The Dynamic Landscape

Moist meadows

These are found in many parts of the world, in the lowlands in the oceanic climates in western Europe through to high altitudes in more continental climates (Table 6.2). Generally, these plant communities are more dominated by various cool season grasses from the genera, Agrostis, Alopecurous, Cynosurous, Festuca and Poa, than are drier meadows, and the forbs are typically capable of tolerating this competition. These communities are typically associated with soils of moderate fertility, and consequently species grow faster and form larger, more widespreading or taller individual plants than species of drier habitats. As a result, they are generally better able to compete with invasive weedy vegetation on fertile urban soils. As a result they are more likely to persist under these conditions than are species of drier meadows. These plant communities are generally most attractive between late spring and midsummer. Moist meadows are generally heavily dependent on cutting or grazing for persistence.

Wet meadows

These may occur either locally along drainage lines or more extensively where rainfall is very high and/or drainage is impeded. Even the most moisture

demanding of these species, for example, Primula will generally grow acceptably well without irrigation on retentive soils in parts of Britain that experience greater than 1,000 mm rainfall per annum. They will survive with less in northern regions with particularly cool summers. Other species, for example, Iris sibirica and Cirsium rivulare, will tolerate drier conditions. Given the absence of moisture stress, many of the species associated with these habitats are relatively tall, competitive species. Some spread aggressively by underground stems forming monocultural ‘clonal patches’, for example Filipendula ulmaria and Euphorbia griffithii, and once established will compete effectively with many invading species. Most of these species typically grow among cool season grasses, although, on fertile sites, the shade cast by tall forb species may result in low densities of these. Some wet meadows are subject to cutting and grazing cycles, whilst others are a more seminatural vegetation associated with sites that are too wet to support trees. Species from these habitats are typically less tolerant of the defoliation associated with cutting as hay.

Grasses are an important part of wet meadow vegetation. Where these grasses are either tussock forming, as in Deschampsia cespitosa or Molinia caerulea, or are tall clone-forming species, such as Calamagrostis epigejos, these species have a sufficent structural and textural quality to be used as grass only communities. On sufficiently moist soils, these communities provide an attractive transition between mown grass and woody vegetation types, and also provide strong design lines to contrast with architectural structures. Hitchmough (in press) has investigated the establishment of tussock grasses by field sowing.

More specialised wet habitats, in which tall vigorous plants may be restricted by infertility, low soil oxygen or grazing pressure, are often associated with small growing stress-tolerating forbs. Under these conditions, grasses are typically replaced by sedges (Carex) and rushes (Juncus). Many of the forbs in these habitats form discrete rosettes of

foliage, for example, asiatic Primula spp., Succisa pratensis, Lychnis flos-cuculi and Geum. Whilst often shade-tolerant, many of these species are not compatible with taller, more wide-spreading species. These species often reproduce by seed in plantings, whereas the tall clonal forbs of highly productive sites do not. Management to control larger invading species is required if these stresstolerating species are to be successfully employed in designed vegetation. Almost all of the species in Table 6.3 are highly unattractive to slugs and snails as adult plants, and flower between spring and midsummer.