Landscape scale planning for batsProf. Fiona MathewsUniversity of Sussex

f.mathews@sussex.ac.uk @MathewsFionaf.mathews@sussex.ac.uk @MathewsFiona

Since 1970

41%

33%

26%

Populations

27%

52%

21%

Distributions

0.5M new houses pa

1,600 mi new roads 2006-1850% increase in traffic by 2050

1% increase pa

What does strategic planning for bats look like?

Razgour et al. 2013

Habitat suitability modelling:

• Presence only data c.f. pseudo-absences• Predictors usually climate and land cover• Predicts PRESENCE = DISTRIBUTION• Does NOT predict density/popn size

P Wright, PhD thesis 2018

2,877 initial presence records 620

50 maternity colonies records, 84 males in hand, 486 other

HSM map from all data

Best modelAll

records

Male

records

Maternity roost

recordsAUC (higher=better) 0.88 0.92 0.83Contribution (%):Distance from woodlands 50.1 66.3 28.8Distance from ancient

woodland16.6 NA NA

Woodland type 15.2 NA 40.8Elevation 12.7 16.8 14.6Ancient woodland 3.2 NA NALand cover 2.2 9.6 15.8Distance from urban area NA 7.3 NA

What is the question?

Different filters=different maps

n=283 in hand records

• Record reliability?• Are records a random sample of population?• Where are the ‘pseudoabsences’? Tautology?• Always prefer analysis of surveyed absences• Beware widespread generalist and cryptic species

Areas of high POTENTIAL suitability may be INACCESSIBLE

Analyse movement and/or gene flow

Light Light

Habitat Habitat

RASTERS RESISTANCE LAYERS

Multivariate

0

500

1000

1500

2000

2500

3000

3500

<=25% 26-50% 51-75% >75

Pass

rat

e

Circuitscape current

Umbrella species?

Gene flow

High habitat suitability and low resistance

Accounting for constraints within the local plan

Add in weights for:• Conflicting land-use type• Future constraints• Improvement potential

Summary:

• HSMs useful for DISTRIBUTION not density• Consider connectivity• Be open minded about ‘value’ of habitats• Think about context and cumulative impacts• Share data

@MathewsFiona