Category Archives: General

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Nitrogen deposition making lakes more regulated by phosphorus

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Nitrogen deposition is increased the extent to which lake algal populations are regulated by phosphorus, shifting lake food webs.  Because, the patterns of human amplification of nitrogen and phosphorus trasport are different this should drive different patterns in lakes in different regions.

James Elser and other write in Science Shifts in Lake N:P Stoichiometry and Nutrient Limitation Driven by Atmospheric Nitrogen Deposition (2009 326 (5954):835).  From the abstract:

Human activities have more than doubled the amount of nitrogen (N) circulating in the biosphere. One major pathway of this anthropogenic N input into ecosystems has been increased regional deposition from the atmosphere. Here we show that atmospheric N deposition increased the stoichiometric ratio of N and phosphorus (P) in lakes in Norway, Sweden, and Colorado, United States, and, as a result, patterns of ecological nutrient limitation were shifted. Under low N deposition, phytoplankton growth is generally N-limited; however, in high–N deposition lakes, phytoplankton growth is consistently P-limited.

They conclude:

Our findings show that, despite the potential of watershed vegetation uptake and sediment denitrification to buffer lakes against elevated N loading, increased inputs of anthropogenic N have accumulated in receiving waters. As a result, shifts in lake N:P stoichiometry have altered ecological nutrient limitation of phytoplankton growth. Phytoplankton in lakes that are less influenced by anthropogenic inputs experience relatively balanced or N-deficient nutrient supplies, but enhanced N inputs from the atmosphere during the past several decades of human industrialization and population expansion appear to have produced regional phytoplankton P limitation.

Producer diversity is likely to be low when resource supply ratios are skewed in favor of one particular nutrient relative to others (11, 18). Thus, increased N loading from the atmosphere may reduce lake phytoplankton biodiversity, similar to anticipated effects of N deposition on plant diversity in terrestrial ecosystems (19, 20), by possibly favoring those relatively few species that are best able to compete for the limiting P.

… Thus, sustained N deposition that generates stoichiometric imbalance between P-limited, low-P phytoplankton and their P-rich zooplankton consumers (12) may result in reduced production of higher trophic levels, such as fish. Projected increases in global atmospheric N transport during the coming decades (24) are likely to substantially influence the ecology of lake food webs, even in lakes far from direct human disturbance.

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Huarango and coastal Peruvian resilience

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image-4-desertificationFollowing up on a previous post about the resilience of the Nasca, the New York Times reports on the continued destruction of the huarango in the present day.

The huarango, a giant relative of the mesquite tree of the American Southwest, survived the rise and fall of Pre-Hispanic civilizations, and plunder by Spanish conquistadors, whose chroniclers were astounded by the abundance of huarango forests and the strange Andean camelids, like guanacos and llamas, that flourished there.

Today, though, Peruvians pose what might be a final challenge to the fragile ecosystem supported by the huarango near the southwestern coast of Peru. Villagers are cutting down the remnants of these once vast forests. They covet the tree as a source of charcoal and firewood.

The depletion of the huarango is raising alarm among ecologists and fostering a nascent effort to save it.

… many Peruvians view the huarango as prime wood for charcoal to cook a signature chicken dish called “pollo broaster.” The long-burning huarango, a hardwood rivaling teak, outlasts other forms of charcoal. Villagers react to a prohibition by regional authorities on cutting down huarango with a shrug.

…That the huarango survives at all to be harvested may be something of a miracle. Following centuries of systematic deforestation, only about 1 percent of the original huarango woodlands that once existed in the Peruvian desert remain, according to archaeologists and ecologists.Few trees are as well suited to the hyperarid ecosystem of the Atacama-Sechura Desert, nestled between the Andes and the Pacific. The huarango captures moisture coming from the west as sea mist. Its roots are among the longest of any tree, extending more than 150 feet to tap subterranean water channels.

…

“Peru needs a massive rethink about its development trajectory,” said Alex Chepstow-Lusty, a paleoecologist with the French Institute of Andean Studies who worked on the Nazca study with Mr. Beresford-Jones, the Cambridge University archaeologist, analyzing pollen that showed the transformation of Nazca lands from rich in huarango to fields of maize and cotton to the virtually lifeless desert that exists today.

“With Peru’s glaciers predicted to disappear by 2050, the Andes need trees to capture the moisture coming from Amazonia, which is also the source of water going down to the coast,” said Mr. Chepstow-Lusty in an interview from Cuzco, in Peru’s highlands. “Hence a major program of reforestation is required, both in the Andes and on the coast.”

Nothing on this scale is happening around Ica. Instead, the growth that one sees in poor villages are of shantytowns called pueblos jóvenes, where residents eke out a living as farmhands or in mining camps.

Outside one village, Santa Luisa, the buzz of a chainsaw interrupted the silence of the desert next to an oven preparing charcoal.

The chainsaw’s owner, a woodcutter from the highlands named Rolando Dávila, 48, swore that he no longer cut down huarango but focused instead on the espino, another hardy tree known as acacia macarantha. “But we all know huarango is the prize of the desert,” he said. “For many of us, the wood of the huarango is the only way to survive.”

The UK’s Kew Gardens has a few pages about their huarango restoration project.  The BBC also has an article about this project.

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Income, fertility and the world’s demographic trajectory

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Avg. Income vs. Fertility from Gapminder

data from Gapminder

The Economists looks at recent declines in fertility discusses current projections of world population, and how changes in a country’s demographic structure shape its economic development (but it doesn’t mention the role of urbanization).  In Fertility and living standards it writes:

Sometime in the next few years (if it hasn’t happened already) the world will reach a milestone: half of humanity will be having only enough children to replace itself. That is, the fertility rate of half the world will be 2.1 or below. This is the “replacement level of fertility”, the magic number that causes a country’s population to slow down and eventually to stabilise. According to the United Nations population division, 2.9 billion people out of a total of 6.5 billion were living in countries at or below this point in 2000-05. The number will rise to 3.4 billion out of 7 billion in the early 2010s and to over 50% in the middle of the next decade. The countries include not only Russia and Japan but Brazil, Indonesia, China and even south India.

The move to replacement-level fertility is one of the most dramatic social changes in history. It manifested itself in the violent demonstrations by students against their clerical rulers in Iran this year. It almost certainly contributed to the rising numbers of middle-class voters who backed the incumbent governments of Indonesia and India. It shows up in rural Malaysia in richer, emptier villages surrounded by mechanised farms. And everywhere, it is changing traditional family life by enabling women to work and children to be educated. At a time when Malthusian alarms are ringing because of environmental pressures, falling fertility may even provide a measure of reassurance about global population trends. …

Higher standards of living, then, reduce fertility. And lower fertility improves living standards. This is what China’s government says. It is also the view that has emerged from demographic research over the past 20 years.  In the 1980s, population was regarded as relatively unimportant to economic performance. American delegates told a UN conference in 1984 that “population growth is, in and of itself, neither good nor bad; it is a neutral phenomenon.” Recent research suggests otherwise.

Cutting the fertility rate from six to two can help an economy in several ways. First, as fertility falls it changes the structure of the population, increasing the size of the workforce relative to the numbers of children and old people. When fertility is high and a country is young (median age below 20), there are huge numbers of children and the overall dependency ratio is high. When a country is ageing (median age above 40), it again has a high dependency ratio, this time because of old people.

But the switch from one to the other produces a Goldilocks generation. Because fertility is falling, there are relatively few children. Because of high mortality earlier, there are relatively few grandparents. Instead, countries have a bulge of working-age adults. This happened to Europe after the baby boom of 1945-65 and produced les trente glorieuses (30 years of growth). It is happening now in Asia and Latin America. East Asia has done better than Latin America, showing that lower fertility alone does not determine economic success. Eventually developing countries will face the same problems of ageing as Europe and Japan do. But for the moment, Asians and Latinos are enjoying fertility that is neither too hot, nor too cold. According to David Bloom of the Harvard School of Public Health, the “demographic dividend” (his term) accounted for a third of East Asian growth in 1965-90.

Slowing fertility has other benefits. By making it easier for women to work, it boosts the size of the labour force. Because there are fewer dependent children and old people, households have more money left for savings, which can be ploughed into investment. Chinese household savings (obviously influenced by many things, not just demography) reached almost 25% of GDP in 2008, helping to finance investment of an unprecedented 40% of GDP. This in turn accounted for practically all the increase in Chinese GDP in the first half of this year.

Lastly, low fertility makes possible a more rapid accumulation of capital per head. To see how, think about what happens to a farm as it is handed down the generations in a country without primogeniture. The more children there are, the more the farm is divided. Eventually, these patches become so tiny they cease to be efficient. …

This link between growth and fertility raises awkward questions. In the 1980s the link was downplayed in reaction to Malthusian alarms of the 1970s, when it was fashionable to argue that population growth had to be reined in because oil and natural resources were running short. So if population does matter after all, does that mean the Malthusians were right?

Not entirely. Neo-Malthusians think the world has too many people. But for most countries, the population questions that matter most are either: do we have enough people to support an ageing society? Or: how can we take advantage of having just the right number for economic growth? It is fair to say that these perceptions are not mutually exclusive. The world might indeed have the right numbers to boost growth and still have too many for the environment. The right response to that, though, would be to curb pollution and try to alter the pattern of growth to make it less resource-intensive, rather than to control population directly.

The reason is that widening replacement-level fertility means population growth is slowing down anyway. A further reduction of fertility would be possible if family planning were spread to the parts of the world which do not yet have it (notably Africa). But that would only reduce the growth in the world’s numbers from 9.2 billion in 2050 to, say, 8.5 billion. To go further would probably require draconian measures, such as sterilisation or one-child policies.

The bad news is that the girls who will give birth to the coming, larger generations have already been born. The good news is that they will want far fewer children than their mothers or grandmothers did.

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Why You Don’t Need an iPhone

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Old School Cell PhoneWired Science reported on a project  a while ago, based on innovative ecological crowd-sourcing in New York. The idea was quite simple. “Participants in the NYC Cricket Crawl will go out between dusk and midnight to record cricket calls for one minute, and then immediately send their results and location to the scientists by cellphone. The researchers are hoping to find evidence that the Common True Katydid, once plentiful in New York City but now rare, is still thriving in some regions of the city.” Quite innovative approach if you ask me, and the results are now up on their website.

But actually, many of the most innovative uses of information and communication technologies does not at all require fancy (and expensive) mobile technologies such as sound-recording iPhones. The Economist‘s September issue features the role of simple cell-phones in emerging markets. The most interesting examples are from Kerala (India) and Niger. In the first case, the spread of cellphones seems to have increased fishermen’s profit by 8%. The reason was that fishermen ”could call several markets while still at sea before deciding where to sell”. In Niger, increased mobile-phone coverage seems to have reduced price variation for grain, between local markets. As the Economist reports ”during a spike in food prices in 2005 grain was 4,5 % cheaper in markets with mobile coverage”. You can find a beautiful documentary of the societal impacts of increased use of mobile phones in Africa here.

A range of additional example of smart uses of quite simple communication technologies, such as SMS-messages and e-mail-lists – can be found in the health community. The moderated e-mail list ProMED has become a fundamental tool for rapid dissemination of information during health contingencies. Bangladesh as an additional example, is conducting active Highly Pathogenic Avian Influenza surveillance through an Short Message Service (SMS) gateway to collect data and report on disease and death in poultry. Since October 2008, 21 HPAI outbreaks out of a total of 35 have been detected through this active surveillance programme.

Simple technologies, big impacts. Even in an era of rapid information technological change, less is more.

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Three Climate Change Lecturer Positions at Tyndall Centre

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Neil Adger writes to announce three exciting research positions at UEA.

Three Lecturer Posts Ref: ATR842 (£37,651 to £43,622 per annum)

These new academic staff appointments at UEA have been created as a result of substantial new investments in the Tyndall Centre for Climate Change Research. The posts offer excellent opportunities for continuing, or developing, internationally outstanding research careers UEA is the Headquarters of the Tyndall Centre which includes the universities of Manchester, Southampton, Oxford, Newcastle, Sussex and Cambridge. At UEA, the Tyndall Centre’s interdisciplinary activities span the Faculty of Science and the Faculty of Social Sciences. These new positions will be based alongside existing Tyndall colleagues within the School of Environmental Sciences.

You must have a PhD (or equivalent) in an appropriate discipline in physical, natural, or social science, ideally with research interests in one or more of: land use and climate change; food security and climate change; mitigation, adaptation and behavioural change; energy and climate security; climate change and prosperity, and you must also be able to satisfy all other essential elements of the person specification. Applications from candidates with research interests in other climate-related areas will also be considered.

Closing date: 12 noon on 30 November 2009.

Further particulars and an application form are available on the UEA website www.uea.ac.uk/hr/jobs/ or Tel. + 44 (0)1603 593493. Ref: ATR842 (£37,651 to £43,622 per annum)

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How the Nazca lost their resilience?

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Remains of a Nasca canal cross a desertified landscape in the lower Ica Valley, Peru.

Remains of a Nazca canal cross a desertified landscape in the lower Ica Valley, Peru.

A paper by David Beresford-Jones and others (Latin American Antiquity 20, 303–33) that argues that deforestation, particularly of the deep rooted huarango, caused the Nazca civilization of Peru to loose their resilience to El Niño floods.  On the BBC David Beresford-Jones says:

The huarango tree (Prosopis pallida) is a unique tree with many qualities and played a vital role in the habitat, protecting the fragile desert ecosystem, the scientists say.

“It is the ecological keystone species in the desert zone enhancing soil fertility and moisture and underpinning the floodplain with one of the deepest root systems of any tree known,” Dr Beresford-Jones says.”

Nature News reports Native American culture sowed seeds of its own collapse:

Ice-core records suggested that severe storms — a mega El Niño — hit the Peruvian Andes around the time the Nazca’s fall began, but this had not been corroborated in the coastal valleys where the Nazca once lived. Beresford-Jones and his colleagues, focusing on the lower Ica valley, solidified this evidence when they discovered a flood layer that sat directly on top of a Nazca rubbish dump. The authors then recreated the flood using a computer simulation, demonstrating that a flood that left such a layer could have caused the damages to the Nazca canal system known to have occurred around 500 AD.

“But that’s not the end of the story,” says Beresford-Jones. “The landscape was only exposed to the effect of the El Niño because of what the Nazca were doing to their river valleys.”

Preserved tree trunks are scattered across the now-deserted lower Ica valley, about 200 km south of Lima, indicating a significant landscape change. To investigate this further, team member Alex Chepstow-Lusty of the French Institute of Andean Studies in Lima analyzed the pollen that had been blown to the edges of the basin by strong winds. For much of the older portion of the record, the pollen came from riparian trees, like huarango, which once created woodland oases that lined the rivers in the otherwise desert landscape.

But as Chepstow-Lusty moved forward in time through the pollen record, he found a gradual decrease in huarango pollen and a concomitant increase in pollen from agricultural sources, like cotton and maize, indicating that the Nazca were cutting down woodland to make room for farms. The records show that agricultural plants dramatically disappeared and were replaced by weeds; eventually the weeds died and the land became the lifeless desert it is today.

Beresford-Jones says that when the Nazca cut down the trees they destroyed the root system that had been anchoring the landscape.

“When the El Niño came it cut into the floodplain because it was no longer supported by woodland. That caused erosion and made the irrigation system useless,” he explains. “Storms like this should have just replenished the water table and wouldn’t have hurt them, but [the Nazca] exposed their own land.”

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Lessons from Diversitas

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The second Diversitas Open Science Conference was recently held in Capetown South Africa.  Eminent South African ecologist from Harry Biggs, writes What I learnt from the Diversitas Conference:

• Governance issues (esp. science-policy and science-management links) have become far more respectable in such fora, now filling much programme time. For instance, Anantha Duraiappah from Kenya gave a keynote entitled “Managing ecosystem services, institutions, property rights and scales”.

• Gretchen Daily (of ecosystem services and other fame) spoke of mainstreaming conservation “beyond parks, beyond charity, and beyond biodiversity”; while Pavan Sukhdev (a dynamic banker who has thrown his weight fully behind the Diversitas cause) spoke of getting beyond the point where biodiversity is now, merely a “luxury for the rich and a necessity for the poor”. He referred to the increasing use of the concept “ecological infrastructure” as conceptually similar to, say, constructed infrastructure in the traditional sense, and the imperative to invest in maintaining or rehabilitating this.

Daily and others are working on the following useful representation of the different processes we have to make work together if we are to succeed. The right-hand part was referred to by others as “the (traditional) science part” and the left-hand part as the part to which we have mostly given too little attention, in attempting to achieve our overall goals:

Much of the meeting was understandably about the difficult field of biodiversity targets. Daily suggested three types of targets:
BLUE – absolute ecosystem tipping points e.g. rates of climate change too fast
GREEN – societal choices about the desired state e.g. no more bird extinctions
RED – situations we must avoid e.g. imminent coral reef collapse (in my view some overlap with BLUE)

• Sukhdev and many others spoke about TEEB (The economics of ecosystem services and biodiversity), which, although young and developing, promises to make major impacts in our field. See www.teebweb.org.

Sukhdev pointed to sensible ways to deal complexity, feeling scientists often impeded progress because of what he called the “Popperian trap” of demanding ridiculous levels of proof sometimes even when it was absurd to do so, and when Rome was clearly burning. The ideas in the Precautionary Principle will have to be used, but in a more complexity-friendly way.

In my opinion we will as a community have to reconcile these needs, and not only use Mode 1 Science. Importantly, he reflected the invariable TEEB finding that returns on investment for just about all ecosystem services make for very profitable business, suggesting that one day soon these may really take off. My conclusion – perhaps we are poised for major changes in thinking. In additional, many speakers referred to “bundles” of related services as more realistic than looking at one service e.g. carbon sequestration, in isolation – in the same way that multi-species models or interventions often radically change outcomes when compared to single-species ones.

via Agricultural Biodiversity Weblog

General, Reorganization

Resilience as an operating system for sustainability in the anthropocene

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Chris Turner, author of Geography of Hope: A Tour of the World We Need, writing in the Walrus about the Anthropocene and the coral reef crisis in his long article Age of Breathing Underwater:

I first heard tell of “resilience” — not as a simple descriptive term but as the cornerstone of an entire ecological philosophy — just a couple of days before I met Charlie Veron on the pages of Melbourne’s most respected newspaper. I was onstage for the opening session of the Alfred Deakin Innovation Lectures in an auditorium at the University of Ballarat at the time. The evening had begun with a literal lament — a grieving folk song performed by an aboriginal musician. I’d then presented a slide show of what I considered to be the rough contours of an Anthropocene map of hope, after which a gentleman I’d just met, a research fellow at Australia’s prestigious Commonwealth Scientific and Industrial Research Organisation named Brian Walker, placed my work in the broader context of resilience theory.

I had to follow Veron all the way to the edge of the abyss his research had uncovered before I could come back around to resilience. The concept, it turns out, emerged from the research of a Canadian-born academic named Buzz Holling at the University of Florida, and has since been expanded by a global research network called the Resilience Alliance. “Ecosystem resilience” — this in the Resilience Alliance website’s definition — “is the capacity of an ecosystem to tolerate disturbance without collapsing into a qualitatively different state that is controlled by a different set of processes. A resilient ecosystem can withstand shocks and rebuild itself when necessary.” It’s a concept I encountered repeatedly in my conversations with reef researchers.

…This points to the broader implications of the resilience concept — the stuff Brian Walker likes to talk about. He and his colleagues in the Resilience Alliance often refer to their field of study as “social-ecological resilience,” suggesting that people are as essential to the process as reefs or any other ecosystem, and that real resilience is created in the complex, unpredictable interplay between systems. “With resilience,” Walker told me, “not only do we acknowledge uncertainty, but we kind of embrace uncertainty. And we try to say that the minute you get too certain, as if you know what the answer is, you’re likely to come unstuck. You need slack in the system. You need to have the messiness that enables self-organization in the system in ways that are not predictable. The best goal is to try to build a general resilience. Things like having strong connectivity, but also some modularity in the system so it’s not all highly connected everywhere. And lots of diversity.”

Resilience, then, embraces change as the natural state of being on earth. It values adaptation over stasis, diffuse systems over centralized ones, loosely interconnected webs over strict hierarchies. If the Anthropocene is the ecological base condition of twenty-first-century life and sustainability is the goal, or bottom line, of a human society within that chaotic ecology, then resilience might be best understood as the operating system Paul Hawken was on about — one with an architecture that encourages sustainability in this rapidly changing epoch.

This new operating system will, by necessity, be comfortable with loss. There is, after all, much to be gained from epochal, transformative change. In the midst of chaos and devastation on the scale of a world war, for example, we might discover how to breathe underwater.

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University Waterloo’s new Centre for Ecosystem Resilience and Adaptation

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Canada’s University of Waterloo is launching a new transdisciplinary Centre for Ecosystem Resilience and Adaptation

The new transdisciplinary centre will focus on conservation and restoration, protected areas and adaptation of humans and other organisms. Ecosystems, with their wealth of biological diversity, provide essential sources of food, materials and natural spaces for people.

The centre’s researchers, drawn from the natural, physical, mathematical and social sciences, aim to help decision-makers develop better policy and governance to buffer ecosystems against unwanted and unprecedented change. Their innovative ecological work to date has resulted in advanced ecological modelling, new conservation and restoration policies for parks and protected areas, and multiple approaches for integrated management of invasive species. The researchers are based at Waterloo and at other universities and organizations.

In the future, the researchers will focus on:

* how ecosystems respond in the face of changes created by human activities,

* how organisms within ecosystems adapt to change,

* when, and how, people should actively assist ecosystems in order to boost resilience, and

* how human activities should change in order to improve ecosystem resilience.

Researchers will investigate new approaches to prevent and repair damaged ecosystems in order to maintain or restore resilience. Also, they will probe the role of protected areas in facilitating ecosystem resilience and adaptation, along with the capacity for ecosystem components to adapt to changes in the environment.

Work at the centre complements the diploma in ecological restoration and rehabilitation offered by Waterloo’s faculty of environment. The diploma provides students with specific knowledge and opportunities to work on real-world projects.