Species Richness

Butterfly species richness map
Project Summary

 

Mapping biological records is in the blood of the ERCCIS team and a core part of what we do. But it can be difficult to understand by looking at these raw records. Interpretation and analysis is needed to make sense of these records and effectively inform conservation effort. 

To help interpret biological records we host, ERCCIS has developed species richness maps which are freely and publicly available online to everyone. Understanding species richness helps to build a picture of the stability and characteristics of the landscape when taken into account. Species richness is important for conservation to help understand the ecological characteristics of our landscape and where there are high and low levels of species richness. If an area has a higher species richness it is considered as a more stable ecosystem.

 

What is species richness?

Species richness is a count of different species within an ecological community, landscape or defined region. Understanding species richness helps to build a picture of the stability and characteristics of the landscape when taken into account among other parameters. Species richness is important for conservation to help understand the ecological characteristics of our landscape and where there are high and low levels of species richness. If an area has a higher species richness it is considered as a more stable ecosystem.  Creating maps of species richness adds to the resources and tools available to help inform effective conservation efforts across Cornwall. 

 

Explore the story of our Species Richness Mapping

 

 

Explore the ERCCIS Species Richness maps for Cornwall

 

 

 

ERCCIS species maps have been funded by TEVI and are publically available to explore online. 

 

Request Species Richness maps

Are you interested in requesting species richness maps for your area or species group of interest. Please contact us with your details. 

 

The technical information

 

What information did we use?

ERCCIS has modelled species richness for 9 taxon groups, which were selected based on number of biological records available and to represent a broad spectrum of the ecology of Cornwall. Records were limited to taxon groups considered primarily representative of the terrestrial environment as a representation of the process.

Taxon Group

Number of Records

% of total hosted records

flowering plant

1866796

27.9%

bird

1814710

27.1%

insect - moth

1271327

19.0%

insect - butterfly

305222

4.6%

fungus

111217

1.7%

terrestrial mammal

76196

1.1%

Records considered incorrect or invalid were excluded from the datasets for each taxon group. The records were limited to a 20 year timeframe, between 1999 and 2019 to best represent the current state of the ecosystems in Cornwall. Biological records which were recorded at tetrad or better resolution were used to ensure a high number of input records were available for each taxon group as well as giving an acceptable resolution output with each grid cell covering 22km of Cornwall’s landscape.

 

The Methods explored

Three processes were investigated to produce species richness maps for Cornwall using biological records hosted by ERCCIS;

  1. ERCCIS Method - Count of records per tetrad covering the terrestrial area of Cornwall, processed through SQL script developed by ERCCIS

  2. FSC Method - Using QGIS prebuilt processes from external bodies, in this case the Field Studies Council TomBio QGIS tools (www.fscbiodiversity.uk/qgisplugin/v2)

  3. Frescalo Method - Using R script developed by the Centre for Ecology and Hydrology called Frescalo which corrects for variations in recorder effort through neighbourhood statistics. (https://www.brc.ac.uk/biblio/frescalo-computer-program-analyse-your-biological-records) . More information about the Frescalo analysis principals can be found in Hill 2011 (https://doi.org/10.1111/j.2041-210X.2011.00146.x)

 

The ERCCIS TomBio and Model

If we do a simple count of species recorded at a small site, we could reasonably record all species within the site but this becomes nearly impossible when we try and consider an entire county. If we were to do a simple count of different species from biological records we start to encounter bias caused by the nature of biological recording. The difficultly with calculating species richness from biological records is variations it the spatial and temporal coverage of biological records and recording effort involved in collecting the records.

This is where statistical modelling comes into play. We’ve used a well-respected and published method developed by Biological Records Centre (BRC) which corrects for variations in recorder effort

 

Frescalo Model

The CEH Frescalo analysis estimates species richness from biological records where recorder effort is uneven. The model uses neighbourhoods based on proximity and habitat similarity across the study area and calculates the mean weighting for sampling/recorder effort for each neighbourhood based on the records for commonest species, i.e. if a high proportion of the commonest species in a neighbourhood have been recorded, then the neighbourhood is considered well recorded. This weighting is used to re-scale observed species frequency/species richness to give estimate species frequency/species richness and so corrects for o uneven sampling/recorder effort.

For more detail on the model see;

Hill, M.H. (2011) Local frequency as a key to interpreting species occurrence data when recording effort is not known. Methods in Ecology & Evolution, 3 (1), 195-205. http://www.respond2articles.com/MEE

Details of our model - the perimeters and weighting for neighbourhood (200,100) creation and the sampling‐effort multiplier (0.74) were based on the default settings outlined in Hill, 2011 for each taxon group.  The estimated species richness after rescaling was used for producing the output species richness maps.