Ephemerum Cohaerens

Article

Ephemerum cohaerens,

an exquisite survivor of v E. cohaerens. Norbert Schnyder (Institut für Systematische Botanik, functional alluvial habitats Universität Zürich) here is a significant number of bryo- Many bryophytes are now so familiar to fact almost never observed in such a situation on the revised UK Red List (Hodgetts, 2011) phytes that are most often found in us in man-made habitats that it is often (Greven 2011). One could wonder where and in other countries’ Red Data Books. This artificial habitats. In the 20th cen- Rhynchostegium rotundifolium was growing species has a wide but discontinuous range in the difficult to understand what their natural tury, rapid urbanization and exploita- before human settlement. Holarctic, being mentioned in Eastern North tion of natural resources throughout habitat would be without human The study of the original habitats of America (Bryan & Anderson 1957; Crum & TWestern Europe have profoundly altered the synanthropic bryophytes (ecologically associ- Anderson 1981; Bryan 2005), in Asia (China intervention. Vincent Hugonnot and natural habitats of mosses and liverworts. ated with humans) can be a stimulating research and Japan; Bryan 2005) and Europe, where it Recording of bryophytes in cities and artificial colleagues takes a look at one such area. A population growing in an artificial extends from Spain to The Netherlands, and habitats has increased dramatically in the last species, Ephemerum cohaerens, habitat cannot be considered precisely equivalent from the United Kingdom to Poland. A recent few decades, and has significantly improved our with a natural one, and it is a well-established French distribution map showed a great scarcity familiar (although rare) to French and knowledge of the artificial ecology of bryophytes. fact that populations are liable to genetic of the species in France (Hugonnot et al., 2005). Tortula muralis is ubiquitous and abundant British bryologists from the inundation modification following colonization events. on concrete, mortared walls and roof tiles but zone of artificial reservoirs. From a management perspective, a good under- The inundation zone of reservoirs as a habitat is often present in only modest quantity on standing of natural habitats may be crucial for an for E. cohaerens calcareous rock outcrops in France or other crinita is almost always found on mortared accurate conservation action plan. The inundation zone of reservoirs provides parts of Europe. Riccia crystallina is found on walls in churchyards in southern France. Many Ephemerum cohaerens (Hedw.) Hampe is important habitats for mosses (Atherton et al., compacted, fine-textured substrates in gardens, bryophytes are adapted to arable land and some typically linked with artificial reservoirs in France 2010). Alternative flooding and exposure are but also in the inundation zone of natural ponds. particular species are difficult to spot outside this and in the UK, so its natural habitat is somewhat characteristic of the margins of water bodies In cities, Syntrichia papillosa is observed growing anthropogenic habitat (for example Dicranella obscure. We focused on this species because of its (Ellenberg, 1988; Rodwell, 2000), whilst on concrete, but it is a typical epiphyte of Quercus staphylina and Didymodon tomaculosus). In rarity worldwide and because it could be a useful open and moist, fine-textured substrates are in natural Mediterranean areas. Pseudocalliergon southern France, Leptophascum leptophyllum is tool in a conservation context. most characteristic. E. cohaerens shows special lycopodioides is often found in oligotrophic only observed along heavily disturbed paths in adaptations to this peculiar habitat, such as fens, but also in China clay quarries in France. or near urban areas, whilst its British occurrences The distribution ofE. cohaerens rhizoidal tubers (Pressel et al., 2005), fast Leptodictyum riparium is found growing at the are in arable fields in the south. Rhynchostegium Following the recent taxonomic revision of growth and abundant production of large base of deciduous shrubs in alluvial forests and rotundifolium is a specialist of castle walls and Holyoak (2010), six species of the genus spores (50–90 µm) that enable it to cope with also in greenhouses and on sloping tarmac roads. is never found in natural biotopes in France, Ephemerum are known to occur in Europe. specific seasonal constraints (alternating cycles For such species, it is not difficult to explain whereas its two British populations are both E. cohaerens is one of the rarest species and of waterlogging and drying). As it has been occurrences in artificial habitats as chance adjacent to lanes. In these cases, the original and is included in the Red Data List of European demonstrated that the spore bank is of utmost colonization of secondary ecological niches. natural habitat can be rather difficult to trace. Bryophytes with the status ‘Vulnerable’ (ECCB relevance in the strategy of Physcomitrium On the other hand, some species have artificial It is not difficult to see G. crinita as a typical 1995). It is also listed in the British Red Data sphaericum (Furness & Hall, 1981), it is likely habitats as their primary niches. Grimmia inhabitant of calcareous outcrops, but it is in Books mosses and liverworts (Church et al., 2001), to play a major role in the case of E. cohaerens

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Ephemerum cohaerens, an exquisite survivor of v E. cohaerens. Norbert Schnyder (Institut für Systematische Botanik, functional alluvial habitats Universität Zürich) here is a significant number of bryo- Many bryophytes are now so familiar to fact almost never observed in such a situation on the revised UK Red List (Hodgetts, 2011) phytes that are most often found in us in man-made habitats that it is often (Greven 2011). One could wonder where and in other countries’ Red Data Books. This artificial habitats. In the 20th cen- Rhynchostegium rotundifolium was growing species has a wide but discontinuous range in the difficult to understand what their natural tury, rapid urbanization and exploita- before human settlement. Holarctic, being mentioned in Eastern North tion of natural resources throughout habitat would be without human The study of the original habitats of America (Bryan & Anderson 1957; Crum & TWestern Europe have profoundly altered the synanthropic bryophytes (ecologically associ- Anderson 1981; Bryan 2005), in Asia (China intervention. Vincent Hugonnot and natural habitats of mosses and liverworts. ated with humans) can be a stimulating research and Japan; Bryan 2005) and Europe, where it Recording of bryophytes in cities and artificial colleagues takes a look at one such area. A population growing in an artificial extends from Spain to The Netherlands, and habitats has increased dramatically in the last species, Ephemerum cohaerens, habitat cannot be considered precisely equivalent from the United Kingdom to Poland. A recent few decades, and has significantly improved our with a natural one, and it is a well-established French distribution map showed a great scarcity familiar (although rare) to French and knowledge of the artificial ecology of bryophytes. fact that populations are liable to genetic of the species in France (Hugonnot et al., 2005). Tortula muralis is ubiquitous and abundant British bryologists from the inundation modification following colonization events. on concrete, mortared walls and roof tiles but zone of artificial reservoirs. From a management perspective, a good under- The inundation zone of reservoirs as a habitat is often present in only modest quantity on standing of natural habitats may be crucial for an for E. cohaerens calcareous rock outcrops in France or other crinita is almost always found on mortared accurate conservation action plan. The inundation zone of reservoirs provides parts of Europe. Riccia crystallina is found on walls in churchyards in southern France. Many Ephemerum cohaerens (Hedw.) Hampe is important habitats for mosses (Atherton et al., compacted, fine-textured substrates in gardens, bryophytes are adapted to arable land and some typically linked with artificial reservoirs in France 2010). Alternative flooding and exposure are but also in the inundation zone of natural ponds. particular species are difficult to spot outside this and in the UK, so its natural habitat is somewhat characteristic of the margins of water bodies In cities, Syntrichia papillosa is observed growing anthropogenic habitat (for example Dicranella obscure. We focused on this species because of its (Ellenberg, 1988; Rodwell, 2000), whilst on concrete, but it is a typical epiphyte of Quercus staphylina and Didymodon tomaculosus). In rarity worldwide and because it could be a useful open and moist, fine-textured substrates are in natural Mediterranean areas. Pseudocalliergon southern France, Leptophascum leptophyllum is tool in a conservation context. most characteristic. E. cohaerens shows special lycopodioides is often found in oligotrophic only observed along heavily disturbed paths in adaptations to this peculiar habitat, such as fens, but also in China clay quarries in France. or near urban areas, whilst its British occurrences The distribution ofE. cohaerens rhizoidal tubers (Pressel et al., 2005), fast Leptodictyum riparium is found growing at the are in arable fields in the south. Rhynchostegium Following the recent taxonomic revision of growth and abundant production of large base of deciduous shrubs in alluvial forests and rotundifolium is a specialist of castle walls and Holyoak (2010), six species of the genus spores (50–90 µm) that enable it to cope with also in greenhouses and on sloping tarmac roads. is never found in natural biotopes in France, Ephemerum are known to occur in Europe. specific seasonal constraints (alternating cycles For such species, it is not difficult to explain whereas its two British populations are both E. cohaerens is one of the rarest species and of waterlogging and drying). As it has been occurrences in artificial habitats as chance adjacent to lanes. In these cases, the original and is included in the Red Data List of European demonstrated that the spore bank is of utmost colonization of secondary ecological niches. natural habitat can be rather difficult to trace. Bryophytes with the status ‘Vulnerable’ (ECCB relevance in the strategy of Physcomitrium On the other hand, some species have artificial It is not difficult to see G. crinita as a typical 1995). It is also listed in the British Red Data sphaericum (Furness & Hall, 1981), it is likely habitats as their primary niches. Grimmia inhabitant of calcareous outcrops, but it is in Books mosses and liverworts (Church et al., 2001), to play a major role in the case of E. cohaerens

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too. In Europe, this species is mostly recorded status of the habitats although they are reputedly between the main channel and adjacent hill the Rhône river valley we are confident that as growing on the margins of artificial water naturally quite eutrophic (Rodwell, 2000). slopes (Figs 1 & 2). Our repeated attempts to these figures reflect the genuine abundance of bodies (Hill et al., 1994; ECCB, 1995; Ahrens find the species in the river channel bed failed, the species. Only one population is not in an in Nebel & Philippi, 2000; Dierssen, 2001; The example of Rhône river valley (France) even though apparently suitable microhabitats of artificial reservoir. With regard to bryophyte Infante & Heras, 2005). Rarely the species grows Ongoing bryological surveys in south-eastern bare and moist substrates are very frequent. assemblages, it is worth noting the occurrence in stubble fields (Delarze et al., 1998) and except- France surprisingly revealed that E. cohaerens Seven E. cohaerens populations have been of other ephemeral species as Aphanorrhegma ionally in a Schoenus nigricans mire (Rogeon, is rather frequent in artificial gravel pits in the discovered recently. In view of the scarcity patens, Bryum klinggraeffii and several liver- 1975). Very little is known regarding the nutrient Rhône valley, while totally absent at the margins of abandoned and unforested gravel pits in worts (Aneura pinguis, Riccia cavernosa) that of the fluctuating Rhône channel or connected are typical inhabitants of water-body margins

, Fig. 1. Location (red dots) of E. cohaerens populations lateral arms of the river. This led the authors to , Fig. 2. Photographs of the localities of E. cohaerens. (Table 1). The distance between the populations in the Rhône valley. 1, Ain confluence; 2, Miribel- search for explaining factors. E. cohaerens appears 1, Ain confluence; 2, Miribel-Jonage; 3, Tournon sur and the main channel is very variable, from more Jonage; 3, Tournon sur Rhône; 4, Canal de Montélimar. strictly located within the Rhône flood plain, Rhône; 4, Canal de Montélimar. than 1 km to 100 m (Table 1). Notwithstanding

1 2 1 2

3 4 3 4

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1 2 1 2

3 4 3 4

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Table 1. Characteristics of the populations of E. cohaerens in a natural situation. However, it is remote from could be more widespread than previously the main channel, dominated by groundwater realized in reservoirs of the Garonne valley where Locality No. of Habitat Associated species Water input Distance from the seepage and rainfall inputs, and is only connected a frequent associate is Riccia cavernosa (Celle et populations main channel (m) during major flood events. al., 2010). This is at odds with observations in 1 – Ain confluence 1 Oxbow lake Bryum pseudotriquetrum Groundwater + 750 Significantly, in the Rhône valley, Hippuris the UK, however, where records come from five Calliergonella cuspidata rainfall inputs vulgaris and Nitella hyalina are two common and reservoirs and an artificial lake in England, none Leptodictyum riparium typical oligotrophic associates. For charologists, of which is associated with a large river. It is also 2 – Miribel-Jonage 4 Artificial Aneura pinguis Groundwater + 1,100 it is a well-known fact that some species of Chara at odds with the nine Irish populations, most reservoir: Bryum gemmiferum rainfall inputs or Nitella are restricted to localities with clear of which come from the margins of fluctuating gravel pit Bryum pseudotriquetrum water and very low nutrient content (Krause, natural loughs. 1981; Simon & Nat, 1996). Calliergon cuspidatum From a general point of view, in a naturally Lessons for site management Cratoneuron filicinum functioning river valley, channel dynamics lead Regarding site management, oligotrophic waters Drepanocladus aduncus to dramatic changes in stability and create bare are essential for the maintenance and expansion Leptodictyum riparium habitats when meanders are cut off to form of E. cohaerens, so nutrient enrichment should Pellia endiviifolia oxbow lakes. The water quality in the active be controlled. The aggregated effects of chem- Philonotis calcarea channel is very different from the underground ical inputs (human sources of nitrogen, phos- Pohlia melanodon water infiltrating from the river or from the phorus and other pollutants) and the prevailing 3 – Tournon sur 1 Artificial Barbula unguiculata Groundwater + 150 ground (phreatic) water table of abandoned transport of fine sediment in river channels have Rhône reservoir: Bryum argenteum rainfall inputs channels. In the Rhône river valley mesotrophic greatly contributed to water quality deterior- gravel pit Bryum pseudotriquetrum communities are replaced by oligotrophic ones ation. The improvement of overall water quality Hygroamblystegium varium towards the margin of the floodplain (Bornette & is usually only conceivable at a catchment scale Leptobryum pyriforme Amoros, 1991). In strongly man-influenced river and is therefore beyond the reach of most site Leptodictyum riparium valleys, such as the Rhône, large-scale connectivity managers. However, the observations from France does not allow oligotrophic vegetation to emphasize the need to maintain oligotrophic Pellia endiviifolia develop. Instead, hydrological isolation provides conditions at the British and Irish sites, and raise 4 – Canal de 1 Artificial Aphanorrhegma patens Groundwater + 100 optimal conditions for oligotrophic amphibious concerns for the Sussex population, which is a Montélimar reservoir: Bryum klinggraeffii rainfall inputs bryophyte communities to grow. In a sense, E. very popular site for feeding ducks and swans. gravel pit Dicranella schreberiana cohaerens could well be considered as a powerful It is not recommended to favour the creation Dicranella staphylina indicator of hydrological isolation from flooding of new gravel pits because quarry owners do not Leptobryum pyriforme by water from the main river channel. Here, need our recommendations to severely exploit Oxyrrhynchium hians phreatic artificial reservoirs are ecological refugia available natural resources: new gravel pits will Riccia cavernosa for E. cohaerens. continue to appear here and there in the Rhône The distribution of E. cohaerens in Baden- valley. Hence the best way to conserve dynamic their distance from the main channel, all popu- majority of them (6 out of 7) are located at the Württembergs (Ahrens in Nebel & Philippi, populations of E. cohaerens there is surely to lations have developed on alluvial deposits left by margins of water bodies located in abandoned 2000; Meinunger & Schröder, 2007) and older favour a return to a more natural functioning. the past meanderings of this large, mature river. gravel pits. These artificial reservoirs have a very mentions of the species (Limpricht, 1890) closely The subtle balance between re-energization of low connectivity to the Rhône and are only fed reflect the dependence towards large functional the river and management of human pressures is Natural versus artificial stations by aquifers that provide nutrient-poor waters. hydrosystems, another example being the Rhine difficult to attain, and remains to a large extent E. cohaerens populations were encountered The population located around the dynamic in Vanderpoorten et al. (1995). A recent survey illusory. Experiments in Switzerland (Cosandey in two distinct ecological situations. The vast confluence of the Ain and Rhône is the only one in south-western France suggests that E. cohaerens & Rats, 2007) showed nevertheless that the

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re-energization of riparian habitats was possible hydrology of a braided river floodplain. Journal of Vegetation Hampe and E. spinulosum Bruch & Schimp. (Ephemeraceae, dimensions underground. Journal of Bryology 27, 311–318. at the local level, without an increase in exposed Science 2, 497–512. Bryopsida), new to the Iberian Peninsula. Cryptogamie. Rodwell, J.S. (editor) (2000). British Plant Communities. Bryologie 26, 327–333. alluvium. Bryan, S.V. (2005). Bryophyte Flora of North America – Volume 5. Maritime communities and vegetation of open Krause, W. (1981). E. cohaerens is unable to tolerate shade, so Ephemeraceae. www.nybg.org/bsci/bfna/ephemera.html Characeen als Bioindikatoren für den habitats. Cambridge: Cambridge University Press. Bryan, S.V. & Anderson, L.E. (1957). Gewässer-zustand. Limnologica 13, 399–418. encroachment by riverine shrubs and trees should The Ephemeraceae in Rogeon, M.A. (1975). Ephemerum cohaerens (Hedwig) Hampe North America. The Bryologist 60, 67–102. Limpricht, K.G. (1890). Die Laubmoose Deustchlands, var. flotowianum (Funck) Hampe: muscinée nouvelle pour le be kept at a minimal level and planting totally Celle, J., Menand, M. & Wright, M. (2010). Au sujet de trois Oesterreichs und der Schweiz. I. Leipzig: E. Kummer. Centre-Ouest de la France. Bulletin de la Société Botanique du precluded. Paradoxically, water eutrophication Ricciacées rares en Midi-Pyrénées. Isatis 31, 153–167. Meinunger, L. & Schröder, W. (2007). Verbreitungsatlas der Centre-Ouest, N.S. 6, 105–108. and vegetation succession are only problematic in Church, J.M., Hodgetts, N.G., Preston, C.D. & Stewart, Mosse Deutschlands, Band 2. Regensburg: Herausgegeben Simons, J. & Nat, E. (1996). Past and present distribution of artificial hydrosystems: in natural hydrosystems, N.F. (2001). British Red Data Books mosses and liverworts. von O. Dürhammer für die Regensburgische Botanische stoneworts (Characeae) in The Netherlands. Hydrobiologia the spontaneous rejuvenating effects of cyclic Peterborough: Joint Nature Conservation Committee. Gesellschaft. 340, 127–135. flooding are regular phenomena. Today, in the Cosandey, A.-C. & Rats, S. (2007). Etat des revitalisations Nebel, M. & Philippi, G. (2000). Die Moose Baden- Vanderpoorten, A., Klein, J.-P. & De Zuttere, P. (1995). Rhône valley, recreation of regressive successions dans les zones alluviales d’importance nationale. Evaluation de Württembergs, Band 1. Stuttgart: Verlag Eugen Ulmer. Caractéristiques bryologiques d’un système forestier alluvial in already existing gravel pits requires expensive l’enquête de 2006 auprès des cantons. Programme des Inventaires Pressel, S., Matcham, H.W. & Duckett, J.G. (2005). Studies of partiellement déconnecté du Rhin: la Réserve Naturelle d’Offendorf (Alsace, France). Écologie 26, 215–224. intervention. de biotopes. Bern: Offices fédéral de l’environnement (OFEV). protonemal morphogenesis in mosses. X. Ephemeraceae; new Life traits of E. cohaerens (large quantities Crum, H.A. & Anderson, L.E. (1981). Mosses of Eastern North America, Vol. 1. New York: Columbia University Press. of tubers and spores) seem advantageous in Delarze, R., Gonseth, Y. & Galland, P. (1998). Guide des milieux a strongly man-influenced valley. It is highly Erratum naturels de Suisse. Ecologie, menace, espèces caractéristiques. La probable that significant numbers of spores are Bibliothèque du Naturaliste, Delachaux et Niestlé. carried from one artificial pond to another by Dierssen K. (2001). Distribution, ecological amplitude and Bosanquet, S. (2012). Vagrant epiphytic mosses migrating birds, and that is also likely to be the phytosociological characterization of European bryophytes. in England and Wales. Field Bryology 107, 3–17 case in the British reservoirs and Irish loughs. Bryoph Biblioth 56, 1–289. Studies involving the life span of spores buried in Ellenberg, H. (1988). Vegetation Ecology of Central Europe. On p. 13 of the above article, the photographs the sediment are urgently needed to determine Cambridge: Cambridge University Press. were incorrectly labelled. The correct labelling of with accuracy the optimal frequency of seasonal ECCB (1995). Red Data Book of European Bryophytes. European these photographs is shown here. water fluctuations of artificial ponds. Committee for Conservation of Bryophytes. The Editor and author apologize for this Furness, S.B. & Hall, R.H. (1981). An explanation of the error. Acknowledgments intermittent occurrence of Physcomitrium sphaericum Sam Bosanquet provided insightful comments that significantly (Hedw.) Brid. Journal of Bryology 11, 733–742. x Orthotrichum rogeri. Michael Lüth improved an earlier version of this text. Greven H. (2011). Ecology and distribution of Grimmia crinita Brid. Field Bryology 104, 18–21. Vincent Hugonnot, Jaoua Celle & Hill, M.O., Preston, C.D. & Smith, A.J.E. (1994). Atlas Thierry Vergne of the bryophytes of Britain and Ireland. Volume 3. Mosses Conservatoire Botanique National du Massif (Diplolepideae). Colchester: Harley Books. Central, pôle bryophytes, le Bourg, 43 230 Hodgetts, N.G. (2011). A revised Red List of bryophytes in Chavaniac-Lafayette, France (e vincent. Britain. Field Bryology 103, 40–49. [email protected] Holyoak, D.T. (2010). Notes on taxonomy of some European species of Ephemerum (Bryopsida: Pottiaceae). Journal of References Bryology 32, 122–132. Atherton, I., Bosanquet, S. & Lawley, M. (2010). Mosses Hugonnot, V., Boudier, P. & Chavoutier, J. (2005). Ephemerum and Liverworts of Britain and Ireland: a field guide. British cohaerens (Hedw.) Hampe, répartition et écologie en France. Bryological Society. Cryptogamie Bryologie 28, 267–279. Bornette, G. & Amoros, C. (1991). Aquatic vegetation and Infante M. & Heras P. (2005). Ephemerum cohaerens (Hedw.) x Orthotrichum philibertii. Michael Lüth

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