[Edit] The Paradox of Intensification

Reviewing the evidence on urban intensification, smart growth and their effects on travel behaviour Melia et al. (2011)^[50] found support for the arguments of both supporters and opponents of smart growth measures to counteract urban sprawl. Planning policies that increase population densities in urban areas do tend to reduce car use, but the effect is a weak one, so doubling the population density of a particular area will not halve the frequency or distance of car use.

These findings led them to propose the paradox of intensification, which states:

Ceteris paribus, urban intensification which increases population density will reduce per capita car use, with benefits to the global environment, but will also increase concentrations of motor traffic, worsening the local environment in those locations where it occurs.

[Edit] Debate over traffic and commute times

Those not opposed to low density development argue that traffic intensities tend to be less, traffic speeds faster and, as a result, ambient air pollution is lower. (See demographia's report.) Kansas City, Missouri is often cited as an example of ideal low-density development, with congestion below the mean and home prices below comparable Midwestern cities. Wendell Cox and Randal O'Toole are the leading figures supporting lower density development.

Longitudinal (time-lapse) studies of commute times in major metropolitan areas in the United States have shown that commute times decreased for the period 1969 to 1995 even though the geographic size of the city increased.^[51]

[Edit] Risk of increased housing prices

There is also some concern that Portland-style anti-sprawl policies will increase housing prices. Some research suggests Oregon has had the largest housing affordability loss in the nation,^[52] but other research shows that Portland's price increases are comparable to other Western cities.^[53]

In Australia, it is claimed by some that housing affordability has hit "crisis levels" due to "urban consolidation" policies implemented by state governments.^[54] In Sydney, the ratio of the price of a house relative to income is 9:1.^[55] The issue has at times been debated between the major political parties.^[56]

[Edit] Freedom

There are some sociologists such as Durkheim who suggest there is a link between population density and the number of rules that must be imposed. The theory goes that as people are moved closer together geographically their actions are more likely to noticeably impact others around them. This potential impact requires the creation of additional social or legal rules to prevent conflict. A simple example would be as houses become closer together the acceptable maximum volume of music decreases, as it becomes intrusive to other residents.^[57]

[Edit] Crowding and increased aggression

Numerous studies link increased population density with increased aggression. Some people believe that increased population density encourages crime and anti-social behavior. It is argued that human beings, while social animals, need significant amounts of social space or they become agitated and aggressive.^[58] However, the relationship between higher densities and increased social pathology has been largely discredited ^[59]

18) The best form of tourism for you

19) Endangered species and animals топик

A species that is in danger of extinction throughout all or a significant portion of its range. “Threatened species” is a related term, referring to a species likely to become endangered within the foreseeable future. The main factors that cause species to become endangered are habitat destruction, invasive species, pollution, and overexploitation.

Habitat destruction is the single greatest threat to species around the globe. Natural habitat includes the breeding sites, nutrients, physical features, and processes such as periodic flooding or periodic fires that species need to survive. Humans have altered, degraded, and destroyed habitat in many different ways. Logging around the world has destroyed forests that are habitat to many species. This has a great impact in tropical areas, where species diversity is highest. Although cut forests often regrow, many species depend upon old-growth forests that are over 200 years old; these forests are destroyed much faster than they can regenerate. Agriculture has also resulted in habitat destruction. In the United States, tallgrass prairies that once were home to a variety of unique species have been almost entirely converted to agriculture. Housing development and human settlement have cleared large areas of natural habitat. Mining has destroyed habitat because the landscape often must be altered in order to access the minerals. Finally, water development, especially in arid regions, has fundamentally altered habitat for many species. Dams change the flow and temperature of rivers and block the movements of species up and down the river. Also, the depletion of water for human use (usually agriculture) has dried up vegetation along rivers and left many aquatic species with insufficient water.

The invasion of nonnative species is another major threat to species worldwide. Invasive species establish themselves and take over space and nutrients from native species; they are especially problematic for island species, which often do not have defensive mechanisms for the new predators or competitors. Habitat destruction and invasion of nonnative species can be connected in a positive feedback loop: when habitat is degraded or changed, the altered conditions which are no longer suitable for native species can be advantageous for invasive species. In the United States, approximately half of all endangered species are adversely affected by invasive species.

Pollution directly and indirectly causes species to become endangered. In some cases, pesticides and other harmful chemicals are ingested by animals low on the food chain. When these animals are eaten by others, the pollutants become more and more concentrated, until the concentration reaches dangerous levels in predators and omnivores. These high levels cause reproductive problems and sometimes death. In addition, direct harm often occurs when pollutants make water uninhabitable. Agriculture and industrial production cause chemicals such as fertilizers and pesticides to reach waterways. Lakes have become too acidic from acid rain. Other human activities such as logging, grazing, agriculture, and housing development cause siltation in waterways. Largely because of this water pollution, two out of three fresh-water mussel species in the United States are at risk of extinction. See also Acid rain; Water pollution.

Many species have become endangered or extinct from killing by humans throughout their ranges. For example, the passenger pigeon, formerly one of the most abundant birds in the United States, became extinct largely because of overexploitation. This overexploitation is especially a threat for species that reproduce slowly, such as large mammals and some bird species. Overfishing by large commercial fisheries is a threat to numerous marine and fresh-water species.

Efforts to save species focus on ending exploitation, halting habitat destruction, restoring habitats, and breeding populations in captivity. In the United States, the Endangered Species Act of 1973 protects endangered species and the ecosystems upon which they depend. Internationally, endangered species are protected from trade which depletes populations in the wild, through the Convention on International Trade in Endangered Species (CITES). Over 140 member countries act by banning commercial international trade of endangered species and by regulating and monitoring trade of other species that might become endangered. For example, the international ivory trade was halted in order to protect elephant populations from further depletion.

Typically, the first step is identifying which species are in danger of extinction throughout all or part of their range and adding them to an endangered species list. In the United States, species are placed on the endangered species list if one or more factors puts it at risk, including habitat destruction or degradation, overutilization, disease, and predation. Florida and California contain the most endangered species of all the contiguous 48 states. Hawaii has more endangered species than any other state. Hawaii, like other islands, has a diversity of unique species that occur nowhere else in the world. These species are also highly susceptible to endangerment because they tend to have small population sizes, and because they are particularly vulnerable to introduced competitors, predators, and disease.

For many endangered species, a significant captive population exists in zoos and other facilities around the world. By breeding individuals in captivity, genetic variation of a species can be more easily sustained, even when the species' natural habitat is being destroyed. Some species exist only in captivity because the wild population became extinct. For a few species, captive individuals have been reintroduced into natural habitat in order to establish a population where it is missing or to augment a small population. Depending on the species, reintroduction can be very difficult and costly, because individual animals may not forage well or protect themselves from predators. See also Ecology; Extinction (biology).

20) How can the impact of tourism be minimized

Ecotourism is a form of tourism that involves visiting natural areas—in the remote wilderness or urban environments. According to the definition and principles of ecotourism established by The International Ecotourism Society (TIES) in 1990, ecotourism is "Responsible travel to natural areas that conserves the environment and improves the well-being of local people." (TIES, 1990). Martha Honey, expands on the TIES definition by describing the seven characteristics of ecotourism, which are:

• Involves travel to natural destinations

• Minimizes impact

• Builds environmental awareness

• Provides direct financial benefits for conservation

• Provides financial benefits and empowerment for local people

• Respects local culture

• Supports human rights and democratic movements^[4]

^[5][6] such as:

• conservation of biological diversity and cultural diversity through ecosystem protection

• promotion of sustainable use of biodiversity, by providing jobs to local populations

• sharing of socio-economic benefits with local communities and indigenous peoples by having their informed consent and participation in the management of ecotourism enterprises

• tourism to unspoiled natural resources, with minimal impact on the environment being a primary concern.

• minimization of tourism's own environmental impact

• affordability and lack of waste in the form of luxury

• local culture, flora and fauna being the main attractions

• local people benefit from this form of tourism economically, often more than mass tourism

Ecotourism Society Pakistan (ESP) explains "Ecotourism is a travel activity that ensures direct financial support to local people where tourism activities are being generated and enjoyed. It teaches travellers to respect local cultures of destinations where travellers are visiting. It supports small stakeholders to ensure that money must not go out from the local economies. It discourage mass tourism, mass constructions of hotels, tourism resorts and mass activities in fragile areas". For many countries, ecotourism is not simply a marginal activity to finance protection of the environment, but is a major industry of the national economy. For example, in Costa Rica, Ecuador, Nepal, Kenya, Madagascar and territories such as Antarctica, ecotourism represents a significant portion of the gross domestic product and economic activity.^[5][7]

Ecotourism is often misinterpreted as any form of tourism that involves nature Jungle tourism. In reality, many ecotourism activities often consist of placing a hotel in a splendid landscape, to the detriment of the ecosystem. According to them, ecotourism must above all sensitize people to the beauty and the fragility of nature. They condemn some operators as greenwashing their operations: using the labels of "green" and "eco-friendly”, while behaving in environmentally irresponsible ways.

Although academics disagree about who can be classified as an ecotourist and there is little statistical data, some estimate that more than five million ecotourists - the majority of the ecotourist population - come from the United States, with many others from Western Europe, Canada and Australia.^[5]

Currently, there are various moves to create national and international ecotourism accreditation programs, although the process is also controversial.^[8] National ecotourism certification programs have been put in place in countries such as Costa Rica, Australia, Kenya and Sweden.