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  • The Necessity, Promise and Challenge of Automated Biodiversity Surveys
    Environ. Conserv. (IF 2.759) Pub Date : 2019-07-18
    Justin Kitzes; Lauren Schricker

    We are in the midst of a transformation in the way that biodiversity is observed on the planet. The approach of direct human observation, combining efforts of both professional and citizen scientists, has recently generated unprecedented amounts of data on species distributions and populations. Within just a few years, however, we believe that these data will be swamped by indirect biodiversity observations that are generated by autonomous sensors and machine learning classification models. In this commentary, we discuss three important elements of this shift towards indirect, technology driven observations. First, we note that the biodiversity data sets available today cover a very small fraction of all places and times that could potentially be observed, which suggests the necessity of developing new approaches that can gather such data at even larger scales, with lower costs. Second, we highlight existing tools and efforts that are already available today to demonstrate the promise of automated methods to radically increase biodiversity data collection. Finally, we discuss one specific outstanding challenge in automated biodiversity survey methods, which is how to extract useful knowledge from observations that are uncertain in nature. Throughout, we focus on one particular type of biodiversity data - point occurrence records - that are frequently produced by citizen science projects, museum records and systematic biodiversity surveys. As indirect observation methods increase the spatiotemporal scope of these point occurrence records, ecologists and conservation biologists will be better able to predict shifting species distributions, track changes to populations over time and understand the drivers of biodiversity occurrence.

    更新日期:2020-01-04
  • Spatial modelling of biodiversity conservation priorities in Portugal’s Montado ecosystem using Marxan with Zones
    Environ. Conserv. (IF 2.759) Pub Date : 2019-08-13
    Rute Pinto; Paula Antunes; Stefan Blumentrath; Roy Brouwer; Pedro Clemente; Rui Santos

    Spatial models are increasingly being used to target the most suitable areas for biodiversity conservation. This study investigates how the spatial tool Marxan with Zones (MARZONE) can be used to support the design of cost-effective biodiversity conservation policy. New in this study is the spatial analysis of the costs and effectiveness of different agro-environmental measures (AEMs) for habitat and biodiversity conservation in the Montado ecosystem in Portugal. A distinction is made between the financial costs paid to participating landowners and farmers for adopting AEMs and the broader economic opportunity costs of the corresponding land-use changes. Habitat and species conservation targets are furthermore defined interactively with the local government agency responsible for the management of protected areas, while the costs of agro-forestry activities and alternative land uses are estimated in direct consultation with local landowners. MARZONE identifies the spatial distribution of priority areas for conservation and the associated costs, some of which overlap with existing protected areas. These results provide useful insights into the trade-offs between nature conservation and the opportunity costs of protecting ecologically vulnerable areas, helping to improve current and future conservation policy design.

    更新日期:2020-01-04
  • Brazil’s new president and ‘ruralists’ threaten Amazonia’s environment, traditional peoples and the global climate
    Environ. Conserv. (IF 2.759) Pub Date : 2019-07-24
    Lucas Ferrante; Philip M Fearnside

    Jair Bolsonaro (Brazil’s new president) and “ruralists” (large landholders and their representatives) have initiated a series of measures that threaten Amazonia’s environment and traditional peoples, as well as global climate. These include weakening the country’s environmental agencies and forest code, granting amnesty to deforestation, approving harmful agrochemicals, reducing protected areas, and denying the existence of anthropogenic climate change. Both the measures themselves and the expectation of impunity they encourage have spurred increased deforestation, which contributes to climate change and to land conflicts with traditional peoples. Countries and companies that import Brazilian beef, soy and minerals are stimulating these impacts.

    更新日期:2020-01-04
  • Are we ready for elasmobranch conservation success?
    Environ. Conserv. (IF 2.759) Pub Date : 2019-08-06
    John K Carlson; Michelle R Heupel; Chelsey N Young; Jessica E Cramp; Colin A Simpfendorfer

    None

    更新日期:2020-01-04
  • Sea cucumber management strategies: challenges and opportunities in a developing country context
    Environ. Conserv. (IF 2.759) Pub Date : 2019-07-24
    Merrill Baker-Médard; Kristina Natalia Ohl

    Sea cucumbers play a critical role in maintaining healthy marine ecosystems. Sea cucumbers are also a key source of income for millions of small-scale fishers worldwide. The lucrative nature of this industry has led to severe reductions in sea cucumber populations in numerous regions globally. A large proportion of sea cucumber fisheries are located in developing countries, which present unique challenges to management, including addressing highly decentralized methods of extraction and processing, limited economic and technological resources for governance and, in many cases, a high dependency on sea cucumbers as a primary source of income for small-scale coastal fishers. In this review, we review the benefits and challenges of seven categories of sea cucumber management strategies used globally in developing countries, including gear restrictions, size and weight limits, effort and catch controls, temporal closures, area closures, value chain licensing and territorial use rights in fisheries. We conclude that sea cucumber management in developing countries could benefit from focusing regulatory solutions on narrowed parts of the value chain, coupling production-based management strategies with processing and export regulations and providing avenues for local fishers to inform policy at the local, regional and national levels.

    更新日期:2020-01-04
  • Public support for protected areas in new forest frontiers in the Brazilian Amazon
    Environ. Conserv. (IF 2.759) Pub Date : 2019-08-27
    Helenilza Ferreira Albuquerque Cunha; Adriano Ferreira de Souza; José Maria Cardoso da Silva

    Gazetting and maintaining protected areas (PAs) are political processes and, as such, depend on wider society’s support in order to achieve their aims. In this paper, we evaluated the influence of gender, education, age, income, place of origin and place of residence on public support for PAs in the Brazilian state of Amapá, a new tropical forest frontier. We gathered 615 complete interviews with adults living in both rural and urban settings. We found that most (90.5%) of the participants support PAs and that this attitude is more likely to exist among urban than rural participants. We found that gender, education, age, income and place of origin did not influence support for PAs. Biodiversity conservation is the most common reason why PAs receive public support. In contrast, participants who do not favour PAs see them as providing no benefit to people. We suggest that support by local political leaders from dominant and rival political parties for conservation helps to promote acceptance of PAs by stakeholders. However, relatively low support for PAs among rural participants could indicate that the expectations of these populations regarding the social benefits associated with this conservation policy have yet to be fulfilled.

    更新日期:2020-01-04
  • Impacts of Fire on Forest Biomass Dynamics at the Southern Amazon Edge
    Environ. Conserv. (IF 2.759) Pub Date : 2019-07-19
    Denis S Nogueira; Beatriz S Marimon; Ben Hur Marimon-Junior; Edmar A Oliveira; Paulo Morandi; Simone M Reis; Fernando Elias; Eder C Neves; Ted R Feldpausch; Jon Lloyd; Oliver L Phillips

    Over recent decades, biomass gains in remaining old-growth Amazonia forests have declined due to environmental change. Amazonia’s huge size and complexity makes understanding these changes, drivers, and consequences very challenging. Here, using a network of permanent monitoring plots at the Amazon–Cerrado transition, we quantify recent biomass carbon changes and explore their environmental drivers. Our study area covers 30 plots of upland and riparian forests sampled at least twice between 1996 and 2016 and subject to various levels of fire and drought. Using these plots, we aimed to: (1) estimate the long-term biomass change rate; (2) determine the extent to which forest changes are influenced by forest type; and (3) assess the threat to forests from ongoing environmental change. Overall, there was no net change in biomass, but there was clear variation among different forest types. Burning occurred at least once in 8 of the 12 riparian forests, while only 1 of the 18 upland forests burned, resulting in losses of carbon in burned riparian forests. Net biomass gains prevailed among other riparian and upland forests throughout Amazonia. Our results reveal an unanticipated vulnerability of riparian forests to fire, likely aggravated by drought, and threatening ecosystem conservation at the Amazon southern margins.

    更新日期:2020-01-04
  • Biogeographically significant units in conservation: a new integrative concept for conserving ecological and evolutionary processes
    Environ. Conserv. (IF 2.759) Pub Date : 2019-08-30
    M Paula Quiroga; Lucia Castello; Vilma Quipildor; Andrea C Premoli

    We combined tools of phylogeography, population genetics and biogeographical interpretation to analyse a group of phylogenetically independent lineages (animals and plants) that coexist within the same geographical region, yet under markedly different environments, in order to identify generalized barriers for gene flow. We tested the hypothesis that major geographic features have produced a concordant genetic structure in phylogenetically independent lineages. A rigorous bibliographic search was performed, selecting available molecular information from six taxa occupying distinct southern biomes of South America: Yungas, Prepuna, Puna and northern Monte. We estimated within-population genetic diversity, the genetic structure and haplotype phylogenies to assemble distribution maps of genetic barriers for each species. We found a strong association between genetic variation and latitudinal distribution of populations. We detected a major barrier for six taxa at 27°S latitude and a second one for a group of three species at 25–26°S. Two alternative non-exclusive hypotheses – geology and/or climate – explain concordant genetic barriers in divergent lineages. We suggest that the term ‘biogeographically significant units’ portrays a group of populations of phylogenetically unrelated taxa that inhabit the same geographic region that have been similarly impacted by major physical events, which can be used to identify priority areas in landscape conservation.

    更新日期:2020-01-04
  • Differences in women’s and men’s conservation of cacao agroforests in coastal Ecuador
    Environ. Conserv. (IF 2.759) Pub Date : 2019-08-13
    Trent Blare; Pilar Useche

    Stakeholder preferences for the conservation of cacao agroforests are scarcely known. Here, a revealed preference model was used to estimate the value that smallholders place on the conservation of their cacao agroforests in coastal Ecuador. Variables in the model included plot-level data (the gender of those who owned and managed the plot, profit, land title and years of ownership) and household demographic data (ages, educational levels and wealth indicators). Households were willing to give up some profit to conserve agroforests especially if they had managed the plot longer. Furthermore, when women were included in the management of a plot, the household was more likely to conserve the cacao agroforest, but the gender of the person who owns the plot had no effect on the probability of conserving the agroforest. These findings provide further evidence of the gender differences in preferences for agroforests and that more inclusive land-use decisions may lead to the use of more sustainable farming practices. They also demonstrate that policies that encourage inclusive land ownership do not necessarily ensure equal gender participation in plot decision-making and management.

    更新日期:2020-01-04
  • Integrating conservation and socioeconomic development: the potential of community nurseries in Mexican protected areas
    Environ. Conserv. (IF 2.759) Pub Date : 2019-08-02
    Adriana L Luna-Nieves; Eduardo García-Frapolli; Consuelo Bonfil; Jorge A Meave; Guillermo Ibarra-Manríquez

    Community nurseries within natural protected areas (NPAs) represent an attractive option to link biodiversity conservation with socioeconomic development, yet their functioning lacks proper assessment. Here, we analyse the national context of community nurseries in Mexican NPAs and suggest a specific framework to evaluate their viability. First, we examine the impact of a major governmental funding programme on these projects. Next, we conduct a case study in a focal nursery to identify challenges faced by its operation. Despite the large number of community nurseries funded by the programme, current performance indicators are not suitable to assess their viability. In turn, the case study reveals this nursery’s partial success, with a clear contribution to social development but a limited impact on economic improvement and vegetation conservation. Regardless of the characteristics of individual community nurseries, we suggest a framework that is potentially useful for evaluating community nursery viability, which enables agencies to detect problems, find solutions and use resources efficiently, while balancing biodiversity conservation and development.

    更新日期:2020-01-04
  • Understanding knowledge threatened by declining wild orchid populations in an urbanizing China (Sichuan)
    Environ. Conserv. (IF 2.759) Pub Date : 2019-07-24
    Barnabas C Seyler; Orou G Gaoue; Ya Tang; David C Duffy

    With rapid urbanization worldwide, most people now live in cities, but the effects of urbanization on knowledge about the natural environment is not well studied. Due to the importance of Cymbidium to Chinese traditional culture, we tested how urbanization influences the distribution of orchid knowledge across various knowledge domains at risk of loss due to declining orchid populations. Participants in the Cymbidium trade were interviewed in three distinct urbanization-level jurisdictions in Sichuan, China: Puge (low urbanization), Huili (moderate urbanization) and Chengdu (high urbanization). Using photographic cue-cards of nine Cymbidium taxa, we assessed aggregate and specific knowledge held by 91 orchid collectors/traders across the urbanization gradient. Contrary to expectations, we found that urbanization and orchid knowledge were positively related, but this varied by knowledge type, with moderate urbanization showing significantly higher knowledge in two domains. Our findings suggest that a generalizable understanding of how urbanization affects knowledge must account for differences in knowledge types and geographic/cultural scales, with implications for biocultural diversity conservation in an increasingly urban world.

    更新日期:2020-01-04
  • An evaluation of local, national and international perceptions of benefits and threats to nature in Tierra del Fuego National Park (Patagonia, Argentina)
    Environ. Conserv. (IF 2.759) Pub Date : 2019-08-15
    Aaron Mrotek; Christopher B Anderson; Alejandro EJ Valenzuela; Leah Manak; Alana Weber; Peter Van Aert; Mariano Malizia; Erik A Nielsen

    Environmental scientists and managers increasingly recognize that socio-cultural evaluations expand the understanding of human–nature relationships. Here, user groups’ perceptions of the benefits from and threats to nature were analysed in Tierra del Fuego National Park, Argentina. We hypothesized that the different relationships of users to this place would lead to significantly different valuations among local Ushuaia residents (n = 122), Argentine nationals (n = 147) and international tourists (n = 294). All users perceived a broad spectrum of benefits. The three groups assessed intrinsic and relational values more highly than instrumental benefits, and significant differences included a higher mean valuation of benefits by Argentine visitors. Overall, threats were less perceived than benefits, and significant differences included a higher mean threat assessment by Ushuaia residents. To explain these relationships, we found that mean valuations of benefits and threats were weakly related to increased biodiversity knowledge for residents and international tourists, but not for Argentine visitors. These findings can orient environmental management in Patagonia and elsewhere by identifying areas where information can improve user experiences and by contributing a more pluralistic understanding of nature from multiple stakeholders.

    更新日期:2020-01-04
  • Jaguar hunting in Amazonian extractive reserves: acceptance and prevalence
    Environ. Conserv. (IF 2.759) Pub Date : 2019-08-22
    Elildo AR Carvalho

    Hunting is a major threat to the endangered jaguar in Brazil. Effective interventions for jaguar conservation demand a better understanding of the prevalence and motivations for hunting. In this study, I investigate the prevalence of jaguar hunting and the potential factors driving the acceptance of this behaviour among residents of two extractive reserves in the eastern Brazilian Amazonia. Between September and October 2013, I surveyed 134 households to assess people’s acceptance of jaguar hunting and potential predictors of acceptance using multiple-item rating scales. To estimate the prevalence of jaguar hunting, I used direct questioning and the randomized response technique. Acceptance of jaguar hunting was neutral to slightly positive on average, being related negatively to educational level and to people’s perceptions of risk of suffering sanctions for hunting a jaguar and related positively to perception of jaguars as a threat to humans. The prevalence rates of jaguar hunting among surveyed households were 9% and 23% according to direct questioning and the randomized response technique, respectively. The results suggest that investments in education and law enforcement may help decrease local support for jaguar hunting in the study area.

    更新日期:2020-01-04
  • The conservation value of forest fragments in the increasingly agrarian landscape of Sumatra
    Environ. Conserv. (IF 2.759) Pub Date : 2019-07-22
    Sarah R Weiskopf; Jennifer L McCarthy; Kyle P McCarthy; Alexey N Shiklomanov; Hariyo T Wibisono; Wulan Pusparini

    Destruction of tropical rainforests reduces many unprotected habitats to small fragments of remnant forests within agricultural matrices. To date, these remnant forest fragments have been largely disregarded as wildlife habitat, and little is known about mammalian use of these areas in Sumatra. Here, we conducted camera trap surveys (2285 trap-nights) within Bukit Barisan Selatan National Park and five surrounding remnant forest fragments during 2010–2013 and used species composition metrics to compare use. We found 28 mammal species in the protected forest and 21 in the fragments. The fragments harboured a subset of species found in the protected forest and several species not observed in the protected forest. Critically endangered species such as Sunda pangolin (Manis javanica) and Sumatran tiger (Panthera tigris sumatrae) were found in the forest fragments, along with species of conservation concern such as marbled cat (Pardofelis marmorata) and Asiatic golden cat (Pardofelis temminckii). The biodiversity found within the fragments suggests that these small patches of remnant forest may have conservation value to certain mammal species and indicates the importance of further research into the role these habitats may play in landscape-level, multispecies conservation planning.

    更新日期:2020-01-04
  • ENC volume 46 issue 4 Cover and Front matter
    Environ. Conserv. (IF 2.759) Pub Date : 2019-11-06

    None

    更新日期:2020-01-04
  • ENC volume 46 issue 4 Cover and Back matter
    Environ. Conserv. (IF 2.759) Pub Date : 2019-11-06

    None

    更新日期:2020-01-04
  • A world in balance.
    Environ. Conserv. (IF 2.759) Pub Date : 1981-10-01
    A H Westing

    The objectives of this paper are to define the scope of global population growth within the uncompromising everyday realities of technology, economies, and politics and to demonstrate the intimate between the human population problem and the increasing problem of Nature's destruction. It is hoped that the human species will come to its sense in time to create an adequate standard of living of all of its members in peace and environmental balance. The number of people the world can support is considered in terms of 1) the provision for a standard of living adequate for everyone's health and wellbeing, 2) consideration for wildlife and nature, and 3) reliance on existing levels of technology and politics. Standards of living are suggested for the affluent and the austere. The focus on the discussion is on standards of living, global carrying capacity, the imperatives of population control and respect for nature, humans versus wildlife, and the need for a universal declaration of respect for nature. Carrying capacity is determined by total land area, cultivated land area, forest land area, cereals (grain), and wood. Use per capita of each of the 5 essentials is determined for the affluent or austere standard of living. An affluent standard means that world population would be limited to 2 billion, which is 50% of the current population. An austere standard of living means a limit of 3 billion, or 33% less than the existing population. The unfortunate reality is that today's total population of 4.5 billion is increasing at an annual rate of 1.9% and is not expected to level off until it has increased 3 times. This population growth occurs at the expense of wildlife. Of the total terrestrial animal biomass, humans constitute 4% and domestic livestock 15%, which, in 40 years, will reach a combined 40% and lead to more species extinction. One species of bird or mammal will become extinct for each increase of 220 million people, which happens every 3 years. The solution is a radical stop, reversal, and stabilization of population to achieve one which is lower than today's 4.5 billion.

    更新日期:2019-11-01
  • Forest-dweller demographics in West Kalimantan, Indonesia.
    Environ. Conserv. (IF 2.759) Pub Date : 1997-03-01
    J Fox,K Atok

    This study sought to ascertain, from census and other data, the number of people living on state-claimed forest land (SCFL) in West Kalimantan in the outer islands of Indonesia. One aim was to determine why data collection is problematic. In 1990 the outer islands accounted for 38% of total population, 93% of its land mass, and 98% of its forests. 72% of the land mass of the outer islands was designated SCFL. Kalimantan has 38.5 million hectares of SCFL, while West Kalimantan has 9.2 million hectares, or 63% of the land area of the province. In 1990, 3.2 million people lived in West Kalimantan. Two sets of forest cover maps and census statistics at the village level were integrated into the geographic information system (GIS) technology by district and regency boundaries and the location of villages. The fieldwork was conducted in Sengah Temila District in Pontianak Regency and Simpang Hulu District in Ketapang Regency. Four methods were used to estimate forest populations: 1) estimating gross population density, 2) mapping forest villages, 3) adjusting density to account for uneven population distribution, and 4) estimating population densities for specific villages and generalizing to the province level. Methods 3 and 4 gave the most reasonable estimates. Population varied from 650,000 to 1 million. Government census statistics proved to be accurate representations of human population. The 1:50,000 scale of topological maps of West Kalimantan correctly identified the location of villages listed in the census. The Indonesian Ministry of Forestry's forest-planning maps and the RePPProT maps both reported similar SCFL. The GIS technology was useful in integrating data from several sources. The lack of knowledge was not due to political or institutional interests.

    更新日期:2019-11-01
  • The fertility plateau in Costa Rica: a review of causes and remedies.
    Environ. Conserv. (IF 2.759) Pub Date : 1993-01-01
    K D Holl,G C Daily,P R Ehrlich

    Costa Rica achieved a substantial reduction in its overall fertility rate in a very short period of time. The halving of the fertility rate which occurred in less than ten years in Costa Rica transpired over the course of 100 years in France and 170 in Sweden. The level of contraceptive use in Costa Rica is twice that in other Central American nations. The authors summarize the recent demographic history of Costa Rica and review factors influencing its remarkable fertility decline. They then discuss possible explanations for the ensuing fertility plateau and conclude by suggesting strategies for affecting a further decrease in fertility rates. With regard to the reasons for the fertility plateau, cultural factors, socioeconomic factors, declining government commitment and family planning services, education, and the Church are considered. To reduce the level of fertility even further, the authors recommend that the government adopt a clear population policy which could serve as a basis for other changes such as increased support of family planning programs, improvements in the educational system, increased women's status and employment opportunities, and extensive education in schools and through the mass media on the socioeconomic and environmental effects of overpopulation. It is important to increase Costa Ricans' understanding of the negative impacts of continued population growth and the role of individual family planning decisions in that growth.

    更新日期:2019-11-01
  • Population, desertification, and migration.
    Environ. Conserv. (IF 2.759) Pub Date : 1994-07-01
    A H Westing

    When an imbalance develops between population numbers and the carrying capacity of the land, the persons thereby displaced are referred to as environmental refugees. The utilization of the land beyond sustainability leads to land degradation and ultimately, desertification. The social and political impacts of long-term environmental migration can be distinguished: a) at the site of origin of the displaced persons by the residual population; b) at rural sites of destination within the nation between the new arrivals and preestablished populations; c) in the cities within the nation; d) in the nonindustrialized foreign countries; and e) in the industrialized foreign countries. In the event that an area which had previously been devoted to pastoralism is converted to agriculture, the displaced pastoralists might respond through armed rebellion. In some instances, the disenchanted urban squatters become a politically restive and even a destabilizing force, as occurred in Sudan in the 1980s, especially in Khartoum and Port Sudan. The foreign countries to which many of the displaced persons are migrating are subjected to increasing levels of migrant-induced economic, cultural, and political strains. The growing problems associated with south-to-north migration across the Mediterranean Sea have recently led France, Italy, Portugal, and Spain to enter into a consultative arrangement with Algeria, Libya, Mauritania, Morocco, and Tunisia. All foreign aid to the nonindustrialized countries that attempts to ameliorate the problem of desertification must adopt integrated approaches that: a) address population issues; b) support environmental education; c) provide for the protection of biodiversity; d) encourage participatory forms of local and national government; e) provide opportunities for income generation outside the livestock sector; and f) foster political security and facilitate ecogeographical (subregional) cooperation.

    更新日期:2019-11-01
  • Population, environment, and development.
    Environ. Conserv. (IF 2.759) Pub Date : 1993-10-01
    N Myers

    The strategies for reducing population growth include social development and improvement in the educational attainment of women. The decline in Kenya's growth rate was attributed to high female literacy and reduced infant mortality. Another strategy for enhancing fertility decline is to reduce child mortality, particularly from preventable causes such as diarrhea. The entire cost of such a strategy to reduce preventable disease would be about $1.33 per 300 million taxpayers in developed countries. Family planning services must be expanded. Prevention of maternal mortality and AIDS would bring major benefits. Strategies for environmental protection emphasized the already existing plan of action set out in the UNCED document Agenda 21 in Rio de Janeiro. The plan has suffered from inaction. The estimated cost of $625 million was considered to be several times smaller than the costs of inaction. The elimination of subsidies in tropical forests would have an immediate impact. Natural resource accounting at the national level would include the value of natural resources. Pricing would change radically for gasoline if the costs of urban smog, acid rain, low-level ozone pollution, and global warming were taken into account. Strategies for sustainable development pertained to the preceding strategies and others indicated in the Agenda 21 Action Plan. If funding were better targeted to the poorest 20% of global population with high fertility rates, the accomplishments would be heralded. 1.2 million are living in absolute poverty, and aid for nutrition, primary health care, water and sanitation, basic education, and family planning amounts to only 10% of expenditures. An increase to 20% would mean a contribution from Americans of $7.50 per person or 33% of $25 thousand million from all developed countries. Developing countries need to lower their military expenditures, privatize public enterprises, change inappropriate development policies, eliminate corruption, and improve national governance. The debt burden should be reduced.

    更新日期:2019-11-01
  • Population crisis and desertification in the Sudano-Sahelian region.
    Environ. Conserv. (IF 2.759) Pub Date : 1984-07-01
    S Milas

    People living in the area just south of the Sahara Desert in Africa face their 3rd major drought since 1900. This drought brings about famine. Drought and famine are only manifestations of more profound problems: soil erosion and degradation. They diminish land productivity which aggravates the population's poverty. Yet soil erosion and degradation occur due to an expanding population. Continued pressures on the land and soil degradation results in desertification. The UN Environment Programme's Assessment of the Status and Trend of Desertification shows that between 1978-84 desertification spread. Expanding deserts now endanger 35% of the world's land and 20% of the population. In the thorn bush savanna zone, most people are subsistence farmers or herdsmen and rely on the soils, forests, and rangelands. Even though the mean population density in the Sahel is low, it is overpopulated since people concentrate in areas where water is available. These areas tend to be cities where near or total deforestation has already occurred. Between 1959-84, the population in the Sahel doubled so farmers have extended cultivation into marginal areas which are vulnerable to desertification. The livestock populations have also grown tremendously resulting in overgrazing and deforestation. People must cook their food which involves cutting down trees for fuelwood. Mismanagement of the land is the key cause for desertification, but the growing poor populations have no choice but to eke out an existence on increasingly marginal lands. Long fallow periods would allow the land to regain its fertility, but with the ever-increasing population this is almost impossible. Humans caused desertification. We can improve land use and farming methods to stop it.

    更新日期:2019-11-01
  • Rapid population growth and environmental degradation: ultimate versus proximate factors.
    Environ. Conserv. (IF 2.759) Pub Date : 1989-10-01
    R P Shaw

    This philosophical review of 2 arguments about responsibility for and solutions to environmental degradation concludes that both sides are correct: the ultimate and the proximal causes. Ultimate causes of pollution are defined as the technology responsible for a given type of pollution, such as burning fossil fuel; proximate causes are defined as situation-specific factors confounding the problem, such as population density or rate of growth. Commoner and others argue that developed countries with low or negative population growth rates are responsible for 80% of world pollution, primarily in polluting technologies such as automobiles, power generation, plastics, pesticides, toxic wastes, garbage, warfaring, and nuclear weapons wastes. Distortionary policies also contribute; examples are agricultural trade protection, land mismanagement, urban bias in expenditures, and institutional rigidity., Poor nations are responsible for very little pollution because poverty allows little waste or expenditures for polluting, synthetic technologies. The proximal causes of pollution include numbers and rate of growth of populations responsible for the pollution. Since change in the ultimate cause of pollution remains out of reach, altering the numbers of polluters can make a difference. Predictions are made for proportions of the world's total waste production, assuming current 1.6 tons/capita for developed countries and 0.17 tons/capita for developing countries. If developing countries grow at current rates and become more wealthy, they will be emitting half the world's waste by 2025. ON the other hand, unsustainable population growth goes along with inadequate investment in human capital: education, health, employment, infrastructure. The solution is to improve farming technologies in the 117 non-self-sufficient countries, fund development in the most unsustainable enclaves of growing countries, break institutionalized socio-political rigidity in these enclaves, and focus on educating and empowering women in these enclaves. Women are in charge of birth spacing and all aspects of management of energy, food, water and the local environment, more so than men, in most countries.

    更新日期:2019-11-01
  • Population change and environment in central and eastern Kenya.
    Environ. Conserv. (IF 2.759) Pub Date : 1990-07-01
    T E Downing,S Lezberg,C Williams,L Berry

    "This paper, in compiling a case-study of six districts in Central and Eastern Provinces of Kenya, addresses the two poles of theory regarding population, environment, and economy--restricted growth and degradation versus induced change and intensification. The paper presents data on population change, and explores its relevance for changing patterns of resource use and economic opportunity.... Changes in population density between the 1969 and 1979 censuses are compiled, using regions of agroclimatic potential as surrogates for indicators of economic development.... Trends in urbanization are also analysed, to illuminate the dynamics of rural-urban linkages."

    更新日期:2019-11-01
  • 更新日期:2019-11-01
  • Does Doing More Result in Doing Better? Exploring Synergies in an Integrated Population, Health and Environment Project in East Africa.
    Environ. Conserv. (IF 2.759) Pub Date : 2019-03-12
    Samuel Sellers

    Population, health and environment (PHE) projects are an increasingly popular strategy for addressing lack of access to healthcare and livelihood opportunities in settings with threats to biodiversity loss. PHE projects integrate services and messaging from different development sectors, including health (particularly family planning), conservation and livelihoods. However, a question remains: do such projects produce value-added outcomes; that is, synergistic effects as a result of integration across sectors? Using qualitative data to explore value-added outcomes resulting from a PHE project serving communities along Lake Victoria in Kenya and Uganda, this study explores several theories about why this integrated project may be generating value-added outcomes, including changes in established gender roles, as well as substitution of time and investment of new income into sustainable livelihood activities, particularly among women. Integration led to several value-added benefits, particularly for women, although long-term sustainability of project outcomes remains a key concern.

    更新日期:2019-11-01
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bug