturbance and assessed the probability of species' occurrence and the relative importance of disturbance characteristics by fitting progressively more complex multinomial logistical regression models. Canopy openness demonstrated the greatest association with seedling and sapling distribution. . Trema orientalis, was found in the highest light conditions, while all other species showed a decrease in the probability of occurrence with increasing canopy openness. For larger trees, the historical condition of disturbance was shown to be a more important factor than the light characteristics. Irrespective of size classes, . T. orientalis and . Macaranga peltata were restricted to high light environments and large disturbances whereas . Macaranga indica, . Dillenia triquetra, . Schumacheria castaneifolia, and . Wendlandia bicuspidata were found in relatively lower light environments and smaller disturbances. . Alstonia macrophylla and . Melastoma malabathricum were able to exist across wide ranging light conditions. In seedlings and saplings, disturbance type was more influential than both the historical condition of disturbance and the intensity of the disturbance, with some evidence that species do occur differentially in certain disturbance types. In summary this study provides evidence that pioneers of all life history stages differentiate in relation to amount of light and disturbance characteristics and that such differentiations are important mechanisms for the coexistence and diversity of early seral tropical tree species. Findings from our study suggests that pioneers used for reforestation and site amelioration need to be selected carefully to match degree of exposure, history and type of disturbance of the site that is to be reforested.
AB - Pioneer tree species of tropical rain forests in the seedling and sapling size classes are generally associated with disturbances to the forest canopy. Pioneers have usually been lumped together within the same broad guild. Many studies have demonstrated differentiation of late successional shade-tolerant species within a forest but only a few studies have shown pioneers to be complex in differentiation. Most assume pioneers to be generalist and similar in growth and establishment. It is therefore not well understood, how sympatric pioneer species differ across life history stages in relation to disturbance characteristics such as canopy openness, type, intensity and historical condition of disturbance. Here we studied seedlings, saplings and larger trees of eight pioneer species common in and around the Sinharaja World Heritage Reserve in Sri Lanka to characterize species differences in relation to canopy openness, type and intensity of disturbance. We analyzed canopy hemispherical photographs and conditions of disturbance and assessed the probability of species' occurrence and the relative importance of disturbance characteristics by fitting progressively more complex multinomial logistical regression models. Canopy openness demonstrated the greatest association with seedling and sapling distribution. . Trema orientalis, was found in the highest light conditions, while all other species showed a decrease in the probability of occurrence with increasing canopy openness. For larger trees, the historical condition of disturbance was shown to be a more important factor than the light characteristics. Irrespective of size classes, . T. orientalis and . Macaranga peltata were restricted to high light environments and large disturbances whereas . Macaranga indica, . Dillenia triquetra, . Schumacheria castaneifolia, and . Wendlandia bicuspidata were found in relatively lower light environments and smaller disturbances. . Alstonia macrophylla and . Melastoma malabathricum were able to exist across wide ranging light conditions. In seedlings and saplings, disturbance type was more influential than both the historical condition of disturbance and the intensity of the disturbance, with some evidence that species do occur differentially in certain disturbance types. In summary this study provides evidence that pioneers of all life history stages differentiate in relation to amount of light and disturbance characteristics and that such differentiations are important mechanisms for the coexistence and diversity of early seral tropical tree species. Findings from our study suggests that pioneers used for reforestation and site amelioration need to be selected carefully to match degree of exposure, history and type of disturbance of the site that is to be reforested.
KW - Canopy hemispheric photography
KW - Disturbance
KW - Life history stages
KW - Pioneers
KW - Restoration ecology
KW - Shade tolerance
UR - http://www.scopus.com/inward/record.url?scp=84861000983&partnerID=8YFLogxK
U2 - 10.1016/j.foreco.2012.04.020
DO - 10.1016/j.foreco.2012.04.020
M3 - Article
AN - SCOPUS:84861000983
SN - 0378-1127
VL - 277
SP - 54
EP - 66
JO - Forest Ecology and Management
JF - Forest Ecology and Management
ER -