Scientific interests:

My main scientific interest is numerical ecology, with aspects of species distribution and biodiversity (alpha and beta diversity) in relation to effects of climate change. Recent activities has involved application of mixed effect models for clustered data with spatial and temporal correlations.

Other ecological topics; aquatic macrophytes of Northern Ireland (species environmental relationships, beta-diversity and scale dependent trends of species richness), alpine plants (spatial longitudinal data for distribution of species, species composition), estimation of age-depth relationships for paleorecords, bryophytes (Andreaea: species-environmental relationships, reproduction-environmental relationship and morphology-environmental relationship, Ulota crispa: species distribution environment or dispersion), species richness to productivity relationships across spatial scales, sea urchins (experimental approaches), biological managing (heathland) and acidification recovery (chironomids).

Links to stats pages

R

Simon Wood

Thomas Yee

Stephane Dray

Pierre Legendre

LLMM

Age-Depth

Publications:

Bakke, J., Lie, Ø., Heegaard, E., Dokken, T., Haug, G.H., Birks, H.H., Dulski, P. & Nilsen, T. Rapid oceanic and atmospheric changes during the Younger Dryas cold period. Nature Geoscience 2: 202-205.

Heegaard, E. & Nilsen, T. 2009. In the mixed world of predictive biology--contradiction or support? Ecological Modelling 220: 1461-1468.

Bellerby, R., Schulz, K.G., Riebesell, U., Neill, C.C., Nondal, G., Heegaard, E., Johannessen, T. & Brown, K. 2008. Marine ecosystem community carbon and nutrient uptake stoichiometry under varying ocean acidification during the PeECE III experiment. Biogeosciences 5: 1517-1527

Grytnes, J.-A., Heegaard, E. & Romdal, T.S. 2008. Can the mass effect explain the mid-altitudinal peak in vascular plant species richness? Basic and Applied Ecology 9: 373-382.

Li, L., Høie, H., Gaffen, A., Heegaard, E., Skadal, J. & Folkvord, A. 2008. Back-calculation of previous fish-size using individually tagged and marked Atlantic cod (Gadhus morhua). Canadian Journal of Fisheries and Aquatic Sciences 65: 2496-2508.

Heegaard, E. & Nilsen, T. 2007. Local Linear Mixed Effect Models - Model specification and interpretation in a biological context. Journal of Agricultural, Biological, and Environmental Statistics 12: 414-430.

Heegaard, E., Økland, R.H., Bratli, H., Dramstad, W.E., Engan, G., Pedersen, O. & Solstad, H. 2007. Regularity of species richness relationships to patch size and shape. Ecography 30: 589-597.

Bratli, H. Økland, T., Økland, R.H., Dramsted, W.E., Elven, R., Engan, G., Fjellstad, W., Heegaard, E., Pedersen, O., & Solstad, H. 2006. Patterns of variation in vascular plant species richness and composition in SE Norwegian agricultural landscapes. Agricultural, Ecosystems, & Environment 114: 270-286.

Grytnes, J.-A., Heegaard, E. & Ihlen, P.G. 2006. Species richness of vascular plants, bryophytes, and lichens along an altitudinal gradient in western Norway. Acta Oecologia 29: 241-246.

Heegaard, E., Lotter, A.F. & Birks, H.J.B. 2006. Aquatic biota and the detection of climate change: are there cosistent aquatic ecotones? Journal of Paleolimnology 35: 507-518.

Gjerde, I., Sætersdal, M., Rolstad, J., Storaunet, K.O., Blom, H.H., Gundersen, V. & Heegaard, E. 2005.
Productivity-diversity relationships in six northern forest landscapes. Ecography 28: 705-720.

Heegaard, E., Birks, H.J.B. & Telford, RJ. 2005. Relationships between calibrated ages and depth in stratigraphical sequences: an estimation procedure by mixed-effect regression. The Holocene 15: 612-618.

Vandvik, V., Heegaard, E., Måren, I.E. & Aarrestad, P.A. 2005. Managing heterogeneity: the importance of grazing and environmental variation on post-fire succession in heathlands. Journal of Applied Ecology 42: 139-149.

Heegaard, E. 2004. Trends in aquatic macrophyte species turnover in Northern Ireland – which factors determine the spatial distribution of local species turnover? Global Ecology and Biogeography 13: 397- 408.

Heegaard E. & Vandvik V. 2004. Climate change affects the outcome of competitive interactions – an application of principal response curves. Oecologia 139: 459-466.

Jarngerdur, G. Aradottir, A.L., Vandvik, V., Heegaard, E. & Birks, H.J.B. 2004. Long-term effects of reclamation treatments on plant succession in Iceland. Restoration Ecology 12: 268-278.

Mohr, F., Ekman, S. & Heegaard, E. 2004. Evolution and taxonomy of the marine Collemopsidium (lichenized Ascomycota) in north-west Europe. Mycological Research 108: 515-532.

Sylvi M. Sandvik, Heegaard E. & Vandvik V. 2004. Responses to alpine snowbed vegetation to long-term experimental warming. Ecoscience 11: 150-159.

Telford, R.J., Heegaard, E. & Birks, H.J.B. 2004. All age-depth models are wrong: but how badly? Quaternary Science Reviews 23: 1-5.

Telford, R.J., Heegaard, E. & Birks, H.J.B. 2004. The intercept is a poor estimate of a calibrated radiocarbon age. Holocene 14: 296-298.

Totland Ø, Grytnes JA & Heegaard E. 2004. Willow canopies and plant community richness and composition along an alpine environmental gradient. Antarctic, Arctic and Alpine Research 36: 414-421.

Birks, HJB & Heegaard E 2003. Developments in Age-depth modelling of Holocene stratigraphical sequences. Pat Global Changes 11: 7-8.

Halvorsen, G.A., Heegaard, E., Fjellheim, A.& Raddum, G.G. 2003. Tracing recovery from acidification in the western Norwegian Nausta watershed - a multivariate approach. Ambio 32: 235-239.

Sylvi M. & Heegaard E. 2003. Effects of simulated environmental changes on growth and growth-form in a late snow-bed population of Pohlia wahlenbergii (Web. et Mohr) Andr. Antarctic, Arctic and Alpine Research 35: 341-348.

Whittaker, RJ. & Heegaard, E. 2003. What is the observed relationship between species richness and productivity? Ecology 84: 3384-3390.

Battarbee, R.W., Grytnes, J.-A., Thompson, R., Appleby, R.G., Catalan, J., Korhola, A., Birks, H.J.B., Heegaard, E. & Lami, A. 2002. Comparing palaeolimnological and instrumental evidence of climate change for remote mountain lakes over the last 200 years. Journal of Paleolimnology 28: 161-179.

Heegaard E. 2002. The outer border and central border for species-environmental relationships estimated by non-parametric generalised additive models. Ecological Modelling 157: 131-139.

Heegaard E. 2002. A model of alpine species distribution in relation to snow-melt time and altitude. Journal of Vegetation Science 13: 493-504.

Heegaard E. 2001. Environmental relationships of perichaetial and sporophyte production in Andreaea spp in western Norway. Journal of Bryology 23: 97-108.

Heegaard E, Birks HH, Gibson CE, Smith SJ & Wolfe-Murphy S. 2001. Species-environmental relationships of aquatic macrophytes in Northern Ireland. Aquatic Botany 70: 175-223.

Øvstedal D.O. & Heegaard E. 2001. Biodiversity and vegetation dynamics in the coastal heathlands of western Norway. Nordic Journal of Botany 21: 283-290.

Grytnes J.-A, Birks H.J.B., Heegaard E. & Peglar S.M. 2000. Geographical trends in the species-to-family ratio of vascular plants in Fennoscandia. Norsk Geografisk tidsskrift 54: 60-64.

Heegaard E. 2000. Patch-dynamics and/or species-environmental relationship in conservation bryology. Lindbergia, 25: 85-88.

Heegaard E. & Hangelbroek H.H. 1999. The distribution of Ulota crispa at a local scale in relation to both dispersal- and habitat-related factors. Lindbergia, 24: 65-74.

Birks H.J.B., Heegaard E., Jonsgard B. & Birks H.H. 1998. Quantifying Bryophyte - Environment Relationships. I: N. W. Ashton, J. W. Bates & J. G. Duckett (ed.), Bryology for the Second Century. British Bryological Society, W.S. Maney & Son Ltd.

Heegaard E. 1997. Ecology of Andreaea in western Norway: A quantitative analysis. Journal of Bryology, 19 (3): 527-636.

Heegaard E. 1997. Morphological variation within Andreaea blyttii Shimp. in relation to the environment on Hardangervidda, western Norway: a quantitative analysis. The Bryologist, 100 (3): 308-323.

Heegaard E. 1997. The Nordic Bryological Society’s excursion, 22nd to 26th of July 1996. Lindbergia, 22: 145-147.