Author: postMigrator

Evolutionary biology and practical conservation: bridging a widening gap

GEORGINA M. MACE, ANDY PURVIS (2008)
Molecular Ecology, Volume 17 Issue 1 Page 9-19, January 2008
doi:10.1111/j.1365-294X.2007.03455.x

Full article online at :
<http://www.blackwell-synergy.com/doi/full/10.1111/j.1365-294X.2007.03455.x>

Correspondence: Georgina M. Mace, Fax: 01344
873173; E-mail: g.mace@imperial.ac.uk

Keywords: biodiversity goals, conservation planning, evolution, policy

“Habitat conversion continues in most parts of the world, especially in areas of high species richness, and novel threats, especially climate change, will pose new challenges.”

“Not all populations or species are equally likely to become extinct. Vulnerability to local extinction is commonly associated with low abundance, high habitat specificity, large body size and slow reproductive rates. In cases where both body size and life history have been studied, life history has been shown to be more important in carnivores (Cardillo et al. 2004; Purvis et al. 2000b) and, interestingly, in the extinction of large mammals in the late Quaternary (Johnson 2002). …. Top predators also appear to be especially threatened in mammals (Purvis et al. 2000a; Cardillo et al. 2004). ”

” Similarly, among the mammalian carnivores high threat rates are found in species that inhabit areas of high human population density (Cardillo et al. 2004). …. For example, large body size is often associated with present-day vulnerability, but is only patchily linked with extinction rates in the prehuman past (Purvis et al. 2003)”

“While the major drivers of biodiversity loss (overexploitation, habitat loss, introduced species, climate change and pollution) remain there is little likelihood that the trends will be slowed or reversed in the near future, and every likelihood that further losses will result, unless major changes in policy and practice are implemented (Millennium Ecosystem Assessment 2005a).”

“Developing species recovery plans

“This is the most obvious point at which evolutionary processes could and should be prioritized (Ashley et al. 2003). Opportunities for continued evolution and adaptive change can be encouraged by relatively simple mechanisms. For example, ensuring adequate genetic diversity by maintaining connectedness of related populations, starting with high levels of genetic diversity, avoiding inbreeding, and preserving the species across the range of habitats in which it is found, as well as at significant boundaries such as ecotones. These simple mechanisms will increase the adaptive nature of the landscape, and the potential for evolutionary change in response to it.

“One obstacle is the potential for over-emphasizing the differences between population subunits and attempting to conserve as separate units any population subunit for which evidence of reproductive isolation or genetic distinctiveness can be found. With the increasing precision and rigour of molecular genetic tools it is rare, given sufficient time and effort, for some genetic distinctiveness not to be found, albeit a result of recent genetic drift or random founder effects and having little consequence for adaptive distinctiveness. While the incorporation of molecular methods into the assessment of conservation units (such as ESUs; Moritz 1995) provided welcome rigour and clarity, uncritical application of these methods can be detrimental to the broader goal of preserving adaptive diversity.”

Full article online at :
<http://www.blackwell-synergy.com/doi/full/10.1111/j.1365-294X.2007.03455.x>

This article is cited by:

* THOMAS B. SMITH and LOUIS BERNATCHEZ.
(2008) Evolutionary change in human-altered environments. Molecular Ecology 17:1, 1-8

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News release
University of Florida
Monday, December 17, 2007.
http://news.ufl.edu/2007/12/17/golbal-warming/

Ancient global warming changed earth from ‘icehouse to greenhouse’

GAINESVILLE, Fla. – Earth literally turned over a new leaf 15 million years ago when an earlier version of global warming changed large parts of the planet from lush forests to open grasslands, a new study by scientists at the University of Florida and other institutions shows.

In a portent of today’s global warming, fossilized leaves tell the story of a carbon dioxide induced warm-up at the end of the Miocene age that melted much of the polar icecaps and led to the spread of animals that thrive in the wide open spaces, such as horses, camels and other grazers, said David Dilcher, a UF paleobotanist and one of the study’s authors.

“Our findings clearly demonstrate that past climate changes were tied to carbon dioxide fluctuations in the atmosphere, which influenced the major vegetation patterns occurring on earth and in turn affected the evolution of major animal groups,” Dilcher said.

The work by Dilcher, Wolfram Kurschner, a paleobotanist at Utrecht University in the Netherlands, and Zlatko Kvacek, a paleobotanist at Charles University in the Czech Republic, appears in a paper published this week in the online edition of the Proceedings of the National Academy of Sciences.

“The relevance for today is that the Antarctic ice sheets are reversing again,” said Dilcher, who works at the Florida Museum of Natural History. “As carbon dioxide and other gasses increase in the atmosphere, we’re emerging from a cooler or icehouse-type period into a greenhouse-type period with ice-free poles. The Earth is gradually going to undergo major changes just as we saw major changes in the upper Miocene Epoch.”

The Miocene Epoch is characterized by weather extremes, from the Earth plunging into its present “icehouse” state with glaciers at the north and south poles to periods of tropical temperatures.

While use of fossil fuels has been blamed for today’s global warming, the likely source of this ancient episode was carbon dioxide belched from widespread volcanic eruptions in the Columbia River Flood Basalt region of the United States and in Central Europe, Dilcher said.

The researchers were able to track the fluctuating levels of carbon dioxide in the atmosphere by taking fossilized leaves and measuring the number of stoma or small pores, through which carbon dioxide is taken in and oxygen released during photosynthesis. The more carbon dioxide in the atmosphere, the fewer stomata there are on the undersides of leaves.

Using three different species of leaves from the Charles University collection, with most of the specimens collected from the brown-coal basins in the Czech Republic, the researchers found a correlation between the number of stoma in the leaves and carbon dioxide levels in the air with climate patterns over time. The carbon dioxide fluctuations coincided with temperature changes recorded in the ocean record – as measured by isotope concentrations in the shells of marine organisms – which, in turn, corresponded with drastic changes in plant and animal life, Dilcher said.

“It was at the very end of the Miocene Age that modern vegetation emerges in the world, and we find that atmospheric carbon dioxide was the forcing factor,” he said.

Fluctuating levels of carbon dioxide combined with reduced available moisture, in the rain shadow of the rising Rocky Mountains, pressured the forest vegetation and photosynthesis of some plants to be altered. As a result, the closed forests of palm and bamboo trees that had dominated interior North America gave way first to savannas and open woodlands and later to grasslands, which also sprouted up across the ocean around the eastern Mediterranean, Dilcher said. These changes occurred gradually, over a few thousand to millions of years, he said.

The Great Plains began to form, leading to a diverse mix of large hoofed herbivores such as extinct species of horses, camels, rhinoceroses and elephants that fed on the lush grasses, he said.

“Preliminary data suggest that this pattern of elevated ungulate diversity is a global phenomenon, and therefore a global driving force such as climate change is the most likely explanation,” he said.

While carbon dioxide levels fluctuated between 370 and 600 parts per million during the Miocene Epoch, today’s levels are at about 375 parts per million, Dilcher said.

“We are in a period of accelerated climate change that is quite unlike anything that we have seen in the fossil record,” he said. “When carbon dioxide levels go up to 400 and then on to 500 parts per million, we will be at the same point that we were in the Miocene age when the poles were ice-free.”

© University of Florida, Gainesville, FL 32611; (352) 392-3261.
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Telegraph (UK)       December 17, 2006

Italy’s woodlands dying due to climate change
<http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/12/17/eaitaly117.xml>
By Michael Day in Milan

Italy’s woodlands are already dying as climate change starts to bite in southern Europe, experts warn.

A report represented to the Italian government said that eight out of 10 trees across Italy’s varied ecosystems were already suffering from the effects of rising temperatures and diminishing rainfall.

Professor Carlo Blasi of the Inter-university Centre for Bio-diversity at Rome’s La Sapienza University said the research showed that a third of the country’s woodland was seriously threatened, and that 60 per cent was likely to suffer permanent damage.

The warning echoes fears that the Mediterranean, and Italy in particular, is proving highly vulnerable to climate change.

Climatologist Dr Filippo Giorgi of the UN’s Intergovernmental Panel on Climate Change, told a major environment conference in Rome in September that the Mediterranean was warming up faster than the rest of the world.

“It’s a climate change hot spot, one of the areas where we actually see the change happening”.

Dr Giorgi said that in the next decades temperature rises in Europe during the summer months could be 40-50 per cent higher than elsewhere.

Of the six major droughts to occur in Italy in the last 60 years, four have occurred since 1990. The average temperature has increased by 0.4ºC in the north in 20 years and by 0.7ºC in the south. Earlier report have suggest that 10m hectares were “at risk of desertification”.

Prof Blasi noted that many of Italy’s tree species were ill-equipped to survive hotter, drier conditions.

“Despite its large Mediterranean coastline, Italy has a relatively low proportion – just 40 per cent – of the shrubby Mediterranean trees that are best adapted to resist the heat waves that are on their way,” he told La Repubblica newspaper.

“The other 60 per cent are particularly likely to suffer from increasingly hot and arid conditions.”

Most surprising, said Prof Blasi, was how widespread the threat was across Italy.

The regions of Tuscany, Umbria, Abruzzo, Puglia and also the islands of Sicily and Sardinia were being hard hit by rising temperatures, with several species of oak and beech tree in particular under threat.

Lack of rainfall was proving the biggest threat to woodland in the Alpine north of the country.

In Sicily and Sardinia, cork trees, the evergreen Holm-oak and even some compact Mediterranean tree species were threatened by the increasingly arid conditions.

In response to the report Environment minister Alfonso Pecoraro Scanio said: “Fewer woodlands mean, among other things, reduced capacity to absorb carbon dioxide released into the atmosphere.”

He said that to “break this vicious ciricle” his government had set aside £110m to tackle degradation of forests and woodlands.

Like other Southern European countries, Italy has also lost considerable areas of woodland to forest fires, which although fanned by hot winds, are often started deliberately.

Pecoraro Scanio lamented the failure of Italy’s fractious parliament to agree to fund a new body to investigate the cause of such blazes and “defend itself from the criminals that set fire to the forests”.

He predicted more woodland and forest would perish from such fires in the summers to come.

It is not not only Italy’s forests that are causing enviromentalists concern, however.

Scientists at Italy’s Agency for New technology, Energy and the Environment (ENEA), say that failing cold currents and rising water temperatures are exacerbating periodic flooding – and this is causing massive erosion along Italy’s Adriatic coast.

As a result they have drawn up a plan in which hundreds of miles of new sand dunes would be created to save it the country’s most endangered coastline and its wildlife from rising sea levels.

Dr Edi Valpreda, who led the project, told Telegraph Earth that it was currently being considered by the environment ministry.
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