The development of land and related activities impact both the quantity and quality of wildlife habitat. This information from the National Parks & Wildlife Service provides an overview of those impacts.
WHAT IS BIODIVERSITY AND WHY PROTECT IT?
Biodiversity means the variety of all life on earth from the smallest and simplest micro-organism to the complex system that is a rainforest. It includes the habitats and ecosystems, which support this life and how life-forms interact with each other and the rest of the environment.
Biodiversity is important because it provides a source of significant economic, environmental, health and cultural benefits. It provides us with a large amount of goods and services (such as food, medicine, raw materials and clothing) that help us to sustain life on earth. It is these goods and services that allow us to live on this planet.
The wellbeing and prosperity of earth’s ecological balance as well as human society directly depends on the extent and status of biological diversity. Businesses depend on the earth’s biological resources as essential components and services for the operation of their day-to-day activities, such as clean water and raw materials. It is therefore important that there is a sustainable supply of these resources to ensure economic growth.
However, biodiversity is constantly under threat worldwide. Activities such as increased development, inappropriate agricultural practices, poorly managed afforestation and climate change have all put pressure on biodiversity with the result that many species of plants and animals are now under threat of extinction.
It is vital, therefore that all sectors in society play their part in the protection of biodiversity.
WHAT IS HABITAT LOSS?
When land is converted from its natural state to a developed landscape it has the single greatest impact of increased human activity on native wildlife.
All animal species require certain habitat features to survive.
Land development typically eliminates or significantly changes many important habitat features found in a natural area thereby altering the ecological or habitat value of that area. For example, a diverse wildlife population depends upon the natural ecosystems found in most undeveloped areas. Development can damage or destroy these ecosystems, making it more difficult for many native species to survive. Those species able to survive in urban settings may thrive, but the rest are forced to find new territory to survive.
Where habitats and wildlife species have been identified as being of significance, special measures may be required either to avoid or minimise the loss or to mitigate for it during development processes.
WHAT IS HABITAT FRAGMENTATION?
When large tracts of the natural landscape are gradually developed and subdivided until only patches of original habitat remain. The patches are often too small and too far apart to support the survival and reproductive needs of many wildlife species during various stages of their life-cycle or in different times of the year. This results in both habitat loss and the fragmentation of the remaining parts.
When a species’ habitat is separated by such distances that make movement from one area significant and reduce a species’ ability to reproduce. In addition, fragmentation of habitats results in fewer species, even if the total amount of habitat is the same as it was originally. There is also the likelihood that animals will try to cross between two areas of habitat, which can result in animal deaths if roads and railway lines are involved. Furthermore, smaller patches of habitat and the wildlife that depend on them are more vulnerable to the effects of natural disturbances i.e. fire, flooding etc.
HOW DOES HUMAN ACTIVITY AND DEVELOPMENT IMPACT BIODIVERSITY?
The impact of human activity on biodiversity extends beyond the actual area of development into what is referred to as a “disturbance zone” i.e. the entire area where habitat value has been meaningfully reduced. The encroachment of human activity into a natural area creates changes in environmental conditions as well as changes in animal behaviour and well-being as a result of being in close proximity to the border between habitat areas.
In addition, the encroachment of human activity reduces the amount of interior habitat area relative to edge or border area. While borders between two different habitats are often an essential part of the ecology of an area, when habitat becomes so small that it is all edge and no interior, it loses its ability to support those species that require an isolated interior for some portion of their life (e.g. some nesting birds).
Other types of landscape disturbance include altering the structure of soil by compaction and adversely affecting the hydrology of a site resulting in the loss of species and changes in habitat type. Furthermore, landscape disturbance caused by development can also serve to introduce invasive species into natural habitats, further degrading the quality of remaining habitat areas.
DOES HUMAN ACTIVITY IMPACT AQUATIC HABITAT?
Development can also affect the quality and quantity of aquatic habitats. Increased amounts of hard surface can reduce the ability of rainwater to infiltrate the soil. Rainwater instead runs off the land at an increased volume and rate. This has the potential to reduce the recharge of groundwater and increase flooding, streambed erosion, and sedimentation.
Runoff from developed areas is often warmer with potential for carrying pathogens (i.e. bacteria and viruses), household chemicals, metals, fertilisers, pesticides, oil, and grease. As vegetative buffers along water bodies are lost, sunlight can further warm water beyond a threshold at which some native species can survive and reproduce.
The structural habitat of aquatic systems also can be significantly degraded by modifications associated with roads and development. The quality and flow of rivers, streams and wetlands can be reduced by inadequate or inappropriately designed culverts, creation of new dams, and channel straightening or modification. Wetland habitats can act as flood buffers, water filters and can be important habitats for many species of flora and fauna.
The amount of water and drainage present at such sites is their most important feature and increased erosion, sedimentation and ultimately a loss of habitats and species. Species such as salmon and pearl mussel are extremely sensitive and are indicative of unpolluted waters. Sedimentation or pollution events that may occur during activities such as culverting, bridge construction and even vehicular construction traffic in or around rivers/streams, can impact negatively on these species, both at the construction site and further downstream.
HOW DOES DAILY HUMAN ACTIVITY IMPACT THE ENVIRONMENT?
Human activity introduces changes to the surrounding environment that can negatively impact natural habitat.
Changes in lighting in an area, for example, can significantly affect some species’ behavioural and biological rhythms, which are guided by natural cycles of light and dark. Nocturnal species, particularly birds, can become disoriented by night-time lighting.
Domestic pets, particularly cats, may prey excessively on wildlife, such as ground-nesting birds. The availability of household rubbish can alter the composition of wildlife communities by providing food for animal populations that thrive on trash (such as rats etc.) to the detriment of those that do not, e.g. small mammals and some birds.
Human recreational activity in an area may directly impact wildlife and reduce the quality of the habitat provided. Human activities can disturb sensitive habitats and wildlife. Disturbing wildlife raises their stress level and increases energy consumption. If repeated frequently, such disturbance can impact on reproduction and the survival of the species.