This thesis set out to investigate the processes that determine the richness and composition of plant communities on derelict land in the West Midlands. Experimental work included vegetation surveys, soil seed bank investigation, field mapping and seed rain trapping methods. Interpretation of the data involved a range of approaches including vegetation classification and ordination, comparative analysis of plant functional attributes and the development of regression models incorporating landscape and habitat variables. Derelict habitats were identified as holding a diverse array of communities at the early stages of succession which are poorly represented by current vegetation classifications, functional diversity is however much lower in pioneer communities. The majority of these species employing the expected strategies of early succession notably high reproductive capacity and seeds which are small, highly dispersive and form persistent seed banks. Dense seed banks were typically formed on sites and were dominated by a small set of consistently occurring species. Changes in seed bank density and composition were consistent with time represented both by the chronosequence of sites and increasing soil depth. Little evidence was found to suggest that diversity or species composition is linked to site connectivity related to either patch density or the presence of linear features. These findings have considerable implications for application of principles of metapopulation and island biogeography principles to urban conservation. In particular the trend for planners to designate urban wildlife corridors is questioned as being probably of no benefit to native diversity and indeed these features are identified as being instead potentially significant pathways for invasive alien species. The most important factors influencing the composition of sites were seen to be those linked closely with past and present human activity. Particularly significant are the nature of dereliction substrates and haphazard disturbances such as fire and tipping which influence vegetation succession temporally and spatially.

The high floristic biodiversity value of ancient woodland is widely acknowledged, as is its status as a fragmented habitat of limited spatial extent. The distinctive vegetation of ancient woodland is an important factor in its conservation. Specifically, Ancient Woodland Indicator (AWI) species have been shown to be poor dispersers and incompatible with a fragmented habitat that is subject to environmental change. In recognition of their ecological importance, both Ancient Semi-Natural Woodland (ASNW) and Ancient Replanted Woodland (ARW) are protected by legislation. This thesis took the novel approach of examining the distinctiveness and community ecology of vegetation communities in all three woodland types of ASNW, ARW, and recent woodland. Importantly, analyses were based on new high-granularity primary vegetation and soil data. To address questions raised in the literature regarding the accuracy of ancient woodland and AWI identification, this research examined the metrics used to distinguish these habitats and species. Increasingly, the literature calls for further understanding of the ecological drivers of ancient woodland vegetation distinctiveness. In response, this research tested for differences in species composition of canopy, shrub, herb layer, AWI, and moss communities across all three woodland types. For AWI species, biotic, abiotic, and biogeographical variables were analysed for their contribution to community distinctiveness. Results highlighted the importance of consistency in metric selection when assessing the distinctiveness of ancient woodland and determining indicator species. In addition to the usual alpha scale measure of distinctiveness, assessing richness and community composition at the beta and gamma scales is recommended to inform conservation. Life traits and dispersal mechanisms were important differentiators for herb layer community composition among the woodland types. AWI richness was equally strongly explained by biogeographical variables as by ASNW, ARW, and recent status. Overall, this thesis supported ecological and biogeographical explanations for the distinctiveness of ancient woodland vegetation.

This thesis aims to understand the mechanisms involved in pollen transport and deposition in cave environments and the influence of different factors on the composition of the pollen assemblage, with special reference to the problem of the Neanderthal ‘Flower burial’ at Shanidar Cave, Kurdish Iraq. Limited systematic taphonomic work has been done in cave environments, with most of the studies on an ad hoc basis. However, the number of interconnected factors acting on pollen transport, deposition and accumulation in this kind of environments implies that models used for open-air sites are inadequate and demonstrates the need for further taphonomic studies. Surface samples from six caves located in the Zagros Mountains of Kurdish Iraq were collected along front-back transects and outside for comparison in order to evaluate the distribution of anemophilous and entomophilous taxa in relation to the sample location. Additional surface samples were collected from Shanidar Cave along a side to side and perimeter transects to better evaluate the pollen distribution. Water, airfall and animal dung samples were also collected to investigate the influence of those factors in pollen transport. Finally, stratigraphic samples collected during the excavation at the site were analysed for pollen and for particle size distribution. Results show that simple sac-like caves with little or no influence of factors such as water, humans and animals are characterised by broadly predictable patterns of pollen distribution with a positive correlation between anemophilous pollen and vicinity to the cave entrance and entomophilous pollen and distance from the cave entrance. Caves with active biotic vectors and/or more complex geomorphology show instead more irregular patterns. Cave SLS203 presents an inverse anemophilous/entomophilous distribution that is likely to be related to its geomorphological complexity (a second entrance at the back of the cave influencing the air circulation) and to the presence of animals. Shanidar Cave presents a very irregular distribution which is likely to reflect a combination of factors such as the mixing of surface sediments caused by the tourists visiting the site, the pollen transported by animals and that moved by the wind. Other factors, such as water input and cave entrance flora, seem not to play an important role in ii Kurdish Iraq, while they appear to strongly influence pollen distribution in caves elsewhere (e.g. Coles, 1988; Simpson, 2006). The stratigraphic samples were sterile or contained few pollen grains, probably because the aeolian nature of the sediments, deposited during stadials, with low pollen deposition and high sediment influx. Finally, clumps of pollen of both anemophilous and entomophilous taxa have been found for different taxa in all the caves. Leroi-Gourhan (1975) had suggested that similar clumps found in the vicinity of Shanidar IV remains were evidence for burial with flowers but their presence on the surface demonstrates that they can occur naturally and that other explanations should be considered. Moreover, the high amount of Lactuceae and the presence of older pollen grains in her samples suggest a strong taphonomic imprint not necessarily resulting from anthropogenic activity.

No description available.