Tuesday, 24 September 2013

Let’s not blame climate change for all biogeographic change

Large numbers of biogeographical studies have demonstrated recent poleward range shifts and movement up altitudinal gradients of a variety of organisms (Bebber, Marriott, Gaston, Harris, & Scotland, 2007; Chen, Hill, Ohlemüller, Roy, & Thomas, 2011; Devictor, Julliard, Couvet, & Jiguet, 2008; Forero-Medina, Terborgh, Socolar, & Pimm, 2011; Groom, 2013; Hickling, Roy, Hill, Fox, & Thomas, 2006; Holzinger, Hülber, Camenisch, & Grabherr, 2007; Kelly & Goulden, 2008; Lenoir, Gégout, Marquet, de Ruffray, & Brisse, 2008; Leonelli, Pelfini, Morra di Cella, & Garavaglia, 2010; Parmesan & Yohe, 2003; Root et al., 2003; Smith, 1994; Sturm et al., 2001; Thomas & Lennon, 1999; Velásquez-Tibatá, Salaman, & Graham, 2012). The results of these studies are often referred to as the fingerprint of climate change on biodiversity. However, there are many manmade and environmental factors that have undergone far larger recent change than climate. These changes, either individually or in combination, can also explain these range shifts and we should not be so quick to implicate the climate.

Among the environmental factors that have changed significantly in the last 50-100 years are atmospheric nitrogen deposition; changes in grazing patterns, particularly in mountains; pollution changes, particularly acid rain and salt spreading; a doubling of the CO2 concentration of the atmosphere; a multifold increase in the distances and volume of the international horticultural trade; changes in land management; extensive greenhouse horticulture; heat islands caused by urbanization. In comparison to these factors, the climate has changed very little in the same period. All of these factors have been shown to affect organisms directly and many are known drivers of migration and/or extinction. Yet, papers continue to be published that stress the climate as an explanation.

Mankind is by far the most important disperser of plants and probably also animals and microorganisms (Mack & Lonsdale, 2001). Manmade habitat disturbance impinges on practically all ecosystems of the earth. Even in the Artic, which has experienced the greatest climate change so far, acid rain and atmospheric nitrogen deposition have a significant impact on the vegetation (Bobbink et al., 2010; Sarah J. Woodin, 1997). Manmade disturbance is often portrayed as a destructive influence on natural habitats but in reality its influence is more often for change rather than destruction.

In my own research on the native plants of Great Britain, northerly range shifts could be seen in many species since 1978 (Groom, 2013). However, these changes cannot be explained by the plant’s preferred climate envelope, but are more easily explained by other factors such as habitat change and pollution.

We should be careful about jumping to conclusions about the causes of biogeographic range shifts. It makes sense to look for explanations of change among the factors that have changed the most and only once these factors have been eliminated should one start looking for explanations elsewhere. While climate change will eventually have a large impact on the distribution of organisms, the focus on it as an explanation for all range shifts is obscuring other possible explanations and distorting our view of the changes in biogeography.


Bebber, D. P., Marriott, F. H. C., Gaston, K. J., Harris, S. A., & Scotland, R. W. (2007). Predicting unknown species numbers using discovery curves. Proceedings. Biological sciences / The Royal Society, 274(1618), 1651–8. doi:10.1098/rspb.2007.0464
Bobbink, R., Hicks, K., Galloway, J., Spranger, T., Alkemade, R., Ashmore, M., Bustamante, M., et al. (2010). Global assessment of nitrogen deposition effects on terrestrial plant diversity: a synthesis. Ecological Applications, 20(1), 30–59. doi:10.1890/08-1140.1
Chen, I., Hill, J. K., Ohlemüller, R., Roy, D. B., & Thomas, C. D. (2011). Rapid range shifts of species associated with high levels of climate warming. Science (New York, N.Y.), 333(6045), 1024–6. doi:10.1126/science.1206432
Devictor, V., Julliard, R., Couvet, D., & Jiguet, F. (2008). Birds are tracking climate warming, but not fast enough. Proceedings. Biological sciences / The Royal Society, 275(1652), 2743–8. doi:10.1098/rspb.2008.0878
Forero-Medina, G., Terborgh, J., Socolar, S. J., & Pimm, S. L. (2011). Elevational ranges of birds on a tropical montane gradient lag behind warming temperatures. PloS one, 6(12), e28535. doi:10.1371/journal.pone.0028535
Groom, Q. J. (2013). Some poleward movement of British native vascular plants is occurring, but the fingerprint of climate change is not evident. PeerJ, 1, e77. doi:10.7717/peerj.77
Hickling, R., Roy, D. B., Hill, J. K., Fox, R., & Thomas. (2006). The distributions of a wide range of taxonomic groups are expanding polewards. Global Change Biology, 12(3), 450–455. doi:10.1111/j.1365-2486.2006.01116.x
Holzinger, B., Hülber, K., Camenisch, M., & Grabherr, G. (2007). Changes in plant species richness over the last century in the eastern Swiss Alps: elevational gradient, bedrock effects and migration rates. Plant Ecology, 195(2), 179–196. doi:10.1007/s11258-007-9314-9
Kelly, A. E., & Goulden, M. L. (2008). Rapid shifts in plant distribution with recent climate change. Proceedings of the National Academy of Sciences of the United States of America, 105(33), 11823–6. doi:10.1073/pnas.0802891105
Lenoir, J., Gégout, J. C., Marquet, P. A., De Ruffray, P., & Brisse, H. (2008). A significant upward shift in plant species optimum elevation during the 20th century. Science (New York, N.Y.), 320(5884), 1768–71. doi:10.1126/science.1156831
Leonelli, G., Pelfini, M., Morra di Cella, U., & Garavaglia, V. (2010). Climate Warming and the Recent Treeline Shift in the European Alps: The Role of Geomorphological Factors in High-Altitude Sites. AMBIO, 40(3), 264–273. doi:10.1007/s13280-010-0096-2
Mack, R. N., & Lonsdale, W. M. (2001). Humans as Global Plant Dispersers: Getting More Than We Bargained For. BioScience, 51(2), 95. doi:10.1641/0006-3568(2001)051[0095:HAGPDG]2.0.CO;2
Parmesan, C., & Yohe, G. (2003). A globally coherent fingerprint of climate change impacts across natural systems. Nature, 421(6918), 37–42. doi:10.1038/nature01286
Root, T. L., Price, J. T., Hall, K. R., Schneider, S. H., Rosenzweig, C., & Pounds, J. A. (2003). Fingerprints of global warming on wild animals and plants. Nature, 421(6918), 57–60. doi:10.1038/nature01333
Sarah J. Woodin. (1997). Effects of acid deposition on arctic vegetation. In S. J. Woodin & M. Marquiss (Eds.), Ecology of Arctic Environments 13th Special Symposium of the British Ecological Society (p. 292). Cambridge University Press.
Smith, R. (1994). Vascular plants as bioindicators of regional warming in Antarctica. Oecologia, (January), 322–328. Retrieved from http://link.springer.com/article/10.1007/BF00627745
Sturm, M., Racine, C., Tape, K., Cronin, T. W., Caldwell, R. L., & Marshall, J. (2001). Increasing shrub abundance in the Arctic. Nature, 411(May), 546.
Thomas, C., & Lennon, J. (1999). Birds extend their ranges northwards. Nature, 399(May), 6505. Retrieved from http://docencia.izt.uam.mx/hcg/cursoact_CC/material_adicional/399213a0.pdf
Velásquez-Tibatá, J., Salaman, P., & Graham, C. H. (2012). Effects of climate change on species distribution, community structure, and conservation of birds in protected areas in Colombia. Regional Environmental Change, 13(2), 235–248. doi:10.1007/s10113-012-0329-y
Update 13 Aug. 2014: An example of a publication implicating grazing changes in tree line movements Aakala, T, Hari P, Dengel S, Newberry SL, Mizunuma T, Grace J (2014) prominent stepwise advance of the tree line in North-East Finland DOI: 10.1111/1365-2745.12308

This work by Quentin Groom is licensed under a Creative Commons Attribution 3.0 Unported License.

Wednesday, 11 September 2013

Fueling botanical recording in England, Ireland, Scotland and Wales

The Botanical Society's Recorder’s Conference is over for 2013, but this is not an end, just a pit stop in the collection of botanical data. Now that the field season draws to a close, this event is an opportunity for the botanists of England, Ireland, Scotland and Wales to share knowledge, argue about policies, meet friends and make new ones.
At this year’s conference, some of the presentations were the taxonomy of Dactylorhiza and Orchis; on escaped alien ferns; on willows and poplars; on rare plants of Somerset; on the flora of Tristan da Cunha and on errors in botanical recording.

Britain and Ireland’s field botanists are a well-motivated, confident group whose work means that these are probably the best surveyed countries in the world and they do this largely out of their own pockets.

Now that I am botanically recharged I am confident in the continued progress the Botanical Society is making towards the study of the north-western European flora. We have many challenges ahead of us . We need to look forward to the next atlas of the flora; to the challenges of conservation; to monitoring change and to recruiting and training the next generation of field botanists. However, it is obvious at the conference that we have the people who can do the job and the enthusiasm to fuel it.
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This work by Quentin Groom is licensed under a Creative Commons Attribution 3.0 Unported License.

Sunday, 1 September 2013

Taxonomy can't just be a glorified hobby

One of my contributions to the pro-iBiosphere project is a report on the use of digital technology among taxonomists (Groom et al., 2013). In the preparation of this report I got to talk to many taxonomists about their work and their expectations for the future. I don’t think it is an exaggeration to say that all taxonomists are passionate and dedicated to what they do. Indeed, unlike most professions, if they weren't paid to do it they would do it for free. Many retired taxonomists continue their work unpaid and many employed taxonomists self-fund their own research.

Isn't this fantastic? We are told that there are literally millions of undescribed organisms and we have an enthusiastic group of people who don’t even need paying to do the work. Well of course there is a catch, people who are under-resourced, under-appreciated and expected to work based on their passion for the subject will do the work exactly in the way they want to. So it is not unusual  for a taxonomist to publish their magnum opus in an obscure publication, with a print run of less than 100 with no digitally accessible version. Indeed, it is a particular quirk of the international codes for biological nomenclature that anyone can publish names for organisms, anywhere and without peer review. This certainly contributes to a general disrespect among scientists for taxonomy.

Yet, with no funding there is no requirement on taxonomists to work on economically important species; nor is there a requirement to publish taxonomy digitally and make it accessible to the people who need it, in language they can read. Furthermore, taxonomists have no incentive to maintain a stable or complete taxonomy free from ambiguity.

Moreover, codes of biological nomenclature are decided upon democratically within the taxonomic community, but without consultation with the users of taxonomy. In them are many rules to ensure that taxonomists get credit for describing new taxa, but few to ensure that taxonomic names act as a unique stable identifier of taxa in a digital world.

If the beneficiaries of taxonomy want a stable and a usable system of names for the life on earth then these users will have to start demanding this and paying for it. And if taxonomists want funding for their work and respect for their profession they have to start asking what the users want and start providing it.

Groom, Q., Agosti, D., Güntsch, A., Hovenkamp, P., Eralt, E., Mietchen, D., Paton, A. & Sierra, S. (2013) The Use of e-Tools among Producers of Taxonomic Knowledge. Figshare. http://dx.doi.org/10.6084/m9.figshare.785738 Retrieved 09:51, Sep 01, 2013 (GMT)

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This work by Quentin Groom is licensed under a Creative Commons Attribution 3.0 Unported License.