Casos reportados de buva com resistência ao glyphosate têm aumentado, ano após ano, a importância dessa planta daninha no cenário agrícola brasileiro. Com o intuito de entender alguns aspectos de sua biologia que resultem em manejo mais adequado, os objetivos deste trabalho foram: (i) identificar os períodos do ano em que ocorrem os maiores fluxos de emergência da buva e analisar seu crescimento e desenvolvimento em dois ambientes agrícolas distintos; (ii) avaliar os efeitos da cobertura vegetal e umidade em sua germinação e emergência; (iii) construir curvas de dose-resposta de um biótipo de Conyza bonariensis resistente ao glyphosate para herbicidas alternativos e (iv) avaliar as opções de manejo químico desse biótipo após o corte e rebrota. Para esses objetivos, experimentos foram conduzidos em campo e casa-de-vegetação nos municípios de Santa Cruz das Palmeiras, SP (SCP) e Não-Me-Toque, RS (NMT), entre maio de 2010 a maio de 2012. Em condições de campo, observou-se em SCP que a emergência da buva ocorre de forma escalonada, sendo mais concentrada no final do verão e início da primavera e a precipitação e a presença de pouca cobertura vegetal no solo parecem exercer mais influência que a temperatura. Em NMT, o fluxo de emergência é mais concentrado no inverno, em que a precipitação não é fator limitante, sendo a germinação e emergência favorecidas por temperaturas mais baixas. Nos dois locais, plantas que germinam na época mais fria do ano (julho) apresentam desenvolvimento inicial mais lento, com acúmulo de biomassa mais intenso e concentrado em torno dos 90-104 dias após a semeadura (DAS); plantas que germinam na primavera (setembro) também apresentam desenvolvimento inicial lento, porém seu crescimento é mais distribuído ao longo do tempo, com os picos de acúmulo aos 80-90 DAS. Em condições de casa-de-vegetação, a disponibilidade hídrica do solo foi mais importante para a emergência de plântulas de buva que a quantidade de cobertura vegetal (palha). Em solo úmido, menores quantidades de palha favorecem a emergência da buva em relação ao solo descoberto. Quantidades maiores de palha promovem supressão de sua emergência. A resistência ao glyphosate foi confirmada para o biótipo de C. bonariensis, coletado em SCP (biótipo B2) e a eficiência dos herbicidas alternativos foi diferente em função dos estádios de desenvolvimento desse biótipo no momento da aplicação. Os herbicidas metsulfuron, diclosulam, 2,4-D, dicamba, atrazine, glufosinate e paraquat foram os mais consistentes no controle do biótipo resistente, sendo que, no estádio mais avançado, a associação com glyphosate agregou no controle para metsulfuron, diclosulam e 2,4-D. Após o corte, controle mais eficiente da rebrota (biótipo B2) foi obtido quando a aplicação ocorreu no mesmo dia do corte que 7 dias depois e os tratamentos mais eficientes nas duas situações foram glyphosate + diclosulam, glyphosate + 2,4-D e 2,4-D. A associação de glyphosate aos tratamentos incrementou o controle da rebrota independentemente da época de aplicação. / Reported cases of glyphosate resistant hairy fleabane have increased its im-portance in Brazilian agricultural. To understand the key principles to effective man-agement, the objectives of this research were to: (i) analyze hairy fleabane growth and development patterns in two different agricultural environments during peak emergence, (ii) evaluate the effects of stover and soil moisture on seedling emer-gence, (iii) obtain dose-response curves for alternative herbicides in a Conyza bonariensis glyphosate-resistant biotype and (iv) evaluate chemical control options for this biotype after cutting and regrowth. For these objectives, experiments in the field and greenhouse were conducted in Santa Cruz das Palmeiras, Sao Paulo State (SCP) and Nao-Me-Toque, Rio Grande do Sul State (NMT), during May, 2010 to May, 2012. At SCP, the germination and emergence of hairy fleabane occurred cycli-cally, peaking more in late summer and early spring and influenced by increased rainfall. In addition, the presence of little crop residue or stover in the ground seemed to exert more influence than temperature. At NMT, emergence was more concen-trated during the winter, when precipitation is not a limiting factor. Germination and emergence were favored by lower temperatures. For both sites, plants that germinat-ed in the coldest season of the year (July) showed slower initial development, with a more intensive biomass accumulation and peaked around 90-104 days after planting. Plants that germinated in the spring (September) also showed slower initial develop-ment, but their growth was more evenly distributed over time, and peaked about 80-90 days after planting. In greenhouse conditions, soil water content was more im-portant for influencing seedling emergence of hairy fleabane than the amount of stover and the highest emergence was observed in moist soil. In the presence of moisture, lower amounts of stover increased seedling emergence of hairy fleabane compared to bare soil. The presence of large quantities of stover on the soil surface resulted in emergence suppression. Glyphosate resistance in Conyza bonariensis, biotype B2, was confirmed by dose-response curves with susceptible biotype. The efficacy of alternative herbicides was different depending on the stage of the resistant biotype at application timing. The herbicides metsulfuron, diclosulam, 2,4-D, dicamba, atrazine, glufosinate and paraquat were the most effective in controlling the resistant biotype. In later stages the association with glyphosate resulted in a better control with metsulfuron, diclosulam and 2,4-D. More efficient control of hairy flea-bane regrowth (biotype B2) was observed when herbicides were applied on the same day that the plants were cut than when applied 7 days after cutting. The most effec-tive herbicide treatments in both situations were glyphosate + diclosulam, glyphosate + 2,4-D, and 2,4-D alone. The association of glyphosate in the herbicide treatments increased control of hairy fleabane regrowth regardless of application timing.

Casos reportados de buva com resistência ao glyphosate têm aumentado, ano após ano, a importância dessa planta daninha no cenário agrícola brasileiro. Com o intuito de entender alguns aspectos de sua biologia que resultem em manejo mais adequado, os objetivos deste trabalho foram: (i) identificar os períodos do ano em que ocorrem os maiores fluxos de emergência da buva e analisar seu crescimento e desenvolvimento em dois ambientes agrícolas distintos; (ii) avaliar os efeitos da cobertura vegetal e umidade em sua germinação e emergência; (iii) construir curvas de dose-resposta de um biótipo de Conyza bonariensis resistente ao glyphosate para herbicidas alternativos e (iv) avaliar as opções de manejo químico desse biótipo após o corte e rebrota. Para esses objetivos, experimentos foram conduzidos em campo e casa-de-vegetação nos municípios de Santa Cruz das Palmeiras, SP (SCP) e Não-Me-Toque, RS (NMT), entre maio de 2010 a maio de 2012. Em condições de campo, observou-se em SCP que a emergência da buva ocorre de forma escalonada, sendo mais concentrada no final do verão e início da primavera e a precipitação e a presença de pouca cobertura vegetal no solo parecem exercer mais influência que a temperatura. Em NMT, o fluxo de emergência é mais concentrado no inverno, em que a precipitação não é fator limitante, sendo a germinação e emergência favorecidas por temperaturas mais baixas. Nos dois locais, plantas que germinam na época mais fria do ano (julho) apresentam desenvolvimento inicial mais lento, com acúmulo de biomassa mais intenso e concentrado em torno dos 90-104 dias após a semeadura (DAS); plantas que germinam na primavera (setembro) também apresentam desenvolvimento inicial lento, porém seu crescimento é mais distribuído ao longo do tempo, com os picos de acúmulo aos 80-90 DAS. Em condições de casa-de-vegetação, a disponibilidade hídrica do solo foi mais importante para a emergência de plântulas de buva que a quantidade de cobertura vegetal (palha). Em solo úmido, menores quantidades de palha favorecem a emergência da buva em relação ao solo descoberto. Quantidades maiores de palha promovem supressão de sua emergência. A resistência ao glyphosate foi confirmada para o biótipo de C. bonariensis, coletado em SCP (biótipo B2) e a eficiência dos herbicidas alternativos foi diferente em função dos estádios de desenvolvimento desse biótipo no momento da aplicação. Os herbicidas metsulfuron, diclosulam, 2,4-D, dicamba, atrazine, glufosinate e paraquat foram os mais consistentes no controle do biótipo resistente, sendo que, no estádio mais avançado, a associação com glyphosate agregou no controle para metsulfuron, diclosulam e 2,4-D. Após o corte, controle mais eficiente da rebrota (biótipo B2) foi obtido quando a aplicação ocorreu no mesmo dia do corte que 7 dias depois e os tratamentos mais eficientes nas duas situações foram glyphosate + diclosulam, glyphosate + 2,4-D e 2,4-D. A associação de glyphosate aos tratamentos incrementou o controle da rebrota independentemente da época de aplicação. / Reported cases of glyphosate resistant hairy fleabane have increased its im-portance in Brazilian agricultural. To understand the key principles to effective man-agement, the objectives of this research were to: (i) analyze hairy fleabane growth and development patterns in two different agricultural environments during peak emergence, (ii) evaluate the effects of stover and soil moisture on seedling emer-gence, (iii) obtain dose-response curves for alternative herbicides in a Conyza bonariensis glyphosate-resistant biotype and (iv) evaluate chemical control options for this biotype after cutting and regrowth. For these objectives, experiments in the field and greenhouse were conducted in Santa Cruz das Palmeiras, Sao Paulo State (SCP) and Nao-Me-Toque, Rio Grande do Sul State (NMT), during May, 2010 to May, 2012. At SCP, the germination and emergence of hairy fleabane occurred cycli-cally, peaking more in late summer and early spring and influenced by increased rainfall. In addition, the presence of little crop residue or stover in the ground seemed to exert more influence than temperature. At NMT, emergence was more concen-trated during the winter, when precipitation is not a limiting factor. Germination and emergence were favored by lower temperatures. For both sites, plants that germinat-ed in the coldest season of the year (July) showed slower initial development, with a more intensive biomass accumulation and peaked around 90-104 days after planting. Plants that germinated in the spring (September) also showed slower initial develop-ment, but their growth was more evenly distributed over time, and peaked about 80-90 days after planting. In greenhouse conditions, soil water content was more im-portant for influencing seedling emergence of hairy fleabane than the amount of stover and the highest emergence was observed in moist soil. In the presence of moisture, lower amounts of stover increased seedling emergence of hairy fleabane compared to bare soil. The presence of large quantities of stover on the soil surface resulted in emergence suppression. Glyphosate resistance in Conyza bonariensis, biotype B2, was confirmed by dose-response curves with susceptible biotype. The efficacy of alternative herbicides was different depending on the stage of the resistant biotype at application timing. The herbicides metsulfuron, diclosulam, 2,4-D, dicamba, atrazine, glufosinate and paraquat were the most effective in controlling the resistant biotype. In later stages the association with glyphosate resulted in a better control with metsulfuron, diclosulam and 2,4-D. More efficient control of hairy flea-bane regrowth (biotype B2) was observed when herbicides were applied on the same day that the plants were cut than when applied 7 days after cutting. The most effec-tive herbicide treatments in both situations were glyphosate + diclosulam, glyphosate + 2,4-D, and 2,4-D alone. The association of glyphosate in the herbicide treatments increased control of hairy fleabane regrowth regardless of application timing.

A superfície da terra foi modificada nos últimos 50 anos mais do que em qualquer outro período da História, mais intensa e rápida nos trópicos pela expansão das frentes de ocupação humana sobre floresta madura. A Amazônia brasileira, caracterizada pela alternância de ciclos econômicos extrativistas, exemplifica esse processo. Entre o abandono de áreas degradadas e a abertura de novas frentes de ocupação, ocorre a regeneração florestal. A floresta secundária tem uma reconhecida importância para o restabelecimento das funções dos ecossistemas e dos estoques de nutrientes perdidos da floresta madura, mas ignorados por muitos anos de taxas oficiais de desmatamento na Amazônia brasileira. Este estudo apresenta uma abordagem utilizando Análise de Imagens Baseada em Objetos Geográficos (GEOBIA) para classificar os estágios de sucessão secundária numa área com cerca de 11.124 km² na região de Santarém (Pará, Brasil). Dentre os resultados, foram produzidas 19 diferentes classificações cobrindo o período 1984 a 2016, que permitiu identificar a redução da floresta madura e da floresta secundária devido à expansão da fronteira agrícola. Outro resultado relevante foi a modelagem de uma árvore de decisão aplicável às imagens de refletância de superfície coletadas pelos satélites LANDSAT, processando esses atributos de classificação em um aplicativo de mineração de dados / The earth surface was modified in the last 50 years more than in any other period of the History, more intense and fast in the tropics by the expansion of human occupation frontiers on the mature forest. The Brazilian Amazon, characterized by alternating extractive economic cycles, exemplifies this process. Between the degraded areas abandonment and the new occupation fronts, forest regeneration takes place. The secondary forest has a recognized importance for the restoration of ecosystem functions and the nutrient stocks lost from the mature forest but ignored for many years of official deforestation rates in the Brazilian Amazon. In this study, an approach using Geographic Object-Based Imaging Analysis (GEOBIA) is presented to classify the stages of secondary succession in an area with near 11,124 km² on Santarém region (Pará State, Brazil). Among the results, 19 different classifications were produced covering the period 1984 to 2016, which allowed identify the reduction of mature forest and secondary forest due to agricultural frontier expansion. Another relevant result was the modeling of a decision tree applicable to surface reflectance images collected by the LANDSAT satellites, processing these classifications attributes in a data mining software

Ma thèse porte sur l’étude par simulations numériques à l’échelle atomique de l’adsorption de molécules uniques et d’auto-assemblages moléculaires sur la surface de silicium Si(111) dopée bore notée Si(111) (√(3 ) x√3)R30°-B. Après un premier chapitre de présentation des méthodes de calcul, puis un chapitre consacré à la surface Si(111)-B, la thèse se divise en deux grandes parties : l’une concernant l’adsorption de molécules uniques et l’autre consacrée à l’adsorption de tapis moléculaire.La première partie concerne l’adsorption de molécules uniques sur la surface de Si(111) (√(3 ) x√3)R30°-B. Nous avons plus particulièrement étudié trois molécules présentant des mécanismes d’adsorption différents : la molécule de pyridile-azobenzène, une molécule de la famille des porphyrines (Cu-TBPP) et deux molécules appartenant à la famille des phtalocyanines (H2Pc et CuPc). Dans chaque étude, nous avons effectué une étude énergétique, structurale et électronique. Dans la plupart des cas, nous avons complété l’étude par un calcul d’image STM pour comparer avec les résultats expérimentaux. A partir de cette étude, nous avons montré que les molécules interagissent différemment avec la surface via des interactions électrostatiques, des liaisons datives, des liaisons ioniques et un mécanisme de cycloaddition. La deuxième partie de la thèse est dédiée à l’étude de l’auto-assemblage de molécules organiques sur la surface Si(111) (√(3 ) x√3)R30°-B. L’auto-assemblage moléculaire est une technique permettant la fabrication d’architectures hautement organisées à l’échelle atomique. Nous avons étudié trois molécules différentes formant un auto-assemblage sur la surface de Si(111)-B : 1,3,5-tri(4-bromophényle benzène) notée TBB, 1,3,5-tri(4-iodophényle benzène) notée TIB et 1,3,5-triphenylbenzene notée THB. Comme la formation d’un réseau auto-organisé est la conséquence d’un équilibre entre les interactions molécule-molécule et molécules-substrat, nous avons évalué les énergies d’interaction mises en jeu en utilisant différentes approximations (LDA, GGA et GGA+D). Nous avons étudié, ensuite, les propriétés électroniques de ces assemblages par le calcul des densités d’états projetées, de la différence de la densité de charge, du Laplacien de la charge ou de la fonction ELF. Afin de comparer nos résultats avec les résultats expérimentaux, nous avons effectué un calcul d’image STM en utilisant deux approches : l’approche de Tersoff-Hamann et l’approche multidiffusion proposée par le code bSKAN. Dans une dernière étape, nous avons étudié la recroissance de molécules de fullerène C60 sur le réseau auto-organisé de molécules de TBB déposées sur la surface Si(111) (√(3 ) x√3)R30° -B. Nous avons effectué une étude énergétique des molécules de C60 qui se déposent préférentiellement dans les nanopores de forme hexagonale en accord avec les expériences STM. / My thesis presents the study of the adsorption of single molecules and molecular self-assembly, by numerical simulations at the atomic scale, on a boron doped silicon surface denoted Si(111)(√(3 ) x√3)R30°-B. After presenting the calculation methods and describing the surface model, this thesis is made of two parts: the first one is about the adsorption of single molecules and the second one is devoted to the formation of supramolecular network. In the first part, I studied the adsorption of single molecules on the silicon surface doped boron Si (111)(√(3 ) x√3)R30°-B. I have investigated the adsorption mechanisms of three different molecules: a molecule of pyridyl-azobenzene, a molecule of the family of porphyrin (Cu-TBBP) and two molecules which belong to the family of phtalocyanine (H2Pc and CuPc). For every molecule, I conducted energetic, structural and electronic studies. In most of the cases, I completed this work by calculating STM images in order to compare with experimental results. The second part of this thesis deals with the study of self assembly of organic molecules on the surface of Si(111)(√(3 ) x√3)R30°-B. Molecular self assembly is a technique which allows the formation of highly organized architectures at the atomic scale. I have studied three different molecules forming self assembly on the surface of Si (111)(√(3 ) x√3)R30°-B : 1,3,5-tri(4-bromophenyl benzene) denoted TBB, 1,3,5-tri(4-iodophenyle benzene) denoted TIB et 1,3,5-triphenylbenzene denoted THB. As the formation of a self organized network is a result of equilibrium between molecule-molecule interaction and molecule-substrate one, I have evaluated the interaction energies by using different approximations (LDA, GGA and GGA+D). Then, I have studied the electronic properties of these assemblies by calculating the projected density of states, the charge difference and the Laplacien of the charge or the ELF function (Electronic Localization Function). In order to compare our results with experimental ones, STM images calculations were performed by using two different approaches: the approach of Tersoff-Hamann and the multi-scattering approach proposed by bSKAN code. Finally, I have studied the growth of C60 molecules on the self organized network formed by the TBB molecules deposited on the Si (111)(√(3 ) x√3)R30°-B surface. The energetic study shows that C60 molecules are adsorbed preferentially in the hexagonal nanopores in agreement with the STM observations.

Leafy vegetables, lettuce (Lactuca sativa L. cv. Green Oakleaf), pak choi (Brassica sinensis L. cv. Oriental Taisai) and rocket (Eruca sativa L.), were planted in an open field at Lincoln University on January 2005. Plants were harvested at 5 cm cutting height above the growing point with three different harvest start times, early start (ES), mid start (MS) and late start (LS) of harvest respectively. There were three harvests during the growing season with a 4-week interval between harvests. Generally, lettuce produced significantly higher total FW/plant (208 g) than pak choi or rocket (123 and 102 g total FW/plant, respectively). Lettuce also produced significantly higher total FW/plant than pak choi or rocket in each treatment. Lettuce produced significantly more total saleable leaf FW/plant in the ES, MS and LS treatment (137.5, 120.9 and 169.3 g FW/plant), compared with pak choi (52.9, 100 and 92 g FW/plant) or rocket (31.5, 92.2 and 56.4 g FW/plant). Pak choi produced higher total saleable leaf FW/plant than rocket in the ES and LS treatments, but a similar total saleable leaf FW/plant in the MS treatment. The best time to start harvesting was the LS treatment for lettuce, while pak choi and rocket produced better yields in the MS and LS treatments. Results for total DW/plant showed that different harvest start times did not affect the total DW/plant in lettuce. However, pak choi and rocket produced less total DW/plant in the ES treatment compared to the MS or LS treatments. This was due to a faster recovery by lettuce. In addition, lettuce produced significantly higher DW/plant during regrowth at the second and third harvests than pak choi or rocket, even though it was significantly lower at the first harvest. It is likely that after harvesting greater carbohydrate reserves and greater remaining leaf area produced greater regrowth potential in lettuce. These results suggest that lettuce has the most regrowth potential, while rocket has more than pak choi in this reaping and regrowth system. When plants were harvested at the same cutting level, lettuce had the most remaining leaf area of the three species. This remaining leaf area for lettuce could be another reason for faster recovery and more regrowth potential. More reserves and remaining leaf area may also be the reason for more regrowth potential in rocket compared to pak choi. Another important reason for the better performance of lettuce was that temperatures during the growing season were in the range of optimum temperatures (12-21 ºС), except for the regrowth between the second and third harvests in the LS. This relates to higher photosynthetic rates and in turn leads to faster recovery and regrwoth. Lettuce was the most suitable crop in the reaping and regrowth system in this experiment. However, rocket might also be appropriate for this system, particularly if the price is high enough to make it economically viable.

The conversion of native forests to pastures and crops is one of the most extensive causes of deforestation worldwide. Concomitant with agricultural landscape modification are the processes of habitat loss and fragmentation, which are major causes of species’ extinctions, population declines and altered ecosystem functions. However, in many tropical, sub-tropical and temperate regions, abandoned agricultural lands are reverting to regrowth or secondary forest, which represents an important opportunity for passive landscape restoration. Regrowth may be particularly important in highly modified landscapes, where the area of mature forest may be insufficient to support viable plant and animal communities without some form of restoration. Some studies of fauna populations in regrowth forest have found recovery of species richness within several decades, although recovery of species composition may take at least 100 years and some species may be permanently lost. While these findings are encouraging, they generally fail to account for the landscape context in which regrowth occurs and focus mainly on tropical forests. The aim of this thesis was to advance the understanding of fauna recovery in regrowth forests on abandoned agricultural land by: i) comparing woodland bird communities in a replicated chronosequence of semi-arid sub-tropical regrowth forests; and ii) quantifying how the ecological values of regrowth habitat vary among stand-, patch- and landscape-levels of ecological organisation. A review of 68 studies of fauna recovery in regrowth forests, revealed that current knowledge is limited by the predominance of studies conducted: in tropical rainforests; with minimal replication of sites; in landscapes within proximity of large tracts of relatively undisturbed mature forests; and with limited consideration of the influence of the spatial context on fauna recovery in regrowth forest. This study makes a significant contribution to understanding fauna recovery in regrowth forests by quantifying the recovery of estimated bird species richness to levels similar to mature forest, within a period of 30-60 years, in highly modified semi-arid agricultural landscapes in sub-tropical Australia. An ordination of the similarity in species composition among forest types also suggested that after 30-60 years regrowth bird communities are more similar to mature brigalow forest than the younger regrowth. This is important for the recovery of brigalow ecosystems, an endangered ecological community where regrowth is currently given minimal protection from further clearing. Comparisons of the importance of habitat attributes using model averaging and hierarchical partitioning of generalised linear models of the species richness of woodland birds showed that bird species richness was positively associated with patch age, and that stand-level factors such as grazing disturbance and the abundance of mistletoes (Amyema spp.) were also important. The spatial context of vegetation patches (size, shape and isolation) was equally important for bird species richness, with more species of woodland dependent, nectar/frugivores and non-ground foraging insectivores occurring in less modified landscape contexts, and the converse for generalist species, ground foraging insectivores and granivores. While a number of woodland dependent bird species known to be in decline in temperate woodlands of southern Australia were absent or rare in regrowth forests, several species (e.g., eastern yellow robin) also occupied regrowth habitats. This finding suggests that these more sensitive species may respond positively to landscape restoration through targeted retention of brigalow regrowth. The landscape-level amount of forest varied in importance among regrowth age classes and bird groups. In general, the amount and number of mature forest patches in the landscape were of lower importance than local attributes. However, the amount of mature forest and old regrowth (> 30 years) in the landscape did have an important positive influence on the number of woodland bird species and species’ abundance; suggesting that regrowth is making an important contribution to landscape recovery in the study area. Mistletoe abundance was strongly dependent on particular species of frugivores for seed dispersal (e.g., mistletoebird, spiny-cheeked honeyeater and painted honeyeater), and varied considerably among three sub-regions of the study area. In general, mistletoe abundance increased in linear patches and more highly modified landscapes but was also dependent on the abundance of seed dispersers and brigalow stand condition. These findings suggest that narrow linear patches in brigalow landscapes can have important conservation values for woodland birds. The study outcomes have important implications for research and management of regrowth vegetation, both within Australia and internationally. From an international perspective, the study highlights the need for greater consideration of the importance of regrowth forest in a landscape context for conserving and restoring fauna communities. From an Australian perspective, the study provides important baseline information for the conservation and management of woodland bird habitat in fragmented brigalow landscapes. Prior to this research, very little was known on the spatial ecology of woodland birds in the region. The study highlights the important conservation values of small and often linear mature brigalow patches for woodland birds and the considerable potential for restoration of habitat for a diverse range of species through the retention of regrowth vegetation. In particular, the research outcomes suggest that targeting the retention of regrowth towards increasing the size and reducing the isolation of mature brigalow forests may be an effective strategy to maximise biodiversity benefits. Brigalow regrowth stands will need to be retained for at least 60 years and probably longer to maintain viable woodland bird communities. For this to happen on a regional-scale, brigalow regrowth needs to be given greater recognition for potential biodiversity benefits either within a legislative framework or by incentive schemes to promote the long term persistence of regrowth habitat within the landscape.

The conversion of native forests to pastures and crops is one of the most extensive causes of deforestation worldwide. Concomitant with agricultural landscape modification are the processes of habitat loss and fragmentation, which are major causes of species’ extinctions, population declines and altered ecosystem functions. However, in many tropical, sub-tropical and temperate regions, abandoned agricultural lands are reverting to regrowth or secondary forest, which represents an important opportunity for passive landscape restoration. Regrowth may be particularly important in highly modified landscapes, where the area of mature forest may be insufficient to support viable plant and animal communities without some form of restoration. Some studies of fauna populations in regrowth forest have found recovery of species richness within several decades, although recovery of species composition may take at least 100 years and some species may be permanently lost. While these findings are encouraging, they generally fail to account for the landscape context in which regrowth occurs and focus mainly on tropical forests. The aim of this thesis was to advance the understanding of fauna recovery in regrowth forests on abandoned agricultural land by: i) comparing woodland bird communities in a replicated chronosequence of semi-arid sub-tropical regrowth forests; and ii) quantifying how the ecological values of regrowth habitat vary among stand-, patch- and landscape-levels of ecological organisation. A review of 68 studies of fauna recovery in regrowth forests, revealed that current knowledge is limited by the predominance of studies conducted: in tropical rainforests; with minimal replication of sites; in landscapes within proximity of large tracts of relatively undisturbed mature forests; and with limited consideration of the influence of the spatial context on fauna recovery in regrowth forest. This study makes a significant contribution to understanding fauna recovery in regrowth forests by quantifying the recovery of estimated bird species richness to levels similar to mature forest, within a period of 30-60 years, in highly modified semi-arid agricultural landscapes in sub-tropical Australia. An ordination of the similarity in species composition among forest types also suggested that after 30-60 years regrowth bird communities are more similar to mature brigalow forest than the younger regrowth. This is important for the recovery of brigalow ecosystems, an endangered ecological community where regrowth is currently given minimal protection from further clearing. Comparisons of the importance of habitat attributes using model averaging and hierarchical partitioning of generalised linear models of the species richness of woodland birds showed that bird species richness was positively associated with patch age, and that stand-level factors such as grazing disturbance and the abundance of mistletoes (Amyema spp.) were also important. The spatial context of vegetation patches (size, shape and isolation) was equally important for bird species richness, with more species of woodland dependent, nectar/frugivores and non-ground foraging insectivores occurring in less modified landscape contexts, and the converse for generalist species, ground foraging insectivores and granivores. While a number of woodland dependent bird species known to be in decline in temperate woodlands of southern Australia were absent or rare in regrowth forests, several species (e.g., eastern yellow robin) also occupied regrowth habitats. This finding suggests that these more sensitive species may respond positively to landscape restoration through targeted retention of brigalow regrowth. The landscape-level amount of forest varied in importance among regrowth age classes and bird groups. In general, the amount and number of mature forest patches in the landscape were of lower importance than local attributes. However, the amount of mature forest and old regrowth (> 30 years) in the landscape did have an important positive influence on the number of woodland bird species and species’ abundance; suggesting that regrowth is making an important contribution to landscape recovery in the study area. Mistletoe abundance was strongly dependent on particular species of frugivores for seed dispersal (e.g., mistletoebird, spiny-cheeked honeyeater and painted honeyeater), and varied considerably among three sub-regions of the study area. In general, mistletoe abundance increased in linear patches and more highly modified landscapes but was also dependent on the abundance of seed dispersers and brigalow stand condition. These findings suggest that narrow linear patches in brigalow landscapes can have important conservation values for woodland birds. The study outcomes have important implications for research and management of regrowth vegetation, both within Australia and internationally. From an international perspective, the study highlights the need for greater consideration of the importance of regrowth forest in a landscape context for conserving and restoring fauna communities. From an Australian perspective, the study provides important baseline information for the conservation and management of woodland bird habitat in fragmented brigalow landscapes. Prior to this research, very little was known on the spatial ecology of woodland birds in the region. The study highlights the important conservation values of small and often linear mature brigalow patches for woodland birds and the considerable potential for restoration of habitat for a diverse range of species through the retention of regrowth vegetation. In particular, the research outcomes suggest that targeting the retention of regrowth towards increasing the size and reducing the isolation of mature brigalow forests may be an effective strategy to maximise biodiversity benefits. Brigalow regrowth stands will need to be retained for at least 60 years and probably longer to maintain viable woodland bird communities. For this to happen on a regional-scale, brigalow regrowth needs to be given greater recognition for potential biodiversity benefits either within a legislative framework or by incentive schemes to promote the long term persistence of regrowth habitat within the landscape.

The conversion of native forests to pastures and crops is one of the most extensive causes of deforestation worldwide. Concomitant with agricultural landscape modification are the processes of habitat loss and fragmentation, which are major causes of species’ extinctions, population declines and altered ecosystem functions. However, in many tropical, sub-tropical and temperate regions, abandoned agricultural lands are reverting to regrowth or secondary forest, which represents an important opportunity for passive landscape restoration. Regrowth may be particularly important in highly modified landscapes, where the area of mature forest may be insufficient to support viable plant and animal communities without some form of restoration. Some studies of fauna populations in regrowth forest have found recovery of species richness within several decades, although recovery of species composition may take at least 100 years and some species may be permanently lost. While these findings are encouraging, they generally fail to account for the landscape context in which regrowth occurs and focus mainly on tropical forests. The aim of this thesis was to advance the understanding of fauna recovery in regrowth forests on abandoned agricultural land by: i) comparing woodland bird communities in a replicated chronosequence of semi-arid sub-tropical regrowth forests; and ii) quantifying how the ecological values of regrowth habitat vary among stand-, patch- and landscape-levels of ecological organisation. A review of 68 studies of fauna recovery in regrowth forests, revealed that current knowledge is limited by the predominance of studies conducted: in tropical rainforests; with minimal replication of sites; in landscapes within proximity of large tracts of relatively undisturbed mature forests; and with limited consideration of the influence of the spatial context on fauna recovery in regrowth forest. This study makes a significant contribution to understanding fauna recovery in regrowth forests by quantifying the recovery of estimated bird species richness to levels similar to mature forest, within a period of 30-60 years, in highly modified semi-arid agricultural landscapes in sub-tropical Australia. An ordination of the similarity in species composition among forest types also suggested that after 30-60 years regrowth bird communities are more similar to mature brigalow forest than the younger regrowth. This is important for the recovery of brigalow ecosystems, an endangered ecological community where regrowth is currently given minimal protection from further clearing. Comparisons of the importance of habitat attributes using model averaging and hierarchical partitioning of generalised linear models of the species richness of woodland birds showed that bird species richness was positively associated with patch age, and that stand-level factors such as grazing disturbance and the abundance of mistletoes (Amyema spp.) were also important. The spatial context of vegetation patches (size, shape and isolation) was equally important for bird species richness, with more species of woodland dependent, nectar/frugivores and non-ground foraging insectivores occurring in less modified landscape contexts, and the converse for generalist species, ground foraging insectivores and granivores. While a number of woodland dependent bird species known to be in decline in temperate woodlands of southern Australia were absent or rare in regrowth forests, several species (e.g., eastern yellow robin) also occupied regrowth habitats. This finding suggests that these more sensitive species may respond positively to landscape restoration through targeted retention of brigalow regrowth. The landscape-level amount of forest varied in importance among regrowth age classes and bird groups. In general, the amount and number of mature forest patches in the landscape were of lower importance than local attributes. However, the amount of mature forest and old regrowth (> 30 years) in the landscape did have an important positive influence on the number of woodland bird species and species’ abundance; suggesting that regrowth is making an important contribution to landscape recovery in the study area. Mistletoe abundance was strongly dependent on particular species of frugivores for seed dispersal (e.g., mistletoebird, spiny-cheeked honeyeater and painted honeyeater), and varied considerably among three sub-regions of the study area. In general, mistletoe abundance increased in linear patches and more highly modified landscapes but was also dependent on the abundance of seed dispersers and brigalow stand condition. These findings suggest that narrow linear patches in brigalow landscapes can have important conservation values for woodland birds. The study outcomes have important implications for research and management of regrowth vegetation, both within Australia and internationally. From an international perspective, the study highlights the need for greater consideration of the importance of regrowth forest in a landscape context for conserving and restoring fauna communities. From an Australian perspective, the study provides important baseline information for the conservation and management of woodland bird habitat in fragmented brigalow landscapes. Prior to this research, very little was known on the spatial ecology of woodland birds in the region. The study highlights the important conservation values of small and often linear mature brigalow patches for woodland birds and the considerable potential for restoration of habitat for a diverse range of species through the retention of regrowth vegetation. In particular, the research outcomes suggest that targeting the retention of regrowth towards increasing the size and reducing the isolation of mature brigalow forests may be an effective strategy to maximise biodiversity benefits. Brigalow regrowth stands will need to be retained for at least 60 years and probably longer to maintain viable woodland bird communities. For this to happen on a regional-scale, brigalow regrowth needs to be given greater recognition for potential biodiversity benefits either within a legislative framework or by incentive schemes to promote the long term persistence of regrowth habitat within the landscape.

The conversion of native forests to pastures and crops is one of the most extensive causes of deforestation worldwide. Concomitant with agricultural landscape modification are the processes of habitat loss and fragmentation, which are major causes of species’ extinctions, population declines and altered ecosystem functions. However, in many tropical, sub-tropical and temperate regions, abandoned agricultural lands are reverting to regrowth or secondary forest, which represents an important opportunity for passive landscape restoration. Regrowth may be particularly important in highly modified landscapes, where the area of mature forest may be insufficient to support viable plant and animal communities without some form of restoration. Some studies of fauna populations in regrowth forest have found recovery of species richness within several decades, although recovery of species composition may take at least 100 years and some species may be permanently lost. While these findings are encouraging, they generally fail to account for the landscape context in which regrowth occurs and focus mainly on tropical forests. The aim of this thesis was to advance the understanding of fauna recovery in regrowth forests on abandoned agricultural land by: i) comparing woodland bird communities in a replicated chronosequence of semi-arid sub-tropical regrowth forests; and ii) quantifying how the ecological values of regrowth habitat vary among stand-, patch- and landscape-levels of ecological organisation. A review of 68 studies of fauna recovery in regrowth forests, revealed that current knowledge is limited by the predominance of studies conducted: in tropical rainforests; with minimal replication of sites; in landscapes within proximity of large tracts of relatively undisturbed mature forests; and with limited consideration of the influence of the spatial context on fauna recovery in regrowth forest. This study makes a significant contribution to understanding fauna recovery in regrowth forests by quantifying the recovery of estimated bird species richness to levels similar to mature forest, within a period of 30-60 years, in highly modified semi-arid agricultural landscapes in sub-tropical Australia. An ordination of the similarity in species composition among forest types also suggested that after 30-60 years regrowth bird communities are more similar to mature brigalow forest than the younger regrowth. This is important for the recovery of brigalow ecosystems, an endangered ecological community where regrowth is currently given minimal protection from further clearing. Comparisons of the importance of habitat attributes using model averaging and hierarchical partitioning of generalised linear models of the species richness of woodland birds showed that bird species richness was positively associated with patch age, and that stand-level factors such as grazing disturbance and the abundance of mistletoes (Amyema spp.) were also important. The spatial context of vegetation patches (size, shape and isolation) was equally important for bird species richness, with more species of woodland dependent, nectar/frugivores and non-ground foraging insectivores occurring in less modified landscape contexts, and the converse for generalist species, ground foraging insectivores and granivores. While a number of woodland dependent bird species known to be in decline in temperate woodlands of southern Australia were absent or rare in regrowth forests, several species (e.g., eastern yellow robin) also occupied regrowth habitats. This finding suggests that these more sensitive species may respond positively to landscape restoration through targeted retention of brigalow regrowth. The landscape-level amount of forest varied in importance among regrowth age classes and bird groups. In general, the amount and number of mature forest patches in the landscape were of lower importance than local attributes. However, the amount of mature forest and old regrowth (> 30 years) in the landscape did have an important positive influence on the number of woodland bird species and species’ abundance; suggesting that regrowth is making an important contribution to landscape recovery in the study area. Mistletoe abundance was strongly dependent on particular species of frugivores for seed dispersal (e.g., mistletoebird, spiny-cheeked honeyeater and painted honeyeater), and varied considerably among three sub-regions of the study area. In general, mistletoe abundance increased in linear patches and more highly modified landscapes but was also dependent on the abundance of seed dispersers and brigalow stand condition. These findings suggest that narrow linear patches in brigalow landscapes can have important conservation values for woodland birds. The study outcomes have important implications for research and management of regrowth vegetation, both within Australia and internationally. From an international perspective, the study highlights the need for greater consideration of the importance of regrowth forest in a landscape context for conserving and restoring fauna communities. From an Australian perspective, the study provides important baseline information for the conservation and management of woodland bird habitat in fragmented brigalow landscapes. Prior to this research, very little was known on the spatial ecology of woodland birds in the region. The study highlights the important conservation values of small and often linear mature brigalow patches for woodland birds and the considerable potential for restoration of habitat for a diverse range of species through the retention of regrowth vegetation. In particular, the research outcomes suggest that targeting the retention of regrowth towards increasing the size and reducing the isolation of mature brigalow forests may be an effective strategy to maximise biodiversity benefits. Brigalow regrowth stands will need to be retained for at least 60 years and probably longer to maintain viable woodland bird communities. For this to happen on a regional-scale, brigalow regrowth needs to be given greater recognition for potential biodiversity benefits either within a legislative framework or by incentive schemes to promote the long term persistence of regrowth habitat within the landscape.

Many researchers have highlighted the dire prospects for biodiversity in fragmented agricultural landscapes and stressed the need for increasing the area of, and connectivity between, natural ecosystems. Some have advocated the use of naturally regenerating forest ecosystems for sequestering atmospheric carbon, with opportunities for dual restoration and carbon benefits. However, no studies have explicitly explored the feasibility of obtaining such dual benefits from a regenerating woody ecosystem. This thesis aims to provide a detailed assessment of the restoration and carbon potential of Brigalow regrowth, an extensive naturally regenerating ecosystem throughout the pastoral regions of north eastern Australia. It combines observational, experimental and modelling techniques to describe the agricultural legacy of pastoral development, identify constraints to restoration and explore methods to remove these constraints. A review of existing ecological knowledge of Brigalow ecosystems is provided in chapter 3, along with discussion of policy and socio-economic issues that are likely to influence how and to what extent regrowth is utilised for restoration and carbon purposes in the Brigalow Belt. The review found restoring regrowth is likely to have benefits for a wide range of native flora and fauna, including the endangered bridled nailtail wallaby. Knowledge gaps exist relating to the landscape ecology of Brigalow regrowth and the impacts of management and climate change on carbon and restoration potential. Also, a conflict exists between short-term carbon sequestration and long-term restoration goals. Regional demand for high biomass regrowth as a carbon offset is likely to be high but ambiguities in carbon policy threaten to diminish the use of natural regrowth for reforestation projects. A large cross-sectional study of regrowth is presented in chapter 4. Data were analysed using multi-level / hierarchical Bayesian models (HBMs). Firstly, we found that repeated attempts at clearing Brigalow regrowth increases stem densities and densities remain high over the long term, particularly in high rainfall areas and on clay soils with deep gilgais. Secondly, higher density stands have slower biomass accumulation and structural development in the long term. Spatial extrapolations of the HBMs indicated that the central and eastern parts of the study region are most environmentally suitability for biomass accumulation, however these may not correspond to the areas that historically supported the highest biomass Brigalow forests. We conclude that carbon and restoration goals are largely congruent within regions of similar climate. At the regional scale however, spatial prioritisation of restoration and carbon projects may only be aligned in areas with higher carbon potential. Given the importance of stem density in determining restoration and carbon potential, an experimental thinning trial was established in dense Brigalow regrowth in southern Queensland (chapter 5). Four treatments were applied in a randomised block design and growth and mortality of a subset of stems was monitored for two years. Data were analysed using mixed-effects models and HBMs and the latter were subsequently used to parameterise an individual-based simulation model of stand structural development and biomass accumulation over 50 years. The main findings of this study were that growth and mortality of stems is influenced by the amount of space available to each stem (a neighbourhood effect) and that thinning accelerates structural development and increases woody species diversity. The examination of neighbourhood effects is taken further by considering drought-related mortality in a Eucalyptus savanna ecosystem (chapter 6). For this work a multi-faceted approach was employed including spatial pattern analyses and statistical models of stem survival to test three competing hypotheses relating to neighbourhood effects on drought related tree mortality. The main finding of this study was that neighbour density and microsite effects both influence drought-related mortality and the observed patterns can readily be explained by an interaction between these two factors. As a whole, this thesis contributes the following scientific insights: (1) restoration and carbon goals may be aligned for naturally regenerating woody ecosystems, but the degree of goal congruence will vary across the landscape in question, (2) while some woody ecosystems retain an excellent capacity to regenerate naturally, the agricultural legacy may still have long term effects on restoration and carbon potential, (3) neighbourhood effects that operate at the stem scale strongly influence dynamics at the ecosystem scale.