PhD by: Niels Brouwers (Bournemouth University)
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School of Conservation Scienc Analyses of the spatial distribution of wood cricket (Nemobius sylvestris) on the Isle of Wight (UK) PhD by: Niels Brouwers (Bournemouth University) Supervised by: Dr. Adrian Newton (Bournemouth University) Dr. Sallie Bailey (Forestry Commission) Dr. Kevin Watts (Forest Research)
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Analyses of the spatial distribution of wood cricket (Nemobius sylvestris) on the Isle of Wight (UK). PhD by: Niels Brouwers (Bournemouth University) Supervised by: Dr. Adrian Newton (Bournemouth University) Dr. Sallie Bailey (Forestry Commission) - PowerPoint PPT Presentation
Transcript of PhD by: Niels Brouwers (Bournemouth University)
School of Conservation Sciences
Analyses of the spatial distribution of wood cricket (Nemobius sylvestris) on
the Isle of Wight (UK)
PhD by: Niels Brouwers (Bournemouth University)Supervised by: Dr. Adrian Newton (Bournemouth University)
Dr. Sallie Bailey (Forestry Commission)Dr. Kevin Watts (Forest Research)
School of Conservation Sciences
Index
• Introduction• Objective• Research Questions• Study Area• Method• Results• Discussion
School of Conservation Sciences
Introduction
• Background– Woodland conservation– Restoration and expansion– Forest Habitat Networks
School of Conservation Sciences
Objective
• To determine what factors influence wood cricket (Nemobius sylvestris) distribution on a landscape and local scale.
1 cm
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Research Questions:
• Where is wood cricket situated on the Isle of Wight?
• Is wood cricket presence related to the factors: woodland type, age, area, shape and nearest neighbour distance?
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Study Area
Surface Area: 381 km²
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Method
• Summer 2005
(Mid-July/Mid-September)• Walk survey• Woodlands
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13%46%
Results: Distribution
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Broadleaved Coniferous Mixed
Woodland type
0
20
40
60
80
100
Pe
rce
nta
ge
of
wo
od
lan
ds
(%
)
Results: Woodland Type
• Pearson Chi-Square: χ² = 1.146, n = 215, P = 0.564
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Secondary Ancient
Woodland age
0
20
40
60
80
100
Pe
rce
nta
ge
of
wo
od
lan
ds
(%
)
Results: Woodland Age
• Pearson Chi-Square: χ² = 4.585, n = 144, P = 0.032
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Present Not present
Wood cricket presence
0
10
20
30
40
50
60
Wo
od
lan
d a
rea
(h
a)
a
b
Results: Woodland Area
• Mann-Whitney test, Z = -3.175, n = 215, P = 0.001
vs.
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Results: Woodland Shape
• Mann-Whitney test: Z = -3.254, n = 215, P = 0.001
Present Not present
Wood cricket presence
1.0
2.0
3.0
4.0
5.0
Sh
ap
e i
nd
ex
72
75
a
b
vs.
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Results: N. N. Distance
• Mann-Whitney test: Z = -6.478, n = 215, P = 0.000
0
5
10
15
20
25
30
35
100
200
300
400
500
750
1000
1500
2000
2500
3000
4500
6000
6500
Distance (m)
Pe
rce
nta
ge
of
wo
od
lan
ds
(%
)
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Results: Logistic Regression
Variables Wald df Significance (P) R² adjusted
Area 3.158 1 0.076 n.s. 0.037
Shape 10.003 1 0.002 0.072
Distance 18.100 1 0.000 0.291
Logistic regression models
Distance + Area 16.086 1 0.000 0.380
Distance + Shape 11.181 1 0.001 0.367
Distance + Area + Shape 4.305 2 0.038 0.404
Spearman rank correlation:_____________________________________Area vs. Shape: r = 0.604, P = 0.000Area vs. Distance: r = 0.139, P = 0.041Distance vs. Shape: r = 0.098, P = 0.153
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Discussion
• Summary: – Type (ns)– Age (s)– Area (s)– Shape (s)– N. N. Distance (s)
– Logistic regression
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Discussion
• Distance and Area– Unexplained variation– Habitat variables
• Conservation effort– Landscape scale planning– Target
• Large fragments • Aggregations
better than
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Thank you for your attention
