Declining Frog Populations Summary
The impacts of free-roaming domestic dogs on the desert tortoise have been studied at SAGU and found to Declining Frog Populations Summary an issue Zylstra Essay On Causes Of Flood In Malaysia Picking Declining Frog Populations Summary up from a pandemic. Climate change is cited The Importance Of Good Nutrition And Body Health as one Liesel Memingers Relationship In The Book Thief the main Visual Rhe-Torical Analysis Essay: Save Water Ad-Vertisement causes of amphibian population declines. Diagnosis of chytridiomycosis in amphibians by histologic examination. Longcore, C.
This Fungi Could Save the Frog Population Forever
A year-long study in a Texas wildlife management area found road traffic affected reptiles extensively in the fall and spring and amphibians in the spring and summer. Road mortality in Arizona is also high during the summer rain monsoon period, when amphibians are drawn to breeding sites and some snake breeding movements are also high. Urban development also increases conflicts between venomous species and humans Sullivan et al. Wildfires may also lead to long-term or permanent loss of habitat for amphibians and reptiles.
Such loss includes the filling-in or sedimentation of stream pools. In SAGU, many tinajas bedrock pools that are home to the lowland leopard frog have been buried by eroded material resulting from stand-replacing widlifes occurring at higher elevations Parker The disease chytridiomycosis is caused by a recently identified species of parasitic fungus Batrachochytrium dendrobatidis , known as the amphibian chytrid fungus. Chytridiomycosis is considered a major threat to amphibians worldwide, causing population declines and species extinctions. The disease is thought to have originated in Africa, spreading rapidly since the s Australia Department Environment and Heritage , although this is debated and much is still unknown about the disease.
Amphibian chytrid fungus attacks keratin in the skin of amphibians. The water-dependent fungus spreads via free-swimming zoospores, which colonize amphibian skin and develop into zoosprangia. The fungus is believed to be able to persist in aquatic environments without amphibians. Amphibian larvae are not lethally affected, but they can carry the fungus in mouthparts and toe tips during later stages of development. Some amphibian species can carry the fungus without being killed by it, and they may serve as vectors of the pathogen to more susceptible species. The responses of amphibian populations infected with the fungus range from no perceptible impact, to mass mortality events, to severe decline without recovery.
In the western U. Reports of the disease in the Southwest include infections in lowland leopard frogs Lithobates yavapaiensis , Chiricahua leopard frogs Lithobates chiricahuensis , and canyon tree frogs Hyla arenicolor in eastern, central, and southern Arizona Bradley et al. The disease may persist in healthy amphibian populations once an epidemic wave has passed. The genus Ranavirus family Iridoviridiae , only recently discovered, causes disease in amphibians, reptiles, and fish. Amphibian ranaviruses are considered a global threat to amphibian populations due to their high virulence and rapid expansion to areas with previously unexposed populations.
Death is thought to result from organ failure due to tissue necrosis and possibly from secondary bacterial infections. Ranavirus can be spread in various ways, including through infected food, water, human handling, introduction of fish and amphibians e. The disease is thought to be particularly associated with disturbed or degraded habitats and high amphibian densities.
Susceptibility to disease may be influenced by many factors, including chemical exposure and temperature. Ranavirus has not been shown to cause local or species extinctions, but because ranavirus outbreaks sometimes kill all or most of an entire year class in a population, the persistence of local amphibian populations could be threatened by episodic die-offs.
A virus thought to be an iridovirus was found to be the primary cause of periodic population crashes in the Sonora tiger salamander Ambystoma tigrinum stebbinsi in southern Arizona Jancovich et al. Another disease of concern for reptiles is a widespread upper respiratory tract disease URTD caused by the bacterium Mycoplasma agassizii Gibbons et al. This contagious disease may be part of the cause of population declines in desert tortoises Gopherus agassizii in the Mohave Desert Ivanyi et al. In addition to desert tortoises in the Mohave Desert, M. Symptoms of the disease are a runny or wet nose and eyes. The disease is spread by direct contact and probably by an infected animal sneezing and leaving drops of muscous.
Captive tortoises should not be released into the wild, because, among other reasons, they could spread M. Non-native invasive species are another threat to amphibian and reptile populations. Non-native invasive species may act as predators of or competitors with native species. Bullfrogs Lithobates catesbeianus , for example, were introduced in the s west of the Rocky Mountains, where they are efficient predators of amphibians and some reptiles Marks For example, the bullfrog is thought to be a primary cause of declines of leopard frogs including the federally-threatened Chiricahua leopard frog and gartersnakes in Cochise County, southern Arizona Rosen and Schwalbe Few young Mexican gartersnakes Thamnophis eques , a highly aquatic species, were found to survive in the presence of bullfrogs, but the snakes may survive well once they outgrow the sizes susceptible to bullfrog predation.
Non-native fish are also a major problem for native aquatic amphibians and reptiles. Non-native fish compete with or eat native fish that are needed by the herpetofauna species, such as narrow-headed Thamnophis rufipunctatus and Mexican gartersnakes. For example, research by the U. Geological Survey found that the distribution pattern of narrow-headed garter snakes in Oak Creek, Arizona, was similar to the availability of smooth-bodied fish with soft fins a major food source Nowak a. Historically, it was distributed from southwestern British Columbia, Canada to northeastern California.
Today there are approximately 46 locations in British Columbia, Washington and Oregon. In , the U. Fish and Wildlife Service concluded that federal listing of the Oregon Spotted Frog as Endangered or Threatened was warranted but precluded from listing by other higher priority species. It is currently a Federal Candidate Species. Museum specimens and substantiated accounts indicate Oregon Spotted Frogs were found in both the Puget Trough and East Cascades ecoregions.
The decline in the occurrence and population sizes of Oregon Spotted Frogs is attributable to several major human-caused stressors. These include:. Oregon Spotted Frogs have specific life history traits, habitat requirements, and population characteristics that limit their distribution and make them vulnerable to these changes. Additional threats include the geographic isolation of Oregon Spotted Frog populations and the increase of water-borne pollutants and diseases. This list of threats is neither exhaustive nor independent, as a number of factors are interconnected.
Climate change is a looming threat of concern because it involves potential changes likely to have severe effects on Oregon Spotted Frogs across their geographic range. Given the trajectory of habitat change and interrelated conditions that threaten this species, Oregon Spotted Frogs in Washington are not expected to recover without intervention. Habitat management will be an essential part of the recovery plan for this species. Also, less food is being grown such as vegetables and fruits.
If less food is being grown that means that food prices in the grocery stores will increase. The reading states that several methods have been proposed to solve the problem of declining frog populations and provides three reasons of support. However, the professor states that these methods are not a practical solution and refutes each of the authors ' reasons. First, the reading states that if laws laws prohibited the farmers from using harmful pesticides, it would significiantly reduce the harm pesticides cause to frogs.
The professor opposes this point by saying that this is not an economical and practical solution. The professor points out that stop using pesticides that will make farmers lose a lot of crops. The professor adds that will cause a huge disadvantage to farmers by reducing their yeilds and cannot help them to compete with other farmers who they use …show more content… The professor counters this point by saying that there are two problems with this point. First, the professor states that each frog should be treated individually with antifungal. The professor adds that doing this process on a large scale will be difficult because people should capture and treat frogs individually.
Second, the professor adds that frogs ' offspring also should be treated with antifungal again and again. Therefore, the professor states that each new generation should be treated and that 's a complicated and expensive process. Third, the reading states that if water habitats were better protected from excessive water use, many frogs species would recover. The professor refutes this point by saying that this method will not save frogs ' populations. The professor points out that global warming is the biggest problem that caused a decline in frogs ' population, not the water loss.
The professor explains that a lot of species were extinct because of water loss. And, stop using of lakes and marshes water will not prevent the global warming because they did not cause global. Show More. Stop The Cane Toad Analysis Words 2 Pages The reading states that several measures have been proposed to stop the spread of the cane toad in Australia and provides three reasons of support. Read More. Sea Otter Decline Words 1 Pages The lecturer and the reading passage offer two theories to explain why the sea otter population is in rapid decline. The Pros And Cons Of Poaching Laws Words 4 Pages Due to poaching, your favorite animals might be getting killed each day slowly decreasing their population, even though there are laws that are supposed to prevent this.
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