1. Postgraduate Workshop 2014 Spatial Analysis for Landscape Ecologists
When is it worth manipulating and creating your own data?
Jess Neumann

2. Introduction Lots of different sources of data
They all contain topological or spatial errors to some degree
What’s your question / aim / hypothesis?
What data might help you with that?
How accurate do you want / need the data to be?
How much time do you have?

3. Introduction 3 main options: Use the data as it comes
Manipulate the datasets which exist
Create your own new data
The first option is the easiest (and most readily adopted)
The last is potentially the most time consuming and should only be undertaken if you are sure there is no other way!
Personal experience; I shall explain why.

4. My Research
How biodiversity responds to landcover composition and landscape structure in the wooded-agricultural environment of southern Britain
Contemporary landscapes
Historic landscapes
Species distribution patterns
Species movement and dispersal
Identification of key landscape elements
To help inform farm-scale conservation efforts

5. Project 1:
How do different beetle species respond to the contemporary landscape?
Can we identify key landscape elements for conservation?

6. Project 1:
Compositionally similar; structurally different configurations

7. My data options… To map the current landscape I needed the following:
Topographic data (slope, elevation, aspect)
OS Digital Terrain Models
Contemporary landcover data
LCM2007; OS MasterMap; Satellite imagery; Digitise it myself

8. The Challenge… LCM2007, OS MASTERMAP LCM2007 & OS MASTERMAP LCM2007
& HEDGEROWS
LCM2007 & OS MASTERMAP

9. My data decision… Contemporary landcover data
LCM2007 Easily accessible, definitive UK coverage, accepted method Topological inaccuracies, lacking local-scale detail
OS MasterMap Great local scale detail, topologically and spatially accurate Accessible… but needs converting Data heavy (small areas only), no landcover information
Satellite imagery
Was a no go for me!
Digitise it myself Great spatial and topological information (i.e. hedgerows) Very time-consuming

10. Manipulating data Combination method
Use MasterMap data for topological accuracy; reclassify

11. Manipulating data

12. Manipulating data
Take the LCM2007 data and classify using Broad Habitats
Clip LCM2007 data by accurate polygons of MasterMap data

13. Manipulating data

14. Creating new data Still missing some vital landcover information
Hedgerows and linear features are an integral part of the British landscape (and many areas of Europe too)
Key connecting features – green corridors
Few landscape studies include any linear detail
Or classify them all as one ‘type’ of feature

15. Contemporary landcover

16. Creating new data Digitised hedgerow data does not exist
Tried using satellite imagery…
Decided to digitise by hand using Google Maps aerial imagery

17. Creating new data 7 categories of hedgerow 36 2 x 2 km tetrads in 2011
2 – 3 hours per tetrad
Some 4 – 5 hours
119 tetrads by 2014
= 300+ hours of digitising

18. Was it worth it?
Combining and manipulating pre-existing landcover data
YES DEFINITELY High quality landcover data for not much effort
Creating new hedgerow data
YES… Significantly important landscape elements for biodiversity Opportunity to validate landcover classifications
…BUT I probably would not have done it in hindsight if I knew how many tetrads I would have to do
Do we always need to alter or create data?

19. Project 2:
How have beetle communities responded to land-use change in agricultural environments in the UK?
What does this mean for conservation and future species survival?
Required a comparison between contemporary and historic landscapes
Contemporary – same data options as previously
Historic – Dudley Stamps maps (Land Utilisation Survey of Great Britain 1933 – 1949)

20. Historic data First land-utilisation survey of GB early 1930’s
Dudley Stamp Maps one-inch-to-the-mile
Digitised in 2011 by DEFRA and Env. Agency
7 Broad Habitat types – simple polygons

21. Contemporary Data
Classified LCM2007 into Broad Habitats comparable with Dudley Stamp maps

22. Project 2 results Widespread landscape change
Today’s beetle communities respond more strongly to historic landscape conditions
Large-bodied, flightless, woodland species respond to historic but not contemporary woodland cover
These same species correlated with woody-hedgerows (for long-term dispersal) in the contemporary analysis
Relative rates of change: Grasslands: – 91 % Lowland heath: – 95 % Dec. woodland: – 6 % Agricultural land: % Total woodland: + 7 %

23. Hedgerows? Hedgerows digitised for contemporary landscape only
Would have to obtain historic aerial photographs for each site and digitise Access, Money & Time key limitations
Hedgerows were proven to be an integral landscape component in modern landscape analyses
But some good results are achievable without having this extra data in the historic analyses
So, is it worth it?

24. Summary
Using data ‘as it comes’ is great but be aware of inaccuracies and the potential effects it could have on your results
Manipulating or creating new data is not free from errors
Combining and reclassifying data is relatively easy but consider: Size of your study sites Requirement for higher-quality data Time limitations
Creating new data Very time consuming at the landscape scale A last resort?