Forest Succession in Tropical Hardwood Hammocks of the Florida Keys: Effects of Direct Mortality from Hurricane Andrew

• Published in: Biotropica Vol. 33; no. 1; pp. 23 - 33
• Main Authors: Ross, MS, Carrington, M, Flynn, L J, Ruiz, P L
• Format: Journal Article
• Language: English
• Published: 01.03.2001
• Subjects: USA, Florida
• ISSN: 0006-3606
• DOI: 10.1043/0006-3606(2001)033(0023:FSITHH)2.0.CO;2

A tree species replacement sequence for dry broadleaved forests (tropical hardwood hammocks) in the upper Florida Keys was inferred from species abundances in stands abandoned from agriculture or other anthropogenic acitivities at different times in the past. Stands were sampled soon after Hurricane Andrew, with live and hurricane-killed trees recorded separately; thus it was also possible to assess the immediate effect of Hurricane Andrew on stand successional status. We used weighted averaging regression to calculate successional age optima and tolerances for all species, based on the species composition of the pre-hurricane stands. Then we used weighted averaging calibration to calculate and compare inferred successional ages for stands based on (1) the species composition of the pre-hurricane stands and (2) the hurricane-killed species assemblages. Species characteristic of the earliest stages of post-agricultural stand development remains a significant component of the forest for many years, but are gradually replaced by taxa not present, even as seedlings, during the first few decades. This compositional sequence of a century or more is characterized by the replacement of deciduous by evergreen species, which is hypothesized to be driven by increasing moisture storage capacity in the young organic soils. Mortality from Hurricane Andrew was concentrated among early-successional species, thus tending to amplify the long-term trend in species composition.