The Global Decline of Amphibians and Its Relevance in Our Times
Rishin Pandit
Thomas Jefferson High School for Science & Technology
The Global Decline of Amphibians and Its Relevance in Our Times
Of all known amphibian species, 42% have experienced population decline and nearly a third are threatened with extinction (Vredenburg, 2013). Amphibian species are suffering a serious global decline. Disappearances of frogs, toads, and salamanders have been reported in North, Central, and South America, Europe, Asia, Africa, and Australia (Blaustein & Wake, 1990). Natterjack toads from western Britain experienced a 75 to 80 percent loss in population from 1900 to the early 1970s. The Negros cave frogs of the Philippines declined
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One hypothesis is that the alien species often cause declines and even extinctions of native amphibian populations. The amphibians are threatened because of predation by alien species, competition between life stages, and the introduction of pathogens by these non-natives. Another theory is that changes in land use have negative effects on biodiversity of native communities. It can facilitate local and eventually regional extinction of populations and species by killing organisms, removing habitat or preventing access of animals to breeding sites. Also, ultraviolet radiation, global warming, increased use of pesticides and other toxic chemicals, and the emerging infectious diseases are causing a significant decline in amphibian population (Collins and Storfer, 2003). Of all these hypotheses’, the salamander population decline in Appalachian region is mostly attributed to invasive species and climate change (Gratwicke, 2008). Humans should be concerned about the global amphibian decline as it directly impacts our environment. Amphibians play an important role in energy flow and nutrient cycling, and without them the entire ecosystem is destabilized. Humans also use them for medical research and development of new drugs (Collins and Storfer, 2003). Humans have the power to curtail the amphibian population decline and they should do it for their own long-term
Hyla versicolor, commonly know as the Gray Tree Frog or the Eastern Gray Tree Frog, is an amphibian that is referred to as the “Chameleon of the Frog world” (Craighead, 2004, p.1) because of its ability to change colors. “This frog was once thought to be the same species as the Cope’s Gray Tree Frog”. They can only be distinguished by their calls and the fact that the Cope Gray Tree Frog is diploid while the Gray Tree Frog is tetraploid (NPWRC, 2004). The Gray Tree Frog is classified as follows:
Man is responsible for the extinction of the North American megafauna (Donlan 2005, Rubenstein et al. 2006). Since our ancestors are responsible for the extinction, it’s our duty to fix what our ancestors have destroyed (Donlan 2005). Moreover, according to Donlan (2005) most megafauna species in Africa and Asia are endangered or under threat. Hence, relocating them to North American is a best way of conserving them because the country carries “Global conservation implications” and contrary to that Africa and Asia practice poor conservation strategies (Donlan 2005). He further argues that N...
Global change is taking place every day; therefore, it is important to understand how human activities and behavior alters the biodiversity and functions of ecosystems. Alien species is a stimulator of major changes in ecosystems (Vila et al. 2011). An invasive species, is a non-native plant, animal, or fungus that moves to a new ecosystem in a foreign environment. Invasive ecology explores how the invasive species affect the economic, environmental, and human health on the new environment. For example, invasive ecology studies how an invasive species tends to crowd out and sometimes replace a native species (Richardson and Pysek 2008).
The eradication of species numbers average at a toll close to one hundred percent of earths total living creatures. “It is the Earth's most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct” (Sahney, and Benton 759). Not only where marine and terrestrial species effected but this catastrophic event is the only recogni...
Long-term survival of a species depends on its ability to adapt to changing environmental conditions (Murphy, 1994). Genetic diversity within a species, which has taken 3.5 billion years to evolve, makes adaptations to these changing environments possible. Unfortunately, the rate of extinction of genetically diverse organisms is rapidly increasing, thus reducing this needed biodiversity, largely due to the human impacts of development and expansion. What was an average of one extinction per year before is now one extinction per hour and extinct species numbers are expected to reach approximately one million by the year 2000 (WWW site, Bio 65). As a result governmental and societal action must be taken immediately!
A different scenario takes place when an alien species is transported to a new area. Although direct competition with similar species is still a problem, the new kid in the block may have no natural pests and diseases. Thus, large stands of monocultures can occur. It is generally accepted that one plant species will support 10 species of animals. If one species takes over 99% of a given habitat dozens if not hundreds of species are lost from that area and some populations are stressed enough that extinction is possible.
Modern-day genetic technology has granted mankind with the opportunity to bring back extinct species from the dead. If humans have come to possess the DNA from an extinct animal population, it is possible to create an identical clone of the animal in question, effectively “bringing it back from the dead”. Many ethical dilemmas surround the practice of de-extinction, and rightfully so. Recreating an extinct species could produce groundbreaking scientific breakthroughs, generating exciting opportunities for future genetics-based research. However, there could also be monumental consequences: the newly revived, once-extinct species might destroy the ecological equilibrium of modern Earth
Invasive species, (also known as invasive alien species or simply alien species) are defined as any organism (plant, animal, pathogen, or other living thing) that is alien (non-native) to an ecosystem, which can cause adverse economical, ecological, or health effects to native species and/or humans. The roots of these problems all stem from the massive negative ecological impact these organisms are having on the environment (CBD, 2009). For all animal extinctions where the cause is known since the 1600’s, invasive alien species have been a contributing factor 40% of the time (CBD, 2006); the second most contributing factor to extinctions after loss of habitat (GC, 2013). By eliminating native species through competition for resources, predation, and transmittal of disease, invasive species continue to reduce biodiversity in almost all ecosystems around the world (CBD, 2009). In the future, this problem may worsen, and if no action is taken, could lead to a cascading ecological problem so large that whole communities or even ecosystems could collapse.
Frogs are amphibians in the order Anura. The order Anura is broken down into 22 different families of frogs and toads. Although they belong to the same order, frogs and toads are different in a lot of ways. Some of the more distinct differences are their skin and where they live. Frogs usually have smooth moist skin and toads usually have dry watery looking skin. Frogs spend most of their lives in or near water and toads spend more time on land. Amphibian means "double life." Frogs and toads each have two parts to their lives: when they live on water and when they live land. A frog's life starts in the water when it is hatched from an egg as a tadpole. A tadpole looks very different from an adult frog. A tadpole has a tail, no limbs, and breathes through gills. After a while the tadpole goes through metamorphosis. During the change the frog grows limbs, the tail disappears, it uses lungs to breathe, and it doesn't have to live in water anymore. As a tadpole, the frog feeds mostly on vegetation. The tadpoles have a small rasping mouth suited especially for scraping algea from the bottom of ponds. Depending on the species, it can take a few weeks to a year or more for the tadpoles to become fully grown. Not all frogs hatch as tadpoles. Some species of frogs hatch as froglets. Froglets look just like adult frogs but are a lot smaller. Froglets don't go through a metamophosis. Most species that hatch as froglets are found in dry places. Frogs who live in dry places where rains are seasonal have to grow up quickly because a tadpole will die if their temporary pond dries up. Adult frogs can live in water or on land, but it always needs to be near water so its respiratory organs don't dry out.
Thousands of species have become extinct over the last four decades as a result of changes in land use and as a result of global warming. Whether or not the millions of species can adapt and evolve to climate changes is debatable. As this brief overview will report, the human species is not adapting well to the changes. It must be remembered that increases in the levels of carbon dioxide are certainly responsible for the risk many species face, but so is the way land is used, e.g., rain forest destruction. There is a feedback loop wherein plant life and the climate are interdependent. Each affects the other. When forests are cut down, temperatures in that area will rise. Rising temperatures cause other plant life requiring cooler temperatures To die off.
Since the 1980’s scientists have noted the decline of many frog species. People do not know for certain what has caused these declines. A possible factor is pollution, disease, habitat destruction, and acid rain. Another factor may be the thinning of the earth’s protective ozone layer, which allows more harmful ultraviolet radiation from the sun to reach the earth. Because frogs have thin, moist skin and an aquatic tadpole stage, they are easily affected by pollution and changes in the environment.
of species due to a variety of causes. Included is out competition, depletion of resources
Many scientists were fascinated by the creatures that seemed to disappear from the forests of Queensland every year and during this time were thought to be hibernating. Although before they had a chance to study them in further detail the frogs became extinct.
One of the big causes of extinction or the endangerment of species is foreign species entering a habitat. This species that are not native to the land can disrupt the food web in that community. These species take control of the food web and endanger some of the other species. The native species become endangered and over the course of many years they either adapt to their new way or life, the foreign predator leaves or is killed off due to the different environment, or the species is killed off and becomes extinct. Organizations like the “World Wild Li...
Some main causes of Endangerment are habitat loss, pollution, hunting, competition from non-native plants and animals, plant collecting, logging, clearing forests, and trading animal parts. The growing population also causes some effect because man cause most problems. Diseases or viruses are al...