Method notes, Exp I, “Genes and Environment”
Jason Fridley and Phil Grime, Fall-Winter 2004 + Fall
2005 update
See also details in Excel spreadsheet.
Soils
All soils were removed from the field, nearby the Buxton Climate Change
Laboratory in Harpur Hill, Derbyshire, chosen to
match the rendzina soil type at Cressbrookdale.
Two different batches of rendzina soil removed at
different times from the same location were used. The more calcicolous vegetation above the rendzina
soil was chosen about halfway down the slope of a limestone dale at
Buxton. Rendzina was removed (turf vegetation
down to bedrock, 20-30 cm deep), placed in plastic bags on site, hauled up with
a wench system (acknowledgement: Andrew Askew!), and transported back to Tapton. The soil was then dried a bit in greenhouses,
mixed in a cement mixer and mixed further by hand to remove major rocks, root
tussocks and large rhizomes, but was otherwise unamended
(and was noticeably rich in earthworms). Soil for the bottom third of
each pot was filled with a separately-removed rendzina,
from the same location as the fresh rendzina but
removed and stored as living turves at Tapton for __ years (8?). Turves
were allowed to dry out before soil was removed from roots with a pick, mixed
in a wheelbarrow and placed down the PVC pipes by hand. Soils were filled
in mid-December 2004, to within 3-4 cm of the top of each pot.
Crevices for the drought treatment (64 pots) were filled with washed 10
mm silica-based gravel from B&Q Warehouse (
Crevices for drought treatment
All 64 pots for the drought treatment were fixed to meter-long 40 mm
diameter PVC pipe filled with 50:50 mixtures of vermiculite and perlite. Pipes were capped at the bottom with a fine
mesh to encourage rapid drainage and fixed to the center
of secondary pot bottoms via a “tank connector”. 40 mm holes were cut out
the bottom of soil-filled pots and these pots were then placed inside the
pipe-connected pots, with rendzina immediately
touching the gravel. Root tubes were
attached to drought treatment pots (64 pots) on 2 June 2005. Terylene cloth from
the top of each root tube was removed 20 June 2005 to facilitate root
penetration into perlite/vermiculite mixture. Some roots had already penetrated up to 2 cm
below cloth. No shrinkage or expansion
of root tube mix was observed.
Pot layout
Fully randomized within four blocks.
Treatment Compositions and Planting design
Sixteen total species compositions were used: 7 monocultures (3 for each
genotype of Km and Cc, and the one genotype of Cr) and 9 mixtures.
Mixtures were each possible 2-species combination of the 3 Km and Cc genotypes,
plus one individual of the single Cr genotype. Mixtures thus included 5
planted individuals: one individual of Cr in the very center
of each pot, surrounded by two individuals of Km and two individuals of Cc
(same species on opposite sides along each radial diagonal), with Km and Cc
individuals spaced at the midpoint of the pot radius.
Km genotypes: 3, 4, 13 chosen from their performance in 16-genotype
boxes in B&G (2002 data)
Cc genotypes: 4, 9, 13 chosen from their performance in 1-genotype
boxes in B&G (2002 data)
Cr genotype: 13 chosen mostly due to large amount in stock; note
NOT in ExpII
Individuals were planted in the first week of January 2005, one species
and one genotype at a time, in the order Cr, Km, Cc. Pots were
subsequently watered frequently to promote transplant establishment and kept in
a warmed greenhouse over the winter of 2005.
Pots were placed in the outdoor garden at Tapton
on 22 March 2005, and fully enclosed by a protective cage by 22 May 2005.
Fertilizer added to HiTall treatments on 2 June 2005 (128 pots). 1.56g fertilizer added to each pot [180 kg/ha = 2nd highest treatment in Burke plots]. On 4-5 October 2005 64 of these pots (HiTall+Path treatment) were fitted with clear plastic collars wrapped around pots. Size of each collar 80 cm (wrapped circumference) by 42 cm (height). Collars were fitted on pots with staples.
Grazed treatments (LowCut; 212 pots) clipped at 2.5 cm height on 13 July and 4
Oct 2005; clippings not saved. 13 July
clipping coincided with Mark Bilton’s third census
and Chris Bennet and Elizabeth Richell’s
recording of reproductive and vegetative vigor of Fo in Exp II.
One Km4 individual was replaced
in pot 30 (block 1) on 27 May 2005.
Herbivory treatment:
On 3 October 2005 snails (Cepaea nemoralis)
and slugs (Deroceras reticulatum) were collected from Cressbrookdale
(near 10 x 10 m site, most uphill from there) and Buxton (bottom of dale) for
preliminary experiment on herbivory pressure. Four arenas (flats with clear plastic tops)
with four pots each were created, a cross of two species (Cc and Km) and two
herbivores (snail and slug). Each pot
included one individual of each genotype (3 genotypes for Km pots, 3 genotypes
for Cc pots). Plants will be monitored
for the next several weeks.