Photo 7.1
The Great White Shark Carcharodon carcharius (Vulnerable) is a widely but sparsely distributed top predator with a very low reproductive potential and high vulnerability to target and bycatch fisheries (commercial and recreational). The notoriety of this shark as an ultimate Hollywood monster encourages inflated values for Great White products, and encourages illicit trade in shark parts that is difficult to assess and control. Where detailed population data are available, these indicate that the abundance and average size of white sharks have declined.
Photo: © Jeremy Stafford-Deitsch.
For conservation action to be effective, it is important to understand not just the needs of individual species, but also the context in which conservation efforts will need to take place. A better understanding of human demand and impact on natural resources can help inform decisions and guide conservation efforts so that conflicts in interests between humans and biodiversity can be minimized. Here we compare current distribution patterns of threatened species with recent and future human demographic variables, and with gross national income at the national level. The analysis focuses on threatened mammals, birds and amphibians, as these are the only groups that have been completely assessed for threatened status, and for which distribution maps are available for almost all threatened species. This analysis is not focused on determining causal relationships between social and economic factors and the status of threatened species, but rather on illustrating patterns of association that illuminate some of the challenges faced when trying to conserve biodiversity in an increasingly human-dominated world.
In order to highlight those regions where human demands on resources and biodiversity conservation are most likely to be in conflict, the current human population density and distribution of threatened species were compared (Figure 7.1; for methodology used, see Appendix 2g).
The regions of the world that have few threatened species and low human population density are at high latitudes, in arid regions, or in wilderness areas (an example of each being northern Canada, the Sahara Desert, and the Amazon basin). Such regions can be considered good opportunities for preventive conservation measures since there is little human demand at present for resources and species are currently relatively unthreatened. Regions that have a large number of threatened species but a relatively low human population density, for example Bolivia and the Russian Far East, are uncommon.
Figure 7.1
The total number of threatened species of mammals, birds and amphibians compared to human population density. Each grid cell is coded according to the combined value of the two variables.
Photo: © Digital Vision.
Photos 7.2 and 7.3 (top to bottom)
Many parts of the world are impacted by high population densities of people (Photo 7.2), however, there are still a number of unpopulated wilderness areas like the Sahara Desert (Photo 7.3) that have few threatened species.
Photo: © Chris Magin.
In some regions, such as Europe and eastern North America, high population densities coincide with low numbers of threatened species. This is partly due to decreasing numbers of species with increasing latitude (Figure 5.5), but perhaps also a reflection of species susceptible to habitat loss in these regions having declined a long time ago (see Section 6.10.4 on extinction filters). In general, these regions are less of a concern for the conservation of globally threatened species than most other parts of the world.
The regions where high human population density and high numbers of threatened species overlap are mostly in Asia (in particular southeast China, the Western Ghats of India, the Himalayas, Sri Lanka, Java (Indonesia), the Philippines, and parts of Japan) as well as the Albertine Rift in Central Africa and the Ethiopian Highlands. These regions present the greatest conservation challenges, as the needs of billions of humans must be met while also working to prevent the extinction of large numbers of species.
To gain some understanding of how the human context changes with time, the annual human population growth for 2002 for each country (World Bank 2004) was compared to the number of threatened species (Figure 7.2; for methodology used, see Appendix 2g).
Figure 7.2
Country-level map of the total number of threatened species of mammals, birds and amphibians compared to human population growth in 2002. Each country is coded according to the combined value of the two variables.
Photo 7.4
New York City – high population densities in eastern North America coincide with low numbers of threatened species.
Photo: © Craig Hilton-Taylor.
Photo 7.5
Most African countries, despite very high population growth rates, have a relatively low population density, and a subsistence lifestyle is still commonplace.
Photo: © Craig Hilton-Taylor.
Photo 7.6
Many developing nations are experiencing high population growth and face conflicting needs between the developed and undeveloped sectors of the population.
Photo: © Sue A. Mainka.
Figure 7.3
Country level map of the total number of threatened species of mammals, birds and amphibians compared to Gross National Income (GNI) per capita in 2003. Each country is coded according to the combined value of the two variables.
The countries that are most densely populated at present are not necessarily those that are currently experiencing a high human population growth rate. In general the highest human population densities are found in Asia whereas the highest population growth rates are in Africa. Most African countries, however, currently have a relatively low level of population density so the impact of population growth might be more easily absorbed. With the annual rate of population growth declining in almost all countries, it is debatable whether these African countries will ever reach the high population density levels of some Asian countries today. Countries with high population growth rates and high numbers of threatened species such as Cameroon, Colombia, Ecuador, India, Madagascar, Malaysia, Peru, Philippines, Tanzania, and Venezuela are areas where conflicts between the needs of threatened species and increasing human populations are anticipated to rapidly intensify. Countries that currently have a low human population density but a high rate of population growth could be opportunistic places for pre-emptive conservation initiatives, for example Bolivia, Papua New Guinea, Namibia, Angola, and the countries of northern Africa. The Amazonian slopes of the Andes is also a region of relatively low human population density at present, and all of the Andean countries have relatively high population growth rates, as well as being extremely important for threatened species.
Conserving biodiversity requires significant financial resources. By comparing a country's economic strength (measured as Gross National Income (GNI) per capita) to the number of threatened species, an indication of both the need for conservation and the availability of financial resources can be determined (Figure 7.3; for methodology used, see Appendix 2g).
Countries with relatively strong economies but a large number of threatened species include Argentina, Australia, Malaysia, Mexico, United States, and Venezuela. However not all of these countries have significant funds available for threatened species conservation. Those countries that have a large number of threatened species but a relatively low GNI per capita include Brazil, Cameroon, China, Colombia, Ecuador, India, Indonesia, Madagascar, Peru, and the Philippines. These countries share a large responsibility towards conserving globally threatened species but are less likely to have financial resources available for conservation purposes. Other countries, particularly those in Europe, have significant financial resources but generally very few globally threatened species.
People and threatened species are often concentrated in the same areas. At present these areas are mostly in Asia as well as the Albertine Rift in Central Africa and the Ethiopian Highlands.
Future conflicts between the needs of threatened species and rapidly increasing human populations are predicted to occur in Cameroon, Colombia, Ecuador, India, Madagascar, Malaysia, Peru, Philippines, Tanzania, and Venezuela.
Countries that currently have a low human population density but a high rate of population growth could be opportunistic places for pre-emptive conservation initiatives. For example, Bolivia, Papua New Guinea, Namibia,Angola, and the countries of North Africa.
Countries with a large number of threatened species are often not financially able to invest in conservation, such as Brazil, Cameroon, China, Colombia, Ecuador, India, Indonesia, Madagascar, Peru, and the Philippines.
Photo 7.7
The Queen Triggerfish Balistes vetula (Vulnerable) is considered to be an excellent food fish but may be poisonous to some people. The species is a popular gamefish and is captured for the aquarium trade. It is a widespread species in the Atlantic, occurring in the east from the Azores south to Angola and in the west from Massachusetts in the US south to Brazil.
Photo: © John E. Randall.