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Scaling Biodiversity Workshop Abstracts
(names of speakers are in alphabetical order)
Andrew P. Allen
Department of Biology, University of New Mexico, USA ([email protected])
The Role of Temperature in the Origin and Maintenance of Biodiversity
The mechanisms responsible for latitudinal and elevational gradients in biodiversity are still poorly
understood. Mechanistic understanding will require theory that links short-term species coexistence to
long-term speciation-extinction dynamics. The strength and consistency of global diversity gradients
in relation to temperature suggests a mechanistic link between the two variables. Species diversity
increases exponentially with temperature for all major groups of terrestrial, freshwater, and marine
ectotherms. I will present a theoretical framework for the origin and maintenance of biodiversity based
on the effects of body size and temperature on biological rates and times. I will present data showing
the potential of this framework for linking population genetics, community ecology, and
macroevolution. The primary motivations for this work are to better understand and predict changes in
biodiversity along temperature gradients, and more generally, to better understand the forces that
control the origin and maintenance of species.
Brendan Bohannan
Stanford University, USA ([email protected])
Patterns in the Biodiversity of Bacteria and Archaea
Despite their ecological importance, very little is known regarding patterns of bacterial and archaeal
diversity or the processes that may determine these patterns. This is due to both historical problems in
measuring microbial diversity and the disciplinary boundaries that tend to separate microbiologists
from ecologists. However, recent advances in molecular techniques that allow a more thorough
detection of bacteria and archaea in nature have made it now possible to examine such patterns and
processes. In fact, very recent studies of bacteria and archaea have revealed a number of patterns in
their diversity, including species-area patterns, species-energy patterns, and patterns along
environmental gradients. From these recent studies a preliminary picture is emerging: bacterial and
archaeal diversity may exhibit regular patterns, and in some cases these patterns may be qualitatively
similar to those observed for plants and animals. This new understanding of microbial biodiversity
presents a unique opportunity to more fully integrate bacteria and archaea into the general science of
ecology.
Luís Borda-de-Água and Stephen P. Hubbell
Department of Plant Sciences, University of Georgia, Athens, Georgia, USA.
([email protected])
The effect of short and long-distance dispersal on the scaling of species diversity and abundance
The unified neutral theory (UNT) in ecology is a dynamical theory of relative species abundance and a
set of null hypotheses for the assembly of communities under the assumption that trophically similar
species are symmetric. The symmetry assumption is that, to a first approximation, ecologically similar
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species are demographically equivalent on a per capita basis in birth and death rates, rates of dispersal,
and in the probability of speciation. Previous work on the UNT did not explicitly consider the effect of
the shape of the dispersal kernel on the distribution and abundance of species. Which dispersal kernel
is used can profoundly affect both local and large-scale patterns of species diversity and abundance.
Here we model dispersal using Lévy-stable distributions. The scaling properties of Lévy-stable
distributions have long been studied in research on fractals but have seldom been applied in ecology.
We discuss in particular the implications of long distance dispersal to the species richness and species
abundance distributions on local and regional scales. Although species richness and the size of the
community have for long being explored (species area relationship), the scaling properties of the
species abundance distributions as s function of dispersal have received much less attention. The
symmetric UNT describes the consequences for community assembly of pure ecological drift
(demographic stochasticity) accompanied by random dispersal and speciation. As such, the UNT is
useful in generating quantitative null hypotheses for testing how much symmetry-breaking is actually
required to explain observed patterns of species abundance and diversity. The UNT can also be used to
estimate the proportion of variance in species abundance that can be ascribed to ecological drift, and
what cannot.
James H. Brown
SFI and Department of Biology, University of New Mexico, USA ([email protected])
A metabolic theory of ecology: from microbes to monsters, molecules to ecosystems
Metabolism provides a basis for using first principles of physics, chemistry, and biology to link the
biology of individual organisms to the ecology of populations, communities, and ecosystems.
Metabolic rate, the rate at which organisms take up, transform, and expend energy and materials, is the
most fundamental biological rate. We have developed a quantitative theory for how metabolic rate
varies with body size and temperature. Metabolic theory predicts how metabolic rate, by setting the
rates of resource uptake from the environment, and resource allocation to survival, growth, and
reproduction, controls ecological processes at all levels of organization from individuals to the
biosphere. Examples include:
1) life history attributes, including development rate, mortality rate, age at maturity, lifespan, and
population growth rate,
2) population interactions, including carrying capacity, rates of competition and predation, and
patterns of species diversity, and
3) ecosystem processes, including rates of biomass production and respiration, and patterns of trophic
dynamics.
Data compiled from the ecological literature strongly support the theoretical predictions. Eventually,
metabolic theory may provide a conceptual foundation for much of ecology, just as genetic theory
provides a foundation for much of evolutionary biology.
Jerome Chave
CNRS, Laboratoire Evolution et Diversité Biologique, Université Paul Sabatier, Tolouse, France
([email protected])
Spatial scaling in tropical forest trees: the importance of sampling effort and of phylogenetic structure
The high local biodiversity of tropical trees has been amply documented, but beta-diversity -- how
species composition changes with geographical distance -- has received much less attention. Recently,
a number of studies have greatly contributed to bridge this gap, using new field data and statistical
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methods. All of these studies potentially suffer from two important drawbacks: they are based on
inventories of a few small-sized plots, unlikely to represent the entire variability at larger spatial
scales; and they rest on species identifications that vary considerably in quality among researchers,
among plant families, and among herbaria. I address the first issue through results from a recent
rarefaction analysis of a network of permanent plots. I show how the correlation of floristic similarity
with geographical distance and environmental variables varies with the sampling effort. For the second
issue, I introduce a different measure of floristic similarity based not only on species-level
information, but on the whole phylogenetic structure of the species assemblage. This measure of
phylogenetic relatedness can be calibrated using datasets poorly resolved at the species level, such as
forestry inventories. Naturally, further progress in this area still critically depends on the development
of networks of permanent plots in the tropics, of regional floras, and on faster and easier access to
herbarium information.
Andrew Clarke
Biological sciences, British Antarctic Survey, NERC, Cambridge, UK ([email protected])
Temperature, energy and diversity
Explanations for global patterns of diversity are many and varied. Amongst the most popular have
been those invoking temperature, climate or energy as the main drivers of macroecological patterns of
diversity, both on land and in the sea. These are often referred to collectively under the broad heading
of the species/energy hypothesis. In fact this is not a single, or simple hypothesis, but rather a broad
suite of different hypotheses utilising quite different meanings of the term ‘energy’. The most
successful of these hypotheses has undoubtedly been that linking terrestrial angiosperm diversity to
climate. More recently the metabolic theory of ecology (MTE) has proposed a direct control of
ectotherm diversity by environmental temperature. In this presentation I will discuss these various
forms of energy, so that we can distinguish critically between them as potential drivers of diversity
patterns. The various species/energy hypotheses differ in their success at predicting macroecological
patterns of diversity, but all of them suffer from the disadvantage that they lack a clear testable
mechanism for linking the driver from the physical environment to diversity as against simply biomass
or abundance.
David Currie
Biology Department, University of Ottawa, Canada ([email protected])
Spatial scale and richness-environment relationships
Spatial variation in species richness usually covaries strongly with environmental characteristics.
These relationships often differ among studies at different spatial scales. Is this because the variance
of environmental variables changes with scale? Does the spatial structure (autocorrelation) of
diversity and/or environmental variables change with scale? Does the functional form of richnessenvironment relationships change with scale? To answer these questions, I compared broad-scale
patterns of bird and angiosperm richness over different spatial extents and grain sizes. Preliminary
analyses suggest that the functional relationships among variables do not change with spatial extent,
but they do change with grain. Spatial autocorrelation also depends upon grain size. Characterizing
the dependence of richness-environment relationships on grain remains a challenge because of lack of
appropriate data.
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Kevin J. Gaston
Biodiversity and Macroecology Group, Department of Animal & Plant Sciences, University of
Sheffield, UK ([email protected])
The scaling of spatial turnover
When contrasted with the attention paid to spatial patterns of species richness, patterns of variation in
beta diversity and spatial turnover have been relatively neglected. Nonetheless, turnover in species
identities lies at the heart of many ecological phenomena, including the control of diversity. Here, we
explore the varied interpretations of what constitutes spatial turnover and their relations. We then
employ empirical data to examine a number of issues in the scaling of spatial turnover. First, we
investigate the suggestion that high levels of turnover promote species richness. Second, we explore
the phenomena of distance decay, the prediction that turnover scales positively with distance. Third,
we provide one of the first and most detailed multivariate analyses of the environmental factors
associated with spatial turnover. Each of these issues is investigated across a wide range of spatial
scales. We conclude with recommendations for the measurement and analysis of spatial turnover.
Jessica L. Green
University of California at Merced, USA ([email protected])
Spatial scaling of microbial eukaryote diversity
Microorganism assemblages are notably diverse at small scales. If they are strongly spatially
differentiated, microorganisms will represent the majority of earth’s biodiversity. But our
understanding of the spatial structure of diversity remains limited to macroorganisms. Using the
largest spatially-explicit microbial genetic data set available (>1,000,000 sample pairs), we present the
first quantitative estimates of microbial community turnover at local and regional scales. Microbial
turnover rates were small across large geographic distances and strikingly consistent within different
habitats. At a fixed geographic distance, microbial communities were not always more similar within
one habitat type than between different habitats. We show how turnover patterns can be used to
project microbial taxa-area relationships up to whole continents. Our results indicate that similar to
macroorganisms, microorganisms are not randomly distributed, but rather exhibit spatial structure
across scales spanning over 15 orders of magnitude.
John Harte
Energy and Resources Group and the Ecosystem Sciences Division of the College of Natural
Resources, University of California, Berkeley, USA ([email protected])
A unified theory of spatial structure in ecological communities at multiple spatial scales
A new theory of the abundance and distribution of species predicts a wide variety of measures of
spatial pattern in vegetation communities across a large range of spatial scales. Starting only with the
observed species-abundance distribution at some largest spatial scale, and with no adjustable
parameters, the theory predicts at each smaller scale the species-abundance distribution, the speciesarea and endemics-area relationships, the spatial abundance distributions of each species and of the
community, the relationship between range-size and census-cell area, an index of aggregation, and the
dependence of species turnover on inter-patch distance and patch area. Tests with census data from
wet and dry tropical forest sites and from a serpentine meadow indicate the theory predicts these
spatial metrics remarkably accurately, with the exception of the spatial distributions of the most
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abundant species. The theory forbids scale-independence and associated power-law behaviors at the
individual species level, and yields a power-law species-area relationship only over a limited scale
range and only under very constrained conditions on the species-abundance distribution. By
excluding any explicit information about birth, death, migration, dispersal, competition, predation, and
density-dependence, we have created a simple theoretical framework, the failures of which can
highlight the circumstances in which explicit representation of those biological mechanisms are
needed to explain spatial patterns.
Fangliang He and Rick Condit
Department of Renewable Resources, University of Alberta, Edmonton, Canada
([email protected])
The distribution of species: occupancy, scale and rarity
The distribution of a species in space as recorded by a black and white map with black representing
the presence and white the absence is fundamental biogeographic data. Distribution data have been
widely used to address many important macroecological questions – evolutionary dynamics of species
ranges, species-habitat association, effects of climate change, patterns of species diversity and
conservation. Although at first glance data on distribution seemingly appear easy to gather and
straightforward to understand, our knowledge about the properties of distribution is actually very
limited. For example, there even lacks consensus on questions as basic as how the distribution of a
species may be defined and measured, let alone other more complex theoretical and applied questions.
The poor understanding of the distribution of species is probably in one part attributed to the numerous
forms of distribution and in other part to the fact that distribution and its measurements are scaledependent. It is therefore essential to investigate the scale-dependence of distribution in order to gain
better understanding of species distribution. This study aims to contribute to improving our knowledge
on species distribution from answering three questions. (1) How does the distribution of species
change across spatial scales? (2) Are there any general scaling relationships that may underlie the
various forms of distribution? (3) Are there differences in the distribution between rare and common
species?
Analytical and empirical approaches are used to address the above questions. The data
analyzed include simulated and observed distributions with spatial scales differing in several orders of
magnitude from locally mapped forest stands to distributions at the regional scale. Results show that
distributions of species vary substantially from one scale to another. Few species are fractal in
distribution, most are more aggregated than fractal geometry predicts. Although species do not follow
fractal distribution, there does exist a very general and robust scaling relationship across spatial scales
as predicted by a modified Nachman model, taking the form:  log( 1  p )  ca  , where p is the
proportion of occupied area (or called occupancy), a is the size of the map cell, and c
parameters. The association of the two scaling parameters with rarity and commonness of species is
analyzed, and the implications of this scaling relationship to patterns of species diversity (e.g., the
species-area relationship) and conservation are discussed.
Tomás Herben
Department of Botany, Faculty of Science, Charles University, Czech Republic
([email protected])
Species richness and invasibility of communities: a neutral model
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One of the general ecological patterns is the success of exotic species on oceanic islands. In general
terms it is widely accepted that this is due to impoverishment of island biotas due to limited
immigration; it has been proposed that examination of such invasion patterns can shed light on the
processes structuring island communities. Here I examine whether patterns of invasion on islands can
be predicted by neutral models. I used a simple neutral model based on drawing individuals from two
pools of identical species (native and exotic) and lottery processes of disturbance and local growth. As
an extension of the neutral model, I also examined effects of variation in population growth rates.
Smaller pool of native species was assumed to be the only difference between islands and continents.
While a completely neutral model failed to produce the invasion patterns of islands, a model with nonzero variation in population growth rates consistently predicted higher susceptibility of island
assemblages to invasions. The neutral process of drawing species from smaller species pools produces
typically assemblages with smaller mean population growth rate, which are less likely to block
spreading of random invaders. Non-zero variation in population growth rates also changes neutral
prediction of abundance distribution curves from logseries to lognormal, thus predicting fewer rare
species than a fully neutral model.
Timothy H. Keitt, Naiara Sardinha-Pinto and Evan P. Economo
Section of Integrative Biology, University of Texas, Austin, Texas, USA.
([email protected])
Hierarchical Analysis of Community Dissimilarity
Hierarchical analysis of pattern generally falls within three categories: 1) lagged differences typical of
geostatistics, 2) hierarchical accumulation (nested or scaled windows) often used in fractal analysis,
and 3) hierarchical gradient analysis which interleaves accumulation and differencing such as in
wavelet analysis. Species-area analysis falls in the second category. In nested species-area analysis,
the union of the local species lists is enumerated at each scale. However, there is nothing particularly
unique or profound about species-area relationships. Lagged differencing and hierarchical gradient
analysis may equally be applied, and in many cases may be more powerful in detecting scale-specific
patterns. The lagged geostatistical approach has been extensively discussed elsewhere, however
hierarchical gradient analysis has received little attention from community ecologists. We develop a
wavelet-like transform for analyzing biodiversity data and explore its properties in comparison to other
methods. We apply the technique to tree-plot data from Barro Colorado Island, Panama.
Pavel Kindlmann
Theoretical and Evolutionary Ecology Section, Faculty of Biological Sciences, University of
South Bohemia, České Budějovice, Czech Republic ([email protected])
Inverse latitudinal trends in species diversity and in pollination success
In a previously presented model (Dixon et al., 1987, Am. Nat. 129: 580-592), it was suggested that the
regional species diversity of aphids was maximal at some intermediate plant species richness, and
declined in areas of high vegetational complexity. This pattern, in apparent contrast to more mobile
herbivorous insects such as butterflies, implies that aphid speciation has been limited by aphid's weak
locomotory powers to the exploitation of plant resources, which are readily located. As vegetation
types increase in species complexity, the mean distance between individuals of the same species
increases, and the necessary search effort increases. This model is a simple and powerful indicator of
the evolutionary constraints acting upon these insects. Here I generalize this model to other groups
and extend its predictions to latitudinal trends in pollination success in plants.
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William Kunin
Earth & Biosphere Institute, Faculty of Biological Sciences, University of Leeds, UK
([email protected])
Scaling populations and extinctions
Until recently, most analyses of population dynamics have treated populations, implicitly, as spatially
uniform and subject to perturbations that were random in time and space. Some progress has been
made in analysing the effects of temporal autocorrelation in extinction models, and results to-date
suggest profound effects on extinction probabilities. The effects of spatial autocorrelation may be
equally strong, but have only begun to be explored. Both biological populations and the disturbance
processes that impact upon them are patchy on a wide range of spatial scales. This talk will focus on
two inter-related aspects of the topic: the effect of the spatial pattern of local extinction on global
extinction risk, and the effect of local extinction on spatial population patterning (and vice versa).
There is strong evidence from a range of systems that extinctions are spatially aggregated, and
simulations suggest that this should result in increased global extinction risk and alterations in
conservation strategies. The spatial scaling of species distributions is highly correlated with past
extinction rates, and may also allow prediction of future distributional change.
Jack J. Lennon, William E. Kunin & Stephen Hartley
Centre for Biodiversity and Conservation, School of Biology, University of Leeds, UK
([email protected])
Fractals, the connection between species distribution and species diversity patterns, and the speciesarea relationship
Recently, our understanding of the species-area relationship and the spatial scaling properties of
species distribution patterns has been invigorated using the concept of Fractals and self-similarity.
But are species distributions really Fractal? Here we consider a statistical test for fractality (selfsimilarity) in species distribution patterns and introduce a simple way of describing departures from
fractality, focusing on the usefulness of fractal patterns as null models. We then discuss the particular
properties of species area relationships and species distribution patterns that may show self-similarity.
Finally, we also demonstrate how the spatial scaling properties of species distribution patterns can
vary in space and also reflect the commonness/rarity of the species involved.
Pablo Marquet
Center for Advanced Studies in Ecology and Biodiversity (CASEB) and Departamento de
Ecologia, Pontificia Universidad Catolica de Chile, Santiago, Chile ([email protected])
Scaling biodiversity extremes
Most of what we know about empirical patterns of biodiversity scaling is based on “average
situations” emphasizing what is to be expected over the question of what is actually possible.
Interestingly, theoretical models such as those put forward under the metabolic theory of ecology do in
fact say more about limits to biodiversity scaling instead of average situations. In this presentation we
claim that a large part of the interesting biology is at the extremes. To make our case, we discuss some
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of the theoretical foundations for extreme value analysis of biodiversity by focusing on the scaling of
body size extremes, abundance extremes and diversity extremes.
Neo D. Martinez, Eric L. Berlow, Ulrich Brose, Jennifer A. Dunne, Richard J. Williams
Pacific Ecoinformatics and Computational Ecology Lab, Berkeley, California, USA
([email protected])
Synthesizing macroecology by scaling up species' modules into complex ecological networks
Scaling up small interaction modules of a few species into large complex networks of tens or hundreds
of species involves the synthesis of three major macroecological themes: species-area scaling, bodysize scaling, and food-web scaling. This integration is a type of meta-scaling that more
comprehensively addresses ecological systems by not only incorporating the biological scaling found
in separate macroecologcial perspectives, but also by synthesizing these perspectives to develop a
more general, unified ecological theory, which leads to a broader array of potential applications. In
our formulation, this integration results in surprisingly realistic models that can illuminate the
consequences of 1) embedding small modules of few species in large networks of many species, 2)
biodiversity loss of species including keystones, upper trophic level taxa, and apparently
“unimportant” species, 3) environmental variability, for example as expressed in nutrient supply, and
4) "devious" stabilizing strategies such as non-random food-web structure, nonlinear functional
responses, and the distribution of metabolic rates associated with consumer-resource body-size ratios.
Other achievements of this network centric approach include extending species-area relationships to
complexity-area relationships and extending contemporary studies of network structure back into deep
time to study how ecosystem structure has evolved over hundreds of millions of years. Future work
includes explanations of relative diversity and abundance based on body size and the quantity and
sharing of trophic resources, such that small consumers diversify by finely divide resources while
diversification of large consumers is constrained by being forced to share resources. This broad and
integrative research demands new information technologies currently being developed by the authors.
Beáta Oborny, Géza Meszéna and György Szabó
Department of Plant Taxonomy & Ecology, Lorand Eotvos University, Budapest, Hungary
([email protected])
Down the scales to the threshold - power laws in population extinctions
A simple spatial extension of the logistic equation of population growth suggests that extinction in
dispersal-limited populations is essentially a threshold-like process that is analogous to a critical phase
transition. We use this analogy to find robust, common features in the dynamics of extinctions, and
suggest early warning signals which may indicate that a population is endangered. As the critical
threshold of extinction is approached, the population spontaneously fragments into discrete
subpopulations and, consequently, density regulation fails. The population size declines and its spatial
variance diverges according to scaling laws. Therefore, we can make robust predictions exactly in the
range where prognosis is vital, on the verge of extinction.
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Michael W. Palmer
Botany Dept. Oklahoma State University, Stillwater, USA ([email protected])
Species-area curves and the geometry of nature
It is widely appreciated that species distributions and biodiversity can be strongly related to
environmental factors. Likewise, it is recognized that increasing environmental heterogeneity with
area is one of the determinants of species-area relationships. However, few theoretical treatments of
species-area relationships specifically address how biodiversity's increase with scale should be related
to the geometry of the environment. I hypothesize that this geometry is the underlying reason for the
triphasic species-area curve. The ability to test such hypotheses is complicated by physiological
integration and by the rarefaction effect. A careful decomposition of the components of scale may
help us understand the many different kinds of species-area curves we observe.
Joshua B. Plotkin
Harvard Society of Fellows, USA ([email protected])
Conspecific clustering and plant diversity in tropical forests
The relationship between sampled area and species diversity is fundamental to ecological theory, and
to conservation practice. I will discuss the observed scaling laws of plant diversity in tropical forests
censuses around the globe. Tropical forests exhibit non power-law scaling behavior which is
nevertheless replicable from site to site. Conspecific aggregation is pronounced for almost all tree
species, and it results in significant departures from Poisson random species-area curves. I will
discuss methods to characterize and estimate spatial clustering, as well as techniques to deduce the
demographic causes of aggregation in tropical forests. Information on conspecific clustering may be
combined with the distribution of species relative abundances to predict the species-area curve and its
sampling properties.
Mark Ritchie
Biological Research Laboratory, Department of Biology, Syracuse University, USA
([email protected])
Scaling of mechanisms that control diversity
Diversity measures and patterns are inherently scale-dependent, that is, one cannot specify a diversity
measurement or pattern without also specifying its scale. Many of the controversies over diversity
patterns, and thus hypotheses about what controls diversity, arise because the patterns compare
different-sized organisms samples at different spatial scales over different spatial extents. Using a
model of species coexistence through differentiation in resource use and in the scale at which different
species sample space, I show how resource partitioning, competition, and species interactions are
dominant mechanisms generating diversity at small scales of observation (extent), while
environmental capacity, colonization and local extinction processes are dominant mechanisms at large
spatial extents. Many well-known diversity patterns are predicted to change in their shape strictly as a
consequence of increasing the spatial extent relative to the sampling scales of organisms. Guilds or
communities of organisms that differ greatly in size and mobility (birds vs. plants) can therefore
exhibit different diversity patterns when examined at the same spatial extent. These model predictions
are tested and seem to explain differences in diversity patterns of different taxa, including plants,
grasshoppers, dung beetles, large mammals, and freshwater fish.
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Arnost L. Sizling
Center for Theoretical Study, Charles University, Czech Republic ([email protected])
Random clustering, scale invariance and abundances
Spatial biodiversity patterns are related to the patterns of species abundance and spatial distribution.
Current models show that species spatial aggregation is responsible for the exact properties of
biodiversity patterns, and that this aggregation can be depicted using the assumption of self-similarity.
However, there is no convincing universal theory that could explain why the spatial distributions
should be self-similar. We have developed a theory which predicts both species spatial distribution and
their abundance distribution in terms of random processes acting on various spatial scales. Several
geometric representations of theirs yield a lognormal-like species abundance distribution and the
spatial distribution revealing scale-invariance. Although this spatial distribution is not exactly selfsimilar, it has particular properties that make discerning it from true self-similarity almost impossible.
This new type of scale invariance seems to be more realistic and biologically plausible than the
classical fractal distribution, and might be generated by random processes of colonization and
extinction.
David Storch
Center for Theoretical Study, Charles University, Czech Republic ([email protected])
The species-area-energy relationship
Area and available energy (productivity) are major correlates of species richness. Little is known,
however, about the interaction between area and energy in determining species richness and
distribution. Using large-scale bird data sets from several continents, I will show that there is a
negative interaction between area and energy, i.e. the species-area relationship has lower slope in more
productive areas and the species-energy relationship is consequently steeper for smaller areas. This is
in accord with our previous finding that the slope of the species-area relationship depends on mean
species occupancy, and that species´ occupancies increase with productivity. The species-area-energy
relationship can thus be interpreted in terms of a general probabilistic model where both area and
productivity increase the probability that a site will be occupied by a species. On the other hand, there
is an evidence that the increase of occupancy with productivity is not followed by an increase of local
densities, and that local abundances are more even in more productive areas. I will provide a
simplified neutral model in an attempt to explain all these patterns within one framework.
Ethan White
Department of Biology, University of New Mexico, USA ([email protected])
Spatiotemporal scaling of species richness: a scaling approach to dynamic ecological systems
Abstract - The species-time relationship (STR) describes how the species richness of a community
increases with the time span over which the community is observed. This pattern has numerous
implications for both basic and applied ecology in much the same way as has already been recognized
for the species-area relationship (SAR). However, the STR has received significantly less attention and
to date only a limited number of studies have been published on the pattern. It is also becoming clear
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that these two patterns (the SAR and the STR) are not independent of one another, but that the scaling
of species richness in space affects the scaling in time such that at large time scales the exponents of
power law SARs are reduced and at large spatial scales the exponents of STRs are reduced. Here I
review and synthesize the work done on this subject to date, discuss it’s strengths and limitations, and
address challenges to, and opportunities for, the use of spatiotemporal scaling for understanding the
dynamics of ecological systems.
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