DOI: 10.5061/dryad.2547d7x0r
title: Data from: Species richness and evenness of European bird communities show differentiated responses to measures of productivity

description: Understanding patterns of species diversity is crucial for ecological
 research and conservation, and this understanding may be improved by
 studying patterns in the two components of species diversity, species
 richness and evenness of abundance of species. Variation in species
 richness and evenness has previously been linked to variation in total
 abundance of communities as well as productivity gradients. Exploring both
 components of species diversity is essential because these components
 could be unrelated or driven by different mechanisms. The aim of this
 study was to investigate the relationship between species richness and
 evenness in European bird communities along an extensive latitudinal
 gradient. We examined their relationships with latitude and Net Primary
 Productivity, which determines energy and matter availability for
 heterotrophs, as well as their responses to territory densities (i.e., the
 number of territories per area) and community biomass (i.e., the bird
 biomass per area). We applied a multivariate Poisson log-normal
 distribution to unique long-term, high-quality time-series data, allowing
 us to estimate species richness of the community as well as the variance
 of this distribution, which acts as an inverse measure of
 evenness. Evenness in the distribution of abundance of species in
 the community was independent of species richness. Species richness
 increased with increasing community biomass, as well as with increasing
 density. Since both measures of abundance were explained by NPP, species
 richness was partially explained by energy-diversity theory (i.e., the
 more energy, the more species sustained by the ecosystem). However,
 species richness did not increase linearly with NPP but rather showed a
 unimodal relationship. Evenness was not explained either by productivity
 nor by any of the aspects of community abundance. This study
 highlights the importance of considering both richness and evenness to
 gain a better understanding of variation in species diversity. We
 encourage the study of both components of species diversity in future
 studies, as well as use of simulation studies to verify observed patterns
 between richness and evenness.
description: The following information is also given in the main manuscript.
 <strong>The individual contributors should be contacted for more
 information or permissions to work with their respective data
 sets.</strong> 276 of the plots come
 from the British Trust for Ornithology’s (BTO) Common Bird Census (CBC)
 and the BTO/Joint Nature Conservation Committee/Royal Society for the
 Protection of Birds, Breeding Bird Survey (BBS) (Marchant, 1990;
 Freeman<em> </em>et al., 2007). Two
 additional plots from the UK were obtained from Williamson (1975) and
 Gaston and Blackburn (2008). 78 plots from Germany
 were provided by Bowler and Schwarz (pers. comm.), see Schwarz and Flade
 (1989) and Kamp<em> et al.</em> (2021). 2
 plots from Estonia were provided by Leivits (pers. comm.).
 7 plots from Poland were obtained from Tomiałojć and Wesołowski
 (1996) and Wesołowski<em> et al.</em> (2002). 
  6 plots from Sweden were obtained from Enemar et al. (2004),
 Svensson (2006 & 2009). 2 plots from Finland
 were obtained from Palmgren (1987) and Lehikoinen<em> </em>et
 al. (2016) 3 plots from Norway were included (own
 data, as well as Moksnes (1978) and Hogstad (1993)).
 <strong>References:</strong>
 Enemar, A., Sjöstrand, B., Andersson, G. & Von
 Proschwitz, T. (2004) The 37-year dynamics of a subalpine passerine bird
 community, with special emphasis on the influence of environmental
 temperature and Epirrita autumnata cycles. <em>Ornis
 Svecica,</em> <strong>14,</strong> 63-106.
 Freeman, S.N., Noble, D.G., Newson, S.E. & Baillie, S.R.
 (2007) Modelling population changes using data from different surveys: the
 Common Birds Census and the Breeding Bird Survey. <em>Bird
 Study,</em> <strong>54,</strong> 61-72.
 Gaston, K. & Blackburn, T. (2008) Pattern and process in
 macroecology. Hoboken.<em> </em>NJ, John Wiley &
 Sons. Hogstad, O. (1993) Structure and dynamics of a
 passerine bird community in a spruce-dominated boreal forest. A 12-year
 study. <em>Annales Zoologici Fennici</em>, pp.
 43-54.<em> </em>JSTOR. Kamp, J., Frank, C.,
 Trautmann, S., Busch, M., Dröschmeister, R., Flade, M., Gerlach, B.,
 Karthäuser, J., Kunz, F. & Mitschke, A. (2021) Population trends
 of common breeding birds in Germany 1990–2018. <em>Journal of
 Ornithology,</em> <strong>162,</strong> 1-15.
 Lehikoinen, A., Fraixedas, S., Burgas Riera, D., Eriksson, H.,
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 <em>Ornis Fennica,</em>
 <strong>93</strong>. Marchant, J.H.
 (1990) <em>Population trends in British breeding birds</em>.
 British Trust for Ornithology. Moksnes, A. (1978)
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 med planene om tilleggsreguleringer i Neavassdraget, Tydal
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 & Flade, M. (1989) Ergebnisse des DDA-Monitoringprogramms.
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 seit</em><strong>,</strong> 87-106.
 Svensson, S. (2006) Species composition and population
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 Tomiałojć, L. & Wesołowski, T. (1996) Structure of
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 <strong>31,</strong> 133-154. Wesołowski,
 T., Tomiałojć, L., Mitrus, C. & Rowiński, P. (2002) The breeding
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description: # Species richness and evenness of European bird communities show
 differentiated responses to measures of productivity
 [https://doi.org/10.5061/dryad.2547d7x0r](https://doi.org/10.5061/dryad.2547d7x0r) ## Description of the data and file structure See the main manuscript for details about the individual sources of the data set. The uploaded data set includes all additional data used in the analysis, such as Plot, Year, Species, Count, CommBio_Area, Area, Pairs_Area, NPP, GPP, Latitude, Habitat, and Country. **Code/Software** Attached is the R-code for the model that we developed in this manuscript. Packages needed to run the code are listed in the script. The data set was saved using the "fwrite" function from the "data.table" package and should be loaded using the "fread" function from the same package.