There are several threats(eg intensive mechanization, commercialization, and siltation, etc) to biodiversity among them deforestation, the introduction and expansion of alien and invasive species, climate change is the major one.
Since the industrial revolution, human activities have increasingly destroyed and degraded forests, grasslands, wetlands, and other important ecosystems, threatening human well-being.
Agriculture, including expansion or intensification of crop or livestock farming, plantations, and aquaculture are the most frequently identified threat to plants in IUCN Red List assessments
Causes of biodiversity loss?
The following are the major causes of biodiversity loss, they are :
Loss of habitat
Continuous loss of habitat of any particular area means there is a loss of biodiversity and the causes of habitat loss are:
- Expansion of cultivation
- Development of infrastructure
- The planned conversion of forest land
Degradation of Habitat
The degradation of forest habitats is a major threat to biodiversity. The world bank(2008) estimated that one-quarter of Nepal’s forest is heavily degraded, which has led to the loss of biodiversity, increased landslides, and soil erosion.
Following are the major causes of forest habitat degradation:
- Unsustainable overharvesting
- Uncontrolled forest fire
Poaching and illegal wildlife trade
Illegal hunting and trade of important wildlife species are major problems in the management of protected area biodiversity, The threat is particularly severe for some vertebrates driven particularly by demand for wildlife
products in international markets.
The common use of the geographical areas by humans and wildlife creates Human-wildlife conflict. Due to scarcity of food, wildlife enters human settlement and either injure or gets injured by humans which is not a good indication from a biodiversity point of view.
Invasion by Alien species:
Invasive species affect native species through predation, competition, and habitat modification. Invasion and rapid expansion of some alien species, such as Mikenia micarantha, Agerantina adenophora, Chromolaena odorata and Lantana camera has emerged as a major threat to forest biodiversity.
Stone, Gravel, and sand mining:
Excessive extraction of boulders, gravel, and sand from rivers and streams is a localized cause of deforestation in some areas, which has posed a direct threat to biodiversity. Some other causes are:
- Climate change
- Lack of awareness & insufficient public support
- Lack of data
- Inadequate Institutional Framework and Capabilities: Poor Inter-agency Co ordination, Limited resources (human and financial)
- Inadequate political commitment
- The unscientific trend of constructing infrastructure (no EIA IEE).
Consequences of biodiversity loss
- Inadequate habitat components (habitat loss)
- Competition (limiting factors)
- Seasonal migration (limiting factors)
- Behavior change: Niche adjustment and partitioning (habitat loss, degradation and fragmentation)
- Adaptation or local extinction of species (Habitat encroachment by invasive)
- Change in water and nutrient cycle (climate change)
- Invasive encroachment (edge effect)
- Change in population structure (overexploitation)
- Not all individuals in a population are equally susceptible, their vulnerability may be influenced by their size, age, sex, and genetic composition
- Disease due to lack of nutritional food (preferred)
- Inbreeding (island population).
Loss of biodiversity
Living Planet Report, published by the WWF, is an indicator of the state of the world’s ecosystems.
- Biodiversity is declining at different rates in different places
- Average 68% decrease in population sizes of mammals, birds, amphibians, reptiles, and fish between 1970 and 2016.
- 94% decline in the tropical sub-regions of the Americas is the largest fall observed in any part of the world.
- we are overusing the Earth’s bio-capacity by at least 56%, to feed and fuel our 21st-century lifestyles.
- 75% of the Earth’s ice-free land surface has already been significantly altered, and most of the oceans are polluted.
- More than 85% of the area of wetlands has been lost
Loss of biodiversity should be minimized for conservation biology. We have different efforts to counteract with loss of biodiversity and some are listed as
- Government restrictions and policies
- Protection of species
- Protection of habitats
- Stop deforestation
- Prevent overhunting & overfishing
- Prevent species invasion
- Prevent pollution
- Stop over-exploitation of resources
- Save energy
- Stop over-consumption
- Convince others