Abstract ID
eflows26
Type
Oral
Theme
eflows
Full title
Pulses and linkages in coupled aquatic-terrestrial ecosystems
Abstract text
Most ecosystems exhibit distinct resource, heatflow and energy pulses, often occurring together but also
sometimes separated in time or space. These interacting pulses provide the “complex template― to which
organisms are adapted and by which ecosystem processes are controlled.The importance of resource pulses,
such as flooding or import of marine nutrients from salmon runs, has gained increased attention in recent
ecological literature. It has been hypothesized that resource pulses are transmitted faster through aquatic
ecosystems because of faster growth rates compared to terrestrial ecosystems, and the impact of resource pulses
persists longer in terrestrial ecosystems because generation times are typically longer. Floodplains are excellent
model ecosystems to study the interrelationship between pulses and linkages. For example, timing, intensity,
duration, and frequency of flood pulses strongly influence what processes will be activated and at what rates
they will proceed within the floodplain habitat complex. However, human modifications that truncate or amplify
theses pulses will have cascading effects on river-floodplain interactions by shifting the thresholds of
connectivity, resilience, or resistance - causing drastic regime shifts. For example, we expect that relatively
small changes in the frequency, duration, magnitude and timing of drying and rewetting can result in large shifts
in net ecosystem exchange. Hence the ecosystem may switch from a carbon sink to a carbon source, or may
shift from a storage area to a processing area (with fast transformation rates) over short time scales. Most
aquatic insects, as well as pondbreeding amphibians, have complex life cycles, with aquatic egg, larval, and
pupal stages and terrestrial adult stages; thereby connecting the aquatic with the terrestrial system. For example,
during mass emergence of aquatic insects (e.g. mayflies, midges) a substantial proportion of the total benthic
biomass is transferred to the terrestrial ecosystem with fundamental, and often contrasting, impacts on both the
donor and the recipient systems.
Submission date
2009-10-22
Keywords
floodplain, subsidies, airscape, linkages, pulses
Will be submitting paper?
No