Introduction to Ecosystems
Thank you for sending in questions for the live session on 20th March which you catch up on in YouTube. There were lots of fascinating questions and I have tried to answer as many as possible either here or in the live session. Do continue the discussion that the questions have generated in the comments below.
Anneke: Could you name your top 5 threats to global biodiversity in order of priority, eg climate change, human population growth, decline in pollinators, spread of non-native invasive species, intensification of farming, spread of plastics in water and soil, increase of built-up land (buildings/roads). I realise most of these overlap, are each other’s cause or effect etc, but still, would like to hear an expert’s priority listing.
David Robinson (DR): There are an awful lot of threats to global diversity so I suspect that we won’t all have the same list, but here is mine:
- human population growth
- unfettered demand
- exploitation of natural resources
- lack of education.
James : Hi Dr. Robinson ! Would you say that human pollution could very well cause a chemical reaction that could result in genetic mutations of plants and animals within an ecosystem? If so, how should we be concerned about it and hopefully try to prevent the mutation from spreading?
DR: Chemical pollution could provide a selection pressure that would influence evolution. Also, hormones released into the environment have affected salmon. If a pollutant was mutagenic (causing mutations) it might be difficult to prevent an advantageous mutant spreading through natural selection. However, most mutations have negative consequences.
Jack: Do you have any advice on talking to politicians about environmental issues?
DR: Do plenty of research so that you are on top of the subject. A lot of politics is not evidence-based, but it should be and for us as scientists, evidence is fundamental.
Deborah: Humanity is increasingly living beyond our means – we currently consume 50% more natural resources than the Earth’s ecosystems can replenish. Dr. Robinson, please can you give the forum 5 key things we can do at home and in our close by ecosystems for sustainable living?
DR: My five suggestions are – walk, cycle, upcycle and recycle, actively thermoregulate, buy local. By ‘actively thermoregulate’, I mean that if living in a cool environment (like the UK and N Europe, for example) use clothing layers rather than heating to keep the body at optimum temperature.
Melanie: We heard that movement is difficult for phytoplankton and yet they migrate in a vertical direction on a daily basis. How do they achieve this?
DR: Most phytoplankton are motile, as they have flagella. However, vertical movement in the water is mostly through transport by currents.
Olwen: This year’s farm Single Payment Scheme rules do not promote a diverse ecosystem as trees, gorse, bracken and blackthorn are classed as ‘ineligible features’, thus not gaining agricultural status. Do you feel this government policy will harm our countryside diversity?
DR: I think that there is good evidence that agriculture does affect diversity and that the funding system even discourages diversity. For example, in the Cross-compliance Regulations, farmers must prevent ‘unwanted vegetation’ from growing on their land, even if their land is producing nothing. So, they must cut, graze or spray it with herbicides to get their money. This rule has particular effects on upland areas which continue to be bare of diverse vegetation and trees, leading to more rapid surface run-off of water.
Carol: I’d be interested to know your views on the translocation of ancient woodland and soils as mitigation for planning applications which would destroy the original site if implemented. Is the process of translocation justifiable, and what percentage loss (or range of loss) of original features might one typically expect?
DR: Translocation of animals and plants is not easy and personally, I doubt its effectiveness but have not located any references that have specifically analysed success and failure of translocation projects. I have seen some pretty depressing (unpublished) figures for decline in translocated newt populations. See also June’s comments below.
June: I have recently been reading Dr Oliver Rackham’s ‘Woodlands’, where I was surprised and saddened to find that it is very hard or indeed impossible to establish new woodland with its attendant flora, particularly on previously farmed land. Although I was angered by Owen Patterson’s biodiversity offsetting plans and realised that planting a few trees is no replacement for an ancient forest, I was still under the impression that we could plant fairly good and biodiverse woodland. Given the work by Dr Lee Su See in Malaysia with mycorrhizal ‘wood wide webs’ and other research, could we perhaps be more hopeful that we could reinstate or plant new biodiverse woodlands in the UK?
DR: Oliver Rackham also made the point that sourcing trees globally rather than locally also sources pathogens globally, with often catastrophic results.
Deborah: Step 4.1 spoke about Flu not being specific to humans but using many animal hosts. It got me thinking, can people catch kennel cough from a dog?
DR: Kennel cough is caused by Bordetella bronchiseptica, a bacterium. There are also viruses that make dogs more susceptible to infection. It seems to be possible for humans to be infected with the bacterium, but I have not found any publications that provide evidence of human’s contracting kennel cough.
Paul: Do the fungi in the woodland improve the soil for all seedlings, whatever the species? Or is there some recognition and promotion of growth to the saplings of the host tree? If it were the latter, it would suggest a closer symbiosis, would it not?
DR: The fungi in the soil link trees to seedlings and a fungus that is specific to one species is likely to be carrying nutrient to seedlings of the parent tree and others of the same species. The connection is a direct one, so it isn’t that the fungi are enriching the soil directly.
Francesco: Are there any cases study in Europe about using fungi in contaminated places as tools to enhance the soils and the ecosystems?
DR: You might find this paper interesting as it describes how a fungus can break down pesticide residues. http://www2.cnrs.fr/en/1561.htm
Dean: Conventional agriculture is responsible for a large proportion of the biodiversity loss we have seen in recent times. However, GM intensifies this trend by supporting singles species with toxic chemicals, which feed the plant but does nothing for the long term health of the soil.
What is your view on this? And why isn’t there any news on this issue?
DR: GM is a technique and its effect depends upon what the modification is intended to achieve. GM crops may help conserve diversity. An example, from South Africa, is a modification that makes a crop plant poisonous to insects that feed on it. By removing dependence on spraying to keep the crops clear of herbivorous insects, other insects are not affected. Incidentally, in the South African example it reduced human deaths from misuse of pesticide sprays.
Marie: There has been little news about genetic modification in farming. I seem to recall a very early paper on the effect on wildlife in that those crops that are genetically modified do not require pollination in the natural way. A downside of GM farming was identified as making any insect that visited these crops, infertile. Do you have any opinion or up to date information as if this is so, then this method of farming is detrimental to ecosystems for insects/pollinators?
DR: Some early concerns were about particular GM crops which were designed not to set seed, preventing spread into the wild. Farmers that used this GM crop were then tied in to buying new (and possibly high cost) GM seed from the supplier each year. GM as a technique is very valuable. However, each use has to be properly evaluated and some applications will have too many negative features while others are very positive in their effect
Khima: I am monitoring the vulture population in my city and have a very good sighting of more than 300 individuals of 3–4 species on a single site. Please suggest to me how we could sustain the population at that site? What are the measures I have to follow?
DR: Difficult to answer. Diclofenac used as a veterinary product was the cause of decline. Wild dog population has increased so now they are in competition for food with vultures.
Alison: Are there courses like this being set up schools to educate the younger generation?
DR: I am not aware of schools using this type of course.
Lindsey: What areas in Britain would it be possible to re-wild and do you think it will ever happen?
DR: Re-wilding is difficult but not impossible. Have a look at what Trees for Life in Scotland are doing (http://treesforlife.org.uk/ ). Wales Wild Land Foundation is another example of attempts at rewilding (http://www.cambrianwildwood.org/ )
Lindsey: Here in Wales we have brought the Red Kite back from the brink. In the early 1970s, I believe there were only 12 breeding pairs and our joy at seeing one was huge. The other morning I counted 5 on a 3 mile car journey. I see several every day. Have there been any studies on how their huge increase has affected the other species? I am sure I do not see so many buzzards as I used to.
DR: I have not found any studies on the impact of red kites on other species. I am seeing more buzzards than I used to and I also see plenty of red kites. However, these are just my observations. This year for the first time I saw two red kites circling over my garden, and for several days in a row. It is a great example of a successful re-introduction. It is not working so well in Scotland and there are suspicions that humans might be the cause.
David: Do we have many ecosystems that we know little about?
DR: Deep ocean ecosystems are not well studied for obvious reasons.
Wisdom: Describe one way in which species’ extinction can begin in ecosystems, and one way in which a species can be restored after destruction. Give a recent example in each case.
DR: Natural extinction can come about because there has been a change in some part of the ecosystem that an animal or plant cannot adapt to. Human activity, for example, may remove part of an ecosystem, like scavengers – examples are the shooting of red kites in the UK and the poisoning of vultures (via cattle carcases) in India. In both cases, protecting the scavengers may allow their populations to recover.
Diane: I understand that ecosystems are reliant on a constancy of factors, but in this fast-changing world is it not conceivable that the micro ecosystems on which we and all life are so dependant will be changed beyond repair? What can we do to stop or slow down this damage and can it be reversed?
DR: The problem with ecosystems in general is that we rarely have complete knowledge and so it isn’t easy to spot damage and know how to reverse it. Diversity can make natural systems resilient and natural selection does drive responses to changing conditions.
War: I think ecology is a great course. In an ecosystem, green plants are primary producers, herbivores and carnivores are primary and secondary consumers and then the highest level are people that feed on all levels to bottom. How can we know the whole ecosystem in water and terrestrial life of mode in food chain and food web?
DR: It is very difficult to chart all the links and interactions. It is also worth remembering that we define an ecosystem in terms of energy flow and that the concept of an ecosystem is a human construct that enables us to study and understand the world around us.
Duane: In trying to define ‘ecosystems’ we have started from a biological or species perspective. Little has been made of the ecosystem perspective, where every living ecosystem is driven and fuelled by atmospheric energies ~ sun, wind, water and gravity. Plants and photosynthesis are major components as well as co-evolution with other organisms. How do we study the interdependency of systems over time and space? Will we be looking at how we can map complex open ecosystems spatially?
DR: We did define ecosystems in terms of energy flow, which includes atmospheric energies. Studying interdependence in terms of time and space is difficult, of course, but something that we need to do, despite such studies taking many years.
James: I read about a theory that the natural world vibrates at a frequency of 528hz, and that this vibration can impact the psychological aspects of mankind for the better. Do you think that the study of ecology will, in the future, start to focus more what we consider to be the peripheral scientific theories like this , or will it continue alongside the long-established linear paths laid down by Banks and Darwin?
DR: Theories have to be tested and remain just ideas if they cannot be verified from evidence. The 528 Hz theory is, as far as I know, not sufficiently evidence-based. I can’t really predict what peripheral theories might emerge in the future.
Steve: I have recently studied FutureLearn courses on renewable energy and on fracking. Do you think enough thought is given to ecosystems, and their conservation, when planning applications are assessed for energy supplies? Off-shore wind and tidal schemes have been in the news, in the UK, very recently.
DR: I don’t think that sufficient thought is given to ecological considerations in many planning decisions. For example, short term (in planet rather than human timescales) often dominates and the long term consequences are not considered – or considered relevant.
Martin: In an earlier lecture, the concept of succession was introduced. My question resolves around man’s perceived need to ‘manage’ ecosystems. Is this an absolute necessity or can we (should we) leave ecosystems to their own devices?
DR: This is a hard question to answer because small remnants of once extensive systems will probably need management. However, the ideal is to leave systems alone to re-establish themselves, after the initial set-up, and this might work well in some cases where trees are being planted on hillsides. Our lack of megafauna in the UK can make continual management of herbivores necessary.
James: We as humans pose the greatest threat but, somewhat strangely, are also the greatest hope for the survival of the planet (our intelligence v. our morals). Have we reached the point of no return for the planet, and if not, how close are we to doing so?
DR: No, I don’t think so but we do have a large problem to contend with and that is that both the numbers of humans and their demands are such that human impact is a global threat. The planet will survive, of course, but it may become a very different place. We can all make a difference individually and as groups. I commented earlier about short-termism being a problem and we have to find a way of enabling our societies to take a very long term view, because the damage that we are doing to the planet requires long-term solutions. Re-wilding is an example of something that we need to do that will take a long time.
This question generate a number of additional comments (below)
Elaine: I think we are in trouble because those with power to make a difference seem to have no morals when money is brought into any equation.
Gabrielle: But I would argue, Elaine, that each of us individually, and also many of us in combination, can make a difference. But then I’m known as what is called ‘an unreasonable’ person who believes in a vision no matter how unpromising the prospects may be for realization.
Duane: Visionaries are like guiding lights providing simple ways to solve often complex problems.
Luana: I would like to know Dr Robinson’s opinion on this matter too, James. I agree with Gabrielle that individuals can (and must…) make a difference, but also with Elaine that also “those with power” should take environment more than money into account. A dream.
Brigit: I don’t know how far things will go before we reach a tipping point of some kind, but the closer we get, the higher the stakes – and the higher the stakes, the more we (who recognise the damage being done) need to up our game. I notice more and more people every day waking up to this fact and that gives me great hope. Hope is a wonderful motivator! My understanding is that we may already have crossed the threshold regarding run away climate change with our past actions, but we don’t know this for sure. Climate models contain many variables and there are still aspects we don’t fully understand. In the mean time we can do a great deal to help increase biodiversity by allowing more areas to re-wild. Then, whatever happens to the human race, we will at least have left some natural ecosystems behind us to continue evolving as they might have done had we not intervened so much in the first place. I know it’s way more complex than this, but I feel sure that re-wilding is somehow extremely important I’m very interested to read Dr Robinson’s reply to this question
Rebecca: I’m pretty confident whatever happens to humans, nature will take back the Earth. Life has survived through five major extinction events before, if humans are going to cause the sixth, life will persist. I like to think that eventually we will find a way to live completely off clean, renewable energy, and will have perfected sustainable practices, but the main question is, will we do this in time? Or will things get so bad that the world suffers, large parts of the Earth will become uninhabitable, leaving the habitable parts overpopulated and over-polluted?
Brigit: Himalayan Balsam is the bane of many waterways and related habitats in the UK. However, it provides an extremely valuable and much needed forage resource for the Buff-tailed bumblebee which (because of warmer winters) has recently begun to establish winter colonies rather than going into hibernation. I appreciate the negative impact HB is having upon our native river banks and riverside flora, but what happens when an invasive species like this becomes so valuable to one of our native species of (in this case) bumblebee, that its elimination would impact negatively on that species? How do we balance this out?
DR: HB highlights the problems of dealing with invasive species. The standard answer would be that the native species is not dependant on the invasive so we should remove the invasive one. Removal of HB is difficult as the seeds survive for a long time in the soil seed bank, but I think it should really be removed because of its overall effect on habitats.
Andy: During election time we’ll probably hear lots of messages that £1 spent on an early social initiative will save £x later on the crime bill. Are there any ecosystem cost–benefit analyses out there that may persuade politicians / economists to act together as they seem to like such sound-bites?
Gill: There is a big push on getting UK politicians to take this seriously, with a campaign for a Nature & Wellbeing Act http://www.wildlifetrusts.org/NWA in the next parliament which would recognise the value of nature in terms of ecosystem services and also health and wellbeing, crime and so on – it’s been calculated that the right progressive, enlightened approach to valuing nature could save the public purse £33bn a year in the UK.
DR: You both raise some interesting points. George Monbiot (www.monbiot.com ) does highlight the costs of agricultural and environmental projects. He has pointed out in recent articles that the UK government has argued against the €300,000 cap on subsidy payments to individual farmers and has also nearly doubled the subsidy for grouse moors (from £30 per hectare to £56). He argues that subsidies damage the environment, are grossly unfair and very costly.
Dr David Robinson
Thank you everyone for your questions, it was fantastic to speak with you, and I hope that you enjoy the final week of the course!
Dr David Robinson
Introduction to ecosystems