- December 11, 2015
To simplify the wildlife habitat category displayed on the group pages we’ve combined all the vegetatively-complex habitat polygons into one category, which includes forest, shrubbery, wetlands, grasses, and non-woody plants (a.k.a flowers and other herbs) along with other habitat polygons–water, ground, and other–that can act as important resources for a variety of wildlife from birds to pollinators to amphibians.
These habitat types can be roughly considered the source of most wildlife habitat on most sites, because they are the locations where complex vegetation can be found. We exclude lawn (green), pavement and buildings (combined into the grey band), and edibles (croplands, food gardens, and cultivated land depicted as pink) from this calculation because they rarely act as robust sources of habitat. These resources do not provide sufficient food, cover, or water to significantly contribute to many organisms’ life-cycles, and so are represented independently in the data visualization.
Taken together, landcover likely to contain complex vegetation can create a rough picture of habitat availability at a site.
For birds, natural food availability has been correlated with nesting success in urban areas open_in_new. Plant diversity that includes woody species (shrubs and trees) has been correlated with increased breeding bird diversity in Massachusetts open_in_new open_in_new and with Lepidoptera (caterpillars; an important food source for breeding birds) diversity in the mid-atlantic region open_in_new. And, in fact, plant diversity has been shown to increase biodiversity across trophic levels open_in_new. Findings like these indicate the importance of landcover that includes a variety of plant structural-types ranging from those provided by trees to those provided by herbs. The habitat types we include in this calculation are those where these kinds of complex vegetation are likely to occur or are sources of other habitat resources, like water. Taken together, they create a rough picture of habitat availability at a site.
Forest. Trees, Woods, Grove. A tract of land covered with trees and underbrush; woodland.
Forest Characteristics. You can set a forest polygon to indicate additional ecological detail including Forest Type. The kind of tree that dominates your forested area tells us a lot about the kind of birds, plants, and other wildlife you might expect to find there. Deciduous forests are those where the dominant trees lose their leaves for part of each year (either because of cold or drought), while evergreen forests are dominated by trees that keep their leaves year-round. You can also select mixed forests, with both deciduous and evergreen trees. Then set the Forest Age. Different organisms utilize forests of different ages. For instance, Golden-winged Warblers prefer disturbed, early-successional forests, while Scarlet Tanagers prefer mature forests.
You can set two characteristics related to native plants. The first, Percent Native, asks you to estimate how much of the forest is native to your region. The second, Managed for Natives, lets you indicate if you are actively managing the space to encourage native plants and exclude invasive ones. There exists extensive controversy about the role of natives and non-natives in different wild ecosystems. Some research claims that the presence of non-native species reduces the overall biodiversity of an ecosystem,open_in_new while others claim that non-natives do not contribute to decreases in biodiversity, and may, in fact be just temporary members of a plant/animal community, or a sign of normally changing ecosystem open_in_new. Methods in managing for natives vary from habitat to habitat, but in general include removing invasives and providing a source of native seeds. Managing for natives can be very complex, time-consuming, slow, and expensive, or it could simply mean that when given a choice, you favor preserving or introducing native species into your habitat. If you own large tracts of forest it might make sense to take the time to put together a formal plan to manage for natives in your area.
Similarly, you can indicate if your forest is Managed for Wildlife. Managing wetlands, grasslands, forests, and shrubbery for wildlife is a complex endeavor that usually requires forethought and planning. Much of this project is devoted to helping you think more about managing land for wildlife. Many landowners with significant tracts of land will work with local conservation biologists or outreach associates from their local cooperative extension to develop plans that fit their properties; we simply want to know if you consider your current management practices to be “for wildlife” or not at this point. To find out how to do this consider getting in contact with your local cooperative extension office (check out the Local Resources section on the Explore Page for a link to your local office). Lastly, you can set whether the forested space is harvested for timber. Many people actively manage their forests for harvest. How that wood is harvested may impact the wildlife found there open_in_new. For instance, some people spot harvest, targeting individual mature trees scattered throughout their plots. Harvesting these trees can be fairly low-impact, perhaps even beneficial to species that rely on forest openings for habitat because they mimic a natural tree fall in the woods. Clear-cutting a forest, on the other hand, increases forest fragmentation, which has a huge impact on forested birds’ survival.
Shrubbery: Brush, Chaparral, Hedge, Thicket, Scrub. A tract of woody plants that are smaller than trees, usually having several stems rather than a single trunk.
Shrubbery Characteristics. Like with the forest habitat, you can set a Shrubbery polygon to indicate additional ecological detail including Percent Native and Managed for Natives. The former lets you estimate the percent of a given shrub polygon that is native to your region. The latter lets you indicate if you are actively managing the space to encourage native plants and exclude invasives. Some research hints that the native status of shrubs in and around urban areas can dramatically impact nesting success, with non-native shrubs, like honeysuckle, acting as ecological traps by enticing birds to nest, but leaving those more vulnerable to predators open_in_new.
Also like forested areas, you can indicate if your shrubbery is Managed for Wildlife. Shrubbery also includes a characteristic to indicate whether the shrub area is Grazed or not. Whether or not there are livestock grazing a shrubby area impacts its ecological makeup by altering the composition and growth patterns of the plants found there. Read more about the grazing characteristic below, under “Grasses.”
The presence of woody plants, even in urban parcels, has been shown to increase breeding bird diversity and nesting successopen_in_new. The density, or Cover Thickness of shrubby landcover is another important landscape ecology measurement as it varies considerably across terrain. Some areas are fairly thin, covering only 10% of the ground with vegetation, while in other areas are extremely thick, covering 100% of the area with dense thicket. The percentage of that vegetative cover can affect breeding successopen_in_new.
A quick rule of thumb for estimating shrub cover is to imagine walking through the area. If you can easily walk without touching any vegetation, cover is probably less than 50%. If you have to weave around plants and often come into contact with them as you move through the space the cover is probably about 75%, and if you can’t image walking through without a machete then 100% is a good estimate.
Use the satellite imagery on the map and the diagrams above as a reference point for your estimate. For some, it helps to mentally divide up your shrubby area into a pie chart with 4 slices. Try to quantify how much of the pie would be covered by shrubs if you placed it over your shrub patch.
Read more about Shrub Habitat Here
Wetlands: Riparian, Rain Garden, Bog, Fen, Marsh, Swamp. Wetlands are areas such as swamps, bogs, and marshes where water either covers the soil or is present at or near the surface, particularly in the root zone, at least a good portion of the year, including the growing season.
Wetland Characteristics. You can set a wetlands polygon to indicate additional ecological detail including Wetland Type. Technically marsh, wetland, estuary, bog, riparian area, rain garden, fen, and swamp all have slightly different meanings. But they all describe areas where water either covers the soil or is present at or near the surface, particularly in the root zone, at least a good portion of the year (including the growing season). To figure out which kind of wetland you have, visit this Guide. Rain Gardens, are not defined at that link, but you can read about them on this project’s webpages, to help you understand if your space fits in this category.
You can also set whether the wetland area is Seasonal or not. Some wetlands, ponds, streams, and even lakes are seasonal – that is, present in wet months, but absent during the dry season. One important kind of seasonal wetland are vernal pools. Additionally, like with Shrubbery and Forest explained above, you can set Percent Native, Managed for Natives, and Managed for Wildlife for wetland spaces.
Read more about Wetland Habitats Here.
Water. Pond, River, Ocean, Stream, Lake. Any open body of water; stream, river, pond, ocean, bay, estuary, lake, or spring.
Water Characteristics. Like with the Wetland polygons you can set Water Seasonality and Water Salinity for Water polygons. In addition, you can set a Water Flow characteristic. Examples of flowing water include rivers or streams, while examples of standing water include ponds or lakes.
Read more about Water for wildlife Here.
Grasses. Meadow, Prairie. An area that is dominated by grass or grass-like vegetation. The natural vegetation should consist largely of perennial grasses. Often characteristic of sub-humid and semiarid locales.
Grasses Characteristics. Like with forest, shrubbery, and wetland habitats above, you can set characteristics for Percent Native, Managed for Natives, and Managed for Wildlife for Grasses habitat polygons. Additionally, you can indicated whether the area is Grazed. Whether or not there are livestock grazing a grassland or shrubby area impacts its ecological makeup by altering the composition and growth patterns of the plants found there. North American farmers have become de facto managers of grassland bird habitat. Because many grassland birds, such as the Bobolink, Dickcissel, and Eastern and Western Meadowlark prefer mid-range to high vegetation and soil moisture, grazing intensities and vegetation densities can impact habitat and nesting conditionsopen_in_new. For more information about using grazing for management of range and grasslands, including a date map showing how long to delay mowing, see our grasslands article. You may also indicate whether you practice Wildlife-Friendly Mowing. Some research has shown that birds attempting to nest in hay fields experience drastic nest failure due to mowingopen_in_new.
There are steps you can take to minimize the damage done to field bird populations, without completely dropping your hay harvesting. We call this wildlife-friendly mowing:
- Delay your harvest, especially if you think inclement weather might have caused delayed nesting in your area. Many birds can successfully raise their young and get them out of harm’s way by the end of June. The longer you wait, the more likely the birds are to fledge and get out of the way of your mower blades.
- Leave safety strips in your field. Instead of harvesting every inch, leave bands of unharvested grasses approximately 30 feet wide to provide a safe spot for field birds to keep out of the way. Field edges and odd areas can be targeted for exclusion as well.
- Walk your field and learn where your nests are. Don’t harvest the areas where you discover nests.
- To give birds the best chance of escaping, harvest fields by starting in the center and working outwards.
- Raise the height of your mower blades.
As an extension of Wildlife-friendly Mowing we also collect data about Hay Harvest date. Delaying your harvest could help more birds successfully nest. The later you mow, the more likely it is that nesting birds will have successfully fledged and can get out of the way of machinery. For grasses polygons you can also indicate Irrigation Frequency.
Read more about Meadow and Grass Habitat Here.
Non-woody Plants. Annuals, Perennials, Ground-cover, Flowers, Herbs, Ferns. Flowering plants whose stems above ground do not become woody. Technically grasses are herbs, but because they have their own category, please denote them as such.
Non-woody Plants Characteristics. For this habitat polygon you can set Irrigation Frequency, Percent Native, and Managed for Natives as explained above.
In addition, we let you indicate whether an area is Tended vs. Wild. Unmanaged wildscapes are very different habitat-types than heavily tended formal gardens. How “wild” your landscape is helps us understand the types of practices you are implementing in that territory to support wildlife. For instance, if you weed, irrigate, or plant in the area that makes it much less wild than a space you leave to grow however it may. Many people cultivate some areas of their yard, but let others go wild.
Read more about Non-woody plants Here.
Ground. Dirt, Sand, Gravel, Soil, Rock, Mulch. Landscape mostly bare of vegetation. Ground cover might be dirt, gravel, rock slab, or sand. Some desert areas have extensive gravelly areas. Mountain tops have bare rock.
Ground Characteristics. The only additional detail you can currently provide for ground polygons is to set the Ground Type.
The kind of ground–be it sand, rock, dirt, gravel or mulch–is an important indicator of the kinds of plants that might grow, or the potential uses of the area by different kinds of wildlife. For instance, many species of native bees require bare earth to nest in. This is an important resource for them to successfully complete their lifecycle.
Use this category when none of the others fit. Use it sparingly. Remember to read the descriptions of the other categories carefully, as they are meant to be broad. Special landscapes, like sand dunes or tundra, might justify use of this habitat type in your map.