When a forest becomes fragmented, trees of many species are isolated because their pollinators cannot cross the unforested areas. Herbicides blow from cleared agricultural areas into forests, and exotic species introduced by farmers and ranchers spread, often displacing native species.
Without further stress, Causes of recent declines in biodiversity forest may regenerate. Asian tropical freshwater turtles are in serious decline because they are extensively hunted for food or for use in traditional Chinese medicines.
Earlier this animal was found in Tarai regions of Uttar Pradesh, Assam and Bengal but now confined to only one or two pockets of country. The Alagoas curassow, a large fruit-eating bird of this area, is now extinct; many others toucans, aracaris, guans are endangered by hunting pressures.
The migratory patterns of some birds which live in both tropical and temperate regions during the year seem to be shifting, which is dangerous for these species, as they may arrive at their breeding or wintering grounds at an inappropriate time.
There is recent evidence that climate changes are having effects on tropical forest ecology.
This has led to increased pressure on agricultural land for exchange commodities and export goods. Presently, remaining forest cover is under severe pressure particularly in Himalaya, Central Indian uplands and Western Ghats.
Intensive hunting, by depleting animal populations, inhibits plant reproduction, since many seeds can neither be dispersed, nor flowers be pollinated without them. In Brazil, three to seven times as many Heliconia acuminata seedlings planted in continuous areas of forest germinated as compared to those planted in fragmented areas Bruna, Development and utilization of various forms of energy resources, e.
This could affect interaction with other species that depend on flowering plants. The mortality of trees in fragmented patches in Brazil has been found to be twice that of similar trees in the forest interior Laurance, et al.
Habitat destruction and fragmentation are considered as prime reasons of the biodiversity loss and is generally called the deforestation. Many of these animals, or their parts, are smuggled illegally from Southeast Asian and other countries to China and other countries with large Chinese populations for these uses.
It can mean that biodiversity has been harmed, rather than lost altogether. The geometric rise in human population levels during the twentieth century is the fundamental cause of the loss of biodiversity. Animals, particularly large ones, cannot maintain themselves in small fragmented forests.
These effects can be seen as far as one kilometer into the forest. These introduced species may displace native species through competition for limited natural resources; they may push them on the verge of extinction or they may alter the habitat so that many native species are no longer able to persist.
These exotic organisms interrupt the forest ecosystem and, since they have few or no natural enemies in their new environment, they are difficult to eradicate. Such unsustainable fishing operations have led and are leading to severe declines in fish in major river systems within tropical rainforests see the case of the tambaqui, Part II, F3, b, ia.
The drier and warmer conditions also make the fragment more flammable, with a concomitant increase in the frequency of fires. Climate will probably change least in tropical regions, and nitrogen problems are not as important because growth in rainforests is usually limited more by low phosphorus levels than by nitrogen insufficiency.
Inthe results were published of the first worldwide assessment of amphibian populations, the Global Amphibian Assessment. The cartilage is stained blue and calcified bones in red.
Under these conditions, the trees in the fragments will then become inbred and lose genetic variability and vigor. Altogether population has increased by three times and is expected to increase upto 1, million bywhich would further increase the pressure on biodiversity.
Humans have drastically disturbed the natural rate of extinction of species and speciation Leemans, Eventually fragments may disappear altogether or undergo ecological collapse. Many effects are consequent upon this. Fragments are much more easily accessible to human incursions than are intact forests.
While UVB radiation is an important stressor for amphibians,  its effect on the egg stage may have been overstated.
There are apparently no turtles left in the wild in Vietnam for this reason Gibbons, et al. These features include genetic diversity, within and among species; ecosystem connectivity, a term that refers to the amount of intact habitat available to plants and animals; and widespread geographical distribution of populations.
The changes in mists appear to be a consequence of warming trends.
Altogether, India has recorded increase in net forest cover in recent past but natural forests have decreased.
On the other hand, a number of instances of amphibian decline seem to be due to infections with chrytid fungi, which flourish at cooler temperatures.Understanding the causes of biodiversity loss and the policy assessment framework 3 Table of contents Table of contents 3 List of Figures 7.
Rainforest Conservation Fund: Causes of recent declines in biodiversity; About the Author.
Based in Vancouver, Kirsten Campbell has been a professional ecologist since She has worked with various governmental agencies and in the private sector. Campbell holds a Master of Science in ecology and conservation. Davidsonia 47 Some Causes and Consequences of the Loss of Biodiversity: Ten Years of Plant Ecological Research in the Yukon Abstract This article introduces the new Biodiversity Research Centre at UBC and reviews the.
In a developing country like India, the patterns and causes of habitat destruction, which is a prime cause of biodiversity loss, are linked to ever-increasing pressure of human population together with their domestic animals, associated with other developmental activities for the better living of mankind.
Causes of recent declines in biodiversity The major causes of biodiversity decline are land use changes, pollution, changes in atmospheric CO2 concentrations, changes in the nitrogen cycle and acid rain, climate alterations, and the introduction of exotic species, all coincident to human population growth.
Causes of the loss of biodiversity.
The main cause of the loss of biodiversity can be attributed to the influence of human beings on the world’s ecosystem, In fact human beings have deeply altered the environment, and have modified the territory, exploiting the species directly, for example by fishing and hunting, changing the biogeochemical.Download