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Joint-head grass (Arthraxon hispidus) is a widespread nonindigenous plant species in the eastern United States. It is observed forming large monodominant patches that impact native and managed grassland systems. With such little understanding of its foundational biology or ecological impacts, leaving land managers desperate for effective control measures to manage A. hispidus invasion. We conducted a series of complementary experiments on six populations of A. hispidus to better understand how environmental factors affect seed germination. Germination is a critical life stage that allows a species to disperse. Freshly harvested seeds germinated effectively within 14 days of imbibition in the dark at 23°C, exhibiting little to no dormancy or influence by light. A pH range of 5 - 10 resulted in ≥ 80% germination, suggesting that pH will not limit colonization in other portions of the United States. Arthaxon hispidus was tolerant to abiotic stressors such as salinity and osmotic potential. The concentration required to limit germination to 50% (LD50) in the populations tested surpassed soil salinity found in the contiguous United States and some tidal systems (Frederick, MD = 354; Lincoln, MO = 354; Williamsburg, VA = 298 mM NaCl). While drought adversely affects A. hispidus germination, the LD50 occurred in moderate to more severe osmotic potentials (Frederick, MD = -0.67; Lincoln, MO = -0.37; Williamsburg, VA = -0.25 MPa) making A. hispidus expansion more likely in wetter years and regions. Constant temperature treatments resulted in germination percentages across a range of temperatures (8 - 37°C), and A. hispidus is well distributed in several major temperature regimes found in the United States. Finally, emergence greatly decreased with burial depth. Emergence occurred at ≥ 43% at 1 - 2 cm, decreasing to 5% at 6 cm, and 0% at 8-cm depths. With adequate soil moisture, a broad range of germination temperatures, and a decreased emergence rate with depth, we believe A. hispidus is unlikely to develop a seed bank. These initial studies on A. hispidus' germination posit a broad range of environmental tolerances; although, it may be limited by other life stages. / Master of Science / Joint-head grass is a non-native invasive plant species commonly found in the eastern United States. It is observed growing in large patches that negatively affect the environment. These effects can include decreasing biodiversity or lowering forage availability which negatively can impact cattle production. To better understand the basic biology of joint-head grass, we decided to harvest seeds to study from several populations in the United States. We tested differences in the populations by examining the different environmental effects on joint-head grass germination. Germination is a critical life stage of invasive plants; therefore, we developed complementary experiments to test the effects of the environment on seed germination. We've determined that germination occurs effectively under the effect of several environmental stressors. Germination occurred under salty (NaCl) conditions which may allow it to establish in tidal systems where brackish water is present. We've also determined that germination occurs effectively ( ≥ 80%) at a pH range from 5 - 10. This will allow joint-head grass to germinate in more basic soils commonly found in the western part of the United States. Further, we tested the moisture requirements for germination to occur, and we've found that it is tolerant to moderate to more severe drought conditions. Joint-head grass is also capable of germinating across a range of temperatures (8-37°C). The United States has well-distributed rainfall and suitable temperatures in large portions of the country. We believe the climate of the United States is well-suited for joint-head grass establishment, and that it may spread more frequently in years with higher precipitation during the growing season. This species potentially poses a threat to both our natural and agricultural systems.

Since the 1970s, the institution of fire management has been in a frustrated transition from fire suppression and control to ecologically informed fire management. Administrative boundaries, professional specializations and organizational incentives and funding mechanisms have stalled the adoption of landscape scale ecological fire restoration as a guiding paradigm. Using a case study approach, this dissertation examines the potential of a multi-scalar collaborative network, the US Fire Learning Network (FLN), to catalyze the changes necessary to overcome the frustrated transition. Established in 2002 in an agreement between the USDA Forest Service, The Nature Conservancy, and the US Department of Interior, the FLN operates at landscape, regional and national scales. In this multi-scalar context, the network utilizes planning technologies, communication modalities, and interpersonal interaction to link participants at each scale and motivate them to enhance their collaborative ecological restoration planning capacities. The network directly addresses the challenges of the frustrated transition by enabling practitioners to collaborate across administrative and disciplinary boundaries, develop expertise in ecological fire restoration planning and management, and to inform policy changes at the federal level that can create new incentives and funding mechanisms that support landscape scale ecological restoration. While institutional transformation has yet to occur, the FLN sets the stage to address the core challenges that fire management practitioners and organizations face as they engage in landscape scale ecological fire restoration. This work provides theoretical and practical insights to collaborative planning research by introducing new forms of collaborative practice, describing how collaborative planning can be conducted across multiple scales simultaneously, and establishing how multi-scalar collaborative networks may be able to catalyze institutional change necessary to respond to complex cross scalar environmental problems. / Ph. D.

A direct consequence of disorganized human population growth and the indiscriminate use of natural resources are the reduction of area and the fragmentation of native ecosystems, as they transform into agricultural areas. In this scenario, agroforestry systems (AFS) may be an alternative to reconcile restoration, conservation and local agricultural production. However, there is a diversity of AFS, and its use as a forest restoration strategy is still uncertain, mainly because we lack evaluations based on ecological indicators from those systems. Thus, we compared ecological indicators measured in a coffee agroforestry system in the Pontal do Paranapanema with those inform conventional restoration plantings of the same age and with regional reference ecosystems. We measured natural regeneration density and richness; canopy cover by native species and aboveground biomass and compared among sites using an ANOVA, followed by Tukey\'s test for mean comparison. Aiming to understand the factors influencing the ecological indicators of forest restoration in coffee AFS, we performed generalized linear models (GLM) using density of coffee and native trees, biomass, percentage of animal-dispersed trees, distance to the nearest forest remnant and richness of tree species as predictor variables and percentage of canopy cover and density and richness of natural regeneration as response variables. The reference forests had the highest values for forest structure indicators, followed by AFS and finally by the conventional restoration plantings. However, we found a greater diversity of tree species planted in the AFS and a natural regeneration similar to that found in the reference ecosystems. Despite coffee density in the AFS negatively influencing natural regeneration, the coffee AFS had greater ecological performance than the conventional restoration, being a viable alternative for forest restoration. We conclude that AFS with coffee and native tree species play an important ecological role in the FLR in Pontal do Paranapanema, reconciling productivity with forest restoration. / Um reflexo direto do crescimento desordenado da população humana e das atividades antrópicas é a diminuição e a fragmentação da área ocupada por ecossistemas nativos e sua substituição por áreas agrícolas. Neste cenário, os sistemas agroflorestais (SAF) podem ser uma alternativa para conciliar restauração, conservação e produção agrícola local. No entanto, tendo em vista a diversidade de SAFs, sua adoção como estratégia de restauração florestal ainda carece de estudos que avaliem os níveis de indicadores ecológicos de cada sistema. Neste sentido, comparamos os indicadores ecológicos de sistemas agroflorestais com café e espécies arbóreas nativas no Pontal do Paranapanema, com os de plantios convencionais de restauração florestal de mesma idade (12-15 anos) e ecossistemas de referência regionais. Medimos a densidade e a riqueza da regeneração natural, a cobertura do solo por espécies nativas e a biomassa acima do solo e as comparamos entre as áreas pela análise de variância ANOVA seguida da comparação de médias pelo teste de Tukey. Buscando compreender os fatores que influenciam os indicadores ecológicos da restauração florestal no SAF, analisamos modelos lineares generalizados, tendo biomassa, porcentagem de árvores zoocóricas, distância do remanescente florestal mais próximo, densidades de café, riqueza e densidade de árvores nativas como variáveis preditoras, e porcentagem de cobertura do dossel, densidade e riqueza da regeneração natural como variáveis respostas. As florestas de referência tiveram os maiores valores para indicadores de estrutura florestal, seguidas pelos SAFs e pelos plantios convencionais de restauração florestal. Entretanto, encontramos elevada diversidade de espécies arbóreas nos SAFs e valores próximos aos das florestas de referência para a diversidade da regeneração natural. Embora a densidade de plantas de café influencie negativamente a regeneração natural, os SAFs apresentaram um melhor desempenho ecológico que as áreas de restauração convencional, correspondendo à uma alternativa viável para restauração florestal. Desta forma, concluímos que os sistemas agroflorestais estudados desempenham um papel ecológico importante na restauração da paisagem florestal no Pontal do Paranapanema, conciliando produção com restauração florestal.

Master of Science / Division of Biology / John M. Blair / Temperate grasslands are among the most threatened biomes in the world, with the largest historical losses due to conversion to agricultural land. While much of this biome has already been converted, there is concern the last remaining remnants in North America will be converted in response to increasing demand for crops used for ethanol production. Thus, restoring grasslands post-anthropogenic disturbance is increasingly important for conserving grassland biodiversity. Two major challenges for prairie restorations are establishing the many subdominant and rarer species found in native prairie, and offsetting the typical decline in richness and diversity over time as restorations age. Repeated seed addition of targeted species is commonly used to override low and declining plant richness and diversity. While this is generally effective early in restoration (i.e., as communities are establishing), its effectiveness in later stages (i.e., when established communities are often losing diversity) remains unknown. I investigated plant community responses to combinations of resource manipulations and disturbances coupled with a seed addition in a 15-yr old restored grassland to test the hypothesis that spatial resource heterogeneity increases the rate of colonization into established prairie restoration communities. Seeds were added to a long-term restoration experiment involving soil depth manipulations (deep, shallow) crossed with nutrient manipulations (reduced N, ambient N, enriched N). Seedling emergence was generally low and only 8 of the 14 forb species added were detected in the first growing season. I found no effect of increased resource heterogeneity on the abundance or richness of seedlings. There was a significant nutrient effect (p<0.1, α=0.1) on seedling abundance, with higher emergence in the enriched N than the ambient N treatment. I also found unexpected nutrient effects on richness, diversity and Mean C (Mean C = Σ CoCi*Ai, where CoC=Coefficient of Conservatism and A=relative abundance of the ith species). All values, except Mean C, were higher in the enriched N treatment than in either the reduced or ambient N treatments. Mean C was lowest in the enriched N treatment, and highest in the whole-plot control, suggesting that the majority of species contributing to higher richness and diversity in the enriched N treatment were “weedier” species. In a separate experiment, I found no effect of small-scale disturbances (aboveground biomass removal or soil disturbance) on seedling abundance or seedling richness. I did find a marginal effect of disturbance type on seedling richness (p=0.11, α=0.1), with higher seedling richness in the soil disturbance than the aboveground biomass removal treatment. I did not find any disturbance effects on community response variables. These results indicate that recruitment from seed additions into well-established restored communities is relatively low in the first year following a seed addition, regardless of resource availability and heterogeneity. Follow-up studies to determine recruitment rates in subsequent years are needed to elucidate whether recruitment responses are driven more by individual species differences or by environmental mechanisms.

Thesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / Dispersal plays an essential role in determining the distribution of populations of species, especially species expanding their ranges. Two disciplines are concerned with gaining understanding of spread of species, namely restoration ecology and invasion biology. Con- ceptual understanding of dispersal, its mechanisms and its management is essential to both disciplines. Nevertheless, the disciplines have quite opposite objectives: in restoration ecol- ogy, spread of indigenous species into transformed landscapes is promoted, while invasion biology aims to prevent the (further) spread of alien species into pristine or restored habi- tats. Despite these two opposite objectives of facilitating spread and preventing spread of their respective target species, these disciplines have essentially the same requirements in terms of information needed for restoration. In this thesis, I will present two modelling studies—one looking at the impact of two different seed-feeding alien control agents on the spread of Hakea sericea, the other investigating the recolonisation by Dicerothamnus rhinocerotis of an old field dominated by Cynodon dactylon. Based on these studies, I will draw conclusions for the management in each case. In a second step, I will compare these two seemingly-different studies and draw conclusions on how these two disciplines can learn from each other, and how conclusions drawn and management recommendations developed for the one discipline can be translated for the other. The invasion biology study concluded that seed-feeding biocontrol agents do have a considerable impact on the velocity of the spread of the target species. In addition, management recommendations included the possibility of substituting seed-feeding biocontrol agents with an increased fire frequency where the negative impact on natural vegetation, on the site invaded by the target species, is acceptable. The restoration study concluded that the main impact on the velocity of spread, and the speed of the return of the shrub species onto the old fields, is the availability of micro-sites. A sensitivity analysis showed the even a slight change from 1% to 2% increases the velocity and pattern of spread dramatically. The other parameters playing an important role are the mean rate of establishment and the time span between

Food forestry has grown in its popularity in Canada, the United States and the United Kingdom, which it has not been traditionally practiced before, for its potential to produce healthy food, to create habitat for wildlife species, to reconnect people with nature and to provide various ecosystem services such as carbon storage. Diverse food forest projects are conceived from urban food initiatives to integrated conservation and restoration planning. Currently, the Galiano Conservancy Association is creating two food forests in the heart of a mature Coastal Douglas-fir landscape on Galiano Island, British Columbia, which is protected under a conservation covenant, in pursuit of sustainable food production, education and contribution to ecological restoration and conservation efforts. To investigate the relationships between emerging food forestry and ecological restoration and to identify key indicators to measure best practices of food forestry in the context of ecological restoration, I conducted 16 semi-structured interviews with food forestry and ecological restoration experts. In addition, I conducted a workshop with the Conservancy stakeholders to develop a comprehensive and systematic monitoring framework for their food forest projects. My studies suggest that restoration principles and resilience thinking can provide guidelines for restorative food forestry. Food forestry may serve as an innovative restoration tool to restore urban landscapes where lack significant opportunities for conventional restoration. A generic monitoring framework for food forestry could be adapted by other projects, yet this will require the process of defining goals and objectives of a given project and assessing landscape contexts and the organization’s capacity to monitor. / Graduate / soph.park@yahoo.ca

There is growing awareness about the value of preserving and restoring floral-rich habitats for the benefit of pollinators, especially native bees. The increasing demand for native plants in pollinator habitat restoration and other ecological landscaping applications, combined with the desire for more robust and predictable plant habits, have led to the selection and breeding of native cultivars. Yet, little is known about how these cultivated varieties differ from the native species in their ability to attract and support pollinators. I compared flower visitation by all insect pollinators to 12 native herbaceous plant species and 14 native cultivars in a replicated field experiment at two sites over two years. I classified insect pollinators during visual field observations into seven taxonomic and functional groups. I found seven native species to be visited significantly more frequently by all insect pollinators (combined) than their cultivars, four were visited equally, and one native cultivar was visited more frequently than the native species. Bees (both native and non-native) and moths/butterflies exhibited similar preferences, whereas flies showed no preference between the native species and the native cultivar. Our study shows that many insect pollinators prefer to forage on native species over cultivated varieties of the native species, but not always, and not exclusively. Some native cultivars may be comparable substitions for native species in pollinator habitat restoration projects, but all cultivars should be evaluated on an individual basis. Plant selection is integral to the value and success of pollinator habitat restorations, yet there is little consistency and overlap in pollinator planting recommendations and very little empirical data to support plant choice. Non peer-reviewed pollinator plant lists are widely available and are often region-specific, but they are typically based on anecdotal rather than empirical data and lack in specificity. To help close the gap between anecdotal and empirical data, and between practice and research, I reviewed the published literature on plant selection for pollinator habitat restoration. I explicitly reviewed and compared the value of native plant species, near-natives, non-natives and native cultivars. From there, I identified gaps in the literature that are most needed in practice and recommended basic strategies for practitioners to navigate plant lists and choose the best plants for a site's success.

A mineração causa graves impactos ambientais, sendo o solo um dos componentes do meio físico mais vulnerável durante a exploração das jazidas. O ciclo do N tem sido bastante estudado, entretanto, pouco se sabe sobre a trajetória de recuperação da sua ciclagem em florestas restauradas após a mineração de bauxita. O objetivo foi investigar de que maneira o processo de restauração florestal em área minerada para extração de bauxita interfere na ciclagem do nitrogênio no sistema solo-planta-serapilheira. Para tanto, foram mensurados nesses compartimentos a disponibilidade de N, suas razões N:P e a abundância natural do isótopo estável de N (?15N). As hipóteses propostas foram: \"A restauração florestal, conduzida pelo uso de técnicas de engenharia ecológica, plantio de espécies arbóreas nativas e adição de topsoil é suficiente para aumentar a disponibilidade de N no ecossistema\", e \"Áreas mineradas em processo de restauração florestal, com o avanço da sucessão ecológica, podem desenvolver uma dinâmica na ciclagem de N próxima ao ecossistema de referência, apresentando valores de concentrações desse nutriente nos seus compartimentos (solo-planta-serapilheira) semelhantes a esse ecossistema\". O estudo foi conduzido no município de Poços de Caldas/MG, sendo considerados três tratamentos: floresta nativa, área restaurada há aproximadamente 06 anos e área restaurada há 24 anos, com seis repetições para cada. O delineamento utilizado foi o inteiramente casualizado, no esquema de parcelas subdivididas. O ciclo do N não foi recuperado nas florestas em restauração. Entretanto, há uma tendência de a ciclagem desse elemento assemelhar-se a da floresta nativa, conforme o avanço da sucessão ecológica. Deste modo, ambas as hipóteses propostas foram confirmadas, sendo a utilização de técnicas de engenharia ecológica, plantio adensado de espécies nativas e a adição de topsoil, os principais responsáveis pelos resultados / Mining causes serious environmental impacts and the soil is the most vulnerable component of the physical environment during the exploitation of deposits. The N cycle has been extensively studied, however, little is known about the recovery trend of its cycling in forests restored after bauxite mining. The aim was to investigate how the forest restoration process in bauxite mined area interferes in the nitrogen cycling in the soil-plant-litter system. Therefore, we measured the availability of N, the N:P ratios and the natural abundance of N stable isotope (?15N) in these compartments. The hypotheses proposed were: \"Forest restoration, driven by the use of ecological engineering techniques, planting of native tree species and addition of topsoil is sufficient to increase the availability of N in the ecosystem\", and \"Mined areas in forest restoration process, with the advancement of ecological succession, can develop a dynamics in N cycling resembling to that of the reference ecosystem, presenting values of concentrations of this nutrient in their compartments (soil-plant-litter) similar to this ecosystem. The study was conducted in Poços de Caldas county, Minas Gerais state, Brazil, considering three treatments: native forest, area restored for approximately 06 years and a restored area for 24 years with six repetitions for each. The design was completely randomized in a split plot. The N cycle has not been recovered in forest restoration. However, there is a tendency of N cycling resemble that of the native forest as the advancement of ecological succession. Thus, both hypotheses were confirmed, and the use of ecological engineering techniques, dense planting of native species and the addition of topsoil, were the main responsible for these results

A reparação de danos provocados pelo homem aos ecossistemas não é recente no Brasil. Plantações florestais têm sido estabelecidas desde o século XIX sem, no entanto, até recentemente, terem vínculos estreitos com concepções teóricas, sendo executadas normalmente como uma prática de plantio de mudas, com objetivos muito específicos, como controle de erosão, estabilização de taludes, melhoria visual, entre outros. Com o desenvolvimento dos conceitos e teorias ecológicos, sobretudo nos últimos cinqüenta anos, os programas de manejo e restauração florestal têm deixado de ser meras aplicações de práticas agronômicas e silviculturais, para buscar a reconstrução de interações ecológicas da comunidade, ou seja, os projetos de restauração estão deixando de ser o plantio de um amontoado de indivíduos e passando a considerar o potencial de auto-regeneração do ambiente. Este trabalho foi desenvolvido em um sítio degradado da Reserva Legal do aeroporto municipal de Registro (SP), cidade situada no Vale do Ribeira, com o objetivo de avaliar o potencial da transferência de banco de propágulos alóctone em recuperar áreas degradadas. O uso de banco de propágulos como método de recuperação de áreas degradadas é uma prática já bastante utilizada para a recuperação de áreas mineradas em todo o mundo. Nesses casos, o banco é comumente espalhado na área total, normalmente com grande espessura (20 - 50 cm). Neste trabalho foi testada a deposição do banco de propágulos em sulcos, partindo-se da premissa que esta técnica pode permitir que um mesmo volume de banco seja capaz de recuperar uma área degradada maior, aumentando seu rendimento. Assim, na área experimental foi testado o potencial regenerativo do banco de propágulos através de quatro tratamentos: testemunha (Controle), Calcário (Ca), Calcário + Nitrogênio inicial (Ca+Ni) e Calcário + Nitrogênio em cobertura (Ca+Nc). Cada tratamento foi alocado em um sulco de dimensões 0,3m X 0,3m X 20,0m (1,8 m³), e repetido quatro vezes, totalizando 16 sulcos (28,8 m³). A coleta da serapilheira e do solo até uma profundidade de 20 cm, que corresponde ao banco de propágulos aqui estudado, foi feita em 12 parcelas amostrais de dimensão 3,0mX3,0mX0,2m (1,8m³), distribuídas a esmo nas manchas da floresta classificadas em estágios médio e avançado de regeneração, na faixa de floresta condenada à supressão. O solo e a serapilheira da parcela foram revolvidos com enxada. Este material foi acondicionado em sacos de ráfia de 100L. Entretanto, cada saco continha apenas 60L (~70Kg). Para obedecer este padrão, utilizou-se uma lata de tinta de 18L, estabelecendo-se 3,3 latas por saco. Este volume estabeleceu uma média de 21,33 sacos por parcela. Foi coletado um total de 256 sacos. Estes sacos foram distribuídos em 16 sulcos, com 16 sacos por sulco. Em um ano, iniciado em Setembro de 2006, foram coletados dados de emergência, crescimento, recrutamento e mortalidade dos indivíduos arbustivo-arbóreos. Durante os 12 meses de monitoramento, surgiram 538 indivíduos de 40 espécies, apenas desses hábitos, em uma área de 96m². Aos 12 meses, 409 indivíduos estavam vivos. O tratamento Controle foi aquele que apresentou as maiores quantidades de indivíduos e espécies, apresentou menor número de 7 indivíduos mortos e menores taxas de crescimento. Os demais tratamentos indicaram que os insumos favoreceram apenas o crescimento, tendo havido efeito neutro ou negativo sobre os outros parâmetros avaliados. / The relief of the human damage caused on natural ecosystems is not recent in Brazil. Forest plantations have been established since XIX century, although only recently it have been based on a conceptual framework; before that plantations were planned to attend specific purposes, such as eroding control, embankment slopes, visual improvement, among others. The development of ecological concepts and theories, mostly in the last 50 years, promoted relevant changes on restoration projects, which evolved to consider the environment\'s self-regeneration potential. This study was developed at a degraded site within the Legal Reserve of the airport of Registro, SP, located at Ribeira Valley. The main purpose was to evaluate the alochtonous seed bank transference potential as a restoration technique. Transference of alochtonous propagules is an usual technique for mining areas restoration around the world. In these cases the propagules bank (topsoil) is usually spread as a thick layer (20 - 50cm) over the target area. Here the topsoil was spread over sulcos (arroyos, wales), accepting the idea that with this technique a certain amount of topsoil may recover a larger area, enhancing its income/output. Thus, the regenerative potential of the topsoil was tested over four experimental treatments: attester (Control), Calcareous/Limestone (Ca), initial Calcareous + Nitrogen (Ca+Ni) and on surface Calcareous + Nitrogen (Ca+Nc). Each treatment was allocated into 0.3m x 0.3m x 20m (1.8m3) furrows and repeated four times, in a total of 16 furrows (28.8m3). Topsoil was collected at a 20cm depth, sampled by twelve 3.0m x 3.0m x 0.2m (1.8m2) plots, distributed without direction within secondary forest remnants in late sucessional stages, in the logged area. Topsoil was removed with hoe and bagged into 100L raffia bags. Therefore, each bag was fulfilled with 60L (~70Kg) only. To follow the pattern, 18L paint tin box were used to keep an average number of 3,3 paint tin box per bag. This volume correspond to an average of 21.33 sacos per plot. From September 2006 to September 2007, emergence, growth, recruitment and mortality were monitored. A total of 538 individuals (shrubs and trees) of 40 species were recorded, in a total area of 96m2. After 12 twelve months 409 individuals survived. Control treatment presented the highest individuals and species quantities, the lowest growth rates and mortality. The other treatments revealed that fertilizers indulge growth, with neutral or negative effects over demais evaluated parameters.