Last updated:
October 11, 2002
|
The Cape Sable Seaside Sparrow: why does a tiny bird have a large
impact?
Part 2: Scientists Analyze the Problem of How to Preserve a
Disappearing Species
Biologists monitor the sparrow population...
...and correlate habitat
condition with the health of the species.
|
25% of the sparrow's marl prairie
habitat has been lost to agriculture and urban development.
|
25% more habitat has been rendered
unsuitable due to changes in the dominant vegetation initiated by changes
in the hydrologic regime
|
|
|
|
Excessive and untimely flooding interrupt
sparrow nesting and lead to unsuccessful breeding seasons.
|
Restricted surface water inputs and
overdrainage result in the invasion of woody plants and a higher
incidence of fires.
|
|
|
By performing field surveys scientists
can closely watch the condition of the sparrow population
|
Cape Sable Seaside Sparrow Populations
with No Action
|
(Click on graph for larger version.)
With model simulations scientists
can predict potential outcomes for the species based on a variety of management
alternatives.
|
|
The continuation of research is critical
to the preservation of the sparrow at a time
when the population continues to decrease
under the current management system.
|
How to Preserve a Disappearing Species
Hydrologists Compare Past and Present Conditions
to Determine the Effects of Water Management Operations on the Sparrow
Habitat
|
Historically, water flow down Shark
Slough was evenly distributed over a wide area.
|
Today, canals and levees have forced
the flow westward constraining the waters to the west side of the slough.
|
|
|
|
| Northeast Shark Slough receives
little or no water from the conservation areas while canals east of the
Everglades lower water levels to provide flood protection. Overdrainage
of the Eastern population's habitat has resulted in an invasion of hardwood
vegetation and has left the area susceptible to frequent and severe fires. |
|
|
Western Shark Slough,
which historically received less than half of the total flow, is now flooded
with almost all of the water releases from the conservation areas.
Water is confined to the west side by the L67 extension canal and forced
onto the Western population of the sparrow.
|
|
|
The most significant factor in the
decline of the Cape Sable Seaside Sparrow is the redirection of the water
flows away from the Eastern population and towards the Western population.
|
Next: Scientists make recommendations for the
preservation of the Cape Sable Seaside Sparrow
|
