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Prairie Peninsula
(Area - 20,536,571 ha)
Executive Summary |
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Location and physiography - The Prairie Peninsula stretches
from northeastern Missouri, across much of Illinois and through the middle of Indiana into Ohio.
It is a gently rolling glacial plain in the west, but becomes flatter to the east, where prairie and oak
openings were embedded in beech-maple forest. Tallgrass prairie, savannah, and forest habitats
were interspersed throughout the Prairie Peninsula, although the percentage of prairie declined
from west to east. Savannah occurred in transition zones between grasslands and forest, although
the extent of savannah varied temporally and spatially with climatic conditions and other
ecological influences. Vegetation patterns were influenced primarily by fire, many of which in
recent centuries apparently were set by Amerindians.
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Priority
Bird Populations and Habitats
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Grasslands |
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![PIF](Pif_sm.JPG) |
Greater Prairie-Chicken
(27, AI=2, PT=3,
TB=4; % population - <1) |
This bird formerly was common in this physiographic area but
is now extirpated in Ohio and Indiana. It occurs in low numbers in Illinois and Missouri, and is
subject to the negative biological effects linked to small isolated populations. Loss of grassland
acreage as well as fragmentation and deterioration of grassland landscapes are to blame.
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![PIF](Pif_sm.JPG) |
Henslow's Sparrow
(26, AI=3, PT=3,
TB=4; % population - 4.4) |
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![PIF](Pif_sm.JPG) |
Dickcissel
(24, AI=4, PT=5,
TB=4; % population - 5.9) |
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Shurbland |
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![PIF](Pif_sm.JPG) |
Bell's Vireo
(23, AI=2, PT=3,
TB=4; % population - 2.9) |
Percentage is for eastern subspecies. |
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Wetlands |
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![PIF](Pif_sm.JPG) |
Black Rail
(26, AI=3, PT=3,
TB=4; % population - ?) |
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Deciduous forest |
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![PIF](Pif_sm.JPG) |
Cerulean Warbler
(25, AI=2, PT=3,
TB=4; % population - <1) |
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![PIF](Pif_sm.JPG) |
Red-headed Woodpecker
(23, AI=5, PT=5,
TB=3; % population - 10.9) |
This is one of the most conspicuous avifaunal elements of the
savanna habitat that has all but disappeared from this area. |
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![PIF](Pif_sm.JPG) |
Eastern Wood-Pewee
(20, AI=3, PT=5,
TB=3; % population - 3.2) |
All forest birds presumably underwent their greatest declines
here well before the BBS began. Populations appear to be low and studies show that
reproductive success is below that needed to sustain populations. The appearance of stability
results from immigration of birds from source populations in more heavily forested physiographic
areas. |
Complete
Physiographic Area Priority Scores (Zipped, Dbase5 file 288K)
Key to Abbreviations: AI-Area Importance, PT-Population Trend, TB-Threats to Breeding.
Priority Setting Process: General /
Detailed |
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Conservation issues and recommendations - Soon after European settlement,
the vast majority of grassland, savannah, and forest were converted to pasture, hayfield, and
cropland. Some agricultural habitats served as surrogate grasslands, contributing to range
expansion by a few species such as the Dickcissel and Horned Lark. Over the past 30 years,
however, these and other grassland birds have declined as the amount of land in pasture
decreased, and hayfields shifted to earlier maturing forage crops. Birds that nest in crops
harvested during the breeding season suffer an almost absolute loss of eggs and nestlings. It may
be impossible to recoup losses from conversion to more extensive and cleaner agriculture in
recent decades, but PIF encourages maintenance or restoration of high quality grassland habitat in
patches of sufficient size to support viable populations of high priority species.
Remaining forest habitat generally exists as small blocks in which nesting individuals
typically have low rates of nest success. Nevertheless, individuals in these areas may produce
some offspring and small patches can provide habitat for in-transit migrants. PIF recommends
retaining and, where possible, expanding these patches to sizes at which brood parasitism and
predation rates are significantly decreased.
Areas of savannah, also badly degraded, are optimal for some species such as the Red-
headed Woodpecker. Savannah restoration and management can provide significant benefits to
some birds, even in moderate-sized patches (up to 800 ha).
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