The Natural World




How the Natural World Is Organized

Understanding Wildlife Populations and Communities

Understanding Plant Populations and Communities

Putting the Pieces Together

Myth or Fact?

Table 2.1 Problem Plants

Suggested Reading

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Preparing a wildlife habitat management plan without having a basic understanding of wildlife and plant ecology could be compared to doing your own car repairs without knowing how an engine works - you might luck out, but you’re more likely to run into trouble. This chapter explains fundamental ecological concepts to lay the foundation for sound habitat management.

 
     
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The management activities that biologists recommend to help our natural world are based on ecology-the scientific study of the interactions and interrelationships of plants, animals, and their environments. In keeping with the human need to organize the way we view the world, the scientific community has defined categories for how the natural world is organized and functions. The broadest unit is the ecological system, or ecosystem, a term used in the field of ecology for the last hundred years. An ecosystem consists of all the plants, animals, and other living organisms, plus their environment, in a given area. The abiotic resources are the nonliving portion of the ecosystem, made up of physical components such as air, water, soil, bedrock, and climate.

The living part of the ecosystem is referred to as the biotic community, or the groups of organisms living together in a specific area. The terms plant community (or vegetative community) and animal community refer to specific groups of organisms. Communities are made up of collective populations of plants and animals. A population is all the individuals of one species.

Wildlife management is conducted at each of these levels: the ecosystem level, the community level, and the population level. For example, the manipulation of water depth in a wetland, by altering both the living and nonliving parts of the wetland, would be considered ecosystem management. Still larger scale ecosystem management would involve an entire watershed. An example of community-level management is prescribed burning on a prairie. Such burning is conducted specifically to manipulate plant communities. White-tailed deer are managed at the population level in Illinois by regulation of their annual harvest. Another recent example of population management is bringing in prairie chickens from other states to increase the diversity of the gene pool in our endangered Illinois flocks. To be effective, wildlife management must be based on the systems and processes inherent in nature. Understanding ecosystems is key to successful wildlife habitat projects.

One of the more confusing aspects of understanding ecosystems is size: How big is an ecosystem? Actually, an ecosystem can be any size. A pond can be an ecosystem. So can a forest. A crop field can be an ecosystem, as can a cliff, a cave, or a backyard. But an ecosystem can also be huge-the Yellowstone ecosystem, for instance, covers parts of three states and encompasses a variety of community types. An example in our state is the Illinois River ecosystem, which includes the river and its entire watershed. Yet there are many smaller ecosystems within this larger one. The bottomland forests and the backwater lakes found along the river can be viewed as individual ecosystems.

The concept of ecosystems is broad so that it can be used in a variety of circumstances to study and manage the natural world. For property owners, the ecosystems most important to consider for wildlife are grasslands, woodlands, wetlands, and croplands. Later we will discuss how these relate to the larger landscape of which a given piece of property is a part.

Be aware that there is some misused terminology in the vocabulary of modern wildlife management. The terms ecosystem, vegetative community, and habitat type are often used interchangeably. In this book, discussion of "habitat type" generally refers to a community dominated by a group of plants (woody for woodlands, herbaceous for grasslands) or a community defined by a dominant physical characteristic, such as the presence of water in an aquatic habitat, or by intensive disturbance, as in croplands. Often biologists will also use the term ecosystem as they do habitat, and they will further be referring to a community type. You might hear a prairie called a prairie ecosystem, a prairie community, or a prairie habitat. Since a prairie can be all of these things in the purest sense of their definitions, all of these usages are correct.

There are a number of important characteristics to understand about ecosystems. One is that all their components, both living and nonliving, are connected and dependent-to a greater or lesser extent-on each other. For example, if you remove a large predator species, like a wolf, from an ecosystem, a major shift will result both in the prey populations and in the vegetation and the other creatures that the prey feed on. The chain reaction continues as the vegetation is altered and populations of small invertebrates change, which affects in turn the soil and water.

Ecosystem complexity is also important to understand. An ecosystem can be fairly simple, like an agricultural field that contains only one planted crop, a few weeds, and a handful of animals. In this type of system the interaction between plants, animals, and physical components is relatively simple. But natural ecosystems that have been less altered by humans usually have a much larger variety of plant and animal species. The original Illinois prairie ecosystem, for example, contained as many as 300 plant species. The variety of an ecosystem's biotic community is often referred to as its biodiversity. The more biodiversity within an ecosystem, the more numbers and kinds of plants and animals are found there.

In wildlife habitat protection and creation, maintaining or enhancing ecosystem complexity is usually a primary goal. A complex ecosystem usually attracts and supports more wildlife. It is generally more resilient to damage or complete destruction by uncontrolled fire, disease, storms, and other disturbances, both natural and human-induced. It is important to understand, however, that patience is paramount in habitat restoration work. Habitat establishment aimed at re-creating a complex ecosystem takes time. Establishing vegetation is only the first link in a chain of events that will eventually result in high-quality wildlife habitat. Soil microbes need to establish; insects and invertebrates need to move in. In time, animal species dependent on them will appear.

All species contribute something toward the healthy functioning of an ecosystem. But too often people have decided arbitrarily to eliminate some part of an ecosystem without regard for its importance to the whole. A classic example has been the systematic destruction of snakes-even by those who profess to be conservationists. Yet snakes play a very important role in every ecosystem where they live. Many landowners try to invite wildlife to their property, but if an undesired creature shows up, it is killed or driven off.

There are instances in which wildlife can threaten human-built structures-woodpeckers and wood-sided homes, for example. If an animal is causing specific damage, control may be necessary, although methods other than killing are usually possible and preferable. It is common when landowners are trying to establish habitat that certain species will hamper their efforts. For example, rabbits and deer may feed on newly planted trees, shrubs, and wildflowers. Beaver will sometimes cut down forest plantings or retard the establishment of woody cover in stream-bank stabilization projects. In these types of cases, some sort of repellent or control may be necessary.

The rule of thumb is this: Never eliminate wildlife just because you don't like it. If an animal causes serious damage or poses a serious health hazard, first consider methods of discouraging it. If this fails and removal or elimination is necessary, consult an Illinois Department of Natural Resources biologist. Most animals are protected by law, and killing an animal without authorization can result in a stiff penalty. Wildlife populations can often be managed through regulated hunting and trapping so they don't become a nuisance.

Remember, each species has an important role in nature, and if you're interested in building and maintaining the best wildlife habitat possible, you need to make room for all wildlife in the ecosystem.

Ecosystems are subject to a variety of processes. Rather than being static, ecosystems are dynamic. Change is always occurring as plants and animals struggle among themselves and with other plants and animals for survival. Factors such as weather, fire, and floods also create change in ecosystems. It is important to understand, too, that not only do changes in the physical environment affect the biotic community, but the reverse is true as well-changes in the plants and animals can affect their environment. A significant fluctuation in the plants or animals inhabiting a pond can change the water's chemistry-a massive die-off of algae in a pond can deplete oxygen, for example. Or if a disturbance removes a large portion of tree and ground cover in a forest, sunlight penetrates to the newly exposed soil and raises the ground-level temperatures. In both of these instances, the change in the physical environment would spur further change by affecting the biotic community-the pond inhabitants in the first example and the soil and the leaf-litter dwellers in the second.

Change of any kind in the biotic community or its environment creates changes in the whole ecosystem. Change can be favorable or unfavorable depending on the species in question. Usually an ecosystem fluctuation favors some plants and animals and not others. However, natural change in ecosystems should not be viewed overall as a negative process.

Humans have caused great changes in Illinois ecosystems, often to the detriment of individual ecosystems. But human-created disturbances can also be used to undo some of the damage we've done. Our ability to effect change in portions of an ecosystem for the benefit of wildlife is at the heart of this book. A landowner can establish specific plants on a site, manipulate water levels in a wetland, or introduce fire-all of which, if done for a specific purpose, can improve conditions for wildlife.

Let's address more specifics on the biotic components in ecosystems.

 
     
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To begin understanding the life requirements of wildlife, we need look no farther than the needs of a familiar animal: the human. Just like us, wildlife require four basic elements to live: water, food, shelter, and space. Food and water are prerequisites to sustaining life; shelter-from weather, from enemies, and for raising young-perpetuates life. And all animals need physical space for themselves and their families, although the amount needed varies among species.

Habitat is what provides all of these elements for wildlife. The term habitat is used in several ways, but it is basically defined as a living environment. The term can be used singly (an animal's habitat) or collectively (wildlife habitat). The word is also used to define a type of living environment. Our management recommendations address four predominant Illinois habitat types: grasslands, woodlands, wetlands, and croplands.

Some wildlife species may be able to satisfy all four basic needs in one type of habitat. Other species have complex needs and require several habitats to secure adequate food, water, shelter, and space. The collective area needed by an individual animal to meet its normal living requirements is known as its home range.

An animal's home range should not be confused with its natural range, which refers to the geographic area in which the species can be found. For example, the natural range of the eastern chipmunk includes eastern Canada and the eastern half of the U.S. But an individual chipmunk's home range is from less than half an acre to three acres, depending on local conditions.

Home-range size applies to individuals within a species and varies between species. For some, such as the white-tailed deer and the great-horned owl, a home range may encompass one to four square miles. The home ranges of other animals, such as the shorttailed shrew and the spotted salamander, may be just a quarter of an acre. Still other species, including migratory hummingbirds and warblers, have home ranges that may vary seasonally and may be located on two continents. The home range may also vary slightly for any species depending on the quality of available habitat.

Here's an illustration of a species' home range: The ring-necked pheasant has needs that differ between seasons, and to meet those needs it must use several habitats. During much of the year, this bird can be seen roaming the open agricultural fields of central and northern Illinois. For breeding and nesting, however, the female needs to find an undisturbed (unmowed) grassy field that will hide her eggs and provide insects for her newly hatched clficks. And during severe winter weather, the birds need thick, erect vegetation, such as cattails, prairie grass, or brushy cover, for shelter. The area required to meet these needs, generally one square mile in Illinois, is the pheasant's home range. However, individuals have been known to disperse as far as 15 miles when needed to fulfill their living requirements.

When an element necessary to a species' survival is in short supply or completely absent, it is referred to as a limiting factor. Because wildlife have complex and varied needs, the lack of any particular element can limit population size or even prevent a species from inhabiting an area. For instance, a woodlot may be filled with mast-bearing oak and hickory trees that produce enough food for twenty squirrels. But if the woodlot contains only a couple of trees with cavities, the squirrel population will be limited by the availability of secure sites for raising young. The area probably cannot support twenty adult squirrels because of a limiting factor-insufficient nesting sites.

Most of today's limiting factors for Illinois wildlife are caused by habitat degradation and elimination. Natural occurrences such as weather extremes, disease, and lack of food can also be limiting factors.

Some landowners become disappointed that habitat development or enhancement doesn't produce immediate results, or the results they expected. They wonder why their grass planting has failed to attract quail or why they don't have wood ducks in their newly created marsh. The reason is probably a missing habitat element or an unapparent limiting factor that has prevented the local population from expanding into the landowner's "new" habitat. Landowners should not let such a situation discourage their habitat development; improvements targeted at a specific species often work with time, provided the property is within the animals' normal geographic range. Sometimes a particular limiting factor will be eliminated after habitat plantings have become well established. For example, the simple presence of grass may not be enough for certain grassland birds. Some species, such as the Henslow's sparrow and the sedge wren, need undisturbed grassy areas that have accumulated a couple years of dead grass thatch. A first-year planting cannot provide this.

Ecosystems are dynamic, and the populations within them fluctuate from year to year. But on average, all habitats can support only so many animals of any given type. This limit is defined as an area's carrying capacity. When too many animals of a species are born into or immigrate into an area that is at its carrying capacity, some animals will have to go, either by leaving or by dying. The carrying capacity for any species varies seasonally and yearly, depending on the presence or absence of limiting factors. During a drought year, for example, fruit-bearing trees and shrubs may produce less fruit than usual, and the carrying capacity of the drought area would likely be reduced for the wildlife species that subsist on the fruit.

Many species produce an overabundance of offspring each year to ensure an adequate survival rate. If"new" suitable habitat has been created near existing habitat, some of the surplus animals will move into the new area. But if there is no new habitat for dispersal, the surplus animals are eliminated through starvation, predation, or disease. Hunting and trapping are regulated to use the surplus without destroying the base population.

The principles of carrying capacity continually determine population sizes and viability. Landowners trying to increase wildlife populations must understand that wildlife cannot be stockpiled; populations will always be limited by the amount and quality of habitat available to them.

 
     
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Although the biotic community includes all the living organisms, plant and animal, occupying a particular area, it is often referred to by its dominant vegetation. For instance, in Illinois you might hear of an oak-hickory forest community, a cattail marsh community, or a prairie grass community.

However, while communities are generally identifiable, the landscape doesn't always consist of neatly defined parcels. Where different vegetative communities meet there is often some overlap, creating a transition zone called an ecotone. Ecotones are often subject to great fluctuation because disturbances usually affect the two adjoining communities differently. For example, the ecotone between a forest and a grassland would contain some shrubby plants and maybe a few scattered trees, with lots of grassland plants beneath them. If a fire were to burn the grassland and the edge of the woods, some of the woody plants in the ecotone would be destroyed and the grass would flourish. The edge of the woods would be opened to sunlight, creating more favorable conditions for the grassland plants. The change would allow the grassland to advance a little into the forest.

While ongoing change is not always apparent, plant communities are dynamic rather than static entities. All land in Illinois, whether backyard, corn field, or bottomland forest, is subject to a process called succession. Succession describes the continuous, fairly predictable change of plant species and plant communities over time. The ongoing competition among various plants and plant communities to establish themselves on the landscape is why succession occurs. How it occurs is a matter of biology. Different types of plants have different life cycles and adaptations for surviving in the environment, and over time some plant species and groups of plants will naturally be better adapted to local conditions.

When does succession occur? It happens continually on a small scale. Large-scale succession of whole plant communities, though, occurs whenever there is a major change in an area's environment. Natural disturbances such as floods, tornados, and severe icestormscan damage or destroy an existing community, and a major successional course usually begins.

In Illinois, the human activities most often leading to succession of plant communities are abandonment of agricultural fields and logging. Yet the process of succession can be observed right outside our homes. Any time a tree pops up in an unmowed area or weeds appear in a newly plowed garden, succession is in progress. What keeps our backyards from becoming woodlands are lawnmowers, herbicides, and garden tillers.

If it is allowed to proceed without disturbance, plant succession has fairly predictable stages and outcomes. Generally, in much of Illinois today, the process of succession in a bare field starts with the pioneer stage of annual plants, which eventually are largely replaced by perennial herbaceous plants, then shrubs and trees, and ultimately a mature forest. Here's an example of what could predictably happen if an upland central Illinois crop field were permanently abandoned, with no further human interference: First it would be iny'o \ded by herbaceous annuals such as foxtail and ragweed. After two or three years, perennial herbaceous plants like goldenrod and milkweed and grasses like smooth brome or bluegrass would get firmly established, outcompeting and replacing many of the annuals. Assuming a local seed source was present, after another two to three years, woody species such as dogwood and elderberry shrubs and seedlings of invader trees such as silver maple, eastern redcedar, mulberry, and box elder would begin appearing. As the woody species developed extensive root systems and increasingly shaded the ground, they would dominate the site. As the invader trees grew, a young forest would develop. Eventually (in twenty to forty years), the trees would sort themselves out, and certain species would dominate to form the canopy of a maturing forest.

Most of Illinois' openland habitats-grassland and cropland would ultimately revert to woody cover if left undisturbed. Which plants would appear during the course of succession would be dictated first by what seed sources were in the area and second by the specific physical conditions of the site (drainage, soil type, slope, etc.).

When disturbance is introduced during succession, the process can be either retarded or encouraged. Much of the Illinois land used for agriculture is intentionally kept at an early successional stage by periodic tillage. For the landowner trying to reconstruct some type of habitat, such as a woodland, minimizing tillage, mowing, and other disturbances should encourage successional progress to that targeted community type. For other habitat reconstructions, such as grass lands, periodic disturbance (fire, mowing, discing, herbicides) is necessary to prevent woody encroachment and to help the herbaceous plants flourish. Strange as it may sound, many mature communities have evolved to actually depend on certain disturbances to prevent succession. For example, many oak-hickory forests need fire to keep them from succeeding to a forest of maple and other shade-tolerant species. Many grasslands need fire to prevent them from succeeding to woody cover. Bottomland wetlands need periodic flooding to flush accumulated organic debris so they do not succeed to woodlands.

Manipulating the succession of habitat, by either retarding it or enhancing it, is the basis of much of wildlife habitat management. But it is important to remember that even if you're managing for an eventually "stable" community, there will always be some ongoing successional change. You can't freeze nature into an oil painting of exactly the plant species you want, just where you want them. This doesn't mean that you won't eventually have a prairie or woods that seems relatively unchanged over the years. What it does mean is that certain plants you introduce during establishment of your habitat may, for one reason or another, not be able to persist or compete with the others and will eventually disappear.

Here are some additional points to be aware of about succession:

  • It is easy to create early successional habitats simply by applying some sort of disturbance. But we cannot reconstruct a mature, later-successional-stage community in a short period. For example, we must simply wait out the time necessary for trees to grow to their mature state. We can, though, have limited impact on the efficiency with which that growth happens. For example, we can plant desirable trees such as oaks and hickories and at the same time suppress shade-tolerant trees to give the slower-growing oaks and hickories maximum growth opportunities. Given the lengthy time it takes to re-create mature communities, especially the forested types, it should always be a priority to preserve those that already exist.


  • The process of succession in Illinois has been affected by the widespread establishment of non-native plants, which sometimes outcompete native species. As a result, we must often "assist" in succession if the goal is to establish a diverse, specific community of native plants. Fescue, for example, can become so thick that it prohibits the establishment of most woody vegetation. And aggressive exotics such as Tartarian or Amur honeysuckle can suppress native, slower-growing trees such as the oaks. These exotic shrubs can quickly dominate and shade the forest floor and prevent sun-loving oak seedlings from establishing.


  • Since wildlife have specifi,c habitat needs, succession of plant communities also results in some continuing change of corresponding wildlife communities.

Because controlling or encouraging succession is pivotal in wildlife habitat management, chapters 4, 5, and 6 discuss succession for each habitat in detail.

Understanding how plant and animal populations function and interact with their environment builds a foundation for good habitat management. The next step is to translate that knowledge from these pages into the real world-the everyday management of your parcel of land. But for wildlife the "real world" isn't defined by legal property boundaries. In our state, their reality is the collective landscape we call Illinois, an intricate mosaic of overlapping home ranges of various animal species. Since wildlife operate within their own boundaries and not those of humans, we must look at the bigger picture to make the best land management decisions.

We have discussed habitats as individual units of management. When we look at the landscape, these units form various patterns. While the quality within these units is important, the size and arrangement of these units on the landscape also affect their suitability for various wildlife species.

Interspersion refers to the proximity of different habitat types. The interspersion of habitats is directly related to the size and arrangement of the units, and it affects what animal species will occupy them. Several small tracts of different habitat types in close proximity means there is high interspersion, and vice versa.

Interspersion is an important consideration in habitat management planning. Some species may require large, unfragmented tracts of a single habitat type (no interspersion). Other wildlife may need several habitat types (high interspersion), all of which can be small patches but that must be spaced close together. Many species thrive in edge habitat, which is created with higher interspersion. Edge habitat-which exists where two habitat areas meet, such as a brushy fencerow and a crop field or a grassland and a forest contains animal species from both adjacent habitats and also supports wildlife that prefer edge, such as cardinals, cottontails, and common yellowthroats.

Two illustrations reveal the importance of considering interspersion. Ovenbirds require several hundred acres of unbroken, mature forest for successful breeding, and they have evolved to procure all the necessary elements from that one habitat in the summer. Smaller patches of habitat make them vulnerable to competition from other species, such as the brown-headed cowbird, and to increased predation by abundant edge-dwelling predators like raccoons. On the other hand, cottontail rabbits need several types of habitat, and because they are not extremely mobile (as most birds are) they need to have the habitats close together. They are often found in edge habitats as opposed to deep forest interior.

Interspersion is not the only consideration that influences habitat suitability. Whether valuable habitats are isolated or connected also determines the landscape's usefulness to most wildlife species. For example, let's say a thirty-acre woodland sits in the middle of 900 acres of crop field, and the nearest woody cover is three miles away. Less mobile species of wildlife, such as reptiles, amphibians, and small mammals, would be unable to travel between the two woodlands. The animals in the thirty acres would be isolated and more susceptible to the effects of inbreeding and adverse weather events. As species disappeared from the island woods, the biodiversity of this forest would decrease and it would eventually support only mobile generalist species, like white-tailed deer and robins.

If, on the other hand, strips or fencerows of woody vegetation existed between the two woodland tracts, genetic intermixing could occur via these corridors. Corridors used to be more numerous in Illinois. The elimination of hedgerows coupled with our continued penchant for "tidy" landscapes has led to the removal of many of our weedy, brushy, and tree-filled windbreaks and fencerows.

Earlier we discussed biodiversity within ecosystems. When we look at the Illinois landscape, biodiversity between ecosystems is also critical. The Illinois Natural Areas Inventory that was conducted in the late 1970s categorized, for the first time, nearly all of the natural community types historically known for our state. Approximately eighty-five communities were recognized. Preserving and restoring this diversity of distinct communities on the Illinois landscape is essential to preserving our variety of wildlife.

 
     
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As you can probably now see, managing for wildlife can include many elements. So how do you, the individual landowner, determine the appropriate habitat to construct or preserve-in the right place and of the right size-for the myriad of Illinois wildlife?

While species are sometimes managed individually, the most efficient way to manage is to consider groups of species that occupy common habitats. This is why most land management revolves around habitat types. Many species use several habitats but prefer one primary type. Generally, if a woodland is managed for woodland wildlife, most species that use this habitat will benefit.

Trying to restore Illinois habitats as we believe they existed prior to European settlement is a way to benefit native species with specific requirements. (See The Natural Divisions of Illinois referenced for a better understanding of the historic Illinois landscape.) While this book discusses the use of certain non-native plants, the primary emphasis is native plants and plant communities. Where possible and practical, we should use nature as the gold standard to measure our actions.

One of a landowner’s most important management considerations is to take a three-dimensional view of wildlife habitat. From the treetops to deep in the soil to the horizon beyond a properly boundary - this is the habitat where wildlife live. Habitat types and home ranges transcend political and legal boundaries and stretch beyond immediate human vision. Try to view the landscape from a wildlife perspective.

Often we act by considering only short-term economic factors. Taking a more holistic view is usually the best approach. Unfortunately, not thinking broadly enough h~s resulted in a fragmented effort to conserve and restore Illinois' wildlife habitat. But government agencies and private conservation organizations have recently begun to consider a larger "landscape level," or ecosystem-based, approach to their wildlife management activities. Landowners ought to do the same if they desire to restore and retain a diversity of wildlife.

The final point to be learned from lessons of ecology is that wildlife are affected, either negatively or positively, by whatever a landowner does to his or her property-including doing nothing. No Illinois landowner can be passive and claim not to be part of the problem or the solution. The fate of Illinois wildlife rests in the hands of private landowners. With a foundation of basic environmental knowledge, each landowner can make land management choices that build the sustainability of our natural resources.

 
     
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There are many widely held beliefs about wildlife that are accepted as fact. On the surface these beliefs may seem very logical. However, once you understand how the natural world functions, you question them. Understanding concepts such as plant community succession, basic needs of wildlife, and carrying capacity helps dispel many of these myths. Some common myths and the related facts are detailed here.

Myth: Wildlife are starving:

Facts: Wildlife that feed on seeds or grains are far from starving in Illinois. With nearly 80% of our land used for agriculture, and with conservation tillage increasing in our state, food for many wildlife species is abundant in crop fields. And most seed-eaters opt for a variety of foods, including weed seeds and other plant materials. Wildlife can experience hardship in winter when ice or deep snows blanket the ground for days or weeks. But it is the lack of cover, not of food, that usually kills wildlife in the winter.

A different aspect of wildlife food supply is of serious concern. Widespread pesticide use on our yards and farms and loss of vegetation, such as small grains and legumes, have greatly reduced insect populations. Hundreds of bird, mammal, reptile, and amphibian species depend on these invertebrates for food. They are an essential food for young pheasant and Bobwhite quail chicks, and many songbirds eat insects almost exclusively. While many people would argue that we still have more than enough insects, certain wildlife species are likely experiencing a reduction of necessary foods in some instances.

Myth: Hunting and trapping are the reason many wildlife species have declined

Facts: Hunting and trapping have not contributed to the decline of wildlife since the days of unregulated mass harvesting for markets. Today both activities are carefully controlled by state and federal conservation agencies, based on the principle of carrying capacity. Harvest limits are set in accordance with statistical analyses of species' year-to-year populations. Species that are hunted and trapped are those whose populations are flourishing enough to produce a surplus.

Myth: Releasing hand-reared birds builds up local populations.

Facts: Numerous studies have shown that pen-raised birds such as quail and pheasants don't survive long in the wild once they've been released. They don't fear predators, don't know how to seek cover from inclement weather, and may be inept at finding food. And if an area is already supporting all the animals it can (it is at its carrying capacity), adding new individuals only results in a surplus that is eliminated in a few months. Releasing pheasants or quail to supplement a hunting program can be acceptable, but doing it to increase an existing population is a waste of time and money. A better use of those resources would be expanding existing habitat to allow natural population growth.

Some people wonder, if we can successfully raise and release certain endangered species to reestablish a population, why won't it work for all wildlife? Most captive-breeding programs for endangered species work to reestablish an animal to a former range where habitat conditions have taken a turn for the better or where a harmful factor or element, such as the insecticide DDT, no longer threatens a species. Depending on the species, the animals are bred and released into the wild at a young age, or they are raised in a semi-wild environment, carefully controlled to simulate a natural situation.

Myth: Because the state has successfully established new populations of some animals through trap-and-transplant, this should work for any species.

Facts: The wild turkey and the river otter are two species that practically disappeared due to habitat elimination, habitat degradation, and uncontrolled harvesting. Even when these factors improved, physical barriers prevented both species from reestablishing in their former ranges.

The wild turkey was over harvested at the same time its habitat was disappearing. Once harvesting was banned and then subsequently regulated, and some habitat restoration had occurred, the species still wasn't recovering. The birds wouldn't cross towns or large expanses of open agricultural land to repopulate formerly inhabited areas. Biologists assisted by transplanting the wildlife.

The river otter declined initially due to unregulated trapping, and it suffered further declines from the poor water quality that developed in Illinois around 1900. Water quality has improved significantly in some Illinois rivers and streams,.but the otters cannot always travel long distances to reinhabit their recently improved former habitats. Transplanting worked because the factors negatively affecting the species were resolved.

There are additional animals that could be successfully transplanted, but only after long and careful evaluation by qualified biologists. Numerous habitat conditions must be met before any species can be reestablished. One or more habitat elements are missing for many of the species that have declined in or disappeared from Illinois, in which case transplanting would not be successful.

Myth: The best thing I can do for my land is to let it go "back to nature. "

Facts: Nearly all habitats in Illinois today, natural or created by humans, need some form of management.

We have altered the landscape and the dynamics of nature so drastically in our state that most systems are hindered in returning to a native and natural state without our help. Even the high-quality remnant communities scattered around Illinois usually need some assistance to respond to the onslaught of changes we've thrust onto the landscape. For example; we eliminated the natural process of fire, but we now understand its critical role in sustaining many natural communities. And the unabated march of invasive exotic plants into our natural communities will not cease without our help.

Myth: New and improved varieties of shrubs and trees are better to plant because they grow much faster and provide better habitat.

Facts: The Illinois Department of Natural Resources, along with other agencies such as the USDA Natural Resources Conservation Service, promoted this concept in decades past. However, long-term research has shown that introducing non-native vegetation into native plant communities can have many dire consequences. This has been demonstrated by Tartarian and Amur honeysuckle and multiflora rose. Illinois biologists have not recommended non-native woody plantings for more than twenty years, and they suggest only a few non-native herbaceous plants, such as pasture grasses and legumes, for wildlife. But plenty of non-native varieties of herbaceous plants, shrubs, vines, and trees are still commercially available. Landowners should use only native plants in rural habitat projects, and where possible in backyard habitats as well. Many of our worst invasive exotic species in Illinois, purple loosestrife and garlic mustard, for example arrived here as flower or herb garden plantings and escaped "to the country" to set up permanent camp. Table 2.1 shows some of the problem species that should not be planted, even in backyards.

Even with apparently native plants, careful shopping is required. Plant scientists have made many advances in selecting and developing varieties. The results have brought us "super" varieties of many native species. Switchgrass, a native Illinois prairie grass, is a good example. This grass has proven to be good forage for cattle, and plant scientists have developed more aggressive varieties to improve production. When an improved variety of switchgrass is planted with other native prairie plants, it usually takes over and crowds out the companion species during the first few years.

Problems can arise when landowners buy species that are native to Illinois but whose seed is collected elsewhere. Many landowners shop by mail to save money on prairie plants and seed. It is always better to purchase plants and plant seed derived from stock grown in Illinois. This practice keeps local genetic diversity intact.

Myth: There are too many predators.

Facts: When people think of predators, animals such as foxes, coyotes, bobcats, and hawks usually come to mind. Yet many other species are also "predators." Herons are predators of fish, salamanders eat worms, shrews sometimes feed on other rodents, and bluebirds and robins consume beetles, spiders, and other invertebrates. Whatever the species, any wild predator will only increase in proportion to the amount of available prey.

There are two Illinois predators, though, whose abundance doesn't vary with fluctuating prey populations. These animals have increased dramatically in the last several decades, and their disproportionately high numbers on the Illinois landscape are seriously threatening the natural stability of many ecosystems. These "new" non-native predators are domestic dogs and cats. As our human population grows and expands into rural areas, pets have become a dominant force on the land. Unfortunately, their overabundance is impacting some birds, mammals, reptiles, and amphibians. Cats in particular, will hunt whether or not they're hungry. So keeping a pet well fed cannot solve the problem. When possible, landowners should confine pets to a . yard area, and put bells on their collars to alert wildlife to approaching danger. Other measures include having pets neutered and controlling the dumping of unwanted animals.

 
     
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  • Amur honeysuckle
  • Asiatic daylily
  • Autumn olive
  • Burning bush
  • Canada thistle
  • Chinese pea-tree
  • Chinese yam
  • Climbing euonymus
  • Crown vetch
  • Dame's rocket
  • European buckthorn
  • European water milfoil
  • Garlic mustard
  • Glossy mustard
  • Janpnese honeysuckle
  • Jetbead
  • Kudzu
  • Multiflora rose
  • Musk thistle
  • Narrow-leaved cattail
  • Phragmites
  • Purple loosestrife
  • Purple vetch
  • Purple wintercreeper
  • Reed canaru grass
  • Round-leaved bittersweet
  • Russian olive
  • Silver poplar
  • Sweet clover
  • Tall fescue
  • Tartarian honeysuckle
  • Teasel
  • Tree-of-heaven
  • White mulberry
  • Winged wahoo
    *While some of these species have been commonly used for backyard landscaping and wildlife habitat, they should not be planted.
     
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Comprehensive Plan for the Illinois Nature Preserves System. Part 2: The Natural Divisions of Illinois. J. E. Schwegman. 1973. Illinois Nature Preserves Commission.

Illinois Habitat Posters. [Full-color posters that depict Illinois habitats and the organisms that inhabit them.] Illinois Natural History Survey.

Illinois Wilds. M. R. Jeffords, S. L. Post, and K. R. Robertson. 1995. Phoenix Publishing, Urbana, IL.

Illinois Wildlife and Nature Viewing Guide. M. K. J. Murphy and J. W. Mellon. 1997. Illinois Department of Natural Resources.

Technical Reports on Bioregional Resources of Illinois. [Series covers 21 bioregions of the state.] Illinois Department of Natural Resources.

The Audubon Society Nature Guides. [A series of guides published by Knopf and divided by ecosystem: grasslands, wetlands, eastern forests.]

 
     
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For more information about the Illinois Conservation Wildlife Plan, please contact:

Jeff Walk
Comprehensive Wildlife Conservation Plan Coordinator
Illinois Department of Natural Resources - Office of Resource Conservation
One Natural Resources Way
Springfield, Illinois 62702-1271
Telephone: 217-783-6384
FAX: 217-785-2438
Email:

 
Illinois Department of Natural Resources, Office of Resource Conservation    One Natural Resources Way Springfield, IL 62702-1271