Biogeography of cyclamen: an application of phyloclimatic modelling

© The Systematics Association 2011. Cyclamen is a genus of popular garden plant, protected by Convention on International Trade in Endangered Species (CITES) legislation. Many of its species are morphologically and phenologically adapted to the seasonal climate of the Mediterranean region. Most species occur in geographic isolation and will readily hybridise with their sister species when brought together. We investigate the biogeography of Cyclamen and assess the impact of palaeogeography and palaeoclimate change on the distribution of the genus. We use techniques of phyloclimatic modelling (combining ecological niche modelling and phylogenetic character optimisation) to investigate the heritability of climatic preference and to reconstruct ancestral niches. Conventional and phyloclimatic approaches to biogeography are compared to provide an insight into the historic distribution of Cyclamen species and the potential impact of climate change on their future distribution. The predicted climate changes over the next century could see a northward shift of many species’ climatic niches to places outside their current ranges. However, such distribution changes are unlikely to occur through natural antbased dispersal, so conservation measures are likely to be required

Plants at risk from climate change

The popular garden flower Cyclamen grows natively in the Mediterranean. Climate change could make the region unsuitable for 18/21 species in 50 years time. Ant-dispersed Cyclamen can’t hope to migrate to suitable new areas without assistance.

Background: The impact of global climate change on plant distribution, speciation and extinction is of current concern. Examining species climatic preferences via bioclimatic niche modelling is a key tool to study this impact. There is an established link between bioclimatic niche models and phylogenetic diversification. A next step is to examine future distribution predictions from a phylogenetic perspective. We present such a study using Cyclamen (Myrsinaceae), a group which demonstrates morphological and phenological adaptations to its seasonal Mediterranean-type climate. How will the predicted climate change affect future distribution of this popular genus of garden plants? 
Results: We demonstrate phylogenetic structure for some climatic characteristics, and show that most Cyclamen have distinct climatic niches, with the exception of several wide-ranging, geographically expansive, species. We reconstruct climate preferences for hypothetical ancestral Cyclamen. The ancestral Cyclamen lineage has a preference for the seasonal Mediterranean climate characteristic of dry summers and wet winters. Future bioclimatic niches, based on BIOCLIM and Maxent models, are examined with reference to a future climate scenario for the 2050s. Over the next 50 years we predict a northward shift in the area of climatic suitability, with many areas of current distribution becoming climatically unsuitable. The area of climatic suitability for every Cyclamen species is predicted to decrease. For many species, there may be no areas with a suitable climate regardless of dispersal ability, these species re considered to be at high risk of extinction. This risk is examined from a phylogenetic
perspective.
Conclusion: Examining bioclimatic niches from a phylogenetic perspective permits novel interpretations of these models. In particular, reconstruction of ancestral niches can provide testable hypothesis about the historical development of lineages. In the future we can expect a northwards shift in climatic suitability for the genus Cyclamen. If this proves to be the case then dispersal is the best chance of survival, which seems highly unlikely for ant-dispersed Cyclamen. Human-assisted establishment of Cyclamen species well outside their native ranges offers hope and could provide the only means of dispersal to potentially suitable future environments. Even without human intervention the phylogenetic perspective demonstrates that major lineages could survive climate change even if many species are lost

Automated pre-processing strategies for species occurrence data used in biodiversity modelling

To construct Biodiversity richness maps from Environmental Niche Models (ENMs) of thousands of species is time consuming. A separate species occurrence data pre-processing phase enables the experimenter to control test AUC score variance due to species dataset size. Besides, removing duplicate occurrences and points with missing environmental data, we discuss the need for coordinate precision, wide dispersion, temporal and synonymity filters. After species data filtering, the final task of a pre-processing phase should be the automatic generation of species occurrence datasets which can then be directly ’plugged-in’ to the ENM. A software application capable of carrying out all these tasks will be a valuable time-saver particularly for large scale biodiversity studies

Tablets and Temples: Documents in Republican Rome

It has long been taken for granted that the Roman Republic, just like the elective governments of today, placed state papers in a repository to preserve them for consultation. This is assumed both in undergraduate textbooks in Roman history and in the most respected reference works used by specialists in the field. Neither the basic texts nor the standard references hesitate to use the term archive in describing this repository. That term, in fact, is Greek and was never used by the classical Romans to describe any of their own institutions. The anachronistic use of the word in reference to Roman practices has, perhaps, been responsible for much of the current misinterpretation of the significance of some of the political institutions of Republican Rome

A taxonomy of liquidity

The term “liquidity” covers many concepts but is generally taken to refer to the ease of convertibility into money. The literature classifies this ease of convertibility as “market liquidity” to distinguish it from “funding liquidity,” which represents the ease of obtaining funding. Many other forms of liquidity can be identified that do not receive their own specific classification. A more granular taxonomy that clarifies and distinguishes each form would permit greater analytical precision when investigating empirical evidence. This paper offers such a taxonomy. © 2020 Taylor & Francis Group, LLC

Mitochondrial and chloroplast DNA-based phylogeny of Pelargonium (Geraniaceae)

Overall phylogenetic relationships within the genus Pelargonium (Geraniaceae) were inferred based on DNA sequences from mitochondrial(mt)-encoded nad1 b/c exons and from chloroplast(cp)-encoded trnL (UAA) 5' exon-trnF (GAA) exon regions using two species of Geranium and Sarcocaulon vanderetiae as outgroups. The group II intron between nad1 exons b and c was found to be absent from the Pelargonium, Geranium, and Sarcocaulon sequences presented here as well as from Erodium, which is the first recorded loss of this intron in angiosperms. Separate phylogenetic analyses of the mtDNA and cpDNA data sets produced largely congruent topologies, indicating linkage between mitochondrial and chloroplast genome inheritance. Simultaneous analysis of the combined data sets yielded a well-resolved topology with high clade support exhibiting a basic split into small and large chromosome species, the first group containing two lineages and the latter three. One large chromosome lineage (x = 11) comprises species from sections Myrrhidium and Chorisma and is sister to a lineage comprising P. mutans (x = 11) and species from section Jenkinsonia (x = 9). Sister to these two lineages is a lineage comprising species from sections Ciconium (x = 9) and Subsucculentia (x = 10). Cladistic evaluation of this pattern suggests that x = 11 is the ancestral basic chromosome number for the genus

An investigation of the role of the scanning laser ophthalmoscope in the assessment of patients with macular disease

Diseases of the macula are the primary cause of blindness in the western world. Given the current lack of effective medical treatment, there is a requirement for investigation of alternative therapeutic modalities. Traditionally, low vision services provide magnifying devices and advice on illumination. However, there have been claims that training is essential for successful rehabilitation. Using the scanning laser ophthalmoscope (SLO), novel techniques have been developed for the investigation of visual function. Validation was undertaken on subjects with normal vision and patients with a variety of central field defects. Microperimetry in patients demonstrated that visual function did not always correlate with fundus appearance. In normals, small inaccuracies of fixation were found to have no measurable influence on the reproducibility of scotoma maps. Measurements of fixation indicated that the ability to maintain a steady eye position varied significantly between observers both with normal and low vision. Some patients had exceptionally poor fixation whilst in others it was normal. To minimise the problems of target acquisition due to eye movements, a scrolling text system was developed. Assessment of reading performance at specific retinal locations demonstrated that the ability to recognise letters declined with increasing retinal eccentricity and decreasing text contrast. Patients were notably worse at reading tasks than normal observers. Longitudinal evaluation of visual function was undertaken on patients entered into a low vision training programme. Most patients self-selected a single eccentric retinal location for viewing and no suggested alternative locus could be identified that provided superior performance. Although training improved visual performance, it probably resulted from enhancement of patients' psychological status and skill acquisition. This study has demonstrated the usefulness of the SLO in the functional evaluation of vision and its potential for optimising the use of residual vision in patients with macular disease

Cyclamen libanoticum, a species that knows its identity!

The species limits and infraspecific DNA sequence diversity of Cyclamen libanoticum was examined. Analysis of the chloroplast DNA from six regions shows that, in C. libanoticum, only one base-pair difference is found among samples within the analysed 7066 base-pairs. This one base-pair difference (9 ‘A’s vs 10 ‘A’s) was found in the samples collected from a single site and could represent a very minor change in DNA sequence or even show the limits or accuracy of the sequencing system used. C. libanoticum is highly distinct from other congeners in DNA sequence

Evaluation of a low vision training programme

In some countries, notably the United States and Sweden, intensive training is considered an important adjunct to low vision services in the rehabilitation of the visually handicapped. Recently, such training has been introduced into the United Kingdom. Central to many of the programmes for reading are the techniques of eccentric viewing (EV) and steady eye strategy (SES). Although the techniques have been available for the last 15 years and their justification is widely accepted, to date they have not been validated by scientific studies. Two studies were designed to test the hypothesis that intensive training improves the near vision performance with an optical magnifier. Patients with a severe central defect due to age-related macular degeneration were recruited to study "A" (N=57), and patients with a less severe defect to study "B" (N=43). One training and two comparison groups were used in each study. During initial training, 43% of patients believed that EV would be helpful for simple tasks. However, eight months later, only 6.3% in study "A" and 10% in study "B" considered that they had used EV regularly and successfully for reading. The SES had been beneficial to 12.5% in "A" and 0% in "B". There was no significant difference in the near vision performance between the group of trained patients and the comparison groups. A depression index, assessed by the General Health Questionnaire, correlated with neither the method of management nor visual performance for patients in study "A". This is the first time that a trial of this type has been undertaken. It shows that standard management is as effective as training in the rehabilitation of patients. Since standard management is less time consuming it is more cost efficient. These conclusions are relevant to a service for which there is a high requirement and low provision in the United Kingdom