This paper distinguishes three major "revolutions" in the socio-environmental interactions that reflect growth in the extent to which human beings invest in and modify their environments. As people settled in villages during the Neolithic, interactions between more people became an important element in survival strategies, shifting the emphasis in survival strategies from mobility to sociality. The emergence of cities changed human societies by: i) creating dependencies between more and more distant regions, ii) increasing the degree of aggregation of human populations, iii) narrowing the range of subsistence resources on which people depended, and iv) increasing further their investment in the natural environment and in material culture. Altogether, urbanization drove human social systems further and further away from flexibility and rapid adaptation to environmental change, while increasing the demands on the social system, including major increases in energy and matter to support urban populations. This was achieved by linking together larger and larger hinterlands for these cities, in effect creating Empires. The fundamental change is one from humans responding to environmental change and disruption by migration to humans investing in the environment, and therefore responding to environmental change by problem solving. One therefore needs to look at the combined socio-environmental systems over the longer term that reflect the buildup and culmination of the shifts in the social and environmental risk spectra due to the human-environmental interactions in periods before the "crisis" occurs, which are a fact of life in any society's interaction with its environment, and should be seen as "social" challenges rather than "environmental" ones. These are generally due to the fact that the society in question has invested so much in a particular way of life that it cannot innovate itself out of difficulty before time runs out. This implies that we have to shift our thinking about socio-environmental issues, from "population thinking" to "organization thinking." In this perspective, a crisis does not imply the disappearance of the people involved, but a transformation of the organization that links them.
Anthropogenic deforestation has shaped ecosystems worldwide. In subarctic ecosystems, primarily inhabited by native peoples, deforestation is generally considered to be mainly associated with the industrial period. Here we examined mechanisms underlying deforestation a thousand years ago in a high-mountain valley with settlement artifacts located in subarctic Scandinavia. Using the Heureka Forestry Decision Support System, we modeled pre-settlement conditions and effects of tree cutting on forest cover. To examine lack of regeneration and present nutrient status, we analyzed soil nitrogen. We found that tree cutting could have deforested the valley within some hundred years. Overexploitation left the soil depleted beyond the capacity of re-establishment of trees. We suggest that pre-historical deforestation has occurred also in subarctic ecosystems and that ecosystem boundaries were especially vulnerable to this process. This study improves our understanding of mechanisms behind human-induced ecosystem transformations and tree-line changes, and of the concept of wilderness in the Scandinavian mountain range.
This study was conducted in the Swedish subArctic, near Abisko, in order to assess the direction and scale of possible vegetation changes in the alpine-birch forest ecotone. We have re-surveyed shrub, tree and vegetation data at 549 plots grouped into 61 clusters. The plots were originally surveyed in 1997 and re-surveyed in 2010. Our study is unique for the area as we have quantitatively estimated a 19% increase in tree biomass mainly within the existing birch forest. We also found significant increases in the cover of two vegetation types--"birch forest-heath with mosses" and "meadow with low herbs", while the cover of snowbed vegetation decreased significantly. The vegetation changes might be caused by climate, herbivory and past human impact but irrespective of the causes, the observed transition of the vegetation will have substantial effects on the mountain ecosystems.
Many migratory bird species have advanced their spring arrival during the latest decades, most probably due to climate change. However, studies on migratory phenology in the period before recent global warming are scarce. We have analyzed a historical dataset (1873-1917) of spring arrival to southern and central Sweden of 14 migratory bird species. In addition, we have used relative differences between historical and present-day observations (1984-2013) to evaluate the effect of latitude and migratory strategy on day of arrival over time. There was a larger change in spring phenology in short-distance migrants than in long-distance migrants. Interestingly, the results further suggest that climate change has affected the phenology of short-distance migrants more in southern than in central Sweden. The results suggest that the much earlier calculated arrival to southern Sweden among short-distance migrants mirrors a change in location of wintering areas, hence, connecting migration phenology and wintering range shifts.
A study was conducted to evaluate long-term trends in nitrate concentrations and to try to identify the origin of nitrate using stable isotopes (15N(NO3-) and 18O(NO3-)) in the aquifers of the western Central Valley, Costa Rica, where more than 1 million people depend on groundwater to satisfy their daily needs. Data from 20 sites periodically sampled for 4 to 17 years indicate an increasing trend in nitrate concentrations at five sites, which in a period ranging from 10 to 40 years, will exceed recommended maximum concentrations. Results of isotopic analysis indicate a correspondence between land use patterns and the isotopic signature of nitrate in groundwater and suggest that urbanization processes without adequate waste disposal systems, followed by coffee fertilization practices, are threatening water quality in the region. We conclude that groundwater management in this area is not sustainable, and that land use substitution processes from agricultural activity to residential occupation that do not have proper sewage disposal systems may cause a significant increment in the nitrate contaminant load.
Conservation of the marine environment mainly focuses on threatened elements and more precisely on vulnerable and endangered species like birds and mammals. When dealing with the conservation of marine habitats, the scientific community is mainly interested in hot spots of diversity, like seagrass beds in Europe, or hot spots of endemism, like coral reefs in tropical areas. Nevertheless, using the example of a common and widespread marine invertebrate, the sandmason worm (Lanice conchilega, Polychaeta, Terebellidae), we show that vulnerability and rarity are not the only criteria to take into account in order to select the best natural element for conservation. This species can form dense beds that increase biodiversity, are attractive feeding grounds for birds and fishes, and have a high socioeconomic value. In consequence, they have a high functional value that should be considered as an important conservation stake. Through the example of the Chausey archipelago and the Bay of the Mont Saint-Michel (France), we propose a synthetic interdisciplinary approach to evaluate the conservation needs of these beds. The issue is even more pressing when one considers that these natural elements and many similar ones still do not benefit from any legal protection in Europe despite their high heritage value.
News accounts both reflect and influence public opinion through their noted 'agenda-setting' capability. We examined newspaper articles in Australia's The Sydney Morning Herald from 1843 to 2011 to observe the evolution of media coverage on water issues related to water resources management. The results showed that water supply-related articles have dominated the reporting of water issues since 1843. This emphasis is reflected in the institutions involved and their related policy/management initiatives, as well as the themes of the articles. Extreme events such as flooding and drought have punctuated the historical record of reports on water issues. An economic development-driven tone was overwhelmingly predominant in newspaper articles (85 % of the total); however, there has been a marked decline in the importance of development-driven tone relative to environmental-sustainability oriented tone of articles since 1994. People from academia and NGOs were rarely quoted. Inclusion of wider range stakeholders should be considered as a strategic break-through and natural events should be considered as an "opportunity" to change public opinion on water issues for environmental sustainability.
We relate the historical (1850-2000) spatial and temporal changes in cropland cover in the conterminous United States to several socio-economic and biophysical determinants using an eco-region based spatial framework. Results show population density as a major determinant during the nineteenth century, and biophysical suitability as the major determinant during the twentieth century. We further examine the role of technological innovations, socio-economic and socio-ecological feedbacks that have either sustained or altered the cropland trajectories in different eco-regions. The cropland trajectories for each of the 84 level-III eco-regions were analyzed using a nonlinear bi-analytical model. In the Eastern United States, low biophysically suitable eco-regions, e.g., New England, have shown continual decline in the cropland after reaching peak levels. The cropland trajectories in high biophysically suitable regions, e.g., Corn Belt, have stabilized after reaching peak levels. In the Western United States, low-intensity crop cover (<10 %) is sustained with irrigation support. A slower rate of land conversion was found in the industrial period. Significant effect of Conservation Reserve Program on planted crop area is found in last two decades (1990-2010).
In this study, a consistent basin-wise monthly time series of the atmospheric nutrient load to the Baltic Sea during 1850-2006 was compiled. Due to the lack of a long time series (1850-1960) of nutrient deposition to the Baltic Sea, the data set was compiled by combining a time series of deposition data at the Baltic Nest Institute from 1970 to 2006, published historical monitoring data and deposition estimates, as well as recent modeled Representative Concentration Pathways (RCP) emission estimates. The procedure for nitrogen compounds included estimation of the deposition in a few intermediate reference years, linear interpolation between them, and the decomposition of annual deposition into a seasonal deposition pattern. As no reliable monitoring results were found for the atmospheric deposition of phosphorus during the early period of our study, we used published estimates for the temporal and spatial pattern of the phosphorus load.
The study examines the history of strategic decision-making concerning water protection in Helsinki, 1850-2000. We identified five major strategic decisions that occurred during the study period. The results indicate that strategic decision-making evolves in long-term policy cycles that last on average 20-30 years. New policy cycles are caused by paradigm shifts. Paradigms are shared and predominant ways of understanding reality that help when groups must act to solve common and complex environmental problems. However the internal structure and external dynamics of paradigms are contradictory. Although paradigms serve initially as means to redefine problems and find creative solutions, as time goes by each paradigm seems to become also a barrier that restricts the introduction of new ways of thinking and acting. The power of paradigms lies in the fact that they can be defined as scientific but also social, political, or cultural agreements depending on the context.
A comprehensive reconstruction of the Baltic Sea state from 1850 to 2006 is presented: driving forces are reconstructed and the evolution of the hydrography and biogeochemical cycles is simulated using the model BALTSEM. Driven by high resolution atmospheric forcing fields (HiResAFF), BALTSEM reproduces dynamics of salinity, temperature, and maximum ice extent. Nutrient loads have been increasing with a noteworthy acceleration from the 1950s until peak values around 1980 followed by a decrease continuing up to present. BALTSEM shows a delayed response to the massive load increase with most eutrophic conditions occurring only at the end of the simulation. This is accompanied by an intensification of the pelagic cycling driven by a shift from spring to summer primary production. The simulation indicates that no improvement in water quality of the Baltic Sea compared to its present state can be expected from the decrease in nutrient loads in recent decades.
This article focuses on the emergence of water pollution problems in the city of Malmö and on how they were discussed and solved. Various countermeasures were proposed and considered, but finally the discharge of wastewater into the Sound of Oresund was regarded as the best solution. As a result, a local pollution problem was transformed into a regional issue. The solutions adopted in Malmö are briefly compared with decisions made in Gothenburg and Stockholm.
The changes in the vascular plant flora of Tasiilaq, low arctic southeast Greenland, between around 1900 and 2007 were studied by comparing the data from historical literature with those of the field observations performed between the late 1960s and 2007. Since 1900, the percentage of widely distributed arctic species distinctly decreased, whereas that of the low arctic species somewhat increased, and boreal species hardly increased. Vegetation monitoring revealed minor changes and showed that several thermophilous and xerophilous species increased between 1968/1969 and 2007, whereas some hygrophilous species decreased. Repeated vegetation mapping of a shallow pond revealed conspicuous changes suggesting increased evaporation/precipitation ratios associated with environmental warming up and decreasing snow accumulation in winter, in line with results of previous investigations. In spite of climate warming, expansion of the town and increasing human impact, flora and vegetation on the whole appeared rather stable during the last 40 years without invading species or introductions.
This report presents the current dynamics of the natural environment and landscape in a part of the mountainous southeastern Spitsbergen coast on the Barents Sea in 1900-2005. Its current state substantially varies from what is shown on recently published topographic maps actual for 1936. The physico-geographical mapping and GPS survey were the basic field methods of recognizing the area, supplemented by remote sensing. Each landscape component, except for the Pre-Quaternary bedrock, has been changed primarily as a direct or indirect result of the current warming. The most dramatic landscape transformation has been connected with the formation of a fjord, the abandoning of the lower parts of valleys by tidewater glaciers, and the alteration of the coastline. This transformation's pace has been increasing visibly over the last few decades. The landscape became more diversified. There is a positive feedback in the process of life expansion in the study area: the processes of animal colonization and plant succession stimulate each other.
The postwar development of water protection legislation and wastewater discharges is poorly known for the Baltic Sea region as a whole. This article presents national efforts to govern wastewater discharges in Poland using legal tools over the twentieth century with an emphasis on the postwar period, 1945-2003. The study also attempts to evaluate how the state authority responded to changing legal demands in terms of urban and industrial wastewater discharges in the postwar period. It outlines the main changes during the socialist regime in Poland and after it regained independence. Also the implications of Poland's integration into the European Union are briefly discussed. Mathematical calculations are used to illustrate some changes in legal requirements over time.
The Lithuanian water-management system developed on the basis of Soviet regulations in 1950-1990. Surface-water quality monitoring started in the 1950s, and the system was improved in the 1960s. Today, 48 rivers are being monitored using up to 70 parameters. Statutory monitoring of discharges started in 1962, wastewater standards were issued in 1957 and 1966, and then revised in 1996. Wastewater-treatment plants were built first in rural areas, in factories since the 1950s, and later in towns. Since 1991, large capacity municipal plants have been constructed with foreign assistance. Water quality has improved in some rivers since 1970, but Lithuania's main river, Nemunas, remains moderately polluted. The lower Nemunas is especially affected by discharges of municipal and industrial wastewater from Sovietsk and Neman (Russia), which account for half of the total loading. Hydrobiological data of 1994-1998 indicated the eutrophication of the Curonian Lagoon, and bacteriological pollution and blue-green algae blooms in the Baltic Sea north of Klaipeda.
Results of research into climate and glacier dynamics in the Altai Mountains (Russia) over the period of instrumental observations (1952-2008) are presented in this article. About 1030 glaciers with a total area of 805 km2 and volume of 42.5 km3 have been recorded in the Altai Region. The average summer air temperature in different regions of the Altai has increased during the study period from about 0.2 degrees C (Aktru) to 1.1 degrees C (Akkem). The annual atmospheric precipitation rate has also increased, by 8-10%. Since 1952, the glacier area in different regions of the Altai has decreased by 9-27%, and volume by 12-24%. By 2008, as a result of degradation, the total number of glaciers was 953 with an area of 724 km2 and volume of 38 km3.
Extreme daily precipitation in Sweden for the years 1961-2000 is analyzed with respect to spatial scale, regional variations and associated weather types. Correlograms based on a lag distance of 30 km estimated the spatial scale of variation of the annual mean precipitation, the 99th percentile of daily precipitation and the average of annual maximum daily precipitation to 100 km, 60-100 km and 40-70 km, respectively. Regions of correlation with respect to precipitation at 82 stations during days of extreme events are identified through Maximum-Likelihood Factor Analysis. Eleven factors are found to provide the optimum factor solution. Weather types for the days of extreme events are determined by an objective classification scheme, based on daily sea level pressure, which is modified by subjective inclusion of fronts. In total, 63% of the extreme events occurred during cyclonic weather types, 32% during frontal, 3% during directional and 2% during anticyclonic types. The frequency of the weather types during extreme events varied between the regions however.
Nitrogen inputs to the US from human activity doubled between 1961 and 1997, with most of the increase in the 1960s and 1970s. The largest increase was in use of inorganic N fertilizer, but emissions of NOx from fossil-fuel combustion also increased substantially. In 1961, N fixation in agricultural systems was the largest single source of reactive N in the US. By 1997, even though N fixation had increased, fertilizer use and NOx emissions had increased more rapidly and were both larger inputs. In both 1961 and 1997, two thirds of reactive N inputs were denitrified or stored in soils and biota, while one third was exported. The largest export was in riverine flux to coastal oceans, followed by export in food and feeds, and atmospheric advection to the oceans. The consumption of meat protein is a major driver behind N use in agriculture in the US Without change in diet or agricultural practices, fertilizer use will increase over next 30 years, and fluxes to coastal oceans may increase by another 30%. However, substantial reductions are possible.
The tail feathers of 104 osprey nestlings (Pandion haliaetus) from Lake Asnen, southern Sweden, were analyzed for total mercury and selenium content. Concentrations of mercury in feathers from the western part of the lake fell during the period 1969-1998, when pollution from industrial mercury had decreased and a paper mill upstream of the lake was closed down in 1979. Nestlings from the eastern part of the lake had initially lower levels of mercury, predominantly from atmospheric fallout. The levels did not decrease during the period. The reason for the differences seems to be the limited water flow between the western and the eastern part of the lake. The selenium concentrations were constant over time and approximately the same in both parts of the lake. The total-Hg/Se ratio in the western part of the lake was 2.94, which is somewhat higher than the 1:1 molar ratio constant (2.54). This indicates that the bioaccumulated quantity of selenium which is thought to be protective for the organisms against the toxic effects of mercury, is somewhat insufficient to bind all body mercury.
Global trends of increasing rural-urban migration and population urbanization could provide opportunities for nature conservation, particularly in regions where deforestation is driven by subsistence agriculture. We analyzed the role of rural population as a driver of deforestation and its contribution to urban population growth from 1970 to the present in the Atlantic Forest of Argentina, a global conservation priority. We created future land-use-cover scenarios based on human demographic parameters and the relationship between rural population and land-cover change between 1970 and 2006. In 2006, native forest covered 50% of the province, but by 2030 all scenarios predicted a decrease that ranged from 18 to 39% forest cover. Between 1970 and 2001, rural migrants represented 20% of urban population growth and are expected to represent less than 10% by 2030. This modeling approach shows how rural-urban migration and land-use planning can favor nature conservation with little impact on urban areas.
We investigated unhatched eggs (n = 57) of Goshawks (Accipiter gentilis) from the period 1988--2002 and compared them with eggs (n = 134) from 1971--1978. Mean concentrations of PCBs, sigmaDDT and HCB in the earlier period were (mg kg(-1) lipid weight) 50.1, 126.6, and 117.7, while the values from the later period were statistically significantly lower: 27.7, 4.1, 0.1, respectively. Nevertheless, the concentration of PCB is relatively constant during the last 8-10 years. The variability of residues was lower within clutches than among clutches. No age-dependent accumulation in eggs could be demonstrated. A statistically significant lower shell index was measurable for the period 1971--1978, while this index during 2001--2002 was relatively high as it was during the late 18th century. We are suggesting a threshold value for effect concentrations on shell index. Residues of the DDT-group had an influence on the number of fledged young per nest site.
Despite reductions in atmospheric SO4(2-) deposition and resultant decreases in surface water acidity, widespread biological recovery from acidification has not yet been documented. Temporal trends in crustacean zooplankton species richness (number of species) and composition were examined between 1971-2000 in 46 Killarney Park lakes, Ontario, Canada, to assess the degree of biological recovery in lakes with significant water quality improvements, i.e. pH now > 6, compared to 2 other groups: i) lakes which never acidified; and ii) lakes which are still acidified (pH < 6). Time trends in species richness could not be distinguished among the 3 groups of lakes, nor did changes in species richness indicate recovery. In contrast, the zooplankton community composition of lakes in which the pH increased to above 6, as measured by a multivariate index of species abundances, changed from a "damaged" state to one typical of neutral lakes. Some recovery in composition was also documented for the acidic lakes. While still acidic, the pH levels of these lakes have risen. The extent and pace of recovery in Killarney Provincial Park bodes well for the future of other acidified regions in North America and Europe.
Urban metabolism measures quantitatively a city's load on the natural environment. We update the Newcombe et al. (3) pioneering study of Hong Kong's urban metabolism in 1971, highlighting trends in resource consumption and waste generation. Per capita food, water and materials consumption have surged since the early 1970s by 20%, 40%, and 149%, respectively. Tremendous pollution has accompanied this growing affluence and materialism, and total air emissions, CO2 outputs, municipal solid wastes, and sewage discharges have risen by 30%, 250%, 245%, and 153%. As a result, systemic overload of land, atmospheric and water systems has occurred. While some strategies to tackle deteriorating environmental quality have succeeded, greater and more far-reaching changes in consumer behavior and government policy are needed if Hong Kong is to achieve its stated goal of becoming "a truly sustainable city" in the 21st century.
The inundated area of the Okavango Delta changes annually and interannually. The variability relates to regional precipitation over the catchment area in the Angolan highlands, and to local rainfall. The patterns of the wetland were captured using more than 3000 satellite images for the period 1972 to 2000, near daily NOAA AVHRR data for 1985-2000, and less frequent images of the Landsat sensors from 1972 onwards. One AVHRR image for every 10-day period was classified into land and water using an unsupervised classification method. Evaluation against Landsat TM and ERS2-ATSR data indicate an agreement of 89% for the size of estimated inundation area. Results show that the wetland area has varied between approximately 2450 km2 and 11400 km2 during the last 30 years.
The following paper analyzes the economic and demographic factors determining the conversion of mangroves in the coastal provinces of Thailand to commercial shrimp farming. Mangrove conversion therefore is determined by the returns to shrimp farmers, (i.e. the price of shrimp), the input costs to farming shrimp (e.g. feed price and wages) and the "accessibility" of mangrove areas. Additional exogenous influences, such as income per capita, population growth, and in-migration (i.e. the number of shrimp farms) also are important. Both a mangrove conversion and a shrimp farm expansion relationship are estimated empirically through a panel analysis across 21 coastal provinces of Thailand between 1979-1996. Results show that the price of shrimp, minimum wage, distance from market, feed price, population growth, income per capita, and shrimp-farm density all have important influences on mangrove loss due to shrimp farming in Thailand.
This study is focused on the global expansion of protected-area coverage that occurred during the 1980--2000 period. We examine the multi-scale patterning of four of the basic facets of this expansion: i) estimated increases at the world-regional and country-level scales of total protected-area coverage; ii) transboundary protected areas; iii) conservation corridor projects; and iv) type of conservation management. Geospatial patterning of protected-area designations is a reflection of the priorities of global conservation organizations and the globalization of post-Cold War political and economic arrangements. Local and national-level factors (political leadership and infrastructure) as well as international relations such as multilateral and bilateral aid combine with these globalization processes to impact the extent, type, and location of protected-area designations. We conclude that the interaction of these factors led to the creation and reinforcement of marked spatial differences (rather than tendencies toward worldwide evenness or homogenization) in the course of protected-area expansion during the 1980--2000 period.
Long-term changes in the environmental quality of water in Latvia (chemical composition of inland waters, wastewater treatment, and drinking-water treatment practices and quality) as a response to socioeconomic changes have been studied. Water composition, the major factors influencing water chemistry, and human impacts (wastewater loading) were studied to determine changes that occurred after recent reductions in pollution emissions, particularly nutrient loading, to surface waters. After 1991, (Latvia regained independence in 1991) inland water quality has begun to improve mainly as a result of decreases in nutrient loads from point and nonpoint sources and substantial efforts in the area of environmental protection. The situation differs, however, for drinking-water treatment, where practices have also changed during the whole period from 1980 till 2000. More stringent drinking-water-quality standards and novel insights regarding changes in water quality in the distribution network, necessitate further improvements in public water supply, and place this particular water issue among Latvia's main priorities.
Amazonian deforestation rates vary regionally, and ebb and flow according to macroeconomic policy and local social factors. We used remote sensing and field interviews to investigate deforestation patterns and drivers at a Peruvian frontier during 1986-1991, when rural credit and guaranteed markets were available; and 1991-1997, when structural adjustment measures were imposed. The highest rate of clearing (1.5% gross) was observed along roads during 1986-1991. Roadside deforestation slowed in 1991-1997 (0.7% gross) and extensive regrowth yielded a net increase in forest cover (0.5%). Deforestation along rivers was relatively constant. Riverside farms today retain more land in both crops and forest than do roadside farms where pasture and successional growth predominate. Long-term residents maintain more forest on their farms than do recent colonists, but proximity to urban markets is the strongest predictor of forest cover. Future credit programs must reflect spatial patterns of development and ecological vulnerability, and support the recuperation of fallow lands and secondary forest.
This study uses life-cycle analysis to examine the net greenhouse gas (GHG) emissions from the Canadian peat industry for the period 1990-2000. GHG exchange is estimated for land-use change, peat extraction and processing, transport to market, and the in situ decomposition of extracted peat. The estimates, based on an additive GHG accounting model, show that the peat extraction life cycle emitted 0.54 x 10(6) t of GHG in 1990, increasing to 0.89 x 10(6) t in 2000 (expressed as CO2 equivalents using a 100-y time horizon). Peat decomposition associated with end use was the largest source of GHGs, comprising 71% of total emissions during this 11-y period. Land use change resulted in a switch of the peatlands from a GHG sink to a source and contributed an additional 15%. Peat transportation was responsible for 10% of total GHG emissions, and extraction and processing contributed 4%. It would take approximately 2000 y to restore the carbon pool to its original size if peatland restoration is successful and the cutover peatland once again becomes a net carbon sink.
Nighttime satellite photographs of Earth reveal the location of lighting and provide a unique view of the extent of human settlement. Nighttime lights have been shown to correlate with economic development and population but little research has been done on the link between nighttime lights and population change over time. We explore whether population decline is coupled with decline in lighted area and how the age structure of the population and GDP are reflected in nighttime lights. We examine Europe between the period of 1992 and 2012 using a Geographic Information System and regression analysis. The results suggest that population decline is not coupled with decline in lighted area. Instead, human settlement extent is more closely related to the age structure of the population and to GDP. We conclude that declining populations will not necessarily lead to reductions in the extent of land development.
The global urban population is increasing rapidly, but patterns of urban expansion differ greatly among countries. Urban transition theory predicts that the shift from low to high urbanization depends on a country’s history and level of economic development. This study describes urban expansion in Colombia, Ecuador, Peru, and Bolivia between 1992 and 2009. Urban dynamics were analyzed by combining nighttime lights and census data from 4032 municipalities. High-lit areas (>52–63 pixel values) were correlated with urban populations across municipalities and years (R
2 > 0.90). Analyses showed that between 1992 and 2009 Bolivia and Ecuador had rapid population growth and rapidly increasing high-lit areas, while Peru and Colombia had lower rates of population growth and urbanization (i.e., expansion of high-lit areas). We demonstrate how nighttime lights can be a useful tool, providing a homogeneous platform for multi-scale analyses of urban growth.
Data were collected in southern Kenya on coral reef ecosystems and fisheries to assess the influence of the 1998 coral bleaching and mortality event. We compared benthic cover, sea urchin and fish abundance in unfished marine parks and fished reefs and the reef-associated fisheries 3 years before and after 1998. Hard and soft coral decreased while coralline algae increased in both management areas. Turf increased in marine parks and sponge and fleshy algae increased in the fished reefs. Sea urchin grazer biomass was unchanged over this period and the fish community changed less than benthic cover. In general, butterflyfish, damselfish and wrasses were negatively influenced while surgeonfish and a few uncommon families were positively influenced by the substratum change. There was a 17% increase in fishing effort as measured by fishermen per day at each landing site and the total demersal catch declined by 8% and the catch per man declined by 21% after 1998. The decline in the total catch and CPUE combined with the increase in effort suggest an overexploited fishery and this makes it difficult to distinguish changes caused by coral mortality or fishing effort. The price of fish increased over this period and this caused an 18% increase in the total value of the fishery but no difference in the net income of individual fishermen.
Three years after most corals died on the central Indian Ocean reefs of Chagos, erosion and recovery were studied to 30 m depth. Mortality was near-total to 15 m deep in northern atolls, and to > 35 m in central and southern atolls. Some reef surfaces have 'dropped' 1.5 m due to the loss of dense coral thickets. Coral bioerosion is substantial, reducing 3-D reef 'structure' and forming unconsolidated rubble. Juvenile corals are abundant, though mostly on eroding or unstable substrates, and are of less robust species. Reef fish abundance and diversity at 15 m depth remains high; species dependent on corals have diminished, while some herbivores and detritivores have increased. A new sea surface temperature (SST) data set shows that mean SST has risen 0.65 degree C since 1950. The critical SST causing the mortality in Chagos was 29.9 degrees C.
Inhaca Island, southern Mozambique, is located towards the southerly latitudinal limits of coral reef growth. Reef development is restricted to the margins of channels which dissect intertidal flats on the Maputo Bay side of the island, and to depths of around 6 m. In contrast to lower latitude reefs, reef development is therefore both spatially and bathymetrically restricted (largely due to high turbidity levels). These natural stress levels were exacerbated, via increased freshwater and sediment discharge, during the severe floods of late 1999/early 2000. Flood impacts varied but were most significant on reefs on the inner (western) side of the island where live coral cover (LCC) decreased from 60.5% (1999) to 24.0% (2001). This is attributed to freshwater-induced bleaching. Dead in situ coral cover increased from 18.6% (1999) to 51.3% (2001). Reefs on the southern tip of the island, by contrast, were relatively unaffected. It is suggested that this largely reflects a closer proximity to the open Indian Ocean which mitigated the effects of freshwater dilution.
An experiment combining the use of two ecosystem models was conducted to search for effective protection strategies for the Gulf of Finland (Baltic Sea). Reference and scenario simulations were first run with a one-dimensional (1D) model for seven main basins of the entire Baltic Sea until steady state was achieved. The obtained basinwise distributions of inorganic nitrogen (N) and phosphorus (P), as well as sediment labile P, were then used to initiate 5-y simulations with a three-dimensional (3D) ecosystem model. The results suggest that relatively small local load reductions (the "Finland" scenario) would improve only the state of adjacent coastal waters significantly. This would be the case, even for runs covering several decades, which clearly exceed the residence times of nutrients in the Gulf of Finland. A significant decrease from a substantial loading source to the Gulf (the "St. Petersburg" scenario) would decrease cyanobacterial biomasses in the entire Gulf of Finland and also immediately outside it. A reduction in the current Polish nutrient loads would improve the situation in the whole Baltic Proper and cause an extensive decline in cyanobacterial biomasses in the Gulf of Finland, as well. However, it would take several decades until the improvement caused by reducing loads in the "Poland" scenario is seen, while in the "St. Petersburg" scenario the corresponding time lag would only be a few years. Our results suggest that the common water protection policy in the Baltic Sea region should have the largest nutrient sources as its primary target, regardless of their location and country.
This paper examines the impact of food and energy production on the global N cycle by contrasting N flows in the late-19th century with those of the late-20th century. We have a good understanding of the amounts of reactive N created by humans, and the primary points of loss to the environment. However, we have a poor understanding of nitrogen's rate of accumulation in environmental reservoirs, which is problematic because of the cascading effects of accumulated N in the environment. The substantial regional variability in reactive nitrogen creation, its degree of distribution, and the likelihood of increased rates of reactive-N formation (especially in Asia) in the future creates a situation that calls for the development of a Total Reactive Nitrogen Approach that will optimize food and energy production and protect environmental systems.
Modern concerns with climate change often overlook the extensive history of both climate change and human adaptation over the millennia. While questions of human-climate system causation are important, especially to the extent that our current behavior is driving environmental change, human societies have experienced multiple climate changes in the past, independent of causation. The histories of cultural adaptation to those changes can help us understand the dynamic interaction between climate and society, expanding the possibilities for "proactive adaptation" that may be available to us today. The underlying principles of cultural adaptation are generally independent of the source of the climate change, and the lessons of the past can suggest social and economic paths that can lead toward sustainability and away from collapse.
During the extreme dry year of 2006, abnormal salinity conditions in the Changjiang Estuary of the Yangtze River occurred in partial coincidence with the second impoundment phase of the TGD (Three Gorges Dam). Analysis of discharge observations in the upper reaches of the estuary and of salinity observations in the estuary as a whole reveals that in 2006 salinity was over 100 mg/l during 275 days, over 250 mg/l during 75 days and over 400 mg/l during 48 days. It is well known that this is due to extreme low discharges from the upper catchment area into the estuary. Moreover, large amounts of water consumed along the lower reaches of the Yangtze River can also aggravate the low discharges that lead to stronger saltwater intrusion in the estuary. Of the 75 days that salinity was over 250 mg/l, the low discharge was decreased further by 10 to 20% due to water consumption. The additional impact of the impoundment phase of the TGD (lasting 37 days in autumn) was noticeable only during 7 days in 2006. During that period, the relative contributions of the TGD and the water consumption in the lower reaches of the Yangtze River amounted to 70 and 30%, respectively. It may be concluded that the impact of the second impoundment phase of the TGD on salinity intrusion in the estuary was modest, while the extreme drought of 2006 was the dominant cause.
This study addresses the exhaust emissions of CO2, NOx
, CO, and PM2.5 originated from Baltic Sea shipping in 2006–2009. Numerical results have been computed using the Ship Traffic Emissions Assessment Model. This model is based on the messages of the automatic identification system (AIS), which enable the positioning of ships with a high spatial resolution. The NOx
emissions in 2009 were approximately 7 % higher than in 2006, despite the economic recession. However, the SOx
emissions in 2009 were approximately 14 % lower, when compared to those in 2006, mainly caused by the fuel requirements of the SOx
emission control area (SECA) which became effective in May 2006, but affected also by changes in ship activity. Results are presented on the differential geographic distribution of shipping emissions before (Jan–April 2006) and after (Jan–April 2009) the SECA regulations. The predicted NOx
emissions in 2009 substantially exceeded the emissions in 2006 along major ship routes and at numerous harbors, mostly due to the continuous increase in the number of small vessels that use AIS transmitters. Although the SOx
emissions have been reduced in 2009 in most major ship routes, these have increased in the vicinity of some harbors and on some densely trafficked routes. A seasonal variation of emissions is also presented, as well as the distribution of emissions in terms of vessel flag state, type, and weight.
Conservation policies are increasing in response to human-induced ecosystem degradation, but little is known about their interplay with natural disasters. Through an analysis of satellite imagery and field data we evaluated the impacts of a devastating earthquake on forest recovery and avoided forest loss estimated to have been obtained by two of the largest conservation programs in the world. Results show that more than 10% of the forests in Wenchuan County, Sichuan province, China were immediately affected by the 2008 earthquake, offsetting some gains in forest cover observed since the enactment of the conservation programs. But without the enactment of these conservation programs, the combined effects of human disturbance and earthquake-induced landslides could have severely reduced the region's forest cover. The continuation--and enhancement--of incentives for participation in conservation programs will be important for reducing the environmental impacts of the combined effects of human disturbance and natural hazards not only in the study area but also in many disaster-prone regions around the world.
Development of effective indicators is indispensable for countries and societies to monitor effects of their actions on biodiversity, as is recognized in decision VI/26 of the Convention on Biological Diversity. Good indicators would ideally be scalable, at least for the different scales that characterize biodiversity patterns and process. Existing indicators are mostly global in scope, and often based on secondary information, such as classifications of endangered species, rather than on primary data. We propose a complementary approach, based on the increased availability of raw data about occurrences of species, cutting-edge modeling techniques for estimating distributional areas, and land-use information based on remotely sensed data to allow estimation of rates of range loss for species affected by land-use conversion. This method can be implemented by developing countries, given increasing availability of data and the open and well-documented nature of the techniques required.
The SoA conference emphasized that urgent questions posed by society and decision-makers in response to rapid Arctic change require that Arctic research address the broader concepts of sustainability as well as adaptation to and mitigation of interrelated environmental and socioeconomic change. Murray et al. (submitted) explore progress made in this context. The SoA meeting demonstrated significant progress by the Arctic community of scientists and stakeholders in meeting this challenge, as well as the need to better engage the private sector and find more effective ways to partner with relevant research activities outside of the polar regions.
Comment to: Svensson, C. J., A. Eriksson, T. Harkonen and K. C. Harding. 2011. Detecting density dependence in recovering seal populations. AMBIO 40:52–59.
A recent simulation study (Svensson et al. 2011) proposed the use of changes in age-structure as an indicator of density dependent effects on the growth of the Baltic grey seal (Halichoerus grypus) population. That approach provides a clever alternative to the direct examination of abundance estimates, and sidesteps the well-known difficulty of detecting trends in marine mammal populations from survey data (Taylor et al.2007). However, there are three features of Svensson et al.’s analysis that limit its utility as a demonstration of the practicality of their methodology as a tool for investigating real-world problems.