Ian Thornhill

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Spatial analysis and remote sensing

Since 2002 I have used geographical information systems (GIS) for a variety of different outputs and analyses equating to over ten years of experience. Outputs have spanned from simple plotting of habitat cover resulting from, for example, Phase 1 habitat surveys and plotting of point data e.g. evidence of water vole presence, to the formation of resistance maps to inform least-cost-path (LCP) analysis and/or circuit theory using composite raster surfaces of remotely sensed information and land cover. In order to carry out these work-streams I have, at one time or another, used ArcGIS 3.2, 9.2, 9.3 and 10, plus extensions e.g. Hawth’s Tools, and in recent times have switched to the open source applications Quantum GIS and GRASS and associated plugins. Some selected projects for which I have used GIS are:

Historical habitat loss and habitat connectivity

Using historical maps ca.1904 ‘County series’ and ca.1962 ‘National Grid’ series I digitised (ArcScan) the development of the contemporary (2009) pond habitat network and overall habitat loss. Using network theory (graph theory) I assessed the impact of habitat loss upon the spatial configuration and connectivity of the network over time and identified priority habitats for the maintenance of connectivity and potential ecological flux.

Northumbria Water; preparation for the Water Framework Directive (Cascade Consulting)

Using EA regular monitoring data combined with GIS we assessed the potential failings of rivers within Northumbria against Water Framework Directive requirements and highlighted possible point and diffuse pollution sources

The effect of land-use and habitat availability upon macroinvertebrate community composition

I used a suite of spatial datasets including MasterMap data (OS), Landcover Map 2007 (CEH), photogrammetrically derived height and Normalised Difference Vegetation Index (NDVI) in a series of multivariate analyses across different spatial scales in order to their influence upon the water quality and biodiversity within urban ponds


GIS (network theory) and remote sensing

Aquatic biological sampling and identification

I was taught aquatic biology sampling methods formally as part of an M.Sc in Pollution and Environmental Control at the University of Manchester in 2005. I have since applied this knowledge to the biological assessment of both rivers and still waters. I am familiar with standard biological assessment methods such as RIVPACS (three-minute sampling) and Biological Monitoring Working Party (BMWP) scoring. In recent years I have undertaken sampling of 30 ponds as part of my doctoral study (employing a method based upon those of the National Pond Survey) and have demonstrated kick-sampling methods to numerous undergraduate students. Previously, I interpreted Environment Agency biological data to indicate the potential effects of changes in flow upon macroinvertebrate communities using the Lotic Invertebrate index for Flow Evaluation (LIFE) and also to assess for the presence of non-native species. I have amassed many hours of laboratory time identifying both riverine and still water macroinvertebrates to species level.

Water quality analysis and interpretation

As a doctoral student I have undertaken extensive in situ and laboratory based water quality analysis for:

  • The determination of major anions (chloride, nitrate, sulphate and phosphate) and cations (sodium, ammonia, potassium, magnesium and calcium) using ion chromatography and photometry methods
  • The determination of trace metals e.g. iron, manganese, zinc, copper, chromium, using atomic absorption spectrometry methods
  • The determination of suspended solids and chlorophyll abundance (a, b and c) using acetone abstraction and spectrophotometry
  • The application of excitation emission matrix fluorescence spectroscopy (EEMs) in order to assess organic matter content
  • Basic in situ measurements of dissolved oxygen, pH, temperature and conductivity.

Non-native species

Non-native, ‘exotic’ or ‘alien’ species have been a personal interest since undertaking an undergraduate project investigating the presence and impact of non-native species upon semi-natural ancient woodlands in 2005. I am particularly interested in how non-native species interact within natural communities, their role as potential substitutes for the loss of native species and people’s perception of non-natives, particularly supposed charismatic species e.g. ring-necked parakeets. Here are some selected projects involving non-native species:

Non-native species surveys (Cascade Consulting)

I undertook non-native species surveys as part of pre-development planning for private developers. Typically, this was restricted to Japanese knotweed (Fallopia japonica) due to the financial cost of disposal. Survey results were digitised in GIS to aid plant removal and recommendations for management made.

Non-native aquatic plants

I undertook macrophyte surveys as part of the doctoral study of urban ponds. As an urban habitat, non-native macrophyte species were frequently encountered including, but not limited to, New-Zealand pygmyweed (Crassula helmsii), parrot’s feather (Myriophylum aquaticum) and floating pennywort (Hydrocotyle ranunculoides). Aquatic invasive plant species are also recorded as part of River Habitat Surveys (RHS), for which I have assisted on numerous occasions.

Non-native aquatic fauna

I carried out an assessment of non-native aquatic species (macroinvertebrates and vertebrates) presence in response to proposals for a proposed large reservoir project and applied expert knowledge to hypothesize their potential spread as a consequence of its construction and operation. In order to do this I incorporated records from the local biological records centre, RHS survey data, EA biological monitoring data and sub-contractor survey results.

During my doctoral study I assessed ecosystem functioning using a leaf decomposition experiment. I found that a pollution tollerant, non-native species may be playing a compensatory functional role following the removal of a native species more sensitive to pollution.

Protected species

I have undertaken surveys for the presence of water vole (Arvicola amphibious) and reptiles e.g. Slow worm (Anguila fragilis) and grass snake (Natrix natrix) and have a good knowledge of great-crested newt ecology. However, whilst this is an area in which I am a competent, I do not yet hold any UK protected species license.

Statistical analysis and data handling

I have undertaken a number of statistical analyses using water quality data from a variety of sources (EA, sub-contractors, personal collections). I have good knowledge of a range of statistical software including R, SPSS, MiniTab and CANOCO. I also have an excellent knowledge of Microsoft Excel and in each case I am used to handling large spatial datasets.



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