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Using GIS technologies to visualise wildlife population changes

The middle of November sees a day to celebrate the use and implementation of GIS and similar technologies. Instead of our usual content of business efficiency and analysis we thought we could illustrate the use of GIS for ecological and wildlife studies.

An otter

Mapping otter sightings

A search online produced data looking at otter sightings in England from the late 1970’s to the early 2000’s. The data meant we could draw some illustrative maps for otter sightings across the country. The dataset had a record of the date of sighting and location in latitude and longitude. To keep sighting locations secure the coordinates are rounded somewhat.

The point of the exercise was to illustrate the changes in otter distributions over a longer period. It shows that our mapping system can import, analyse and display data with postcode, british national grid and latitude longitude location data.

The summary of the sightings is not too helpful, otters are spread across much of England and there are more of them in the wilder more remote areas.

Splitting the data out into time bands meant we could produce some longitudinal maps that showed how the otter ranges expanded over the last years of the 20th century. The data has not been evenly spread across the whole survey period from 1977 to 2001. The ranges work out as 1977 to 1985, 1986 to 1995, and after 1996. The record counts are interesting: 1977 to 1985 has 288 records, 1986 to 1995 has 872 records, and after 1996 has 1137.

Map showing a distribution of otter sightings across England from 1977 to 2001.
Otter sightings up to 1985
Sighting locations up to 1985, the South West and Welsh Marches indicate the largest ranges.
Otter sightings up to 1996
Sightings up to 1996. Ranges have expanded North and East from their earlier ranges. New river basins have sightings and the existing ranges seem to be busier.
Otter sightings after 1996
Sightings after 1996. Otters are seen in new areas, existing areas have more sightings and we can infer the population and range increased in the years from the late 70’s to the early 2000’s.

Without the spatial analysis the picture would be much harder to recognise.

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