Archive for May, 2005

The formation of creative teams

Published by Line Gordon on May 28, 2005 in General and Ideas. 0 Comments

In a recent paper published in Science Guimerà and colleagues use network theory to investigate what makes teams sparklingly creative as compared to those less inventive. The authors use large datasets on producers of Broadway musicals and authors of scientific papers in Economics, Ecology, Social Psychology and Astronomy to document the character of successful teams. Factors that seem of importance include the fraction of veteran members of a team, as well as the extent to which veterans involve their former collaborators.

From Barabàsis analysis of the authors results:

To comprehend the structure of the collaboration map, we must understand how people form friendships and alliances. Given that in the professional world friendships are just as crucial as hard-nosed professional interests, modeling the evolution of creative teams may appear to be impossible. Guimeraà’s results indicate otherwise: They show that a simple model successfully captures many qualitative features of the network underlying the creative enterprise. In their study, they distinguish between veterans, who have participated in collaborations before, and rookies, who are about to see their names appear in print for the first time. Two parameters are key: the fraction of veteran members in a new team, and the degree to which veterans involve their former collaborators. If choosing experienced veterans is not a priority, the authors find that the network will be broken up into many small teams with little overlap between them. As the likelihood of relying on veterans increases, thanks to the extra links to earlier collaborators, the teams coalesce through a phase transition such that all players become part of a single cluster.

…

The results of the Guimerà et al. study indicate that expertise does matter: Teams publishing in highimpact journals have a high fraction of incumbents. But diversity matters too: Teams with many former collaborative links offer inferior performance. Thus, the recipe for success seems relatively simple: When forming a “dream team” make an effort to include the most experienced people, whether or not you have worked with them before. But diversity matters too: Teams with many former collaborative links offer inferior performance. Thus, the recipe for success seems relatively simple: When forming a “dream team” make an effort to include the most experienced people, whether or not you have worked with them before.

Nature uses fiction to communicate global risks of Avian flu

Published by Line Gordon on May 26, 2005 in Big Back Loop, General and Scenarios. 0 Comments

The 1918 flu pandemic killed 50 million people across the globe. This weeks Nature is devoted to the potential of an avian flu pandemic and contains both news and scientific reports on the subject. To highlight and communicate the risks involved story telling is used in the form of a future weblog, written by a made up freelance journalist.

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MA Biodiversity Synthesis released

Published by Garry Peterson on May 23, 2005 in Big Back Loop, Ideas and Millennium Ecosystem Assessment. 3 Comments

Ecosystems and Human Well-being: the Biodiversity Synthesis Report, the first cross-cutting synthesis report from the Millennium Ecosystem Assessment (MA) has been released at an event at McGill University. The report can be downloaded from the MA web site for free (its 13.4Mb).

Key findings of the study are:

+ Biodiversity benefits people through more than just its contribution to material welfare and livelihoods. Biodiversity contributes to security, resiliency, social relations, health, and freedom of choices and actions.

+ Changes in biodiversity due to human activities were more rapid in the past 50 years than at any time in human history, and the drivers of change that cause biodiversity loss and lead to changes in ecosystem services are either steady, show no evidence of declining over time, or are increasing in intensity. Under the four plausible future scenarios developed by the MA, these rates of change in biodiversity are projected to continue, or to accelerate.

+ Many people have benefited over the last century from the conversion of natural ecosystems to human-dominated ecosystems and from the exploitation of biodiversity. At the same time, however, these gains have been achieved at growing costs in the form of losses in biodiversity, degradation of many ecosystem services, and the exacerbation of poverty for some groups of people.

+ The most important direct drivers of biodiversity loss and ecosystem service changes are habitat change (such as land use changes, physical modification of rivers or water withdrawal from rivers, loss of coral reefs, and damage to sea floors due to trawling), climate change, invasive alien species, overexploitation, and pollution.

+ Improved valuation techniques and information on ecosystem services demonstrates that although many individuals benefit from biodiversity loss and ecosystem change, the costs borne by society of such changes are often higher. Even in instances where knowledge of benefits and costs is incomplete, the use of the precautionary approach may be warranted when the costs associated with ecosystem changes may be high or the changes irreversible.

+ To achieve greater progress toward biodiversity conservation to improve human well-being and reduce poverty, it will be necessary to strengthen response options that are designed with the conservation and sustainable use of biodiversity and ecosystem services as the primary goal. These responses will not be sufficient, however, unless the indirect and direct drivers of change are addressed and the enabling conditions for implementation of the full suite of responses are established.

+ An unprecedented effort would be needed to achieve by 2010 a significant reduction in the rate of biodiversity loss at all levels.

+ Short-term goals and targets are not sufficient for the conservation and sustainable use of biodiversity and ecosystems. Given the characteristic response times for political, socioeconomic, and ecological systems, longer-term goals and targets (such as for 2050) are needed to guide policy and actions.

+ Improved capability to predict the consequences of changes in drivers for biodiversity, ecosystem functioning, and ecosystem services, together with improved measures of biodiversity, would aid decision-making at all levels.

+ Science can help ensure that decisions are made with the best available information, but ultimately the future of biodiversity will be determined by society.

Biological Invasions Riskier than Thought

Published by Garry Peterson on May 11, 2005 in Ideas and Reorganization. 0 Comments

A new paper Invasion success of vertebrates in Europe and North America by Jonathan Jeschke and David Strayer from IES was published online in PNAS April 222.

Their paper examined patterns in to the introduction, establishment and spread of freshwater fish, mammals, and birds between Europe or North America.

Their paper produces a number of interesting results. First it suggests that risks from invasive species are much higher than previously thought. The 10:10 rule of thumb proposes that in the steps of establishment, spread only 1:100 introduced species should spread. This paper suggests it is 25X greater at 1/4.

This result is supported by their examination of other patterns shown below.

Graph from Paper

Figure 2. Proportions of introduced animals that establish themselves (establishment success) and of established animals that spread or are pests (spread success). The tens rule predicts a 10% success for either step (vertical dotted line). Planarians, alien terrestrial planarians established in the U.K.; insects, biocontrol insects, symbols denote different diets and propagule pressures; island mammals, mammals introduced to Ireland and Newfoundland ; Australian mammals; island birds, symbols denote different islands; continental birds, birds introduced to continental USA and Australia; world parrots, worldwide parrot introductions; E, NA vertebrates, European North American vertebrates according to Table 1 (this study); British animals, symbols denote different taxa; Austrian animals, symbols denote different taxa; German animals, symbols denote different native continents.

They also show that species movement between Canada and the USA and Europe is roughly equal, rather than it being mostly a Europe->N. America pattern.

Pleistocene Park: using grazing to produce a regime shift

Published by Garry Peterson on May 10, 2005 in Ecological Management, Ideas, Regime Shifts and Tools. 0 Comments

Sergey A. Zimov has an article in the 6 May 2005 Science about his efforts to create a Pleistocene Park where recreated Pleistocene grazing will flip from a moss dominated system to grassland. Its a great example of a large scale attempt to flip a system from one alternative state to another.

Zimov writes:

This view means that the present Holocene climate of northern Siberia, particularly near the present tree line, is likely just now to be optimal for the mammoth ecosystem. If we accept the argument that the pasture landscapes were destroyed because herbivore populations were decimated by human hunting, then it stands to reason that those landscapes can be reconstituted by the judicious return of appropriate herbivore communities.

In northern Siberia, mainly in the Republic of Yakutia, plains that once were covered by tens of meters of mammoth steppe soils now occupy a million square kilometers. The climate of the territory is near optimal for northern grassland ecosystems. Thus, in principle, the ancient mammoth ecosystem could be restored there.

In Yakutia, we are trying to do just that. The government has adopted a program to restore the republic’s former biodiversity. One thrust of this effort has been through the nonprofit organization of Pleistocene Park–of which I am a founding member–on 160 km2 of Kolyma lowland. One-third of the territory is meadow, one-third is forest, and one-third is willow shrubland. Today, many of the animals of the mammoth ecosystem and grasses remain in northern Yakutia.

Reindeer, moose, Yakutian horses, recently reintroduced musk oxen, hares, marmots, and ground squirrels forage for vegetation, and predators, including wolves, bears, lynxes, wolverines, foxes, polar foxes, and sables, prey on the herbivores. However, strong hunting pressure has kept the overall number of animals low. Therefore, their influence on vegetation is small. The first step for Pleistocene Park, which we are just now initiating, is to gather the surviving megafauna of the mammoth ecosystem (initially without predators) within the part of the parkland that is rich in grassland. The second step will be to increase the herbivore density sufficiently to influence the vegetation and soil. As animal densities increase, the fenced boundary will be expanded.

The most important phase of the program will be the reintroduction of bison from Canada and subsequently, when the herbivores are sufficiently abundant, the acclimatization of Siberian tigers. In many regions of the Amur River basin, where this formidable predator survives, January temperature is as low as -25º to -30ºC. The tigers’ survival there is limited more by poaching and herbivore density than by climate. Scientifically, Pleistocene Park is important because it directly tests the role of large herbivores in creating and maintaining grassland ecosystems, something that can only be surmised but not proven from the paleorecord.

Science 282, 31-34 (1998)] also had a news story by R. Stone about the start of Zimov’s ambitious Pleistocene Park project: A Bold Plan to Re-Create a Long-Lost Siberian Ecosystem

Positive Steps for Resilient Ecosystem Services

Published by Steve Carpenter on May 2, 2005 in Big Back Loop, Ideas, Millennium Ecosystem Assessment and Scenarios. 4 Comments

Although much of the mainstream press attention to the Millennium Ecosystem Assessment (see State of the World’s Ecosystems posted 31 March 2005) has emphasized the losses of ecosystem services and the adverse trends, a substantial fraction of the MA technical reports is devoted to positive, feasible steps that can be taken to improve ecosystem services in the future. All of these proactive steps are grounded in policies that are presently in place somewhere in the world today. A few examples:

• Increase the use of economic instruments and market-based approaches, e.g. assignments of property rights for ecosystem services, user fees for externalities, payment for ecosystem services, and mechanisms to express consumer preferences through markets (such as certification schemes)

• Explicitly include ecosystem services in poverty-reduction strategies

• Connect environmental management across ministries and sectors, instead of isolating it in a single ministry

• Create co-management systems to maintain reserves as part of regional mosaics

• Include local and indigenous knowledge, as well as technical knowledge, in decision-making

• Expand information available to individuals about how ecosystems affect them, and how their actions affect ecosystems

• Expand environment-friendly technology, especially in the areas of agriculture (water, nutrient and land use), urban design, and energy efficiency

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