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Diversity change in forest plots of Blue Mountains, Jamaica

Citation

Godsoe, William; Bellingham, Peter; Moltchanova, Elena (2021), Diversity change in forest plots of Blue Mountains, Jamaica, Dryad, Dataset, https://doi.org/10.5061/dryad.sxksn033s

Abstract

Beta diversity describes the differences in species composition among communities. Changes in beta diversity over time are thought to be due to selection based on species’ niche characteristics. For example, theory predicts that selection that favours habitat specialists will increase beta diversity. In practice, ecologists struggle to predict how beta diversity changes. To remedy this problem, we propose a novel solution that formally measures selection’s effects on beta diversity. Using the Price equation, we show how change in beta diversity over time can be partitioned into fundamental mechanisms including selection among species, variable selection among communities, drift, and immigration. A key finding of our approach is that a species’ short-term impact on beta diversity cannot be predicted using information on its long-term environmental requirements (i.e. its niche). We illustrate how our approach can be used to partition causes of diversity change in a montane tropical forest before and after an intense hurricane. Previous work in this system highlighted the resistance of habitat specialists and the recruitment of light-demanding species but was unable to quantify the importance of these effects on beta diversity. Using our approach, we show that changes in beta diversity were consistent with ecological drift. We use these results to highlight the opportunities presented by a synthesis of beta diversity and formal models of selection.

Methods

This is an example dataset for a mathematical paper, using data that was originally collected from an published empirical paper (Tanner and Bellingham 2006). 

Tanner, E. V. J., and P. J. Bellingham. 2006. Less diverse forest is more resistant to hurricane disturbance: evidence from montane rain forests in Jamaica. Journal of Ecology 94:1003-1010.

From the text of the current manuscript:

We illustrate how our approach can be used to measure the causes of diversity change in nature using data from a montane tropical forest during recovery from hurricane damage. Example analyses are provided in (appendix S3). Tanner (1977) sampled forests in four sites within 25–175 m of each other that differed in topography and soil nutrient availability on and near the main ridge of the Blue Mountains of Jamaica (18°05′ N, 76°39′ W; 1580–1600 m). The Mor ridge site (hereafter Mor) has low soil nutrient availability, with low alpha diversity and several habitat specialists (Tanner 1977). The three other sites are more fertile, include many habitat generalists, and have higher alpha diversity: Col forest, Wet Slope forest, and Mull Ridge forest (hereafter Col, Slope and Mull, respectively; Tanner and Bellingham 2006). At each site all tree individuals ≥3 cm in diameter at 1.3 m height (dbh) were identified, tagged, and measured during an initial survey in 1974.

These sites were re-censused in 1984, then hit by Hurricane Gilbert in 1988, considered the most powerful hurricane in the Caribbean in the 20th century, and then re-censused in 1994 (Tanner and Bellingham 2006). The hurricane caused increased tree mortality, both immediately and over several years as a result of stem damage (Bellingham et al. 1992, Tanner et al. 2014), and widespread defoliation, increasing the light available in the forest floor for approximately three years (Bellingham et al. 1996). As a result, alpha diversity increased in some sites, which Tanner and Bellingham (2006) hypothesized was due to the recruitment of light-demanding species, but they did not quantify the contributions of these to overall species diversity.