Contracting montane cloud forests: a case study of the Andean alder (Alnus acuminata) and associated fungi in the Yungas

Abstract

Alnus acuminata is a keystone tree species in the Yungas forests and host to a wide range of fungal symbionts. While species distribution models (SDMs) are routinely used for plants and animals to study the effects of climate change on montane forest communities, employing SDMs in fungi has been hindered by the lack of data on their geographic distribution. The well‐known host specificity and common biogeographic history of A. acuminata and associated ectomycorrhizal (ECM) fungi provide an exceptional opportunity to model the potential habitat for this symbiotic assemblage and to predict possible climate‐driven changes in the future. We (1) modeled the present and future distributions of suitable habitats for A. acuminata; (2) characterized fungal communities in different altitudinal zones of the Yungas using DNA metabarcoding of soil and root samples; and (3) selected fungi that were significant indicators of Alnus. Fungal communities were strongly structured according to altitudinal forest types and the presence of Alnus. Fungal indicators of Alnus, particularly ECM and root endophytic fungi, were also detected in Alnus roots. Current and future (year 2050) habitat models developed for A. acuminata predict a 25–50 percent decrease in suitable area and an upslope shift of the suitable habitat by ca. 184–380 m, depending on the climate change scenario. Although A. acuminata is considered to be an effective disperser, recent studies suggest that Andean grasslands are remarkably resistant to forest invasion, and future range contraction for A. acuminata may be even more pronounced than predicted by our models.

Changes in richness and community composition of ectomycorrhizal fungi among altitudinal vegetation types on Mount Kinabalu in Borneo

“…The indicator species analyses suggest that mid‐elevation ECM fungal communities in montane forests of Borneo are particularly rich in taxa with high specificity and fidelity to their habitat, as also suggested by the highest measured values in community similarity indices within forest types. Similarly, a large proportion of ECM fungi are known to be restricted to montane cloud forests in the Neotropics (Mueller et al ., ; Wicaksono et al ., ). Our work provides the first evidence for such altitudinal patterns in the Palaeotropics, indicating a high degree of specialization to the tropical montane forest habitat in many ECM fungi.…”

Fungi of the Fortuna Forest Reserve: Taxonomy and ecology with emphasis on ectomycorrhizal communities

“…Fungi associated with Quercus dominated forests in Mexico, Costa Rica, and Colombia are the best known montane ECM systems in the neotropics (Franco-Molano et al, 2010;Halling andMueller, 2002, 1999;Halling and Ovrebo, 1987;Morris et al, 2008;Mueller and Halling, 1995) starting with the pioneering work of Singer (1963) in oak forest of Colombia. Alnus dominated forests in Mexico, Bolivia, and Argentina have been studied to a lesser extent, for the most part, based upon sequencing of root symbiotic fungi using metagenomic approaches (Kennedy et al, 2015(Kennedy et al, , 2011Põlme et al, 2013;Wicaksono et al, 2017).…”

Niche squeeze induced by climate change of the cold-tolerant subtropical montanePodocarpus parlatorei

“…Also future ecological niche modelling for Alnus acuminata predicts losses in the low-elevation areas of the montane cloud forest and gains at higher altitudes in response to higher temperature. An upward shift of premontane forest was suggested as a general response of all Yungas vegetation strips, so that a general increase in the altitudinal levels was expected along the Andes [54,55]. Evidence of habitat reduction due to climate change in Andean environments has also been reported for bird species [46], and anomalies have been identified in the increase in trunk growth diameters due to changes in CO 2 concentration [48].…”