Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Pterocarpus angolensis is one of the timber tree species that regenerates naturally in the dry forest of Namibia, mainly assisted by the influence of forest fires. Tree development goes through a prolonged suffrutex stage to reach the sapling stage and then, finally, the bole tree stage. This study focused on assessing the main factors facilitating the development of Pterocarpus angolensis seedlings through the suffrutex stage to the sapling stage in Namibia dry forests. To achieve the study objectives three study locations (Okongo and Ncumcara Community Forests and Caprivi State Forest) were selected, representing a rainfall gradient. Within each study location, two different fire history treatments (recently burnt (RB) and recently unburnt (RU)) were selected, and four plots were randomly selected from each fire history treatment. Face to face individual interviews was conducted with community members surrounding the three forests to obtain indigenous knowledge information about Pterocarpus angolensis tree development. Seedlings and saplings found in all plots were counted and measured (tree height and diameter at breast height (DBH)) while trees more than 3 m high were only counted and measured for DBH. Laboratory analysis was performed to determine basic soil texture and nutrient status. In addition, destructive sampling was done on individual trees in the seedling and sapling stages at each study location. The destructive samples allowed for estimation of biomass in above and below ground components, determination of carbohydrate storage in the taproots and estimation of tree age by counting growth rings on the neck disc of the taproot sample. These measures could shed light on the tree development through the suffrutex stage. The main agents causing Pterocarpus angolensis tree damage and stand disturbances observed are drought, fires, insects, diseases, temperature, lightning, wind, animals and humans. Forest fires were found to be one of the major disturbances in all the study locations, particularly damaging to seedlings when fire intensity is high. Likewise, the most important factors influencing the tree development from seedlings to sapling and sapling to bole tree stages are soil water, soil fertility, plant competition, sunlight and fires. Through counting growth rings of taproot neck discs, it is estimated that the ages of seedlings most commonly range from 5 to 12 years in the dry forests of Okongo, Ncumcara and Caprivi. The soil texture in the three forests is dominated by sand, with the soil reaction usually being moderately acidic while the soils have low levels of organic carbon, phosphorus and exchangeable base cations. This study revealed that Caprivi State Forest (location with the highest rainfall) has the highest stand density followed by Okongo Community Forest and Ncumcara Community Forest with the lowest. Trees were grouped into different DBH and height classes. The highest numbers of trees are found in DBH class 0 – 10 cm and in height class 0.6 – 1.0 m at Okongo Community Forest but at Ncumcara and Caprivi many of the trees are in height class 1.1 – 1.5 m. The mean DBH difference is significant between locations but not significant between fire history treatments. A higher abundance of mature trees are found at Okongo Community Forest while a greater abundance of saplings occur at Ncumcara Community Forest which shows a significant difference between study locations. Seedling abundance is the same across study locations and fire history treatments. The difference in stand structure between study locations appears to be strongly influenced by different management regimes on the three locations. A majority of respondents from all the study locations alleged soil water followed by soil fertility as the main influential factors to Pterocarpus angolensis development. Again, most of the respondents revealed that seedling takes 4 – 7 years to reach sapling stage and their main environmental disturbance is fire. Tree cutting by members of the community was also perceived by the respondents as an important non-environmental disturbance. The most abundant tree development stage perceived by respondents was mature trees while seedlings rated the sparsest stage. Based on the respondents no silvicultural practices are performed to promote Pterocarpus angolensis growth. It follows that the Kiaat trees are currently growing without human intervention that might enhance their development. A combination of social survey (interview) and ecological survey provided reliable information on ecological processes. A weak positive significant correlation relationship existed between shoot mass (aboveground biomass) and taproot mass (belowground biomass), meaning when the taproot mass increases the shoot mass also increases. Analysis of non-structural carbohydrates (NSC) storage in taproots showed that both sugar and starch contents in the taproots could facilitate the survival of the tree during suffrutex stages and its rapid growth thereafter. Based on this study Pterocarpus angolensis regeneration in these three dry forests is poor because seedling abundance is the lowest compared to saplings and mature trees. These study findings can be used as the basis for further studies to predict Pterocarpus angolensis natural regeneration in the dry forests, as well as input when management regimes are being developed for the dry forests of North Namibia. / AFRIKAANSE OPSOMMING: Pterocarpus angolensis (Kiaat) is een van die boomspesies wat natuurlik verjong in die droë bosveld van Namibië, met die hulp van bosbrande. Die boom ontwikkel deur ʼn lang semi-struik stadium waartydens die boompies as saailinge bekendstaan. Daarna ontwikkel dit deur die jongboom stadium tot dit uiteindelik die kroon stadium bereik. Hierdie studie fokus op die faktore bydra tot die ontwikkeling van Pterocarpus angolensis van die semi-struik stadium na die jongboom stadium in die droë bosveld van Namibië. Om die doelstellings van die tesis te bereik is drie studiegebiede gekies langs ʼn reënvalgradiënt (naamlik Okongo en Ncumcara gemeenskapsbosse asook Caprivi Staatsbos). Binne elke studiegebied is twee behandelings met verskillende brandgeskiedenis gekies (gebrand of nie-gebrand in die onlangse verlede). Vier persele is ewekansig uit elk van hierdie behandelings gekies vir eksperimentering. Persoonlike onderhoude is gevoer met gemeenskapslede wat in die omgewing woon ten einde inheemse kennis en inligting te versamel oor die ontwikkeling van die jong Pterocarpus angolensis bome. Alle saailinge en jongbome wat voorkom in die persele is getel en gemeet (boomhoogte en deursnee op borshoogte (DBH)) terwyl bome wat hoër as 3 m is, slegs getel en vir DBH gemeet is. Laboratoriumtoetse is gedoen op grondmonsters ten einde ‘n basiese beskrywing van die grondtekstuur en voedingstofstatus te verkry. Verder is destruktiewe bemonstering toegepas op bome in beide die saailing en jongboom stadium op elke studiegebied. Hierdie bemonstering het dit moontlik gemaak om bogrondse en ondergrondse biomassa te skat, om die opberging van koolhidrate in die penwortels te bepaal, en ook om die boom ouderdom te skat vanaf jaarringe in die nek van die penwortel monster. Hierdie metings kon lig werp op die boomontwikkeling deur die semi-struik stadium. Die faktore wat skade aan Pterocarpus angolensis bome veroorsaak asook versteuring van die opstande waarin die bome voorkom is droogte, brande, insekte, siektes, temperatuur uiterstes, weerlig, wind, diere en mense. Die bevindinge dui op bosbrande as een van die belangrikste versteuringsfaktor in al drie studiegebiede; dit is veral skadelik vir saailinge in die semi-struik stadium wanneer die vuurintensiteit hoog is. Die faktore wat die boomontwikkeling van saailing, na jongboom en kroonstadium beïnvloed is hoofsaaklik grondwater, grondvrugbaarheid, plantkompetisie, sonlig en brande. Die ouderdom van saailinge (bepaal vanaf jaarring tellings in die nek van penwortel monsters) van die meeste saailinge én jongbome is na raming tussen 5 en 12 jaar vir die droë bosse in die studiegebiede van Okongo, Ncumcara en Caprivi. Die grondtekstuur van hierdie studie se drie bosgebiede is hoofsaaklik sanderig, met ’n effens suur grondreaksie terwyl die gronde lae vlakke van organiese koolstof, fosfor, en uitruilbare basiese katione bevat. Die studie het aangedui dat Caprivi staatsbos (met die hoogste reënval) die digste opstande huisves, gevolg deur Okongo en dan Ncumcara gemeenskapsbos, met die laagste digtheid. Bome is gegroepeer in verskillende DBH en hoogte klasse. Die meeste bome kom voor in die DBH klas van 0-10 cm en in die hoogteklas van 0.6 – 1.0 m by Okongo, maar by Ncumcara en Caprivi is daar meer bome in die hoogteklas van 1.1 - 1.5 m. Die gemiddelde DBH verskil is betekenisvol tussen studiegebiede, maar is nie betekenisvol verskillend tussen brandgeskiedenis behandelings nie. ’n Hoër voorkoms van volwasse bome is by Okongo aangetref, terwyl ’n hoër voorkoms van jongbome by Ncumcara waargeneem is, en hierdie verskil was statisties betekenisvol. Die voorkoms van saailinge is soortgelyk oor alle studiegebiede en brandgeskiedenis behandelings heen. Die verskil in die struktuur van die opstande op die drie studiegebiede word skynbaar sterk beïnvloed deur verskillende bestuurspraktyke wat in elke gebied toegepas word. Die meerderheid van respondente van al drie studiegebiede beweer dat grondwater, gevolg deur grondvrugbaarheid die belangrikste faktore is wat P. angolensis ontwikkeling beïnvloed. Meeste van die respondente onthul dat saailinge 4 tot 7 jaar neem om die jongboom stadium te bereik en dat die belangrikste versteuringsagent bosbrande is. ʼn Belangrike nie-omgewingsfaktor wat verantwoordelik is vir versteuring in die bosse is mense wat bome, lote en/of takke afsaag. Respondente is van mening dat volwasse bome die grootteklas met die mees algemene voorkoms is, terwyl saailinge die skaarsste grootteklas uitmaak. Die respondente het aangedui dat geen boskultuurpraktyke toegepas word om die groei van P. angolensis aan te help nie. Die gevolgtrekking is dus dat die Kiaatbome tans groei sonder menslike ingryping om hul ontwikkeling te verbeter. Die kombinasie van persoonlike onderhoude en ʼn ekologiese opnames het betroubare inligting rakende ekologiese prosesse opgelewer. ’n Swak positiewe, maar betekenisvolle korrelasie bestaan tussen die massa van die bogrondse lote en die penwortelmassa, wat beteken dat die lote se massa toeneem met toenemende wortelmassa. Analise van opgebergde nie-strukturele koolhidraatreserwes in die penwortel toon dat beide suiker- én styselinhoud in die penwortels die oorlewing van die boom in die struikstadium aanhelp, asook sy vinnige groei na die struikstadium. Die feit dat die saailinge minder volop is as jongbome en volwasse bome in hierdie studie dui aan dat verjonging van Pterocarpus angolensis in hierdie droë bosse maar swak is. Die bevindinge van die studie bevat inligting wat gebruik kans word (a) as die grondslag van verdere studies op die natuurlike verjonging van Pterocarpus angolensis in droë bosse, en (b) as inset wanneer bestuursaanbevelings vir die droë bosse van Noord Namibië ontwikkel word.

CAPES / A comunidade da fauna edáfica tropical é diversa, porém com escassas informações taxonômicas em projetos de restauração. Esses organismos são indicativos da qualidade ambiental, sendo o seu monitoramento essencial para uma análise ecossistêmica. O objetivo do presente trabalho foi avaliar o papel da fauna edáfica como bioindicadora da qualidade ambiental em áreas sob diferentes tecnologias de restauração florestal. O trabalho foi conduzido na estação experimental da Universidade Tecnológica Federal do Paraná, Dois Vizinhos, Paraná. Os tratamentos avaliados foram: Restauração Passiva (RP; regeneração natural); Nucleação (NC; conjunto de técnicas recobrindo 1/3 da área); e Plantio de Alta Diversidade (PAD; plantio de árvores em área total). Adjacente ao experimento, a floresta secundária em estágio médio de regeneração (FL), serviu como área referência. O delineamento experimental foi em blocos ao acaso, com quatro repetições e três subamostras por parcela. As famílias de Coleoptera foram coletadas através de armadilhas Pitfall (04/2011) e a mesofauna e colêmbolos, foram extraídos em funis de Berlese-Tüllgren (12/2015). Foram amostrados 866 besouros em 16 famílias, sendo os herbívoros mais abundantes nos tratamentos de restauração e os não herbívoros na floresta. A RP e a FL foram os tratamentos mais diversos. Na Análise de Similaridade (ANOSIM), houve diferenças entre as tecnologias de restauração e a FL e, entre RP e PAD, sendo essas informações corroboradas pela Análise de Componentes Principais (ACP). Para a mesofauna, foram coletados 15.367 indivíduos e a riqueza e abundância de organismos foi superior na FL e a RP apresentou a comunidade mais uniforme. A ANOSIM apenas não diferenciou a interação entre RP e PAD, os demais tratamentos avaliados apresentam uma comunidade edáfica diferenciada entre si. Os grupos Hemiptera, Haplotaxida, Trichoptera, Acariformes, Diplopoda e Pseudoscorpiones foram os principais responsáveis pela distinção das tecnologias através da análise de porcentagem de similaridade (SIMPER). Na ACP, a floresta se separou das tecnologias, ficando associada aos Acariformes, Diplopoda, Diplura, Hemiptera e Pseudoscorpiones. Foram amostrados 2.429 Colêmbolos em 35 morfotipos, sendo a riqueza média superior na FL e a abundância superior na FL e PAD. O índice de diversidade de Shannon encontrados seguiu um gradiente de intervenção antrópica (FL>RP>NC>PAD). A ANOSIM encontrou dissimilaridades entre as três tecnologias de restauração e a floresta, que se separou das demais na ACP. A fauna edáfica foi um eficiente indicador da qualidade ambiental, diferenciando as tecnologias em processo inicial de restauração da floresta e já mostrando algumas particularidades entre as tecnologias em si. Para efetivar seu papel bioindicadores, o monitoramento deve ser realizado a longo prazo, identificando os grupos chave em áreas em áreas em processo de restauração florestal. / The community of tropical edaphic fauna is diverse, but with scarce taxonomic information on restoration projects. These organisms are indicative of environmental quality, and their monitoring is essential for an ecosystem analysis. The objective of this work was to evaluate the role of soil fauna as a bioindicator of environmental quality in areas under different forest restoration technologies. The work was conducted at the experimental station of the Universidade Tecnológica Federal do Paraná, Dois Vizinhos, Paraná. The treatments evaluated were: Passive Restoration (RP, natural regeneration); Nucleation (NC, set of techniques covering 1/3 of the area); And High Diversity Planting (PAD, planting of trees in total area). Adjacent to the experiment, the secondary forest in the middle stage of regeneration (FL) served as a reference area. The experimental design was in randomized blocks, with four replications and three sub - samples per plot. Coleoptera families were collected through Pitfall traps (04/2011) and the mesofauna and Collembola were extracted in Berlese-Tüllgren funnels (12/2015). A total of 866 beetles were sampled in 16 families, with herbivores being most abundant in restoration treatments and non - herbivores in the forest. RP and FL were the most diverse treatments. In the Analysis of Similarity (ANOSIM), there were differences between the restoration technologies and the FL and, between RP and PAD, being this information corroborated by the Principal Component Analysis (PCA). For the mesofauna, 15,367 individuals were collected and the richness and abundance of organisms was higher in FL and RP presented the most uniform community. ANOSIM only did not differentiate the interaction between RP and PAD, the other evaluated treatments present a differentiated edaphic community among them. The groups Hemiptera, Haplotaxida, Trichoptera, Acariformes, Diplopoda and Pseudoscorpiones were the main responsible for the differentiation of the technologies through the similarity percentage analysis (SIMPER). In the ACP, the forest separated from the technologies, being associated with the Acariformes, Diplopoda, Diplura, Hemiptera and Pseudoscorpiones. 2,429 Collembola were sampled in 35 morphotypes, with the upper average richness in FL and the superior abundance in FL and PAD. The diversity index of Shannon found followed a gradient of anthropic intervention (FL> RP> NC> PAD). ANOSIM found dissimilarities between the three restoration technologies and the forest, which separated from the others in the ACP. The edaphic fauna was an efficient indicator of the environmental quality, differentiating the technologies in the initial process of forest restoration and already showing some peculiarities among the technologies themselves. In order to realize its role bioindicators, the monitoring should be carried out in the long term, identifying the key groups in areas in areas in the process of forest restoration.

CAPES / A comunidade da fauna edáfica tropical é diversa, porém com escassas informações taxonômicas em projetos de restauração. Esses organismos são indicativos da qualidade ambiental, sendo o seu monitoramento essencial para uma análise ecossistêmica. O objetivo do presente trabalho foi avaliar o papel da fauna edáfica como bioindicadora da qualidade ambiental em áreas sob diferentes tecnologias de restauração florestal. O trabalho foi conduzido na estação experimental da Universidade Tecnológica Federal do Paraná, Dois Vizinhos, Paraná. Os tratamentos avaliados foram: Restauração Passiva (RP; regeneração natural); Nucleação (NC; conjunto de técnicas recobrindo 1/3 da área); e Plantio de Alta Diversidade (PAD; plantio de árvores em área total). Adjacente ao experimento, a floresta secundária em estágio médio de regeneração (FL), serviu como área referência. O delineamento experimental foi em blocos ao acaso, com quatro repetições e três subamostras por parcela. As famílias de Coleoptera foram coletadas através de armadilhas Pitfall (04/2011) e a mesofauna e colêmbolos, foram extraídos em funis de Berlese-Tüllgren (12/2015). Foram amostrados 866 besouros em 16 famílias, sendo os herbívoros mais abundantes nos tratamentos de restauração e os não herbívoros na floresta. A RP e a FL foram os tratamentos mais diversos. Na Análise de Similaridade (ANOSIM), houve diferenças entre as tecnologias de restauração e a FL e, entre RP e PAD, sendo essas informações corroboradas pela Análise de Componentes Principais (ACP). Para a mesofauna, foram coletados 15.367 indivíduos e a riqueza e abundância de organismos foi superior na FL e a RP apresentou a comunidade mais uniforme. A ANOSIM apenas não diferenciou a interação entre RP e PAD, os demais tratamentos avaliados apresentam uma comunidade edáfica diferenciada entre si. Os grupos Hemiptera, Haplotaxida, Trichoptera, Acariformes, Diplopoda e Pseudoscorpiones foram os principais responsáveis pela distinção das tecnologias através da análise de porcentagem de similaridade (SIMPER). Na ACP, a floresta se separou das tecnologias, ficando associada aos Acariformes, Diplopoda, Diplura, Hemiptera e Pseudoscorpiones. Foram amostrados 2.429 Colêmbolos em 35 morfotipos, sendo a riqueza média superior na FL e a abundância superior na FL e PAD. O índice de diversidade de Shannon encontrados seguiu um gradiente de intervenção antrópica (FL>RP>NC>PAD). A ANOSIM encontrou dissimilaridades entre as três tecnologias de restauração e a floresta, que se separou das demais na ACP. A fauna edáfica foi um eficiente indicador da qualidade ambiental, diferenciando as tecnologias em processo inicial de restauração da floresta e já mostrando algumas particularidades entre as tecnologias em si. Para efetivar seu papel bioindicadores, o monitoramento deve ser realizado a longo prazo, identificando os grupos chave em áreas em áreas em processo de restauração florestal. / The community of tropical edaphic fauna is diverse, but with scarce taxonomic information on restoration projects. These organisms are indicative of environmental quality, and their monitoring is essential for an ecosystem analysis. The objective of this work was to evaluate the role of soil fauna as a bioindicator of environmental quality in areas under different forest restoration technologies. The work was conducted at the experimental station of the Universidade Tecnológica Federal do Paraná, Dois Vizinhos, Paraná. The treatments evaluated were: Passive Restoration (RP, natural regeneration); Nucleation (NC, set of techniques covering 1/3 of the area); And High Diversity Planting (PAD, planting of trees in total area). Adjacent to the experiment, the secondary forest in the middle stage of regeneration (FL) served as a reference area. The experimental design was in randomized blocks, with four replications and three sub - samples per plot. Coleoptera families were collected through Pitfall traps (04/2011) and the mesofauna and Collembola were extracted in Berlese-Tüllgren funnels (12/2015). A total of 866 beetles were sampled in 16 families, with herbivores being most abundant in restoration treatments and non - herbivores in the forest. RP and FL were the most diverse treatments. In the Analysis of Similarity (ANOSIM), there were differences between the restoration technologies and the FL and, between RP and PAD, being this information corroborated by the Principal Component Analysis (PCA). For the mesofauna, 15,367 individuals were collected and the richness and abundance of organisms was higher in FL and RP presented the most uniform community. ANOSIM only did not differentiate the interaction between RP and PAD, the other evaluated treatments present a differentiated edaphic community among them. The groups Hemiptera, Haplotaxida, Trichoptera, Acariformes, Diplopoda and Pseudoscorpiones were the main responsible for the differentiation of the technologies through the similarity percentage analysis (SIMPER). In the ACP, the forest separated from the technologies, being associated with the Acariformes, Diplopoda, Diplura, Hemiptera and Pseudoscorpiones. 2,429 Collembola were sampled in 35 morphotypes, with the upper average richness in FL and the superior abundance in FL and PAD. The diversity index of Shannon found followed a gradient of anthropic intervention (FL> RP> NC> PAD). ANOSIM found dissimilarities between the three restoration technologies and the forest, which separated from the others in the ACP. The edaphic fauna was an efficient indicator of the environmental quality, differentiating the technologies in the initial process of forest restoration and already showing some peculiarities among the technologies themselves. In order to realize its role bioindicators, the monitoring should be carried out in the long term, identifying the key groups in areas in areas in the process of forest restoration.

No description available.

Six forest areas destroyed by fire representing different seral stages of aspen development and conifer invasion were studied to determine successional dynamics and the related livestock and big game use. Factors measured were: (a) age, basal area, density and frequency of aspen and conifer trees; (b) density and frequency of under-story species; (c) forage production for forbs, grasses, and browse, and (d) animal-days use for deer, cattle and sheep. Aspen appeared in the community the spring following the fire and conifers appeared fifteen to twenty years later. Conifers had begun to dominate aspen on an eighty-two year old stand. The density and frequency of understory species was influenced by grazing pressure, age of the cormnunity and conifer basal area. Maximum densities were reached twenty years after the fire. Forage production was influenced by the age of the community and conifer basal area. Maximum forage production was reached on the twenty-one year old burn. Animal use was influenced by the amount of forage production, conifer basal area and competitive use by other animals.

Canopy mortality. species abundance. and the species composition and origin of regeneration in mixed oak forests were studied following a 1900 ha man-caused early growing season wildfire in Shenandoah National Park. in the Blue Ridge Physiographic Province. Virginia. Pre-fire stands were dominated by chestnut. scarlet, and northern red oaks growing on medium quality sites (50 year upland oak site index 16-20 m). Permanent vegetation plots were established in four stands for each of high and low levels of fire intensity. and unburned stands. High-intensity fire killed 67% of the basal area and 81% of the trees, whereas low-intensity fire resulted in mortality of 8% of the basal area and 15% of the trees. The mean height of stem-bark char accounted for 91% and 95% of the variation in percent of the basal area and number of trees killed by fire, respectively. Logistic regression models were developed to predict the probability of fire-induced individual tree mortality (top-kill) as a function of DBH and height of stem-bark char for chestnut oak, scarlet and northern red oaks, pignut hickory, blackgum. and red maple. Blackgum and chestnut oak were the most fire resistant species studied. High-intensity fire resulted in the development of a new stand, whereas low-intensity fire resulted in thinning of the overstory and understory. Most species present in pre-fire stand reproduced via basal sprouts, chestnut oak sprouts were the most abundant stems taller than 1 m two growing seasons after high-intensity fire. Tree-of-heaven was the only species to regenerate by seed and able to match the height growth of oak basal sprouts. This research suggests that oaks are capable of replacing themselves on medium quality sites following wildfire-induced canopy removal in 55 to 60 year old stands. / Master of Science

Catastrophic wind events can play an important role in the stand structure and composition in Bottomland Hardwood Forests. Regeneration and stand structure following these events depends on a variety of factors, including disturbance severity, past land use, and post-disturbance management. This study revisits a 2004 survey conducted at Mermet Lake State Fish and Wildlife Area in Southern Illinois following a tornado and subsequent salvage logging operation. We established 164 plots on four different disturbance types as mapped by the original survey: Undisturbed, Transition, Wind Damaged Only, and Wind Damaged Salvaged. The objective of this study was to see how recovery differed among these. Data collected included density, basal area, and Shannon’s H, as well as visual evidence of remaining soil rutting resulting from the salvage logging operation, tree height as a metric for productivity, and invasive percent cover. There were slight but significant differences in the densities, basal area, and diversity among disturbance types, although diameter distributions revealed similar age distributions and there was no impact of the salvage logging on productivity. Evidence of soil rutting was still present, adding to microsite diversity that contributed to the significantly higher species diversity of Wind Damaged Salvaged areas. The proportion of Quercus spp. in both Wind Damaged Only and Wind Damaged Salvaged areas was lower than in Undisturbed and Transition areas, while the proportion of other species, including Fraxinus pennsylvanica and key bottomland taxa Salix spp., Taxodium distichum, and Nyssa aquatica, were higher. Invasive non-native species cover was higher in Wind Damaged Salvaged and Wind Damaged Only areas than in Transition and Undisturbed but was confined to forest edges and did not differ between Wind Damaged Salvaged and Wind Damaged Only areas. The results indicate that twenty years after the disturbance, forest structure is still recovering in tornado-damaged areas and has shifted in composition away from Quercus toward domination by Acer spp., Ulmus spp., Fraxinus pennsylvanica, and Liquidambar styraciflua species in both Wind Damaged Only and Wind Damaged Salvaged areas. The salvage logging operation did not have any negative impacts on forest recovery and supported biodiversity by further diversifying overstory community composition to include key wetland species that support the conservation area’s bottomland restoration efforts. Active management should be considered in both Wind Damaged Only and Wind Damaged Salvaged areas to prevent the spread of non-native species and ensure the persistence of Quercus and other key bottomland species in support of conservation objectives.

Este trabalho teve como objetivo investigar a recuperação da fauna durante a sucessão florestal, através de duas abordagens distintas. No primeiro capítulo, visando a identificação das lacunas e oportunidades para o avanço do tema, realizamos uma revisão de artigos sobre sucessão em comunidades animais em florestas neotropicais analisados criticamente quanto: (1) às regiões e grupos estudados, (2) à qualidade dos trabalhos com relação a adequação do delineamento amostral, (3) aos padrões observados (diversidade, biomassa e estrutura), e (4) à base teórica utilizada. Foram encontrados e analisados 33 trabalhos, os quais focaram em poucos grupos da fauna, principalmente aves, mamíferos e formigas. No geral, a maioria dos trabalhos é descritiva, não explicitando expectativas sobre os padrões e mecanismos responsáveis pela recuperação da fauna, não apresenta delineamento amostral adequado, principalmente no que se refere à justificativa da alocação dos sítios de amostragem com relação a fatores de confusão, e quantifica de maneira categórica, e muitas vezes imprecisa e arbitrária, a sucessão. As lacunas identificadas nesta revisão apontam a limitação do conhecimento atual sobre os padrões e mecanismos associados à sucessão em comunidades animais em florestas neotropicais, o que conseqüentemente implica na falta de informações que embasem a elaboração de planos de manejo e restauração destas florestas. Já o segundo capítulo refere-se à investigação empírica da recuperação da comunidade de pequenos mamíferos entre estádios sucessionais em uma área contínua de Mata Atlântica. Verificamos a congruência das modificações observadas na riqueza, composição e estrutura da comunidade estudada com as expectativas geradas pelos dois principais mecanismos propostos na literatura: (1) substituição de espécies causada por demandas conflitantes (trade-offs), associada ao gradiente de produtividade primária líquida e disponibilidade de recursos durante a sucessão, ou (2) aumento de diversidade causado pela possibilidade de partição de nicho, associado ao aumento da biomassa e da complexidade da vegetação, e da diversidade de recursos durante este processo. Embora a riqueza, estrutura e composição da comunidade não tenham sido influenciadas pela sucessão, houve uma mudança na abundância de parte das espécies da comunidade, com algumas aumentando e outras diminuindo das matas mais jovens para as mais tardias. Nossos resultados indicam que a hipótese de demandas conflitantes é mais plausível para explicar a recuperação da fauna de pequenos mamíferos durante a sucessão florestal / This study aims at investigating fauna recovery during forest succession using two distinct approaches. In the first chapter, in order to identify the gaps and opportunities for advancing our understanding of this subject, we carried out a review of articles on succession in animal communities in neotropical forests, which were critically analyzed in relation to: (1) the study regions and study groups, (2) the quality with respect to the adequacy of the sampling design, (3) the observed patterns (diversity, biomass and structure), and (4) the theoretical basis. We found and analyzed 33 studies, which focused on a few wildlife groups, especially birds, mammals, and ants. In general, most studies are descriptive, with no explicit expectations about the patterns and mechanisms responsible for wildlife recovery, lack adequate sampling design, especially concerning the justification for the allocation of sampling sites with respect to confounding factors, and quantify succession into categories, which are often imprecise and arbitrary. The gaps identified in this review indicate the limitation of our current knowledge on the patterns and mechanisms associated with succession in animal communities in neotropical forests, which consequently implies in the lack of information for developing management and restoration plans for these forests. The second chapter refers to an empirical investigation on the recovery of small mammal communities across successional stages in a continuous area of Atlantic Forest. We verified the congruence of the observed changes in community richness, composition and structure with the expectations generated by the two main mechanisms proposed in the literature: (1) species replacement caused by trade-offs, associated with the gradient in net primary productivity and resource availability during succession, or (2) increase in diversity caused by the possibility of niche partitioning, associated with increased vegetation biomass and complexity, and increased resource diversity during this process. Although community richness, structure and composition were not influenced by succession, there was a change in the abundance of some species, with some increasing and others decreasing from younger to older forests. Our results indicate that the hypothesis on trade-offs is more plausible to explain the recovery of small mammal communities during forest succession

Maritime forests are a critical interface between ocean and terrestrial ecosystems, providing important ecosystem services and functions. Along the U.S. southern Atlantic coast, maritime forests are dominated by <i>Quercus virginiana</i>. Maritime forests and <i>Q. virginiana</i> have been heavily impacted by conversion to agriculture, residential development, and pine stands. Southern pine beetle outbreaks have led to salvage and thinning silvicultural treatments of pine stands which offer an opportunity to restore more complex maritime forests. This research project is comprised of two experiments which allowed me to study the performance of planted <i>Q. virginiana</i> seedlings in response to (1) animal browse, (2) competing vegetation, and (3) varying overstory pine canopies. For both experiments, one-year-old bareroot seedlings were planted as split-plot experimental designs. The first experiment evaluated control of deer browse (fenced and not fenced whole plots) and competing vegetation (0, 1, and 2-yr vegetation control subplots) as independent variables. Overall seedling survival was 60% after two years. There was a significant interaction between deer browse and competing vegetation for seedling height, diameter, crown width, and lateral branches. Seedlings were larger for all response parameters when fenced with vegetation control. Vegetation control significantly improved seedling performance only in fenced plots, indicating a shift in pressure from herbivory to competition when deer were excluded. Foliar nitrogen (N) was significantly greater in fenced plots than non-fenced plots and in 2-yr vegetation control subplots than non-weeded subplots. The second experiment evaluated varying pine overstories (clearcut, heavy thin, light thin, and no thin whole plots) and competing vegetation control (0 and 2-yr vegetation control subplots). Overall seedling survival was 78% after one growing season, with clearcut plots at the greatest survival (83%) and no thin at the lowest (72%). Seedling growth and foliar nitrogen were significantly greater in clearcut plots followed by the heavy thin, light thin, and no thin plots. Vegetation control consistently promoted seedling height, but was only beneficial to diameter and crown width in clearcut/heavy thin plots. <i>Q. virginiana</i> seedlings demonstrated plasticity in their ability to acclimate to the varying microclimates created by silvicultural treatments, as demonstrated by light response curves, stomatal density, and specific leaf area. These results highlight the importance of fencing to remove deer browse, introducing light in the understory, and further improving seedling performance by removing competing vegetation.

L’installation de plantules est une phase critique fortement influencée par les interactions avec la végétation établie, compétition ou facilitation. Dans cette thèse, nous montrons que l’effet du pin d’Alep ou d'arbustes sur l’installation d’espèces feuillues dépend de la densité du couvert, de la stratégie des espèces cibles et nurses et des conditions locales. Sous couverts très denses, la survie et la croissance des plantules sont drastiquement limitées par compétition lumineuse et hydrique, le stress hydrique étant renforcé par une faible allocation de biomasse aux racines. À l’autre extrémité du gradient, en milieu ouvert, la photoinhibition et la concurrence avec les herbacées peuvent limiter l'installation des plantules. Les espèces sclérophylles sempervirentes sont peu sensibles aux fortes irradiances, températures et demandes évaporatives et peuvent profiter de conditions favorables momentanées par polycyclisme en milieu ouvert. L’effet d’un couvert végétal sur ces espèces est principalement compétitif, tandis que les espèces décidues à fort SLA bénéficient d’un couvert modéré. En pépinière, la litière des principales espèces ligneuses modifie les propriétés physico-chimiques et microbiologiques du sol sous-jacent mais sans effet sur des plantules de chêne au bout de 2 ans, montrant un faible effet allélopathique. L’éclaircie des peuplements de pin d’Alep denses est une stratégie pour faciliter l’installation d’espèces feuillues et ainsi améliorer la diversité et la résilience au feu des forêts. L’optimum de couvert semble se déplacer vers des couverts plus denses dans des sites à conditions climatiques ou édaphiques plus sévères et pour les espèces décidues. / Seedling establishment is a critical demographic phase, strongly influenced by plant-plant interactions. This thesis shows that the effect of Aleppo pine and shrubs on broadleaved seedling establishment depends on vegetation cover density, target and nurse species strategies and local conditions. A dense vegetation cover strongly limits seedling establishment by light and water competition, seedlings water stress being worsened by a low biomass allocation to roots. At the other extreme, in the open, photoinhibition and competition with grasses can limit seedling establishment. Sclerophyllous species are poorly sensitive to high temperature, irradiance and evaporative demand and can take advantage of favorable conditions at any time of the year by polycyclism in the open: interactions with pine are thus mostly competitive. In contrast, deciduous species with high SLA are more sensitive to photo-inhibition and benefit from the protection of a moderate cover, under which they are able to grow faster. In a nursery experiment, pine and shrub litters modified soil chemical and microbiological properties but without feedback on oak seedlings, indicating a poor allelopathic effect. Pine thinning is a strategy to enhance broadleaved seedling establishment and increase Mediterranean forest diversity and fire-resilience. However, the optimum thinning intensity seems to decrease in harsher climatic or edaphic conditions and for deciduous species.