Dissertations / Theses on the topic 'Sand dune ecology'

The importance of understanding the ecological functioning of coastal dune systems is emphasized as being fundamental to the correct management of the dune landscape. Dune vegetation along the Eastern Cape coastline, from Cape St Francis in the west to Kei Mouth in the east was described in terms of the distribution and phytochorological affinities of the taxa. At a regional scale species distribution was strongly influenced by both the climate, particularly rainfall, and the phytochorological affinities of the taxa. Seven communities were defined using TWINSPAN, and the interrelationships between these communities in anyone area appeared to be linked to a successional gradient. Dune Slacks are thought to play a key role in this successional sequence, and a temporal study of this community led to a conceptual model of plant succession in these dunefields. Climate, particularly rainfall and wind, are major factors influencing plant succession. Wind-borne sand causes the slacks to migrate in an easterly direction under the influence of the predominantly westerly winds, although easterly winds, mainly in summer months may reverse these trends. Autogenic changes appeared to be important in this succession, and a comparative study of a good example of a primary succession at Mtunzini in Natal was undertaken to elucidate the main mechanism of change. Eight communities that were identified here were concluded to be distnbuted along a gradient of increasing age, with successional changes predictable, linear and directional. Species were grouped in distinct zones along the continuum and edaphic changes (decrease in soil pH, increase in organic matter and exchangeable bases) were related to the community based changes in species composition. The mechanism of change supported the facilitation model of plant succession which is a modification of the original Clementsian concept. Similar results were found in the Eastern Cape, but due to the harsh environment, multiple pathways of succession exist. Data from this study lent support to the model of plant succession developed earlier, and confinned that the dune slacks played an important role in this facilitation by acting as centres of diversity. The foredunes were found to have an indirect role in protecting these slacks from salt spray and sand movement. The central theme of the management studies was to investigate the ecological consequences of recreational pressure within the dune environment. Current levels of beach utilization at East London were lower than other beaches in South Africa, but a general trend of increasing utilization due to sociopolitical changes can be expected. The suitability of questionnaire surveys to assess aspects such as the adequacy of facilities, perceptual carrying capacity and the beach users opinion of natural vegetation and preference for particular beaches was demonstrated. The dune vegetation was found to be sensitive to human trampling, but at current levels, the ecological carrying capacity will not be exceeded since results of the aerial census counts and questionnaire survey revealed that few people entered sensitive zones such as the coastal forest. More detailed long term studies on the susceptibility of dune vegetation to both trampling and off-road vehicle impacts revealed a low resilience of dune plant communities to these effects. Although susceptibility differed between the three communities tested, generally the greatest amount of damage occurred after the first few passages, and vehicles caused a more significant decrease in height when compared to trampling. Recovery rates were slow and low levels of repeated damage were sufficient to retard or prevent the recovery of the plants. Stricter control of vehicle use on beaches is therefore required, and in high use zones the ecological carrying capacity should be increased by providing access tracks if possible, or if not possible, by restricting access. A historical account of the process of dune stabilization showed that although first initiated in 1845, indigenous species were only used in the past three decades. The use of alien species has resulted in problems such as a reduction in the ecological integrity and aesthetic appeal of coastal systems. The techniques applied in the stabilization of drift sands with indigenous vegetation have been successful, as revealed by a quantitative survey of 17 sites in the Eastern Cape. Sites were grouped by multivariate analysis on the basis of their species composition, and variability between sites was dependent on the types of species planted. Selection of suitable species is therefore important and is discussed with respect to their natural distribution along the coast. The long term objective of stabilization should be the creation of functional, diverse, aesthetic ecosystems, since the intrinsic and economic value of the dune landscape for tourism lies therein. However, detailed studies should be undertaken prior to implementing a manipulative process such as dune stabilization, since ecological processes may be disrupted. An understanding of such processes is therefore important if one wishes to effectively manage the dune landscape.

Quantitative community descriptions, based on point quarter sample data, are made for a number of dune forest units along the East London coast. These are supported by multivariate classifications and ordinations which illustrate the inter community variation between the sampled seaward, landward and dune valley sites. Climax valley forest is floristically most characteristic and can be clearly distinguished from the seaward and landward thicket communities which tend to show a degree of similarity. Within-forest community differences are shown to be more significant than variation along the coast. This appears to indicate that climoedaphic gradients established laterally to the coast induce a greater floristic response than the rainfall gradient within the study area. The state of developnent within the dune soil profile and the rate and effect of salt spray deposition are considered to be important factors influencing dune forest succession and are discussed in some detail. An overview of certain other climatic variables as well as the geological features within the study area is also given. A phenology study of the dune forest, scrub-thicket and strand plant cornnunities shows some general patterns of flowering and fruiting phenorhythms. Although much variation was observed, there appears to be a bimodal hyperactive phenophase response which is thought to be related to rainfall or periods of favourable soil moisture conditions. A brief discussion of some of the positive and negative human influences on the coastline is given. This includes a description of the management activities carried out in the area as well as the demands placed on ·the coastal resource.

South African dune fields are severely threatened by human expansion and in the long run the stabilisation of many dunes will be necessary. The alien grass Ammophila arenaria is the most important drift sand stabiliser at present in South Africa. Although not invasive, the current impact of A. arenaria on the dune systems of South Africa is considerable, and thus the stabilising benefit of the grass seemed to may be outweighed by its negative consequences. It is therefore preferable to use indigenous sand stabilising species. In order to define guidelines for the application of indigenous plants for stabilisation, their autecology should be studied first to enhance the chance of successful stabilisation results. The main aim of the present thesis was to gather information on the life history processes of selected indigenous, sand stabilising foredune species. To investigate the growth of foredune pioneer species, the common pioneer Scaevola plumieri was followed over a three-year period to determine the growth season and leaf phenology. Soil-borne pathogens are known to influence the growth and vegetation dynamics of foredune species. To examine this effect on the South African foredunes the rhizosphere soil and the roots of several species were studied. To test the effect of the nematode fauna on succeeding plant species a transplantation experiment was carried out. The seed stage is the only life-cycle stage that can survive unfavourable conditions. Therefore, the seed ecology of several foredune species was studied extensively to determine the reproductive season, the seed production, the fate of seeds after shedding (germination, seawater dispersal), germination requirements and seed bank strategy. Seeds of the species Arctotheca populifolia, Ipomoea pes-caprae, Myrica cordifolia, and Scaevola plumieri were subjected to germination trials, field observations on seedling survival, and scarification and stratification experiments. This was done to obtain information about the germination requirements and to determine the reproductive season and growth season. The seed bank strategy of the foredune species, as well as the seed bank density, was determined by extensive sampling along the Cape coast. The species S. plumieri thrived under sand accretion situations, which makes it a good candidate for stabilisation purposes. The growth of S. plumieri was seasonal, with the highest leaf production during spring and summer. The stem position on the foredune had a strong effect on the overall performance of S. plumieri , with the stems situated on the landward face of the foredune showing higher leaf and seed production. Theiii nematode survey of soil and roots of several foredune species showed that all plant species featured a specific nematode fauna in the rhizosphere soil and the roots. The specific nematode fauna affected the growth of foreign plant species in the transplantation experiment, resulting in a lower root and/or shoot biomass production. Most of the foredune species produce seeds from spring to late summer. For S. plumieri the position of the stem on the dunes, as well as the predation of unripe seeds affected the number of seeds produced. The highest production was found for the landward faced stems. The S. plumieri seeds were able to float on seawater for at least three months without losing viability, as was observed for seeds of I. pes-caprae. The seeds of M. cordifolia, however, sank after a few days, but their viability was not affected. The rhizome fragments of A. arenaria and S. virginicus floated for 120 days, whereas the fragments of E. villosa sunk after one day. The viability of S. virginicus fragments was affected by the duration in seawater by an increase in sprouting time. The seeds of all species tested germinated readily under controlled conditions, except S. plumieri seeds which required a long lag-phase before germination. In the field the seeds of A. populifolia, I. pes-caprae and S. plumieri germinated, producing many seedlings. Only the seedlings of A. populifolia and S. plumieri survived. Of the species found in the foredunes 57% was represented in the soil seed bank. For most species, the seeds that were found in the seed bank showed viability of at least 40%. Many of the seeds found were older than one year, suggesting a short-term persistent seed bank. The present study is a start in filling the gap in information on dune pioneer and foredune species. The conclusion was that in general all species in the present study were easy to grow under controlled conditions, and thus could be used for stabilisation purposes. When the more rapidly growing pioneer species are planted in combination with succeeding foredune species, a functional and aesthetic ecosystem could be created.

In dryland environments, the availability of soil moisture is the primary control on plant species’ distributions. In the sandhill regions of the northern Great Plains, vegetation establishment has transformed highly mobile, desert-like dune fields into stabilized landscapes covered by mixed-grassland prairie. This study examines how dune stabilization has modified the spatiotemporal distribution of soil moisture resources. An ergodic (space-for-time) approach was used, comparing soil moisture dynamics on active and vegetation-stabilized dunes in the Bigstick Sand Hills of southwestern Saskatchewan. Results indicate that while dune stabilization has enhanced near-surface soil moisture availability, deeper profile soil moisture recharge is reduced. Through better understanding how vegetation has modified soil moisture dynamics in stabilizing sandhill regions, better management practices may be implemented to maintain water resource availability and ecosystem health.
xii, 97 leaves : ill., maps ; 29 cm

The research was undertaken at a sand dune system located along the South East coast of England, known as Sandwich Bay. Sandwich Bay has attracted a number of environmental designations, including Special Areas of Conservation and a Site of Special Scientific Interest due to the presence of rare habitats and flora found predominantly at this single site, such as Himantoglossum hircinum (lizard orchid) and Orobanche caryophyllacea (bedstraw broomrape). The research focus centred on concerns surrounding ecological change resulting in the loss of grey dunes, an Annex 1 priority feature. Sandwich Bay has been classed as a Special Site of Scientific Interest in unfavourable condition (Natural England, 2014), based primarily upon the loss of fixed grey dune habitats to neutral grasslands (SD8 to MG1/MG12 NVC classifications). The aim was to identify causative factors that might account for the observed historic and any current changes in vegetation. The research was conducted between October 2011 and September 2014, and focused upon hydro-chemical interactions in the environment. Analysis was undertaken by the installation of 103 dipwells across the 520 ha site, in order to obtain groundwater samples. The hydro-chemical and botanical analysis indicated that the vegetation composition was not affected significantly by the chemical constituents within the groundwater. However vegetation composition was significantly modified by variable surface elevation and the related height of the water table. An additional investigation focused upon the identification of management techniques that are thought to be beneficial to dune vegetation restoration. Three management trials were located at three different sites, investigating four different management treatments. Analysis showed that there was a significant difference between the various management treatments and species composition. Vegetation analysis indicated that both cut and remove, and burning, as management treatments encouraged a greater diversity of species, particularly in sheltered eutrophic areas.

Understanding the mechanisms and adaptations that allow only certain species to thrive in the potentially stressful foredune environment requires a knowledge of the basic ecophysiology of foredune species. Ecophysiological measurements were conducted on the foredune pioneer species Arctotheca populifolia (Berg.) Norl., Ipomoea pes-caprae(L.) R. Br. and Scaevola plumieri (L.) Vahl. and showed significant differences among species with respect to the physiology associated with biomass production, water and nutrient relations. Differences related to CO₂ assimilation included differences in photosynthetic and respiratory rates, susceptibility to light stress and leaf and stem non-structural carbohydrate concentrations. These resulted in differences in primary production rates of shoots. Mechanisms leading to the differences in CO₂ assimilation among species included differences in stomatal behaviour, carboxylation efficiencies, efficiencies of utilisation of incident photosynthetic photon flux density (PPFD) and rates of ribulose-1,6-bisphosphate (RuBP) regeneration. Correlated with differences in photosynthetic capacity were differences in chlorophyll contents but not differences in leaf nitrogen content. Differences in interspecific stomatal behaviour resulted in significantly different transpiration rates which in combination with differences in assimilation rates resulted in differences in water-use efficiency. The absolute amounts of water transpired, although significantly different among species, were moderate to high in comparison with species from other ecosystems and were typical of mesophytes. Transpiration rates in combination with plant hydraulic conductances and soil water availability resulted in leaf water potentials that were not very negative and none of the investigated species showed evidence of osmotic adjustment. The volume of water transpired by each of the species per unit land surface area was estimated from the relationship between abiotic factors and plant water loss. These relationships varied among species and had varying degrees of predictability as a result of differences in stomatal behaviour between the three species. The water requirements of A. populifolia and S. plumieri were adequately met by the water supplied by rainfall and the water stored in the dune sands. It was therefore not necessary to invoke the utilisation of ground water or the process of internal dew formation to supply sufficient water to meet the requirements. However, I. pes-caprae despite its lower transpiration rates and due to its higher biomass, lost greater volumes of water per unit dune surface area than either A. populifolia or S. plumieri. This resulted in periods of potential water limitation for I. pes-caprae. Incident light was the most important determinant of leaf photosynthetic CO₂ assimilation and transpiration, particularly as a linear relationship between incident PPFD and atmospheric vapour pressure deficit (VPD) could be demonstrated. Whole plant photosynthetic production by S. plumieri was shown to be light limited as a result of mutual shading despite high incident and reflected PPFD occurring in the foredune environment. The leaf hair-layer of A. populifolia was shown to be important in reducing transmitted UV and hence reducing photoinhibition but it also caused reduced transpiration rates because of the thicker boundary layer and thus increased leaf temperatures. The nutrient content of above-ground plant parts of the investigated species were typical of higher plants despite the low nutrient content measured for the dune soils. With the possible exception of nitrogen the nutrient demand created by above-ground production was adequately met by the supply of nutrients either from sand-water or from aquifer-water transpired by the plants. Differences in the volumes of water transpired, and hence the quantity of nutrients potentially taken up via the transpiration stream, resulted in interspecific differences in above-ground plant macronutrient content. The reallocation patterns of nutrients differed both between the various nutrients measured and interspecifically. Standing biomass and the density of plants per unit land area was low in comparison to that of other ecosystems and was different among investigated species. This may be important in maintaining the adequate supply of resources (water, nutrients and light). As a result of the interspecific differences in biomass when production was expressed per unit land surface area the resultant productivity was not dissimilar among species. Productivity was high when comparisons were made with species from other ecosystems. No single resource (water, nutrients or light) could be identified as the controlling factor in the foredune environment and a combination of both resource stress and environmental disturbance are likely to be involved. Physiology, production, growth and growth characteristics conveyed certain adaptive advantages to these species in respect to both resource stress and environmental disturbance. Interspecific differences in these adaptations can be used to offer explanations for the observed microhabitat preferences of the three investigated species. Furthermore features common to all three species offer some explanations as to why these species and not others are able to inhabit the foredunes.

Machair is a habitat found predominantly in coastal areas of the north–west of Scotland and is characterised by a low-input, rotational arable system interspersed with semi-natural grasslands. Land management is an essential part of the machair system as both intensification and abandonment threaten its future. Little is known about this system in terms of its below ground communities. A survey was conducted over a three season, two year period for molecular determination of bacterial, AM fungal and nematode community structure. Cropped, fallow and undisturbed grassland were sampled; soil and roots associated with two commonly occurring species and composite soil samples were collected. In addition the effect of edaphic factors and vegetation composition on soil communities was assessed, both in the field and in greenhouse experiments. Results show that although all of the examined factors impacted the community structure of the three soil groups to some degree, the strength of this effect varied between groups. Bacterial communities were mainly affected by temporal factors, particularly year, possibly due to variation in soil moisture content. AM fungal community structure also varied considerably with season, but the mechanisms behind this were less obvious, with both abiotic and plant factors playing a role. AM fungal community structure varied with different plant hosts but also with soil moisture content. In contrast to both bacteria and AM fungi, nematode communities showed a strong response to land use although temporal factors and differences between locations were also observed. Grasslands harboured a distinctly different community structure from cropped and fallow, largely as a result of variation in bacterivores and carnivores. Vegetation composition and soil moisture content were also found to affect nematode community structure. This study has revealed that machair soil communities seem to be highly complex, dynamic and adapted to the changeable conditions that persist.

Arbuscular mycorrhizas (AM) are mutually beneficial symbiotic associations between the roots of plants and certain Zygomycetous fungi. The role of AM fungi in coastal sand dunes has been explored in many parts of the world, though little work has been conducted in South African dune systems. This study aimed to investigate the presence and extent of mycorrhizal colonisation of a coastal sand dune in South Africa. The roots of five plant species (Scaevola plumieri, Arctotheca populifolia, Ipomoea pes-caprae, Ehrharta villosa and Chrysanthemoides monilifera) were sampled along a foredune profile at Old Woman's River in the Eastern Cape. These roots were assessed for the percentage mycorrhizal colonisation they supported. Spores extracted from the rhizosphere sand of each plant species were counted and identified to genus level. Results were related to seasonality and the position of the plants along the profile. All plant species were found to be mycorrhizal. Percentage colonisation ranged from 0-92%, depending on plant species and season. Mycorrhizal colonisation was generally highest in the winter months, and especially so in I pes-caprae and E. villosa. The extent of various mycorrhizal structures in root tissue varied between plant species. Spore numbers ranged from 0-48 spores 100g-1 sand with highest numbers occurring in winter. S. plumieri and A. populifolia were associated with greatest spore abundance. Four fungal genera (Glomus, Acaulospora, Scutellospora and Gigaspora) were identified. Distribution of these genera showed seasonal variations between plant species. A bioassay, using Sorghum, was conducted to test the inoculum potentials of sand from the Scaevola hummock and the IpomoealEhrharta dune. Highest percentage colonisation occurred in plants grown in the Scaevola sand, which also had the lowest root and shoot measurements. The bioassay confirmed that AM propagules are present and viable, even in the mobile sand of the foredune. This study showed that mycorrhizal colonisation and spore numbers varied seasonally, but that the extent of this was dependent on plant species. The position of plants along the foredune profile tended to be less important than plant species. It is thought that the growth cycle and rooting system of each plant species determines seasonal cycles and abundance of AM fungi. Variation within fungal populations probably also impacts on this. Knowledge of the presence and distribution of AM fungi in this system paves the way for more detailed studies which need to examine the role of these endophytes in South African sand dunes.

This thesis investigates whether topography has a quantifiable effect on the spatial distribution of landcover within an inland sand dune ecosystem. To accomplish this, an investigation was undertaken to compare the associations between various topographic characteristics and landcover distribution within the Great Sand Hills (GSH), Saskatchewan. The methodology comprised a spatial analysis of digital topographic and landcover data. In terms of landcover diversity, results shows that there is a moderate association between topography and landcover diversity in the GSH, and that results vary with spatial scale. Similarly, results show modest predictability for one particular community type (trees) thought to be strongly related to topographic position in this region. Several environmental factors are proposed that might overprint the topography-landcover association. Overall, this thesis expands the geographic context of the link between topography and landcover, while also demonstrating the utility of high resolution topographic and landcover data and the importance of spatial scale.
x, 90 leaves : col. ill. ; 29 cm

Ammophila arenaria (L.) Link is a European sand binding plant which was introduced to South Africa in the 1870's for the purpose of dune stabilisation. Because of its known invasiveness along the west coast of North America, and the problems South African ecosystems experience with alien invader plants, it was deemed necessary to study the biology and ecology of this species in South Africa. The aim of this thesis is to establish the potential invasiveness of A. arenaria on Cape coastal dunes and assess whether its use for dune stabilisation is still justifiable. A. arenaria occurs nowadays between the Langebaan area on the west coast and Gonubie in the Eastern Cape. Although widespread, the grass appears to occur only in areas where it has been planted. Its unaided spread may be prevented by adverse climatic conditions. Studies on the community biology of South African A. arenaria communities as compared to indigenous dune plant communities and natural A. arenaria communities in Europe cannot confirm the aggressive behaviour that A. arenaria shows in California and Oregon. In South Africa, A. arenaria does not exert strong floristic control over other species or outcompete and replace them, neither does it alter the topography of South African beaches and dunes. It forms weaker species associations and tends to develop communities of little species variability along the coast, thereby proving its alienness in South Africa, but this does not imply its invasiveness. Studies on succession of A. arenaria stabilisation areas show that monospecific A. arenaria plantings can be succeeded by a species-rich indigenous dune scrub or dune fynbos within a few decades. Plant-parasitic nematodes have been recorded, which may play an important role in the succession of A. arenaria stands in South Africa as was observed in Europe. Monitoring of A. arenaria communities and indigenous communities over nearly three years shows that A. arenaria is not spreading and replacing indigenous plants but in fact rather being replaced by the latter. A. arenaria profits from a superior sand burial tolerance but is affected by adverse climatic factors, mostly the lack of rainfall and strong radiation. In comparison to the indigenous dune grasses Thinopyrum distichum and Ehrharta villosa, it does not show any superior demographic traits such as an unusually high growth rate or large aboveground biomass production. Although A. arenaria produces viable seed in South Africa, the indigenous grasses show better germination and seedling establishment in the field. This study indicates that A. arenaria is not invasive in South Africa, nor likely to become an invader species in the near future. However, more research is required to confirm these results and more caution recommended regarding the further use of this alien grass for dune stabilisation.

The purpose of this study was to test the hypothesis that food availability was responsible for the low population density, larger home range size, high degree of daytime activity and longer activity periods of wood mice living in a sand dune habitat compared to those living in deciduous woodlands in Grampian, North-East Scotland. An experiment was set-up whereby one population of mice was provided with superabundant food in the form of wheat and the parameters mentioned above were measured and compared with an adjacent control population with natural levels of food. Seasonal changes in population density, demography and breeding biology were obtained via live-trapping. The home range size and activity patterns were measured by the use of radio-telemetry. The presence in. or absence from the nest was recorded automatically by a minichart recorder. The supplemented population had a higher density (2-3 times), higher recruitment rate (2-8 times), earlier start to the breeding season, increased juvenile recruitment and lowered weight of sexual maturity compared to the control population. Supplemental food did not prevent the normal population decline over winter, improve survival rates or extend the breeding season into winter. It was concluded that food interacts with behavioural and other environmental factors to. limit population density. The supplemented mice had significantly smaller home range sizes both in the breeding and non-breeding seasons compared to the control mice. The supplemented mice moved significantly shorter distances per night compared to the control mice. The supplemented mice were strictly nocturnal, emerging from the nests after sunset and returning before sunrise, and spent significantly less time active, both in the breeding and non-breeding seasons compared to the control mice. No regular short-term rhythms were observed in the individuals monitored in both populations. Diet analysis showed that the mice were feeding mainly on arthropods throughout the year. The low density and mobility of the food resources would account for the differences in home range size and activity patterns of the control mice mentioned previously.

A study of the dynamics and functions of a coastal dunefield at the Bushman’s River Mouth in Kenton-on-Sea was conducted to provide essential information for the formulation of a management strategy based on an ecosystem approach. Bi-monthly tacheometric surveys were undertaken at the Westbourne Road Car Park dunefield to investigate the sedimentological processes. Changes in the topography, the amount and rate of sand accretion were monitored. Accretion and progradation were the dominant long-term sedimentological processes at the site. Long-term spatial variation in these processes corresponded to the temporal pattern of sedimentation in the river mouth while short-term variation resulted from dynamics inherent to the types of dunes present. Factors affecting aeolian accretion at the site are topography, river mouth configuration, dune types and the presence of vegetation as well as the seasonal wind regime. A vegetation study, recording species present, cover and abundance of the plants along the surveyed transects, was also conducted to examine the progressive establishment of vegetation. Five plant communities were discerned namely, saltmarsh, pioneer, enriched pioneer, open scrub, closed scrub and scrub-thicket communities. The spatial distribution of these communities coincided with the north-westerly development of the sandbank. A successional trend in community change occurred along a gradient of increasing diversity, complexity and age. Initially, autogenic changes wrought by pioneer species facilitated the recruitment and survival of other species and commenced succession at the study site. Multiple successional pathways were discussed in relation to subsequent species establishment that occurred after facilitation. The amalgamation of ecological data with a social study in the form of public perception surveys allowed for a greater understanding of the present interactions between the ecosystem and the demands placed on it. The area primarily functions as a recreational site that offered numerous beach and water-related activities. A lack of information regarding the ecology and management programmes influenced public perception of the environment and management issues in general. Different management perspectives and the use of the information presented in this study were also discussed.

Ecological evaluation techniques have been used to classify or evaluate the relative conservation worthiness of a portion of the Eastern Cape coastal zone from Cannon Rocks to Port Alfred. A system-based approach, using a basic GIS, was used to compare three aspects of the coastal zone. Two existing planning documents (EMATEK/s Coastal Vegetation Importance Rating plan and CPA's Cape Coastal Conservation plan) were statistically compared - based primarily on the size and number of the landscape fragments (environmental criteria polygons). The resultant plan, an Intermediate Sensitivity Class map, was further integrated with the biophysical aspect of the coastal zone - coastal dunes. The final map is the product of these overlays to be used as a-working overlay for coastal zone decision-making. This is an Environmental Sensitivity map, which has no particular direct reference to any particular biophysical criteria, which categorizes the coastal zone according to the environmental sensitivity or conservation worthiness of the site. The categories are listed according to a sliding-scale of sensitivity or worthiness. There is, however, it strong association between the final map and the vegetation status of the coastline, as a direct result of the vegetation rating map and indirectly from the perception based coastal conservation plan. The formation of most assessment or evaluation plans are based on the vegetation status of the area. This map can be overlayed over the particular stretch of the coastline which it covers and the particular conservation status noted. There are numerous techniques available for assessment and evaluation each having their own specific merits and advantages. This plan, however, is a first attempt at integrating other specific plans into a single working document for the coastal zone manager.

Arbuscular mycorrhizal (AM) fungi are root and soil inhabiting symbionts with higher plants. The fungi are especially nutrient-function efficient in nutrient deficient soils. There have been innumerable studies of AM fungal facilitation of plant nutrient uptake in controlled environments. Comparatively little similar investigation has been undertaken in natural soils, including investigation of taxon specific nutrient-function efficiency in the phylum. Plant diversity and frequency, soil chemistry statuses, and AM spore diversity and abundance were sampled in an interrupted-belt transect in an aggrading dune sytem on west-coast India, followed by foredunes and transect nutrient amendment experiments in selected plant species. The transect extends 175 m inland from mean high-water mark (MH-WM). Examination showed nutrients were consistently deficient. A plant zonation pattern and increasing frequency over the transect were indicated, as well as decreasing pH and increasing organic matter (OM)-amendment AM species diversity gradients. Plant zonation does not correlate with soil chemistry. There was a distinct soil transition at the 175 m point and evidence of further system partition between foredune and behind-foredune regions. Plant and AM demographies bore no resemblance suggesting neither is driven by the other. Four AM genera were recovered, Acaulospora, Gigaspora and Scutellospora in high abundance, Glomus in comparatively low abundance. The two co-dominant species, A. spinosa and Gi. margarita, displayed divergent strategies in OM amendment. Certain AM taxa may be functionally associated with particular soil nutrients. There was no evidence of taxon-specific nutrient-function efficiency.

Rehabilitation is a dynamic process influenced by factors related to more than one field of ecology. It is therefore necessary to consider all these components when assessing the rehabilitation, although in the initial stages the successful revegetation of the disturbed areas is the most important criterion. Richards Bay Minerals, on whose mining site this project was carried out, is dredge mining heavy minerals on the north coast of Natal, where they have rehabilitated mined areas since 1978. This project has been carried out to establish: 1) The success of their dune forest rehabilitation using quantitative techniques. 2) The available seed bank in their rehabilitation stands. 3) The similarities in the succession taking place in rehabilitation stands compared to the revegetated stands in the vicinity of Richards Bay. 4) The best methods for creating alternative vegetation communities, especially grasslands, with a high species diversity on the mined tailings. This study reviews only the success of rehabilitation of the natural vegetation but other studies focusing on the insect, reptile, mammal and bird populations are also being undertaken by other researchers. No particular method of determining the success of vegetation rehabilitation has been chosen by restoration ecologists. Therefore in this study a broad range of quantitative techniques were used to show whether successional changes are occurring in the vegetation and physical environment. The results obtained from sampling the rehabilitated vegetation have shown that both the species richness and diversity are increasing as the returned vegetation matures. Levels of soil properties such as Sodium, Phosphate, Calcium and percentage organic matter have also risen with increasing stand age. Community complexity is also increasing with stand age, and TWINSPAN and DECORANA plots have separated out the differently aged stands based on their differences. A "pilot" study was done on the seed bank present in the rehabilitation stands. This has shown the presence of large amounts of early successional, mostly herbaceous species. Seeds of later successional and woody species were scarce which may be a result of the sampling intensity used. However seeds of late successional ground cover species were found in the older stands. Comparisons between the natural revegetation of disturbed areas in the vicinity of Richards Bay and the rehabilitation stands revealed similarities in both species composition and complexity. Species richness and diversity values are comparatively similar for the younger revegetated and older rehabilitation stands, and lWlNSPAN and DECORANA analysis techniques clustered the samples recorded from these areas in close proximity on their relative plots. The oldest revegetated sites contain a number of species found in the rehabilitated vegetation but as Acacia karroo has thinned-out in these stands many of these other species are now mature individuals. Attempts at rehabilitating an area of grassland at Richards Bay Minerals has not produced satisfactory species diversity and experimental manipulations were used to try and increase the diversity of the existing Eragrostis curvula dominated community. Of the several treatments used for the manipulation, a combination of burning and further topsoiling was the most successful in reducing Eragrostis importance and in increasing the species richness. Grassland topsoil spread directly onto the bare tailings produced an extensive vegetation covering over a short period but species richness was not significantly greater than for the existing Eragrostis dominated grassland, and further treatments and management needs to continue if this technique is to be employed. Only a limited amount of alien infestation of the rehabilitated areas was evident from the sampling undertaken during this research. As the removal of alien plants is an ongoing process and the rehabilitation stands are continuously monitored to identify any new invaders, this is not expected to become a problem. From the results of work done overseas and the rehabilitation carried out in South Africa it appears that it is possible to return natural vegetation communities on mined areas. That this is a lengthy process is to be expected but by manipulating the vegetation and continuously monitoring the process it may be possible to speed up development. Areas in need of further research have been identified based on the findings of this project. This will help to reinforce the undertaking of management proposals that will enhance the vegetation recovery and the success of the rehabilitation programme.

When considering the large amount of work done on dune ecology, and that a number of the classical ecological theories originate from work on dunes, it is apparent that there remains a need for physiological and mechanistic explanations of dune plant phenomena. This thesis demonstrated that in the extreme coastal environment dune plants must survive both high rates of burial (disturbance), and low nutrient availability (stress). The ability of four species to respond to these two factors corresponded with their position in a vegetation gradient on the dunes. A low stem tissue density was shown to enhance the potential stem elongation rate of buried plants, but reduced the maximum height to which a plant could grow. Such a tradeoff implies that tall light-competitive plants are able to survive only in stable areas, while burial responsive mobile-dune plants are limited to areas of low vegetation height. This stem tissue density tradeoff was suggested as the mechanism determining the zonation that species show within the dune vegetation gradient present at various sites in South Africa. Finally, detailed investigations of dune plant ecophysiology found that: 1) The resources used in the response to burial derive from external sources of carbon and nitrogen, as well as simple physiological and physical mechanisms of resource allocation. 2) The leaves of dune plants were found to be operating at one extreme of the photosynthetic continuum; viz efficient use of leaf nitrogen at the expense of water loss. 3) Contrary to other ecosystems, the environmental characteristics of dunes may allow plants to occupy a high disturbance, high stress niche, through the maintenance of lowered competition. 4) At least two mobile-dune species form steep dunes, and are able to optimise growth, on steeper dunes, such that they have to grow less in response to burial than plants that form more shallow dunes. In this thesis, it was shown that the link between the carbon and nitrogen economies of dune plants was pivotal in determining species distributions and survival under extreme environmental conditions. As vast areas of the world’s surface are covered by sand dunes these observations are not just of passing interest.

An investigation of ecosystem functioning of sandy beaches in the Nelson Mandela Bay Municipality (NMBM) was carried out with the aim of describing their type and pollution status. Water salinity, temperature, pH, beach slope, water inorganic nutrient concentrations, urea, and chlorophyll-a concentration as well as the composition of zooplankton, phytoplankton, meiofauna, benthic microalgae and bacteria were examined at thirteen beaches. The beaches were classified into three types: short beaches; long beaches with surf diatoms; and long beaches that import biomass (without surf diatoms). Of the thirteen beaches, five were non-polluted and eight polluted with polluting human activities in and around them. Most beaches were dominated by fine sand except for St. Georges Strand where the particles were medium to fine sand and Maitland’s River Beach, Bluewater Bay and Sardinia Bay that had coarse sand. Nutrient concentrations ranged from 1.98 ± 0.10 μM to 19.30 ± 3.02 μM nitrate; 4.88 ± 1.00 μM to 11.97 ± 1.00 μM ammonium; 0.67 ± 0.00 μM to 2.31 ±1.00 μM soluble reactive phosphorus; and 0.00 to 0.03 ± 0.00 μg l-1 urea-N. Chlorophyll-a concentrations ranged from 0.04 ± 0.02 to 1.57 ± 0.11 μg l-1. Chlorophyll-a concentrations were negatively correlated to ammonium for all beach types (short beaches: r = 0.94; long importing beaches: r = 0.95 and surf diatom beaches: 0.94) and to nitrate for short and long importing beaches (short: r = 0.97 and long importing: r = 0.85). By contrast, a positive correlation was found between observed between chlorophyll-a concentrations and urea for surf diatom beaches (r = 0.93) and for long importing beaches (r = 0.73). Chlorophyll-a concentrations were negatively correlated to short beaches (r = 0.99) and long importing beaches (r = 0.76). The E. coli and total coliforms in all the sampled beaches were within the recommended South African water quality guidelines for contact recreation as specified by DWAF (1995) except at New Brighton Beach (2 419 total coliforms/100 ml and 1 853 E. coli cells/100 ml) and St. Georges Strand (274 total coliforms/100 ml). Diatoms dominated the phytoplankton and benthic microflora; calanoid copepods dominated the zooplankton and deposit-feeding nematodes dominated the meiofauna in all the beaches with no changes found at polluted beaches.

Studies of the dunefield systems crossing the Cape St. Francis headland in the Eastern Cape have focused on the role that wind plays in sediment transfer in coastal dunefield systems, with limited consideration of the role of water. The aim of this study was to improve understanding of the morphology, processes and patterns within the Oyster Bay HBD system, focussing particularly on surface water and groundwater interactions and the role of surface water in sediment transfer across the dunefield system. An extensive field survey was conducted, to collect related data, complimented by spatial and temporal analysis of the study area using GIS. The key findings from this research were the apparent differences between the western and eastern regions of the dunefield with regard to specific drivers and the respective processes and responses. Wind is the major driver of change up to and across the crest of the dunefield. In the eastern region water (ground water, surface water and the Sand River System) is the primary agent of sediment flux through processes of aggregation and slumping as well as episodic events including debris flows. This study has highlighted a need for further quantitative studies that investigate the movement of sediment through dunefield systems such as this (where water is at or near the land surface). The paradigm that sediment flux is entirely due to wind is almost certainly simplistic, and deeper understanding of these systems is needed
Maiden name: Elkington, Lauren

Orientador: Carlos Frederico Duarte da Rocha
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-09T17:01:38Z (GMT). No. of bitstreams: 1 Miranda_JivanildoPinheiro_D.pdf: 7646850 bytes, checksum: 1b29966bda6798dfbb87bba528797710 (MD5) Previous issue date: 2007
Resumo: Neste estudo investiguei a riqueza, composição e distribuição local da herpetofauna do Parque Nacional dos Lençóis Maranhenses (PNLM), Maranhão, Brasil. Realizei 47 expedições, totalizando 235 dias de amostragem utilizando o método de procura visual limitada por tempo. Adicionalmente, estudei a ocorrência de atropelamentos de vertebrados na rota de acesso ao parque. Assim, registrei 63 espécies da herpetofauna no PNLM, sendo 21 espécies de anuros, 12 de lagartos, 24 de serpentes, duas de anfisbenas, três de quelônios e uma de jacaré. Destas espécies, 52 (E 82,5%) ocorrem apenas na restinga. As demais espécies ocorrem no campo de dunas do parque. Em relação aos atropelamentos, realizei cerca de 10896 quilômetros de amostragem. Encontrei 206 carcaças de vertebrados atropelados, distribuídas por 55 espécies. O grupo de vertebrado mais atropelado, em número de espécies (23 espécies) e de indivíduos (69 indivíduos), foi a classe Reptilia. Apesar do PNLM ser enfatizado do ponto de vista paisagístico, este estudo mostra que seus ambientes possuem significativa riqueza de espécies da herpetofauna. Estas espécies ocorrem principalmente no ambiente de restinga, o qual corresponde a apenas 21% da área do parque. Devido a crescente visitação turística e do aumento de empreendimentos na área, é importante que ações para a conservação da restinga do PNLM sejam urgentemente implementadas
Abstract: Herpetofauna richness, composition and local distribution (sand dunes or restinga habitats) were studied in Lençóis Maranhenses National Park (LMNP), Maranhão state, northeastern Brazil. I carried out 235 days of sampling using the method of visual search limited by time. In addition, I studied road killed vertebrates in the access route to the park (a road that crosses restinga habitats). Thus, I recorded 63 species of the herpetofauna (21 anurans, 12 lizards, 24 snakes, two amphisbaenians, three turtles and an alligator) in LMNP. Fifty-two species (E 82,5%) were found only in restinga habitats. Concerning to road killed animals, I carried out 10896 km of sampling and I found 206 carcasses of vertebrates, corresponding to 55 species. Reptilia was the vertebrate class with the largest number of species (23 species) and individuals (69 individuals) killed. Overall, the great number of species occurring in restinga habitats and high incidence of reptiles road killed in the route to the park, highlight the importance of actions to improve conservation in restinga habitats, which currently comprise only 21% of the total area protected by the park
Doutorado
Ecologia
Doutor em Ecologia

Foi realizado um trabalho de pisoteio experimental na vegetação de dunas do Parque Estadual da Serra do Mar, Núcleo Picinguaba, Ubatuba, SP. Dez parcelas permanentes foram instaladas, cinco no verão e cinco no inverno, subdivididas em 6 tratamentos, que receberam pisoteio controlado nas intensidades de 25, 75, 200, 500 e 1000 passadas, além do controle (sem pisoteio). O procedimento foi repetido em dois anos consecutivos. A cobertura e a altura relativa da comunidade e a cobertura das principais espécies da área foram avaliadas periodicamente ao longo de cada ano. As diferenças entre os tratamentos foram analisadas através do Teste de Friedman. A comunidade apresentou redução na cobertura e na altura da vegetação, mas sua recuperação ocorreu rapidamente. Os efeitos do pisoteio variaram com a estação do ano e com o número de ciclo do impacto, sendo mais evidentes no inverno e no segundo ano independente da estação. A altura decaiu mais rapidamente que a cobertura e demorou mais tempo para se recuperar. Não houve diferenças significativas entre o controle e os tratamentos de menor intensidade (25 e 75 passadas) nem entre os de média e grande intensidade (200, 500 e 1000 passadas), indicando que o uso da capacidade de carga recreativa não é um bom parâmetro para a área estudada. Analisando os dados obtidos pode-se afirmar que a comunidade estudada apresenta alta resistência e resiliência aos efeitos do pisoteio. O número de espécies aumentou com os anos do experimento, mas a maioria delas tem características de plantas invasoras. Três meses após o impacto as espécies apresentavam cobertura semelhante à observada antes do pisoteio. Os dados indicam que as espécies apresentam diferentes padrões de resistência e de resiliência. A Poaceae Panicum racemosum foi a espécie mais resistente ao impacto, e foi classificada como indiferente ao pisoteio; Hidrocotyle bonariensis foi a mais sensível, mas se recuperou rápido e superou os valores iniciais, sendo identificada como favorecida pelo pisoteio. Blutaparon portulacoides apresentou resistência e resiliência intermediárias, mas foi, aos poucos, eliminada da área pelas outras espécies, sendo classificada como desfavorecida pelo pisoteio. Considerando os resultados obtidos, uma forma eficiente de manejo da área é a concentração do uso, direcionando a visitação nas áreas de ocorrência da espécie mais resistente, evitando o lado esquerdo da praia cuja vegetação permanece mais estruturada. Recomenda-se o monitoramento periódico da área para evitar alterações drásticas na estrutura e na composição da vegetação.
Experimental trampling was conducted in a coastal sand-dune community located at "Serra do Mar State Park" in Southeastern, Brazil. It was used 10 permanent plots, five trampled in summer and other five in winter. The trampling intensities were 25, 75, 200, 500 and 1000 passes besides a control area (without trampling) in each plot. The procedures were repeated in two years. Response to trampling was assessed by determining species composition, vegetation cover and height evaluation in six evaluations during each year. The differences between trampling intensities were accessed with Friedman Test. Although there was loss of vegetation cover and height the study area was recovered in a few months. There were on trampling effects between season and years of impact. Effects were more noticeable for winter plots and for the second year of trampling. Reductions in height occurred with less impact and it took longer to recover. Neither 200, 500 and 1000 pass interference showed statistical differences between them, nor the control and 25 or 75 pass interference did. This suggests that the Recreation Carrying Capacity is not a good parameter to control visitors' impact in the area. The data analyses showed that the community has good resistance and resilience. The species number increased during the study, but most of the plant species were intruders. After three months, species cover was round the same as before trampling. The species showed different patterns of resistance and resilience, Panicum racemosum was the most resistant species. It was classified as neutral to trampling impacts. Hidrocotyle bonariensis, classified as favored, was the most sensible one, but it was recovered very fast, reaching higher cover values. Blutaparon portulacoides was classified as injured because although it had an intermediate behavior on resistance, it was almost eliminated from the plots as other species showed up, A management option that comes form this work is to concentrate public use on areas where the most resistant specie occur, avoiding the beach left side where vegetation is more preserved. It is important to monitor vegetation periodically to avoid drastic changes on vegetation structure or composition.

This practicum is a reference for vertical gardeners in cold climates. Winnipeg, Manitoba is explored, however findings may be applied to other cities in similar climates. First, the history of vertical gardening is discussed, then the types of vertical gardens currently on the market are described. These can be classified into two categories: soil bearing or non-soil bearing. Most designs are modular pre-planted systems that can be attached to any wall, as long as it satisfies the structural requirements recommended by the manufacturer. The benefits of vertical gardening have been shown to be rather extensive, covering a wide range of areas. Aesthetic improvement, reduction of the Urban Heat Island (UHI) effect, improvement of air quality, stormwater absorption, noise reduction, native habitat integration, reduction of heating and cooling costs for buildings, food production, marketing, and biophilia are all benefits explored in detail. Difficulties associated with vertical gardening are discussed, specifically the lack of knowledge and awareness of vertical gardens, lack of empirical evidence (or missing details in existing research), overall cost and lack of financial incentives, lack of industry codes, and various associated risks. Design framework exists within microclimate conditions unique to vertical gardens, as well as neighbourhood and regional (micro)climates. Theories relating to the study of green walls covered include the human ecosystem model, urban reconciliation ecology, habitat templating, the urban cliff hypothesis, and wall ecology. Suitable habitat templates identified for vertical gardens in Winnipeg are cliffs, sand dunes, alvars, mixed grass prairie and prairie potholes. Design parameters to be followed for vertical garden design in Winnipeg are to ensure that lightweight materials are used, to provide insulation to protect plants from sudden temperature changes, to choose plants that grow in the region and are adapted to grow in areas with limited soil, increased wind, varying degrees of sunlight (depending on orientation), and increased pollution and salt spray depending on location.
October 2015

Monospecific stands of Acacia karroo establish naturally on disturbed coastal dunes in KwaZulu-Natal, South Africa. While the A. karroo successional pathway is successful in rehabilitating mined dunes at the Richards Bay Minerals mining company (RBM), the same pathway has become arrested in the coastal dune forest at Cape Vidal in the Greater St. Lucia Wetland Park. This study examines the efficacy of the A. karroo successional pathway for restoring disturbed coastal dune forests. Dispersal of seeds and successful recruitment of seedlings are essential for habitat restoration. Seed and seedling banks were compared between previously disturbed A. karroo stands and adjacent forest at Cape Vidal. Different seed bank composition and higher seed bank richness in the forest suggest that seed dispersal into A. karroo stands is limited. Protected seed banks in A. karroo stands had increased seedling richness, indicating that dispersal limitation does not fully explain the lack of seedling establishment. At RBM, the seed bank richness of A. karroo stands increased with age since mining. While cumulative species richness of the seed bank of the oldest A. karroo stand at RBM was marginally lower than that at Cape Vidal, successful rehabilitation at RBM is associated with low seedling mortality. Consequently, forest tree species richness is high at RBM in the A. karroo stands and is converging on natural forest richness and composition. Although seed dispersal is reduced, it does not totally limit establishment of forest tree species in A. karroo stands at Cape Vidal, which implicates a post-establishment factor. Soil fertility potentially reduces seed germination and seedling growth. Soil nutrients in A. karroo stands at Cape Vidal were similar to those in the adjacent forest, and total nitrogen levels in A. karroo stands at Cape Vidal were higher than at RBM. Thus, soil conditions were unlikely to be limiting tree regeneration in A. karroo stands. Total nitrogen accumulated in the oldest stand at RBM at a rate of 10.0 g.m2.y(1 and a similarly rapid rate occurred at Cape Vidal. Therefore the A. karroo stands were not nitrogen limited. Nitrogen supplementation experiments at Cape Vidal demonstrated that a range of forest tree species establish in A. karroo stands regardless of nitrogen level, but there is low survival of seedlings. Thus, nitrogen availability is not arresting succession at Cape Vidal. Herbivory can also inhibit seedling recruitment. Selective feeding may enhance the persistence of species with defences against herbivory, such as A. karroo, ultimately altering the tree community composition. Browsing and trampling by large mammalian herbivores in A. karroo stands at Cape Vidal decreased survival and growth of forest tree seedlings. Large herbivores such as kudu, waterbuck, bushbuck and red duiker preferentially used the A. karroo stands as they offer abundant food and their topography allowed easy movement. This topdown pressure reduced recruitment, growth, and survival of seedlings of undefended species. Few wild herbivores occur at RBM, which allowed succession to proceed unhindered, ultimately restoring coastal dune forest at this site. Despite successful rehabilitation of coastal dune forest on mined dunes at RBM, limited seed dispersal and high levels of herb ivory have arrested succession at Cape Vidal. Thus, the A. karroo successional pathway must be implemented only after careful consideration of site-specific factors such as distance to a source of propagules and the intensity of herbivory in the system. In areas where herbivore densities are high, management interventions focusing on reducing herb ivory and encouraging visitation by seed dispersers are necessary for the successful use of this successional pathway.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

Biological invasions provide a unique opportunity to study the mechanisms that regulate community composition and ecosystem function. Invasive species that are also ecosystem engineers can substantially alter physical features in an environment, and this can lead to cascading effects on the biological community. Aquatic-terrestrial interface ecosystems are excellent systems to study the interactions among invasive ecosystem engineers, physical features, and biological communities, because interactions among vegetation, sediment, and fluids within biophysical feedbacks create and modify distinct physical features. Further, these systems provide important ecosystem services including coastal protection afforded by their natural features. In this dissertation, I investigate the interactions and feedbacks among sand-binding beach grass species (a native, Elymus mollis (Trin.), and two non-natives, Ammophila arenaria (L.) Link and A. breviligulata Fernald), sediment supply, and dune shape along the U.S. Pacific Northwest coast. Dunes dominated by A. arenaria tend to be taller and narrower compared to the shorter, wider dunes dominated by A. breviligulata. These patterns suggest an ecological control on dune shape, and thus, coastal vulnerability to overtopping waves. I investigate the causes and consequences of these patterns with experiments, field observations, and modeling. Specifically, I investigate the relative roles of vegetation and sediment supply in shaping coastal dunes over inter-annual and multi-decadal time scales (Chapter 2), characterize a biophysical feedback between beach grass species growth habit and sediment supply (Chapter 3), uncover the mechanisms leading to beach grass coexistence and whether A. breviligulata can invade and dominate new sections of coastline (Chapter 4), and examine the non-target effects resulting from management actions that remove Ammophila for the recovery of the threatened Western Snowy plover (Charadrius alexandrinus nivosus) (Chapter 5). I found that vegetation and sediment supply play important roles in dune shape changes across inter-annual and multi-decadal time scales (Chapter 2). I determined that a biophysical feedback between the beach grass growth habits and sediment supply results in species-specific differences in sand capture ability, and thus, is a likely explanation for differences in dune shape (Chapter 3). I found that all three beach grass species can coexist across different sediment deposition rates, and that this coexistence is largely mediated by positive direct and indirect species interactions. I further determined that A. breviligulata is capable of invading and dominating the beach grass community in regions where it is currently absent (Chapter 4). Combined, these findings indicate that A. breviligulata is an inferior dune building species as compared to A. arenaria, and suggest that in combination with sediment supply gradients, these species differences ultimately lead to differences in dune shape. Potential further invasions of A. breviligulata into southern regions of the Pacific Northwest may diminish the coastal protection ability of dunes currently dominated by A. arenaria, but this effect could be moderated by the predicted near co-dominance of A. arenaria in these lower sediment supply conditions. Finally, I found that the techniques used to remove Ammophila for plover recovery have unintended consequences for the native and endemic dune plant communities, and disrupt the natural disturbance regime of shifting sand. A whole-ecosystem restoration focus would be an improvement over the target-species approach, as it would promote the return of the natural disturbance regime, which in turn, would help recover the native biological community. The findings from this dissertation research provide a robust knowledge base that can guide further investigations of biological and physical changes to the coastal dunes, can help improve the management of dune ecosystem services and the restoration of native communities, and can help anticipate the impacts of future beach grass invasions and climate change induced changes to the coast.
Graduation date: 2012
Access restricted to the OSU Community at author's request from Sept. 22, 2011 - March 22, 2012

The impact of development on coastal ecological processes within the coastal zone is often noted as being of ecological concern, due to the suggested destabilization of dune systems as a result of construction activities and post construction impacts such as stormwater disposal, trampling and other artificial influences on, in particular, the plant ecology of the frontal dune systems. Given that the stability of frontal dune systems along the Kwa Zulu Natal north coast is often attributed to the maintenance of vegetation and seral progression on such systems, the identification of changes in dune plant communities that may arise from the influence of proximal or adjacent activities was sought to be identified. Utilising data collected from a number of sites in the Kwa Dukuza Municipal area, the classification and ordination of environmental and botanical species information collated over approximately 6 months was undertaken. The results of this investigation indicate that: Species composition differs in terms of richness and abundance in the three frontal dune vegetation zones sampled. 2 3 4 5 Some species occur in all three zones and others are confined to one zone only. Bearing and the associated influence of wind, the slope and length of the beach, and the steepness ofthe dune face all influence the species composition at any particular site The influence of anthropogenic activities on dune synusia is such that human influence on one species may disrupt associations between species and may result in attenuation or '" reversal of seral movement. Anthropogenic impacts influences species composition at different sites by causing some species to decline abundance or disappear from a site and others to invade or oust established species. In Zone I the species that appears to be most affected by human activity is Gazania rigens, which appears to dominate in sites of high human activity, at the expense of Sporobolus virginicus. In Zone IT under high human activity species such as Cynanchum obtusifolium, Rhoicissus digitata and Sporobolus virginicus dominate, while the woody species Mimusops caffra and Eugenia capensis, as well as the liane Gloriosa superba appear to decline or be ousted from this Zone. In Zone Ill, Asystasia gangetica, is a dominant species where low to moderate human impacts are encountered, while where human impacts are high, species common to Zone I, such as G rigens may become prevalent, ousting A gangetica and grasses such as S virginicus may be ousted by more competitive species such as Stenotaphrum secundatum. It is thus concluded that human activities in and around the frontal dune system may be influential in re-inforcing aeolian impacts on sites with bearings affected by strong prevailing winds.
Thesis (M.Sc.)-University of KwaZulu- Natal,Durban, 2004.

This study focuses on the ecological restoration of a coastal dune ecosystem on the east coast of Vancouver Island that supports bird migration. The area is also a part of the traditional homelands of the Tsawout First Nation. Because environmental degradation has impaired the functioning of both ecological and cultural systems, the restoration of this ecosystem requires a distinctive approach. An “ethnoecological” approach to restoration is presented that seeks collaboration between ecological science and traditional ecological knowledge in order to restore the ecological integrity and human connection to this culturally significant landscape. Guided by the values of the Tsawout community, and the practice of good ecological restoration, I make recommendations for short and long term restoration actions. A set of ethnoecological restoration guidelines are presented to help guide future projects with the dual mandate of ecology and culture. Finally, opportunities for making connections between this project and other regional initiatives are explored in an attempt to restore links in the migratory habitat chain.

Resprouting is an important means of plant regeneration especially under conditions that do not favour regeneration through seeding such as frequent disturbances, low productivity, unfavourable soil conditions, extreme cold and limited understorey light availability. Sprouts may be advantageous over seedlings because they have higher survival and growth rates than seedlings, since they use resources from parent plants unlike seedlings that have to acquire their own resources. Resprouting is well documented for ecosystems that experience severe disturbances that damage aboveground biomass. For example, resprouting is important for plant persistence against fire in fire-prone savannas and Mediterranean shrub-lands, and hurricanes and cyclones in tropical forests. In these ecosystems, resprouting often results in multi-stemming, because this dilutes the risk of damage among many stems, improving the chances of individual survival. This study was conducted at coastal dune forest at Cape Vidal in north-eastern South Africa, where there is a high incidence of multi-stemmed trees due to resprouting in response to chronic disturbances of low severity. This study examines (1) the importance of resprouting to tree survival and dynamics in an environment where disturbance severity is low but pervasive, and (2) how this resprouting strategy differs from the more familiar sprouting response to severe disturbances such as fire and hurricanes. Analysis of the relationship between multi-stemming and a number of disturbances potentially causing multi-stemming revealed that stem leaning and substrate erosion were the most important disturbances associated with multi-stemming. There were fewer multistemmed trees on dune slacks that had a stable substrate and were protected from sea winds than on dune crests and slopes that had unstable substrate and were exposed to sea winds. Trees resprouted and became multi-stemmed from an early stage to increase their chances of survival against leaning caused by strong sea winds and erosion, and occasional slumping of the unstable dune sand substrate. These low severity disturbances are persistent and are referred to as chronic disturbances in this thesis. As a result of these chronic disturbances, both single and multi-stemmed trees had short stature because taller individuals that emerged above the tree canopy would be exposed to wind damage. Under chronic disturbances plants may manifest a phylogenetically determined sprouting response. However, in this study resprouting and multi-stemming were the results of the tree-disturbance interaction and not a property of a plant or species and were not phylogenetically constrained. Because the disturbances are predominantly of low severity, leaning trees were able to regain the vertical orientation of the growing section by turning upward (a process referred to as ‘turning up’ in this study) and hence survive without resprouting. Species that were prone to turning upward had a low incidence and degree of leaning of their individuals, low frequency of loss of primary stems and high abundance of individuals. Although turning up is less costly to the individual than resprouting, it could only be used by leaning trees that had small angles of inclination and were not eroded. High intensities of the latter require that individuals resprout to survive. The form and function of resprouting varied between seedlings and juvenile and mature trees. Resprouting in seedlings resulted in a single replacement shoot, unlike sprouting in juvenile and mature trees that resulted in multi-stemmed trees. Like sprouting in juvenile and mature trees, sprouting in seedlings was not phylogenetically constrained. Resprouting in seedlings increased seedling persistence; hence species with more sprout seedlings had larger individual seedlings and seedling banks. Resprouting in seedlings increased the chances of seedling recruitment, whereas resprouting in juvenile and mature trees increased the chances of an established plant maintaining its position in the habitat. After disturbances of high severity, which destroy the photosynthesizing parts, plants resprout using carbohydrates stored below- or above ground. In this study, good resprouters stored more carbohydrates both below- and above ground than poor resprouters. The carbohydrates were mobilized for resprouting after disturbance. More carbohydrates were stored in stems than in roots because the prevailing disturbances were mostly of low severity and hence above ground resources were readily available. Similar to storage by plants in severely disturbed habitats, carbohydrates were stored by reserve formation, which competes for carbohydrates with growth and maintenance and forms permanent storage, rather than accumulation, which temporarily stores carbohydrates in excess of demands for growth and maintenance. Stored carbohydrates are not necessary for resprouting of plants after disturbances of low severity because they can resprout using resources remobilized directly from the disturbed photosynthesizing parts. However, in this study, stored carbohydrates served as a bet-hedge against occasional severe disturbances that occurred in addition to chronic disturbances. Allocation of carbohydrates to permanent storage diverts them from growth and reproduction and hence good resprouters had lower growth rates, seed output, seed size and seedling recruitment than poor resprouters. However, the costs of these traits that resulted in low recruitment from seed by good resprouters, were compensated for by high persistence of established individuals of good resprouters through recruitment of sprout stems. This study demonstrates that resprouting is not only advantageous in severely disturbed environments, but also in environments where disturbances are of low severity but nevertheless confer an advantage on individuals that persist. Thus in forest environments where aboveground biomass is seldom destroyed and individuals are relatively long-lived, resprouting can confer significant fitness and selective advantage on individuals.
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

This study examines foredune evolution along a 2100 m section of coast adjacent to the Tugela River. The foredunes vary in both height and shape along the study area and form the southern most extension of the Tugela foredune-ridge plain. Sand accumulation and erosion was measured at regular intervals over a 30 month period by tacheometric surveys. The foredunes and beaches are comprised of over 99 % sand. The sediment was predominantly composed of quartz and feldspar with subordinate lithic fragments. The quartz grains display conchoidal fractures and mechanical v-shaped pits and curved grooves. The beach and dune sand is well sorted and slightly negatively skewed with a mean grain size of 1.62 ф. The vegetation structure and floristic composition of the foredunes are explored. A range of factors influencing foredune morphology and evolution, including canopy density, height and distribution, wind velocity and a variety of ecological and environmental processes are examined. Ridge and swale morphology as well as alongshore variation in the dunefield could not be related to biological processes. The development of a foredune-ridge topography depends on a large sediment supply from the Tugela River over the long-term. Periods of high discharge introduce a fresh source of sediment to the littoral zone. Reworking of fluvial sediment landwards results in wide beaches. Onshore winds transport the sand from the beaches to the foredunes. Scaevola thunbergii encourages rapid vertical accretion and hummock dunes are formed. Lateral extensive invasion by seedlings may result in the hummock dunes joining to form coast parallel foredunes. Under periods of reduced sediment discharge erosion of the shoreline results in steep narrow beaches. Despite a negative beach budget foredunes continue to accrete vertically. Marine erosion results in either the complete destruction of embryo foredunes or their landward shift. Natural breaks in the dune crestline were attributed to changes in the delivery of sediment to the beaches. The processes operating in the study area conform to Psuty's (1988,1989) sediment budget model of foredune development. Sediment availability to the coastline produces characteristic morphologies.
Thesis (M.Sc.)-University of Natal, Durban, 1998.

The legislative management of Off-Road Vehicles (ORVs) on beaches has evolved over a period of time in response to a range of influences and changing circumstances within the various social, institutional, economic and biophysical systems. The impact of ORVs on beaches in South Africa is multifaceted and when viewed holistically incorporates the interaction between the biophysical, social, economic and institutional environments. This Study focuses only on the legislative and biophysical environments associated with the impact of ORVs on beaches. Sustainable coastal development draws attention to the "process" character of sustainable development that needs to be worked towards over time in an iterative manner. It highlights the need to take into account the current reality of prevailing circumstances, the uncertainty of the future, limited understanding of coastal ecosystems and communities, and the complex interactions between and within the human and non human components of the environment. An understanding of the ecological integrity and effective governance dimensions (being the focus of Study), although only two of the five dimensions of sustainable coastal development, contributes towards an understanding of the sustainability of the impact of ORVs on beaches within the South African context. The legislative environment is investigated from the management perspective of the national Department of Environmental Affairs and Tourism. This Study determines whether effective governance is being achieved through the ongoing management of the impact of ORVs on South African beaches. The institutional management at a national level has resulted in the conditional banning of ORVs from beaches, which has resulted in promoting the ecological integrity of beaches, therefore contributing towards sustainable coastal development. The physical system is investigated where appropriate in terms of the biophysical parameters within which ORVs are managed on beaches within the inter-tidal zone as per the ORV General Policy (1994). In order to understand the biophysical system within which ORVs are managed, the existing literature and research concerning the impact of ORVs on beaches is reviewed, including existing literature on beach geomorphology and beach biota. A Case Study Area was selected for an experimental investigation to determine the biophysical impact of ORVs on sandy beaches. The experiment was conducted at Leven Point, north of Cape Vidal situated on the KwaZulu-Natal north coast within the St Lucia Marine Reserve. The ORV General Policy (1994) has been superseded by the ORV Regulations (2001), which do not however, specify the biophysical delineation of the management of ORVs on beaches. This Study has included recommendations applicable to the management of ORVs on beaches in South Africa in terms of the ORV Regulations (2001). These recommendations advocate the conservation of the dynamic biophysical environment of the inter-tidal zone on beaches, and the need to take a sustainable coastal development approach to applications for Recreational Use Areas (RUAs) in terms of the ORV Regulations (dated 21 December 2001).
Thesis (M.Sc.)-University of Natal, Durban, 2003.

The present study arrived at investigating the influence of supplementary food on a developing rodent community on the coastal dune forests north of Richards Bay, South Africa. Four sites were selected for the field experiment. Each of these study sites comprised a treatment and control grid. Sunflower seeds were provided on the treatment grids and the response thereof on rodent population and community variables were measured. Each of the grids were trapped on a monthly bases as to follow the cumulative effects that supplementary food may have had on the rodent populations and the community. The amount of seed taken was measured. The minimum number of animals alive, as well as the survival and reproductive rates were calculated for the rodent community and each species on all the grids. Various community variables (richness, diversity and Bray-Curtis dissimilarities) were calculated. The diet of each species was investigated as to confirm that the species present take seeds as a food item. Five rodent species were recorded on the newly rehabilitating areas. They include Otomys angoniensis, Mastomys natalensis, Mus minutoides, Saccostomus campestris and Dendromus melanotis. Most of these species are granivores and consume seeds as part of their diet with the exception of 0. angoniensis that is a herbivore. Seeds form the main part of the diet of M natalensis, M minutoides and S. campestris and it could be assumed that sunflower seeds can form part of their diet. Bray-Curtis dissimilarity values indicated that treatment and control grids became more dissimilar as time progressed. Supplementary food had no significant effect on the species richness and rodent community densities. However, the supplementary food on treatment grids resulted in the significant decrease in species diversity in contrast with control grids. This decrease in species diversity was not as a result in the change in species richness, but was rather the result of the proportional increase in the number of individuals of M natalelensis on the treatment grids. Mastomys natalelensis were the most dominant species. Their numbers increased on the treatment grids where they continued to dominate the rodent community. Mus minutoides was the second most abundant on the study grids. This species, however, did not responded to the food supplied and decreased in numbers on both the treatment and control grids. No relationship could be demonstrated between any pair of species for treatment or control grids. Interspecific interactions between species could therefore not be illustrated. The possible existence of intraspecific interactions for M natalensis is a more plausible explanation as to why their numbers increase on treatment grids were food was no more limiting than on control grids. Species specific survival rate of M minutoides decreased with time for the treatment and control grids combined. This coincide with the decrease in the minimum number of M minutoides alive and may be explained by the successional changes in habitat characteristics. Factors other than the availability of sunflower seeds must therefore influence M. minutoides numbers on the newly rehabilitating areas. The survival probability of M natalensis individuals were not influenced by the supplementary food. Factors other than supposedly increased survival are responsible for their high numbers that were maintained on treatment grids. Supplementary food had no influence on the reproductive rates of adults and the proportion of juveniles present in each of the species present. This imply that the effects that supplementary food had on the rodent community and the species it contain, were not established through the reproductive effort and output. This suggests that immigration may be the reason for increased numbers of M natalensis individuals rather than their survival probability or reproductive performance. Sunflower seeds were provided as supplementary food to increase only a small part of the resource spectrum. Food supplementation for this developing rodent community resulted in a decrease in diversity as MacArthur's (1972) model predicted. However, the decrease in diversity 76 was not as a result of a decrease in species richness, but rather the result of the increase and maintained dominance of the pioneer species M natalensis. No interspecific interactions could be demonstrated, and it is speculated that intraspecific interactions play an important role in the M. natalensis population. The rodent community is therefore shaped by factors other than interspecific interactions, with supplementary food having no effect on species other than M natalensis.
Dissertation (MSc (Zoology))--University of Pretoria, 2006.
Zoology and Entomology
unrestricted

Tese de doutoramento em Biociências, na especialidade de Ecologia, apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra
The genus Corema has an amphi-atlantic distribution and includes two species: C. album, endemic to the Atlantic coast of the Iberian Peninsula and C. conradii, endemic to the Northeastern coast of North America. Both species are dioecious coastal shrubs; plant sexual dimorphism is noticeable in the floral structures and the presence of fruits in female plants. Due to the different costs of reproduction, male and female plants have different physiological requirements and performance. The main hypothesis driving this work is that sex-related differences in physiology and performance lead to demographic biases of the Corema populations and influence the interactions of male and female plants with their associated biota. Three C. album populations in the west coast of Portugal (both in sand dunes and in coastal woodlands) and three C. conradii populations in the east coast of Canada were studied. The demography of the C.album populations was characterized to identify sex related biases, and a competition/facilitation effect of C. album plants on the neighbouring flora was assessed. Adjustment of fruit maturation by female plants was investigated in the context of the serial adjustment hypothesis (Lloyd 1980). The interactions of male and female Corema plants with soil dwelling biota were investigated to assess sex-related and habitat related differences; these included nematode and fungal endophyte communities, particularly ericoid mycorrhiza (ErM), associated with the rhizosphere of both species. A possible interaction between the nematode communities and ErM colonization was investigated. Systematic male biases in sex ratios were not found in the studied C. album populations and most sampled plots showed complete spatial randomness in the distribution of the individuals of both sexes, suggesting that female plants can compensate for the higher reproductive effort they bear. Female C. album plants presented low fruit sets, but infructescences with more fruits also had larger and heavier drupes. Together with the dynamic environmental conditions and the lack of evidence of pollen limitation, this suggested the low fruit sets are the result of an adjustment of the fruit production and maturation to resource availability. Such a strategy can ensure the production of the optimal number of fruits in each season, as well as minimize the delayed costs of reproduction that accumulate along several reproductive periods, by adapting effort to the conditions of each reproductive event. As the dominant plant species in the surveyed areas, C. album canopy cover had a detrimental effect on all plant life-forms (Raunkiær 1937) except for geophytes. Sex-related differences were found in the composition and abundance of the plant parasitic nematode (PPN) communities for both Corema species. The plant phenological stage significantly influenced the abundance of free-living nematodes, PPN genera and nematode community indices in C. album. Significant sex-related differences in PPN community associated with C. album and on the abundance of three PPN genera (Criconema, Hemicriconemella and Meloidogyne) were apparent during the fruiting season but not during flowering, suggesting that interactions with the nematode community were dependent not only on plant sex but also on the phenological stage of the plant. The fungal endophyte community associated with the Corema roots included several taxa: ericoid mycorrhizal fungi, ecto mycorrhizal fungi, and dark septate endophytes. Sex-related differences were not detected in the composition, or in the diversity of the fungal endophyte community in either Corema species, nor in the percentage of colonization of the roots by ErM in C. album; plants growing in the same area had similar endophyte communities, irrespective of plant sex. The diversity of endophytes and root colonization frequency in C. album were higher during the fruiting season, but no statistical interaction between plant sex and phenological stage was detected on the root colonization frequency, indicating that ErM of C. album do not respond to changes in resource demand by the plant. Interactions between the ErM and the nematode community were only apparent during the fruiting season, when ErM colonization frequency was highest. Corema album and C. conradii are the dominant shrubs on the coastal barrens and sand dunes they inhabit. These ecosystems are of particular importance as they represent the transition between the sea shore and inland areas, protecting the productive activities inland from salt spray, winds and erosion. The present work provides the first insights to the below-ground ecology of these coastal species emphasizing the importance of an integrative perspective of the interactions among organisms for the understanding of coastal ecosystems.
O género Corema tem uma distribuição anfi-Atlântica e inclui duas espécies: C. album, endémica da costa Atlântica da Península Ibérica e C. conradii, endémica do Norte da costa este da América do Norte. Ambas as espécies são arbustos costeiros dióicos; o dimorfismo sexual é observável nas estruturas florais e na presença de frutos nas plantas femininas. Devido às diferenças nos custos da reprodução, machos e fêmeas têm necessidades fisiológicas e desempenhos diferentes. A hipótese principal que guia este trabalho é que diferenças fisiológicas e de desempenho, associadas ao sexo, dão origem a enviesamentos demográficos nas populações de Corema e influenciam as interações das plantas masculinas e femininas com os organismos que lhes estão associados. Foram estudadas três populações de C. album na costa oeste de Portugal (tanto na duna como no pinhal costeiro) e três populações de C. conradii na costa este do Canadá. A demografia das populações de C. album foi caracterizada para identificar enviesamentos relacionados com o sexo e foi avaliado um efeito de competição/facilitação das plantas de C. album sobre a flora associada. Investigou-se o ajustamento da maturação de frutos pelas plantas femininas no contexto da hipótese de ajustamento sequencial (Lloyd 1980). Investigaram-se as interações de plantas de Corema masculinas e femininas com organismos do solo para avaliar diferenças associadas ao sexo e ao tipo de habitat; estas incluíram as comunidades de nemátodes e de fungos endofíticos, particularmente micorrizas ericóides (ErM), associadas à rizosfera de ambas as espécies. Investigou-se uma possivel interação entre as comunidades de nemátodes e a colonização por ErM. Não se encontraram enviesamentos sistemáticos favoráveis aos machos nas populações de C. album estudadas e a maioria das parcelas amostradas apresentou uma distribuição espacial dos indivíduos de ambos os sexos completamente aleatória, sugerindo que as fêmeas são capazes compensar o esforço reprodutivo mais elevado que suportam. As plantas femininas de C. album apresentaram uma baixa produção de frutos em relação ao número de flores, mas infrutescências com mais frutos tinham drupas maiores e mais pesadas. Isto sugeriu, em conjunto com as condições ambientais dinâmicas e a falta de evidências de limitação de pólen, que os baixos números de frutos por infrutescência se devem ao ajustamento da produção e da maturação dos frutos à disponibilidade de recursos. Esta estratégia não só assegura a produção de um número ótimo de frutos em cada época reprodutiva, como minimiza os custos de reprodução acumulados ao longo de vários períodos reprodutivos, ao adaptar o esforço a cada evento de reprodução. Sendo a espécie vegetal dominante nas áreas amostradas, a cobertura por C. album teve um efeito prejudicial em todas as formas de vida vegetais (Raunkiær 1937), à excepção dos geófitos. Encontraram-se diferenças relacionadas com o sexo na composição e abundância das comunidades de nemátodes fitoparasitas (PPN) em ambas as espécies de Corema. O estado fenológico da planta influenciou significativamente a abundância de nemátodes de vida livre, géneros de PPN e os valores dos índices ecológicos das comunidades de nemátodes em C. album. Diferenças significativas relacionadas com o sexo da planta na comunidade de PPN associada a C. album e na abundância de três géneros de PPN (Criconema, Hemicriconemella e Meloidogyne) foram visíveis durante a época de frutificação, mas não durante a de floração, sugerindo que as interações com a comunidade de nemátodes dependem, não só do sexo da planta, mas também do seu estado fenológico. A comunidade de fungos endofíticos associada às raízes de Corema incluiu vários taxa: fungos que formam micorrizas ericóides, ecto-micorrizas e endófitos dark septate. Não se detetaram diferenças associadas ao sexo na composição nem na diversidade das comunidades de fungos endofíticos de qualquer das espécies de Corema, nem na percentagem de colonização das raízes de C. album por ErM; plantas que cresciam nas mesmas áreas apresentaram comunidades de endófitos semelhantes, independentemente do sexo da planta. A diversidade de endófitos e a colonização das raízes de C. album foram maiores durante a frutificação, mas não se detectou interação estatística entre o sexo da planta e o seu estado fenológico na frequência de colonização das raízes, o que indica que as ErM não respondem à variação na necessidade de recursos por parte de planta. As interações entre ErM e a comunidade de nemátodes foram detetadas apenas durante a época de frutificação, quando houve maior frequência de colonização por ErM. Corema album e C. conradii são os arbustos dominantes nas falésias e dunas costeiras que habitam. Estes ecossistemas são de particular importância já que representam a transição entre a orla costeira e as áreas interiores, protegendo as atividades produtivas do interior contra a salinidade, o vento e a erosão. Este trabalho apresenta as primeiras perspetivas sobre a ecologia da rizosfera destas duas espécies costeiras, enfatizando a importância de uma perspetiva integradora das interações entre organismos para a compreensão dos ecossistemas costeiros.