What is habitat?
Habitat is where an animal lives. In reality, however, the concept of habitat is more complex. No two species are exactly the same, and varying life histories and ecology lead to specific and often very different habitat needs. But no matter the species, habitats consist of four basic components: food, water, shelter and space. These are the four main aspects you should focus on if you want to attract and sustain wildlife on your property.
One way to categorize wildlife species is by what they eat, and food is often a good place to start if you want to attract certain species to your property. The major dietary categories include:
Mostly eat insects
e.g. Tree swallows, many warbler species, frogs and most bat species
Water, like food, is physiologically crucial to wildlife. In fact, in many ways water is even more critical than food for an animal’s survival as most animals can go longer without food than water.
How do animals get water?
- They drink water. Available drinking water is especially important to species that eat very dry foods (i.e. granivores), as their food contains very little water.
- From their diet. Carnivores, for instance, may not need to drink water at all if their prey is significantly moist enough.
- Metabolically. Species that live in hot and arid environments, like deserts, can satisfy their need for water by breaking down food components like fats, proteins, and carbohydrates during the digestive process, thereby producing water.
Other benefits of water
Water can also be a space for wildlife to live, nest and find food. Animals like beavers, otters and waterfowl use bodies of water as shelter and protection from predators. Others rely on water resources to complete their life cycles. Frogs and other amphibians, for example, lay eggs in water. Many bird species like ducks and herons rely on water to provide food in the form of plants and algae, invertebrates and fish.
Animals need shelter for several reasons: to sleep, to hide, to raise young or to take shelter from unfavorable weather conditions. Exposure to the elements can be just as dangerous as predators under certain conditions. Shelters may be as basic as the lee of a tree during a storm, or as elaborate as an underground burrow system.
A few points to consider about food, water and shelter
- A species’ food, water and shelter requirements can change over time. An animal that is breeding and raising young will have different needs than when it is trying to survive the winter. Additionally, migratory birds may use stopover habitat to rest and refuel. Though some birds might only visit your property twice a year (once going north and once going south), the habitat you offer may be critical to that species and make the difference between a successful or not successful migration.
- The more year-round habitat you can provide, the more an animal will use your property. This is especially important in northern climates where food sources may be scarce. For example, the end of the winter and beginning of spring are times of the year when food may be the least available because animals have exhausted their food sources to get through the winter, but new growth has not yet started.
- Food, water, and shelter need to be relatively close together to be beneficial to the wildlife you’re trying to attract. Keep in mind, the smaller the animal, the smaller the area it will occupy.
- Food, water and shelter can all be provided naturally, supplementally, or both. Natural sources are those that are already available, such as acorns from an oak tree, water from a stream or shelter in an old tree cavity. Supplemental sources are provided by humans. These commonly include bird feeders and houses and artificial ponds.
Of the four basic components of habitat, space is by far the most predetermined and defined. Property boundaries are typically known and unmovable. Despite this, depending on the quality and quantity of habitat contained within, your space may be highly influential in determining how wildlife is distributed across the landscape.
How do we consider space?
- First, let’s talk about size. Generally, a larger-bodied species will need more space than a smaller-bodied species, and territorial species will need more room per animal than non-territorial species. Given these examples, there may be some species that you simply won’t be able to attract to your yard if their space requirements exceed what you have available.
- The composition of your space also plays a role in determining which species are present. If adequate food, water and shelter aren’t available in sufficient amounts or are spaced too far apart, you may not attract your desired species, despite having each main component present.
- The greater the habitat diversity contained in your space, the greater your potential for attracting a diversity of wildlife. One way to promote habitat diversity is to manage for edge habitat, areas where two or more vegetative communities meet (i.e. forest and grassland). You can also create edge habitat between different age classes of the same plant community (i.e. a 15-year-old oak forest adjacent to a 45-year-old oak forest). Because edge habitat is common where landscape fragmentation is prevalent, it is usually already abundant in urban areas.
- Alternatively, because edge habitat is so common in urban areas, you may choose to manage for a more contiguous habitat on your property. Contiguous habitat is similar throughout and distributed continuously across your property and perhaps between properties. Contiguous habitat is beneficial to species that require a large “interior habitat,” which can be generally defined as the core of the habitat, buffered from edge habitat. Interior habitat can be difficult to create in urban areas, but properties adjacent to parks or other natural areas can be good candidates for creating and managing interior habitat.
A few thoughts on space
- Collaborating with your neighbors can be a great addition to managing your own property. You and your neighbors may choose to create, enhance and manage similar habitats, creating larger blocks of habitat than any one property owner could on their own. It can also be more fun to work together, and it may make it possible to undertake larger scale projects and allow for saving on materials by buying in bulk.
- You can view an aerial map (i.e. Google Maps using the “Earth” view) of your property to help you understand how your property fits into the larger regional landscape. Rather than creating and managing habitat that doesn’t fit into the larger landscape context, consider creating similar habitat and expanding on the habitat already available in the region. Your property may become a useful stepping stone to help wildlife move between larger blocks of habitat (for example, a nature preserve or wildlife management area) that are nearby.
Decoding Urban and Suburban
Urban areas are locations with extremely dense human populations and supporting infrastructure.
According to the US Census Bureau (2012), there are two types of urban areas:
- Urbanized areas contain 50,000 or more people.
- Urban clusters have at least 2,500 and less than 50,000 people.
- The spatial size of urban areas or clusters varies widely but generally follows municipal boundaries.
Urban areas can also be distinguished based on their complex infrastructure:
- The majority of buildings are multi-story and multi-purpose, providing housing for city residents and locations for businesses.
- Much of the land between buildings is designated for roads, parking lots and sidewalks, facilitating movement into, out of and within the city for the human population. While impervious surfaces support urban transportation, they don’t support native habitat for wildlife.
- Green spaces are mostly limited to city parks interspersed within urban limits and perhaps rooftop gardens and green roofs.
Suburban areas surround the city, and unlike urban areas, there is no human population-based definition for suburban areas. To paraphrase Supreme Court Justice Potter Stewart, “I can’t define suburban, but I know it when I see it”. Suburban areas typically feature:
- Horizontal growth (i.e., sprawl)
- Residential living, business and industrial districts and parks separated into distinct areas based on zoning regulations
- Larger homes with more green space (gardens and front and back yards) relative to urban areas
- A fragmented landscape containing impervious surfaces like roads, parking lots and sidewalks, but at a lower concentration than urban areas