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Robert M. "Bob" May, Lord May of Oxford, O.M., who was the second recipient of the Ecological Society of America's Robert H. MacArthur Award, passed away at the age of 84 in Oxford, UK, on April 28, after a long illness. After a brief return to Australia, May was hired at Princeton to be a colleague of MacArthur and others; but sadly, he became in effect MacArthur's replacement after the latter's untimely death. Both Birch, who won the ESA's Eminent Ecologist Award in 1988, and the brilliant physicist Freeman Dyson, who was at the Princeton Institute for Advanced Study when May visited on a sabbatical in 1971, had suggested that Bob talk with MacArthur about whether he should change fields and become a theoretical ecologist. Bob continued to retain a Visiting Professorship at Princeton, where he would visit Princeton colleagues and friends and lecture on almost an annual basis until his declining health made that impossible; he received an honorary degree along with President Bill Clinton at Princeton's 250th anniversary in 1996. [Extracted from the article]

The article discusses research being done on the balance between conservation and national development. it references the study "Road as a Threat to the Serengeti Ecosystem," by R. Fyumagwa et al. in the 2013 issue of "Conservation Biology." Topics discussed include the impact of road construction on the ecosystem inside the Serengeti National Park in Tanzania, the alternative route for the road by which Tanzania could alleviate poverty, and the economic value of the three of possible routes.

Current unprecedented declines in biodiversity reduce the ability of ecological communities to provide many fundamental ecosystem services. Here we evaluate evidence that reduced biodiversity affects the transmission of infectious diseases of humans, other animals and plants. In principle, loss of biodiversity could either increase or decrease disease transmission. However, mounting evidence indicates that biodiversity loss frequently increases disease transmission. In contrast, areas of naturally high biodiversity may serve as a source pool for new pathogens. Overall, despite many remaining questions, current evidence indicates that preserving intact ecosystems and their endemic biodiversity should generally reduce the prevalence of infectious diseases. [ABSTRACT FROM AUTHOR]

Tree cover is a fundamental structural characteristic and driver of ecosystem processes in terrestrial ecosystems, and trees are a major global carbon (C) sink. Fire and herbivores have been hypothesized to play dominant roles in regulating trees in African savannas, but the evidence for this is conflicting. Moving up a trophic scale, the factors that regulate fire occurrence and herbivores, such as disease and predation, are poorly understood for any given ecosystem. We used a Bayesian statespace model to show that the wildebeest population irruption that followed disease (rinderpest) eradication in the Serengeti ecosystem of East Africa led to a widespread reduction in the extent of fire and an ongoing recovery of the tree population. This supports the hypothesis that disease has played a key role in the regulation of this ecosystem. We then link our state-space model with theoretical and empirical results quantifying the effects of grazing and fire on soil carbon to predict that this cascade may have led to important shifts in the size of pools of C stored in soil and biomass. Our results suggest that the dynamics of herbivores and fire are tightly coupled at landscape scales, that fire exerts clear top-down effects on tree density, and that disease outbreaks in dominant herbivores can lead to complex trophic cascades in savanna ecosystems. We propose that the long-term status of the Serengeti and other intensely grazed savannas as sources or sinks for C may be fundamentally linked to the control of disease outbreaks and poaching. [ABSTRACT FROM AUTHOR]

Evaluating changes in range size of land bird species using Millenium Ecosystem Assessment scenarios reveals that land conversion, as well as climate change, will lead to the decline of many species, particularly those in the tropics. [ABSTRACT FROM AUTHOR]

The provisioning of sustaining goods and services that we obtain from natural ecosystems is a strong economic justification for the conservation of biological diversity. Understanding the relationship between these goods and services and changes in the size, arrangement, and quality of natural habitats is a fundamental challenge of natural resource management. In this paper, we describe a new approach to assessing the implications of habitat loss for loss of ecosystem services by examining how the provision of different ecosystem services is dominated by species from different trophic levels. We then develop a mathematical model that illustrates how declines in habitat quality and quantity lead to sequential losses of trophic diversity. The model suggests that declines in the provisioning of services will initially be slow but will then accelerate as species from higher trophic levels are lost at faster rates. Comparison of these patterns with empirical examples of ecosystem collapse (and assembly) suggest similar patterns occur in natural systems impacted by anthropogenic change. In general, ecosystem goods and services provided by species in the upper trophic levels will be lost before those provided by species lower in the food chain. The decrease in terrestrial food chain length predicted by the model parallels that observed in the oceans following overexploitation. The large area requirements of higher trophic levels make them as susceptible to extinction as they are in marine systems where they are systematically exploited. Whereas the traditional species area curve suggests that 50% of species are driven extinct by an order-of-magnitude decline in habitat abundance, this magnitude of loss may represent the loss of an entire trophic level and all the ecosystem services performed by the species on this trophic level. [ABSTRACT FROM AUTHOR]

Historically, the role of parasites in ecosystem functioning has been considered trivial because a cursory examination reveals that their relative biomass is low compared with that of other trophic groups. However there is increasing evidence that parasite-mediated effects could be significant: they shape host population dynamics, alter interspecific competition, influence energy flow and appear to be important drivers of biodiversity. Indeed they influence a range of ecosystem functions and have a major effect on the structure of some food webs. Here, we consider the bottom-up and top-down processes of how parasitism influences ecosystem functioning and show that there is evidence that parasites are important for biodiversity and production; thus, we consider a healthy system to be one that is rich in parasite species. [Copyright &y& Elsevier]

This paper provides an overview of what the Millennium Ecosystem Assessment (MA) calls "indirect and direct drivers" of change in ecosystem services at a global level. The MA definition of a driver is any natural or human-induced factor that directly or indirectly causes a change in an ecosystem. A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely by altering one or more direct drivers. Global driving forces are categorized as demographic, economic, sociopolitical, cultural and religious, scientific and technological, and physical and biological. Drivers in all categories other than physical and biological are considered indirect. Important direct drivers include changes in climate, plant nutrient use, land conversion, and diseases and invasive species. This paper does not discuss natural drivers such as climate variability, extreme weather events, or volcanic eruptions. [ABSTRACT FROM AUTHOR]

Within the next 50 to 100 years, support and maintenance of an extended human family of 8 to 11 billion people will become difficult at best. The consumption rates already exceed the supply of many resources crucial to human health, and few places on Earth do not bear the stamp of human impacts. Thus, a research perspective that incorporates human activities as integral components of Earth's ecosystems is needed, as is a focus on a future in which Earth's life support systems are maintained while human needs are met. Ecological science has been important in improving human life, and research addressing the sustainability and resilience of socioecological systems has begun.