A new model
that can accurately identify stream sections that still hold suitable habitat
for wild brook trout will help US fisheries managers from Maine to Georgia find
and protect habitat for this fish, which is an economically, socially and
ecologically important species, Science Daily reports.
Developed by
researchers in Penn State's College of Agricultural Sciences, the model is
important because populations of native brook trout, Salvelinus fontinalis, declined precipitously throughout the fish's
native range in the eastern United States. Brook trout have been eradicated
from nearly a third of their historic watersheds and their populations have
declined by more than half in an additional third of watersheds in their range,
primarily because of habitat changes resulting from human land-use activities.
More than most
other fish in this country, wild brook trout need clean, cold water to survive,
according to Tyler Wagner, adjunct associate professor of fisheries, who is
assistant leader of the Pennsylvania Cooperative Fish and Wildlife Research
Unit at Penn State. However, centuries of agriculture, timbering and mining
resulted in siltation, sedimentation, contamination and higher stream
temperatures that doomed the fish in many of their native streams.
"Wild
brook trout have relatively narrow habitat requirements, but they were
historically widespread in areas where cold water, access to suitable spawning
substrates and instream cover were available," he said.
"However,
due to habitat loss, many populations are isolated and restricted to headwater
stream systems."
The model -
developed by Jefferson DeWeber, recent Ph.D. in Wildlife and Fisheries Science
now a postdoctoral scholar at Oregon State University - is described this month
in the Transactions of the American
Fisheries Society. This brook trout model builds upon a regional
river-water temperature model published by DeWeber and Wagner earlier this year
in the Journal of Hydrology.
Using
observations from more than 9000 stream sections with brook trout data, it
predicts brook trout occurrence using characteristics such as water
temperature, soils, and surrounding agriculture and developed land use.
Accuracy-tested by the researchers on more than 1800 stream sections, it can
predict brook trout presence in the approximately 240,000 stream reaches in the
historic brook trout range.
"The
fisheries research information incorporated in the model was compiled from data
collected by state fisheries management agencies across the brook trout range,
and we linked it to a giant GIS map of streams from Maine to Georgia,"
Wagner explained.
"Our model
provides a further understanding of how brook trout populations are shaped by
habitat characteristics in the region and yields maps of stream-reach-scale
predictions, which together can be used to support ongoing conservation and
management efforts. These decision- support tools can be used to identify the
extent of potentially suitable habitat, estimate historic habitat losses and
prioritise conservation efforts by selecting suitable stream reaches for a
given action."
Read the article HERE.
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