HomeMy WebLinkAboutIA City NAI Final ReportCity of Iowa City
Natural Areas Inventory and Management Plan
January 2018
Submitted to:
The City of Iowa City, Iowa
Submitted by:
Applied Ecological Services, inc.
CITY OF IOWA CITY – NATURAL AREAS INVENTORY AND MANAGEMENT PLAN | i
City of Iowa City
Natural Areas Inventory and Management Plan
Table of Contents
Acknowledgments ......................................................................................................................................iv
Executive Summary.....................................................................................................................................1
1 Introduction .....................................................................................................................................4
1.1 Natural Resources and Their Importance .............................................................................................4
1.1.1 Ecosystem Services ......................................................................................................................5
1.2 Reasons for a Natural Areas Inventory and Management Plan ............................................................6
1.3 What is Ecological Restoration? ............................................................................................................6
1.4 Restoration and Management Stages and Approach ...........................................................................7
1.4.1 Restoration and Short-Term Management ..................................................................................7
1.4.2 Long-Term Management .............................................................................................................8
1.5 What Happens When Natural Resources Are Not Managed? ..............................................................8
2 Background, Vision, Principles & Goals ...........................................................................................9
2.1 Background ...........................................................................................................................................9
2.2 Vision Statement ...................................................................................................................................9
2.3 Planning Principles ................................................................................................................................9
2.4 Project Goals ........................................................................................................................................10
3 Data and Methods ............................................................................................................................12
3.1 Existing Data Review ............................................................................................................................12
3.2 Aerial Imagery ......................................................................................................................................12
3.3 Desktop Methods ................................................................................................................................15
3.4 Field Assessment Methods ..................................................................................................................15
4 City-Wide Ecological Conditions & Assessment ..............................................................................17
4.1 Regional Context ..................................................................................................................................17
4.2 Landforms, Soils and Water Features ..................................................................................................17
4.3 Land Cover and Vegetation ..................................................................................................................18
4.3.1 Natural Land Covers ...................................................................................................................21
4.3.2 Cultural Land Covers ..................................................................................................................43
4.4 Invasive Species ...................................................................................................................................47
4.5 Wildlife .................................................................................................................................................49
4.5.1 Species of Greatest Conservation Need .....................................................................................49
4.6 Rare Natural Features .........................................................................................................................50
4.6.1 Federally-Tracked Natural Features ............................................................................................50
4.6.2 State-Tracked Natural Features ..................................................................................................53
5 Ecological Restoration and Management Challenges and Considerations .................................55
5.1 Core Habitat, Edge Effects and Connections ........................................................................................55
5.2 Pests and Diseases ...............................................................................................................................57
5.3 Climate Change Implications for the City’s Natural Resources ............................................................57
6 Review of City Policies, Ordinances and STAR Goals ......................................................................59
6.1 STAR Community Rating System ..........................................................................................................59
6.2 Center for Watershed Protection Codes and Ordinance Worksheet...................................................59
7 Summary of Findings .......................................................................................................................61
7.1 Vegetation ............................................................................................................................................61
7.2 Wildlife .................................................................................................................................................61
7.3 Water and Hydrology ...........................................................................................................................61
CITY OF IOWA CITY – NATURAL AREAS INVENTORY AND MANAGEMENT PLAN | ii
8 Ecosystem Model for Restoration and Management ....................................................................62
8.1 What is an Ecosystem Model and Why is it Useful? ............................................................................62
8.2 Conditions of the Distant Past (before the early 1800s) ......................................................................62
8.3 Recent Historical and Present Conditions (early 1800s to 2017) .........................................................63
8.4 Anticipated Future Conditions (2050 Without and With Intervention) ...............................................64
8.4.1 Without Intervention .................................................................................................................64
8.4.2 With Intervention .......................................................................................................................64
9 Ecological Restoration and Management in Iowa City .................................................................65
9.1 Proposed Native Plant Communities ...................................................................................................65
9.2 Species-Specific Goals ..........................................................................................................................65
10 Restoration and Management Tasks ..............................................................................................66
10.1 Remove Invasive Woody Vegetation ..................................................................................................66
10.2 Control Invasive Herbaceous Vegetation ...........................................................................................66
10.3 Install Herbaceous Vegetation ...........................................................................................................67
10.4 Install Woody Vegetation ...................................................................................................................67
10.5 Ecological Monitoring ........................................................................................................................67
10.6 Prescribed Burning .............................................................................................................................67
10.7 Convert Turf to Native Vegetation .....................................................................................................68
10.8 Streambank and Ravine Stabilization .................................................................................................68
11 Opportunities for Improved Connectivity ......................................................................................70
11.1 Potential Natural Area Connections ...................................................................................................70
11.2 Potential Waterway Connections ......................................................................................................70
12 Monitoring, Adaptive Management and Training .........................................................................71
12.1 Ecological Monitoring and Adaptive Management ............................................................................71
12.2 Specialized Training ............................................................................................................................71
13 Use of Volunteers for Monitoring or Management .....................................................................72
14 Restoration and Management Prioritization, Phasing and Costs ................................................73
14.1 City-wide Restoration and Management Priorities and Costs ...........................................................73
14.2 Site-scale Restoration, Management Units, Phasing and Costs .........................................................73
15 Perpetual Management ....................................................................................................................74
15.1 Perpetual Management Tasks ............................................................................................................75
15.2 Perpetual Management Schedule......................................................................................................75
16 City Policy and Ordinance Recommendations ................................................................................76
16.1 Recommendations for Improving the STAR Rating ............................................................................76
16.1.1 Biodiversity and Invasive Species (NS-2) ...................................................................................76
16.1.2 Natural Resource Protection (NS-3) .........................................................................................78
16.2 Recommendations for Improving the Center for Watershed Protection Worksheet Score ..............79
16.2.1 Natural Area and Significant Tree Protection ...........................................................................80
16.2.2 Vegetation Management ..........................................................................................................81
16.2.3 Stream and Waterway Protection ............................................................................................81
17 Public Outreach & Interpretation ...................................................................................................83
17.1 Outreach Strategies ............................................................................................................................83
17.2 Interpretation Strategies ....................................................................................................................83
18 Staffing Recommendations and Funding Opportunities ................................................................84
18.1 Staffing Recommendations ................................................................................................................84
18.2 Funding Opportunities .......................................................................................................................84
19 Conclusion .......................................................................................................................................86
20 References & Resources Consulted ..................................................................................................87
CITY OF IOWA CITY – NATURAL AREAS INVENTORY AND MANAGEMENT PLAN | iii
Tables
Table 1. Land Cover Classification .......................................................................................................................19
Table 2. Iowa City Parks and Natural Areas Land Cover ......................................................................................20
Table 3. Invasive species in Johnson County and Iowa City, Iowa. ......................................................................48
Table 4. Summary of Habitat Preferences of Species of Greatest Conservation Need Statewide
by Habitat Class (Iowa DNR 2015) ..........................................................................................................50
Table 5. Federally-Listed Species Potentially Affected by Activities in Iowa City, Iowa. ......................................51
Table 6. High Quality Natural Communities in City Parks (adapted from Iowa DNR data) ..................................54
Table 7. Use of Volunteers for Different Management Tasks...............................................................................72
Table 8. Generalized Restoration and Management for a Given Project Area ....................................................74
Table 9. Generalized Ecological Restoration & Management Unit Costs .............................................................74
Table 10. Perpetual Management Schedule ........................................................................................................75
Figures
Figure 1. Flight plan for collecting Iowa City aerial imagery showing flight paths along which
photos were taken ...............................................................................................................................13
Figure 2. Landform regions of Iowa (Iowa DNR 2015). ........................................................................................17
Figure 3. Core (interior) habitats and edge habitats (Bentrup 2008) ..................................................................55
Figure 4. Edge effects from development and disturbance (Bentrup 2008). .....................................................56
Figure 5. Gradients of ecological connectivity (Bentrup 2008). ..........................................................................56
Exhibits
Exhibit 1. Regional Context ..................................................................................................................................89
Exhibit 2. Landforms, Soils and Water Features ...................................................................................................90
Exhibit 3. Existing Land Cover of Parks and Natural Areas ...................................................................................91
Exhibit 4. Natural Areas in and Adjacent to Iowa City ..........................................................................................92
Exhibit 5. Pre-1800 Vegetation .............................................................................................................................93
Exhibit 6. 1930s Aerial Photograph ......................................................................................................................94
Exhibit 7. 2015 Aerial Photograph ........................................................................................................................95
Exhibit 8. City Natural Areas and Connections .....................................................................................................96
Appendices
Appendix A. Glossary ..........................................................................................................................................98
Appendix B. Individual Site Management Briefs .................................................................................................99
Appendix C. Compiled Flora of Iowa City, including Invasive Species of Concern (in red) .................................444
Appendix D. Minnesota Department of Natural Resources Identification and Description of
Practices to Avoid the Introduction or Movement of Invasive Species ..........................................462
Appendix E. U.S. Fish and Wildlife Service Information for Planning and Consultation (IPaC)
Report for Iowa City .......................................................................................................................464
Appendix F. Iowa Natural Areas Inventory State-Listed Species in Johnson County (Iowa DNR 2017b) ............476
Appendix G. Center for Watershed Protection (CWP) Scorecard for Iowa City .................................................480
Appendix H. Native Species Lists for Ecological Restoration and Enhancement of Iowa City Natural Areas .....495
Appendix I. City-wide Prioritization, Phasing and Costs of Natural Resources Management ..........................502
CITY OF IOWA CITY – NATURAL AREAS INVENTORY AND MANAGEMENT PLAN | iv
Acknowledgments
Applied Ecological Services gratefully acknowledges City of Iowa City staff, which directed and contributed to
this Natural Areas Inventory and Management Plan. City of Iowa City contributors include:
Juli Seydell Johnson - Director of Parks & Recreation
Brenda Nations - Sustainability Coordinator
Zac Hall - Park Superintendent
Ben Clark - Senior Civil Engineer
Killian Laughead - Senior Engineering Technician
Amanda Opitz - Recreation Program Supervisor/Customer Engagement
Prepared for:
City of Iowa City
410 E. Washington Street
Iowa City, Iowa 52240
319-356-5000
Prepared by:
Applied Ecological Services, Inc.
21938 Mushtown Road
Prior Lake MN 55372
952-447-1919
AES project 16-0777
Kim Alan Chapman, PhD
Doug Mensing, MS
Benjamin Staehlin, MS
Susan Lehnhardt, BS, BA
Will Overbeck, MS
David Aslesen, BS
Citation: Applied Ecological Services. 2018. City of Iowa City Natural Areas Inventory and Management Plan.
Report for the City of Iowa City, IA.
EXECUTIVE SUMMARY | 1
Executive Summary
Iowa City was founded on the natural resources in and around the Iowa River and its tributaries. Early American
settlers recognized the value of the Iowa River for transportation and water power and the surrounding prairies
as highly productive cropland. Over the decades, the City developed an extensive park system for both active
and passive recreation. Iowa City has over 1,500 acres of parks and natural areas, harboring several high quality,
large ecosystems characteristic of central Iowa. Natural areas in the parks represent the City’s best and most
protected natural habitat. A natural area is land and water that exists in a natural condition, with human use
largely limited to foot traffic. Natural areas vary greatly in size, the type of vegetation they contain, and the
connections to other natural areas—connections that let many species survive in good numbers over time.
These parks and natural areas are valuable to the community, providing important ecosystem services—those
spontaneous benefits people gain from nature’s processes—such as water purification and regulation, soil
building and maintenance, wildlife and fish production, and air purification. On the other hand, past land uses,
erosion, and colonization by invasive species compromised the functions and value of the City’s natural areas
and natural resources. This plan seeks to reverse that trend and improve the ecological health and resilience of
the City (including meeting the City’s STAR Community goals) by laying out a program of ecological restoration
and management for the next ten years.
Iowa City’s park system contains about 430 acres of forest, 188 acres of prairie, and 79 acres of wetlands—as
well as smaller areas of savanna, shrubland, and open water. This land and water supports recreation, serves
stormwater management and wellhead protection, and achieves wetland mitigation. Iowa City is proud of its
recent progress in managing natural areas. The City has invested about $8 million dollars to purchase, construct,
and maintain these areas. Long-term planning, focused management, and additional funding are needed to
control invasive species, conduct prescribed burns, and implement conservation practices that protect this
investment and ensure the health and resilience of its natural areas for the long term. Only with a commitment
to ongoing and long-term management will the cultural, economic and ecological benefits and attractiveness of
these natural areas be ensured.
This Natural Areas Inventory and Management Plan (“Natural Areas Plan”) identifies locations owned or
managed by the City that warrant management. It also specifies how best to restore and regularly manage
these areas in order to preserve their ecological functions and increase biodiversity, which the STAR
Community guidance recommends. Without this planning, together with adequate funding and a program of
implementation, the City may not achieve its STAR goals for the environment and other conservation goals. A
glossary of technical terms is found in Appendix A.
This vision statement was developed specifically for Iowa City’s Natural Areas Plan.
Iowa City recognizes the important role that natural areas play in an urban and suburban setting. The City’s
natural areas are a boon for local residents, an enjoyable and interactive experience for families, children,
and visitors, an outdoor classroom for students of all ages, and a home for a surprising variety of wildlife.
Maintaining an equitable distribution of natural landscapes throughout the City ensures that current and
future generations will continue to enjoy these resources. These renewed spaces will persist in supporting a
strong and diverse economy, fostering healthy and active lifestyles, advancing environmental sustainability,
and enhancing quality of life.
These planning principles, developed by staff and consultants, will guide natural areas restoration and
management in Iowa City.
Overall
• Protect the City’s sensitive natural resources in order to foster resilient and biodiverse natural areas within Iowa
City
• Understand the historical and current conditions of natural areas to describe a future ecological path for natural
resources
• Design within the limits of existing soil, hydrology, and vegetation conditions
• Create attractive and resilient plant communities that can be managed economically
• Tell the ecological story of the City to inspire people through its restoration
• Bring people into the City’s natural areas while protecting biodiversity and ecosystem resilience
EXECUTIVE SUMMARY | 2
• Use indicators and monitoring to document trends in natural resources and determine the success of restoration
and management efforts
Vegetation
• Protect and restore the City’s rare ecological land cover types to prevent their disappearance
• Maintain and enhance common land cover types
• Promote a natural variety of native flowering plants across the growing season
• Control the invasive or aggressive native plants that reduce biodiversity and ecological resilience
• Establish a vegetation structure that requires the least effort to maintain
Wildlife
• Protect, improve, and restore habitat for all wildlife
• Create the largest, roundest habitats for area-sensitive wildlife species (round habitats tend to be higher quality
because they resist negative edge effects from adjacent land uses)
• Design to reduce wildlife-damaging edge effects from adjacent properties
• Install special habitat features (nest boxes, etc.)
• Identify and seek to make connections to similar habitat on nearby conservation lands
Soil & Hydrology
• Preserve stable soils and natural hydrology
• Find solutions to eroding soils and damaged hydrology
• Protect neighboring properties from water damage
• Use vegetative stabilization and a natural ecosystems approach before resorting to more hard-armored and
engineered solutions
• Use a series of natural features (e.g., rain gardens, prairies, wetlands) to manage stormwater runoff from
impervious cover, beginning with reducing runoff at its source
• Design soil and hydrology solutions in the most cost-effective way possible
Human Use
• Separate minimum use sensitive natural areas from locations that can accommodate higher use
• Make management easier by defining management units and access points
• Detect problems early by monitoring trail and off-trail use
• Recruit organizations, experts and volunteers to help maintain and monitor natural areas
• Protect cultural resources
This Natural Areas Plan focused on 42 City parks and natural areas selected by City staff and consultants.
Existing reports, plans, and other information were gathered and reviewed. At the project onset in 2016,
Applied Ecological Services, Inc. (AES) took high resolution, multi-spectral aerial imagery of the entire City. This
increased the efficiency and accuracy of land cover mapping of natural areas; the imagery will be useful for
other City purposes as well. With an intensive field effort in 2017, the consultants completed an inventory and
quality assessment of all sites. To broadly characterize each site, land cover was mapped and plant communities
documented in photos. Plant species were identified and given an abundance rating in each plant community at
each site. Incidental wildlife observations also were made.
The inventory and assessment confirmed that Iowa City supports regionally significant natural areas, uncommon
native plants, and interesting animal species. All of the 42 sites, however, were affected by past incompatible
land uses, invasive species, and suppression of surface fires, a natural disturbance that most of the City’s original
plant communities required on a regular basis to maintain their integrity.
EXECUTIVE SUMMARY | 3
The field of applied restoration ecology has developed techniques for addressing these issues and impacts.
Removing invasive vegetation, planting diverse native species, and restoring natural disturbances, especially
prescribed burning, are proven and effective ways to restore the ecological health of natural lands and waters.
Landscape ecology and population biology have demonstrated that enlarging and connecting natural areas
creates viable habitat for many species that disappear from small, isolated natural areas. Better quality and
larger, more connected natural areas will increase the enjoyment by residents and visitors of the natural bounty
and beauty in Iowa City’s parks.
Brief management plans for each of the 42 sites—called “management briefs”—provide guidance for Iowa
City staff, volunteers, and others to understand the restoration and management intentions for each site
(Appendix B). Each management brief gives general site information, detailed plant lists and abundance by plant
community, restoration and management recommendations, and opinions of probable cost to complete initial
restoration and management work.
Every City has competing financial priorities. Recognizing this, City staff and consultants developed a ten-year
site priority and phasing plan for restoration and management work. The scenario described in this Natural
Areas Plan assumes $100,000 is expended in the first year and slightly more for the following nine years,
increasing 2 percent annually for inflation. One quarter of the budget is assumed to come from grants, with
the City to provide $75,000 in its annual budget. Work begins with the largest, most important natural areas:
Ryerson’s Woods, Hickory Hill, Kickers Soccer Park, Sand Prairie, Sycamore Greenway, Terry Trueblood, and
Waterworks. The City can expand its effort to other areas with new funding sources, such as new REAP grants,
and cost-saving strategies including partnerships and volunteers. Funding staff positions dedicated to natural
area restoration and management can leverage additional restoration and management work by directing
volunteers, writing grants, and doing the work itself.
Executing this Natural Areas Plan and raising STAR scores for the environment will also require that the City
revise its policy and ordinances to benefit natural areas, rare species, and ecosystem health. Committing to
perpetual stewardship after the initial major restoration effort finishes is, of course, the most important first
step the City can take to improve the health and resilience of its natural areas and secure their ecosystem
services and recreational benefits for its residents.
INTRODUCTION | 4
1 Introduction
Iowa City’s park system contains approximately 430 acres of forest, 188 acres of prairie, and 79 acres of
wetlands – plus additional acres of savanna, shrublands, and open water. These natural areas provide a variety
of benefits, including recreation, stormwater management, wellhead protection, and wetland mitigation. Iowa
City is proud of the progress made in natural areas management over the past decade. The City has invested
approximately $8 million dollars to purchase, construct, and maintain these areas. Coordinated management,
long-term planning, and additional funding are necessary to control invasive species, conduct prescribed
burns, and implement other conservation practices to protect the City’s investments and ensure the health
and resilience of its natural areas over the long term. Ongoing management is essential to maintaining the
functional, economic, recreational, and aesthetic values of these natural areas. Qualified personnel are needed
to oversee this effort. These individuals have a deep understanding of ecology and ecosystem processes, and
extensive experience with prescribed burning and other management methods, invasive species identification
and control practices, and native plant, animal and soil identification.
While once abundant in Iowa, only a fraction remains of the original prairies, savannas, wet meadows, marshes,
woodlands and forests. Actions taken now to implement the long-term management of natural areas in Iowa
City not only secures these valuable resources for residents, but contributes to the protection and perpetuation
of Iowa’s natural heritage.
The purpose of this Natural Areas Inventory and Management Plan (“Natural Areas Plan”) is to identify locations
owned or managed by the City that warrant management, and specify how best to restore and regularly manage
these areas in order to preserve their ecological function and maintain or increase biodiversity. The urban and
suburban environment of many of the City’s natural areas poses a challenge that can nevertheless be overcome
with good planning and proper management. In this way the City’s residents will ensure that past investments
are protected and the future benefits of natural areas are secured.
1.1 Natural Resources and Their Importance
The American settlers who came to Iowa City in the mid-1800s recognized the importance of the Iowa River for
navigation and water power. Since that time the vast prairies on the surrounding high ground were converted to
productive cropland, while the steep blufflands and stream valleys were used for grazing and a source of wood.
The development of the city followed.
Today Iowa City has protected 1,500 acres of what remains. These natural resources existed spontaneously
before Americans arrived. Today we classify them as non-living (sunlight, air, water, metals, and minerals)
and living (soil, vegetation, and animals). Sunlight and air are abundant, while fresh water and certain animal
populations are not. Some, like endangered species, are quite rare. Although some natural resources are
thought to be inexhaustible, most are limited and can be lost if over-used or managed poorly.
Our society and other modern economies value natural resources for how useful they are (extrinsic value).
These include timber, gravel, cropland soils, groundwater, and surface water. Some people believe that all
species have a basic right to exist—they have intrinsic value. There is a large and growing body of ethical
thought which grants humans and nature equal standing. Aldo Leopold—born in Burlington, Iowa—was a
conservationist and the first professor of wildlife biology in the country. He promoted the idea of a land ethic,
in which people saw themselves as part of the ecology and responsible for treating it well. He wrote in his best
known book, A Sand County Almanac,:
A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is
wrong when it tends otherwise.
and
We abuse land because we regard it as a commodity belonging to us. When we see land as a community
to which we belong, we may begin to use it with love and respect.
The idea that nature has intrinsic value has been gaining support as people look for experiences in park natural
areas, through travel, by visiting museums and zoo exhibits, or simply watching television programs about
nature.
INTRODUCTION | 5
It is also well known that most people want to live near parks and open space. Homeowners and businesses
consistently rate proximity to a park as highly desirable, which typically generates higher demand for buildings
near open space. Several studies have measured the effect of parks on property values and found a value
increase. For example, a study from Michigan State University focused on Dallas, Texas, found that distance
to and size of a park resulted in a price premium of up to two to three percent. Other researchers found that
homes next to greenbelts in Austin, Texas saw an increase in value of six to twelve percent. In Minnesota’s Twin
Cities, researchers summarized four property value studies and found that proximity to parks increased urban
and suburban property values, except in suburbs where active recreational parks decreased property values.
1.1.1 Ecosystem Services
Besides the economic value of the land itself, natural areas are vital to Iowa City residents for several reasons.
Wetlands and forested areas along rivers and streams help reduce flood impacts, and prairies and forests absorb
rainfall, reducing the amount of runoff and eroded sediment reaching City waters. Natural areas also absorb
and store atmospheric carbon, helping the City’s efforts to reduce greenhouse gasses. Schools, organizations
and families use many natural areas to learn about the natural world in an outdoor setting, especially important
for young children who spend less and less time outdoors. The City’s quality of life is elevated by natural areas,
which give citizens and visitors nearby opportunities to walk, bike, bird watch, or to simply sit still surrounded by
greenery.
Iowa City residents may not realize that natural areas provide these benefits, called “ecosystem services”. These
services actually save people expenses over the long term (see the Millennium Ecosystem Assessment 2005). If
people were to pay to clean the air and water, to build soil or regenerate forest trees and wild fish and game, the
cost would be in the hundreds of millions of dollars annually for Johnson County alone. Building flood control
infrastructure, or rebuilding after floods, would be much more expensive without floodplains and the natural
capacity of watersheds to regulate the water moving through them.
Ecosystem services include:
Supporting (Natural Processes)Provisioning (Goods)
• Photosynthesis to grow plants • Clean air
• Nutrient cycling (carbon, phosphorus, etc.)• Fresh, clean water
• Carbon sequestration in plants & soil • Fertile & productive soil
• Soil formation • Food production
• Erosion control by vegetation and soil biota • Forest products (lumber, paper pulp, etc.)
• Air purification and oxygen production • Fuel production (biomass for energy)
• Water purification • Game & fish production
• Decomposition of waste • Biodiversity & wild genetic material
• Detoxification of soil & water
• Groundwater recharge Regulating
• Disease and pest control • Climate stabilization
• Pollination of crops and wild plants • Water volume and flow regulation
• Seed dispersal for regeneration • Flood and drought regulation
• Local shading and cooling (microclimate)• Disease and pest regulation
• Blocking of harmful ultraviolet radiation • Hazard reduction
People’s health and well-being benefit from natural resources, too. Research in the last twenty years has
demonstrated a strong link between time spent in or near nature and better physical and mental health.
Viewing nature out a window can improve test scores in school children or elevate moods in adults. Of course,
people love to fish, hike, bike, ski, picnic, camp, and celebrate with family in natural areas. Sometimes just sitting
still in nature can nourish the spirit and calm people.
INTRODUCTION | 6
Iowa City’s character also emerges from its natural resources. They create a sense of place that attracts people
and businesses and convinces them to remain in the area. They cause people to visit and spend time in Iowa
City, or convince people and business here to remain. Ecosystem services not only support and enrich society
and the economy, they are the foundation of a healthy environment. Ecosystem services can be conserved by
protecting and managing Iowa City’s natural areas.
1.2 Reasons for a Natural Areas Inventory and Management Plan
A story of loss is also a story of hope. It begins with recognizing that many of Iowa City’s natural resources have
been lost, fragmented and degraded over the past 150 years. Rejuvenating natural processes such as fire, which
shaped vegetation and wildlife for thousands of years, have been largely eliminated. Invasive species further
challenge the goal of maintaining healthy ecosystems and natural resources.
Nature has an amazing ability to recover from past injury and take care of itself in the long term. Some
landowners know that management is needed to prevent deterioration or improve the quality of natural
resources on their lands. Natural resource management is complicated and requires knowledge of ecological and
hydrological systems and cycles, of the ways that climate is shifting, and the habits of plants and animals. When
deciding how to manage natural resources, Iowa City should consider the following:
• Main purpose for protecting and using the land
• Current natural resource conditions
• Issues and concerns about the natural resources
• Adjacent land use that affects natural resources
• Government policies and ordinances
• Demographic changes that are affecting how natural resource are or could be used
• Existing and future financial resources for restoring and managing natural resources
Iowa City approved the development of this Natural Areas Plan in recognition of these factors and is committed
to improving natural resource management on City-owned lands. This report represents a system-wide plan for
natural areas that:
• Presents the results of a system-wide natural areas inventory;
• Describes in moderate detail the issues facing the City’s natural areas;
• Specifies the vision, principles and goals for managing these natural areas;
• Presents issues facing natural areas on system-wide and individual park basis;
• Specifies management approaches and priorities to strategically implement ecological restoration and
management throughout the City; and
• Provides a phasing plan and annual cost estimate for carrying out the first ten years of the plan.
This plan is a strong foundation for refining and expanding, if desired, natural resource management plans
for individual parks and natural areas. Natural resource management plans can use information from this
system plan as a framework to complete more detailed assessments, refine restoration and management
recommendations, and develop more accurate cost estimates for implementation. Implementation of this City-
wide plan and future detailed natural resource management plans will enhance biodiversity throughout the City,
enhance human enjoyment of natural areas, and put natural areas on a trajectory towards long-term ecological
health and resilience.
1.3 What is Ecological Restoration?
Iowa City has engaged in several ecological restoration projects, chiefly prairies and herbaceous wetlands.
Ecological restoration is the art and science of improving the health and resilience of natural environments
by stabilizing and enhancing diversity and natural processes. Scientific understanding of ecologically healthy
INTRODUCTION | 7
plant communities and ecosystems is used by restoration ecologists to describe current conditions and lay out
a program to effect positive changes. Species in decline or uncommon, species that need high quality or large
habitats, and species that respond poorly to intensive human use all benefit from this approach. Iowa’s Wildlife
Action Plan suggests that up to half of all species in some animal groups need active management to prevent
further declines. Moreover, people benefit from the improved functioning of ecosystems, from the large scale
to the personal. A glossary of technical terms is found in Appendix A.
1.4 Restoration and Management Stages and Approach
The focus of ecological restoration is to create healthy and sustainable ecosystems, often in the context of
a developed or disturbed landscape. The composition, structure, and function of restored ecosystems are
similar to that of native ecosystems. As a result, a moderate level of management is necessary to maintain
these ecosystems in perpetuity. Restored ecosystems are recognizable by a diversity of native plant and animal
species and an increase in functionality and resilience.
This plan will guide the restoration and management of plant communities native to the region. However,
changes in the larger landscape and in local conditions often prevent the full re-creation of natural conditions
from 150 years ago. Those historical conditions provide insight into what natural conditions are possible at a
given site, and no more. More importantly, the goals of a project area will dictate the level of effort expended
and the eventual condition of the ecosystems. Not all City natural areas will be restored to exceptional native
plant communities, but all will be restored and managed to meet City goals. As more healthy and sustainable
ecosystems are restored, ecological functioning, wildlife populations, and human enjoyment will be enhanced.
Restoration and management plans need to be flexible. Restoration programs experience variability in
implementation due to the timing of funding, adjustments due to the response of the ecosystems to restoration
work, and changing management needs. At times, programs need to respond to new scientific data and insights.
For these reasons, the restoration and management briefs included in this plan (Appendix B) should be viewed as
a starting point in a process of restoring the biodiversity and natural processes to the City’s natural areas. This
plan should guide major restoration and management efforts and projects. As more detailed data are gathered,
it is expected that restoration and management activities will be refined. The most successful restoration
programs use regular monitoring and reporting as feedback on the program’s effectiveness. Monitoring also
generates information to justify changes in the restoration and management program. Adaptive management
(a cycle of implementation, monitoring, evaluation, adjustment, and implementation) is central to the best
restoration programs and should begin with the initial restoration work and continue indefinitely as part of
the stewardship of the project area. Mutual benefit can be gained from engaging “citizen scientists” as well as
universities and schools to assist with observations, data collection, and analysis, whereby the site becomes
a “living lab” for research and study as well as public education and engagement. Some types of monitoring
require a higher level of expertise, training, or oversight.
1.4.1 Restoration and Short-Term Management
Ecological restoration has short- and long-term management phases. The initial short-term, or “establishment”
or “restoration” phase is the most time-consuming and costly. Usually lasting three to five years, a significant
effort is needed to prepare and begin establishing the proposed native plant diversity types and ages for
different management units. Tasks often include selective woody plant removal, controlling invasive species
with herbicide, soil preparation, seeding and planting native species, re-establishing natural hydrological cycles
in aquatic systems, re-introducing fire regimes in fire-dependent systems, and using bio-control techniques for
invasive species management when available. The length of time before moving from short-term to long-term
management depends on many factors including the site’s initial quality and other issues, weather conditions,
how the site responds, size, and other complexities of the area.
“Enhancement” is a management term used to describe activities where minimal-to-moderate effort and cost is
required to improve the resource. Adding more native flower species into a reconstructed prairie, or removing
box elder from an oak forest, or planting native shrubs are examples of enhancements.
INTRODUCTION | 8
1.4.2 Long-Term Management
After short-term restoration and management goals are achieved in a project area, the process shifts to a
lower-cost, but equally important, long-term (or perpetual) “maintenance regime.” Without a commitment
to long-term management, it is likely that short-term restoration investments will be wasted. Scheduling and
budgeting for long-term management each year will protect the investment already made, and ensure that
the plant community and wildlife continue on a trajectory toward greater ecological health. Typical long-term
management tasks include spot-herbiciding of invasive plants, re-seeding disturbed or poorly developing areas,
re-planting woody plants that have died, and maintaining appropriate ecosystem disturbances to perpetuate
a diverse and resilient plant community. Most ecosystems need some type of disturbance that removes dead
plant material, regenerates many plant species, and opens up new habitats for plants and animals to perpetuate
themselves or to maintain diversity. Controlled burns in fire-dependent communities (prairies, savannas,
wetlands, and some woodlands), which mimic wildfire, are a common tool to achieve this objective. Harvesting
hay from prairies, which mimics grazing, can also be effective. One-hundred fifty years ago, the vast majority of
Iowa City was frequented by fires, and the plants and animals were adapted to those conditions.
1.5 What Happens When Natural Resources Are Not Managed?
Some people do not understand that natural resources need to be managed. After all, nature has been around
a very long time and can take care of itself, it is thought. Others think that more important issues and problems
face us and that managing natural resources does not merit the use of limited staff and financial resources.
While these are valid perspectives, they are not the whole story.
Studies over the last half century clearly demonstrate that, without management, natural resources change
in ways that are not always beneficial to people or supportive of ecosystem services (Alstad et al. 2016, Le
Maitre et al. 1996, Leach and Givnish 1996). A common problem in many unmanaged forests and woodlands
of Iowa City is invasion by non-native honeysuckle. When these non-native shrubs invade natural areas, a
cascade of negative effects occurs. Oak regeneration is suppressed, native shrubs decline, ground vegetation is
shaded, leading to the loss of soil-anchoring plants and increasing erosion. Flower resources for pollinators are
eliminated, reducing the amount and variety of food for other wildlife and depressing wildlife populations.
Large and ecologically complex regions may resist these negative trends, but natural resource quality generally
declines over time without proper management. This is especially true in small and scattered natural areas,
which is the situation in Iowa City. With some level of consistent management the situation can be stabilized
and even improved. For example, removing invasive honeysuckle from slopes in woodlands preserves the
soil and seedbank, and prevents sediment from reaching water bodies. This Natural Areas Plan identifies and
prioritizes the management actions which the City can implement to improve the health and resilience of its
natural areas and the ecosystem services and recreational benefits therein.
BACKGROUND, VISION, PRINCIPLES & GOALS | 9
2 Background, Vision, Principles & Goals
2.1 Background
Iowa City has a long history of providing its residents and visitors with a variety of outdoor recreational
opportunities, from parks for ball games and celebrations to natural areas for walking and running. The City’s
sustainability initiatives and recognition of the value of healthy ecosystems led to the City’s decision to improve
natural resources on City-owned land. This Natural Areas Plan will facilitate strategic investments in restoration
and management and help achieve the City’s natural areas and sustainability goals.
2.2 Vision Statement
Vision statements are created to convey aspirational goals for a specific endeavor. The following vision
statement was developed specifically for Iowa City’s Natural Areas Plan.
Iowa City recognizes the important role that natural areas play in an urban and suburban setting. The City’s
natural areas are a boon for local residents, an enjoyable and interactive experience for families, children,
and visitors, an outdoor classroom for students of all ages, and a home for a surprising variety of wildlife.
Maintaining an equitable distribution of natural landscapes throughout the City ensures that current and
future generations will continue to enjoy these resources. These renewed spaces will persist in supporting a
strong and diverse economy, fostering healthy and active lifestyles, advancing environmental sustainability,
and enhancing quality of life.
2.3 Planning Principles
Planning principles are guideposts, used to define how a project should unfold. Based on City goals and
discussions with staff, these planning principles were established for natural areas restoration and management
in Iowa City.
Overall
• Protect the City’s sensitive natural resources in order to foster resilient and biodiverse natural areas
within Iowa City
• Understand the historical and current conditions of natural areas to describe a future ecological path for
natural resources
• Design within the limits of existing soil, hydrology, and vegetation conditions
• Create attractive and resilient plant communities that can be managed economically
• Tell the ecological story of the City to inspire people through its restoration
• Bring people into the City’s natural areas while protecting biodiversity and ecosystem resilience
• Use indicators and monitoring to document trends in natural resources and determine the success of
restoration and management efforts
Vegetation
• Protect and restore the City’s rare ecological land cover types to prevent their disappearance
• Maintain and enhance common land cover types
• Promote a natural variety of native flowering plants across the growing season
• Control the invasive or aggressive native plants that reduce biodiversity and ecological resilience
• Establish a vegetation structure that requires the least effort to maintain
BACKGROUND, VISION, PRINCIPLES & GOALS | 10
Wildlife
• Protect, improve, and restore habitat for all wildlife
• Create the largest, roundest habitats for area-sensitive wildlife species (round habitats tend to be higher
quality because they resist negative edge effects from adjacent land uses)
• Design to reduce wildlife-damaging edge effects from adjacent properties
• Install special habitat features (nest boxes, etc.)
• Identify and seek to make connections to similar habitat on nearby conservation lands
Soil & Hydrology
• Preserve stable soils and natural hydrology
• Find solutions to eroding soils and damaged hydrology
• Protect neighboring properties from water damage
• Use vegetative stabilization and a natural ecosystems approach before resorting to more hard-armored
and engineered solutions
• Use a series of natural features (e.g., rain gardens, prairies, wetlands) to manage stormwater runoff from
impervious cover, beginning with reducing runoff at its source
• Design soil and hydrology solutions in the most cost-effective way possible
Human Use
• Separate minimum use sensitive natural areas from locations that can accommodate higher use
• Make management easier by defining management units and access points
• Detect problems early by monitoring trail and off-trail use
• Recruit organizations, experts and volunteers to help maintain and monitor natural areas
• Protect cultural resources
2.4 Project Goals
Based on the City’s request for proposals, consultation with AES, and the development of the project Vision and
Principles, the following goals and deliverables were identified for this Natural Areas Plan.
• A graphical/illustrative 10-year management plan for 42 City-owned natural areas that helps protect
functional, economic, recreational and aesthetic values
• High-resolution, multi-spectral aerial imagery
• Natural areas inventory, including field assessment of each natural area’s current conditions, native
and invasive species lists, issues/concerns, rare natural features, human uses, and GPS coordinates of
pertinent features
• Geographic information system database of all City-owned natural areas and collected data
• Recommendations for maintenance and enhancements (minimum/basic level and preferred level of
maintenance)
• Metrics to show progress toward STAR Community Goals (especially Invasive Species and Natural
Resource Protection)
• Identification of adjacent/nearby areas for improved ecological value and connectivity
• Review and recommendations regarding related City policies and ordinances
• Detailed tasks and priorities in the form of a 10-year management plan
BACKGROUND, VISION, PRINCIPLES & GOALS | 11
• Cost estimate for recommended tasks
• 12 meetings with Steering Committee
• Presentations to Iowa City Parks Commission (draft report) and Iowa City Council meeting
(final report)
• Fifteen (15) bound copies of final report
• Final Natural Areas Inventory Map (poster)
DATA AND METHODS | 12
3 Data and Methods
3.1 Existing Data Review
To assess the City’s regional context, existing ecological conditions, management opportunities, and constraints
on City-owned natural areas, AES reviewed previous studies and other existing data including, but not limited to:
Natural Resource-Related Data
• Iowa City Natural Areas Inventory, Management Needs and Assessment (City of Iowa City 2016)
• STAR (Sustainability Tools for Assessing and Rating Communities) Certification Results Report (STAR
Community Rating 2016)
• Iowa City - City Code (http://www.sterlingcodifiers.com/codebook/index.php?book_id=953)
• Numerous park and natural area-specific studies, including mitigation monitoring reports, planting/
seeding lists, and prescribed burn plans (see Appendix B, Management Briefs for site-specific data
listings)
• Iowa Department of Natural Resources (Iowa DNR) “Landform Regions of Iowa” (Iowa DNR 2016a)
• Ecoregions of Iowa and Missouri (Chapman et al. 2002)
• Landforms of Iowa (Iowa DNR 2015)
• Iowa DNR Indiana bat guidelines (Iowa DNR, no date)
• Known Northern Long-eared Bat Hibernacula and Roost Trees in Iowa (USFWS 2016a)
• Final 4(d) Rule for the Northern Long-Eared Bat (USFWS 2016b)
• Northern Long-Eared Bat Final 4(d) Rule, White-Nose Syndrome Zone Around WNS/Pd Positive Counties/
Districts (USFWS 2017)
• Securing a Future for Fish and Wildlife: A Conservation Legacy for Iowans (Iowa DNR 2015)
AES also compiled and reviewed existing City geographic information system and other digital mapping data
including:
• Iowa City limits
• Iowa City park and natural area boundaries
• Elevation data from Light Detection and Ranging (LiDAR)
• U.S. Department of Agriculture/Natural Resources Conservation Service digital soils data
• U.S. Fish & Wildlife Service National Wetlands Inventory (NWI)
• National Land Cover Dataset (NLCD)
• Aerial photography (historical and 2016 flight by AES, true-color and infra-red)
• Original Vegetation of Iowa (General Land Office mapping)
• Geologic mapping
• Hydrography data
• Iowa DNR Natural Heritage Information System rare features data and reported high quality
communities (Iowa DNR 2017b)
3.2 Aerial Imagery
Aerial imagery is a powerful tool for inventorying and managing natural resources, as well as documenting and
monitoring City infrastructure. For this project, vegetation community mapping and identification of invasive
woody shrubs was the chief interest. Some invasive plants can be seen on aerial imagery on the basis of their
life history patterns. For example, invasive honeysuckle, buckthorn, and multiflora rose tend to retain green
DATA AND METHODS | 13
leaves into late fall. Areas of these invasive shrubs, from photographs taken in the late fall, show up as reddish in
color infrared imagery.
AES was directed by Iowa City to collect high resolution, multi-spectral aerial imagery of the entire city. Using a
Leica RCD 30 multi-spectral digital camera, this imagery was collected on November 10, 2016. An airplane with
the camera mounted in its belly flew multiple flight lines across Iowa City, taking pictures at regular intervals and
covering the entire City with aerial imagery (Figure 1). Four different light wavelengths were captured by the
camera: infrared, red, green and blue (IR RGB).
Figure 1. Flight plan for collecting Iowa City aerial imagery showing flight paths along which photos were taken.
The camera resolution was 6 inches on the ground, also known as ground sample distance (GSD). The
captured imagery was processed into a digital image file that contains both the natural RGB color and infrared
bands. Combining these four spectra in different ways allows the user to represent the data in different ways
for different purposes. For this natural areas inventory, the imagery provided an up-to-date and accurate
representation of the ecological landscape of the City’s parkland for AES field ecologists to inspect before and
while visiting the sites. The imagery was used to map plant communities, identify invasive woody plants, and
provide high-resolution imagery to compare with future imagery. In addition, the imagery can be used to
inventory urban trees, document stream conditions, and assess infrastructure condition. Example imagery from
a location in Iowa City is shown in the following images.
DATA AND METHODS | 14
Natural color image: colors appear as they do to the human eye.
Infrared color image: colors represent the infrared spectrum, showing areas in red where vegetation is actively growing.
Normalized Difference Vegetation Index (NDVI): this method of data presentation shows a gradient of
“greenness” in which impervious cover is red.
DATA AND METHODS | 15
For more information on aerial imagery, see:
• Infrared imagery: http://www.aerialarchives.com/infraredcolors.htm
• Normalized Difference Vegetation Index (NDVI): https://phenology.cr.usgs.gov/ndvi_foundation.php
• Using aerial imagery for invasive species management: https://www.fs.fed.us/eng/rsac/invasivespecies/
3.3 Desktop Methods
As a platform for developing and managing Iowa City’s natural area vegetation data, AES built an ArcGISTM
geodatabase. (A geodatabase is a collection of geographic datasets of various types held in a common file
system folder or database.) Developing the geodatabase began with compilation of existing geospatial data,
including City buildings; impervious surfaces; existing natural resource data layers such as elevation contours
and wetlands mapping; historical aerial photographs; and the high-resolution multi-spectral aerial imagery
collected by AES in fall 2016. Using these data, major land cover types were digitized (i.e., outlined) in the
geographic information system.
A powerful feature of a geographic information system is that multiple characteristics or “attributes” can be
assigned to each area or “polygon.” A land cover classification system appropriate for Iowa City natural areas
management was developed and approved by the City, and preliminary land cover types were assigned to
polygons of different plant communities in each park and natural area, to be confirmed later in the field.
Using geographic information system data layers and other sources, a variety of quality assurance/quality
control procedures were followed to ensure initial vegetation mapping was as accurate as possible. This entailed
making visual, on-screen comparisons among geographic information system datasets. The digitized land cover
polygons were compared to recent aerial imagery, elevation contours, and other datasets. Edits to polygon
geometry and attribute codes were made as warranted. This desktop mapping was used to create maps for use
in the field assessment.
A comprehensive plant species list for Iowa City was compiled from previously published work in Iowa City and
the surrounding area (Appendix C). The list was updated to reflect current species nomenclature (with the U.S.
Department of Agriculture “Plants” website serving as guidance for the standard names accepted by federal
agencies) and nomenclature used commonly in the region. The species list was later expanded to include plant
species observed by AES in its field assessment that were missing from the original compilation. Not all species
in Appendix C were observed by AES during its assessment.
3.4 Field Assessment Methods
In April, June and July 2017, AES ecologists conducted field inventories and assessments of 42 parks and
natural areas in Iowa City. Field maps were used to verify and refine plant community classifications and plant
community boundaries, and to assign a quality rank conveying the area’s ecological quality. Quality ranks
consider a variety of ecological criteria:
• Diversity of native species
• Level of disturbance
• Presence of invasive species
• Structural and spatial diversity (i.e., vegetation layers and plant variety across the natural area)
• Connectivity with other plant communities versus to turf or active use park areas
• Degree of erosion due to processes such as excessive runoff or foot traffic
• Other negative management or use effects observed
All of these criteria were considered for each plant community assessed in Iowa City, but quality ranks were
most influenced by the abundance of invasive plant species. Using the criteria above, quality ranks were defined
as follows:
DATA AND METHODS | 16
• A = High quality natural community. No damaging disturbances evident and natural processes are intact.
• B = Good quality natural community. Natural processes are intact, but signs of past human impacts are
evident. Low levels of invasive plants are present.
• C = Moderate condition natural community. Obvious past disturbance evident, but still clearly
recognizable as a native plant community. Not dominated by weedy species in any layer.
• D = Poor condition natural community. Includes some native plants, but is dominated by
non-natives and/or is obviously disturbed or altered throughout.
• NN = Altered/non-native plant community. These semi-natural communities do not receive
a natural quality rank.
Often, a mapped plant community may be heterogeneous with different areas having characteristics of more
than one quality rank. For instance, a moderate quality forest (C rank) may have large, dense patches of invasive
buckthorn (justifying a D rank). In this case, the rank assigned to this single plant community is CD.
Species lists were recorded for each unique plant community type present at each of the 42 sites surveyed and
a categorical cover class (based on percent cover) was assigned for each species in that community. Invasive
species were noted, both by cover class and general distribution within the plant community. Species lists were
generated by a random walk and were not intended to be comprehensive but strove to capture the dominant
species in three structural layers: canopy, shrub/vine/sapling, and herbaceous. Notable/representative species
were also recorded to support plant community classifications.
Digital photography (georeferenced, using Collector for ArcGIS and ArcGIS Online) was used to document
representative plant communities, discrete concentrations of invasive vegetation, erosion features, and other
notable aspects of the City’s natural areas. Desktop refinement of geographic information system data was
conducted after field inventory and assessment, resulting in detailed land cover maps of each site (included in
Appendix B).
CITY-WIDE ECOLOGICAL CONDITIONS & ASSESSMENT | 17
4 City-Wide Ecological Conditions & Assessment
4.1 Regional Context
Iowa City is located in the east-central portion of the state in Johnson County (Exhibit 1). The City’s 16,588 acres
contain a mix of urban land uses (including commercial and moderate-density residential in the central portion
of the City) and low-density residential and agricultural land closer to the city limits. The cities of Coralville
and North Liberty lie just northwest of Iowa City, and Cedar Rapids is approximately 20 miles north-northwest
of the City. The Iowa River flows south through the center of Iowa City. Large natural areas in the vicinity of
Iowa City are Lake Macbride State Park (approximately 7 miles north) and Hawkeye Wildlife Management Area
(approximately 10 miles northwest).
4.2 Landforms, Soils and Water Features
Iowa City exhibits a variety of landforms due to the glacial and geologic history of the region (Exhibit 2). These
“landform regions” are defined by their internally distinctive geology, soils, slopes and elevations (Figure 2).
Figure 2. Landform regions of Iowa (Iowa DNR 2015).
Iowa City spans two landforms: the Southern Iowa Drift Plain and the Iowa-Cedar Lowland. The former covers
most of the City and the latter is primarily along the Iowa River in the southern part of Iowa City.
The Southern Iowa Drift Plain is a tallgrass prairie region, part of the great Midwestern Corn Belt. It is almost
entirely glacial drift from Pre-Illinoisan glaciers over 1 million years ago. The glacial drift is a few to several
hundred meters thick. Because the drift is so old, streams have eroded the land and formed well-defined,
regularly-branching drainages. Hilltops are at a similar elevation at about the land surface deposited by glaciers.
After the glaciers retreated, wind-blown fine sediment called loess fell on the landscape to a depth of 2 to 10
meters. Around 10,000-13,000 years ago, large rivers like the Iowa had glaciers in their headwaters. As the