Abstract Detail

Ecological Section

Amend, Anthony Stuart [1], Martiny, Adam C. [2], Martiny, Jennifer B. H. [3].

Phylogenetic insights into fungal community composition and function under climate change: a future living with close relatives and picky eaters.

Fungi play a critical role in the degradation of organic matter. Because different combinations of fungi result in different rates of decomposition, determining how climate change will affect fungal composition and function is fundamental to predicting future environments. However, the high number of fungal species in any given location constrains our ability to predict the fate of individuals and their contributions to ecosystem processes following perturbation. This complexity may be reduced, theoretically, if changes in community composition are non-random with respect to phylogeny and are "clustered" at taxonomic ranks higher than species. Here we investigate the potential for using a phylogenetic, trait-based framework to capture the response of leaf litter degrading fungi to global change. We present the results of a long-term manipulation experiment in which replicated grassland plots were subjected to drought and nitrogen fertilization within the range of predicted future conditions. Fungal communities were characterized using high-throughput sequencing of phylogenetically informative DNA markers (nuLSU). To test whether phylogenetic patterning correlates with decomposition rates, fungi were isolated and deployed in microcosms as mock communities along a gradient of community clustering. Nearly all fungal communities from field sites were significantly more phylogenetically clustered than randomized predictions. Proportional changes in abundance were highly correlated with relatedness, such that relatives with approximately 95% nuLSU genetic identity showed similar responses to the treatments. A microbe’s change in relative abundance was significantly correlated between the treatments, suggesting a compromise between numerical abundance in undisturbed environments and resistance to change in general, independent of disturbance type. Lineages in which at least 90% of the fungi shared the same response were circumscribed at a phylogenetic depth that is significantly greater than randomized simulations predict. We show that a microbe’s response to the manipulations is correlated with its potential functional traits (measured here as the number of glycoside hydrolase genes encoding the capacity to degrade different types of carbohydrates). Whereas nitrogen fertilization of microcosms increased cumulative respiration by 24.8%, phylogenetic diversity failed to predict respiration rates or their change in response to nitrogen fertilization. There was no correlation between community similarity and respiration rates. We show how a phylogenetic framework may be used to aggregate individuals into a finite number of response groups. Together, these results suggest that a phylogenetic, trait-based framework may be useful for predicting shifts in microbial composition and function in the face of global change.

1 - University of Hawaii at Manoa, Botany, 3190 Maile Way, Honolulu, HI, 96822, USA
2 - University of California, Irvine, Earth System Science and Ecology and Evolutionary Biology, Irvine, CA, 92697, USA
3 - University of California, Irvine, Ecology and Evolutionary Biology, Irvine, CA, 92697, USA

Keywords:
climate change
ecosystem function
microbial ecology
phylogenetic clustering
response traits
phylogenetic diversity
nitrogen addition
microcosm
Community ecology.

Presentation Type: Oral Paper:Papers for Sections
Session: 35
Location: Salon 6/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 11:30 AM
Number: 35014
Abstract ID:327
Candidate for Awards:None