Requiem redux - it’s the ecology, stupid
Walker Wood is glowing with spring colours of white and blue. Wild garlic gets malodourous as it goes over, so not yet, but the honey fragrance of bluebells is heady. While we are there for the wildflowers, it is bird song that completes the sensory picture. We listen out amongst the trilling for the tree creeper (Certhia familiaris) nuthatch (Sitta europaea) and jay (Garrulus glandarius) birds strongly associated with woodland. The rasping, screaming call of the jay is the easiest to identify as it flies agitatedly between trees (1). Of the two smaller birds, the nuthatch’s call is the stronger (2) the blue-grey wings and chestnut brown breast of this plump bird just larger than a robin can also be recognised flying between trees. The call of the tree creeper is the softest ("tsee-tsee-tsi-tsi-si-si-si-si-sisisisisi") (3) and it is a difficult bird to spot, unless you get lucky.
We were able to watch a couple of tree creepers earlier in February this year when we revisited Sneaton Forest. We were looking across at some alders, while sitting on the bank of Parsley Beck, when we saw these small birds creeping up the trunks, their long claws good for gripping on to the raggedy, fissured bark. This is their foraging behaviour, their slim, down-curved beaks exploring and reaching under the tree bark for invertebrates like insects and spiders. Their mottled black, brown, tan and white plumage is a perfect camouflage up against the patterned bark, their stiff tail feathers used as a support while climbing. Once they had reached the top of a tree, they swooped down to begin foraging at the base of the next tree.
An indicator species for woodland ecosystems
Tree-creepers are sedentary (non-migratory) tending to stay localised all year (4,5). Their breeding season occurs between March and late June when they make camouflaged nests out of twigs, vegetation, bark, fibres, leaves, mosses, and feathers, in tree crevices and behind pieces of loose bark. Since they rely on trees that have some old-growth characteristics - the cracks and crevices in the bark for foraging, roosting and nesting - they tend to be in woodlands that have densities of large, mature trees. The nuthatch is sedentary and also forages for invertebrates, mainly caterpillars and beetles, which its plucks from tree trunks and branches (6,7). In a reverse of tree creepers, nuthatches often descend trunks head first when searching for food. Like the tree creeper, the nut hatch inhabits mature woodlands with large old trees, and with a well-developed canopy providing extensive foraging areas. They nest in tree holes, usually old woodpecker nests, but sometimes also in natural cavities.
Considering their similar life history, it’s not surprising that both the tree creeper and nuthatch occupy the same trophic niche of Invertivore, their foraging niche being classified as Invertivore bark ((8-11) and see a schematic of avian trophic niches (Fig. a) and foraging niches (Fig. b) in (12)). You won’t get this sort of ecological taxonomy in the species descriptions of voluntary conservation organisations in Britain like the RSPB, British Trust for Ornithology or Woodland Trust. They cater for bird spotters rather than those who wish to understand the ecological significance of a species. Other than turning to the literature, which is often behind a paywall, it took the effort of Avibase, hosted by Birds Canada, to add life history data to the extensive information system it has about all the birds of the world (13). Armed with this, it becomes possible to combine observations of bird species in the natural world with the ecology they reveal.
It struck me, as we watched the tree creepers in Sneaton Forest, that they may be an indicator species in Britain for the status of woodland ecosystems and their trophic diversity – they would be an ecological indicator of trees exhibiting features of maturity and aging, as well as for the presence of other species due to increasing senescence giving rise to a multiplicity of niches. I had come across this before in relation to woodpeckers in mainland Europe when writing a book chapter about the Ecological Values of Europe’s Wilderness (14). In exploring the dependency of European species on wilderness qualities, I made a distinction between species whose survival had a strong linkage to specific natural process, while others are only able to survive in areas with sufficient space and with access to certain trophic functions of wild nature. Large carnivores in need of areas with sufficient home range were examples of the latter.
Examples of the first group were those species dependant on the dead and decaying wood that is characteristic of natural, old growth forests, such as lichens, fungi and invertebrates, as well as the forest specialist woodpeckers that prey on those invertebrates and which, along with some owls and bats, find nesting homes in the mould that accumulates in bark bags that arise when dead bark is partially lifted on old trees. Various species of beetle are hosted in the bark bags and are foraged by insectivorous woodpecker species, but some woodpeckers also hammer on dead trees to dig out wood boring beetles. As I noted, the dependence of three woodpecker species – the middle spotted woodpecker (Dendrocopos medius) the long-beaked white-backed woodpecker (Dendrocopos leucotos) and the three-toed woodpecker (Picoides tridactylus) on large areas of long-lived forest with the characteristic properties of natural processes, identified them as indicator species for other species associated with unmanaged forests rich in older trees and dead wood, such as the invertebrates, fungi, and assemblages of other resident forest bird species.
I never considered back then that the ecological reality of our three native woodpeckers - great spotted woodpecker (Dendrocopos major) lesser spotted woodpecker (Dendrocopus minor) and green woodpecker (Picus viridis) – would stack up against the more numerous, larger and more diverse woodpecker species in mainland Europe and their trophic ecology: as well as our natives, and the three species noted above, mainland Europe has a further three woodpecker species in the grey-headed (Picus canus) black (Dryocopus martius) and the Syrian woodpecker (Dendrocopos syriacus). The sounds of woodpeckers are not entirely uncommon in the woods I walk, from the drumming of the great spotted woodpecker (15) and the distinctive yaffle call of the green woodpecker (16) but I never seem to get the opportunity to observe them for any length of time. Perhaps if I did, then I would be encouraged to reconsider exploring their ecological niche.
It took some time for us to overcome our dismay at the devastation we had seen last year in Sneaton Forest wrought by the incursion of sheep – the degraded ground vegetation and the ubiquity of sheep excrement and snagged wool – before we would consider returning there (17). We were glad when we did, not only for the prolonged observation of the tree creepers, but to see that breaks in the boundary fence had been mended and, bar the odd wool snag that I plucked off and threw to the ground to facilitate its decomposition, there was little evidence left that sheep had been there. It was a revelation how wild nature had absorbed its wounds in the intervening months. It took away some of the hurt I had felt when I had reluctantly come to the conclusion that I could no longer bear the disappointment; that my advocacy for a self-willed land had become a complete irrelevance. The dangers I warned of then, the perverse loss of focus on what really matters for wild nature, have continued to burgeon (i.e. 18-24). Just more fodder for the gullible, although I try to avoid being aware of it. I did receive a citation in peer-reviewed literature for that requiem article of disappointment. This is a rare event for my personal advocacy, but it was only referenced as an objection to the premise of the publication that anyway confirms the fear I had of where the populist agenda of anthropizing ecological restoration was heading (25).
I said then that I needed space to think about what my aims may be for the future. It hasn’t worked, but what has is the continuing rhythm of seeking out wild nature – we never stop looking and learning. There have been some highlights. After a hiatus of a couple of years, we got to walk the low tide rock platforms in Northumberland again last November, searching for elusive sea squirts that we find difficult to come across on this coast. We are absorbed by low tide marine trophic ecology, sea squirts being an herbivorous animal that is both predator in filtering phytoplankton and algae, and prey in being eaten by cowries, a sea snail (Trivia monarcha). Finding empty cowrie shells washed up over the years along this coast tends to confirm that there should be sea squirts (26,27). From experience, we know where to look, the vertical rock faces in shade but uncluttered with sea weed that are at the outer edge of sea retreat that is exposed during the exceptional lows of Spring tides. This is the infralittoral fringe, the zone beyond the low-tide mark being the sublittoral. Sea squirts can’t afford to dry out when uncovered at low tide, unlike wracks, the brown fucoid sea weeds found higher up the shore. Thus sea squirts colonise shade and are closer to the low water mark so that their time out of water is the shortest. Being this far out in the intertidal zone also means being covered by a greater depth of water at high tide, and which reduces the amount of light reaching this depth, and thus the types of sea weeds that can thrive there.
We had found the orange sea squirt Botrylloides leachii a few years back in an unexpected location (27) but it is the star ascidians that we quest for. So on a mostly sunny but windy Saturday morning in early November, we stepped out on the E side of Braidcarr Rocks below Seahouses with the prospect of one of the better low tides of the year (0.3m). We walked carefully over rock terrace exhibiting the patterns of seaweed zonation determined by relative depth at high tide and wave exposure. It is covered with wrack seaweeds at first that give way further out to sparser cover with smaller seaweeds such as common green branched weed (Cladophora rupestris) and pepper dulse (Osmundea pinnatifida) before reaching areas overlaid with thongweed (Himanthalia elongata) and then the kelps dangling at the infralittoral edge of the rock terrace. Nearing the edge, we headed for any large, accessible gullies or edges in the rock terrace that have a vertical rock face shaded from the sun. We soon came across pale-yellow herbivorous breadcrumb sponges (Halichondrea panicea) on edges and gully walls. It got interesting when we found largish areas of the reddish-brown baked bean sea squirt (Dendrodoa grossularia) with its two closed-up siphons evident as small bumps on the bean. Then we came across small colonies of a beautiful star ascidian (Botryllus schlosseri) the 6-9 pale cream, tear-shaped zooids arranged in a star pattern around a central opening, these stars filling a light-orange gelatinous tunic coating.
A couple of days later, we were watching the waves break at low tide on Harkess Rocks just up from Bamburgh Castle, and admiring the eider ducks (Somateria mollissima) snoozing on the exposed rocks. We have done this many times, but there was one shady rock face there that we realised we hadn’t explored. In a pool at its base were a row of open dahlia anemones (Urticina felina) with an array of colour bandings on the tentacles. Hanging upside down above those was something odd that we did not recognise, but later identified as a closed-up plumose anemone (Metridium dianthus). Looking unfortunately like a long pale-pink smooth tube when closed, it has numerous fine tentacles that form a plume at the end of the tube when the anemone opens under water. It must look astonishing.
It is this repeated exploration of the same places that eventually yields up the most exciting observations, as you become more experienced at where to look. This is also true for the N Yorkshire coast where we have at last come across a couple of squirts on the low tide rock terraces just to the SE of Whitby: baked bean squirt near Black Nab (28) and Botrylloides leachii (29) near Saltwick Nab. There have also been many herbivorous sea hares (Aplysia punctata)(30) this Spring on the lower, coral weed (Corallina officinalis) covered terraces at Saltwick Nab after having migrated inshore to breed. They feed on seaweeds, taking on the colour of what they eat. We also found a few sea lemons (Doris pseudoargus) tucked away under boulders or in crevices, and where you would expect to find them as these carnivorous sea slugs feed on breadcrumb sponges that also prefer these shady niches. We get to watch purple sandpipers (Calidris maritima) there, a winter visitor from arctic islands and the sub-arctic coasts of Scandinavia, which feed along the water’s edge of rocky, sea-weedy shores, picking small sea snails, small shrimp-like crustaceans and segmented sea worms (31-33). They never seem to mind us watching, and will just displace a short distance while chattering (34) if we have moved too near. Although they are waders, we have seen them swim across small pools when they are two deep to walk, a surprising achievement since they only have clawed feet (33).
An instinct for enquiry
My understanding of ecology is self-schooled and immensely aided by this instinct for enquiry that likely stemmed from the way I was taught biology in secondary school during the 1960s. That decade had started with a concern for a renewal of the science curriculum and for a wider study of imaginative ways of teaching scientific subjects. In response, a charitable trust, the Nuffield Foundation, set up a science teaching project, the first outcome being a course for biology up to the age of 16 that was supported with textbooks and a guide to help teachers present science in a lively, exciting and intelligible way – it had an emphasis on practical work and problem-solving activities (35). Amongst the aims of its approach were to develop and encourage an attitude of curiosity and enquiry, and to encourage a respect and feeling for all living things. It would teach the art of planning scientific investigations, the formulation of questions, and the design of experiments, as well as develop a critical approach to evidence. Reading about it now, it was quite challenging for teachers to deliver the course, which probably contributed to its low take up by schools – the proportion of school students taking the Nuffield biology exams got no higher than 7.1% - but the additional expense of delivering the course along with the cost of the text books and teachers guide also contributed (36).
Given the laudable aims of the Nuffield approach and the effect it had on me, you can imagine my scepticism when I came across proposals for a new course on natural history for secondary school children (37). I couldn’t see the need for it, a justification being that there was a gap in natural history content in education when children reached secondary school, and a suggestion that it would equip the next generation with the skills to look after the natural world (38,39). By calling it natural history it continues to de-emphasise the intrinsic value and right to existence of wild nature, delivering instead some romantic notion, of a succession of Gilbert White clones as observers of culturally dominated landscapes – his “parochial history” (40). As evidence of this, one amongst many jarring potential content areas in the curriculum given in a consultation was Theme 4: Human impact on the world - "Introduction of grazing to encourage biodiversity (e.g. in woodland)" (see pg. 17 in (41)). This would seem to be setting schoolchildren up to be indoctrinated in the dogma of the mainstream conservation industry. According to the exam board OCR, the Department for Education (DfE) is taking the proposal forward and will launch its own consultation along with the Office of Qualifications and Examinations Regulation (Ofqual) (37). The latter two will decide subject content and requirements/guidelines before OCR writes a specification for the exam curriculum and sample assessment material that Ofqual then has to accredit.
There was nothing about that consultation in the DfE press release that splashed the new natural history course as part of the Sustainability and Climate Change Strategy (42). I guess we will have to look out for it and encourage people to respond, because I believe there is no need for a natural history course. Nature protection is better learnt within a science context. If biology courses are deficient in achieving this, then there must be a greater determination to more effectively revise all biology courses in the mode of the Nuffield approach, rather than what happened in the 1960s when it took the voluntary sector to fill that vacuum but at an additional cost to schools. In addition, cross-curricula links should be made with nature protection and the three sciences, mathematics and geography. Furthermore, if we are truly going to lift our schoolchildren out of the straitjacket of nature studies, then they have to be able to look past the cultural domination of land and nature and foresee a future where the intrinsic ecology of the natural world is expressed here again.
It’s the ecology, stupid
It’s a question of ecological literacy, of ecological concepts and principles learnt experientially through scientific inquiry and ecological thinking. (43). I find it staggering that a journal article from 2014 that bemoaned the decreasing presence of natural history in science and society did not once mention ecology (44) and so you can see what we are up against. As with many things to do with wild nature, we can learn from America. Facing similar concerns about the need to reform biology teaching in the late 1950s, the National Science Foundation funded the American Institute of Biological Sciences (AIBS) to review the status of biology textbooks and produce new, updated curriculum materials (see Section V in (45)). The Biological Sciences Curriculum Study (BSCS) was established by AIBS, and which produced a series of biology textbooks, each taking a different approach: that taking an ecological approach to learning and teaching biology was dubbed the Green Version; an approach at the molecular level was the Blue Version; and an approach at the cellular level was the Yellow Version. In a parallel to the Nuffield approach, it was learning science through the perspectives and methods of inquiry, with an accompanying teacher’s handbook that had a series of Invitations to Inquiry (see section II in (45)). These were activities that schoolchildren undertook to make discoveries of their own, be questioning rather than being fed information.
One Invitation to Inquiry was on Predator-Prey and Natural Populations where schoolchildren were given the situation of a biologist studying populations of small rodents and owls in a particular location to find out what factors tended to control the size of the populations (see pg. 90 in (45)). As variables, the schoolchildren are told that the rodent population declined during the study period because of a virulent disease, but that the adult owl population was unchanged. However, the number of newly hatched owls was far less than in previous counts. The pupils are then asked to consider various factors to explain the results, such as food supply, increased infant mortality rate or to a decreased birth rate and how you would distinguish between the two, and then with other observations thrown in, such as change in mating behaviour, and whether the biologist was able to draw robust conclusions from the data.
Staying with America, I noted back in 2006 that twelfth grade students at Berkeley High School in California could take a course in ecoliteracy that covered the principles of ecology; systems thinking; and the development and practice of ecological values (46). One of the course units was entitled The Experience of Nature and required students to spend at least five days backpacking in a wilderness area as a means of developing a "deeper relationship with the earth along with enhancing teamwork, cooperation, group cohesion, and personal motivation”. As you might expect, there is extensive cross-curricula resources available in America for wilderness studies and, if used here, they would prepare our schoolchildren to envisage and make happen that future where the intrinsic ecology of the natural world is expressed here again. The studies for schoolchildren aged between 14 and 18 (9-12 Grade) are built around lessons and practical tasks on such topics as working out carrying capacities for a group of large carnivore species given their home ranges, and then using a map to find a suitable area sufficiently large enough to accommodate them (see pg. 435 onwards in (47)). Another is working through a handout on the approach to a regional reserve network (criteria for cores, buffers, corridors) and then mapping one for their region (see pg. 139 onwards in (47)).
This is not some idiotic fantasy. I have written before about the voluntary westward expansion of wolves across mainland Europe so that there is now a presence in every country (48). As I noted, this is one of the greatest natural experiments in reinstatement of trophic ecology, and that we should be learning from it. We should be using every piece of scientific evidence that has arisen in this colonisation of modified landscapes to predict how wolves would use the landscapes of Britain, where they would choose to reside, and what routes they would take to disperse. Wolves are metaphysically knocking on our door – a report three days ago confirmed that a wolf had turned up after a century of absence in Finistère in Brittany, the westernmost department of France (49). However, if you wanted to ease into this exploration of trophic reinstatement, then multiple species interaction, habitat selection, differential predation, and non-native species, can all be explored and learned from activities based around the spatial distribution and trophic interaction between pine marten (Martes martes) red squirrels (Sciurus vulgaris) and grey squirrels (Sciurus carolinensis)(50).
I always find someone who has earlier
articulated what makes good sense now, but it is frustrating when the
progressive steps that the idea represented get
lost. Eric Caulton did so over 50 years ago when he gave a paper during a
symposium on Introducing Biology to the School
that was subsequently published in 1970 in the Journal of Biological
Education. The article was entitled An Ecological Approach to Biology
and in it Caulton explained what ecology is, and why and how it should be
taught (51). He recommended the self-discovery that would come through regular
field visits to the same place,
at least once per season, and stressed that field and laboratory work be
correlated to emphasize the link between the two. He commended both the
Nuffield and BSCS schemes for biology. Here is what he finished on:
Mark Fisher 8 May 2022
(1) XC683600 · Eurasian Jay · Garrulus glandarius, xeno-canto
(2) ML310394301 - Eurasian Treecreeper (Certhia familiaris) Macaulay Library
(3) XC72675 · Eurasian Treecreeper · Certhia familiaris, xeno canto
(4) Certhia familiaris -- Linnaeus, 1758, BirdLife International
(5) Certhia familiaris : Eurasian tree-creeper, Animal Diversity Web
(6) Eurasian Nuthatch (Sitta europaea) Birdlife International
(7) Nuthatch (Sitta europaea) Woodland Trust
(8) Life History, Eurasian Tree-Creeper (Certhia familiaris) Linnaeus, 1758, Avibase
(9) Life History, Wood or Siberian Nuthatch Sitta europaea) Linnaeus, 1758, Avibase
(10) Pigot, A.L., Sheard, C., Miller, E.T., Bregman, T.P., Freeman, B.G., Roll, U., Seddon, N., Trisos, C.H., Weeks, B.C. and Tobias, J.A. (2020) Macroevolutionary convergence connects morphological form to ecological function in birds. Nature Ecology & Evolution, 4(2): 230-239
(11) Tobias, J. A., and others (2022). AVONET: morphological, ecological and geographical data for all birds. Ecology Letters, 25(3): 581-597
(12) Avian trophic niches and foraging niches.
(13) Welcome to Avibase, Avibase - The World Bird Database
(14) Fisher, M. (2016) Ecological Values of Europe’s Wilderness. In Bastmeijer, K. (Ed.) Wilderness protection in Europe: the role of international, European and national law. Cambridge University Press
(15) XC700702 · Great Spotted Woodpecker · Dendrocopos major major
(16) XC70716 · European Green Woodpecker · Picus viridis
(17) Requiem for rewilding, Self-willed land July 2021
(18) Martin, A., Fischer, A., McMorran, R., & Smith, M. (2021). Taming rewilding-from the ecological to the social: How rewilding discourse in Scotland has come to include people. Land Use Policy, 111, 105677.
(19) Thomas, V. (2021). Domesticating Rewilding: Interpreting Rewilding in England’s Green and Pleasant Land. Environmental Values
(20) Jepson, P. R. (2022). To capitalise on the Decade of Ecosystem Restoration, we need institutional redesign to empower advances in restoration ecology and rewilding. People and Nature
(21) Trouwborst, A., & Svenning, J. C. (2022) Megafauna restoration as a legal obligation: International biodiversity law and the rehabilitation of large mammals in Europe. Review of European, Comparative & International Environmental Law
(22) Teanby, A., Biddell, M. & Barringer, H. (2022) Spotlight: The business of rewilding. Savills Research 5 JANUARY 2022
(23) to Bühne, H. S., Ross, B., Sandom, C. J., & Pettorelli, N. (2022). Monitoring rewilding from space: The Knepp estate as a case study. Journal of Environmental Management, 312: 114867
(24) Thomas, V. (2022) The Biopolitics of (English) Rewilding. Conservation and Society
(25) Corson, M. S., Mondiere, A., Morel, L., & van der Werf, H. (2022). Beyond agroecology: Agricultural rewilding, a prospect for livestock systems. Agricultural Systems. 199: 103410
(26) Discriminating between the wild and not wild, Self-willed land August 2017
(27) Species distribution mapping and its insights on the self-assembly of wild nature, Self-willed land October 2017
(28) Mark Fisher (@markwilderness) Twitter 18 April 2022
(29) Mark Fisher (@markwilderness) Twitter 1 May 2022
(30) Mark Fisher (@markwilderness) Twitter 4 April 2022
(31) Purple Sandpiper (Calidris maritima) Birdlife International
(32) Purple Sandpiper . Calidris maritima, Life history data, Avibase
(33) Calidris maritima . purple sandpiper, Animal Diversity Web
(34) XC423507 Purple Sandpiper Calidris maritima, Xeno Canto
(35) Nuffield Biology, STEM Learning
(36) Gould, C. D. (1983). The impact of Nuffield 0-level Biology—an agent of change in biology teaching? Journal of Biological Education, 17(3), 201-204
(37) GCSE Natural History, OCR
(38) Could you spot a grampy pig? Schools could soon offer natural history GCSE, Phoebe Weston, Guardian 21 August 2021
(39) GCSE Natural History FAQs, OCR
(40) Ecological flow, nature protection, and the wolf, 5 July 2020
(41) Consultation regarding a potential GCSE in Natural History: Early findings 27th July 2020, OCR
(42) UK to lead the way in climate and sustainability education, DfE Press Release 21 April 2022
(43) McBride, B. B., Brewer, C. A., Berkowitz, A. R., & Borrie, W. T. (2013). Environmental literacy, ecological literacy, ecoliteracy: what do we mean and how did we get here? Ecosphere 4: art67
(44) Tewksbury, J.J., Anderson, J.G., Bakker, J.D., Billo, T.J., Dunwiddie, P.W., Groom, M.J., Hampton, S.E., Herman, S.G., Levey, D.J., Machnicki, N.J. and Del Rio, C.M., 2014. Natural history's place in science and society. BioScience, 64(4): 300-310
(45) Biology Teacher's Handbook, 4th ed. BSCS & NSTA Press 2009
(46) The getting of ecoliteracy, Self-willed land December 2006
(47) The Wilderness and Land Ethic Curriculum, 9-12 Grade. Arthur Carhart National Wilderness Training Center 1999
(48) The separation between wolves and humans in modified landscapes, Self-willed land March 2020
(49) Observation d’un Loup dans le Finistère, Groupe Loup de Bretagne 5 mai 2022
(50) Twining, J.P., Montgomery, W.I. & Tosh, D.G. (2020) Declining invasive grey squirrel populations may persist in refugia as native predator recovery reverses squirrel species replacement. Journal of Applied Ecology 58 (2): 248-260
(51) Caulton, E. (1970). An ecological approach to biology. Journal of Biological Education, 4(1): 1-10. Reprinted from pg. 173 in - New trends in biology teaching Vol. III, UNESCO 1971