A new approach to spatially explicit modelling of forest dynamics: Spacing, ageing and neighbourhood competition of mangrove trees
Authored by Uta Berger, Hanno Hildenbrandt
Date Published: 2000
DOI: 10.1016/s0304-3800(00)00298-2
Sponsors:
German Federal Ministry of Education and Research (BMBF)
Brazilian National Council for Scientific and Technological Development (CNPq)
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Abstract
This paper presents a new approach to spatially explicit modelling that
enables the influence of neighbourhood effects on the dynamics of
forests and plant communities to be analysed. We refer to this approach
as `field of neighbourhood' (FON). It combines the `neighbourhood
philosophy' of grid-based models with the description of individual
spacing in the `zone of influence' (ZOI) approach. The novel feature of
FON is that modelling of local competition between neighbouring trees is
based on the notion of a field of neighbourhood exerted by each tree.
This field is defined only on the ZOI of a tree and depends on the
distance to the stemming point. For the demonstration of FON's power, a
simulation model (KiWi) was implemented that focuses on the dynamic of
mangrove forests. The realistic self-thinning behaviour of modelled
stands of Avicennia germinans and Rhizophora mangle confirms the
suitability of the FON approach for the description of intra- and
inter-specific competition. In KiWi, mortality is modelled in terms of a
`memory function', i.e. the yearly stem increment of each tree is stored
in its `memory' over a certain time period and determines - as a sign of
vitality - tree mortality. The results of KiWi demonstrate that this
description is sufficient to keep the maximum age of the trees within a
reasonable limit. The model thus manages without a description of
individual tree age. This is an important feature considering the fact
that a direct relationship between tree age and mortality is questioned
and there is no established method as yet for determining the age of
mangrove trees. (C) 2000 Elsevier Science B.V. All rights reserved.
Tags
ecosystems
ecology
pattern
population
growth
Lessons