Use this URL to cite or link to this record in EThOS:
Title: Identification of species limits : clarifying taxonomy and ecology of BAP lichens
Author: Bogomazova, Kristine
ISNI:       0000 0004 7425 8207
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2018
Availability of Full Text:
Access from EThOS:
Full text unavailable from EThOS. Please try the link below.
Access from Institution:
Halting the unprecedented loss of biodiversity is one of the greatest challenges humanity currently faces. However, the loss of biodiversity cannot be properly assessed and quantified without a better understanding of the underlying pattern of species diversity and distribution. This challenge is essentially a taxonomic one, and it prevents effective and targeted conservation. When dealing with organisms that display very few taxonomically useful characters, such as lichens, relying on traditional phenotype-based species recognition has proven to provide a poor estimate of true diversity, with many of the characters previously thought to be diagnostic shown to be uninformative. Knowledge gaps in taxonomy and distribution create uncertainty in identifying species at risk and can compromise our ability to create an effective conservation strategy. This thesis thus aimed to improve our understanding of the diversity, identification, and distribution of high conservation priority lichens in the UK. Three case studies were used to address some of critical uncertainties surrounding species limits. The first research chapter (CHAPTER TWO) investigates an internationally important temperate rainforest lichen– Pseudocyphellaria lacerata, which is distinguished by the morphology of its asexual propagules. Variation in these features suggests that it may in fact be a luxuriant or anomalous growth of the more common P. intricata, representing an ecological morphotype and not a distinct taxon. A multi-locus phylogenetic approach, together with complimentary analysis of morphological, chemical and environmental data, is used to understand the role of environment in shaping morphology and to resolve the taxonomic status of P. aff. lacerata in the UK. In light of molecular recognition of P. lacerata as a distinct lineage, it's extremely limited distribution in the UK is revealed. The results attribute the morphological variability observed in these taxa to phenotypic plasticity associated with differences in ecological conditions; these lichens exhibit considerable modifications to the thallus in response to a more open habitat. These results question the use of asexual propagule details as diagnostic characters for this lineage and, in light of previous research, suggest that similar classifications in other lichenised fungal groups should also be questioned. CHAPTER THREE explores the conservation challenges that come with the discovery of cryptic complexes using the high conservation priority lichen - Megalospora tuberculosa, as a case study. Most of the M. tuberculosa material from Britain is sterile, thus displaying very few, variable, and difficult-to-interpret morphological characters. In the absence of the sexual states previously required for species identification, molecular data is used for taxonomic evaluation of this species in Britain and internationally. A high level of hidden diversity is revealed in what was previously thought to be one widespread and extremely variable species – M. tuberculosa. In Britain alone, the specimens referred to as M. tuberculosa comprise three highly divergent and distinct clades. However, due to simultaneous variability of some characters and overlap between others, combined with a general lack of understanding of which characters are phylogenetically informative, circumscription of these taxa is premature. In CHAPTER FOUR, a rare and data deficient lichen Diplotomma pharcidium is used as a case-study for niche modelling with highly restricted data availability. Collecting new, highquality distribution data over a large scale is extremely costly, meaning that any efficiency gain achieved by carefully targeting specialist survey effort has potential for enormous economic as well as conservation benefit. Models to predict areas with a higher probability of hosting a target species could help focus sampling effort and increase efficiency. The challenge addressed by this chapter is to produce these model predictions for rare species under the inevitable constraint of limited data availability, particularly the limited and biased data available from previous surveys. Two approaches are compared, the accessible and popular MaxEnt approach, and the expert-led Bayesian method, each applied with and without sampling bias correction, to determine search areas for new possible locations of D. pharcidium. While both methods identified similar distribution patterns for the species, the Bayesian method models the actual pattern of occupancy, as opposed to areas of potential environmental suitability, modelled by MaxEnt. A further advantage of the Bayesian method is that the set of associated uncertainties come with predicted probability of presence, allowing us to target the sites with the highest likelihood of occupancy, and the lowest uncertainties. In this way, a model-based sampling approach increases the chance of finding new populations for protection, while at the same time reducing sampling costs.
Supervisor: Yahr, Rebecca ; Mitchell, Ruth ; Ellis, Chris ; Britton, Andrea ; Woodin, Sarah Sponsor: Macaulay Development Trust ; Royal Botanic Garden ; Edinburgh ; James Hutton Institute ; British Ecological Society
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Lichens ; Biology ; Biodiversity ; Ecology