Non-neutral vegetation dynamics.
Abstract
The neutral theory of biodiversity constitutes a reference null hypothesis for the
interpretation of ecosystem dynamics and produces relatively simple analytical descriptions
of basic system properties, which can be easily compared to observations. On the contrary,
investigations in non-neutral dynamics have in the past been limited by the complexity
arising from heterogeneous demographic behaviours and by the relative paucity of detailed
observations of the spatial distribution of species diversity (beta-diversity): These
circumstances prevented the development and testing of explicit non-neutral mathematical
descriptions linking competitive strategies and observable ecosystem properties. Here
we introduce an exact non-neutral model of vegetation dynamics, based on cloning and
seed dispersal, which yields closed-form characterizations of beta-diversity. The
predictions of the non-neutral model are validated using new high-resolution remote-sensing
observations of salt-marsh vegetation in the Venice Lagoon (Italy). Model expressions
of beta-diversity show a remarkable agreement with observed distributions within the
wide observational range of scales explored (5 x 10(-1) m divided by 10(3) m). We
also consider a neutral version of the model and find its predictions to be in agreement
with the more limited characterization of beta-diversity typical of the neutral theory
(based on the likelihood that two sites be conspecific or heterospecific, irrespective
of the species). However, such an agreement proves to be misleading as the recruitment
rates by propagules and by seed dispersal assumed by the neutral model do not reflect
known species characteristics and correspond to averages of those obtained under the
more general non-neutral hypothesis. We conclude that non-neutral beta-diversity characterizations
are required to describe ecosystem dynamics in the presence of species-dependent properties
and to successfully relate the observed patterns to the underlying processes.
Type
Journal articleSubject
BiodiversityBiological Evolution
Ecosystem
Italy
Models, Biological
Plant Development
Plants
Stochastic Processes
Permalink
https://hdl.handle.net/10161/15412Published Version (Please cite this version)
10.1371/journal.pone.0000078Publication Info
Marani, M; Zillio, T; Belluco, E; Silvestri, S; & Maritan, A (2006). Non-neutral vegetation dynamics. PLoS One, 1. pp. e78. 10.1371/journal.pone.0000078. Retrieved from https://hdl.handle.net/10161/15412.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Marco Marani
Adjunct Professor
Sonia Silvestri
Adjunct Associate Professor
Silvestri received her doctoral training in Environmental System Modelling at the
University of Padova, with a focus on remote sensing and the interdependence of salt
marsh morphology and halophytic vegetation. She received her Laurea in Environmental
Sciences from the University Ca’ Foscari in Venice. Silvestri joined the Nicholas
School (Duke University) in 2011, where she teaches “Introduction to Satellite
Remote Sensing” and “Remote Sensing of Coastal Environments&rdq
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