Reason 1 for Biodiversity loss: Changes in land and sea use, including habitat loss and degradation

Humans have altered over 75% of all ice-free land on earth. The two ways this has been done using are:

• Habitat Fragmentation
  • Habitat Fragmentation is the breaking and scattering of habitats into several pieces. For example, dividing a forest by building a railway track means that wildlife on one side cannot communicate with wildlife on the other. 
  • This could lead to serious damage, especially during the breeding season. Males on one side cannot access females on the other, leading to a lower reproductive rate, which results in slow decline of the population of the animal in that area.
  • Some animals may try to cross the railway track, only to get crushed to death by an upcoming train.
  • Another good example would be that of a big cat. A feline like a tiger, has a territory which may consist of several hundreds of forests. Most of these forests were once part of a single big forest, which the tiger may have travelled easily across. But as humans began clearing forests and settling down, it divides the forest into many fragments.
  • The tiger trying to move from one fragment to another, may get killed due to starvation, attacks by frightened humans, etc. This leads to a slow decline for tigers. 
  • Sparrows used to reside in villages. But as more and more villages kept turning into metropolitan cities, they have started getting scattered. Small populations of 5-10 sparrows may be found in each area, leading to a lower breeding rate and thus their decline.
• Habitat Loss and Changes in Land and Sea Use
  • Habitat loss is the complete destruction of habitats of any given species. For example, logging in the amazons may lead to the local extinction of certain species like monkeys and tapirs, which in turn leads to lesser prey for carnivores like the jaguar, As the population of jaguars declines, the ecosystem collapses, as without a carnivore, the habitat is as good as gone. Habitat loss just doesn’t cause the extinction of one species- It causes an entire ecosystem to collapse and hundreds of species are left without safe refuge.
  • Changes in land and sea use usually always lead to habitat loss. Usually, changes are made to permit companies to drill for resources or clear areas for settlements. This leads to disturbance of the habitat, and eventually results in the complete degradation of the habitat

Image Credits
Featured Image: Coal mining in Alaska By John E. Thwaites – John E. Thwaites Photographs of Alaska, Public Domain, https://commons.wikimedia.org/w/index.php?curid=52559141
Soil erosion and landslides: Vibhav Peri