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4 pp. / Originally published: 2002 / This is a list of sources for seed and plants for the Upland Southwest. Various sources for bulbs,wildflowers, grasses and reclamation seeds, vegetable seeds, fruits and nuts, trees and plants are listed.

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Vegetation dominated by heather and bracken, two common species of the UK uplands, is often nutrient limited and heavily influenced by climate. Thus, changes in climate or nutrient availability might be expected to have pronounced effects on growth and competition between these species. Mature heather and bracken turfs, transplanted from the field into 1 x 1 by 0.5 m deep plots, were subjected to factorial experimental treatments of root competition, shoot competition, summer drought, increased nitrogen supply and increased temperature for four consecutive years. The effects of root competition on the growth of heather and bracken were as great as those caused by the environmental treatments alone. Shoot competition had little effect on the growth of the two species, and thus, competition was concluded to occur predominately for below ground resources. Heather, in the building phase, was a superior competitor to bracken due to its extremely fine and invasive root system. Heather was able to compete with and deplete water from the roots of established bracken plants. Measurement of integrated of water use efficiency () and water use by droughted heather and bracken showed that the predicted environmental change scenarios are likely to cause an increase in the intensity of competition for water. There was no evidence of competition for nitrogen, despite nitrogen clearly limiting the growth of both species. The effects of the treatments on shoot phenology, morphology, photosynthetic physiology, biomass and below ground biomass have been examined. Above ground, heather was more responsive to the treatments imposed than bracken, having greater increases in shoot growth in favourable conditions, but greater decreases in shoot growth, and greater physiological acclimation, in stressed conditions, particularly drought in combination with increased nitrogen supply. Below ground, growth of bracken was extremely responsive whilst that of heather was not. However, even when bracken below ground growth was most stimulated, by increased nitrogen supply, it was still held in check by heather.

The concept of the ecotone was formalised by Clements (1 905) as a boundary zone between plant communities. Little research exists on the ecological importance or the geographical variability of these zones. Two types of boundaries are acknowledged: the ecotone and the ecocline. The ecotone is a sharp boundary; the ecocline a gradual boundary. The term 'transitional area' is proposed here to more accurately describe these areas as this research demonstrates that a complex continuum exists between the two end points. Additionally, mosaics often complicate the nature of the transition and may form a boundary type in their own right. Upland plant communities represent important semi-natural habitats within the British Isles. Effective management depends on an understanding of their structure and function. This research is primarily concerned with the description of structure (spatial pattern and variability in floristic composition) but explanation of these patterns is only possible through an understanding of function (vegetation dynamics). Pilot studies determined an appropriate methodology for studying transitional areas. The approach progressed from a linear transect to a two-dimensional rectangular transect. The pilot studies also evaluated a range of methods for data analysis. Extended field sampling followed which included 23 sites in 4 locations: Dartmoor, Snowdonia, North York Moors and Barra, Western Isles of Scotland. Data analysis exposed the complexities of the transitional areas sampled but 'noise' often obscured the true characteristics. To overcome this a Species Ratio Index Model was devised to identify the strength of signal for each boundary. The final characterisation of transitional areas is based on three main components: ecotone, ecocline and mosaics, each displaying varying amplitude. Of the sites sampled, few boundaries revealed single characteristics and the majority were far more complex than their observed patterns implied. On the basis of this characterisation a classification is proposed which incorporates both natural and anthropogenic factors. The classification represents an important contribution to the understanding of boundary types. This study reinforces the significance of boundaries in the landscape. The potential for future research is great, particularly through the development of a predictive model for management purposes.

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