Host shifts in fungi caused by climate change? Alan C. GANGE a, *, Edward G. GANGE a , Aqilah B. MOHAMMAD a , Lynne BODDY b a School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom b Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom article info Article history: Received 26 March 2010 Revision received 9 July 2010 Accepted 22 September 2010 Available online 28 October 2010 Corresponding editor: Anne Pringle Keywords: Community structure Competition Fungal fruiting Wood-decay fungi abstract Understanding the factors that govern the occurrence and abundance of fungal species is critical to their conservation. Here, we show that the host range of a common species, Auricularia auricula-judae, has changed in the UK over the last 59 yr. Over this time, the species has shown altered phenology, with earlier appearance of fruit bodies and a longer fruiting period, consistent with a response to observed warming trends in climate. Coin- cidental with the change in fruiting time is an expansion of its host range. We discuss how sampling artefacts are unlikely to be responsible for these changes and instead suggest that climate change has altered the competitive balance between fungal species that inhabit dead wood. Changing temperature and rainfall regimes cause different germina- tion rates, growth rates and combative ability of one species relative to another, and in the case of A. auricula-judae may have resulted in the ability to colonise a wider host range. Thus, fungal host range must be thought of as a dynamic concept when formulating conservation strategies. ª 2010 Elsevier Ltd and The British Mycological Society. All rights reserved. Introduction Many species of fungi, particularly those that are intimately associated with living hosts, i.e. those that are pathogenic, endophytic or mycorrhizal, exhibit narrow host ranges while saprotrophs exhibit varying degrees of host selectivity (Zhou & Hyde 2001). Amongst wood-decay fungi, there is evidence of host selectivity of some species from tropical wetlands and mangrove forest to temperate deciduous and boreal forest (Boddy 2001; Gilbert & Sousa 2002; Boddy & Heilmann-Clausen 2008; Gilbert et al. 2008). Determination of selectivity is usually based on the presence of fruit bodies, but absence of fruit bodies does not necessarily indicate absence of mycelia. The causes of host selectivity of wood-decay species are complex and include wood chemistry, wood microclimate, gaseous regime and the ways in which fungi become established (Boddy 2001). Environmental factors limiting plant distribution may also contribute to selectivity (Gilbert et al. 2008). Assessments of host selectivity based on fruit bodies are likely to be incorrect, because they do necessarily reflect the presence of mycelia, and most surveys take place for short periods and often at specific times of year. In any sampling programme, measured species diversity increases with effort - the so-called species accumulation effect (Henderson 2008). Species richness can be estimated using accumulation curves coupled with statistical models (Unterseher et al. 2008) or by using tree species number as a predictor of macrofungal diversity (Schmit et al. 2005), and these methods have been successfully applied to wood-decay fungi (Unterseher et al. 2008). However, to date no study has applied these tech- niques to the host range of wood-decay fungi. A further fact that has not been considered previously is whether fungi change their host ranges over time. This type of analysis is even more difficult, as it involves separating the sampling effect from real biological changes. Analyses such as these require a very long-term data set of sampling for fruit * Corresponding author. Tel.: þ44 1784 443188; fax: þ44 1784 414224. E-mail address: a.gange@rhul.ac.uk (A.C. Gange). available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/funeco 1754-5048/$ e see front matter ª 2010 Elsevier Ltd and The British Mycological Society. All rights reserved. doi:10.1016/j.funeco.2010.09.004 fungal ecology 4 (2011) 184 e190