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Graham Earl & Tom Dargie: Part 1 Interpreting sand dune habitat change at Sandwich Bay using sequential NVC survey Dr Tom Dargie – Boreas Ecology Sandwich.

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Presentation on theme: "Graham Earl & Tom Dargie: Part 1 Interpreting sand dune habitat change at Sandwich Bay using sequential NVC survey Dr Tom Dargie – Boreas Ecology Sandwich."— Presentation transcript:

1 Graham Earl & Tom Dargie: Part 1 Interpreting sand dune habitat change at Sandwich Bay using sequential NVC survey Dr Tom Dargie – Boreas Ecology Sandwich Bay Estate Deal Royal Cinque Ports Golf Course Bird Observatory Royal St George’s Golf Course Princes Golf Course Nature Reserve Nature Reserve © Google Earth 1.Context: primary slacks, adjacent effects 2.NVC mapping: 1989, 2001, Changes in habitat extent 4.Directions of habitat change 5.Quadrat analysis of change Himantoglossum hircinicum Lizard Orchid Ellenberg F = 3 Ellenberg N = 2 Orobanche caryophyllacea Clove-scented Broomrape Ellenberg F = 3 Ellenberg N = 2

2 NVC Mapping: Initial Survey 1989 (Sand Dune Vegetation Survey of Great Britain) (Doarks, Hedley, Radley & Woolven (1990) NCC CSD Report No. 1126) Digitised version of 1989 map used in Dargie (2002)

3 NVC Mapping and Mapping Change: Follow-up Survey (2001) (T. Dargie (2002) Sandwich Bay Dunes, Kent: NVC Survey Unpublished Report to English Nature (Kent Team))

4 NVC Mapping and Mapping Change: Third Survey (2008) Royal St George’s Golf Club (T. Dargie (2009) National Vegetation Classification (NVC) survey of sand dunes at Sandwich Bay, Kent: 2008 Repeat NVC Survey of Royal St. George’s Golf Club. Unpublished Report to Natural England. NE Contract 6/NE/0126)

5 Sandwich Bay Habitat Extents

6 Royal St George’s GC Habitat Extents 1989 –

7 Main Pathways of Change (hectares) mainly SD8 Festuca rubra - Galium verum mainly MG1 Arrhenatherum elatius mainly MG12 slack Schedonorus arundinaceus (Festuca arundinacea) 7 SB 1989 to 2001 RSG 2001 to in cattle grazing enclosure

8 Quadrat Analysis Step 1 Pseudo-random quadrat (‘pseudoquadrat’) approach Rhind et al. (2006) Proc. Royal Irish Academy 106B first applied it to dune habitat Simulates species data for 25 quadrats per NVC sub-community based on (i) Published range in Domin scores (ii) Published constancy (frequency) class (ranging from I to V) (iii) Published range and average number of species per quadrat Dr Roy Sanderson (Newcastle) supplied pseudoquadrat data for dune NVC types Step 2 Ellenberg Scores Gradient Analysis Calculate F Moisture and N Nitrogen for pseudoquadrats and RSG quadrats Calculate mean and standard deviation for F and N per NVC (sub)community Graph probability ellipses (3 SD widths) for NVC communities on F & N axes Graph individual quadrat positions, colour coded by year

9 Ellenberg Gradient Analysis: Pseudoquadrat Probability Ellipses

10 Ellenberg Gradient Analysis: Royal St George’s Golf Course Quadrats

11 Conclusions GIS evidence suggests that SD8 fixed dune grassland is changing quite rapidly to MG1 and MG12 Quadrat change analysis suggests the same (Repeat analysis of target notes shows the same) The future for key Red Data Book species at this site seems threatened by hydroecological change 

12 Hydro-ecological Investigation of Habitat Change: Based on Sandwich Bay Sand Dunes, Kent Interpreting sand dune habitat change at Sandwich Bay using sequential NVC surveys and hydrological analysis Graham C J Earl Coastal Eco-hydrological Researcher Canterbury Christ Church University

13 My research is investigating research recommended in the Dargie (2009) report: The possible interactions of physicochemical values within the groundwater; The interactions between vegetation communities and nutrient levels; The possible influences from golf course management; A possible long-term increase in the water table, possibly driven by sea-level rise. The focus of this presentation: – The relationship between hydrological dynamics, physicochemical factors and overlying sand dune vegetation. Overview of Research

14 Dipwell Positions Across Sandwich Bay Dipwells chosen using Judgement Quota sampling; Two tier approach, using historic data and ground truthing; Locations limited by access and position of water table.

15 Sampling Schematic Dipwell Elevation obtained from LiDAR data, adjusted to OS Newlyn datum

16 Water samples collected monthly June 2012 – November 2012, with a further collection quarterly from March 2013 – June 2014, and analysed for: – Sodium (NaCl) – Potassium (KCl) – Total oxidised nitrogen (TON; NO2 + NO3) – Phosphate (P) – Ammonia (NH3) – pH – Electrical conductivity (EC) Chemical Analysis

17 Observed Total Oxidised Nitrogen Concentration Summer 2012 Winter 2012 Autumn 2012 Spring 2013

18 Observed Ammonia Concentration Summer 2012 Autumn 2012 Spring 2013 Winter 2012

19 Observed Phosphate Concentration Summer 2012 Winter 2012 Autumn 2012 Spring 2013

20 There is no significant difference in nutrient concentrations between vegetation communities; – Preliminary results using a nonparametric Kruskal-Wallis test, on chemical values comparing between different NVC classes near dipwells; Note: data collection is on going until June 2014, thus analysis is currently on an incomplete data set. Null Hypotheses Summer 2012 Phosphate vs NVC P = Summer 2012 TON vs NVC P = Summer 2012 NH NVC P = Summer 2012 KCl vs NVC P = Summer 2012 NaCl vs NVC P = Spring 2013 Phosphate vs NVC P = Spring 2013 TON vs NVC P = Spring 2013 NH3 vs NVC P = Summer 2013 KCl vs NVC (Not Available) Summer 2013 NaCl vs NVC (Not Available) Summer 2012Summer 2013 NaClP = 0.415P = KClP = 0.032P = PO4P = 0.797P = TONP = 0.055P = NH3P = 0.456P = 0.141

21 Historic Weather Dynamics and NVC Communities Surveyed Years

22 Historic Weather Dynamics and NVC Communities

23 Observed Water Table Levels Autumn 2012 Spring 2013 Summer 2012 Winter 2012

24 There is no significant difference between ground elevation and vegetation community cover; – Nonparametric test Kruskal-Wallis, on LiDAR elevation data comparing between different NVC classes near dipwells; Adjusted data to ensure samples with ≥3 replicates were analysed. Null Hypotheses 2012 NVC Cover P = NVC Cover P = NVC Cover P = NVC Cover P = 0.038

25 Data collection on-going (20 months out of a 24 month sample period has been collected); Only simple non-parametric methods have been applied so far in data analysis, multivariate analysis will be run on a complete data set; Repeat survey of tidal fluctuation effects on the water table height. Summary

26 Funding support: RCPGC and Natural England; Access permission and other support: RCPGC, RSGGC, Princes GC, Alan Husk, and Sandwich Bay Residents; Help in the field in sometimes poor conditions, plus research advice (the sun does not always shine over Sandwich!): Phil Buckley, Phil Williams, David Ponsonby, Alex Kent, John Hills (CCCU), Phil Williams (Natural England), Tom Dargie (Boreas Ecology), Students at CCCU, Friends and Family. Acknowledgements

27 Thank you for listening Questions Welcome Contact:


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