Glamorganshire

Glamorganshire The vice-county of Glamorganshire can be roughly split into three areas. Gower has acidic sandy soils with clay between heathland commons. South of the M4, the Vale of Glamorgan is generally low-lying with clay, impermeable brown earths and sandy free-draining soils all of which are slightly calcareous and good for growing crops. North of the M4 the land grades into mountains and the soils are wetter stagnogleys much more suited to pastoral farming. Small scale arable cultivation was a feature of the mixed farming in the area as shown by the 1930s land use survey which is considered a low point in arable cultivation. Growing crops will probably have increased during the World Wars in the 20th Century as there was a greater need to be more self-reliant, and the advent of herbicides and inorganic fertilisers in the mid 20th Century has led to an increase in crop production in some areas as weed control has improved. Arable land has been restricted to the better cereal growing soils of Gower and the south of the Vale of Glamorgan in both the 1930s and 1990s land use surveys. However, there has been a 20% contraction in arable land between these two time periods and a concentration of arable land into larger blocks in the latter land use survey. This could be caused by a number of reasons including the general change in farming businesses towards more livestock farming and pastoral land; the increase in herbicides and fertiliser costs which may lie beyond the means of small-scale farms; and the volatility of cereal prices may also have led to a decline in small-scale arable cropping with high yields only breaking even in some years, thus larger farms becoming more economical and the coagulation of cultivated land. Glamorganshire is the richest vice-county with records of 24 out of 30 threatened plants. Some of the records of the threatened arable plants are considerably old such as large-flowered hemp-nettle Galeopsis speciosa and grass-poly Lythrum hyssopifolia. There are native populations of corn chamomile Anthemis arvensis, stinking chamomile Anthemis cotula, cornflower Centaurea cyanus and corn marigold Glebionis segetum which is often introduced in sown seed mixtures. Glamorganshire is the only place with recently recorded populations of corn chamomile, broad-fruited cornsalad Valerianella rimosa and corn buttercup Ranunculus arvensis and is the hotspot for shepherd’s- needle Scandix pecten-veneris in Wales. The latter two species prefer clay and impermeable soils and are also autumn germinating. The only two know populations of red hemp-nettle Galeopsis angustifolia are also present from shingle beaches in Glamorganshire and do not grow on arable land. Several species are only present on sand dunes and sandy fields including henbane Hyoscyamus niger, smooth cat’s-ear Hypochaeris glabra, prickly poppy Papaver argemone and rough poppy Papaver hybridum. One population of annual knawel Scleranthus annuus is present in grassland on Gower and is not on arable land. On one Gower farm there are very high populations of small- flowered catchfly Silene gallica, narrow-fruited cornsalad Valerianella dentata and broad-fruited cornsalad, as well as corn marigold, corn spurrey Spergula arvensis and field woundwort Stachys arvensis. This farm should be targeted for additional protection due to the coincidence of so many threatened arable plants. The distribution of corn mint Mentha arvensis is an oddity as it has generally been recorded at too small a scale to provide an accurate fix on location. This means that it appears to be relatively sparsely distributed across Glamorganshire whereas it may actually be more widespread. However, the small scale of the records, generally hectads (10x10km squares), may hide a population decline and further investigation of the population dynamics of this species is required across Wales. Two arable plants corn spurrey and field woundwort are widespread across the arable ground of Glamorganshire and Wales is probably the hotspot for these plants across the UK which can be sparsely distributed elsewhere. Twenty tetrads (2x2km squares) have three or more threatened arable plants and should be targeted for suitable management practices. Areas of Glamorganshire that qualify for Important Arable Plant Area status are present on Gower and the south central Vale. They have good assemblages of arable plants and should be targeted for arable plant conservation to maintain the diversity of these flowering species across the vice-county. There are nine tetrads considered to be of National Importance and 11 considered to be of County Importance for arable plants. Some farms in Glamorganshire with known populations of threatened arable plants have been regularly surveyed for arable plants. Two other more general surveys of farms under agri-environment schemes also took place between 2000 and 2010 providing a wider coverage of surveys. However, there has been no systematic survey of arable land in Glamorganshire and there have been new populations of threatened arable plants found, such as cornflower, on Gower. A rigorous survey targeting cultivated land on Gower and south of the M4 in the Vale of Glamorgan should be undertaken to provide more rigorous data and refine the targeting of arable plant conservation measures. Glamorganshire 1933-1949 Arable Land Use The extent of arable land in the 1933-49 period across Glamorganshire was restricted to the lower lying land covering 10759 ha. In total, 523 tetrads out of 632 tetrads had arable land use present. The 1930s are considered a low point in arable land use and the coverage of cultivated land may historically have been much greater. Locations with little arable land include the uplands and valleys in the foothills of the Brecon Beacons. Concentrations of arable land are present on the Gower peninsula, south of the M4 between Porthcawl and Cardiff and the M4 corridor west of Neath. Contains Ordnance Survey © Cyfoeth Naturiol Cymru, data © Crown copyright 2014. © Natural Resources and database right 2014. Wales, 2014. ± 5 km Glamorganshire 1979-1991 Arable Land Use Between the 1933-49 land use survey and 1979-1991 Phase 1 habitat survey of Wales there was a 20% contraction in arable land use across Glamorganshire. 8554 ha of arable land was identified in the Phase 1 habitat survey with cultivated parcels of land falling in 333 out of 632 tetrads. Although there hasn't been as dramatic a reduction in area of arable land compared with elsewhere in Wales, there has been a contraction in the range of arable land. Cultivated land is more focussed on the Gower peninsula, particularly between Rhossilli and Port Eynon and south of the M4 corridor in the Vale of Glamorgan where it has expanded slightly in coverage. This is offset elsewhere within the vice-county where it has contracted. Contains Ordnance Survey © Cyfoeth Naturiol Cymru, data © Crown copyright 2014. © Natural Resources and database right 2014. Wales, 2014. ± 5 km Glamorganshire Soil Map The most common soils in Glamorganshire fall within the clay category and is the dominate substrate for 437 tetrads. A general guide is that clays south of the M4 are formed over liassic rock and are neutral to slightly calcareous. The majority of arable land is associated with this area and parts of Gower on the sandy soils. The clays north of the M4 and Gower are stagnogleys formed over glacial deposits and are neutral damp-wet substrate. They are rarely calcareous and arable land is not particularly associated with these soils in this vice-county. Sandy soils are the dominant soil type for 115 tetrads, particularly along the coast, along waterways where river flows have deposited sandy material and to the West of Cardiff within the Vale of Glamorgan. The other soils category is the dominant substrate for 78 tetrads. This includes deep humus-rich soils that are present on commons and in upland areas and disturbed and man-made soils from mining activity. There are few large expanses of calcareous-based soils in Glamorganshire that could be categorised as 'limestone' but lime dominated soils are the scattered around the coast where the rock is exposed. The extent of calcareous influence is relatively small and for this reason only two tetrads for Flat Holm are considered to be calcareous soils. Contains Ordnance Survey © Cyfoeth Naturiol data © Crown copyright Cymru, 2014. © Natural and database right 2014. Resources Wales, 2014. ± 5 km Corn Chamomile Anthemis arvensis All of the historical pre-1986 and 1987- 2000 records of corn chamomile in Glamorganshire are thought to be natural populations arising from the soil seed bank rather than recent introductions from sown seed mixtures. The majority of these records are historical including the records around Cardiff, Barry, Aberdare and Port Talbot. There is one record from the mid-level category from the Worm’s- head on Gower. Three populations are within the recent post-2000 date category. Two populations are close together on Gower at Pitton and Middleton, but are thought to originate from sown seed. There is only one population of corn chamomile thought to be naturally occurring from the soil seed bank near Bonvilston. It has been regularly surveyed with numbers of individuals plants usually below 10 each year. This is thought to be the only extant population naturally occurring from the soil seed bank in Wales. Contains Ordnance Survey Vice-county Rare Plant data © Crown copyright and Register provided by the database right 2014. BSBI VC41 Glamorganshire Recorder December 2013. Contains data from the Tir ± Gofal Monitoring 2009-2012. Data maintained by the 5 © Welsh Government 2014. Vice-County Recorder and km provided by the Botanical Contains Plantlife Important Society of the British Isles Arable Plant Area database and Ireland and accessed data 2014. from the BSBI Distribution Database 2013.

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