What is habitat fragmentation?
Habitat fragmentation is the process during which a large expanse of habitat is transformed into smaller patches that are usually separated from each other.
When a habitat becomes fragmented, the ratio of edge to interior habitat increases. In this illustration, the total area of habitat is the same in both panels:
What causes habitat fragmentation?
Habitat fragmentation is caused by land conversion - when land in a natural state is transformed for new uses and purposes. Land conversion usually results from development - the expansion of human activities and infrastructure, which result in deforestation.
For example, trees and forests are cut down to make space for agriculture, housing, roads, or mining. So, the land is converted from natural forests to pastures, roads, houses, or mining sites.
How does habitat fragmentation affect biodiversity?
Different species are connected through many processes, cycles, and systems. For example, some species depend on each other because they are embedded in the same food web.
Habitat fragmentation forces individuals belonging to the same food web to be separated into small habitat fragments. So, individuals from large, contiguous populations are divided into small, local populations.
As a result, habitats, and the species and ecosystems within them, are no longer connected. The interactions within and between species are disrupted. As individuals are separated, changes in predators and prey can lead to biodiversity loss, and in extreme cases, even extinction. In addition, this process may interrupt natural cycles, which can also contribute to biodiversity loss.
Habitat fragmentation decreases the size of habitats, as natural lands are transformed and replaced by development and other human activities.
As species are forced to live in smaller and separate habitat fragments, they may have less access to the resources they need to survive. This can lead to even more biodiversity loss if species lose access to resources such as food and shelter.
Why is habitat connectivity important in developed areas?
Even though development results in habitat fragmentation, it is still possible to reconnect habitats that have been separated.
It is important to make sure that habitat fragments are connected so that species can move between them. Species naturally need to move between places for survival, so we must make sure that they can still do so even after development has taken place.
This means that conservation efforts cannot simply focus on protecting habitat fragments individually, and that the movement between fragments also needs to be considered.
The most common way to accomplish this is through the creation of biological corridors - areas of habitat used to connect wildlife populations that have been separated by human activities or structures. Corridors allow wildlife to pass more safely between the patches of fragmented habitat.
Why does this matter?
Understanding the relationship between development and biodiversity is key to finding a balance between human and environmental needs. It is only through this balance that sustainable development can be achieved, so the rights of both current and future generations are protected!
We, at the Wildlife Conservation Association, are dedicated to continue helping our community find this essential balance.
Our biodiversity monitoring program engages the local community in scientific research to learn more about local wildlife and our relationship with nature so we can reduce our impact and reach our vision of a planet in balance.
References
Food and Agriculture Organization of the United Nations (FAO). Sustainable development and challenging deforestation in the Brazilian Amazon: the good, the bad and the ugly. Adapted from a paper presented at the symposium “Our Common Ground: Innovations in Land Use Decision-Making”, 8–9 May 2007, Vancouver, Canada. http://www.fao.org/3/i0440e/i0440e03.htm
Canadian Centre for Translational Ecology. https://ccte.ca/resources/fig5.1.html
International Union for the Conservation of Nature (IUCN). Guidelines for conserving connectivity through ecological networks and corridors. https://portals.iucn.org/library/node/49061
Fahrig, Lenore. (2003). Effects of Habitat Fragmentation on Biodiversity. Annu Rev
Ecol Evol Syst 34: 487-515. Annual Review of Ecology, Evolution, and Systematics. 34.
487-515. 10.1146/annurev.ecolsys.34.011802.132419.
Schmitz, O. (2007). Ecology and Ecosystem Conservation [PDF]. Washington: Island Press.
Andrew Bennet. Linkages in the Landscape; The Role of Corridors and Connectivity in Wildlife Conservation.
Robert Northrop. Institute of Food and Agricultural Sciences, University of Florida. Urban Natural Areas #2 – Habitat Fragmentation. 16 Dec 2019 Blog. Available at