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Epiphyte Ecology
Monitoring Change
Species Discovery

Staff
Dr Brian Coppins
Ms Sally Eaton
Dr Christopher Ellis
Ms Louise Olley
Dr Rebecca Yahr

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Introduction

Our epiphyte research examining the risks to biodiversity posed by environmental change (e.g. climate change, habitat loss and pollution) is framed a within three part risk model [1] borrowed from concepts in the insurance industry (Figure 1).

 
Figure 1. A schematic for the relationship between risk factors: hazard, exposure and vulnerability. Adaptative management practices can be used to reduce vulnerability, focussing on issues such as habitat connectivity linked to dispersal and gene flow, and environmental heterogeneity linked to microclimatic refugia.
 

Risk is in response to a recognised hazard, such as climate change. The degree of risk relates to a species' exposure to the hazard, i.e. whether the species is directly sensitive to the magnitude and rate of climate change for a region of interest. This expsoure is commmonly determined using Bioclimatic Models. However, even for species that are exposed to climate change, risk may be offset by reducing vulnerability.

Reducing vulnerability is by maintaining effective biological mechanisms such as migration, evolutionary adaptation or acclimation to changing environments, and encouraging the management practices that can promote these aspects of reduced vulnerability. This management might include improved habitat connectivity for migration and gene flow (adaptation), and local interventions to increase envrionmental heterogeneity, creating the opportunity for suitable microclimates (refugia) in sub-optimal macroclimates.

Understanding Vulnerability

Our research to understand vulnerability has three key strands.

1. Adaptation and Acclimation

With Nephroma species as a model system, we are using Next Generation Sequencing to investigate patterns of photobiont specificty and selectivity along climatic gradients, matching to the photobiont availability in the wider pool of available 'free-living' cyanobacteria. This will help determine the potential for photobiont switching to optimise fitness in different environments, and in response to environmental change. On-going work is also investigating the gene pool distribution and local genetic diversity of Neproma species, from which we may infer limits to dispersal combined with the effects of habitat fragmentation.

2. Tracking Climate Change

Building on the work relating to adaptation and acclimation, it is important to consider that lichens are dual organisms with the potential to share photobionts. These multispecies interactions are a central challenge to understanding the biodiversity response to climate change. Our preliminary studies have demonstrated that sexual spore-dispersed Nephroma laevigatum may be limited in its occurrence by facilitation from the asexual Nephroma parile [2]. This completely overturns expectations under climate change scenarios, i.e. that species with smaller propagules will more easily track climate change than species with larger and heavier propagules.

3. Microhabitat Heterogeneity

Our work in Bioclimatic Modelling has demonstrated the extent to which a species' distribution might be controlled by the interaction between macroclimate and patterns of habitat quality [3, 4]. We are now using Mechanistic Models to understand how landscape features relate to specific microclimatic refugia. It might then be possible to manage additional structural complexity into a woodland stand, in order to actively promote species resilience by maintaining suitable microclimatic conditions during climate change, and population viability.

References:

[1] Ellis, C.J. (2013) A risk-based model of climate change threat: hazard, exposure and vulnerability in the ecology of lichen epiphytes. Botany, 91: 1-11.

[2] Belinchon, R., Yahr, R. & Ellis, C.J. (2015) Interactions among species with contrasting dispersal modes explain distributions for epiphytic lichens. Ecography, 38: 762-768.

[3] Lisewski, V. & Ellis, C.J. (2010) Epiphyte sensitivity to a cross-scale interaction between habitat quality and macroclimate – an opportunity for range-edge conservation. Biodiversity & Conservation, 19: 3935-3949.

[4] Lisewski, V. & Ellis, C.J. (2011) Lichen epiphyte abundance controlled by the nested effect of woodland composition along macroclimatic gradients. Fungal Ecology, 4: 241-249.