vol. 163, no. 5
the american naturalist
A Putative Mechanism for Bog Patterning
S. C. Dekker,
M. J. Wassen,
A. W. M. Verkroost,
and M. F. P. Bierkens
1. Department of Environmental Sciences, Utrecht University,
Heidelberglaan 2, 3584 CS Utrecht, The Netherlands;
2. Department of Physical Geography, Utrecht University,
Heidelberglaan 2, 3584 CS Utrecht, The Netherlands
Submitted August 7, 2003; Accepted December 3, 2003;
Electronically published May 4, 2004
The surface of bogs commonly shows various spatial
vegetation patterning. Typical are “string patterns” consisting of reg-
ular densely vegetated bands oriented perpendicular to the slope.
Here, we report on regular “maze patterns” on Fat ground, consisting
of bands densely vegetated by vascular plants in a more sparsely
vegetated matrix of nonvascular plant communities. We present a
model reproducing these maze and string patterns, describing how
nutrient-limited vascular plants are controlled by, and in turn control,
both hydrology and solute transport. We propose that the patterns
are self-organized and originate from a nutrient accumulation mech-
anism. In the model, this is caused by the convective transport of
nutrients in the groundwater toward areas with higher vascular plant
biomass, driven by differences in transpiration rate. In a numerical
bifurcation analysis we show how the maze patterns originate from
the spatially homogeneous equilibrium and how this is affected by
changes in rainfall, nutrient input, and plant properties. Our results
con±rm earlier model results, showing that redistribution of a lim-
iting resource may lead to ±ne-scale facilitative and coarse-scale com-
petitive plant interactions in different ecosystems. Self-organization
in ecosystems may be a more general phenomenon than previously
thought, which can be mechanistically linked to scale-dependent fa-
cilitation and competition.
hydrology, nutrient limitation, ombrotrophic, self-
organization, solute transport, spatial patterns, vegetation patterns.
The surface of bogs in North America and Eurasia com-
monly shows various spatial patterning of hummocks and
* E-mail: firstname.lastname@example.org.
Am. Nat. 2004. Vol. 163, pp. 699–708.
2004 by The University of Chicago.
0003-0147/2004/16305-40052$15.00. All rights reserved.
hollows (Sakaguchi 1980; Lindsay et al. 1985; Belyea and
Lancaster 2002). Characteristic are the “string patterns”
(Sakaguchi 1980; ²oster et al. 1983) consisting of regular
densely vegetated bands (hummocks forming ridges) ori-
ented perpendicular to the slope, alternating with wetter
zones that are more sparsely vegetated (hollows forming
pools). Current theoretical and empirical investigations
show that spatial patterning in itself could be explained
by a positive feedback between total plant productivity and
thickness of the acrotelm (upper layer of peat) on slightly
elevated, dryer sites, mainly because of increased produc-