Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2005. / Within the Table Mountain National Park (TMNP), Western Cape, South Africa, various management practices have been undertaken in the removal of alien vegetation. While considerable success in the control of alien plants is evident from the removal of standing plants, it is not known if this effort has actually made any long-term difference in the effort to eliminate alien vegetation from the TMNP. This is because no coordinated effort has been made to assess the extent of the alien seed bank, nor the effect that clearing (including the use of fire) has on this seed store. This study investigates the extent of pre- and post-fire Acacia saligna seed banks under differing stand ages, differing clearing techniques and different habitats in the Cape Peninsula National Park. Firstly, the focus is on two alien plant management techniques: The first technique involves clearing and stacking of biomass for burning during winter (stack burn technique), the second technique involves burning of standing alien plants (standing/block burn technique) to decrease heat release at the surface. Secondly, the extent of Acacia species seed banks along the Silvermine River is also investigated with the aim of determining the extent of alien seed stores in this habitat and therefore the long-term restoration potential of the riparian corridor. The primary question addressed in the first study is: “Under what clearing technique will most of the alien seed bank be reduced?” The secondary question reads: “Is seed bank density and distribution directly related to age of dense infestation of the alien vegetation stand and habitat?” The primary question addressed in the second study is: “What is the vertical, lateral and longitudinal distribution and density of Acacia species seed banks along the Silvermine River?” The secondary question reads: “Is seed density and distribution influenced by above ground density of alien vegetation?” In both riparian and terrestrial systems, alien soil seed banks accumulate in high densities where aboveground alien Acacia vegetation is dense. Most of the seed occurs in the upper soil layer, but seed density decreases with depth with an exception of a high seed density at a low depth in one of the samples in the riparian system. Intense fires are most effective in reducing seed stores and removing aboveground alien vegetation in both riparian and terrestrial fynbos systems. After burns, both stack and stand burns have shown a significant decrease in seed density especially in the upper layers but there is still much seed that remained in the matrix area between stacks. The cooler winter burns resulted in less destructive, lower temperatures that aided higher seedling recruitment. Mature stands of Acacia saligna tend to have greater seed stores than immature stands and habitats with deep colluvial soils have a greater density and also greater vertical distribution of seeds. The vertical distribution of the riparian system differed from the fynbos terrestrial system in that seeds were found down to lower depths. Along the river, seed density also increased laterally with more seeds occurring in the terrrestrial sections than in the channel. Seed density increased with longitudinal distribution with more seeds occurring at the sites in the lower catchment than upper catchment. Managers should be aware that fire is needed to reduce the seed bank in both riparian and terrestrial fynbos systems. The cooler winter stack burns is the best option as it results in less destructive, lower temperatures that aids higher seedling recruitment. It is important to know the site history as age of dense infestation, number of fires and geology of site could influence seed bank density. In riparian systems the vertical distribution of seed is deeper than in the fynbos area. In order for clearing to be effective it is imperative that follow-up takes place and should be done prior to flowering to stop reseeding.

Student Number : 9202137P - MSc Dissertation - School of Animal, Plant and Environmental Studies - Faculty of Science / The Reconstruction and Development Programme’s Mpumalanga Working for Water Programme (WWP) has cleared exotic and commercial weed species from the riverine environment since 1994. This study serves as an assessment of the impact and modification caused as a result of invasion and the subsequent clearing of the exotic vegetation on flora in the riverine zone of the Sabie River Catchment. The experimental design compares the before and after clearing effects and includes altitude and invasion intensity variables. The investigations included: in situ soil seed banks, environmental modification, vegetation structure, species diversity and effectiveness of clearing. Clearing and invasion by exotic species altered soil chemical, physical and ground cover parameters. The extent of these modifications was dependent on the extent of invasion and clearing done within the community. Clearing of exotic species however, acted as an additional disturbance to that caused by invasion. Environmental modifications that occurred with clearing and invasion within the study were positively related to percentage soil organic matter, and ground cover (soil, litter, vegetation). Invasion by exotic species alters the vegetation structure, the extent of which was directly related to the invasion intensity. The main source of vegetation structure modification is attributed to tall growing exotic species such as Eucalyptus grandis and Solanum mauritianum. Both of these species dominated the indigenous vegetation, E. grandis by expanding the upper canopy and S. mauritianum by dominating the mid canopy. Clearing of invasive vegetation resulted in an additional disturbance proportional to the extent of invasion intensity. Invasion did not result in any large changes to the vegetation at low intensity but clearing at this intensity increased the disturbance and altered the vegetation structure. Soil seed banks were limited in the number of species and dominated by two exotic species. The soil seed bank of woody species related positively to the community species richness. The total soil seed bank density did not relate to invasion intensity or clearing thereof but propagules of individual species within the soil seed banks did. The seeds of the exotic species, Acacia mearnsii and S. mauritianum, illustrated burial as prerequisite for persistence in the soil seed bank. A. mearnsii and S. mauritianum seeds were found to have half-life’s of up to 25 years and 13 months respectively. The species richness and diversity varied only marginally because of invasion and clearing. Species alpha diversity increased with clearing due to weedy and pioneer species establishment. Beta diversity effectively highlights the species turnover with clearing and invasion. Success in eradication of exotic species had mixed results. Clearing of high invasion sites was effective but in lower invasion categories a number of exotic individuals were missed. Clearing effectiveness was good for certain species such as E. grandis and Pinus patula, but poor for others such as S. mauritianum. Coppicing is a significant issue for E. grandis and S. mauritianum. The persistence of individuals (coppicing & missed individuals) coupled with very large persistent seed banks has repercussions for the clearing programme, as it may prevent effective eradication. Initially the WWP has been successful in removing exotic vegetation, however there is a failure to address the regenerative properties of some exotic species. Unless a rigid schedule of follow up clearing treatments occurs, an even larger invasion problem could exist.

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2017-04-06T15:22:02Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_andres_antonio_monge_vargas.pdf: 823114 bytes, checksum: f67f9c364ef84bc1b73e7ab74ddaf68c (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-04-19T20:17:27Z (GMT) No. of bitstreams: 2 dissertacao_andres_antonio_monge_vargas.pdf: 823114 bytes, checksum: f67f9c364ef84bc1b73e7ab74ddaf68c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-04-19T20:18:36Z (GMT) No. of bitstreams: 2 dissertacao_andres_antonio_monge_vargas.pdf: 823114 bytes, checksum: f67f9c364ef84bc1b73e7ab74ddaf68c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-04-19T20:18:49Z (GMT). No. of bitstreams: 2 dissertacao_andres_antonio_monge_vargas.pdf: 823114 bytes, checksum: f67f9c364ef84bc1b73e7ab74ddaf68c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-08-04 / Sem bolsa / A buva (Conyza spp.) é uma planta daninha, disseminada em todo mundo, que ocorre em áreas agrícolas da América do Sul. Adaptada especialmente aos sistemas de semeadura direta, onde evoluiu junto com o uso de culturas geneticamente modificadas com resistência ao glifosato, originando biótipos resistentes a esse herbicida, agravando o problema de manejo e controle desta espécie. Diante disso, os objetivos da pesquisa foram: avaliar a dormência de buva, testando tratamentos pré-germinativos para superar a dormência das sementes em diferentes períodos de armazenamento; avaliar o efeito da temperatura de armazenamento na germinação e longevidade; e, determinar o efeito da profundidade de enterrio na longevidade do banco de sementes no solo. Para isso, foram conduzidos experimentos em campo e laboratório, utilizando-se sementes coletadas a partir de capítulos em fase final de maturação. As variáveis avaliadas, em percentagem (%), foram: primeira e segunda contagem de germinação, plântulas anormais, sementes: remanescentes, mortas, dormentes, viáveis e não viáveis. Os resultados demonstram que a semente de buva apresenta dormência primaria de tipo fisiológica, e que a embebição das sementes em água durante 24 horas ou o armazenamento a 25º C por 53 dias, são tratamentos eficientes para superar essa dormência. O enterrio da semente a 0,5 cm de profundidade, induzem as sementes a dormência secundária, quando armazenada a 10, 20 e 30º C, no entanto, quando armazenada a 20 e 30º C, a qualidade fisiológica é prejudicada. O banco de sementes de buva foi reduzido em 59 %, no período de um ano, ao mesmo tempo que o enterrio, independente da profundidade, podem induzir as sementes a dormência secundária. As sementes enterradas a maiores profundidades, apresentam longevidade e qualidade fisiológica superior. / Horseweed (Conyza spp.) is a worldwide disseminated weed, occurring in disseminated areas of South America. Specially adapted to no-till systems, where it evolved along with the use of genetically modified crops with glyphosate resistance, creating biotypes resistant to this herbicide, aggravating the problem of the management and control of this specie. Therefore, the research objectives were: to evaluate the horseweed seed dormancy, testing pre-germination treatments to overcome seed dormancy in different storage periods; to assess the effect of storage temperature on seed germination and longevity; and to determine the burial depth effect in soil seeds banks longevity. For this, field and laboratory experiments were conducted, using collected seeds from flowers in final maturation phase. The variables evaluated as a percentage (%) were: first and second count germination, adnormal seedlings, seeds: remnants, dead, hard, viable and non-viable. The results show that horseweed seed has primary physiological dormancy type, and soaking the seeds in water for 24 hours or storage at 25º C for 53 days are effective treatments to overcome this dormancy. The seed burial depth at 0,5 cm, induce secondary dormancy, when storage at 10, 20 and 30º C, however, at 20 and 30º C, physiological quality is affected. The horseweed seed bank was reduced by 59% in one year, while the burial, regardless of the depth, seeds can induce secondary dormancy. Seed burial at greater depths, have longevity and superior physiological quality.

Studies of seed dynamics and seedling establishment at the community level in savanna ecosystems are scant, particularly in the tropical savannas of Central Brazil. The Brazilian savannas (cerrado) have the largest diversity of plant species among Neotropical savannas. Cerrado vegetation exhibits consistent changes in tree density and tree size along shallow topographic gradients. Vegetation types differ from closed savannas with high tree density, and a nearly continuous canopy cover in the uppermost portions, to open savannas with scattered short trees in the low portions of the topographic gradients. Whether or not dynamics of seeds and seedlings of woody species are consistent with variations in tree density and tree canopy cover across the cerrado landscape has not been determined, but could potentially influence such spatial patterns of tree density and canopy cover. The main objective of this study was to evaluate seed dynamics (i.e., seed rain, soil seed banks, and seed characteristics) and seedling establishment of woody species in three major cerrado vegetation types (closed, intermediate and open savannas) which differ in tree canopy cover and tree height. These vegetation types are located along topographic gradients of approximately 30 m in elevation and 1000 m in length. I conducted field work from June 2005 to August 2008 at the Instituto Brasileiro de Geografia e Estatística (IBGE) reserve, a field experimental station located 35 Km south of Brasilia, Brazil (15˚ 56' S, 47˚ 63' W, altitude 1100 m). I established permanent plots in each of the three vegetation types to assess seed rain, seed limitation, seed predation, and seed removal. I also quantified density and composition of the soil seed bank in each vegetation type and studied seed characteristics (i.e., kind of dormancy, moisture content, longevity) of 14 common cerrado woody species. In the field, I quantified establishment of woody seedlings in fire-protected savannas as well as in accidentally burned and frequently burned savannas. In the greenhouse I performed experiments to evaluate the effect of litter cover and light level on seedling emergence of 9 common cerrado woody species. Finally, I evaluated the effect of pulses of heat on seed germination of 5 common cerrado woody species under controlled conditions. The overall results of this study show that regardless of tree canopy cover, cerrado vegetation types are limited in seeds and seedlings of woody species, but these limitations are higher in open than in closed savannas. Most woody species do not form persistent soil seed banks along cerrado vegetation types because their seeds are short-lived, predated and quickly removed from the ground. In addition, dispersal season and dormancy appear to control timing of germination at the onset of the rainy season to ensure survival of seedlings in the field. In the absence of fire, establishment of woody seedlings is higher in closed than in open savannas because canopy cover mitigates the stressful environmental conditions of open savannas and thus facilitates establishment of woody seedlings. As a result, closed savannas are likely to maintain higher density of woody elements over time than open savannas. In burned savannas, however, species composition of woody and herbaceous seedlings is significantly affected because establishment of seedlings of woody and herbaceous species decreases but vegetative reproduction increases. This dissertation study indicates that interactions of early life-history stages of woody species with environmental and disturbance factors appear to play a more significant role in maintaining woody cover variations along cerrado topographic gradients than previously recognized.

<p>Coastal plain ponds are an understudied and threatened wetland ecosystem with many unique environmental attributes. Research in these ponds can investigate species-environment relationships, while simultaneously providing ecosystem-specific information crucial to their continued conservation and management. This dissertation explores patterns in coastal plain pond vegetation composition and species-environment relationships across space, through time, and in the seed bank and standing vegetation.</p><p>In a two-year field study at 18 coastal plain ponds across the island of Martha's Vineyard, Massachusetts, I investigated species-environment relationships within and among ponds. I identified vegetation species presences and abundances within 1 m2 quadrats, which ran continuously along transects established perpendicular to the water's edge. Species data were analyzed against local and landscape-scale environmental data. I also conducted a one-year seed bank study in which sediments from four coastal plain ponds were incubated in growth chambers and composition was compared to the standing vegetation. One hundred and thirty-four plant species were identified during vegetation sampling and 38 species were identified from incubated sediments.</p><p>I found significant compositional change across space in response to environmental gradients, with patterns in species composition occurring at both local and landscape scales. Elevation was the only local factor strongly correlated with species composition. Significant landscape-scale environmental factors included surficial geology and pond water salinity. Species composition was significantly correlated with hydrologic regime in 2005 but not in 2006. Overall patterns in vegetation species composition and abundance were more closely related to landscape-scale environmental variables than to local environmental variables. </p><p>I also found that coastal plain ponds undergo significant compositional change from one year to the next. Interannual variability disproportionately affected certain ponds and quadrats more than others, highlighting patterns in the relationships between compositional change and environmental attributes. Specifically, ephemeral ponds, ponds located on the moraine, ponds with high specific conductance values, and quadrats located closer to the waterline exhibited greater compositional change from 2005 to 2006 than permanent ponds, ponds located on the outwash plain, ponds with low specific conductance values, and quadrats located further from the waterline. </p><p>Finally, I found that coastal plain ponds exhibit a low degree of similarity between composition in sediments and standing vegetation. More species were identified in the standing vegetation than in the seed bank, and in most cases average species richness per quadrat was higher in the standing vegetation than in the seed bank. Seed bank and standing vegetation samples from ponds with different surficial geology were compositionally distinct. Seed bank samples from permanent and ephemeral ponds were compositionally distinct whereas standing vegetation samples were not.</p> / Dissertation

[Truncated abstract] Weeds are a major limitation to agricultural and horticultural production and the main method of control is the use of herbicides. In addition to the resulting chemical pollution of the environment, the wide spread and continues use of herbicides have resulted in many weeds developing resistance to commonly used herbicides. This study investigated the potential of using green manures as a cultural method of control of weed invasion in agricultural fields. To understand the general mechanisms involved in the suppression of seed germination in green manure amended soils, seeds of crop species with little or no dormancy requirements were used in certain studies. Lettuce (Lactuca sativa) and cress (Lepidium sativum) seeds were sown to a sandy soil amended with green manures of lupin (Lupinus angustifolius), Brassica juncea, or oats (Avena sativa) to determine if the amendments affected seed germination and/or decay. It was hypothesised that the addition of plant material would increase the microbial activity of the soil thereby increasing seed decay, under laboratory and greenhouse conditions. Initial experiments used lettuce, cress and lupin seeds. Lettuce and cress are commonly used as standard test species for seed viability studies. Subsequent experiments used seeds of annual ryegrass (Lolium rigidum), silver grass (Vulpia bromoides), wild radish (Raphanus raphanistrum) and wild oat (Avena fatua) as these weed species are commonly found throughout agricultural regions in Western Australia. Amending the soil with lupin or Brassica green manure was established as treatments capable of developing environments suppressive to seed germination. Lupin residues as green manure showed the strongest inhibition of seed germination and seed decay. The decay of certain seeds was enhanced with changes to soil microbial activity, dissolved organic carbon and carbon and nitrogen amounts in lupin amended soil. Seeds of weed species were decayed in lupin amended soil, but showed varied degree of decay. Annual ryegrass and silver grass were severely decayed and wild oat and wild radish were less decayed, in lupin amended soil.

Zugl.: Freiburg (Breisgau), Univ., Diss.

xviii, 160 p. : ill. (some col.) / Salt marshes are intertidal communities dominated by halophytic vascular plants that are subjected periodically to tidal inundation. These species have developed various adaptations to this stress, including tolerances of fluctuating salinity, extended periods of inundation and intervals of anoxic conditions. The marshes are divided into zones of different plant communities based on species' tolerances of ambient estuarine conditions. Abiotic stresses change along the estuarine salinity gradient (marine to riverine), potentially altering development and composition of plant communities. Abiotic gradients associated with tides are not the only factors that contribute to development of plant community composition in salt marshes. Both negative (competition) and positive (facilitation) biological interactions are also important. Factors that influence community structure in salt marshes, particularly on the eastern North American seaboard, have been well studied. In contrast, salt marshes along the Oregon coast are smaller and more discrete and have received comparatively little attention. The community structure and seed bank composition of six marshes along an estuarine salinity gradient were evaluated. Four major community types dominated marshes that varied in the salinity of inundating tidal waters. Community types were relatively consistent throughout the estuary despite the distances between the marshes. Unlike the emergent plant communities, marsh seed bank composition was more similar within a marsh than within a community type. The low and high marsh community types were separated by a distinct boundary in the marine marshes. Although abiotic factors influence the physical separation of communities, competitive interactions commonly determine the upper limit of a species. In Metcalf marsh, however, the upper boundary for two dominant low marsh species was not determined by competition with the high marsh dominant species. Positive biotic interactions between seedlings and existing vegetation in a community are important factors in determining species distributions, particularly in stressful estuarine environments. In salt marshes, where abiotic stress can be harsh, presence of existing vegetation can ameliorate these conditions and enhance germination and seedling establishment. However, interaction between seedlings and the emergent marsh community was highly competitive, though germination of one species was enhanced in the presence of existing vegetation. This dissertation includes un-published co-authored material. / Committee in charge: Dr. Scott Bridgham, Chairperson; Dr. Richard Emlet, Advisor; Dr. Steven Rumrill, Member; Dr. Alan Shanks, Member; Dr. Gregory Retallack Outside Member

Arid Recovery, a fenced reserve free of feral predators in arid South Australia, has successfully reintroduced two critical weight range (CWR) mammals, greater bilbies (Macrotis lagotis) and burrowing bettongs (Bettongia lesueur) to facilitate the restoration of arid Australian ecosystems. This thesis evaluates the ecological roles of these reintroduced species and their relationship to ecosystem functioning and the restoration of these ecosystems. Surveys of foraging diggings and soil seed banks, and dietary analysis were used to measure impacts of these species on three main habitats within the Reserve. The results showed that bilbies and bettongs have three major roles in ecosystem functioning: consumers, ecosystem engineers, and dispersers of seeds and fungi. Both bilbies and bettongs were omnivorous, though their diets were distinctly different, with the bilbies focused more on invertebrates and seeds, while the bettongs consumed a greater proportion of coarser plant materials. The seed portion of the diets of both species during 2003-04 differed from a similar study three years previously, shortly after the animals had been reintroduced to Arid Recovery in 2000- 01. During 2003-04, the bilbies consumed a lower proportion of seeds of species of grasses and more of forbs, while seed consumption by bettongs narrowed to be almost exclusively the seeds of shrubs. The number of bilby and bettong diggings varied significantly both spatially and temporally, with averages of 7,530 ± 820 diggings ha-1 in Dunes, 10,560 ± 980 diggings ha-1 in Mulga, and 7,120 ± 610 diggings ha-1 in Swale. This resulted in an average of 2 to 3% disturbance of soil surface area, which is similar to or higher than reported for other Australian or overseas semi-fossorial species. The temporal variation in rates of digging was correlated with minimum daily temperatures and rainfall but not moonlight. This variation was also correlated with counts of bilby but not bettong tracks, suggesting that the temporal variability of diggings was related to levels of bilby activity. The persistence of bilby and bettong diggings differed between the three habitat types, with the majority of the diggings in the Mulga (94%) and Swale (87%) persisting for over 12 months, while Dune diggings filled much faster, with only 15% persisting over 12 months. These diggings were shown to accumulate and bury seeds and litter, and, under some conditions, enhance germination. The seeds of two plant species, the annual grass, Dactyloctenium radulans, and the shrub, Enchylaena tomentosa, germinated from bilby faecal pellets, and over a third of bilby faecal pellets contained fungal spores. Therefore bilbies have the potential to be dispersers of both seeds and fungi. All three major roles of the bilbies and bettongs in ecosystem functioning (consumers, ecosystem engineers, and dispersers of seeds and fungi) have the potential to affect the flows of organic, soil and water resources, and therefore vegetation structure and overall productivity. Soil seed bank densities differed between areas with and without bilbies and bettongs. However, the heterogeneity of the system made it difficult to confidently relate these differences to any particular effects of the bilbies and bettongs. Both bilbies and bettongs were able to locate and dig seeds buried 20 cm deep, and the caches of seed-harvester ants. Experiments showed that in areas of high digging density, 71 to 94% of seed rain accumulated and became buried in diggings. Since bilbies and bettongs have the potential to use buried seed resources, they have the potential to significantly affect soil seed banks through their consumption of seeds, redistribution of seeds through their digging activities and their interactions with other granivorous species. This study is a first step towards understanding the roles of reintroducing CWR mammals to arid ecosystems. Possible longer term effects of these reintroductions will depend on suitable regulation of animal numbers, and climatic patterns, as restorative effects of diggings would be greatest during periods of good rainfall, whereas droughts would slow restorative processes. Although the results of this research are unique for Arid Recovery, the principles of evaluating all major ecological roles of reintroduced species and their interactions with their environment could provide guidance for other reintroductions. These interactions are complex and would require longer-term studies over a range of conditions and locations to further understand the role of reintroducing CWR mammals to ecological restoration. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1348600 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

Arid Recovery, a fenced reserve free of feral predators in arid South Australia, has successfully reintroduced two critical weight range (CWR) mammals, greater bilbies (Macrotis lagotis) and burrowing bettongs (Bettongia lesueur) to facilitate the restoration of arid Australian ecosystems. This thesis evaluates the ecological roles of these reintroduced species and their relationship to ecosystem functioning and the restoration of these ecosystems. Surveys of foraging diggings and soil seed banks, and dietary analysis were used to measure impacts of these species on three main habitats within the Reserve. The results showed that bilbies and bettongs have three major roles in ecosystem functioning: consumers, ecosystem engineers, and dispersers of seeds and fungi. Both bilbies and bettongs were omnivorous, though their diets were distinctly different, with the bilbies focused more on invertebrates and seeds, while the bettongs consumed a greater proportion of coarser plant materials. The seed portion of the diets of both species during 2003-04 differed from a similar study three years previously, shortly after the animals had been reintroduced to Arid Recovery in 2000- 01. During 2003-04, the bilbies consumed a lower proportion of seeds of species of grasses and more of forbs, while seed consumption by bettongs narrowed to be almost exclusively the seeds of shrubs. The number of bilby and bettong diggings varied significantly both spatially and temporally, with averages of 7,530 ± 820 diggings ha-1 in Dunes, 10,560 ± 980 diggings ha-1 in Mulga, and 7,120 ± 610 diggings ha-1 in Swale. This resulted in an average of 2 to 3% disturbance of soil surface area, which is similar to or higher than reported for other Australian or overseas semi-fossorial species. The temporal variation in rates of digging was correlated with minimum daily temperatures and rainfall but not moonlight. This variation was also correlated with counts of bilby but not bettong tracks, suggesting that the temporal variability of diggings was related to levels of bilby activity. The persistence of bilby and bettong diggings differed between the three habitat types, with the majority of the diggings in the Mulga (94%) and Swale (87%) persisting for over 12 months, while Dune diggings filled much faster, with only 15% persisting over 12 months. These diggings were shown to accumulate and bury seeds and litter, and, under some conditions, enhance germination. The seeds of two plant species, the annual grass, Dactyloctenium radulans, and the shrub, Enchylaena tomentosa, germinated from bilby faecal pellets, and over a third of bilby faecal pellets contained fungal spores. Therefore bilbies have the potential to be dispersers of both seeds and fungi. All three major roles of the bilbies and bettongs in ecosystem functioning (consumers, ecosystem engineers, and dispersers of seeds and fungi) have the potential to affect the flows of organic, soil and water resources, and therefore vegetation structure and overall productivity. Soil seed bank densities differed between areas with and without bilbies and bettongs. However, the heterogeneity of the system made it difficult to confidently relate these differences to any particular effects of the bilbies and bettongs. Both bilbies and bettongs were able to locate and dig seeds buried 20 cm deep, and the caches of seed-harvester ants. Experiments showed that in areas of high digging density, 71 to 94% of seed rain accumulated and became buried in diggings. Since bilbies and bettongs have the potential to use buried seed resources, they have the potential to significantly affect soil seed banks through their consumption of seeds, redistribution of seeds through their digging activities and their interactions with other granivorous species. This study is a first step towards understanding the roles of reintroducing CWR mammals to arid ecosystems. Possible longer term effects of these reintroductions will depend on suitable regulation of animal numbers, and climatic patterns, as restorative effects of diggings would be greatest during periods of good rainfall, whereas droughts would slow restorative processes. Although the results of this research are unique for Arid Recovery, the principles of evaluating all major ecological roles of reintroduced species and their interactions with their environment could provide guidance for other reintroductions. These interactions are complex and would require longer-term studies over a range of conditions and locations to further understand the role of reintroducing CWR mammals to ecological restoration. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1348600 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009