Raised water temperature lowers diversity of hyporheic aquatic hyphomycetes

SUMMARY 1. The hyporheic zone of a permanent first-order stream was divided into a treatment and a control section using a 1 m deep sheet-metal barrier. During a 4-month pre-treatment period, water temperatures in two transects of the two sections were not different. Upon heating, the water temperature in the treatment transect increased by an average of 4.3 � C over values in the control transect. 2. Eleven bimonthly core samples were taken from a treatment and a control transect, and recovered CPOM was classified as twigs, wood, grass, roots, cedar and deciduous leaves. 3. In both transects, twigs were the most common and deciduous leaves the least common substrates. The number of leaf fragments declined significantly in the heat-treated transect. 4. Diversity and frequencies of occurrence of aquatic hyphomycetes were highest on leaves and lowest on grass and wood. On leaves, their frequency of occurrence was higher in control than in treatment samples. 5. Preliminary results with amplified and cloned 18S DNA sequences revealed many fungal taxa with high affinities to Basidiomycota, particularly to Limnoperdon incarnatum. 6. By itself, higher water temperature due to global warming is likely to lower the availability of substrates for, and therefore the occurrence of, aquatic hyphomycetes.

[1]  H. Mooney,et al.  Human Domination of Earth’s Ecosystems , 1997, Renewable Energy.

[2]  A. Covich,et al.  The Role of Biodiversity in the Functioning of Freshwater and Marine Benthic Ecosystems , 2004 .

[3]  J. Piotrowski,et al.  Abrupt rise in atmospheric CO2 overestimates community response in a model plant–soil system , 2005, Nature.

[4]  Nutrient and flow vector dynamics at the hyporheic/groundwater interface and their effects on the interstitial fauna , 1993 .

[5]  L. Boddy,et al.  Rapid and Recent Changes in Fungal Fruiting Patterns , 2007, Science.

[6]  K. Suberkropp.  Effect of temperature on seasonal occurrence of aquatic hyphomycetes , 1984 .

[7]  Michael J. Donoghue,et al.  A New Age of Discovery , 2000 .

[8]  M. Lock,et al.  Immobilization of dissolved organic matter from groundwater discharging through the stream bed , 1991 .

[9]  J. Webster,et al.  Anaerobic survival of aquatic fungi , 1983 .

[10]  C. Leyval,et al.  Extensive fungal diversity in plant roots. , 2002, Science.

[11]  F. Bärlocher,et al.  Taxon-specific fungal primers reveal unexpectedly high diversity during leaf decomposition in a stream , 2004, Mycological Progress.

[12]  R. Wetzel,et al.  Elevated-CO2-Induced Changes in the Chemistry of Quaking Aspen (Populus tremuloides Michaux) Leaf Litter: Subsequent Mass Loss and Microbial Response in a Stream Ecosystem , 2002, Journal of the North American Benthological Society.

[13]  F. Bärlocher.  Sporulation by Aquatic Hyphomycetes , 2020, Methods to Study Litter Decomposition.

[14]  D. Williams,et al.  Fungi in the Hyporheic Zone of a Springbrook , 2006, Microbial Ecology.

[15]  C. Beierkuhnlein,et al.  A new generation of climate‐change experiments: events, not trends , 2007 .

[16]  Christopher W. Schadt,et al.  Seasonal Dynamics of Previously Unknown Fungal Lineages in Tundra Soils , 2003, Science.

[17]  Nancy B. Grimm,et al.  Exchange between interstitial and surface water: Implications for stream metabolism and nutrient cycling , 1984, Hydrobiologia.

[18]  J. Newbold,et al.  Climate Change and the Life Histories and Biogeography of Aquatic Insects in Eastern North America , 1992 .

[19]  K. Sridhar,et al.  Endophytic aquatic hyphomycetes of roots of spruce, birch and maple , 1992 .

[20]  K. Sridhar,et al.  Aquatic Hyphomycetes in Polluted Groundwater Habitats of Central Germany , 2003, Microbial Ecology.

[21]  C. Parmesan.  Ecological and Evolutionary Responses to Recent Climate Change , 2006 .

[22]  F. Bärlocher.  Freshwater Fungal Communities , 2005 .

[23]  D. Hibbett,et al.  Evolution of Marine Mushrooms , 2001, The Biological Bulletin.

[24]  D. Mccabe,et al.  Limnoperdon, A Floating Gasteromycete Isolated from Marshes , 1976 .

[25]  D. Dudley Williams,et al.  Perspectives and predictions on the microbial ecology of the hyporheic zone , 1999 .

[26]  R. Naiman,et al.  Freshwater biodiversity: importance, threats, status and conservation challenges , 2006, Biological reviews of the Cambridge Philosophical Society.

[27]  R. Rempel,et al.  Temperature Influences on Adult Size, Development, and Reproductive Potential of Aquatic Diptera , 1987 .

[28]  D. Williams,et al.  SEASONAL BOUNDARY DYNAMICS OF A GROUNDWATER/ SURFACE-WATER ECOTONE , 1998 .

[29]  F. Bärlocher,et al.  Hyporheic biofilms — a potential food source for interstitial animals , 1989 .

[30]  F. Bärlocher.  Fungi on the food and in the faeces of Gammarus pulex , 1981 .

[31]  Philip Ineson,et al.  Elevated CO2, litter chemistry, and decomposition: a synthesis , 2001, Oecologia.

[32]  M. Graça,et al.  Leaf-litter breakdown in 3 streams in temperate, Mediterranean, and tropical Cerrado climates , 2006, Journal of the North American Benthological Society.

[33]  P. Bottner,et al.  Litter decomposition, climate and liter quality. , 1995, Trends in ecology & evolution.

[34]  Michael P. Cummings,et al.  PAUP* [Phylogenetic Analysis Using Parsimony (and Other Methods)] , 2004 .

[35]  V. Gulis.  Are there any substrate preferences in aquatic hyphomycetes , 2001 .

[36]  A. Boulton.  Stream ecology and surface-hyporheic hydrologic exchange: Implications, techniques and limitations , 1993 .

[37]  J. Thompson,et al.  The CLUSTAL_X windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools. , 1997, Nucleic acids research.

[38]  J. Webster,et al.  Growth and sporulation of Tricladium chaetocladium and Lunulospora curvula in relation to temperature , 1976 .

[39]  J. Webster.  Anamorph-Teleomorph Relationships , 1992 .

[40]  F. Triska,et al.  Ammonium sorption to channel and riparian sediments: A transient storage pool for dissolved inorganic nitrogen , 1994 .

[41]  Andrew J. Boulton,et al.  Hyporheic rehabilitation in rivers: restoring vertical connectivity , 2007 .

[42]  S. Running,et al.  Impacts of climate change on natural forest productivity – evidence since the middle of the 20th century , 2006 .

[43]  Jr. Jeremy B. Jones.  Benthic Organic Matter Storage in Streams: Influence of Detrital Import and Export, Retention Mechanisms, and Climate , 1997, Journal of the North American Benthological Society.

[44]  Marti J. Anderson,et al.  CANONICAL ANALYSIS OF PRINCIPAL COORDINATES: A USEFUL METHOD OF CONSTRAINED ORDINATION FOR ECOLOGY , 2003 .

[45]  Jackson R. Webster,et al.  VASCULAR PLANT BREAKDOWN IN FRESHWATER ECOSYSTEMS , 1986 .

[46]  I. Hogg,et al.  Response of Stream Invertebrates to a Global‐Warming Thermal Regime: An Ecosystem‐Level Manipulation , 1996 .

[47]  P. Harper.  Life histories of Nemouridae and Leuctridae in Southern Ontario (Plecoptera) , 1973, Hydrobiologia.

[48]  F. Bärlocher,et al.  Growth and reproduction in aquatic hyphomycetes , 1996 .

[49]  D. Wilson,et al.  Effects of elevated atmospheric CO2 on fungal competition and decomposition of Fraxinus excelsior litter in laboratory microcosms , 2000 .

[50]  Naoya Wada,et al.  Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes. , 2007, Ecology letters.