watershrew’s and wetland habitat quality dawn scott & fran southgate
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Watershrew’s and wetland habitat quality
Dawn Scott & Fran Southgate
University of BrightonUniversity of BrightonUniversity of Brighton
Project background
• 2002-2005• Partnership – SROP & UOB• MPhil – Fran Southgate• 27 study sites over 3 catchments• Cuckmere, Ouse and Pevensey
Levels• Monitoring: Summer and Winter
for 3 years
What is a water shrew?•Noemys fodiens
•Largest UK shrew: 13g•Dark, usually silver pale underside • Fringed tail and feet
Ecology: Breeding peak May & June (2 or < litters/season)
Life span 14-19 months
Aquatic/Riparian (but can be found away from water)
Insectivore: Diet 50: 50 terrestrial/aquatic invertebrates
Why focus on this species?
• Limited data on habitat requirements and distribution
• Conservation status? W&C act 1987
• Predominantly feeds on aquatic prey
• Intolerant to poor water quality ???
• Potential bio-indicator of water quality ??
Project aims
• Assess presence & abundance of water shrews across the 3 catchments and monitor these seasonally
• Assess habitat characteristics and habitat quality
• Assess presence and abundance of invertebrate prey base
• Record indicators of water quality
Methods• Shrew scat tubes:P/A and relative abundance • Wetland features: Bank slope, water body
• Plant diversity: Bank and in-stream
• Water quality:Temp,DO, pH, NH4, P, N
• Habitat assessment:Composition and structure
• Invertebrates:Diversity, BMWP, ASPT
Chart showing overall relative abundance - Pevensey catchmnent
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PMW PREA PNB POPC PHB PPW PBF PNS PHG
Site
Rel
ativ
e ab
unda
nce
Win 04
Sum 04
Win 03
Sum 03
Habitat Variable Ws relative abundance
rs P
Herb forb % cover -0.236 0.038
Grass % cover 0.044 0.700
Sedge % cover 0.230 0.038
Reed % cover 0.240 0.034
Litter % cover 0.215 0.058
Bare ground % cover 0.102 0.376
Shrub % cover 0.008 0.943
Rush % cover -0.004 0.969
Grass height (m) 0.257 0.023
Litter height (m) -0.013 0.910
Us/ds % tree cover -0.145 0.205
Us/ds % shrub cover -0.071 0.534
Us/ds tree density -0.100 0.385
Us/ds shrub density -0.032 0.781
Water parameters
• PH, temp. & DO showed no significant effect on water shrew presence over all sample seasons
• Only DO in summer ’03 showed a significant effect on water shrew presence where higher DO = higher abundance
• Higher water temperature was associated with lower water shrew presence in Summer 03 and Winter 04
• Data for phosphate, nitrates and ammonia showed no statistically significant relationships with water shrew abundance
Invertebrates
• Positive correlations between invertebrate diversity and richness scores and seasonal water shrew relative abundance in Summer 03, Winter 03 and Summer 04
• However, statistical analysis confirmed that neither water shrew presence nor relative abundance were associated with any of the derived BMWP and ASPT scores.
Family Common Name U value P Value
Calopterigidae (unknown) Damselfly larvae 844.5 0.002
Chironomidae Biting Midge larvae 986.0 0.011
Ecdyonuridae Flattened mayfly nymph 1020.0 0.038
Hydrobiidae (2) Snail 968.0 0.019
Hydrobiidae (3) Snail 986.0 0.011
Leptoceridae Caddis 917.5 0.037
Lymnaeidae Pond snail 1020.0 0.038
Mollannidae (1) Caddis 986.0 0.011
Philopotamidae Caddis 986.0 0.011
Physidae Aquatic snail 769.5 0.011
Polycentopaidae Caddis 1100.5 0.037
Coleoptera (Unidentified) Water beetle 1020.0 0.038
Tricoptera (unknown) Caddis 1100.5 0.037
Ephemoptera (Unidentified) Mayfly nymph 244.0 0.032
Hydracarina Water flea 218.0 0.049