Mammal Population Animal
Topic: Factors affecting the mammal population in the neotropics and the challenges to managing these populations
In terms of biogeography the neotropic refers to one of the world's eight terrestrial ecozone. This ecozone refers consist of the south and central America, the Mexican low , the Caribbean islands and the southern Florida since these regions share a large number of plant and animal groups. Even though the neotropics includes temperate regions such as southern South America it is sometimes used sinuously for the tropical area of South America.
Mammals are distinguished from the other vertebrates by the ability of the females to produce milk for the nourishment of young from the mammary glands present on most of the species, specialized skin glands present in the group of mammals known as monotrems. These glands seep or ooze mill. Other distinguishing features of mammals include the presence of hair or in some cases fur, specialized teeth, and three small bones within the ear, additionally, the presence of the neocortex region of the brain and the ability to maintain endothermy. This is the ability to maintain their body temperature. Also, noticeable is existence of placenta in the ontogeny.
Placental mammals all bear live young, which are nourished before birth in the mother's uterus through a specialized embryonic organ attached to the uterus wall, called the placenta. The placenta is derived from the same membranes that surround the embryos in the amniotic eggs of reptiles, birds, and monotreme mammals. The term "placental mammals" is somewhat of a misnomer because marsupials also have placentae. The difference is that the placenta of marsupials is very short-lived and does not make as much of a contribution to fetal nourishment as it does in eutherians, as "placental mammals" are known scientifically.
Approximately, ¼ of the world's mammals are at a great risk of extinction due to numerous factors. Some of these include natural disasters while others are caused by the negative impact of humans. The report seeks to show the factors affect the mammal population and the challenges to managing the population.
The mammal population is at a risk of becoming extinct due to the fact that there is much degradation and destruction of habitats under stress of population growth. In the neotropics, more than ½ of the mammal population is declining. The main reason for this is deforestation, which is triggered by rapid rates of population growth. Plants are the most abundant and commercial macro organism, worldwide. They play and integral role in the ecosystem since they are producers in the food chain, therefore they are the most critical constituents in the maintenance of dynamic, functional mammalian population. Most mammalian diets consist of plant foods. The plant community has many function in the ecosystem, they help to stabilize the watersheds, provide habitat and cover for numerous organisms (animals and other plants). Plants carry out nitrogen fixation in the atmosphere and stabilize the earth's oxygen content, these processes are essential fro the survival of animals. The occurrence of any modification of the ecological characteristics of the plant and environment can be detrimental in terms of survival even though these organisms are adapted to harsh environmental conditions. Most of these negative modifications that may occur in the environment can greatly affect the rainfall cycle and may reduce the agricultural productivity of that area. Due to these occurrences of these negative processes in the neotropics the mammalian populations are affected.
Due to agricultural and rearing of mammals, deforestation results in commercial exploitation and expansion. In the earlier days (early 1990's) the rate of deforestation was quite higher than that of today since conservation strategies are applied. In the neotropics, there was expansion of many pastures that in turn caused environmental degradation in the region, which would affect the native vegetation soil and aquatic systems, and extending into all types of landscapes. Due to the clearing of the native vegetation in the early 21st century, the mammal population has become threatened.
Poorly planned development has led to the treat among neotropics environments. These poorly planned developments have resulted in occupation or destruction of fragile ecosystem, pollution of rivers and beaches from the waste products of industries, municipal and human waste. For instance, in the most industrialized countries the pollution produced in the area often results in acid rain over forest remnants. Therefore, in areas that are industrialized there is high rate of pollution which in turn can affect the mammalian population since the products released as waste are toxic and can possibly result in the death or infertility of some mammals thus, preventing a new generation of animals.
With the increase, interaction or presence of humans near mammalian territories increases the treat to that community. The presence in many cases results in small scale extraction activities. In additionally, the collection of ornamental and medicinal plants, capturing of these mammals and poaching also causes a decline in population. There can also be pollution for the mammals due to the untreated sewer emission, intentional embankment of lakes and deforestation of mangroves. Reforestation can also be affected by campfires and forest fires.
Numerous fires have occurred in the neotropics which cause a great threat to the animal population since dozens of hectares of native lands were destroyed.
Throughout the years of 1996-2000 the volume of illegal animal trade doubled globally. It is estimated that ten million animals were trapped annually. Generally it can be said that the wildlife trade affects a large number of species as such they are officially threatened. Sport hunting has also been practiced on a small scale nevertheless, it contributes to local extinction.
For tourist accommodation, outstanding landscapes have been selected for such enterprises and exotic plants are introduced to change the surrounding. The largest areas of continuous deforestation along the northern coast coincide with real estate enterprises in the area. Sewage that is untreated pollutes the beaches and the construction of vacation homes, hotels, resorts and other amenities allows for additional pressures on Atlantic forest. This is the main reason of mammalian decline in some parts of the world.
Generally, pollution can drastically affect the livelihood of many organisms. In addition to terrestrial pollution there is also pollution under water, for example, the disturbing case face by many aquatic animals is the underwater noise pollution especially the aquatic mammals. Ocean noise pollution can be described in many ways. The ocean is packed to the surface with loud noise and over time the amount of noise increases. Examples of these noises include military sounds that are a result of defense strategies and research projects carried out. Noise coming from fishing boats, merchant ships, research vessels and oil rigs also contribute to ocean pollution.
Two types of survey are used in the efforts of evolving research on the sounds produced during this type of pollution. These are the sonar survey which can be heard over long distance however these sounds can only be heard for short periods of time and these are used in naval weaponry. The other survey is the seismic one which has a similar effect as the previous but these are more lethal since these are set for weeks or sometimes months. These are used in oil exploration as well as geological studies. Even though these types are serious there are also other sources of the natural disasters such as sea quakes, heavy rains, etc. all of these sounds produced play a significant role in noise pollution for aquatic mammals.
Many aquatic mammals such as whales use calls as a means of communication, due to the noise produced both by man and nature these animals would be unable to communicate. The noise produced also affects special echolocation skills which are used for navigational purposes, foraging for food, and communication within the specific group members.
Marine mammals are also threatened by increasing vessel traffic. A prime example is the threat facing manatees in Florida as growing numbers of high-speed boats take to coastal waterways. These vessels often strike these slow-moving, surface-dwelling herbivores, scarring them for life or killing them. Right whales, the most endangered great whale species in the ocean, are also threatened by ship strikes. Their slow, surface-foraging behavior makes them highly susceptible to collisions in the busy shipping lanes of the North American Atlantic coast, their preferred habitat.
Marine mammals are also threatened by increasing vessel traffic. A major example is the threat facing manatees in Florida as growing numbers of high-speed boats take to coastal waterways. These vessels often strike these slow-moving, surface-dwelling herbivores, scarring them for life or killing them.
The increase in environmental conditions has a significant impact in the mammal populations since they affect their fertility rate. That is, the high temperatures tend to kill the sperms for males and by stressing the females which in turn reduces the blood flow to the uterine tract.
The adult females can be somewhat protected for the high temperatures by shunting the blood to superficial tissues and respiratory muscles. This reduces perfusion of blood to the abdominal viscera, nonrespiratory muscles, and reproductive tract.
An example of exploitation of the mammal, population is the killing of jaguars for the fur trade. Presently, jaguar ranges from Mexico through much of South America, including Colombia, Venezuela, Suriname, Brazil, Peru, Paraguay, and northern Argentina. Recently, jaguars also survived further north in Arizona, New Mexico, Colorado, and Texas. During the 1950s and 1960s thousands of jaguars were killed each year for the fur trade. In the 1960s nearly 15,000 jaguar skins were imported each year into the United States and Europe. During that time, high-quality jaguar coats were sold in New York for as much as $20,000. The 1975 Convention of International Trade in Endangered Species (CITES) treaty prohibited international trade in most wild cats and was dramatically effective in curtailing trade of jaguar skins. By 1990 international trade in jaguar skins had fallen to zero.
However, the jaguar community still faces other human threats. In areas where jaguars roam, much forest has been converted to farms and cattle ranches. Poaching, habitat loss, and competition with subsistence hunters for prey threaten the jaguar throughout its range. As more and more forest is transformed to cattle ranches, jaguars prey on cattle with more frequency. As a result, ranchers actively hunt jaguars to protect their livestock. Conservation groups are working to find ways to minimize jaguar predation on livestock and build local support for conservation.
Management of the mammal population:
The numerous factors that affect mammalian population in the neotropics can be managed to an extent. This therefore means that human beings play an integral role in the management of animals in general. The habitat of mammals should be conserved. Nature conservation deals with the protection, management and enhancement of natural plant and animal communities and occasionally modified vegetation, as representative samples of their kind. Nature conservation also includes the conservation of natural resources or the wise use of the earth's recourses humans.
The term “conservation” came into use in the late 19th century (1800's) and referred to the management, mainly for economic reasons of such valuable natural resources such as timber, fishes, game (these are wild animals hunted for food or sport, preservation of forests, wildlife, parklands, etc. if these resources are conserved that is, if we protect biodiversity and the natural environment, the mammalian population would neither decline nor become extinct since mammals are mostly affected by human impact of hunting, exploitation etc. Also, most mammals rely on plant foods and if the is overharvested or affected in some other way this would mean that there the food supply for the mammals would be limited. Forest management and wild life managers agree that wild life benefits from forest management and cutting of trees. This is so, because a well managed forest provides ample and diverse food and for a variety of wild species.
The main reasons for mammalian extinction are degradation and fragmentation; overharvesting and through the introduction of exotic species and diseases. Generally the causes of wild life population declines are strongly related to social, economic and cultural problems in the areas where these mammals are threatened. By protecting the areas that are threatened, the mammalian population would be less affected. Mammals and other animals are forced to migrate or are they eventually die when wild lands are converted into agricultural or urban areas. Overharvesting does not only involve mammals and other animals for food but also trapping them for the pet trade. As a result this, protected areas are established and this is a key tool in effecting the conservation of biodiversity. These areas are essential for conservation of biodiversity. These are essential for conservation of nature for its use in medicines and improvement of crops and domestication of animals. In designating a protected area certain strategies must be put in place. Management planning is done on an area specific basis and is considered as the key for effective and rational management of protected. Every protected area should have a management plan which guides all development within the area and defines the objectives of the park in relation to the wider region.
Another way of minimizing the extinction rates of many mammals is captive breeding since this focuses on the reproduction of rare animals in captivity. It clears the threats to species breeding. Captive breeding plays a significant role in conserving the species.
From the above information provided it can clearly be seen that humans play a critical role in the decline of mammalian population however, they also provide positive roles in the conservation of these species.
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- www.google.com/Top/Science/Environment/Biodiversity/Conservation/Mammals/ ( date accessed 7th march, 2008)
- http://www.hsiasia.org/Marine/Marine_Marine%20Pollution%20and%20Habitat%20Degradation.htm (date accessed 3rd march, 2008)
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