Major threats to Biodiversity

The "biodiversity crisis" is a phrase the describes the rapid loss of plants and animals on the full spectrum of geographic scales.  While there have been periods of massive extinction in the past, the current loss of species is occuring at an unparalleled rate and is being caused largely (if not exclusively) by human activities. There are six generally recognized major threats to biodivsity: Habitat Loss & Degradation, Introduced Invasive Species, Unsustainable Use, Environmental Pollution, Disease & Parasitism, and Global Climate Change.  We give a brief explanation of each below. Each of these threats impacts our native flora and fauna within Indiana and habitats throughout the world.

Habitat loss

This is the world’s number one threat to biodiversity.  Species of plants and animals are declining at alarming rates.  Sustaining natural habitats is crucial to the survival and continued growth of many species of plants as well as animals.  It seems the increase in human populations along with consumption of resources by practices like logging, mining, corporate farming, and transportation are a few forces behind habitat loss and fragmentation.  For example, in Indiana the Running Buffalo Clover and the Indiana Bat hold an endangered species status, which in both cases is due to habitat loss.  Keep in mind that losing the habitat altogether can have the same adverse affects as fragmentation.  For more information on the causes and effects of habitat loss and fragmentation in the United States, feel free to visit:

http://www.sierraclub.org/habitat/ and http://www.estuaries.org/threats.html.

Introduced invasive species

This is the second most important threat to biodiversity.  Increases in human populations as well as human mobility have resulted in invasion by nonnative species.  Invasive species not only threaten biodiversity, but also threaten the whole ecosystem function.  These species have contributed to the decline of 42% of U.S. endangered and threatened species.  They may have been purposely or accidentally introduced or in some cases may have migrated there themselves.  They have no natural enemies so they are able to spread and multiply quickly.  Invasive species have a negative impact on native species by competing with them, eating them, mating with them, or even by introducing parasites or pathogens that may kill them.  This means they decrease the amount of native as well as rare species in the area they inhabit.  Some examples of invasive species in Indiana include:  garlic mustard, oriental bittersweet, Canada-thistle, Japanese Honeysuckle, and Eurasian spruce beetle.  Additional information on this topic can be found at:

 http://www.americanlands.org/forestweb/invasive.htm and http://www.fw.umn.edu/nresexotics3001/relatedlinks.html.

Unsustainable Use

This happens in an area where animals are hunted out to extinction.  Some examples of this in the past are the passenger pigeons and the dodo birds.  In Indiana, we frequently hunt for more common game, such as deer.  This tends not to be an issue of great focus in the conservation of Indiana, but if practices remain the way that they are it could become of great concern in the future.  For more information:

http://www.iucn.org/bil/unsustain.html

Environmental Pollution

This is a prevalent threat to biodiversity, and one in which anthropogenic changes within an environment can be of great concern.  Because of the large amounts of agriculture in Indiana, DDT run off has been a problem of the past, and many pesticides continue to remain a constant threat to the physical environment of Indiana.  Development of land in any way by humans often leads to pollution, and this is a problem which knows no political boundaries, and thus one that Indiana has not been able to escape.  More information can be found at:

http://www.pollution.com

Disease and parasitism

These declines may occur on a species of healthy individuals or a species either with a pollution-hindered immune systems or otherwise weakened by poor environment. While weakened species are more vulnerable to diseases and parasites already in the plant or creature's ecosystem, invading exotic species can act as parasites on otherwise healthy native species. Examples of diseases include chestnut blight and Dutch elm disease, which ravage nonresistant native trees.  For more information go to:

http://www.riverdeep.net/current/2000/02/front.030200.eid.jhtml

Changes in global climate

This is seen as elevated temperatures, which cause shifts in suitable habitat and changes in global rainfall. Examples of shifts in hospitable habitats include the mountains of Costa Rica, where tree frogs move continuously upslope toward the cooler environments for which they are adapted, and, more locally, in Indiana's caves, where warmer temperatures increase the metabolism and therefore starve hibernating Indiana bats. Warmer temperatures cause earlier snowmelts, which cause higher water levels in winter and spring and lower water levels in summer. Thus, elevated temperatures leave less water available during the height of summer. Indiana's hardwood forests would be replaced by drought-resistant conifers and quick-growing brush trees. Also, reptiles with temperature-dependant sex determination, including alligators, design nests so as to produce equal parts male and female offspring under normal temperatures. When temperatures rise, the same nest would produce more of one gender. More discussion of ecosystem effects is at:

http://www.epa.gov/globalwarming/impacts/stateimp/indiana/