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LESSONS LEARNT FOR HARVESTING SEED IN BIODIVERSITY MITIGATION AND ENHANCEMENT SCHEMES IN THE UK. Professor R Neil Humphries CSci CBiol BSc MA PhD MBS MIPSS FIQ Sustainable Reclamation ASMR National Meeting, Tupelo, Ms. June 8th-15th, 2012. Background . - PowerPoint PPT Presentation
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LESSONS LEARNT FOR HARVESTING SEED IN BIODIVERSITY MITIGATION AND ENHANCEMENT SCHEMES IN
THE UKProfessor R Neil Humphries CSci CBiol BSc MA PhD MBS MIPSS FIQ
Sustainable ReclamationASMR National Meeting, Tupelo, Ms. June 8th-15th, 2012
Objective - to understand more about seed collection from natural sources
Study undertaken in 1992 & 1993 5 coalfield grassland – mire/fen meadow
sites in South Wales, UK, harvested early & late July
All UK Biodiversity Action Plan grasslands (NVC mesotrophic grasslands MG5 & MG8; mires M23, M24 & M25; acid grassland U5)
Emorsgate tractor-drawn suction harvester Seed was air-dried, sieved & bagged
Background
1. Donor site species composition and their flower & seed development stages
2. Species composition of harvested seed
3. Efficacy of suction harvester 4. ‘Harvestability’ of seed
Four Studies Undertaken
Seed Harvesting
MG5 Cynosurus cristatus – Centaurea nigra meadow
M23 Juncus effusus – Juncus acutiflorus – Galium palustre rush pasture
M24 Molinia caerulea – Cirsium dissectum fen meadow
Number of Key-Constant (+ Rare) Species in Harvested Seed
Summary of Results
NVC Absent
Under Representative
Representative
Over Representative
MG5
3 (1) 3 (-) 2 (1) 5 (-)
M23 1 (1) 4 (-) 5 (1) 1 (-)
M24 3 (5) 2 (-) 4 (1) 3 (-)
Need for – Seed-burden surveys Multiple-harvests Adequate donor sites More than one method of collection Good storage and control of pests
Lessons Learnt
Year prior to harvest and harvest year: Determine species composition & field scale
spatial variation, access, and Species flower/seed architecture & seed
ripening/shedding period(s), methods of collection
Determine areal contribution to seed yield (area / grasses & forbs) and number of harvests required (single or multiple)
Change land use to maximise seed yield (remove grazing pressure)
1 – Seed Burden Surveys
Need for multiple harvests because: Different seed yields between years (1992 &
1993) Species ripen at different times within
years:
2 - Multiple Harvests
Site (1992)
NVC June Early July
Late July
Aug Sept
Bryntirion MG5 2 18 13 9 6Glyn-yr-Henllan
M23 2 23 15 6 6Blaenclairch
M24 1 23 9 6 10
Preplanning - Access for harvest method Species composition Control of land use & management
Adequate yield of seed (area) –
3 - Donor Sites
Sowing Rate kg/ha
Grass @10
Forbs @ 5 Rushes & Sedges @ 3
Donor Size ha
8 1.3 2.3
More than one seed collection method available
More than one because of: Weather - dry standing crop Access limitations (steep, patterned & soft
ground) Selective harvest of seed / seed heads
(flower architecture, key species, weevil infestation)
4 - More Than One Method
Seed collected is valuable in terms of effort and limited resource
Reduced viability through infestation by mildews and white-shouldered house moth
If not sown on collection there is need for:
Drying & dry storage Insecticide treatment
5 - Storage & Control of Pests
Study is highly relevant to today’s drive to establish native plant grassland communities
Study provides basis for planning collection and evidence for achievability to planning authorities
Showed need for careful & informed planning, realistic & achievable programme spanning seed ripening times & a number of years, and sufficient donor resource
Conclusions
AcknowledgementsBritish Coal (former national coal company) for their foresight and funding of this study