Wildlife Habitat

Wildlife Indicators :: Animal Diversity :: At-risk species :: Breeding bird survey :: Significant Natural Heritage Areas
Landscape Habitat/Indicator Guilds :: Biodiversity and Wildlife Habitat Assessment

The six-county Triangle region is home to a wide variety of plant and animal species. These include over 40 mammals, 117 birds, 50 reptiles and 39 amphibians. The region has a total of 34 state listed species, 8 federally endangered species and 33 federal species of concern. This section will address the importance of biodiversity and offer indicators to monitor the amount of high-quality habitat, the number of threatened and endangered species in the region, and a way to use annual Breeding Bird Survey data to monitor bird populations in the region.

We selected the following indicators to measure the state of wildlife in the Triangle:

Painted turtle - photos by Steve Allen
Northern water snake
White-breasted nuthatch


Biodiversity is the full spectrum of life forms and the ecological processes that support them. In the Triangle, conserving biodiversity, means protecting and maintaining a healthy patchwork of ecosystems—such as forests, grasslands, wetlands, and streams. Biodiversity usually is considered at three different levels: genetic diversity, species diversity, and ecosystem diversity.
Genetic diversity refers to the variability of genes within a species and variations among distinct populations of the same species.
Species diversity refers to the variety of plant and animal species and can be measured in a number of ways. Species richness and abundance and taxonomic diversity are the most common ways to measure species diversity. Species richness refers to the number of species found in a defined area. Species abundance measures the relative numbers among species in a defined area. Taxonomic diversity considers the genetic relationships among species. Different measures of diversity among species reflect the variety of characteristics and evolutionary relationships. Ecosystem diversity refers to the broad differences between ecosystem types, and variety of habitats and natural processes such as water flow.

Forests, meadows, and wetlands are examples of important ecosystems in the Triangle. The more types of habitat present, the greater number of species present, i.e. more species diversity. Aside from their role in supporting the Triangle’s wildlife, healthy ecosystems provide many other public benefits, including watershed protection, recreational opportunities, raw materials such as wood, climate control, carbon sequestration, and aesthetically pleasing landscapes.

Triangle Land Conservancy on the Public Benefits of Wildlife Habitat

Natural areas and well-managed forests support healthy ecosystems and biodiversity in our region. Wildlife habitat balances our built environment and provides opportunities for scientific research and educational experiences. Human activities are disrupting wildlife habitat and unalterably changing the natural world that we depend on for food, air, and water.

Triangle Land Conservancy envisions a Triangle region in which verdant habitat and healthy ecosystems support a wide diversity of native plant and animal populations.

Triangle Land Conservancy will support wildlife habitat by:

- identifying and conserving important natural areas and managed forests
- requiring conservation plans on all privately owned natural areas and managed forests conserved by TLC, and encouraging other private landowners to manage their land likewise
- ensuring that scientists and educators have access to natural areas for learning.

Why is biodiversity important?

Human life depends on biodiversity. Biodiversity maintains ecosystems and these ecosystems provide various services to maintain life on earth. Our well-being is directly linked to ecosystem services, such as the provision of clean water, fresh air and food from the land. There are also intrinsic values attributed to biodiversity from the perspective of many ethical, religious, and cultural points of view.

Healthy functioning ecosystems provide these vital services to residents of the Triangle:
  • Provisioning services: products obtained from ecosystems include food, fresh water, fuel, genetic resources;
  • Regulating services: benefits obtained from the regulation of ecosystem processes, include climate and disease regulation, water purification;
  • Cultural services: non-material benefits such as spiritual and religious, aesthetic, inspirational; and
  • Supporting services: services necessary for the production of all of the above, for example soil formation, nutrient cycling.
We rely on biodiversity in our daily lives, often without realizing it. Due to complex interrelationships between biodiversity and ecosystems, changes in biodiversity can influence many services of an ecosystem. For one example, see sidebar on a keystone species. Biological diversity can be difficult to measure directly. As an alternative, the number of species whose survival is at risk provides an indicator of changes in biological diversity, and therefore changes in ecosystem health.

Measuring Biodiversity

The Natural Heritage Program documents the occurrence and status of rare plants and animals in North Carolina and also documents the best examples of the more than 100 natural community types in the state. All six of the Triangle counties have completed Natural Heritage county inventories.. Local governments in the Triangle are able to use the inventories as guidance in balancing the need for growth with the need for natural area protection. The inventories also contain management and protection recommendations for the significant natural heritage sites in each county.

Losing ground

Most ecosystems in the world are experiencing biodiversity loss that can be attributed to human expansion.
As the Triangle region develops, some last known instances of species of concern like the Bog Spicebush (left), or Michaux’s Sumac in Wake County, have been paved over to make room for the Northern Wake Expressway.
The draining of the New Hope bottomlands in Chatham County destroyed the last known habitat for black bears that resided in the Triangle. Black bears require large home ranges and are now only infrequent visitors throughout the Triangle.

Photo courtesy of Jeffrey Pippen

Threats to biodiversity

The most significant threats to biodiversity in the Triangle are habitat loss and degradation., due to pollution, habitat fragmentation or elimination, and the introduction of nonnative “exotic” species. In the Triangle, these threats are driven by human influences, primarily rapid urbanization and poorly planned development.

Development:: Vegetative communities change naturally over time, but human influences have a dramatic impact. Urban development patterns greatly affect habitat quantity and quality and, therefore, wildlife diversity and population stability. An obvious impact on biodiversity is the loss of habitat due to conversion of forests, wetlands and agricultural lands to other uses. Infrastructure to service new developments — sewer and water, roads, power lines, telecommunications towers/lines, etc.—can also cause serious wildlife impacts by the loss or fragmentation of habitats, obstruction of migration routes and increased human activity which disrupts normal wildlife behavior patterns. The transition area between developed landscapes and natural habitats can be the source of negative effects that may limit biodiversity.

Fragmentation:: Traditional subdivision design and sprawling land use patterns can fragment wildlife habitat and cut off potential wildlife corridors. An edge effect usually occurs for some distance into a forest ecosystem that borders developed landscapes. While many species depend on the open habitat found at the forest’s edge, newly created forest openings may result in a loss of forest interior species that are not adapted to the edge. An especially serious negative effect of deforestation may occur when "forest interior" bird species are increasingly exposed to nest predators such as cats, raccoons, jays, and crows. Alternatively, environmentally friendly land use planning can benefit both people and wildlife. Requiring the conservation of open space in new subdivisions and linking open space to existing greenways and protected areas can minimize the impact of new development on wildlife. In addition, nature friendly land use planning can benefit developers and homeowners with increased home prices and faster sale rates compared to traditional subdivisions.

Invasive species:: Non-native invasive species including plant, animal, pathogen, and fungi compete with native species in the Triangle’s ecosystems. Non-natives are characterized by fast growth rates and reductions in natural predators to control their populations. As such, invasive species may out-compete native species and disrupt natural ecosystems. There are 164 non-native invasive species in Wake County alone.

Fire suppression:: Historically, fire was a natural disturbance process which shaped the composition and structure of forests. Certain species developed fire dependence while other species developed adaptations to survive frequent fire. Fire can actually increase biodiversity by reducing the build-up of natural fuels such as dry leaves, woody debris, and flammable shrubs, by cycling nutrients, and reducing invasion of non-native exotic species, offering native vegetation the opportunity to thrive in the understory clearing. Understanding the importance of fire and natural disturbance among natural communities will be imperative to understand the long term impact of fire suppression on the natural diversity in our forests.

Global change:: Global climatic warming caused by release of greenhouse gases into the atmosphere may lead to reductions in biodiversity. Native species with low genetic diversity and/or migratory ability; species and ecosystems existing in areas fragmented by human development activities could suffer pronounced negative effects of climatic warming.


A vine with a deadly twist

Japanese honeysuckle, like many invasive species, has few natural enemies which allows the plant to flourish and out-compete native plants. The honeysuckle vine can kill young trees by twisting tightly around stems and trunks, which cuts off the plant’s flow of water. Carolina Jessamine is a native alternative to the invasive Japanese honeysuckle.

Number of invasive plants by county
Chatham 111 :: Durham 164 :: Johnston 96 :: Lee 106 :: Orange 221 :: Wake 164

Photo courtesy of Jeffrey Pippen

Authors Steve Allen, Jessica Stocking and Amanda Willis :: N.C. State University :: 2010.05.07

Jacquelyn Wallace :: North Carolina Wildlife Resources Commission
Dr. Dean L. Urban :: Duke University
Dr. Christopher Moorman :: N.C. State University

Indicators:: Animal Diversity :: At-risk species :: Breeding bird survey :: Significant Natural Heritage Areas
Landscape Habitat/Indicator Guilds :: Biodiversity and Wildlife Habitat Assessment