Four Rodent and Vole Biodiversity Models for Europe

Species Striped Field Mouse, Apodemus agrarius; Yellow-necked Mouse, Apodemus flavicollis; Broad-toothed Field Mouse, Apodemus mystacinus; Wood Mouse, Apodemus sylvatica; Bank vole, Clethrionomys glariolus; Common vole, Microtus arvalis; European pine vole, Microtus subterraneus; Norway rat, Rattus norvegicus; Black Rat, Rattus rattus; Common Shrew, Sorex araneus; Eurasian Pygmy Shrew, Sorex minutus (2) Methods

• The rodent distribution layers that were modelled models were complied from several sources as follows: • The EMMA Database 2 : Mapping Europe's mammals using data from the Atlas of European Mammals.• IUCN Red List Dataset 3 • The National Biodiversity Network 4 UK 10k Data-Making all biological records freely and easily available to everyone • Globcover 2009 Land cover map 5 Four biodiversity indices -the number of species recorded at a single location -were defined according to different species lists suggested by various experts identified in the Acknowledgements section.The species for each index are identified in Table 1.

Four Rodent and Vole Biodiversity Models for Europe
William Wint 1 , David Morley 2 , Neil S. Alexander  The mechanisms underlying associations between rodent diversity and the spread of rodent borne diseases are still unclear.The number of potential host species may influence a disease by either spreading the pathogen (or vectors) more rapidly or conversely by reducing contact with other hosts through the effects of dilution.In either case the number of potential hosts may impact on the distribution of a disease or its vectors.Four spatially modelled indices of rodent species richness have been generated to support distribution modelling of rodent borne diseases specifically initially focussing on Hantaviruses and tick borne diseases.

Rattus rattus X
Sorex araneus X X

Sorex minutus X
Table 1: Species included in each index are marked with an "X".For more details please see the supporting document (edenextvolelayers.docx)within the data download.
The spatial modelling also requires a comprehensive predictor variable suite which included a wide range of remotely sensed variables as follows: 1  12 The four different rodent biodiversity index layers were modelled using a range of techniques: 1. zoned random forest 14 method calculated via the VECMAP 15 modelling system using a point input dataset 2. zoned bootstrapped General Linear Model (GLM) 16 method calculated via VECMAP 15 modelling system using a point input dataset 3. zoned regression calculated using the FARMS 17 modelling suite using an polygon input dataset An ensemble mean was taken of the three model outputs for each Biodiversity variable.

Output Datasets
Each of the four Biodiversity indices has been provided as a quick look map in JPEG format to view from any image viewer.The data itself is distributed as GIS Raster data in two formats.GeoTIFFs which is a standard proprietary GIS raster format.GeoJP2 (JPEG 2000 format) which is a nonproprietary format.Please note that as the GeoJP2 format is an integer-only format, the values found in this format have been multiplied by 100 to minimise the loss of data.
To access and analyse the Raster data directly GeoTIFFs and GeoJPGs can be read by most GIS software and some other software packages These formats are compatible with proprietary (ESRI ArcGIS) and open source (Quantum GIS (QGIS) or R-project raster package) Sample points were extracted for input into the three different models from a 20km matrix defining the number of key rodent species for each index (as defined in table 1).Depending on the model 1000-2000 sample points were used in each of 25 bootstraps.

Quality Control
These models are a first attempt at quantifying the rodent biodiversity at this scale and there has been no ground truth validation of these maps so far.The model outputs all, however, satisfy standard accuracy metrics (AIC, R squared and Kappa statistic) assuring statistical reliability.They have also been informally reviewed by project Rodent-Borne disease experts.

Constraints
There were no constraints involved in data production.

OPEN ACCESS (4) Reuse potential
The subject of the effect of rodent biodiversity upon the spread of vector-borne disease is a fairly new topic.These layers are a first attempt to provide a description of rodent biodiversity at a continental scale.They have been developed in the hope they will aid epidemiologists test hypotheses relating to the role of rodent biodiversity' in the spread of infectious disease.Areas of future development on the dataset itself might be to: assess the accuracy of the maps through ground-truthing; a comparison of the three different models used in this analysis and an assessment of which model provides the most accurate outputs; the application of this approach to different groups of species thought to be related to the spread of different diseases.
data, Processed data, Interpretation of data.