The frustrations and importance of long-term ecology

Conducting field experimental ecology is a frustrating business. There is little debate that to understand ecosystem response to environmental change we need field experiments which last as long as possible. It often takes a long time to see any change and sometimes initial changes do not represent long-term response. The Park Grass experiment at Rothamsted in Hertfordshire (UK) is the world’s oldest ecological experiment, established in 1856 to finds ways to maximise hay yields. One hundred and sixty one years later it is still throwing-up surprises and producing Nature papers. It has become perhaps the most important experiment in ecology not because the treatments are particularly interesting (they aren’t) but because it has been going so long that we now have a huge wealth of data with which to test ecological theory. It is frustrating therefore that most funding agencies support research which lasts no more than about three years. In reality this means that researchers rarely have more than two seasons of data collection, and frequently less than that. Many field experiments end up being removed just as they are getting interesting!

In 2010 we established a climate change experiment on a peat bog in west Wales. We think this experiment is pretty neat. It is one of only half a dozen climate change experiments in boreal bogs globally (the only one on a UK raised bog) and has a unique pumping system for simulating summer drought. The experiment was initially funded through a European project (‘PEATBOG’) for three years. It took most of the first year to set up the experiment and most of the second year to optimise performance. While some things we monitored changed quite quickly, we saw little change in many others over this first two years. Despite warming the peat surface by a couple of degrees the plant communities did not change at all despite abundant evidence to suggest that peatland plant communities are sensitive to warming. It was clear that two years just wasn’t long enough. As the funding came to an end we were faced with the choice of whether to abandon the experiment or try to keep it going. We opted for the latter and there have certainly been days when I have regretted that decision! Myself and the other post-doc on the project both moved on and got other jobs. Fortunately my job gave me enough flexibility that I could keep making the long drive from central Scotland to west Wales to keep the experiment ticking over, but that could only ever be a short-term solution. Things took a turn for the better when we managed to get some NERC funding for a PhD studentship and recruited a brilliant student. The problem with getting funding for an experiment which already exists is that funders do not like to support pre-existing research… even if the original questions are still valid and interesting. Instead it is necessary to find new questions which can be asked using the same experiment. For us this involved bringing in a sea level dimension in our flooding-prone coastal site. All was well for a few years but all-too-soon the PhD was coming to an end and we were again faced with the prospect of either abandoning the experiment or reinventing it again. By this point we had started to see changes in some things which didn’t change in the initial period of the experiment. We began to see increasing abundance of White-Beaked Sedge, shading out the Sphagnum moss but this was only really apparent around the edges of the plots which experience the greatest warming. It was clear that we still needed more time to understand the ecosystem response. Again we foolishly decided to try to keep the experiment going. This time our reinvention involved trying to integrate palaeoecology with experimental ecology. As a palaeoecologist who somehow ended up doing experimental ecology this is an idea which is close to my heart and I think it is pretty important. However funding agencies haven’t always agreed! I was therefore delighted to hear last week that we have been successful in an application to The Leverhulme Trust. I will probably write more about this project in a future blog but one of the key outcomes is that the future of the experiment is now secure through to 2020. For now I just want to thank Leverhulme for the funding and urge you all to go out and buy Unilever products! I’d also like to take the opportunity to plug the PhD studentship which forms part of the project. This is now advertised and I would be really grateful if readers of this blog could help spread the word far and wide. Thanks! Details:


Leave a comment

Filed under Uncategorized

Kamchatka: Land of volcanoes, bears, bugs and bogs!

If you research peat bogs for a living then Russia is where the action is! Russia is the country with the largest total area of peatlands, the greatest expanse of peat (the West Siberian lowlands) and the biggest individual bog (the Great Vasyugan Mire, a candidate UNESCO world heritage site). In the last few years I have been working on Russian peatlands, travelling to Western Siberia in 2014 and the Leningrad Oblast in 2015. This summer a new Royal Society project with my colleague Yuri Mazei at Moscow State University gave me and a couple of my PhD students the opportunity to travel to somewhere even further afield: the Kamchatka Peninsula in the Russian Far East. Flying from Moscow to Petropavlovsk-Kamchatsky is an experience in itself and really brings home the scale of Russia; it’s an eight hour domestic flight and you haven’t even covered the full width of the country! From the moment you land at the airport it’s clear that you are somewhere a bit different with snow-capped volcanoes dominating the view. Petropavlovsk has been covered in volcanic ash several times in its history –most recently in 2013- and it’s easy to see why.

Our research project is about how bogs accumulate carbon and cool climate so we travelled to Kamchatka in search of its famous pristine blanket bogs. After a couple of days sorting out provisions and paperwork and seeing the tourist sights of Petropavlovsk (didn’t take long!) we headed off out into the wild. Kamchatka only has a few dozen miles of tarmaced road so getting around is something of a challenge. Our Russian colleagues had arranged an ancient ZiL truck and driver Alexei. This behemoth was an amazing piece of engineering: a huge lumbering beast but able to get into the most improbable places, and still sporting tyres proclaiming ‘Made in the USSR’!

The first leg of our trip took us west into the mountains and then north along ever worsening roads. Our colleagues had arranged for us to travel along some private roads so we were soon away from any sign of human civilisation and into proper wilderness. In contrast to other areas of the boreal zone the forests of Kamchatka are not of conifers but rather a species of Birch (Betula ermanii) giving them a more open feel. In common with other areas of the boreal zone however the forests are endless, only interrupted by the peat bogs. It didn’t take long to find our first bog and after that the bogs and the views just kept getting better. Blanket bogs are an unusual type of peatland where the peat ‘blankets’ the underlying topography. This type of bog is very familiar to us Brits because it is the type which covers our hills and mountains from Dartmoor to the Flow Country. However globally it is quite rare, only present in places with very maritime climates so this was the first time I had seen peatlands like this outside the UK. In the UK our peatlands have been trashed by peat cutting, burning, over-grazing and air pollution over many centuries but the peatlands of Kamchatka are some of the most pristine on earth with beautiful mosaics of Sphagnum mosses. Lovely!

We spent much of the first week travelling from bog to bog exploring the sites and their peat before deciding on the perfect site for our main efforts. In these remote regions there is no accommodation to rent, so we camped. I don’t mind camping but camping in Kamchatka bought with it the hazard of the dreaded Kamchatka mosquito: a huge and bloodthirsty beast which gathers in vast swarms waiting for that moment when you have to remove your layers of protection to eat dinner or go to the loo. Kamchatka’s more famous great predator is the Brown Bear with all the tourist literature proclaiming the incredible density of bears on the Peninsula. I took these claims with a pinch of salt at first. I have done a lot of fieldwork in Alaska where the tourist literature makes similar claims but I have only seen one bear in six visits. However I have to concede that the Kamchatka tourist board have this right as we ended up seeing eight bears over the course of our trip. We all learned the Russian for ‘bear’ quite quickly! The closest of these encounters was one afternoon when we strayed further from the vehicle in search of an unusual mire mentioned by a park ranger. As we were heading back to our campsite along an overgrown track we came across a large bear and her two cubs heading towards us. This was the closest I’ve ever been to a bear and they really are impressive animals and very very large. The first thing you are taught about bear safety is to avoid the mothers with cubs but the high vegetation had meant that we got fairly close to this group without them being aware of us, or us of them. We stopped and both groups inspected each other. We shouted but the mother just stood her ground while the cubs stood up on their hind legs craning to get a better look at these strange-smelling animals. Fortunately Alexei had bought his rifle and a few shots were enough to persuade the little family that they might be better off heading in a different direction leaving us free to resume our amble back to the campsite.

After several days coring and surveying our target site we headed back the way we’d come, resupplying and spending a pleasant rest day at one of Kamchatka’s many hot springs. The final leg of our trip took us north through better-travelled areas. Here we were closer to the volcanoes and our peat cores provided graphic evidence of the history of volcanic activity with thick layers of volcanic ash bracketing the peat. Another week of peat coring, this time with some nights in bunk houses rather than tents and we were soon heading back to Petropavlovsk. A touristic trip to the edge of the Pacific rounded off the trip.

So what were our final impressions of Kamchatka? It was very interesting to see a different side of Russia. The big cities these days are affluent, modern and self-confident but there was no getting away from poverty in Kamchatka. The people were very friendly but this really felt like a region which was dealt a body-blow by the end of the USSR and hasn’t quite recovered even after twenty five years. The first leg of our trip had a feeling of remoteness and true wilderness which is difficult to match. I feel privileged to have been somewhere that few Russians and very very few western Europeans get to go. The views of bears and eagles and sealions will stay with me for a long while, as will those views of stunning snowy mountains protruding above the sea of trees. We owe a big debt to our Russian collaborators for making this all possible.

Leave a comment

Filed under Uncategorized

New PhD position in peatlands/carbon/tephra

Following on from my last post, a PhD position to work on the impacts of afforestation on peatland carbon balance is now available at the University of York with a deadline of 18th October. This position forms part of our new Leverhulme Trust project. You can find the advert here: and this will soon also be on the departmental website The PhD is fully funded at standard research council rates with a duration of 3.5 years. If you’re interested and want to discuss this then drop me an email at

Leave a comment

Filed under Uncategorized

Is planting trees always a good thing?

One of the perks of being a peatnik is the chance to travel around and see cool bogs in interesting places (I’m writing this just home from Russia). Over the last few years I have visited quite a few bogs across Europe as part of a couple of research projects and this has really made me appreciate how damaged most of our bogs are in the UK. Although UK bogs are increasingly valued for their ecosystem services and we now have some of the tightest regulations on peatland exploitation it hasn’t always been this way. For centuries we have been cutting up our bogs for fuel, draining them for agriculture and burning them to encourage economically important species.

One of the most widespread ways we have damaged bogs is by draining them for forestry with 10-20% of all UK bogs planted with non-native conifer trees. In Britain after WW2 there was a desire to increase timber production and encourage employment in declining rural areas so expanding forestry seemed an appealing prospect. The UK at this time had (and still has) a very low cover of woodland by international standards. At the same time the revolutionary Cuthbertson Plough and better agricultural vehicles made it technically possible to grow trees in places which had never previously been feasible, including on peat bogs. Conifer trees were planted widely across Britain in one of the largest changes to the UK landscape since the Ice Age. Planting was encouraged by tax breaks and many famous people like Terry Wogan and Cliff Richard put their money into planting trees on bogs. The tax deal was so good that people made money just by planting the trees and in some extreme cases the trees were planted with no intention to ever harvest them; investors made a profit anyway.

Trees have been planted on bogs across Britain but nowhere more so than the Flow Country of northern Scotland. The Flow Country is arguably the only true wilderness left in Britain. The peatlands are vast and beautiful with amazing pool complexes that you just don’t see anywhere else in the UK. Peatnik heaven! But the Flow Country is remote and land is cheap so vast areas were bought-up by commercial forestry companies to plant trees. Large areas of bog were planted with Sitka Spruce and Lodgepole Pine with the scale of planting clearly visible in satellite photos. This was a huge environmental tragedy and incredibly recent; continuing into the 1980s. There is a remarkable David Bellamy documentary from this era with really depressing footage of pristine blanket bog being ploughed up. In recent years Bellamy has become a loopy climate change-denier but he was also a serious peatland scientist (lots of us own his book) and was at the forefront of the campaign to preserve the Flow Country peatlands. The controversy over the future of the Flow Country became an iconic conservation battle with conservationists scrambling to buy and designate areas of bog before the forestry companies could plant trees. The debate became very acrimonious and it’s often said that the very public role of the Nature Conservancy Council on the ‘anti-forestry’ side of the argument was an important factor in its disbandment by the government of the day.

The conservation argument of the 1980s was mostly driven by the impacts of afforestation on wildlife, particularly birds. In recent decades our motivations for conserving peatlands have changed and now conserving carbon stocks, as well as conserving biodiversity, is often an important motivator for looking-after bogs. Although we tend to think of trees as ‘good for carbon’, planting trees on bogs may not be a great idea. Peat bogs are stuffed full of carbon; dry peat is about a half carbon and the average bog is at least a couple of metres deep. Conifer plantations by contrast contain less carbon than you might imagine; if you shred a conifer plantation in situ you end up with a surprisingly thin layer of chippings. Although many areas of the world have naturally forested bogs where trees and peat happily co-exist, that is not the case here (although there are a few tiny areas). Trees don’t grow on our bogs because they are too wet and don’t have enough nutrients. In order for trees to grow foresters drain the surface and add fertiliser but this can also cause bogs to release carbon. The question is: how much? If afforested peat releases more carbon into the atmosphere than is captured by the trees then planting trees on bogs may be exacerbating climate change… but we don’t currently have the evidence to tell if this is happening or not. The Forestry Commission effectively banned new conifer planting on deep peat in the nineties and by then planting had already slowed due to the removal of the tax breaks in 1988. For now the big question is ‘what should we do with the plantations we already have’? This is the topic of a new research project supported by the Leverhulme Trust that we will be starting later in the year.



1 Comment

Filed under Uncategorized

Fieldwork in Russia


I’m just back from 11 days in Russia where I have been busy sampling lakes and peatlands with Russian colleagues. For a peatnik the key appeal of Russia is the vast area of peatland; the largest in the world (some people say Canada has more peat but I don’t believe that!). For those of us used to crappy British peatlands many Russian peatlands are also wonderfully undisturbed. We had a fantastic trip out to western Siberia last summer working on what is certainly the most beautiful peatland I have ever visited. Here in the UK we have some really excellent peatland science but hardly anyone works in Russia. Russia has the reputation as a difficult place to work; logistically, bureaucratically and practically. The recent onset of ‘Cold War 2’ hostilities certainly hasn’t helped either. However we can’t ignore these huge areas of bog so over the last few years I have been starting up some projects with Russian colleagues looking at both modern peatlands and their palaeoenvironmental history.

In this trip I was working with colleagues from Penza State University (where I have a visiting position) and the Institute of Limnology of the Russian Academy of Sciences. We spent a week based on an Ostrich Farm (really!) in Leningrad Oblast; that bit of Russia crammed between St Petersburg and the Finnish border. The main focus of this trip was sampling modern lakes and we clocked up thousands of kilometres of driving to sample more than twenty lakes. Russia is such a vast country that the landscapes vary hugely. This part of Russia is quite different to where I have been previously with extensive Scots Pine forest on thin, sandy soil (outwash plain?) with lots of (kettle hole?) lakes scattered around. The great thing about working with Russian colleagues is that they seem to have lots of people in their labs so the samples we took will be analysed for a whole variety of organisms and physico-chemical properties which should give a really great dataset. We also took a couple of cores. One of these goes back to the Late Glacial with lovely laminated lake sediments. The other is more recent and we are focussing on the transition from lake to bog, aiming for a really high-resolution multiproxy reconstruction. Hopefully there will be some exciting results; watch this space!

Leave a comment

Filed under Uncategorized

Plant biodiversity at risk from ‘safe’ levels of nitrogen deposition.

This is a blog on our research which originally appeared in The Ecologist magazine, here:

Over the last 100 years the global population has increased four-fold to seven billion people and may reach nine billion by 2075. How to produce enough food to feed all these people is one of the biggest global challenges.

Throughout the twentieth and early twenty-first century, food production has been dramatically increased by improving agricultural yields, particularly by applying nitrogen fertilisers. In 1908, the German chemist Fritz Haber invented a method for producing ammonia fertilizer from the inert nitrogen gas which is in the air all around us.

Haber’s discovery earned him a Nobel prize and paved the way for cheap, industrially-produced fertilizer. A miracle of industrial chemistry, today around 150 mega-tonnes of nitrogen fertiliser are produced annually and half of the global population would not be alive without Haber’s process.

However increasingly it is being realised that this huge benefit to human development comes at a high price. Human production of reactive nitrogen is now more than double natural nitrogen fixation and we have unwittingly conducted a huge global-scale experiment in geoengineering.

The problem is that the nitrogen we spray on our fields does not stay there in perpetuity – much of it is washed into rivers or evaporated into the atmosphere. In water-bodies, nitrogen causes algal blooms that kill fish, impair drinking water quality and reduce aquatic biodiversity. In the atmosphere nitrogen from agriculture combines with oxides of nitrogen produced by burning fossil fuels.

In the UK, levels of this nitrogen pollution are often more than ten times higher than the natural background and scientists have observed acute nitrogen deposition events even in the remote Arctic. Atmospheric nitrogen is a severe threat to human health, reducing the life expectancy of at least half of Europe’s population by six months or more. Increasingly scientific research shows that nitrogen deposition is also a serious threat to ecosystems.

A paper just published in Proceedings of the National Academy of Sciences shows the impacts of nitrogen deposition in the environment may extend even further than previously thought. Dr Richard Payne and Professor Nancy Dise, of Manchester Metropolitan University, together with colleagues at Lancaster University and the Open University, studied more than 100 individual plant species’ reactions to nitrogen deposition at 153 grassland sites across Europe.

The scientists found that many species, particularly wildflowers such as creeping buttercup, harebell, yarrow, and autumn hawkbit, were much less abundant in areas with high nitrogen levels, such as central Britain, the Netherlands, northern Germany and Brittany. But particularly surprising was the discovery that many species declined at very low levels of pollution, often below the legally-recognised ‘safe’ level.

Professor Dise said:  “One of the drawbacks of previous studies is that most field experiments to establish limits on pollution are near the populated and polluted areas where most scientists live.  It may be that long-term exposure to even medium levels of pollution have already changed these ecosystems. In this latest research, we studied many grasslands along the natural gradient of pollution across Europe.  And we found that at even relatively ‘clean sites’, low levels of pollution had an effect on the abundance of some plant species.”

This surprising result shows that even areas a long way from pollution sources and previously thought to be free from air pollution impacts may have been affected.  But this is an environmental concern that most people have never heard about. Dr Payne said: “We have been very good at communicating the problem of climate change and carbon emissions but have failed at communicating the nitrogen problem. Until the public are aware of the issue then policy makers are unlikely to take action.”

The scale of the problem is huge. It has been estimated nitrogen pollution costs the countries of the European Union alone up to €320 billion a year- but progress in tackling it has been limited.

Over recent decades many developed countries have been quite successful at reducing nitrogen produced by fossil fuel burning; UK emissions of nitrogen oxides are down by almost 60% over the last 40 years. But tackling agricultural emissions has proved much more difficult. Nitrogen fertilizers are essential to feeding the world’s population but we can try to reduce the amount we use and the amount we lose into the environment.

The production of meat and dairy products contributes disproportionately to the nitrogen problem: nitrogen is released in the production of crops and then more nitrogen is released when these are fed to animals. In western countries we consume more animal products than is necessary for a healthy diet; if this can be reduced it would have big environmental benefits.

At the same time, better agricultural practices such as improved techniques for manure spreading can more than halve nitrogen emissions, as well as saving money. The Netherlands has some of the highest levels of nitrogen deposition anywhere in Europe but have achieved big reductions by legislating for low-emission farming techniques.

It is clear that the nitrogen problem isn’t going to be solved quickly, which poses the question – if we must have nitrogen pollution where should it be?

Payne and Dise’s research might hold an answer. Dr Payne said: “We found that lots of species are lost with only a little pollution but once the ecosystem is very polluted adding more pollution doesn’t make much difference”.

This suggests that to conserve as many species as possible new pollution sources should be put in areas that are already polluted and degraded to avoid any new pollution in currently unpolluted areas.

Leave a comment

Filed under Uncategorized

Environmental History vs. Palaeoenvironmental Science: Two disciplines. Two cultures. The same questions?

A blog originally written for the Environmental History of Russia blog:

Having recently joined this network I was invited to write some introductory text about my research. In contrast to the majority of members of this network I’m a scientist and my work particularly focuses on reconstructing past environmental change. In the last couple of years I have started to work in Russia. Rather than bore you with too much detail about peat bogs, testate amoebae and age-depth models I thought this post might be an opportunity to jot down some thoughts about the relationship between palaeoenvironmental science and environmental history. This is entirely a personal perspective informed solely by an occasional peek at environmental history literature and the odd chat with historian colleagues over a beer. I’m not claiming any particular insight and am probably betraying my own ignorance… but maybe there is an interesting conversation to be had here.

So firstly it is perhaps worth saying what exactly I mean by palaeoenvironmental science. I use this as a catch-all term covering a variety of sub-disciplines which all have in common the attempt to use natural archives to understand what the environment was like in the past. Within this the methods we use and the questions we try to answer vary greatly. One of the main aims of my own research is to understand what climate was like in the past using material preserved in peat bogs. Peat bogs are useful because rates of decomposition are slow and accumulation of peat gradual. To produce a record of climate change I will take a core from a bog, use radiocarbon dates to work out how quickly the bog accumulated peat, extract and analyse the preserved remains of organisms which grew on the bog in the past and apply a statistical model to tell me what that means in terms of climate. Other researchers might for instance use tree rings to understand the environmental impacts of a volcanic eruption or analyse coral to understand changes in ocean acidity over thousands of years.

The ways in which past human societies have modified and utilised the environment are often important questions for us. We might, for instance, use charcoal particles in East African wetlands to understand how Palaeolithic people burned savannahs, use microscopic algae to reconstruct how Victorian tourism led to nutrient pollution in lakes or use tree rings to investigate radioactive leakage from Chernobyl. Less frequently our aim may be to investigate how humans were themselves affected by environmental change; we might for instance use pollen to look at how agricultural practises were affected by climatic cooling in the Little Ice Age. In a recent review of ‘key questions in palaeoecology’ (an important sub-discipline of palaeoenvironmental science) almost a quarter of the identified questions had clear links to human activity. Even when humans are not central to our questions we often need to consider their role. If our aim is to use plant macrofossils to reconstruct 5000 years of climate change in Russia we need to consider the possibility that ancient humans, not climate were the reason for any change we identify.

The terms palaeoenvironmental science and environmental history are essentially synonyms; both really mean just ‘the history of the environment’. However the two terms are handy titles for two quite different disciplines, one in the sciences one in the humanities. These two disciplines have different research practises and different research cultures but the interactions of people and their environment through time is a key question in both. Both palaeoenvironmental science and environmental history recognise the need to know what happened in the past in order to understand the present and plan for the future. It seems to me that the questions we are interested in are frequently the same, or at least frequently overlap.

However the relationship between the two academic disciplines is not close. While environmental history sometimes claims to be an interdisciplinary subject a glance at the content of environmental history journals or the membership of professional societies suggest that engagement with science is pretty limited and this is particularly true of palaeoenvironmental science (arguably the branch of science with most to offer). It seems very rare to find an academic who self-identifies as an ‘environmental historian’ outside of a history department. Of course there is a grey area between the two disciplines. Palaeoenvironmental scientists sometimes call what we do ‘environmental history’ and we sometimes even use documentary sources but I suspects that our aims in doing so, and our approach to those documents, contrast with that of a historian (with a strong emphasis on quantification).

The key difference, of course, is in how we consider people. As palaeoenvironmental scientists what people thought about their environment or why they attempted to change it are not our primary interest. Our records can only tell us about the products of human actions, not their motivations. Similarly, our records can tell us something about how natural environmental change effected people in the past but not what those people thought about it, and our ability to understand the mechanisms by which changing environments influenced human societies is often limited (and can tend towards the deterministic). In environmental history people always have a central role either as an agent of environmental change, a responder to change or simply recorders of change. This is not the case in palaeoenvironmental science. While the role of humans in environmental change is often important, this is far from always the case and for some time-scales and some questions can be safely ignored.

There is also an important difference in the temporal scale. Palaeoenvironmental methods allow us to reach much further back in time than the oldest historical records; to the evolution of humanity and beyond (although most records are much more recent). This not only makes historical records irrelevant to some of our questions but also perhaps gives us a different perspective on time itself. The temporal scope of a palaeoenvironmental study is rarely less than a century and typically many millennia. That of environmental history is typically a few decades and rarely more than a century or two.

Most fundamentally our two disciplines lie on either side of the ‘two cultures’ dividing line; one in the sciences and one in the humanities. The inherently qualitative nature of historical research is problematic for scientists; I like to have a P-value for my conclusions! The roots of environmental history within environmentalism is also a complication. The notion of scholarship with ‘an agenda’ sits uncomfortably with our scientific aim to be impartial observers (however unachievable that aim may be).

There is an interesting contrast between the relationship of palaeoenvironmental science with the discipline of environmental history and that we have with archaeology. In general I think it is fair to say that we are much more comfortable talking to archaeologists, and much more familiar with doing so. Archaeologists use many of the same methods and share many of the same practical concerns (such as the perennial problem of establishing reliable chronology). We work on similar time-scales and the relevancy of our results for each other is perhaps clearer.

In my opinion the relationship between environmental history and palaeoenvironmental science is unlikely to ever be close but there are certainly occasions when we are interested in similar questions and our results have relevancy to each other. Of the five key foci of the ‘Russia’s Environmental History’ research project, at least three would be amenable to methods from palaeoenvironmental science (exploitation of natural resources, environmental disasters and nature conservation).

Leave a comment

Filed under Uncategorized