Gwybodaeth Modiwlau

To explore the nature of the plant community and examine the processes that operate between and within plant communities.

The module elaborates modern themes in plant community ecology. The first group of lectures concerns the nature of the plant community and how plant communities are inter-related at the landscape scale. Within the landscape it is possible to determine a basic matrix within which patches of other community types are encountered. Alternatively, complex mosaics may occur. Both reflect the pattern of resources and constraints that occur within a particular landscape in both time and space. In effect, landscapes can behave like "supersystems". Connectivity is important in the functioning of integrated landscapes, while populations of individual species may not be isolated, but rather, form metapopulations which contribute to their long-term stability.
The second section is concerned with changes in communities over time. They are not static, but change, often in apparently predictable ways. They may be directed by the sequence of species present (autogenic), or driven by environmental conditions that change over time (allogenic). The resource-ratio hypothesis has been suggested as the mechanism for "climax" vegetation, but multiple end points of change are evident within many areas.
Both human and natural phenomena may affect plant communities. Grazing animals may show a high incidence of specialisation in shaping the composition of plant committees while fire naturally causes biomass removal in many landscapes. Human use may represent simple biomass removal, as in hay regimes, alternatively, it may be selective removing particular species or particular groups of individuals (such as a size class) for a particular use, thereby affecting the community.
Finally, the description of plant communities and their distribution in space is discussed based on both numerical (ordination and classification) and descriptive phytosociological (represented by NVC) approaches.

The students will be expected to undertake a five-day field course to establish expertise in plant species identification in a range of contrasting Welsh habitats (e.g. sand dunes, hedgerow, mesotrophic grassland, and deciduous woodland). They will also be expected to complete detailed scientific illustrations of various species collected during the course, highlighting specific taxonomic characteristics used for identification. Information from identification at each location will be developed into surveys and interpreted according to the National Vegetation Classification System. During the final two days students will be divided into groups for completion of a small taxonomy / plant ecology project.