continue to increase our impact on the global landscape, such as through agriculture and urban development, more and more of the landscapes across our planet are becoming fragmented. This fragmentation leaves much less quality habitat for native species, and is having many negative impacts on their ability to survive and thrive.
The following list discusses many of the biggest dangers of habitat fragmentation.
Increase of vulnerability
Some species are extremely sensitive to disturbed habitat and may not be able to adapt very well to such disturbances. This is likely to increase these species’ vulnerability to extinction.
Reduction in overall biodiversity
Because of an overall reduction in suitable habitat, some species may not survive. This inevitably results in a reduction of the biodiversity that is present in a particular area or region, especially for species that only live in one or just a few specific locations on Earth.
Habitat fragmentation can result in habitat “islands,” where individual members of a species are separated from one another and can no longer reproduce with the rest of the population. This essentially leads to a “bottleneck” of genes within the remaining population, where the genetic diversity of the species is reduced due to fewer individuals.
Reduced population numbers can also lead to inbreeding among close relatives, and the expression of negative genetic traits among the remaining individuals, such as physical deformities. This process is known as “inbreeding depression,” where the population’s ability to survive and reproduce is reduced.
A reduction in potential available mates
Individuals may be left only with mate choices that have negative traits or those that are close relatives.
An increased vulnerability to predation
As habitat becomes more fragmented, individuals may become more vulnerable to predation due increased access by predators.
Overall habitat quality diminished for species
Fragmented habitat contains much more edge than the intact habitat has. Habitat fragmentation dramatically reduces the amount of quality habitat for those species that require large tracts of undisturbed land, such as the Northern Spotted Owl (Strix occidentalis caurina) in the State of California, which requires large tracts of high quality old-growth forest for its critical habitat¹.
An increased likelihood of future habitat disturbances
Fragmented habitat often leads to even more fragmented habitat and disturbances, due an increased level of access. The remaining habitat becomes increasingly vulnerable to predators, the development of roads and infrastructure, invasion by invasive species, and increased access for humans to hunt and harvest species and natural resources that exist there, such as through mining and logging activities. In the case of invasive species, native species can be out-competed by the invasive ones, potentially threatening the survival of the natives.
Barriers to migration
Habitat fragmentation can make it difficult for some species to migrate to important habitat in order to reach seasonal food sources, mates, and reach suitable places to raise their young.
Increased vulnerability to natural disasters
As habitat becomes more fragmented, it also becomes more vulnerable to destruction from natural disasters such as flooding, hurricanes, and wildfires. Large tracts of intact habitat typically provides greater protection to many of these types of disasters than a highly fragmented landscape.
Species management becomes more difficult
When habitat becomes fragmented, it makes it more difficult for natural resource and wildlife managers to effectively manage species populations that are isolated from each other and are being subjected to greater threats and stresses.
These negative impacts of habitat fragmentation are precisely why we must maintain large tracts of undisturbed and undeveloped habitat, and reconnect existing fragments through wildlife corridors and effective habitat restoration. To maintain the remaining biodiversity of the Earth, we must preserve the natural habitat that remains, or we risk losing much of our planet’s irreplaceable natural heritage. Nature’s web of life undeniably works best when all parts are present and are working together in harmony.