Artificial brightness of the night sky caused by the backscatter of artificial light in the atmosphere is a consequence of ongoing urbanization. Skyglow covers 88 % of Europe’s surface and poses significant threats to biodiversity. Extensive research on responses of bats to direct light pollution already revealed significant impacts. However, evidence for the influence of skyglow is scarce. Therefore, this study investigates the effects of skyglow on bat activity patterns, namely Pipistrellus pygmaeus and Myotis species, in a rural area outside of Stockholm, Sweden. Additionally, the analysis includes the role of local habitat structures and landscape composition at multiple scales for both activity rate and timing of emergence.The two focal species showed diverging behaviour in their main habitat on the local scale. While Myotis spp. emergence was delayed by about half an hour above the water surface, P. pygmaeus appeared about 20 minutes earlier in forest edges under brighter night skies. Landscape-level skyglow significantly delays the emergence of Myotis spp. above water surfaces by 18 minutes, but P. pygmaeus did not respond to skyglow at the landscape-level. Both, Myotis species and P. pygmaeus, appeared earlier in forest edges than above water surfaces. Evidence on skyglow affecting bat activity rates was weak. Here, local habitat and landscape structure were more important for both species. The total length of all forest edges decreased bat activity at most scales, while activity was lower with the proportion of water and open land at different scales. In conclusion, bat conservation programmes need to consider the effect of skyglow as well as landscape characteristics.

Stream crossings are an integral component of forest road systems that provide access for timber harvesting and silvicultural activities. Stream crossings and their associated approaches are often the most critical point of concern for water quality along forest roads. Several types of crossings are used for extracting timber, but limited studies actually compare different types of stream crossings with regard to their effect on water quality. The objectives of this study were to examine four different stream crossing structures: 1) steel bridges, 2) pole bridges (pipe with poles), 3) standard culverts, and 4) re-enforced fords (with GeoWeb or Geotextile) to determine the influence of stream crossing type on water quality and to evaluate erosion associated with stream crossing approaches. We also evaluated each site at four different time intervals to determine if water quality was more affected during different stages of the operations. Prior to operational timber harvests, we identified six replications for each type of crossings (4 fords) and collected data at four time intervals: 1) prior to reopening or installation of crossing, 2) after crossing installation, 3) during harvest operation, and 4) after road closure. Potential erosion rates from approaches to the crossings were estimated by collecting the road/site information necessary to estimate erosion with the Water Erosion Prediction Project for forest roads (WEPP) and the forest version of the Universal Soil Loss Equation (USLE). In-stream water samples were collected at fixed locations above and below each crossing and were evaluated for total dissolved solids (TDS), pH, conductivity, water temperature, and total suspended solids (TSS) or sediment concentration. Steel bridge crossings generally caused the least amount of water quality disturbance. Model-generated estimates of erosion demonstrated that culvert crossings were associated with the highest average soil loss potential. Although steel bridge crossings had the best overall results, pole bridges proved to be a viable option for ephemeral or intermittent streams due to low potential of soil loss. Ford crossings were found to impact water quality indicators, but showed a decrease in total dissolved solids (TDS) after installation, prior to harvest. Overall, the steel skidder bridges were generally the best crossing type, but any of the crossings can be used effectively with minimal impact under specific site conditions and with judicious installation, use, and closure. Road/skid trail location and adherence to existing road grade, water control, cover, and closure best management practices are critical for protection of water quality at stream crossings. / Master of Science

Tropical forests are under continual threat due to deforestation and forest fragmentation processes which are driven by the economic activities growth, mainly agriculture. Replacing forest with other land uses can cause severe impacts on river water quality, altering its physical, chemical and biological characteristics. The Atlantic Forest, in particular, had its original vegetation cover reduced to about 11%, wherein the crop lands expansion and urban sprawl still threatening this important ecosystem and the ecosystem services that it provides. In this sense, the main objective of this study was to investigate the relation between forest cover and water quality of tropical agricultural watersheds. For that, six experimental watersheds with different percentage of forest cover were selected in the Sarapuí River watershed, State of São Paulo, Brazil. Water samples were collected during a hydrologic year to obtain water quality parameters that represent impacts induced by anthropic activities. According to the percentage of forest cover, the watersheds were denominated as \"forested\", when they presented more than 55% of forest cover, and \"degraded\", with less than 35%. Multivariate statistical models were applied to identify differences between these two groups. In a second moment, the relation of land use/land cover within the watershed and within its respective riparian zone, represented in this study by the Permanent Preservation Areas (PPA), with water quality was compared through mixed models and redundancy analysis to identify the main factors that influenced water quality variability. Lastly, a watershed simulation modeling was applied to verify the impact of riparian forest restoration on water quality of the Sarapuí River watershed, wherein each experimental watershed was represented by a sub-watershed in the model. The results showed that the degraded watersheds presented higher values of solids, turbidity, nutrients and coliforms, besides presenting greater temporal data variability compared to forested watersheds. This variation is associated with the stream flow changes during the year. In general, forest cover was related to good water quality, while agriculture and urban areas were responsible for the water quality degradation. Pasture presented mixed impacts, but it was not generally correlated with poor water quality. The water quality parameters responded differently to the influence of land-use/land-cover patterns in the watershed and riparian zone, but the overall water quality is better explained by the landscape composition within the watershed. Nevertheless, the watershed simulation indicated that PPA restoration reduces the sediment and nutrients loading into the river. Thus, it is possible to conclude that tropical forest plays a fundamental role in the water resources conservation, reducing impacts of human activities in watersheds and the watershed management with forest restoration strategies for the entire watershed is critical for the maintenance of water quality to water supply, despite the importance of the riparian zone. / As florestas tropicais estão sob constante ameaça devido ao processo de desmatamento e fragmentação florestal impulsionado pelo crescimento das atividades econômicas, em especial, a agricultura. A substituição de áreas florestadas por outros usos do solo pode causar impactos severos na qualidade da água de rios, alterando suas características físicas, químicas e biológicas. A Mata Atlântica, em especial, teve sua cobertura original reduzida a cerca de 11%, sendo que a expansão de terras cultiváveis e urbanização ainda ameaçam esse importante ecossistema e os serviços ecossistêmicos prestados por ele. Nesse sentido, este estudo propôs investigar a relação da cobertura florestal com a qualidade da água de microbacias agrícolas tropicais. Para tanto, foram selecionadas seis microbacias experimentais com diferentes porcentagens de cobertura florestal na bacia do rio Sarapuí, Estado de São Paulo, Brasil, onde foram feitas coletas de amostras de água por um ano hidrológico para a obtenção de parâmetros que representassem alterações na água induzidas por atividades antrópicas. Inicialmente as microbacias foram classificadas em \"florestadas\" e \"degradadas\", e modelos estatísticos multivariados foram aplicados para identificar diferenças entre os grupos. Em um segundo momento comparou-se a relação do uso e cobertura do solo na microbacia e na Área de Preservação Permanente (APP) com a qualidade da água utilizando-se modelos mistos e análise de redundância para identificar os principais fatores que influenciam a variabilidade da qualidade da água. Por último foi gerado um modelo hidrológico para simular o impacto da restauração da floresta ripária na qualidade da água da bacia do rio Sarapuí onde cada microbacia experimental desse estudo foi representada por uma sub-bacia do modelo. Os resultados mostram que as microbacias degradadas apresentam valores maiores de sólidos, turbidez, nutrientes e coliformes. Além disso, apresentam maior variabilidade temporal dos dados em relação às microbacias florestadas associada às alterações da vazão do rio. Em geral, a cobertura florestal foi relacionada à boa qualidade da água, enquanto que agricultura e ocupação urbana foram os usos do solo responsáveis pela degradação da qualidade da água. O uso pastagem apresentou impactos mistos, porém no geral não foi correlacionado à qualidade da água ruim. Os parâmetros de qualidade da água responderam de forma diferente quanto à influência dos padrões de uso e cobertura do solo na microbacia e na APP, porém, considerando-se todos parâmetros em conjunto, a qualidade da água é melhor explicada pela composição da paisagem da microbacia. Ainda assim, a simulação do modelo indicou que a restauração das APPs reduz a carga de sedimentos e nutrientes para o rio. Com isso, conclui-se que a floresta tropical tem papel fundamental na conservação dos recursos hídricos, reduzindo impactos das atividades humanas exercidas nas microbacias e que, apesar da importância das APPs na redução de poluentes para o rio, o manejo de bacias com estratégias de restauração florestal para toda a microbacia é extremamente importante para a manutenção da qualidade da água para abastecimento.

O objetivo deste trabalho foi comparar os cenários de inclusão e de não inclusão da delimitação da zona ripária da microbacia na determinação dos riscos ambientais, na adequação do uso do solo e conseqüentemente no planejamento sócio-ambiental, contribuindo com a elaboração e implementação dos planos de manejo integrado de microbacias com uso agrícola diversificado, considerando como premissas a busca da agricultura sustentável, a restauração do ecossistema ripário e o envolvimento social e econômico do produtor rural. Através de estudo de caso realizado na microbacia do Ribeirão São João (3.656 ha) no município de Mineiros do Tietê (SP), que faz parte do Programa Estadual de Microbacias Hidrográficas do Estado de São Paulo, foram feitas análises das suas condições sócio-ambientais que constaram de: a-) preparação de base cartográfica; b-) diagnóstico e planejamento participativos; c-) descrição de cenários convencionais e de cenários com inclusão da zona ripária para a adequação do uso do solo e caracterização dos riscos ambientais; d-) discussão sobre as relações entre o cenário que inclui a zona ripária e a legislação ambiental, a distribuição da estrutura fundiária, o uso e manejo agrícola e as estradas rurais e e-) proposta de um programa de monitoramento sócio-ambiental. O cenário com inclusão da zona ripária revelou que a microbacia possui 49,5 % de sua área com uso adequado, 20,4 % com sub utilização do solo e 1,9 % com sobre utilização. Quanto aos riscos de erosão, 60,2 % de sua área é considerada de baixo risco, 6,2 % possui moderado risco e 5,4 % compreende alto risco. Já o cenário convencional indicou que 59,0 % da área estão ocupados com uso adequado, 28,2 % com sub utilização, 2,6 % com sobre utilização, 76, 9 % da microbacia possui baixo risco de erosão, 11,0 % moderado e 12,1 % alto risco. Esta alteração induz o planejador a tomar medidas incompletas para a proteção das áreas que representam maiores riscos para a saúde da microbacia. Na microbacia estudada, 27,6 % da zona ripária está inserida em Área de Preservação Permanente, portanto protegida pelas leis ambientais, e 72,2 % estão sendo utilizados para agricultura, correndo risco de degradação. Em média, 26,1 % das áreas das propriedades rurais da microbacia se encontram em zona ripária. Parte destas poderia ser protegida pela Área de Preservação Permanente e pelo estabelecimento das reservas legais. A porção da zona ripária que não estiver protegida pela legislação ambiental deveria ter um manejo diferenciado de acordo com seu uso. Em vários pontos as estradas rurais atravessam os rios e a zona ripária podendo ocorrer danos ambientais se medidas corretas de adequação de estradas não forem tomadas. O cenário alternativo proposto corresponde também aos principais anseios da comunidade da microbacia, isto é, a preservação dos recursos hídricos, detectados através do diagnóstico e planejamento participativos. Levando em conta as condições da microbacia, assim como evidências baseadas na revisão de literatura, a proposta inclui o monitoramento sócio-ambiental, compreendendo o monitoramento da água, do solo, da integridade da paisagem, da biodiversidade agroambiental e dos aspectos socioeconômicos. / This work aims to compare the sceneries of including and not including the watershed riparian zone delimitation during the evaluation of the environmental risks in the land use planning, thus contributing for the implementation of integrated watershed management plans in the search of sustainable agriculture, based on the premises of riparian ecosystem restoration, as well as the direct participation of the land owners in the decision support process. A case study was developed in the São João creek Watershed, in the Municipality of Mineiros do Tiete, State of Sao Paulo. The case study included the preparation of the cartographic basis, diagnostic analysis and participative planning, description of conventional land use sceneries and alternative land use sceneries which include the delimitation of the watershed riparian zone, the comparison of the alternative sceneries in relation to the requirements of the Brazilian Forest Code in terms of stream buffer zone protection, as well as in relation to the watershed landownership structure , prevailing land use practices and rural roads design, and a proposition of an environmental monitoring program for the study watershed. The scenery that includes the riparian zone showed that 49,5% of the watershed total area has inadequate soil use, whereas 20,4% of the area with sub-utilization and 1,9% of the area with over-utilization. In terms of erosion risks, 60,2% of the watershed area can be considered with low erosion risk , 6,2% has moderate risk and 5,4% with high risk of soil erosion. The conventional scenery indicated that 59% of the watershed area has inadequate land use, 28,2% of the area is sub used, 2,6 % of the land is over used, 76,9% of the land has low risk of erosion, 11% has moderated soil erosion risk and 12,1% of the total area has high risk of soil erosion. Around 27,6% of the riparian zone are located in the Forest Code stream protection area, and 72,2 % of the area is prone to hydrological degradation due to inadequate land use practices. An average of 26,1% of the area of the watershed rural properties are located in the riparian zone. Part of this area should be protected according to the environmental law, or alternatively by the establishment of Legal Reserves. The portion of the riparian zone that is being used against the environmental law requirements should at least have a more conservative management approach. Rural roads cross the riparian zone in several locations and many of them cross the streams, which can pose hydrological risks. The proposed alternative scenery is in accordance with the main interests of the land owners, as detected in the participative planning, during which they raised concern about water resources conservation strategies. Considering the prevailing watershed conditions and also the information acquired in the literature survey, the study includes the monitoring of some water, soil, landscape integrity, biodiversity and socio-economic indicators.

Made available in DSpace on 2015-03-05T16:19:36Z (GMT). No. of bitstreams: 0 Previous issue date: 26 / Nenhuma / Este estudo foi realizado em dez fragmentos de floresta ripária localizados no sul do Brasil (30°09’S, 51°36’W; 46 m de altitude). Entre as dez florestas ripárias selecionadas, cinco estavam circundadas por pastejo de gado e as outras cinco estavam circundadas por plantações de eucalipto. Foi avaliada a sustentabilidade de Campomanesia rhombea, Diospyros inconstans, Myrciaria cuspidata e Sebastiania commersoniana através de análises da estrutura de tamanho, as quais foram realizadas em duas escalas. Em escala local, foram consideradas as populações presentes nos fragmentos circundados por pastejo de gado ou por plantações de eucalipto e, em escala regional considerou-se também áreas florestais maiores, tomadas como referência (Inventário Florestal Contínuo do Rio Grande do Sul). Em escala local, nas populações presentes em fragmentos circundados por plantações de eucalipto, prevaleceram indivíduos de pequenas classes de tamanho, e em áreas expostas ao pastejo de gado, as mesmas espécies apresentaram uma falha / This studied was carried in ten riparian forest fragments located southern Brazil. Of the ten riparian forests selected for study, five were embedded in pasturelands and five in eucalyptus plantations. We assessed the population sustentability of Campomanesia rhombea, Diospyros incontans, Myrciaria cuspidata and Sebastiania commersoniana through analyses of size structure, which were carried out at two scales. At a local scale, we consider populations in fragments surrounded by pastures or eucalyptus forest plantations, and at a regional scale we also consider larger forest tracts taken as reference areas (Rio Grande do Sul Forest Inventory databank). At local scale, the populations in fragments embedded by eucalyptus plantations prevailed small size classes individuals, and in areas exposed to cattle ranching, the same species seem to have a recurring failure of small individuals. Regional analyses included only established individuals with DBH > 1.6 cm. In this scale, populations in fragments surrounded by

Os processos hidrológicos afetam os processos biogeoquímicos, pois o movimento da água nos vários compartimentos do agroecossistema promove a redistribuição dos nutrientes, como o nitrogênio (N) e o carbono orgânico dissolvido (COD). O carreamento desse N e COD nos corpos hídricos se dão, normalmente, via escoamento superficial trazendo implicações negativas à sua qualidade. Em culturas anuais, como a cana-de-açúcar, há exigência de grande quantidade de fertilizantes inorgânicos e orgânicos que têm o N e o COD como os principais elementos. A floresta ripária desempenha funções relacionadas à geração do escoamento direto em microbacia e a retenção de nutrientes. Este trabalho tem como objetivo realizar o balanço hídrico e determinar o fluxo de N e COD em duas microbacias com cobertura de cana-de-açúcar, sendo que, uma microbacia apresenta floresta ripária próxima ao riacho em conformidade com a legislação vigente (Cana com floresta ripária - CCF) e a outra não apresenta floresta ripária nessas condições (Cana sem floresta ripária - CSF). Para tanto as microbacias foram instrumentalizadas para medir e coletar simultaneamente dados hidrológicos e amostras de chuva (entradas) e dos riachos (saídas) para análises de N e COD. As vertentes estudadas nas microbacias foram subdivididas em três porções: inferior, intermediária e superior, sendo que a primeira, na microbacia CCF encontra-se exclusivamente em floresta ripária. O monitoramento hidrológico ocorreu semanalmente no primeiro ano de estudo, e quinzenalmente no segundo. Já o monitoramento biogeoquímico das entradas e saídas ocorreu semanalmente. Para realizar o balanço de massa foram computadas as entradas via fertilizantes inorgânicos e orgânicos na cultura. A precipitação foi de 1200 mm no primeiro ano de estudo e 1350 mm no segundo, sendo cerca de 80% das mesmas de baixa intensidade (0-5 mm h-1). A interceptação foi de aproximadamente 25% da precipitação tanto pela cana-de-açúcar quanto pela floresta ripária. Os resultados de Ksat na área de cana-de-açúcar apontaram para a existência de camadas de impedimento próxima à superfície e como consequência os coeficientes de escoamento superficial foram superiores a outros usos do solo encontrados na literatura, bem como em relação à floresta ripária. Com isso, o fluxo direto representou cerca de 40% do deflúvio. A microbacia CCF não apresentou maior eficácia na diminuição do fluxo direto como era esperado, possivelmente, devido aos canais preferenciais gerados pelo lançamento pontual de água dos terraços. Os fluxos de entrada naturais de NID, NOD e COD nas microbacias foram relativamente baixos, sendo a principal via os fertilizantes (acima de 95%). As saídas desses elementos e compostos também foram baixas denotando que, possivelmente, as saídas dos mesmos nas microbacias se dão via queima pré-corte, ocorrida no primeiro ano de estudo, biomassa coletada e desnitrificação. Há evidências do papel da floresta ripária, presente em maior extensão na microbacia CCF, na diminuição do fluxo de N e COD dissolvidos nos riachos / Hydrological processes affect biogeochemical processes, because the movement of water in many compartments of the agroecossystem promotes elements redistribution. The transport of nitrogen (N) and dissolved organic carbon (DOC) in streams occur generally through runoff bringing negative implications for their water quality. Annual crops, such as sugarcane, require large amounts of inorganic and organic fertilizers that present N and DOC in their composition. Riparian forests play important roles related to quickflow generation and nutrient retention. These forests might maintain water quality in watersheds. In the present study, we determined the water balance and the fluxes of N and DOC in two watersheds covered by sugarcane. The first watershed presented riparian forest next to the creek in accordance with Brazilian legislation (CCF), and other watershed presented no riparian Forest in these conditions (CSF). The watersheds were instrumented to measure and collect hydrological data simultaneously and rain samples (inputs), and the streams (outputs) for N and DOC analysis. Each slope of the watersheds was divided into three parts: downslope, middleslope and upslope. All slopes parts, except the downslope at CCF, were covered by sugarcane. Downslope part CCF was under riparian forest. The hydrological monitoring occurred on a weekly basis during the first year and biweekly in the second year. The biogeochemical monitoring occurred on a weekly basis. To accomplish the mass balance the inputs of inorganic and organic fertilizers in the plantation were also computed. In first year, the rainfall was 1200 mm and in the second was 1350 mm. Around 80% of such precipitation was low intensity (0-5 mm h-1). The interception loss was approximately 25% of the rainfall either by sugarcane as the riparian forest. The Ksat results in the area of sugarcane showed the existence of impeding layers near the surface and consequently the overland flow coefficients were higher than other land uses available in the literature as well as in relation to riparian forest area. Thus, quickflow represented about 40% of the streamflow. The watershed CCF was not more effective in reducing the quickflow as expected, possibly due to preferential channels caused by the punctual release of water from the terraces. The natural input of NID, NOD and DOC in the watersheds were relatively low, with the fertilizers as the main source (above 95%). The outputs of these elements and compounds were also low denoting that the main outputs occur potentially by sugarcane pre-harvest burning, occurred in the first year, biomass harvested and denitrification process. However, there is evidence of the role of riparian forest, present to a greater extent in the watershed CCF, decreasing the output of N and DOC dissolved in streams

Os elevados custos de plantio e de manutenção de espécies nativas limitam a restauração florestal no Brasil. Buscando reduzir custos e acelerar a recuperação de vegetação ripária em região de cerrado, testou-se a utilização de espécie exótica de rápido crescimento (Pinus elliottii var. elliottii) como facilitadora da regeneração natural de espécies nativas lenhosas, no município de Assis, Estado de São Paulo, Brasil. A exploração de madeira e resina de Pinus poderia gerar receitas aos proprietários rurais e estimular ações de restauração com a compensação dos custos de plantio. Três tratamentos com plantio de Pinus nos espaçamentos 3 x 3 m, 3 x 2 m e 2 x 2 m, mais um quarto tratamento com áreas sem plantio (controle), foram instalados. Cada tratamento teve quatro repetições, em blocos ao acaso. Foram alocadas 16 parcelas (18 x 12 m cada) paralelamente ao rio, distando 20 a 40 m da margem. A área experimental fora utilizada como pastagem por duas décadas. Na ocasião do plantio (1995), predominavam gramíneas africanas. Plantas lenhosas e estruturas subterrâneas existentes foram preservadas. Avaliou-se área basal, cobertura de copas e sobrevivência das árvores plantadas, assim como composição florística, estrutura e cobertura de copas das plantas lenhosas em regeneração (altura mínima de 50 cm) em 1996, 1998, 1999, 2001 e 2006. Desejava-se verificar se: 1) Pinus facilitaria a regeneração da comunidade nativa; 2) Pinus dificultaria a regeneração da comunidade nativa ou 3) Pinus não alteraria a regeneração da comunidade nativa. Até 2006, a densidade média de plantas lenhosas regenerantes foi de 4923 ind/ha sob Pinus (maior quanto maior a densidade de Pinus) e de 3472 ind/ha no controle. Foram registradas 68 espécies lenhosas nativas em regeneração na área experimental, pertencentes a 31 famílias. Houve correlação positiva entre densidade das plantas regenerantes e densidade e área basal de Pinus, e correlação negativa entre parâmetros estruturais de Pinus e cobertura do terreno por gramíneas. Conclui-se que Pinus eliminou as gramíneas pelo sombreamento, favorecendo indiretamente as plantas nativas. Até 2006, não se constatou competição entre plantas nativas e Pinus pelos recursos do ambiente. Houve maior proporção de plantas zoocóricas regenerantes no controle, e correlação negativa entre proporção de regenerantes zoocóricos e parâmetros estruturais de Pinus. Foram favorecidas por Pinus 40% das espécies regenerantes e, 25%, prejudicadas. A sucessão deverá conduzir as duas situações a comunidades distintas, especialmente em função da tolerância das espécies à sombra, predominantes sob Pinus. A análise econômica do uso de Pinus elliottii como facilitadora da regeneração natural demonstrou menores custos de plantio (cerca de um terço dos custos de plantios mistos com espécies nativas), compensados por um ano de exploração de resina. Porém, as técnicas usuais de exploração podem danificar as plantas regenerantes do sub-bosque. Assim, a restauração da comunidade nativa exige meios menos impactantes de exploração dos plantios de espécies exóticas. / Among the obstacles to the native forests restoration in Brazil we find the high costs of planting high diversity of native trees. Searching for reduction of costs and vegetation recovery acceleration, the use of a fast growing exotic species (Pinus elliottii var. elliottii) as pioneer was tested in a riparian area in the cerrado domain, at Assis municipality, São Paulo State, Brazil. As observed in forest plantations with exotic species in the same region, we expected the natural regeneration of native species to occur under the planted exotic trees. In addition, the later exploitation of the exotic species could bring some profit to the land owner, surpassing the restoration costs, and thus stimulating forest restoration initiatives. Pinus was planted in three different spacings (treatments): 3 x 3 m, 3 x 2 m and 2 x 2 m, and a fourth treatment consisted of not planted plots (control). Every treatment had four replications in randomized blocks, the 16 plots (18 x 12 m each) settled along the stream, from 20 to 40 m far from the margin. The experimental area had been used as pasture for at least two decades, mostly covered by african grasses. Some native species then existing were preserved when the Pinus trees were planted, in 1995, without revolving the soil. Basal area, crown cover and survival of planted trees, as well as floristic composition, density and crown cover of native species regenerating in every plot (minimum height 50 cm) were assessed in 1996, 1998, 1999, 2001 and 2006. The aim was to verify if: 1) Pinus trees facilitating the regeneration of the native species, 2) Pinus trees obstructing the evolution of the native community or 3) the exotic species not affecting the native community. In 2006, density of the native woody species regenerating was 4923 ind/ha under Pinus and 3472 ind/ha in the control, from a total of 68 woody species (31 families) in the experimental area. Density of the regenerating community was positively correlated to density and basal area of Pinus. Thus, we concluded that Pinus eliminating grasses by shading (ground cover by grasses was inversely correlated to Pinus structure), indirectly favored the native woody species and are still not competing with them. The proportion of zoochorous species was negatively correlated to the Pinus density, showing that the exotic species does not attract animal seed dispersers. In the open areas (control), the zoochory was relatively more frequent. Density of some species (40%) increasing under Pinus and others (25%) decreasing or disappearing, which means secondary succession should go toward different directions if under Pinus plantation or in open areas. Analyzing the economical aspects of using Pinus as pioneer, we found that planting costs corresponded to a third part of those of planting mixed stands with native species. In addition, planting costs can be compensated by a single year of resin exploitation. However, current techniques of resin extraction or timber exploitation could cause considerable damages to the understory. Alternative exploitation techniques of the exotic species must be encouraged if restoration of the native community in the understory is expected.

Os processos hidrológicos afetam os processos biogeoquímicos, pois o movimento da água nos vários compartimentos do agroecossistema promove a redistribuição dos nutrientes, como o nitrogênio (N) e o carbono orgânico dissolvido (COD). O carreamento desse N e COD nos corpos hídricos se dão, normalmente, via escoamento superficial trazendo implicações negativas à sua qualidade. Em culturas anuais, como a cana-de-açúcar, há exigência de grande quantidade de fertilizantes inorgânicos e orgânicos que têm o N e o COD como os principais elementos. A floresta ripária desempenha funções relacionadas à geração do escoamento direto em microbacia e a retenção de nutrientes. Este trabalho tem como objetivo realizar o balanço hídrico e determinar o fluxo de N e COD em duas microbacias com cobertura de cana-de-açúcar, sendo que, uma microbacia apresenta floresta ripária próxima ao riacho em conformidade com a legislação vigente (Cana com floresta ripária - CCF) e a outra não apresenta floresta ripária nessas condições (Cana sem floresta ripária - CSF). Para tanto as microbacias foram instrumentalizadas para medir e coletar simultaneamente dados hidrológicos e amostras de chuva (entradas) e dos riachos (saídas) para análises de N e COD. As vertentes estudadas nas microbacias foram subdivididas em três porções: inferior, intermediária e superior, sendo que a primeira, na microbacia CCF encontra-se exclusivamente em floresta ripária. O monitoramento hidrológico ocorreu semanalmente no primeiro ano de estudo, e quinzenalmente no segundo. Já o monitoramento biogeoquímico das entradas e saídas ocorreu semanalmente. Para realizar o balanço de massa foram computadas as entradas via fertilizantes inorgânicos e orgânicos na cultura. A precipitação foi de 1200 mm no primeiro ano de estudo e 1350 mm no segundo, sendo cerca de 80% das mesmas de baixa intensidade (0-5 mm h-1). A interceptação foi de aproximadamente 25% da precipitação tanto pela cana-de-açúcar quanto pela floresta ripária. Os resultados de Ksat na área de cana-de-açúcar apontaram para a existência de camadas de impedimento próxima à superfície e como consequência os coeficientes de escoamento superficial foram superiores a outros usos do solo encontrados na literatura, bem como em relação à floresta ripária. Com isso, o fluxo direto representou cerca de 40% do deflúvio. A microbacia CCF não apresentou maior eficácia na diminuição do fluxo direto como era esperado, possivelmente, devido aos canais preferenciais gerados pelo lançamento pontual de água dos terraços. Os fluxos de entrada naturais de NID, NOD e COD nas microbacias foram relativamente baixos, sendo a principal via os fertilizantes (acima de 95%). As saídas desses elementos e compostos também foram baixas denotando que, possivelmente, as saídas dos mesmos nas microbacias se dão via queima pré-corte, ocorrida no primeiro ano de estudo, biomassa coletada e desnitrificação. Há evidências do papel da floresta ripária, presente em maior extensão na microbacia CCF, na diminuição do fluxo de N e COD dissolvidos nos riachos / Hydrological processes affect biogeochemical processes, because the movement of water in many compartments of the agroecossystem promotes elements redistribution. The transport of nitrogen (N) and dissolved organic carbon (DOC) in streams occur generally through runoff bringing negative implications for their water quality. Annual crops, such as sugarcane, require large amounts of inorganic and organic fertilizers that present N and DOC in their composition. Riparian forests play important roles related to quickflow generation and nutrient retention. These forests might maintain water quality in watersheds. In the present study, we determined the water balance and the fluxes of N and DOC in two watersheds covered by sugarcane. The first watershed presented riparian forest next to the creek in accordance with Brazilian legislation (CCF), and other watershed presented no riparian Forest in these conditions (CSF). The watersheds were instrumented to measure and collect hydrological data simultaneously and rain samples (inputs), and the streams (outputs) for N and DOC analysis. Each slope of the watersheds was divided into three parts: downslope, middleslope and upslope. All slopes parts, except the downslope at CCF, were covered by sugarcane. Downslope part CCF was under riparian forest. The hydrological monitoring occurred on a weekly basis during the first year and biweekly in the second year. The biogeochemical monitoring occurred on a weekly basis. To accomplish the mass balance the inputs of inorganic and organic fertilizers in the plantation were also computed. In first year, the rainfall was 1200 mm and in the second was 1350 mm. Around 80% of such precipitation was low intensity (0-5 mm h-1). The interception loss was approximately 25% of the rainfall either by sugarcane as the riparian forest. The Ksat results in the area of sugarcane showed the existence of impeding layers near the surface and consequently the overland flow coefficients were higher than other land uses available in the literature as well as in relation to riparian forest area. Thus, quickflow represented about 40% of the streamflow. The watershed CCF was not more effective in reducing the quickflow as expected, possibly due to preferential channels caused by the punctual release of water from the terraces. The natural input of NID, NOD and DOC in the watersheds were relatively low, with the fertilizers as the main source (above 95%). The outputs of these elements and compounds were also low denoting that the main outputs occur potentially by sugarcane pre-harvest burning, occurred in the first year, biomass harvested and denitrification process. However, there is evidence of the role of riparian forest, present to a greater extent in the watershed CCF, decreasing the output of N and DOC dissolved in streams

<p>The work in this thesis deals with (1) the effects of woody debris on stream channel morphology and retention of organic material, and (2) the dynamics of woody debris and its relation to riparian forest history and composition. The studied stream reaches are situated in mature, productive forests in the boreal zone of Sweden.</p><p>Wood variables were important predictors of the frequency of debris dams, pool area, the proportion of pools formed by wood, and variation in the bankfull channel width. Pools formed by woody debris were mainly created by damming and had larger surface areas and residual depths than pools formed by other agents. Stream reaches intersecting old-growth forest (with minor influence of forest management) had coarser and longer woody debris pieces, greater amounts of wood, more debris dams, and wood-formed pools compared to streams surrounded by forests influenced by selective logging.</p><p>The influence of past forest management on the quality and quantity of woody debris in streams were analyzed by using dendrochrnological methods. Selective loggings and absence of forest fires after 1831 resulted in lower input rates and a gradual replacement of pine by sruce over time. Residence times in stream channels of woody debris (>10 cm in basal diameter) were long and the oldest dated pieces of pine and spruce were over 300 and 100 years, respectively.</p><p>Dynamics of woody debris were explored by comparing wood volumes and characteristics between stream channels and their riparianforests and between old growth and managed sites. Wood volumes recorded in the stream channels exceeded, but were related to, the volumes found in the riparian forests. Limited input of woody debris by bank cutting and absence of slope processes suggest that recruitment processes of woody debri to stream channels are similar as in riparian forests and slow decay in channels results in greater volumes.</p><p>The retentiveness of organic material in stream channels was examined by using release and capture experiments in multiple reaces during varying discharges using different sizes of leaf mimics. Sixty eight percent of the variation in retention was explained by a multiple regression model including discharge and leaf mimic siz. Between 44 and 80% of the variation in retention among reaches was explained by channel constraint, gravel coverage, and woody debris variables as the most important. Estimates from a partial least squares (PLS) model suggest an increase in mean transport distances by 22 to 53% in managed forest streams compared to old growth conditions and in a low wood scenario, mean transport distances increased by 38 to 99% with larger increases for higher discharges and larger particle sizes.</p><p>To regain more pristine conditions of stream channels, management and restoration are needed to increase the amount of woody debris that recreates lost channel structures and increaes the retention of organic material.</p>

The work in this thesis deals with (1) the effects of woody debris on stream channel morphology and retention of organic material, and (2) the dynamics of woody debris and its relation to riparian forest history and composition. The studied stream reaches are situated in mature, productive forests in the boreal zone of Sweden. Wood variables were important predictors of the frequency of debris dams, pool area, the proportion of pools formed by wood, and variation in the bankfull channel width. Pools formed by woody debris were mainly created by damming and had larger surface areas and residual depths than pools formed by other agents. Stream reaches intersecting old-growth forest (with minor influence of forest management) had coarser and longer woody debris pieces, greater amounts of wood, more debris dams, and wood-formed pools compared to streams surrounded by forests influenced by selective logging. The influence of past forest management on the quality and quantity of woody debris in streams were analyzed by using dendrochrnological methods. Selective loggings and absence of forest fires after 1831 resulted in lower input rates and a gradual replacement of pine by sruce over time. Residence times in stream channels of woody debris (&gt;10 cm in basal diameter) were long and the oldest dated pieces of pine and spruce were over 300 and 100 years, respectively. Dynamics of woody debris were explored by comparing wood volumes and characteristics between stream channels and their riparianforests and between old growth and managed sites. Wood volumes recorded in the stream channels exceeded, but were related to, the volumes found in the riparian forests. Limited input of woody debris by bank cutting and absence of slope processes suggest that recruitment processes of woody debri to stream channels are similar as in riparian forests and slow decay in channels results in greater volumes. The retentiveness of organic material in stream channels was examined by using release and capture experiments in multiple reaces during varying discharges using different sizes of leaf mimics. Sixty eight percent of the variation in retention was explained by a multiple regression model including discharge and leaf mimic siz. Between 44 and 80% of the variation in retention among reaches was explained by channel constraint, gravel coverage, and woody debris variables as the most important. Estimates from a partial least squares (PLS) model suggest an increase in mean transport distances by 22 to 53% in managed forest streams compared to old growth conditions and in a low wood scenario, mean transport distances increased by 38 to 99% with larger increases for higher discharges and larger particle sizes. To regain more pristine conditions of stream channels, management and restoration are needed to increase the amount of woody debris that recreates lost channel structures and increaes the retention of organic material.