54 research outputs found
Rivers in Contention: Is There a Water War in South Asiaâs Future?
Rivalry over river water resources has been a constant theme in the international politics of the South Asian region ever since the British Raj ended in 1947. Indeed, hardly had independence been gained when the competing claims of India and Pakistan to the waters of the Indus river basin helped bring on the first war between them over Kashmir (1947-1949). Nearly a decade of arduous World Bank-facilitated negotiations resulted finally in the 1960 Indus Waters Treaty (IWT), a landmark agreement that succeeded in resolving the question of Indus waters ownership by getting Indian and Pakistani consent to the permanent division of the six rivers of the Indus system. That formula, perhaps suitable enough for then, strikes some as an ill fit for now. After all, much has changed in the sixty-odd years that have passed since independence. The South Asian region has experienced more than a tripling of its population; and it has also undergone the massive social and economic changes that go along with industrialization and urbanization. Inevitably, these things have brought it under vastly increased pressures on water availability for agricultural and other uses. Acute fresh water scarcity now ranks among the most pressing domestic problems faced by Pakistan, and it is scarcely less pressing for large parts of India and Bangladesh as well. Exacerbated by equally acute power shortages in these countries (a development attracting attention to the regionâs vast hydroelectric potential), their water resource-related disputes are already among the most nettlesome issues on their bilateral agendas. This is no less true of India-Bangladesh relations, which are bedeviled by the failure of their governments to seal water sharing agreements on any but one of the 54 rivers India and Bangladesh share in common, than it is of India-Pakistan relations. True, the near-term likelihood of war erupting in the region as a direct consequence of these disputes is slight; but that the regionâs water rivalries are already fraying tempers, deepening distrust, and, in myriad ways, acting as conflict multipliers cannot be denied. Added to this, of course, is that neighboring Chinaâs own extreme fresh water scarcity and its much-magnified interest in tapping into Tibetâs rich water resources hover threateningly over South Asian water supplies. Tibetâs water resources include the Brahmaputra river, already of unquestionably crucial importance to Bangladesh and India. With China now beginning to weigh in on the scales of South Asiaâs water security, the potential for serious confrontation over water resources is heightened still further. Increased basin-wide cooperation over these resources is one possibleâand, indeed, highly desirableâoutcome of these developments. One highly undesirableâbut perhaps no less possibleâoutcome, of course, is water war
Indirect Legacy Effects of an Extreme Climatic Event on a Marine Megafaunal Community
While extreme climatic events (ECEs) are predicted to become more frequent, reliably predicting their impacts on consumers remains challenging, particularly for large consumers in marine environments. Many studies that do evaluate ECE effects focus primarily on direct effects, though indirect effects can be equally or more important. Here, we investigate the indirect impacts of the 2011 âNingaloo Niñoâ marine heatwave ECE on a diverse megafaunal community in Shark Bay, Western Australia. We use an 18âyear communityâlevel data set before (1998â2010) and after (2012â2015) the heatwave to assess the effects of seagrass loss on the abundance of seven consumer groups: sharks, sea snakes (multiple species), Indoâpacific bottlenose dolphins (Tursiops aduncus), dugongs (Dugong dugon), green turtles (Chelonia mydas), loggerhead turtles (Caretta caretta), and Pied Cormorants (Phalacrocorax spp.). We then assess whether seagrass loss influences patterns of habitat use by the latter five groups, which are under risk of shark predation. Sharks catch rates were dominated by the generalist tiger shark (Galeocerdo cuvier) and changed little, resulting in constant apex predator density despite heavy seagrass degradation. Abundances of most other consumers declined markedly as food and refuge resources vanished, with the exception of generalist loggerhead turtles. Several consumer groups significantly modified their habitat use patterns in response to the dieâoff, but only bottlenose dolphins did so in a manner suggestive of a change in riskâtaking behavior. We show that ECEs can have strong indirect effects on megafauna populations and habitat use patterns in the marine environment, even when direct effects are minimal. Our results also show that indirect impacts are not uniform across taxa or trophic levels and suggest that generalist marine consumers are less susceptible to indirect effects of ECEs than specialists. Such nonâuniform changes in populations and habitat use patterns have implications for community dynamics, such as the relative strength of direct predation and predation risk. Attempts to predict ecological impacts of ECEs should recognize that direct and indirect effects often operate through different pathways and that taxa can be strongly impacted by one even if resilient to the other
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Forest habitat types on the Medicine Bow National Forest, southeastern Wyoming : preliminary report
A vegetation classification based on concepts and methods developed by Daubenmire was used to identify five habitat types and their related phases on the Medicine Bow National Forest: Abies lasiocarpa/Vaccinium scoparium, including the Pinus contorta/Vaccinium scoparium community; Abies lasiocarpa/Carex geyeri, including the Pinus contorta/Carex geyeri community; Populus tremuloides/Carex geyeri; Pinus ponderosa/Carex geyeri; and Pinus flexilis/Carex geyeri. A key to identify the habitat types and management implications associated with them are provided.Keywords: Vegetation classification, Abies lasiocarpa, Picea
engelmannii, Pinus contorta, Pinus ponderosa, Pinus flexilis,
Populus tremuloides
The epidemiology of pertussis in Germany: past and present
<p>Abstract</p> <p>Background</p> <p>Current and past pertussis epidemiology in the two parts of Germany is compared in the context of different histories of vaccination recommendations and coverage to better understand patterns of disease transmission.</p> <p>Methods</p> <p>Available regional pertussis surveillance and vaccination coverage data, supplemented by a literature search for published surveys as well as official national hospital and mortality statistics, were analyzed in the context of respective vaccination recommendations from 1964 onwards.</p> <p>Results</p> <p>Routine childhood pertussis vaccination was recommended in the German Democratic Republic (GDR) from 1964 and in former West German states (FWG) from 1969, but withdrawn from 1974â1991 in FWG. Pertussis incidence declined to <1 case/100.000 inhabitants in GDR prior to reunification in 1991, while in FWG, where pertussis was not notifiable after 1961, incidence was estimated at 160â180 cases/100.000 inhabitants in the 1970s-1980s. Despite recommendations for universal childhood immunization in 1991, vaccination coverage decreased in former East German States (FEG) and increased only slowly in FWG. After introduction of acellular pertussis vaccines in 1995, vaccination coverage increased markedly among younger children, but remains low in adolescents, especially in FWG, despite introduction of a booster vaccination for 9â17 year olds in 2000. Reported pertussis incidence increased in FEG to 39.3 cases/100.000 inhabitants in 2007, with the proportion of adults increasing from 20% in 1995 to 68% in 2007. From 2004â2007, incidence was highest among 5â14 year-old children, with a high proportion fully vaccinated according to official recommendations, which did not include a preschool booster until 2006. Hospital discharge statistics revealed a ~2-fold higher pertussis morbidity among infants in FWG than FEG.</p> <p>Conclusion</p> <p>The shift in pertussis morbidity to older age groups observed in FEG is similar to reports from other countries with longstanding vaccination programs and suggests that additional booster vaccination may be necessary beyond adolescence. The high proportion of fully vaccinated cases in older children in FEG suggests waning immunity 5â10 years after primary immunisation in infancy. The higher incidence of pertussis hospitalisations in infants suggests a stronger force of infection in FWG than FEG. Nationwide pertussis reporting is required for better evaluation of transmission patterns and vaccination policy in both parts of Germany.</p
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Towards a cohesive, holistic view of top predation: a definition, synthesis and perspective
Research on the ecology of top predators â upper trophic level consumers that are relatively free from predation once they reach adult size â has provided regular contributions to general ecology and is a rapidly expanding and increasingly experimental, multidisciplinary and technological endeavour. Yet, an exponentially expanding literature coupled with rapid disintegration into specialized, disconnected subfields for study (e.g. vertebrate predators versus invertebrate predators, community ecology versus biological control etc.) increasingly means that we are losing a coherent, integrated understating of the role and importance of these species in ecosystems. This process of canalization is likely to hinder sharing of scientific discovery and continued progress, especially as there is a growing need to understand the generality of the topâdown forcing, as demonstrated for some members of this group. Here, we propose ways to facilitate synthesis by promoting changes in mentality and awareness among specialists through increased debate and collaboration, conceptual reviews and a series of exemplary case studies. The strategy will rely on the collective contribution by all scientists in the field and will strive to consolidate and formalise top-order predation as a holistic, cohesive, cross-taxonomical field of research studying the ecology, evolution and behaviour of apex predators and their capability to exert topâdown forcing on lower trophic levels.SYNTHESIS:
The ongoing global loss of top predators and their recolonization of various regions are causing a rapid upsurge
of studies on these species and a consequent fragmentation of this field into disconnected, specialized subcompartments:
this will weaken efforts to produce synthetic generalisations of broader ecological interest. Here,
we show that top predation provides regular contributions to general ecology, is well grounded in theoretical
ecology and is a rapidly expanding and increasingly experimental, multidisciplinary and technological field of
research. The novelty of this forum lies in providing a concise synthesis of this area of ecology, in attempting
to formalise âtop predationâ as a specific, inter-connected area of investigation, and in proposing a marked
change of mentality by stressing the need for cross-taxonomic approaches enabling broader views of the role of
predators in ecosystems
Saving the worldâs terrestrial megafauna
From the late Pleistocene to the Holocene, and now the so called Anthropocene, humans have been driving an ongoing series of species declines and extinctions (Dirzo et al. 2014). Large-bodied mammals are typically at a higher risk of extinction than smaller ones (Cardillo et al. 2005). However, in some circumstances terrestrial megafauna populations have been able to recover some of their lost numbers due to strong conservation and political commitment, and human cultural changes (Chapron et al. 2014). Indeed many would be in considerably worse predicaments in the absence of conservation action (Hoffmann et al. 2015). Nevertheless, most mammalian megafauna face dramatic range contractions and population declines. In fact, 59% of the worldâs largest carnivores (â„ 15 kg, n = 27) and 60% of the worldâs largest herbivores (â„ 100 kg, n = 74) are classified as threatened with extinction on the International Union for the Conservation of Nature (IUCN) Red List (supplemental table S1 and S2). This situation is particularly dire in sub-Saharan Africa and Southeast Asia, home to the greatest diversity of extant megafauna (figure 1). Species at risk of extinction include some of the worldâs most iconic animalsâsuch as gorillas, rhinos, and big cats (figure 2 top row)âand, unfortunately, they are vanishing just as science is discovering their essential ecological roles (Estes et al. 2011). Here, our objectives are to raise awareness of how these megafauna are imperiled (species in supplemental table S1 and S2) and to stimulate broad interest in developing specific recommendations and concerted action to conserve them
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Status and Ecological Effects of the Worldâs Largest Carnivores
Large carnivores face serious threats and are experiencing massive declines in their populations and geographic ranges around the world. We highlight how these threats have affected the conservation status and ecological functioning of the 31 largest mammalian carnivores on Earth. Consistent with theory, empirical studies increasingly show that large carnivores have substantial effects on the structure and function of diverse ecosystems. Significant cascading trophic interactions, mediated by their prey or sympatric mesopredators, arise when some of these carnivores are extirpated from or repatriated to ecosystems. Unexpected effects of trophic cascades on various taxa and processes include changes to bird, mammal, invertebrate, and herpetofauna abundance or richness; subsidies to scavengers; altered disease dynamics; carbon sequestration; modified stream morphology; and crop damage. Promoting tolerance and coexistence with large carnivores is a crucial societal challenge that will ultimately determine the fate of Earthâs largest carnivores and all that depends upon them, including humans.This is the author's version of the work. It is posted here by permission of the American Association for the Advancement of Science for personal use, not for redistribution. The definitive version was published in Science, Vol. 343 (2014), doi:10.1126/science.1241484. The published article can be found at: http://www.sciencemag.org/
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