Rare species of wood‐inhabiting fungi are not local

Abstract

Wood-inhabiting fungal communities are a diverse and ecologically critical part of forest ecosystems, yet the spatial structure of fungal biodiversity in these ecosystems is largely unknown. Legislation allowed harvesting of deadwood from temperate rainforests on conservation lands in New Zealand following Cyclone Ita in 2014. Harvesting guidelines specified widely spread harvesting, on the assumption that rare fungal species may be highly spatially restricted, but were not based on quantitative assessment. We sampled fungi in and on logs of Dacrydium cupressinum (Podocarpaceae) a long-lived, common, canopy tree in lowland New Zealand forests. DNA was extracted from 81 logs varying in decay state across a 40 km long region of West Coast (South Island) forests, and sequenced using general fungal primers for metabarcoding to identify OTUs (operational taxonomic units). We examined three axes of rarity: occupancy, dominance when present, and niche breadth (as spatial extent and decay state specialization). Low-occupancy fungi were common, including a group of infrequently occurring but dominant when present fungi, the majority of which were Ascomycota. Despite this, there was an overall positive relationship between occupancy and dominance. Widespread, dominant fungi were most commonly Basidiomycota. Testing all fungal OTUs, there were no more fungi with maximum range sizes < 4 km than would be expected at random. Of the 351 low-occupancy OTUs found two to four times, only 12 had maximum range sizes < 900 m, and there was no more spatial restriction at scales < 900 m than would be expected by random chance, although there was some evidence of niche breadth restriction based on decay state similarity. The results show that fungal communities in deadwood are highly diverse, and include many rare taxa. Nonetheless, the lack of fungal OTUs with spatial restriction at scales < 900 m suggests that spatially dispersed timber harvesting will not mitigate risks of harvesting to rare fungal biodiversity.

Successional Development of Fungal Communities Associated with Decomposing Deadwood in a Natural Mixed Temperate Forest

“…These rare species might be mainly specialists, i.e., tree species-specific, as demonstrated by Moor et al [74]. Such hypotheses highlight the existence of many rare species in deadwood [75,76] and the importance of tree species diversity to promote the global diversity of fungi in forest ecosystems [77]. Thus, our findings suggested that rare fungal species are largely involved in community dissimilarities, as already mentioned in Thorn et al [78].…”

Land use, but not distance, drives fungal beta diversity

“…This means that, biologically, sites relatively close together (under 1 km) and within the same habitat and edaphic type often had very different fungal communities, as evidenced by their high levels of turnover. Similar results were seen in fungal communities colonizing decaying wood both following a storm on the west coast of the South Island (Dickie et al 2020) as well as in a Bavarian forest in southeastern Germany (Müller et al 2020), and root endophytes in Europe (Glynou et al 2016), suggesting a lack of strong distance effects for fungal communities may be a general pattern, at least in temperate ecosystems. This may reflect strong assembly history or priority effects (Fukami et al 2010, Fukami 2015.…”

“…2012, Dickie et al. 2020]). At this scale, fungal communities, like most other systems, often have have strongly uneven species‐abundance relationships that are usually log‐normal or Pareto shaped (Dumbrell et al.…”

“…2014, Dickie et al. 2020), patterns of fungal species turnover in space or time, that is, beta diversity (Whittaker 1956, Anderson et al. 2011, Chao et al.…”

The Utility of Macroecological Rules for Microbial Biogeography

“…A A (Sintes et al, 2015;Raes et al, 2018b), B A (Amend et al, 2013;Sul et al, 2013;Wang and Soininen, 2017;Raes et al, 2018b), F A (Raes et al, 2018b), F T (Tedersoo et al, 2014;Cox et al, 2016;Ogwu et al, 2019) B T (Nemergut et al, 2011;Green et al, 2016;Stopnisek and Shade, 2020), A A (Zhou et al, 2019;Liu J. et al, 2020), B A (Pommier et al, 2007;Humbert et al, 2009;Östman et al, 2010;Nemergut et al, 2011;Liu et al, 2015;Bienhold et al, 2016;Liao et al, 2017;Mo et al, 2018), B T (Nemergut et al, 2011;Valverde et al, 2014;Ji et al, 2020), F T (Zhang et al, 2018;Gange et al, 2019;Dickie et al, 2020) F T (Helander et al, 2007;Botnen et al, 2019) F T (Tedersoo et al, 2010(Tedersoo et al, , 2012(Tedersoo et al, , 2014Timling et al, 2012;Holt et al, 2015;Glynou et al, 2016;Pärtel et al, 2017;de Menezes et...…”