ARC Discovery Grant
Resource patchiness, dispersal and species co-occurrence: an experimental and
levels-of-evidence approach in some lowland streams
Summary of Proposal
A plain language summary of the aims, significance and expected
outcomes (approx. 100 words).
A central question in ecology is to understand what drives species cooccurrence patterns in spatially heterogeneous landscapes. A central
hypothesis is that the density and dispersion of resources of food and
living space interact with differing dispersal abilities of species to set
species’ distributions across localities. We will use some innovative
spatial analyses to devise a novel field experiment to test these
hypotheses, and a new levels-of-evidence procedure to evaluate
aspects that cannot be tested experimentally. We expect to show that
natural patchiness of resources is critical to understanding what drives
species co-occurrence patterns in nature.
Summary of National/Community Benefit (for publicity purposes)
A plain language summary of the national/community benefits
expected to arise from this research (approx. 100 words).
Millions of dollars are being spent on rehabilitating river ecosystems
that have often been highly simplified by human activities. It is
important that such rehabilitation be well-grounded in sound ecological
knowledge. We will test how the availability of essential resources of
food and living space affect the identity and density of species present.
We expect to provide practical advice allowing managers to enhance
biodiversity in streams surrounded by, and serving, agricultural areas.
Likewise, we will be able to advise on the consequences of excessive
water extraction on the likely success of such rehabilitation in rivers
with highly variable flows.
Aims:
The general aim of this research is to test theories about what drives
species composition in local communities embedded in spatially
heterogeneous landscapes.
Aims
In this project, we will simultaneously evaluate the importance of all
three hypotheses (RCDH, DLH and PFH) in determining the species
composition of the macroinvertebrate communities of some lowland
streams. These streams are model systems in which we can conduct
resource patch experiments, making use of areas where resources
have been reduced. Dispersal into and out of localities can be
quantified, and we have developed the spatial tools necessary to
recreating natural arrays of resource patches within experiments. The
specific aims are: (1) adopting a spatially-explicit view of resources
within local communities and using a new method of spatial statistics,
to quantify the density and spatial pattern of natural resource patches
(leaf packs, wood) occurring in different physical environments
(upland to mid-sections) of replicate streams, (2) to evaluate the
dispersal abilities of selected, key taxa at both the juvenile (aquatic)
and adult (aerial) life history stages, and (3) combining the
information from the first two steps, to test directly the RCDH for
explaining differences in species composition while simultaneously
evaluating the DLH and PFH.
What were the selling points of this grant proposal?
 A project situated within modern theoretical ecology around a
really important question – in this case, the theory about what
maintains the coexistence of species in communities
 A clear explanation of the barriers to progress and how our
approach would overcome those barriers
 New ideas for designing experiments that provided a different
and innovative way of testing hypotheses in the field
 Novel forms of analysis that hadn’t been tried before with
these problems
 A complete research plan with study sites, hypotheses,
expected outcomes, experimental designs, and levels of
replication explained
 A research team of two people, both with international
expertise in the research area and with complementary skills.