Growth and tissue nitrogen of epiphytic Atlantic bryophytes: effects of increased and decreased atmospheric N deposition

Summary 1Atlantic bryophytes are of European conservation importance, yet the effect on them of excess atmospheric nitrogen is relatively unknown. This study assesses the effects of increased atmospheric N deposition on the growth and tissue N of epiphytic Atlantic bryophytes, and their potential to recover following a decline in N deposition. 2The N received in stemflow by bryophytes at two sites was measured and compared to model predictions. 3Four species of epiphytic bryophytes (Isothecium myosuroides, Dicranum scoparium, Frullania tamarisci and Ulota crispa), typical of Atlantic Oak woods, were studied in a 12-month reciprocal transplant experiment between a pristine Oak woodland receiving a modelled atmospheric deposition of 12 kg N ha−1 year−1 and a polluted one receiving 54 kg N ha−1 year−1. 4Tissue N concentration increased and growth declined following an increase in atmospheric N deposition in all species except Ulota crispa. Conversely, tissue N concentration decreased and growth increased in Frullania tamarisci following a decrease in atmospheric N deposition, with similar non-significant patterns in the other species. 5The reciprocal transplants indicate a detrimental effect of increased N deposition on the bryophyte species studied. The study indicated recovery following a decrease in atmospheric N deposition, but the responses caused by decreased N deposition were smaller than those due to increased N deposition. This suggests that the time-scale for recovery of bryophytes from excess N deposition is longer than the timescale of nitrogen impacts.

[1]  A. Smith,et al.  The Moss Flora of Britain and Ireland: Abbreviations , 2004 .

[2]  R. van der Wal,et al.  Physiological and growth responses of the montane bryophyte Racomitrium lanuginosum to atmospheric nitrogen deposition. , 2003, The New phytologist.

[3]  R. Wal,et al.  Effects of nitrogen deposition on growth and survival of montane Racomitrium lanuginosum heath , 2002 .

[4]  J. Cape,et al.  Comparison of the Effects of Wet N Deposition (NH4Cl) and Dry N Deposition (NH3) on UK Moorland Species , 2001 .

[5]  C. ter Braak,et al.  Relationship between epiphytic lichens, trace elements and gaseous atmospheric pollutants. , 2001, Environmental pollution.

[6]  Mark A. Sutton,et al.  Regional estimation of pollutant gas dry deposition in the UK: model description, sensitivity analyses and outputs , 2000 .

[7]  J. A. Paton,et al.  The Liverwort Flora of the British Isles , 1999 .

[8]  Markus Amann,et al.  Transboundary air pollution , 1999 .

[9]  D. Fowler,et al.  The relationship between nitrogen deposition, species composition and foliar nitrogen concentrations in woodland flora in the vicinity of livestock farms , 1998 .

[10]  J. Pearson,et al.  Short-Term Physiological Responses of Mosses to Atmospheric Ammonium and Nitrate , 1997 .

[11]  N. Hodgetts.  Atlantic bryophytes in Scotland , 1997 .

[12]  I. Jónsdóttir,et al.  Measuring growth rates in bryophytes and lichens , 1997 .

[13]  H. F. Dobben,et al.  Re‐mapping epiphytic lichen biodiversity in The Netherlands: effects of decreasing SO2 and increasing NH3 , 1996 .

[14]  T. Callaghan,et al.  Growth responses of Polytrichum commune and Hylocomium splendens to simulated environmental change in the sub-arctic. , 1995, The New phytologist.

[15]  S. Bakken.  Effects of nitrogen supply and irradiance on growth and nitrogen status in the moss Dicranum majus from differently polluted areas , 1995 .

[16]  S. Bakken.  Regional variation in nitrogen, protein and chlorophyll concentration in Dicranum majus — a reciprocal transplantation experiment , 1995 .

[17]  J. Grace,et al.  Deposition of fixed atmospheric nitrogen and foliar nitrogen content of bryophytes and Calluna vulgaris (L.) Hull. , 1995, Environmental pollution.

[18]  J. W. Bates.  Influence of chemical and physical factors on Quercus and Fraxinus epiphytes at Loch Sunart, western Scotland : a multivariate analysis , 1992 .

[19]  John A. Lee,et al.  Effects of nitrogen oxides on nitrate assimilation in bryophytes , 1992 .

[20]  G. Dirkse,et al.  Effects of fertilizer on bryophytes in Swedish experiments on forest fertilization , 1992 .

[21]  J. W. Bates.  Mineral nutrient acquisition and retention by bryophytes , 1992 .

[22]  S. Bell,et al.  Effects of rural roadside levels of nitrogen dioxide on Polytrichum formosum Hedw. , 1992, Environmental pollution.

[23]  A. Farmer,et al.  Seasonal variations in acidic pollutant inputs and their effects on the chemistry of stemflow, bark and epiphyte tissues in three oak woodlands in N.W. Britain , 1991 .

[24]  J. W. Bates,et al.  Bryophytes and nutrient cycling , 1990 .

[25]  J. Lee,et al.  THE EFFECTS OF NITRATE, AMMONIUM AND TEMPERATURE ON NITRATE REDUCTASE ACTIVITY IN SPHAGNUM SPECIES. , 1987, The New phytologist.

[26]  M. Press,et al.  THE POTENTIAL IMPORTANCE OF AN INCREASED ATMOSPHERIC NITROGEN SUPPLY TO THE GROWTH OF OMBROTROPHIC SPHAGNUM SPECIES , 1986 .

[27]  M. Press,et al.  Nitrate reductase activity in Sphagnum fuscum in relation to wet deposition of nitrate from the atmosphere , 1985 .

[28]  D. N. Rao.  Responses of Bryophytes to Air Pollution , 1982 .

[29]  J. Rieley,et al.  THE ECOLOGICAL ROLE OF BRYOPHYTES IN A NORTH WALES WOODLAND , 1979 .

[30]  J. R. Brett.  10 - Environmental Factors and Growth , 1979 .

[31]  D. Hawksworth,et al.  Qualitative Scale for estimating Sulphur Dioxide Air Pollution in England and Wales using Epiphytic Lichens , 1970, Nature.

[32]  O. Flint,et al.  Preliminary observations on the mineral nutrition of epiphytic mosses , 1969 .