The interaction of agricultural fertilizer application and a drought-to-flood transition in 2012-2013 set up conditions for a watershed-scale experiment on nutrient dynamics. The region-wide drought in 2012 left surface soils disconnected from stream networks and restricted nutrient use by crops, resulting in an unusually large nitrogen pool stored in the soil column through the winter. The wet conditions in the Midwest in spring of 2013 mobilized the unused fertilizer from the landscape into the stream network. A six-week period of extremely high in-stream nutrient concentrations followed. This study analyzes results of three synoptic sampling campaigns in the Iowa-Cedar River Basin in 2013 to quantify patterns in nitrogen dynamics. I estimate nutrient spiraling metrics by interpreting the fertilizer mobilization from the landscape to the stream as a constant rate nutrient addition at the scale of the entire watershed—a vital scale on which to understand these processes, but for which costs and logistics of standard experiments are prohibitive. Results of this study compare patterns in dilution and uptake across spatial and temporal scales, and bound feasible explanations for hydrologic and reactive function in each reach of the network.

　　Cultural landscapes, as the products of long-term interaction between human and nature, have been increasingly recognized by different international bodies for their importance in heritage conservation. However, cultural landscapes usually do not enjoy specific protection and are subject to most dynamic landscape changes in modern society that impair the significance. The traditional agricultural areas in the New Territories, display unique features of organically evolved cultural landscape in Hong Kong, have disappeared in drastic rate in recent decades. Long Valley, as one of the remarkable local example of traditional agricultural landscape, was studied to illustrate the spatial and landownership transformation connected with socio-economical transition over the last century. Aerial photos comparison and Geographic Information System (GIS) were employed, and stakeholders’ interviews were conducted to aid landscape analysis. 　　 　　The significance of Long Valley is embodied in the setting, natural features, resources of land and cultural context associated with the indigenous settlement and farming tradition in Hong Kong. The long history of agriculture by indigenous clans and more recently by tenant farmers defines the major landscape features of Long Valley. The aerial photographs comparison revealed that road widening, river training works, urbanization, industrialization and infrastructure development during 1960s – 1990s caused drastic environmental change and direct loss of farmland area in and surrounding Long Valley. 　　 　　Combining current cadastral map with historic land plot records shows that the past lots boundaries are still influencing on today’s fieldscape of Long Valley. On the other hand, the landownership pattern of Long Valley is fragmented and complicated, and has changed continuously over the century. Indigenous clans have dominant ownership control of Long Valley but their influence is diminishing. Certain portion of lands has been transferred to developers’ and outsiders’ hands. The complicated and fragmented landownership, however, protects the site from being developed yet. 　　 　　Although conservation efforts have been paid by local NGOs and the Government, Long Valley is still under threats of illegal dumping and unauthorized land-use change initiated by some indigenous landowners as well as development pressure. Traditional agricultural landscapes represent part of local natural and cultural heritage and are key component of local indigenous identity which should receive proper attention and protection. Therefore, adequate conservation and agricultural policy, effective legislation enforcement and planning control, development of adaptive conservation strategies and engagement of local stakeholders are in urge to safeguard and sustain local traditional agricultural landscapes, as well as other significant rural landscapes in Hong Kong. / published_or_final_version / Conservation / Master / Master of Science in Conservation

No description available.

Intense agriculture is detrimental to the environment and leads to nutrient runoff, decreased water quality, soil erosion, greenhouse gas emissions, and decreased wildlife habitat. In addition to negative environmental impacts, intense agriculture increases the financial strain on farmers. Farmers also face inconsistent yields from environmentally vulnerable lands. Due to these financial constraints and inconsistent yields, conservation goals are not always economically attractive to farmers and agricultural producers. One possible solution to this issue is the use of precision agriculture (PA) to inform strategic conservation efforts. We used PA technology to identify low-revenue field areas in the Mississippi Delta and Black Prairie regions. We created spatially explicit revenue maps and overlaid it with the Biologist Ranking Index (BRI) to illustrate where economic and conservation opportunities overlap. Our results indicate that, on average, upwards of 20.1% of the Black Prairie and 18.0% of the Mississippi Delta generate less revenue than conservation enrollment.

Studies in agricultural landscapes have shown that anthropogenic environments may be relevant to wildlife species. Given the extent of these areas efficient research methods are needed to assess its ecological value in terms of local diversity, such as the use of biological indicators. The main goal here was to evaluate the possible relationship between the native vegetation biomass and diversity of small mammals in a silvicultural landscape of São Paulo. The study was developed at Fazenda Três Lagoas, which is part of the \"Programa de Pesquisa em Biodiversidade\" (PPBio), at Angatuba municipality, State of São Paulo, and lasted nine months. From May 2015 to March 2016 nine sampling campaigns were carried over a grid of 15 pitfall traps, five in Eucalyptus plantations, five in native vegetation and five in abandoned pastures. In the Chapter 1 the distribution and abundance patterns of small mammals on a silvicultural landcape during the early second cycle of Eucalyptus plantation in Southeastern Brazil was evaluated. A total of 672 individuals from 15 species of the orders Rodentia (9 spp.) and Didelphimorphia (6 spp.) were captured and five new species were detected in the study area in comparison to the first cycle. Although these species are predominantly generalists, there were differences in the abundance of small mammals in the three environments. The presence of native vegetation patches associated with riparian areas and abandoned pastures and the role of small mammals as a food resource for predators on a trophic structure, gives a certain conservation value to silvicultural landscapes in southeastern Brazil. In the Chapter 2 the relationship between landscape metrics and patterns of diversity, distribution and abundance of small mammals in a silvicultural landscape were evaluated. The species richness and family diversity of small mammals have been predominantly determined by the percentage of native vegetation. However, the abundance of small mammals can be determined by an indirect estimate of the native vegetation biomass (i.e., NDVI), which can be considered a 3D landscape metric as it is related to volume. Therefore, to succeed in assessing the value of agricultural landscape, future studies should consider landscape context, as well as the landscape metrics associated with geospatial data analysis and the distinct responses of species. / Estudos em paisagens agrícolas têm mostrado que ambientes antrópicos podem ser relevantes para muitas espécies selvagens. Dada a extensão destas áreas, são necessários métodos eficientes de pesquisa para avaliar seu valor ecológico em termos de diversidade local, tais como o uso de indicadores biológicos. O presente estudo teve como objetivo geral avaliar a possível relação entre a biomassa de vegetação nativa e a diversidade de mamíferos de pequeno porte em uma paisagem silvicultural do estado de São Paulo. O estudo foi desenvolvido na Fazenda Três Lagoas, que é parte do Núcleo Angatuba do Programa de Pesquisa em Biodiversidade (PPBio), no município de Angatuba, Estado de São Paulo e teve a duração de nove meses. De maio de 2015 a março de 2016, foram realizadas campanhas mensais de amostragem em uma grade amostral com 15 conjuntos de armadilhas de interceptação e queda (pitfall), sendo cinco nas plantações de Eucalyptus spp., cinco em vegetação nativa e cinco em pasto abandonado. No Capítulo 1 foram avaliados os padrões de distribuição e abundância de pequenos mamíferos em uma paisagem silvicultural ao início do segundo ciclo de plantações de Eucalyptus no Sudeste do Brasil. Um total de 672 indivíduos de 15 espécies das ordens Rodentia (9 spp.) e Didelphimorphia (6 spp.) foram capturados e cinco novas espécies foram detectadas na área de estudo em relação ao primeiro ciclo. Embora as espécies presentes sejam predominantemente generalistas, houve diferença na abundância de pequenos mamíferos nos três ambientes. A presença de fragmentos de vegetação nativa associados a áreas ripícolas e pasto abandonado e o papel dos pequenos mamíferos como recurso alimentar para predadores em uma estrutura trófica, atribui um valor de conservação às paisagens silviculturais no sudeste do Brasil. No Capítulo 2, o objetivo foi avaliar a relação entre métricas da paisagem e padrões de diversidade, distribuição e abundância de pequenos mamíferos em uma paisagem silvícultural. A riqueza de espécies e a diversidade de famílias dos pequenos mamíferos tem sido predominantemente determinada pela área porcentual de vegetação nativa. No entanto, a abundância de pequenos mamíferos pode ser determinada por uma estimativa indireta da biomassa da vegetação nativa (e.g., NDVI), que pode ser considerada uma métrica de paisagem 3D, pois está relacionada ao volume. Portanto, para ter sucesso na avaliação do valor da paisagem agrícola, os estudos futuros devem considerar o contexto da paisagem, bem como as métricas da paisagem associadas à análise dos dados geoespaciais e as distintas respostas das espécies.

Agricultural environments are critical to the conservation of biota throughout the world. This is due both to the limited extent of current reserve systems and the large, and still expanding, proportion of terrestrial environments already dominated by agricultural land-uses. Consequently, there is a growing call from scientists around the world for the need to maximise the conservation value of agricultural environments. Efforts to identify key influences on the conservation status of fauna in agricultural landscapes have taken complementary approaches. Many studies have focussed on the role of remnant or semi-natural vegetation, and emphasised the influence on biota of spatial patterns in the landscape. Others have recognised that many species use diverse ‘countryside’ elements (matrix habitats) within farmland, and emphasise the benefits of landscape heterogeneity for conservation. Here, these research themes have been combined. This study takes a whole-of-landscape approach to investigating how landscape pattern and countryside heterogeneity influence the occurrence of birds in agricultural environments. Birds were sampled in 27 agricultural mosaics, each 1 km x 1 km in size (100 ha), in Gippsland, south-eastern Australia. Mosaics were selected to incorporate variation in two landscape properties: the cover of native vegetation, and richness of different types of element (i.e. land-uses/vegetation types). In each mosaic, 15 fixed sampling locations were stratified among seven different elements in proportion to their cover in the mosaic: native vegetation, linear vegetation, tree plantation, scattered paddock trees, pasture, wetlands and farm dams. Six point counts of birds were undertaken at all sample points in each mosaic: three each in the breeding and non-breeding months of a one-year period (October 2004 – August 2005). Independent measures of the composition, configuration, and heterogeneity of elements in the mosaic had differing effects on the richness of bird species recorded in these same mosaics. Sub-groups of birds based on habitat requirements responded most strongly to the extent of preferred element types in mosaics. Woodland birds (those of greatest conservation concern in farmland environments in Australia) were richer in mosaics with higher cover of native vegetation while open-tolerant species responded to the extent of scattered trees. In contrast, for total species richness, mosaic heterogeneity (richness of element types) and landscape context (cover of native vegetation in surrounding area) had the greatest influence. Mosaic structural properties also influenced the composition of entire bird assemblages in study mosaics. Avifaunal composition showed systematic variation along two main gradients which were readily interpreted in relation to landscape properties: 1) a gradient in the cover of wooded vegetation and, 2) the proportional composition of vegetation types in the mosaic. These gradients represent common trajectories of landscape modification associated with agricultural development: namely, the removal of wooded vegetation and the replacement of native species with exotic vegetation (e.g. crops and plantations). Species possessing different characteristics in relation to three avian life-history traits (nest type, feeding guild and clutch size) varied significantly in their position along these gradients of landscape modification. Species with different nesting requirements showed a strong relationship with the gradient in wooded vegetation cover while species belonging to different feeding guilds were influenced by the gradient defined by the replacement of native vegetation with exotic species. More bird species were recorded in native vegetation than in any other type of element sampled in this study. Nevertheless, most countryside elements had value for many species; particularly structurally complex elements such as scattered trees and tree plantation. Further, each type of landscape element contained different bird assemblages. Species that were recorded in a greater number of different types of landscape element were also recorded in more mosaics. This was true for all species and for woodland birds, and indicates that species that can use a greater range of countryside elements may have an increased tolerance of future landscape modification. The richness of woodland species at survey sites in different elements was influenced by features of the mosaic in which they occurred. Notably, the richness of woodland bird species recorded at sites in scattered trees and pasture increased with a greater cover of native vegetation in the overall mosaic. Of the overall pool of woodland bird species documented in the broader study region, 35% of species were not recorded in the agricultural mosaics sampled here. While many of these species were uncommon in the study area, or were associated with vegetation communities infrequently sampled in mosaics, this shows that conservation efforts in agricultural landscapes will not be appropriate for all species. For those woodland species that were recorded, measures of the extent of wooded vegetation cover had a strong, positive influence on the frequency of occurrence of individual species in mosaics. Thus, individual species of woodland bird occurred more frequently in mosaics with a greater cover of wooded vegetation. Nine woodland species showed a stronger response to measures of vegetation cover that included tree plantation and/or scattered trees than to the cover of native vegetation alone. For these species, structurally complex countryside elements provide valuable supplementary habitat at the landscape scale. Results of this study show that landscape properties influence the occurrence of birds in agricultural mosaics. The extent of cover of element types, particularly native vegetation, had the strongest influence on all measures of bird occurrence in mosaics. Thus, native vegetation is vital for the persistence of birds in farmland landscapes and is the primary element on which conservation efforts in these environments depend. Nevertheless, with careful management, countryside elements may provide additional conservation benefits for many bird species. Countryside elements made an important contribution to landscape heterogeneity, the landscape property with greatest influence on overall bird richness in mosaics. Countryside elements also increased the structural complexity of cleared agricultural land, and so have the capacity to enhance connectivity in fragmented landscapes. A focus on these factors (landscape heterogeneity and structural complexity) will provide the greatest opportunities for using countryside elements to increase the conservation value of farmland environments for native fauna. The relatively small scale of this study indicates that the cumulative effect of even small elements in farm mosaics contributes to the structural properties of entire landscapes. Critically, this emphasises the important contribution that individual landholders can make to nature conservation in agricultural environments.

Studies in agricultural landscapes have shown that anthropogenic environments may be relevant to wildlife species. Given the extent of these areas efficient research methods are needed to assess its ecological value in terms of local diversity, such as the use of biological indicators. The main goal here was to evaluate the possible relationship between the native vegetation biomass and diversity of small mammals in a silvicultural landscape of São Paulo. The study was developed at Fazenda Três Lagoas, which is part of the \"Programa de Pesquisa em Biodiversidade\" (PPBio), at Angatuba municipality, State of São Paulo, and lasted nine months. From May 2015 to March 2016 nine sampling campaigns were carried over a grid of 15 pitfall traps, five in Eucalyptus plantations, five in native vegetation and five in abandoned pastures. In the Chapter 1 the distribution and abundance patterns of small mammals on a silvicultural landcape during the early second cycle of Eucalyptus plantation in Southeastern Brazil was evaluated. A total of 672 individuals from 15 species of the orders Rodentia (9 spp.) and Didelphimorphia (6 spp.) were captured and five new species were detected in the study area in comparison to the first cycle. Although these species are predominantly generalists, there were differences in the abundance of small mammals in the three environments. The presence of native vegetation patches associated with riparian areas and abandoned pastures and the role of small mammals as a food resource for predators on a trophic structure, gives a certain conservation value to silvicultural landscapes in southeastern Brazil. In the Chapter 2 the relationship between landscape metrics and patterns of diversity, distribution and abundance of small mammals in a silvicultural landscape were evaluated. The species richness and family diversity of small mammals have been predominantly determined by the percentage of native vegetation. However, the abundance of small mammals can be determined by an indirect estimate of the native vegetation biomass (i.e., NDVI), which can be considered a 3D landscape metric as it is related to volume. Therefore, to succeed in assessing the value of agricultural landscape, future studies should consider landscape context, as well as the landscape metrics associated with geospatial data analysis and the distinct responses of species. / Estudos em paisagens agrícolas têm mostrado que ambientes antrópicos podem ser relevantes para muitas espécies selvagens. Dada a extensão destas áreas, são necessários métodos eficientes de pesquisa para avaliar seu valor ecológico em termos de diversidade local, tais como o uso de indicadores biológicos. O presente estudo teve como objetivo geral avaliar a possível relação entre a biomassa de vegetação nativa e a diversidade de mamíferos de pequeno porte em uma paisagem silvicultural do estado de São Paulo. O estudo foi desenvolvido na Fazenda Três Lagoas, que é parte do Núcleo Angatuba do Programa de Pesquisa em Biodiversidade (PPBio), no município de Angatuba, Estado de São Paulo e teve a duração de nove meses. De maio de 2015 a março de 2016, foram realizadas campanhas mensais de amostragem em uma grade amostral com 15 conjuntos de armadilhas de interceptação e queda (pitfall), sendo cinco nas plantações de Eucalyptus spp., cinco em vegetação nativa e cinco em pasto abandonado. No Capítulo 1 foram avaliados os padrões de distribuição e abundância de pequenos mamíferos em uma paisagem silvicultural ao início do segundo ciclo de plantações de Eucalyptus no Sudeste do Brasil. Um total de 672 indivíduos de 15 espécies das ordens Rodentia (9 spp.) e Didelphimorphia (6 spp.) foram capturados e cinco novas espécies foram detectadas na área de estudo em relação ao primeiro ciclo. Embora as espécies presentes sejam predominantemente generalistas, houve diferença na abundância de pequenos mamíferos nos três ambientes. A presença de fragmentos de vegetação nativa associados a áreas ripícolas e pasto abandonado e o papel dos pequenos mamíferos como recurso alimentar para predadores em uma estrutura trófica, atribui um valor de conservação às paisagens silviculturais no sudeste do Brasil. No Capítulo 2, o objetivo foi avaliar a relação entre métricas da paisagem e padrões de diversidade, distribuição e abundância de pequenos mamíferos em uma paisagem silvícultural. A riqueza de espécies e a diversidade de famílias dos pequenos mamíferos tem sido predominantemente determinada pela área porcentual de vegetação nativa. No entanto, a abundância de pequenos mamíferos pode ser determinada por uma estimativa indireta da biomassa da vegetação nativa (e.g., NDVI), que pode ser considerada uma métrica de paisagem 3D, pois está relacionada ao volume. Portanto, para ter sucesso na avaliação do valor da paisagem agrícola, os estudos futuros devem considerar o contexto da paisagem, bem como as métricas da paisagem associadas à análise dos dados geoespaciais e as distintas respostas das espécies.

Historicamente, a produção de alimentos básicos no Brasil está associada à agricultura familiar. Atualmente, vigora um novo olhar sobre essa produção quando entram em cena outros componentes: a produção de commodities e a conservação ambiental. Conflitantes entre si, eles parecem não influenciar diretamente no modo com que a população do meio rural percebe as supostas relações de perdas no meio ambiente ou na biodiversidade. A partir dessas considerações, observamos que na Bacia do Corumbataí, com as mudanças no uso da terra nos últimos trinta anos, a agricultura familiar tem se modificado, assumindo diferentes configurações e variando segundo o tamanho das propriedades, tipos de produções e relações diferenciadas que essas têm com o meio ambiente. Sabemos que a compreensão da dimensão humana promove habilidades para responder à variedade de interesses sociais, científicos e políticos na conservação da natureza. Algumas dessas dimensões são: as atitudes, os valores, o comportamento, as características socioeconômicas, a demografia, entre outras que devem integrar as ciências sociais e a ecologia para a interdisciplinaridade da conservação. É nesse sentido que entendemos que as soluções para a crise de biodiversidade no meio rural serão geradas a partir do trabalho conjunto entre cientistas naturais e sociais em projetos interdisciplinares. Ainda que alguns trabalhos caminhem nesta direção, não existe nos estudos em agroecossistemas da Bacia do Corumbataí uma ponte que una componente humano e conservação. Para a região estudada, não há, a priori, respostas para estas questões, mas acreditamos que o desafio em conservar a biodiversidade está no balanço entre as metas ecológicas e as necessidades sociais, econômicas e políticas, havendo urgência na integração entre a comunidade local, pesquisadores e governança. Em termos de Bacia hidrográfica, a do Corumbataí é uma das regiões mais estudadas do meio científico, mas todo conhecimento gerado pouco tem contribuído para a conservação com vista à sustentabilidade tanto ambiental, quanto social. Portanto, o processo e construção de diálogo entre disciplinas firmemente estabelecidas na sua identidade teórica e metodológica, foi definitivamente nossa vocação neste trabalho. À luz dessas considerações, podemos sustentar que a atividade, o conhecimento e a vivência do pequeno produtor rural são de fundamental importância para a sua manutenção no campo, bem como para a pesquisa e a própria conservação dos recursos naturais na região. Os resultados desta tese apontam que as pesquisas de interação social e ambiental, tendo como agente facilitador à agricultura familiar geram perspectivas reais para desenvolvimento social e para conservação ambiental local. / Currently we have a new look on production, when other components such as the production of commodities and environmental conservation come into this scenario. Dichotomous each other, they do not seem to directly influence the way the rural population notice the alleged loss relationships in the environment or biodiversity. From these considerations we see that the Corumbataí basin with changes in land use over the last thirty years, the family farm has changed, assuming different configurations and varying according to the size of the properties, types of productions and different relationships between them and the environment. We know that understand the human dimension promotes skills to respond to the variety of social, scientific and political interests in nature conservation. Some of these dimensions are: the attitudes, valuesbehaviour, socioeconomic characteristics, demography, among others that must be included in the social sciences and ecology to a interdisciplinary conservation. That is why we believe that the solutions to the biodiversity crisis in rural areas will be generated from a combined work between natural and social scientists in interdisciplinary projects. Although some works walk in that direction, in agroecosystems studies in the Corumbataí basin there is not a bridge that join the human component and conservation. For the studied area, there are no a priori answers to these questions, but we believe that the challenge in biodiversity conservation is in the ecological balance between the goals and the social, economic and political needs, with urgency in the integration between the local community, researchers and governance. In terms of watershed, the Corumbataí basin is one of the most studied regions, but all knowledge generated has little contribution to the conservation for environmental and social sustainability. Therefore, the process and construction of the dialogue between disciplines firmly established in its theoretical and methodological identity was definitely our vocation in this work. So we hold that the activity, knowledge and experience of small farmers are essential to their maintenance in the field, as well as for research and self-preservation of natural resources in the region. The results of this thesis suggest that studies of environmental and social interaction, with as facilitator a family farms, generate real prospects for social development and environmental conservation site.

Este estudo enfocou a importância do contexto de ambientes alterados do entorno para a distribuição de diferentes grupos de espécies de pequenos mamíferos não-voadores em paisagens fragmentadas de Mata Atlântica. Na primeira abordagem (capítulo 2), usando a distribuição de pequenos mamíferos em remanescentes florestais e nos quatro principais habitats alterados de uma paisagem de Mata Atlântica, investigamos (1) como o poder explanatório dos modelos que descrevem a distribuição das espécies em fragmentos florestais varia entre as variáveis da estrutura da paisagem que incorporam ou não a qualidade da matriz e (2) a importância da escala espacial para analisar a influência da estrutura da paisagem. Usamos amostragem padronizada nos remanescentes e habitats alterados para gerar dois índices de qualidade de habitat, correspondentes à abundância e à ocorrência de pequenos mamíferos. Para cada remanescente, calculamos a quantidade de habitat e a conectividade em diferentes escalas espaciais, considerando ou não a qualidade dos habitats ao redor. A incorporação da qualidade da matriz aumentou o poder explanatório dos modelos para todas as escalas espaciais para metade das espécies que ocorreram na matriz, mas apenas quando consideramos a distância entre as manchas de habitat (conectividade). Os resultados indicam a importância da matriz para a dinâmica de paisagens fragmentadas e sugere que índices relativamente simples podem melhorar nosso entendimento sobre a distribuição das espécies, e poderiam ser aplicados na modelagem, monitoramento e manejo de paisagens tropicais complexas. Na segunda abordagem (capítulo 3), testamos duas hipóteses relacionadas à importância do contexto da paisagem para a diversidade biológica encontrada em áreas agrícolas usando os pequenos mamíferos da Mata Atlântica como modelo: (1) que o contexto em que cultivos agrícolas estão inseridos, em particular a quantidade de florestas remanescentes, determina a assembléia de pequenos mamíferos encontrada nestas áreas produtivas; (2) que essas respostas ao contexto são escala-dependentes, sendo observadas em escalas espaciais mais amplas. Para tanto, amostramos 36 sítios em áreas agrícolas em duas paisagens fragmentadas de Mata Atlântica com diferentes proporções de florestas nativas remanescentes, os quais foram selecionados de forma a abranger ampla variação na quantidade e agregação de áreas abertas no entorno imediato. Construímos e comparamos 12 modelos candidatos que diferem quanto à contribuição dos efeitos do contexto em escala espacial ampla e em escala local, incluindo todas as combinações possíveis entre essas variáveis, a interação das variáveis medidas em diferentes escalas, e um modelo nulo. De acordo com as expectativas iniciais, as espécies restritas a biomas florestais foram mais comuns e bem distribuídas em áreas agrícolas circundadas por maiores quantidades de floresta em escala ampla. No entanto, as espécies invasoras e não-restritas a biomas florestais dominaram as áreas agrícolas das duas paisagens estudadas, independentemente da quantidade de floresta remanescente em escala ampla, tendo respondido principalmente, mas de maneira oposta, ao contexto em escalas menores. Os resultados indicam que: (1) a resposta diferencial entre os grupos de espécies é condicionada por diferenças nos requerimentos de habitat entre eles; (2) a manutenção de espécies mais exigentes em áreas agrícolas depende de estratégias de manejo que considerem a escala da paisagem; (3) mesmo áreas de agricultura convencional podem ser importantes para a conectividade da paisagem para espécies exigentes, desde que inseridas em contexto de maior quantidade de matas remanescentes; (4) o controle das populações de espécies invasoras que podem atuar como reservatórios de patógenos causadores de doenças no homem e pestes na agricultura depende de manejo em escala local, pelo menos em paisagens onde as áreas agrícolas são predominantes. / This study focused on the importance of the context of altered habitats in the neighborhoods to the distribution of different groups of species of non-flying small mammals in fragmented landscapes of the Atlantic forest. In the first approach (chapter 2), using the distribution of small mammals in forest remnants and in the four main altered habitats in an Atlantic forest landscape, we investigated 1) how explanatory power of models describing species distribution in forest remnants varies between landscape structure variables that do or do not incorporate matrix quality and 2) the importance of spatial scale for analyzing the influence of landscape structure. We used standardized sampling in remnants and altered habitats to generate two indices of habitat quality, corresponding to the abundance and to the occurrence of small mammals. For each remnant, we calculated habitat quantity and connectivity in different spatial scales, considering or not the quality of surrounding habitats. The incorporation of matrix quality increased model explanatory power across all spatial scales for half the species that occurred in the matrix, but only when taking into account the distance between habitat patches (connectivity). Results indicate the importance of the matrix for the dynamics of fragmented landscapes and suggest that relatively simple indices can improve our understanding of species distribution, and could be applied in modeling, monitoring and managing complex tropical landscapes. In the second approach, (chapter 3), we aimed at testing two hypotheses related to the importance of landscape context to the biological diversity found in areas of agriculture using Atlantic forest small mammals as a model: (1) that the context in which the areas of agriculture are inserted, in particular the quantity of remnant forests, determines the assemblage of small mammals found in those productive areas; (2) that those responses to the context are scale-dependent, being observed at larger spatial scales. To accomplish that, we sampled 36 sites in areas of agriculture in two fragmented Atlantic forest landscapes presenting different proportions of native forest remnants, which were selected aiming at including the widest variation in quantity and aggregation of open anthropogenic areas in the local neighborhood. We built and compared 12 candidate models which differed in relation to the contribution of the effects of context at large and local spatial scales, including all possible combinations between these variables, the interaction of the variables measured at different scales, and the null model. According to our initial expectations, the species that are restricted to forest biomes were the commonest and best-distributed ones, in areas of agriculture surrounded by higher quantities of forest at the large scale. However, the invasive species and the species that are not restricted to forest biomes dominated the areas of agriculture in the two studied landscapes, independently from the quantity of remnant forest at the large scale, and they responded mainly, but in the opposite way, to the context at smaller scales. The results indicate that: (1) the differential response between the groups of species is conditioned by differences in habitat requirements between them; (2) the maintenance of more demanding species in agricultural lands depends on management strategies which consider the landscape scale; (3) even areas of conventional agriculture can be important to the connectivity of the landscape for the most demanding species, as far as they are inserted in a context of higher quantities of remnant forest; (4) the control of the populations of invasive species that can act as reservoirs of pathogens that cause disease in men, and that can be pests in agriculture, depends on the management at local scale, at least in landscapes where the areas of agriculture predominate.

L'agriculture actuelle est impliquée dans de multiples problématiques environnementales, sociales et économiques, aux échelles locales et globales. En agronomie, de nombreux travaux à l'échelle du champ et de l'exploitation visent aujourd'hui à concevoir des systèmes de culture et des systèmes de production en lien avec ces problématiques. En revanche, peu de travaux portent sur la conception et l'évaluation de systèmes agricoles à l'échelle du territoire, alors que cette échelle apparaît pourtant incontournable pour faire face à des enjeux de développement durable. Pour combler ce manque, nous proposons un ensemble méthodologique permettant i) de simuler les conséquences de scénarios de politiques agricoles sur les choix d'assolement des agriculteurs, décrits individuellement, en modélisant l'évolution de leurs système de production et ii) d'évaluer l'impact de ces changements d'assolements à l'échelle du territoire, à l'aide d'indicateurs qui apportent de l'information spatiale sur la contribution de l'agriculture au développement durable. L'ensemble méthodologique proposé débute par la construction d'une typologie des exploitations agricoles du territoire sur la base de la similarité de leur assolement. Parallèlement, l'adaptation d'indicateurs à l'échelle du territoire permet d'évaluer les impacts des externalités des systèmes de culture en mobilisant des procédures de changements d'échelles. Un modèle bioéconomique générique, multi-échelle, spatialement explicite, appelé MOSAICA, qui utilise la typologie et les indicateurs d'impact de l'agriculture à l'échelle régionale, est créé pour produire des mosaïques de systèmes de culture et évalue leur contribution au développement durable du territoire. Ce modèle, couplé à un itinéraire de définition de scénarios exploratoires et normatifs permet de tester l'impact de différents types de leviers agronomiques, socio-économiques, environnementaux, organisationnels et techniques sur les choix des exploitants et in fine sur la contribution de la mosaïque de systèmes de culture au développement durable du territoire. Nous avons appliqué cet ensemble méthodologique à la conception de scénarios de développement agricoles durables en Guadeloupe. Nous avons dans un premier temps développé une typologie des systèmes de production comprenant huit types distincts et relevant de processus décisionnel différents. Puis nous avons adapté à l'échelle du territoire 19 indicateurs pour l'évaluation des mosaïques de systèmes de culture. L’évaluation de la mosaïque actuelle nous a permis de repérer de faibles niveaux de contribution aux enjeux d’autonomie alimentaire et énergétique. Différents scénarios normatifs et exploratoires intégrant des leviers de changement de la mosaïque ont été testés avec MOSAICA. Les évaluations réalisées nous ont permis d'identifier que des leviers agronomiques comme le développement du maraîchage sans intrants chimiques et des leviers sociaux comme la formation de main-d'oeuvre supplémentaire permettraient d'améliorer la contribution de l’agriculture au développement durable du territoire Guadeloupéen. La modélisation mécaniste de l’évolution du territoire agricole permet d'intégrer des connaissances sur la localisation, les performances, les impacts des systèmes de culture et sur les processus décisionnels des exploitants régissant l’orientation productive et le fonctionnement des exploitations. Cette démarche permet de visualiser les changements de système de culture et leurs impacts de manière spatialement explicite, ce qui permet de générer des connaissances sur les leviers susceptibles de faire évoluer positivement l'agriculture du territoire. La démarche et les outils mis en oeuvre sont donc particulièrement utiles pour l'aide à la décision publique pour améliorer la durabilité de l'agriculture dans son ensemble. / Current agricultural systems are responsible for many different environmental, social and economic issues at both local and global scales. Agricultural sciences have contributed to the design of several methods at the farm and field scale in order to prototype cropping systems and farming systems to address these issues. However, few methods have been designed at the regional scale, while this scale seems to be essential in order to address these issues. In order to fill this gap, we here propose a new methodological framework for i) simulating the consequences of policy changes on farmer's cropping plan, described individually, by modeling the evolution of farming systems and to ii) assess the impacts of cropping system changes at the regional scale, with a set of indicators that generate spatially explicit information on the contribution of agriculture to sustainable development. The methodological framework starts with the design of a farm typology over the territory based on the similarity of farmer's crop acreages. In parallel, a set of indicators is adapted to the landscape scale in order to assess the impacts of cropping system externalities by integrating a set of scale change procedures. A generic, multi-scale, spatially explicit bioeconomic model called MOSAICA, which uses the farm typology and the indicators, is created for generating cropping system mosaics and assessing their contribution to sustainable development. This model coupled to a scenario approach composed of exploratory and normative scenarios can simulate the impact of several types of agronomic, socio-economic, environmental, organizational and technical levers of change on the farmer's choices in terms of cropping systems and in fine the impacts of new cropping system mosaics on the contribution to sustainable development of territories. We applied this methodological framework for building scenarios of sustainable agricultural development in Guadeloupe. We first developed a typology of farming systems encompassing eight types of farming systems that revealed several different farmer's decision processes. Then, we developed 19 indicators to assess cropping system mosaics. The assessment of the current cropping system mosaic showed low levels of response of the current mosaic to economic and social issues especially the food and energy self-sufficiency. Different normative and exploratory scenarios integrating levers of change have been simulated with MOSAICA. The assessment of cropping system mosaics from these scenarios highlighted the positive effect of agronomic levers of change such as organic crop-gardening and social levers such as the vocational training of supplementary workforce for improving the contribution of agriculture to sustainable development of the guadeloupean territory. The mechanistic modeling of the agricultural territory allows us to integrate a wide range of knowledge on the location of cropping systems, their levels of performance , their impacts and the decision process of farmer's that drive the farming system characteristics and the farm functioning. This methodological framework helps visualize the cropping system changes at the regional scale and their associated impacts at the landscape scale which is helpful in order to produce knowledge on the levers of change that can improve the response of local agriculture to local and global issues. The framework and tools designed are particularly useful for decision-aid on the future levels of contribution of agriculture to sustainable development.