Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Roosa, Dean M.; Farrar, Donald R.; and Ackelson, Mark 1986 "Preserving Natural Diversity in
Trang 1Volume 93 Number Article 9
1986
Preserving Natural Diversity in Iowa's Loess Hills: Challenges and Opportunities
Dean M Roosa
Donald R Farrar
Iowa State University
Mark Ackelson
Iowa Natural Heritage Foundation
Let us know how access to this document benefits you
Copyright ©1986 Iowa Academy of Science, Inc
Follow this and additional works at: https://scholarworks.uni.edu/pias
Recommended Citation
Roosa, Dean M.; Farrar, Donald R.; and Ackelson, Mark (1986) "Preserving Natural Diversity in Iowa's Loess Hills: Challenges and Opportunities," Proceedings of the Iowa Academy of Science, 93(3), 163-165
Available at: https://scholarworks.uni.edu/pias/vol93/iss3/9
This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks For more information, please contact scholarworks@uni.edu
Trang 2Proc Iowa Acad Sci 93(3): 163-165, 1986
Preserving Natural Diversity in Iowa's Loess Hills:
Challenges and Opportunities
DEAN M ROOSA1, DONALD R FARRAR2 , and MARK ACKELSON3
The Loess Hills of western Iowa, due to their extent and depth, are of national importance for geological reasons They also harbor a large
portion of Iowa's remaining biological diversity, the significance of which has been underscored by studies sponsored by the State
Preserves Advisory Board during the past several years A complex of rare species of plants and animals exist in the rugged terrain; many
are Great Plains species which find their only Iowa stations in these Loess Hills Management problems, such as rapid invasion of prairies
by woody species, are manifest in this landform and must be addressed in the near future Land protection measures are being addressed
by the Department of National Resources, State Preserves Advisory Board, Iowa Natural Heritage Foundation, the Iowa Chapter of The
Nature Conservancy and County Conservation Boards The National Park Service has recently designated over 10,000 acres as a National
Natural Landmark
INDEX DESCRIPTORS: Loess Hills, Iowa's natural diversity, loess prairie, rare Iowa species
The geological significance of Iowa's Loess Hills has been realized
since the turn of the century (e.g Bain, 1896, 1898; Owen, 1905;
Shimek, 1896, 1907), and the biological significance has been known
for nearly as long (e.g Pammel, 1901; Shimek, 1908, 1910, 1911)
Because of a long hiatus in scientific studies in the Loess Hills, the
State Preserves Advisory Board, in 1980, funded a series of studies
designed to underscore the Hills' significance and to provide a basis
for preservation Results of these studies culminated in a symposium
on the Loess Hills presented at the 96th annual meeting of the Iowa
Academy of Science on April 17, 1984 Ten of the resulting papers,
surveying the biological diversity of the Loess Hills, were published in
the December, 1985 issue of the PROCEEDINGS The current issue
is devoted to the Geology, Paleontolgy, and cultural history of the
Hills
Given the world-wide significance of the loess deposits of western
Iowa, it is surprising that there has never been a concerted effort of
land protection in this landform region Only in recent years has
progress been made in recognizing the Hills' importance through
protection efforts
DISCUSSION Diversiry in the Loess Hills
Prairie
In the Loess Hills exists the majority of Iowa's remaining prairie,
with elements of the tall-grass and mixed-grass phases dominating
much of the rugged landscape The amount of prairie remaining has
not been precisely determined
Woodlands
As shown by original surveyor's notes, woodlands existed at the
time of settlement in the southern extreme of Iowa's Loess Hills and
along stream courses and sheltered slopes Since then, forest cover has
been increasing, providing an unusual opportunity to observe rates of
migration of woody species as well as of herbaceous understory plants
(Novacek et al 1985) Bur Oaks (Quercus macrocarpa) dominate the
forest community, with succession trending toward Basswood (Tilia
americana) on mesic slopes Black Maple (Acer nigrum) occurs in Holt
County, Missouri (Goodnight, 1964), providing an opportunity to
observe whether and at what rate this species will migrate northward
into Iowa
1 State Ecologist, Wallace State Office Building, Des Moines, IA 50319
2 Professor, Botany Department, Iowa State University, Ames, IA 50011 Trustee, Iowa
Chapter, The Nature Conservancy, 424 10th St., Des Moines, IA 50309
3 Associate Director, Iowa Natural Heritage Foundation, 505 Fifth Avenue, Suite 830,
Des Moines, IA 50309
Savannas
A few savannas remain intact in portions of the Loess Hills, particularly in the southern portion, representing the original transi-tion between the forested southern part and the open grasslands of the northern portion These are becoming invaded by woody shrubs and their integrity is rapidly being compromised
Rare species
A large number of species uncommon to Iowa have been docu-mented as occurring in the Loess Hills (see this issue and the December, 1985 issue of the PROCEEDINGS) Many of these are Great Plains species with an extension of their distribution reaching Iowa only in the Loess Hills (see for example, Novacek, 1985) A partial list of rare Loess Hills species follows:
Mammals
Grasshopper mouse Plains pocket mouse Southern bog lemming Cotton rat
Reptiles and amphibians
Great Plains skink Western spadefoot Great Plains toad Ornate box turtle Prairie rattlesnake
Butterflies
Ottoe skipper
Birds
Chuck-will's-widow
Plants
Prairie moonwort Tumble grass Sand lily Scarlet globe mallow Sensitive briar Missouri vetch Biscuit root Cobaea penstemon Montaine sedge
( Onychomys leucogaster) ( Perognathus flavescens) (Synaptomys cooperi) (Sigmadon hispidus) ( Eumeces obsoletus) (Scaphiopus bombifrons) ( Bufo cognatus) (Terrepena ornata) ( C rota/is viridis) (Hesperia ottoe) ( Caprimulgus carolinensis) (Botrychium campestre) ( Schedonnardus paniculatus) ( Mentzelia decapetela) ( Sphaeralcea coccinea) (Schrankia nuitallii) ( Astragalus missouriensis) ( Lomatium foeniculaceum) (Penstemrm cobaea) ( Carex saximontana)
There is a need to locate and protect the best populations of rare Loess Hills species Such protection could come from a variety of strategies including registry through The Nature Conservancy and acquisition by or easement with governmental agencies or private, non-profit organizations such as The Iowa Natural Heritage Founda-tion and The Nature Conservancy The highest degree of protecFounda-tion is preserve dedication through the State Preserves Advisory Board
Trang 3164 PROC IOWA ACAD SCI 93(1986)
Documentation of known sites of native Loess Hills biota and
discovery of new sites is occurring through natural history surveys,
and activities of the Iowa Natural Areas Inventory and the various
County Conservation Boards
Management considerations
A multi-faceted approach is needed for protection of sensitive Loess
Hills species Certain species require large, unbroken tracts for
long-term existence (Howe et al., 1985; Sampson, 1983) Through efforts
of the Department of Natural Resources and the Iowa Chapter of The
Nature Conservancy, some large tracts have been acquired The State
oflowa owns a 2724 acre ( 1102 ha) tract (Loess Hills Wildlife Area) in
Monona County, a tract of 1209 acres ( 489 ha) in the southern portion
(Waubonsie State Park) and 865 acres (350 ha) (Stone State Park) in
the northern part The Nature Conservancy, in cooperation with the
State of Iowa and the Plymouth County Conservation Board, recently
purchased a 792 acre (321 ha) tract (repurchased by the Plymouth
CCB in June, 1986) in the extreme northern portion (Five Ridge
Prairie, Plymouth County) Advantages of large-tract ownership are
(a) relative ease with which certain management methods can be
applied (e.g controlled prairie burns for community management)
(b) efficacy of re-introduction attempts for extirpated species (e.g
Prairie Chickens) (c) ease of law enforcement, and (d) ease of
popula-tion or community monitoring
A strong argument can also be forwarded for protection of small
areas which may contain a single species or community-type It is
probably more feasible, and certainly more cost-effective, to protect
some species, particularly microtines and plants, by acquisition of
small areas of suitable habitat This approach also appeals to many
landowners who retain only small tracts of native habitat due to
agricultural land-use However, relatively little is known about size
versus community stability (i.e how large a community must be to
survive over hundreds of years) or populaton size versus stability (e.g
how long a small population of a microtine may survive without
infusion of new genetic material from outside populations)
Both of these two approaches must be used for some species For
example, with migrating birds, the large areas are needed to provide
safe stopover sites, but it is the smaller areas which provide a
"corridor" for the species' movements The Loess Hills provide an
important opportunity for phytogeographical analysis (Novacek,
1985), and if further migration of vascular plants is to occur, there
must also be a sufficient corridor of protected native habitats There is
a basic framework for such a matrix of large areas connected by smaller
areas in the Loess Hills (Fig 1), but it is probably not yet sufficient for
long-term biological stability
Equally as important as acquisition of adequate land for
preserva-tion of biotic diversity is proper management of these acquisipreserva-tions In
addition, private landowners need assistance in good management
practices The Loess Hills Landform was historically nearly treeless,
except for the extreme southern part This was probably due to a
combination of fires and exposure of slopes to sun and drying winds
Since settlement, woody vegetation has increased dramatically, with
shrubs such as rough-leaved dogwood (Cornus drummondii), smooth
sumac (Rhus glabra) and various tree species invading the prairies It
has been estimated (Heineman, 1982) that this invasion by woody
species, if allowed to proceed at the present rate, will result in the bluff
prairies being converted to successional woodlands in 80 years, at least
in the central portion (Monona county) of the Loess Hills To maintain
the prairie areas, a more aggressive use of controlled burns or other
control measures is indicated
Land protection in the Loess Hills: present status, ongoing
projects and potential for the future
In the 1050 square miles (2720 km2) (672,000 acres) of what is
called the Loess Hills Landform Region (see Figs 1, 2, Farrar et al.,
1985) about 5500 acres (2226 ha) are owned by the State of Iowa and under the jur"sdiction of the Department of Natural Resources, about
2100 acres (850 ha) are owned by the County Conservation Boards of the seven western counties, about 150 acres (61 ha) are owned by The Nature Conservancy, and about 700 acres (284 ha) are owned by the municipalities of Council Bluffs and Sioux City (Fig 1)
National Natural Landmark
Periodically the National Park Service has shown interest in designating part of the Loess Hills as a National Natural Landmark in recognition of their national significance Following recommenda-tions of an evaluation report (Szymkowicz and Ruhe, 1981), the National Park Service recently designated 10,420 acres (4217 ha) as a National Landmark (see Federal Register for May 3, 1984 for notice) The area exists in two tracts, one north of Turin in Monona County; the other near Little Sioux in Harrison County While this confers no legal protection, it will make clear the fact that the Loess Hills are a nationally prominent feature Formal dedication as a National Natu-ral Landmark occurred on August 11, 1986
Loess Hills Pioneer State Forest
The Department of Natural Resources has recently approved a plan
to establish an approximate 17 ,000 acre (6800 ha) "Pioneer State Forest" in southern Monona and Harrison Counties This complex will exist in four tracts The first acquisition occurred in August,
1986 If completed and properly managed, these tracts may provide protection for certain sensitive species which require fairly large, unbroken segments of habitat for prolonged survival
State Preserve Designation
Formal dedication of an area as a State Preserve, which requires approval of the landowner and the State Preserves Advisory Board, and the signature of the Governor of Iowa, confers to the area a special form of protection As described in Chapter 11 lB, Code of Iowa, areas
so designated are protected against intrusion, inappropriate land-use,
or condemnation, and have the highest form of protection available under Iowa law To date, two areas in the Loess Hills have been so dedicated: the Five Ridge Prairie, purchased by the Nature Conser-vancy and now owned by the Plymouth County Conservation Board; and the Turin Loess Hills Preserve, owned by the State of Iowa and located in Monona County Agencies, organizations, municipalities, and private landowners should be encouraged to apply for this special form of protection if the holding is of sufficient quality to warrant preserve designation Archaeological, geological, and historical, as well as natural areas are considered for dedication by the State Preserves Advisory Board
Educational programs
Each year, a "Loess Hills Seminar" is conducted at the Loess Hills Wildlife Area near Onawa in Monona County Sponsored by the Western Hills Education Agency and area conservation organizations, this event is designed to increase the understanding and awareness of the geology, communities, and species of the Loess Hills School groups and other organized groups also gather periodically at Camp Angel, a 500 acre (202 ha) area managed by the Pottawattamie Counry Conservation Board, and located near Crescent, to learn more about the environment, particularly the Loess Hills
The Iowa Natural Heritage Foundation has recently commissioned
a traveling photographic exhibit entitled "Iowa's Loess Hills" The exhibit, with photographs by Don Pogensee of Ida Grove, brings to life the environment and spirit of this unique area and will be on display throughout Iowa in libraries, galleries, bar\ks, and other public buildings
Trang 4PRESERVING NATURAL DIVERSI1Y 165
CONCLUSIONS
We have a large responsibility in the Loess Hills; the programs
initiated will have an influence on all present and future Iowans All
Iowans should join in the effort to preserve the natural diversiry of the
Loess Hills, thus preserving a window through which we and future
generations can view the influence this great landform has had and
continues to have on the species inhabiting its wind-blown slopes
For more information about the Loess Hills, land protection
techniques, or educational programs, individuals may contact their
local County Conservation Board, the Department of Natural
Re-sources (Wallace State Office Building, Des Moines), State Preserves
Advisory Board (Wallace State Office Building), Iowa Natural
Heri-tage Foundation (505 Fifth Ave Suite 830, Des Moines), or The
Nature Conservancy (424 10th St., Des Moines)
LITERATURE CITED
BAIN, H.F 1896 Geology ofW oodbury County Survey Ann Rept 5
:241-299
BAIN, H.F 1898 Geology of Plymouth County Iowa Survey Ann Rept
8:315-366
FARRAR, D.R., D.M ROOSA and] C PRIOR 1985 Iowa'sLoessHills
- A national treasure Proc Iowa Acad Sci 92:157-158
GOODNIGHT, L.M 1964 Flora of Holt County, Missouri M.S Thesis,
University of Missouri, Kansas City
HEINEMAN, P.L 1982 Woody plant invasion of Iowa Loess Bluff prairies
Master's thesis, Univ of Nebraska, Omaha
HOWE, R.W., D.M ROOSA, J.P SCHAUFENBUEL, and W.R
SIL-COCK 1985 The distribution and abundance of birds in the Loess Hills
of western Iowa Proc Iowa Acad Sci 92: 164-175
NOVACEK, ] 1985 The Loess Hills of western Iowa: a problem in
phytogeography Proc Iowa Acad Sci 92:213-219
NOVACEK, J.M., D.M ROOSA, and W.P PUSATERI 1985 The
vegetation of the Loess Hills landform along the Missouri River Proc
Iowa Acad Sci 92: 199-212
OWEN, L.A 1905 Evidence on the deposition ofLoess Am Geo!
35:291-300
PAMMEL, L.H 1901 Preliminary notes on the flora of western Iowa Proc
Iowa Acad Sci 3:106-135
SAMPSON, F.B 1983 Minimum viable populations - a review Nat Areas
] 3: 15-23
SHIMEK, B 1896 A theory of the loess Proc Iowa Acad Sci 3:82-89
SHIMEK, B 1907 The loess of the Missouri River Proc Iowa Acad Sci
14:237-256
Fig 1 Parks, preserves and natural areas in the Loess Hills Landform
Region currently held by the state, counties, and municipalities, and by
The Nature Conservancy (DNR =Department of Natural Resources;
CCB=county conservation board; TNC=The Nature Conservancy)
1 Five Ridge Prairie 792 acres CCB
4 Sioux City Parks - 500 City
7 Schoenjahn Wildlife Preserve 126 CCB
9 Loess Hill Wildlife Area 2724 DNR
10 Turin Loess Hills Preserve 220 DNR
13 Loess Hills Pioneer Forest 17190 (proposed) DNR
14 Gleason-Hubel Wildlife Area 165 CCB,
15 Sawmill Hollow Wildlife Area 155 CCB
16 Smith Wildlife Area 201 DNR
17 Council Bluffs City Parks - 200 City
20 Waubonsie State Park 1209 DNR
SHIMEK, B 1908 The genesis of loess a problem in plant ecology Proc Iowa Acad Sci 15:57-75
SHIMEK, B 1910 Botany report, In: Geology of Harrison and Monona
Counties Iowa Geo! Survey Ann Rept 20:271-485
SHIMEK, B 191 L The Prairies Bull Lab Nat Hist Univ Iowa 6(2): 169-240
S2YMKOWICZ, M.T and R.V RUHE 1981 A survey of potential natural landmarks, geological themes, western central lowlands Natior'ia! Park System, Washington, D.C
(
,;
J
I ' ) ,)
\
( )
Plymouth
Woodbury
Pottawattamie
Mi I ls
(' Fremont
I ,)
\ ,
\
fl -1 ,,
-_.,,_J
~
' l
Trang 5Yucca, typically a western species, graces Iowa's Loess Hills Photo by Carl Kurtz