The most devastating impact on biodiversity is caused by agriculture. Farming is already the greatest extinction threat to birds, and its adverse impacts look set to increase, especially in developing countries (Green et al. 2005).

Thus one of the global challenges for the next century is the need to develop high-yielding varieties that require minimal inputs, so that impacts on biodiversity can be minimized.

An alternative to the “high-input” approach is to expand the number of organic
farms. Because organic farmers do not use synthetic pesticides, their farms support
higher levels of biodiversity than conventional farms. Some organic farms can yield as much, for some crops, as conventional agriculture (Reganold et al. 2001; Maeder et al., 2002), although in some cases the yields of organic cropping systems is considerably lower than that of conventional or integrated cropping systems (Bruulsema TW et al. 2003;
Maeder et al., 2002)

In cases of low yield, organic practices would require more land be farmed to maintain and increase output levels, thus potentially leading to reduced overall biodiversity. What is the net effect on wildlife when the land being converted to wildlife-friendly farming has a lower yield, and so more land, somewhere, must be farmed to provide the same harvest?

A new study this week published in Ecology Letters seeks to answer this question. The research indicates that when the organic yield per hectare falls below 87% of conventional yield, wildlife does not benefit.

The researchers surveyed Sixteen 10 × 10 km landscapes in the Central South West and North Midlands of England. Within each landscape they surveyed one organic farm, one conventional farm, and one grassland SSSI (Site of Special Scientific Interest: a UK conservation designation). They then counted butterflies in each area.

A few of the butterflies surveyed are shown here:

Thymelicus syvestris, Ochlodes venata, Erynnis tages, and Pieris napi (my favorite).

i-285e51ba916be49aed55d0069cae57b7-hasfarit_hanashran.jpeg

i-9717b2ca00b1967fe5094944e6d27890-OCHLODES-VENATA.jpeg

i-18c6bd07eb457d1183f2d354a503048b-Erynnis_tages_1858.jpeg

i-ca2d40a736bcb4fc8c4a60dca797b25c-Pieris_napi(Bielinek_bytomkowiec).jpeg

They found that, for the type of fields and farms investigated, organic farms support a higher density of butterflies than conventional farms, but a lower density than grassland reserves. Organic farms support more butterflies than conventional farms, so if there were no difference in yield it would always be better to farm organically. However, the lower the organic:conventional yield ratio, the more advantageous an alternative land sparing strategy would be.

What this means is that even if we convert ALL of agriculture to organic farms (now only ca. 2% in the United States), we still need to increase yield on these farms if we want to spare land and protect wildlife. The study also suggests that if our goal is a sustainable farming system, we may not be investing wisely. The authors indicate that in the UK alone, £435 m was spent on agri-environment schemes in 2008, as compared to a budget for all other nature conservation of c.£80 m. More interdisciplinary research is urgently needed on how the net benefits of different farming methods compare, so that agricultural policy can be as environmentally sustainable as possible. And, as readers of this blog will not be surprised to hear me say, we need to use the most effective modern genetic methods to increase crop yields on ecologically managed farms.

Hat tip to Stephen Daubert, author of “Threads in the Web of LIfe” for alerting me to this paper.

Comments

  1. #1 Arraial dajuda
    November 4, 2010

    I totaly agree to expand the number of organic farms, but are people willing to pay the price?

  2. #2 red pepper
    October 13, 2010

    The paper shows a single location (ouch) 4 rep (not bad for 1 location, but not awesome) relatively small plot (1mx1m) field experiment which was vandalized (which to me suggests the data isn’t that viable – the paper argues otherwise however) – also they claim to have repeated the experiment the enxt year sans damage – which if this is the case why use the data from a bad year?

  3. #3 Vene
    October 11, 2010

    Yes, conventional farming (called “conventional” not because it has been used the most throughout history, but because it is the convention in 2010) releases a lot of nasty pesticides and herbicides. Guess what, organic farms also use them, they just use “natural” poisons. For example, look up rotenone.

  4. #4 Ewan R
    October 6, 2010

    Piney @#17

    Industrial agriculture puts herbicides and pesticides into our soil and water

    the extent to which pesticide and herbicide runoff effect the ecosystem should (and I believe are, at least in other papers I’ve read – notably a modelling paper in science not too long ago which hypothesized exactly what the butterfly paper shows) be taken into account – but then so should the effects of herbicides and pesticides (and their runoff) which are utilized in organic ag.

    Because the destruction to biodiversity that industrial agriculture inflicts far exceeds the amount of land it uses.

    A citation is needed here I think – while this may be the case it isn’t necessarily so, and I’d assume that there is some level of yield balance (which may or may not be equivalent to that portrayed in the paper under discussion) at which point the scales tip.

    stripping the soil of life system that creates nutrients for plants. Therefore requiring industrial fertilizers which leaches into the water table and threatens our water supply.

    Organic (at least as far as I understand it) requires fertilizers (manure etc) which leach into the water table and threaten our water supply – at least at any sort of level of farming which can even vaguely be considered on the same playing field as “conventional” in terms of yield – I recall (although can’t find in the time available) that C. Benbrook’s work on improving organic systems to yield equivalent to conventional (in a given year at least) showed that nitrate runoff over a 10 year (or somewhere in that range, it was a pretty impressive timecourse experiment) period was equivalent between the conventional and organic system – so playing the nutrient runoff game really doesn’t hold much water, nutrients (particularly nitrate) are spectacularly mobile and tend to leach out of a field if you happen to look at them the wrong way – doesn’t matter if you apply ammonium nitrate & urea or if you apply cow poop – the nitrogen becomes nitrate, and nitrate has a habit of buggering off at the drop of a hat.

    Finally to address Sharon’s first comment

    But land not used for agriculture, except in areas of natural prairie, doesn’t actually convert to grassland reserve in any natural sequence. What it converts to is forested land – I’m not clear on what the advantage of comparing grassland reserves is, since agricultural land is unlikely in the US, at least, to revert to such land use.

    That’d be an issue if the study was in the US, it isn’t however, from experience (tho not backed by any literature as of the now, and possibly biased by growing up in North East England and extreme North East Scotland (10 steps further north and you’re in the sea)) non-cultivated areas in the UK remain pretty treeless and wild looking for years, possibly a throwback to cutting down the entire tree population of the country to wage war against neighbours and pesky Europeans.

    As Dunc suggests it may be likely that vast tracts of land left unfarmed may well revert to housing (although green belts around cities, if correctly enforced and maintained (unsure how this is going, before I left the UK it appeared that the whole system was about to fall on its ass due to the torification of the Labour party) would prevent this (and arguably have in some areas)) but I think the paradigm that looking at ag in this light is trying to push ag towards is farms with self contained biodiversity hotspots – a pipe dream most likely, but imo another option which could be added to the various forms of agriculture used – *if* it was shown that biodiversity and environmental impact was lowest in a high-input type non-organic setting which was 60% farmed and maintained with the other 40% left to go wild would it not be more responsible for those who currently push for all organic to instead adopt this method – producing the same amount of food but benefitting the environment even more than either of the methods currently put forward (when the issue is simplified down to 2 at least) – I feel that currently this approach isn’t one that anyone on either side (once false sides have been built) would consider – conventional farmers because you’d lose money, organic farmers because stepping outside of the enshrined code of organic is anathema and witches must be burnt (if that isn’t hyperbolic and strawmannish enough for you I can try harder next time)

  5. #5 Ewan R
    October 6, 2010

    Better link for comment #20 is
    http://www.plosone.org/article/info:doi/10.1371/journal.pone.0011405

    which links to the actual article rather than just commentary on the article.

    It’s not overly surprising to see a GM variety perform poorly in the field compared to conventional – this happens all the time – one of the big challenges in agronomic traits is to get events with efficacy (in the case of the wheat experiment efficacy = mildew resistance, which they apparently got in spades) and yield parity (which the greenhouse suggests should be the case, but which the field trials suggest probably isn’t the case) – you categorically cannot take the yield results of one GMO and apply this across all GMOs (just as you can’t take any set of data for GMOs and apply it across all GMOs – a case by case basis is required) – I have a feeling that this finding illustrates another issue with public funded research producing viable GM lines – not only is the regulatory hurdle massive, but in order to demonstrate yield parity large scale trials are an absolute necessity (I can’t go into detail on the size of trials industry uses, but suffice to say the trial size in the paper is absolutely pitiful by the standards I am used to)

    The paper shows a single location (ouch) 4 rep (not bad for 1 location, but not awesome) relatively small plot (1mx1m) field experiment which was vandalized (which to me suggests the data isn’t that viable – the paper argues otherwise however) – also they claim to have repeated the experiment the enxt year sans damage – which if this is the case why use the data from a bad year?

    Breeding
    trials to select lines for further investigation do not need full
    replication and randomization, yet for an assessment of the
    ecological behaviour of such lines, replicated and randomized
    ecological experiments would be required. Our study may serve as
    an example of potential results that can be obtained in such
    experiments. We believe that such experiments can help us to gain
    a deeper understanding of single-gene effects in plant ecology and
    evolution.

    (sorry for messy formatting – Pam’s twitter box is in the way! Bad twitter box!)
    is the final line from the conclusion of the report – this paints an inaccurate picture of selection of transgenics in industry – multi location multi rep field trials categorically are what is utilized at the proof of concept level for literally hundreds of genes – other supporting data is also gathered, but it is acknowledged in the industry (at least in Monsanto – I think Pioneer is more heavily invested in greenhouse results in their fast growing corn, although this is possibly just a rumour) that without powerful multi-loc multi-rep (and preferably multi-year) data that advancement of any gene or set of genes quite frankly doesn’t make sense commercially (whereas academically the issues of non-yield parity are something that you’d want to deal with later on after you prove efficacy of the trait in question – which apparently was a resounding success in all cases for the wheat in question)

    Anyway, that’s my bit on that… apologies for continuing to take the discussion completely off track – that’s what happens when an interesting article is cited I guess

  6. #6 Nogmo
    October 4, 2010

    I wonder how much money the author receives in grants, lab equipment, etc, from the GM community?

    foodfreedom.wordpress.com/2010/07/18/new-study-gm-wheat-yields-48-56-percent-less-in-field-experiments/

    New study: GM wheat yields 48-56 percent less in field experiments
    A new study out of Switzerland reveals that the performance of GM crops in the glasshouse differed significantly from their performance in the fields. GM field plants had significantly fewer seeds and lower yield than control plants, and were more susceptible to infestation, summarizes Devinder Sharma.

  7. #7 darwinsdog
    September 29, 2010

    Posts #16 & #17: Perhaps so but the issues you address are beyond the scope of this study. It’s unreasonable to criticize a study over issues it was not designed to explore.

  8. #8 yazmak
    September 29, 2010

    Essentially, an experimental validation of the Borlaug hypothesis (essentially, that one of the best things you can do to help the environment is make farming more efficient, so that less land is used for it). Interesting.

  9. #9 Piney
    September 28, 2010

    This article is grasping for straws.
    First of all, to lable industrial agriculture as “conventional agriculture” is misleading considering we have only used industrial methods for three quarters of a century. Second, its is entirely inaccurate to reduce the situation to a simple equation of Organic= reduced production= more land= less biodiversity. Because the destruction to biodiversity that industrial agriculture inflicts far exceeds the amount of land it uses. Industrial agriculture puts herbicides and pesticides into our soil and water, killing micro organisms and stripping the soil of life system that creates nutrients for plants. Therefore requiring industrial fertilizers which leaches into the water table and threatens our water supply. Also industrial agriculture only uses land for one purpose at a time, therefore using more land than organic or permaculture farms which create an agriculture system of multiple layered production relationships and build biodiversity, especially for micro-organisms and insects.(note that I am not talking about industrial organic systems)
    I realize this article is not attacking the methods of organic production but it is also not taking them into account. This article is focused on biodiversity but then reduces its measure to amount of land used to construct a “simple math equation” that is just plane false and aimed at convincing the uneducated.

  10. #10 Dr Ulrich Schmutz
    September 24, 2010

    The study only looked a grain yield – a rather simplistic view.
    1. There is also straw as an important yield by-product. Straw grain rations (HI harvest index in technical terms) are different in organic versus conventional farming systems. Conventional farmers use chemicals (CCC) to artificially shorten cereals as they would fall down (lodge) under the heavy nitrogen fertilisation dosage they also get.
    In organic farming taller plants are desirable because it helps cereals to compete with beneficial weeds and other plant biodiversity on the field (remember no weed-killers allowed to eradicate all of it). Straw is also a valuable product to sell and it doesn’t matter if it contains some weeds. Therefore more yield is in straw rather then grain but lower grain yields are no problem for overall profitability.
    2. In addition, organic farmer under-sow their cereals with clover (usually white clover because grows very low). This also competes with water and nutrients to a certain extent and lowers the grain yield, however the same field once harvested has then already a good crop ready to go and use the fertilisers which in conventional production is often lost to the groundwater (pollution with nitrate and phosphate).

    In conclusion organic attempts a holistic approach producing not only grain yield rather straw, clover green manure and colourful weed plants (more then some organic farmers aim for) for butterfly and insects biodiversity. They are all plant biomass and non of it is lost to the system.
    Comparing organic and conventional only on grain yield is possible however rather simplistic as intensity also comes with other negative impacts (leaching to groundwater, pesticide accumulation, chemicals to artificially shorten plants let alone the fossil fuel energy embedded in those high inputs).

  11. #11 intercostal
    September 24, 2010

    Essentially, an experimental validation of the Borlaug hypothesis (essentially, that one of the best things you can do to help the environment is make farming more efficient, so that less land is used for it). Interesting.

    Jammin @14: Yeah, there’s enough food produced to feed the world (and our production *capacity* is even higher); world hunger isn’t caused by lack of food. Still, if we could grow the same amount of food on half the land, that would spare

    This is why I think the objection to GMO crops by some environmental groups is a bad idea. Once that becomes a mature technology, a few decades down the road … the sky’s the limit.

    Sharon @1, 7: Yeah, that’s another issue; habitats in many places don’t actually revert to their natural state due to fire suppression, invasive species etc. It would be an interesting follow-up study to determine if an organic farm has more native grassland species than abandoned land covered in Chinese tallow and the like; it might well.

  12. #12 Jammin
    September 23, 2010

    We are already producing more than enough food to feed the world – it’s just a matter of distribution. “Less efficient” farming won’t ruin that by any means, so arguing that we’d have to farm more land if everybody went organic is false, or at least misguided.

  13. #13 Hinemoana
    September 23, 2010

    @ Christopher Milton

    So, for clarity, what exactly are you suggesting when you say “we should just let nature be nature”?

  14. #14 Christopher Milton
    September 23, 2010

    “Simple math, less human numbers intruding and mutating the environment = natural diversity balance and cycles. Avoid the Stork!”

    *Yawn!* Yes, yes, pop those contraceptives! Then promptly piss them down the drain and mess up the bio-diversity of the fish in the streams a la Colorado.

    The thing that creeps me out the most is the call for genetically engineering the crops. Yes, we can help nature by messing around with it.

    Perhaps we should just let nature be nature, becuase nature takes pretty good care of itself.

  15. #15 darwinsdog
    September 22, 2010

    #4:

    The post did not seem misleading at all.

    I didn’t say that the post seemed misleading, Mike. I said that the title seemed misleading. It seemed to imply that there was something intrinsic to organic agriculture that reduced butterfly diversity when the text of the post made clear that it was anything that reduced agricultural productivity, and thereby necessitated more land being brought under production, that reduced diversity. If organic agriculture increased yield, as it sometimes can, then butterfly diversity ought to increase accordingly. The title would have been more apt had it read something like “Underproductive Farms Not Always Best for Butterflies.”

  16. #16 stripey_cat
    September 22, 2010

    My conclusion was that we need to work to increase the yields of the land, quite possibly with more intensive human labour, and also to reduce monoculture expanses that reduce habitats. In either organic or conventional systems, extensive, low-labour-input monocultures are a woefully inefficient way of getting food off acres.

  17. #17 Mary
    September 22, 2010

    Do they talk about the pesticides used on the organic farms? We know that some organic pesticides have lots of off-target effects and might actually be worse than conventional in some ways:

    http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0011250

    That would have to impact this data as well. To assume organic = pesticide-free would be incorrect.

  18. #18 Dunc
    September 22, 2010

    SSSIs are typically declared because they’re already biodiversity hotspots, or are home to some endangered species… They are, pretty much by definition, small enclaves of unique habitat, and they’re also actively managed to maintain and increase that uniqueness.

    I’d be interested to see exactly which SSSIs they were using, and the reasons they were originally declared.

  19. #19 Sharon Astyk
    September 22, 2010

    DD, I know that – my point is that at least one of the comparisons in the study seems pointless – the implication is that you’d get more butterflies if you weren’t farming the land at all. But if you don’t compare the number of butterflies *on the kind of land that follows the abandonment of farmland* then you don’t actually know if that’s true. Even scrub forests tend to support more life than farmed fields, although it isn’t necessarily clear to me that they support more *butterflies.* This strikes me as a methodological problem, if you are using butterflies to stand in for other species, or even if you aren’t.

    Sharon

  20. #20 Dunc
    September 22, 2010

    But land not used for agriculture, except in areas of natural prairie, doesn’t actually convert to grassland reserve in any natural sequence. What it converts to is forested land

    Actually, in the UK, there’s a good chance it’ll convert to housing… I’m really not convinced that using SSSIs as the baseline is valid. Even if the land in question isn’t developed or used for other purposes, it is extremely unlikely to end up as grassland SSSI.

  21. #21 megan
    September 22, 2010

    Simple math, less human numbers intruding and mutating the environment = natural diversity balance and cycles. Avoid the Stork!

  22. #22 Mike
    September 21, 2010

    The post did not seem misleading at all. If the organic industry increases, more land will be needed for farming. That will result in a decrease in biodiversity.

  23. #23 darwinsdog
    September 21, 2010

    So it isn’t organic farming techniques, per se, that result in lowered butterfly diversity, it’s anything that reduces yield resulting in more land needing to be placed under production. Hence, the title of this blog post is misleading.

    Sharon, the reason that abandoned farmland in the American Midwest doesn’t revert to grassland is because of fire suppression. Historically, prairie fires, either naturally ignited by lightning or intentionally set by settlers or Native Americans, killed saplings while leaving the roots of perennial grasses unscathed. If fires were allowed to burn abandoned farmland would indeed revert to grassland across the Midwest.

  24. #24 daedalus2u
    September 21, 2010

    I only saw the abstract, but I suspect that they used butterflies because they are easier to survey and they are using butterflies as marker species to represent the whole of biodiversity (which would be too difficult to measure).

    Completely wild land is much more diverse than any type of farmed land. Comparing diversity of organisms that can fly (birds and butterflies) doesn’t count the majority of organisms that can’t, plants, other insects, invertebrates, mammals, amphibians, etc. I appreciate that those species are not as charismatic as butterflies and birds, but they are important.

    I understand the first calculation, that if organic yields are 87% of conventional yields that conventional farming 87 hectares and 13 hectares of nature reserves yields butterfly populations equivalent to 100 hectares of organic farming.

    I am not sure I understand the second calculation. Are they saying that if organic yields are 35% of conventional, then 35 hectares of conventional farming and 65 hectares of field margins are equivalent to 100 hectares of organic farming? I think what that says is that nature reserves are five times better (13 hectares vs 65 hectares) than field margins. I think that shows just how degraded any kind of agricultural land is, even field margins.

  25. #25 Sharon Astyk
    September 21, 2010

    But land not used for agriculture, except in areas of natural prairie, doesn’t actually convert to grassland reserve in any natural sequence. What it converts to is forested land – I’m not clear on what the advantage of comparing grassland reserves is, since agricultural land is unlikely in the US, at least, to revert to such land use.

    Sharon

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