865 resultados para Net Income from Land Use
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Land tenure insecurity is widely perceived as a disincentive for long-term land improvement investment hence the objective of this paper is to evaluate how tenure (in)security associated with different land use arrangements in Ghana influenced households plot level investment decisions and choices. The paper uses data from the Farmer-Based Organisations (FBO) survey. The FBO survey collected information from 2,928 households across three ecological zones of Ghana using multistaged cluster sampling. Probit and Tobit models tested the effects of land tenancy and ownership arrangements on households investment behaviour while controlling other factors. It was found that marginal farm size was inversely related to tenure insecurity while tenure insecurity correlate positively with value of farm land and not farm size. Individual ownership and documentation of land significantly reduced the probability of households losing uncultivated lands. Individual land ownership increased both the probability of investing and level of investments made in land improvement and irrigation probably due to increasing importance households place on land ownership. Two possible explanations for this finding are: First, that land markets and land relations have changed significantly over the last two decades with increasing money transaction and fixed agreements propelled by population growth and increasing value of land. Secondly, inclusion of irrigation investment as a long term investment in land raises the value of household investment and the time period required to reap the returns on the investments. Households take land ownership and duration of tenancy into consideration if the resource implications of land investments are relatively huge and the time dimension for harvesting returns to investments is relatively long.
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Artisanal columbite-tantalite (coltan) mining has had negative effects on the rural economy in the great Lakes region of Africa through labor deficits, degradation and loss of farmland, food insecurity, high cost of living, and reduced traditional export crop production alongside secondary impacts that remotely affect the quality of air, water, soil, plants, animals, and human wellbeing. The situation is multifaceted and calls for a holistic approach for short and long-term mitigation of such negative effects. This study focuses on the effects of mine land restoration on soil microbiological quality in the Gatumba Mining District of western Rwanda. Some coltan mine wastelands were afforested with pine and eucalyptus trees while farmers directly cultivated others due to land scarcity. Farmyard manure (FYM) is the sole fertilizer applied on the wastelands although it is insufficient to achieve the desired crop yields. Despite this, several multi-purpose plants such as Tithonia diversifolia, Markhamia lutea, and Canavalia brasiliensis thrive in the area and could supplement FYM. The potential for these new amendments to improve soil microbial properties, particularly in the tantalite mine soils was investigated. The specific objectives of the study were to: (a) evaluate the effects of land use on soil microbial indices of the tantalite mine soils; (b) investigate the restorative effects of organic amendments on a Technosol; and (c) estimate the short-term N and P supply potential of the soil amendments in the soils. Fresh soils (0-20 cm) from an unmined native forest, two mine sites afforested with pine and eucalyptus forests (pine and eucalyptus Technosols), an arable land, and two cultivated Technosols (Kavumu and Kirengo Technosols) were analyzed for the physicochemical properties. Afterwards, a 28-day incubation (22oC) experiment was conducted followed by measurements of mineral N, soil microbial biomass C, N, P, and fungal ergosterol contents using standard methods. This was followed by a 12-week incubation study of the arable soil and the Kavumu Technosol amended with FYM, Canavalia and Tithonia biomass, and Markhamia leaf litter after which soil microbial properties were measured at 2, 8, and 12 weeks of incubation. Finally, two 4-week incubation experiments each were conducted in soils of the six sites to estimate (i) potential mineralizable N using a soil-sand mixture (1:1) amended with Canavalia and goat manure and (ii) P mineralization mixtures (1:1) of soil and anion exchange resins in bicarbonate form amended with Tithonia biomass and goat manure. In study one, afforestation increased soil organic carbon and total N contents in the pine and eucalyptus Technosols by 34-40% and 28-30%, respectively of that in the native forest soil. Consequently, the microbial biomass and activity followed a similar trend where the cultivated Technosols were inferior to the afforested ones. The microbial indices of the mine soils were constrained by soil acidity, dithionite-extractable Al, and low P availability. In study two, the amendments substantially increased C and N mineralization, microbial properties compared with non-amended soils. Canavalia biomass increased CO2 efflux by 340%, net N mineralization by 30-140%, and microbial biomass C and N by 240-600% and 240-380% (P < 0.01), respectively after four weeks of incubation compared with the non-amended soils. Tithonia biomass increased ergosterol content by roughly 240%. The Kavumu Technosol showed a high potential for quick restoration of its soil quality due to its major responses to the measured biological parameters. In study three, Canavalia biomass gave the highest mineralizable N (130 g g-1 soil, P < 0.01) in the Kavumu Technosol and the lowest in the native forest soil (-20 g g-1 soil). Conversely, the mineralizable N of goat manure was negative in all soils ranging from -2.5 g N g-1 to -7.7 g N g-1 soil except the native forest soil. However, the immobilization of goat manure N in the cultivated soils was 30-70% lower than in the forest soils signifying an imminent recovery of the amended soils from N immobilization. The mineralization of goat manure P was three-fold that of Tithonia, constituting 61-71% of total P applied. Phosphorus mineralization slightly decreased after four weeks of incubation due to sulfate competition as reflected in a negative correlation, which was steeper in the Tithonia treatment. In conclusion, each amendment used in this research played a unique role in C, N, and P mineralization and contributed substantially to microbial properties in the tantalite mine soils. Interestingly, the N immobilizers exhibited potentials for P release and soil organic carbon storage. Consequently, the combined use of the amendments in specific ratios, or co-composting prior to application is recommended to optimize nutrient release, microbial biomass dynamics and soil organic matter accrual. Transport of organic inputs seems more feasible for smallholder farmers who typically manage small field sizes. To reduce acidity in the soils, liming with wood ash was recommended to also improve P availability and enhance soil biological quality, even if it may only be possible on small areas. Further, afforestation with mixed-species of fast-growing eucalyptus and legume or indigenous tree species are suggested to restore tantalite mine wastelands. It is emphasized most of this research was conducted under controlled laboratory conditions, which exclude interaction with environmental variables. Also fine fractions of the amendments were used compared with the usual practice of applying a mixture of predominantly coarser fractions. Therefore, the biological dynamics reported in the studies here may not entirely reflect those of farmers field conditions.
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The paper analyzes the effects of land reform on social development poverty and land distribution-at the local level. Land reform in Colombia, understood as the allocation of public land to peasant, has granted 23 million hectares which comprises around 20% of Colombian territory and about 50% of usable productive land. Theoretically, the net impact of land reform on development is the combination of a poverty effect and a land distribution effect. Our findings suggest that land reform from 1961 onwards has slightly reduced poverty and mildly improved land distribution. Nonetheless,municipalities with strong presence of latifundia prior to1961 have experienced both a slower drop in poverty and a weaker improvement of land distribution .This paper finds that prevalence of latifundia partially offset the positive effect of land reform in promoting social development.
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This article compares the mid-nineteenth century landscape of the River Tordera delta with the present day landscape, based, above all, on the changes that have occurred in land use and land cover. The mid 19th century landscape was reconstructed using data obtained from the amillaraments (land inventories) and other historical documents. Present-day land use and cover was established through photo interpretation and field work. The most important changes detected concern the almost complete disappearance of certain crops, such as vineyards, which were very important in the 19th century; the expansion of forest in place of abandoned tilled land and the increase in built up areas, which, taken together, produce a highly fragmented landscape pattern
Resumo:
La major conscienciaci actual dels problemes de polluci que acompanyen les prdues de N del sl cap a l'atmosfera ha reorientat les investigacions cap a un coneixement ms profund dels processos implicats en les emissions dels compostos nitrogenats que comporten un major perjudici des d'un punt de vista ecolgic aix com els seus principals factors reguladors. La creixent preocupaci per l'increment de la concentraci atmosfrica de N2O s deguda a les seves interaccions amb la fotoqumica atmosfrica i el balan de radiaci de la Terra ja que interv en la destrucci de la capa estratosfrica d'oz, contribueix a l'efecte hivernacle i participa de la pluja cida. Es considera que els sls sn la principal font de N2O atmosfric. Al voltant del 90% d'aquestes emissions sn d'origen bitic; els principals processos implicats sn la desnitrificaci i la nitrificaci. L'emissi del N2O produt a travs d'aquests dos processos es caracteritza pels diferents nivells de regulaci que presenta ja que depn de la taxa dels processos, de la proporci de N canalitzada per cada procs cap a la producci de N2O i del seu consum dins el mateix sl el qual est relacionat amb les dificultats en el transport cap a l'atmosfera. Aix comporta una gran dificultat a l'hora d'aprofundir en el coneixement de les emissions de N2O del sl cap a l'atmosfera i de la seva regulaci. El desconeixement dels nivells d'emissi de N2O i de la importncia de la desnitrificaci aix com de la seva regulaci tant en sls agrcoles com naturals de les nostres contrades s el principal punt de partida dels objectius d'aquest treball.
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El Volcn Arenal es un joven estratovolcn (7ka) localizado en el noroeste de Costa Rica. Inicio su presente ciclo eruptivo el 29 de Julio de 1968 con una gran explosin lateral que mat alrededor de 90 personas. En el momento inicial de la erupcin los alrededores del volcn estaban ocupados principalmente por fincas ganaderas. Hoy da, 40 aos despus de constante actividad volcnica las tierras dedicadas a la ganadera en los alrededores del volcn han retrocedido como principal actividad econmica para dar paso a la creciente infraestructura turstica. La poblacin de La Fortuna, la ciudad ms cercana al volcn (5 km) ha crecido aceleradamente como producto del desarrollo del turismo y la cercana al volcn. Considerando los peligros volcnicos presentes, las tendencias de crecimiento de la poblacin, y la extensin de la actividad turstica, se propone una zonificacin de los usos del suelo en La Fortuna de San Carlos y alrededores del Volcn Arenal. El estudio de percepcin del riesgo en la poblacin fue implementado en La Fortuna y alrededores con posee una poblacin de aproximadamente 12000 personas. La poblacin fue dividida en dos segmentos para el anlisis. Lo primero fue una muestra (N=32) de la poblacin directamente involucrada en la actividad turstica (dueos de hotel, empleados, dueos de restaurante, operadora de tour, etc). La segunda (N=40) fue una muestra de la poblacin residente en la ciudad de La Fortuna y alrededores, relacionados o no con las actividades tursticas. Se diseo una entrevista para cada segmento investigado. As se investig la percepcin del riesgo de la poblacin directamente beneficiada por el turismo atreves de la actividad volcnica y la poblacin residente. El Volcn Arenal es visto de dos formas diferentes por la poblacin que vive en la zona de La Fortuna. Por un lado, la poblacin que vive directamente de la actividad turstica, mencionan que el volcn es la razn del acelerado crecimiento econmico en el lugar durante la ltima dcada. Adems, para este grupo el Arenal es la fuente de cientos de empleos y la fuerza que ha transformado a La Fortuna de un poblado rural a una prospera ciudad con una inusual oferta de servicios para los turistas y residentes. Por otra parte, los residentes que no dependen directamente de la actividad turstica creen que el volcn es el ms importante peligro natural en la zona, sin embargo han aprendido a convivir con l.
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Conflictes socioterritorials i participaci pblica en la gesti de l'aigua de la conca del riu Muga (Alt Empord) s un treball que incideix sobre la conflictivitat en la gesti dels rius mediterranis i prospecta en la participaci pblica -activa i vinculant- per a la resoluci de conflictes i la planificaci i gesti dels recursos hdrics. En concret, s'ha intentat donar resposta a cinc objectius: Objectius del marc teric - Comprovar l'existncia de dos discursos antagnics (radicalment oposats) en l'esfera social, cientfica i de gesti dels rius que generen conflicte i que sn insostenibles per a una gesti integral dels recursos fluvials: el discurs antropocntric i el discurs ecocntric. Matria d'estudi: L'excepcionalisme hum i l'ecologia profunda en la societat; Les disciplines de la regulaci de l'aigua i de l'ecologia fluvial en la cincia; El contracte antropocntric i el balan ecocntric en la gesti; El discurs ambiental (el riu antrpic i ecosistemtic). - Valorar si les estratgies de participaci pblica (que involucren als agents socials) gaudeixen -respecte els processos de decisi unilaterals (siguin autoritries o arbitrries)- de ms garanties per corregir i prevenir conflictes desconstructius relacionats amb l'aigua i els recursos fluvials. Matria d'estudi: Definici de conflicte en positiu; L'estratgia de cooperaci i consens en la Resoluci Alternativa de Disputes (Alternative Dispute Resolution) i 13 casos resolts de conflictes per l'aigua a l'Oest dels Estats Units; Bases d'un pla de gesti integral, adaptatiu i participatiu i el cas del San Joaquin River Management Plan (Califrnia, Estats Units). Objectius del marc prctic. Conca del riu Muga (Alt Empord) - Contextualitzar la diversificaci i intensificaci dels usos de l'aigua dins un procs de canvi dels usos del sl, particularment accelerat a partir de la dcada de 1960 i objecte de problemtiques socioterritorials d'en de la dcada de 1980. Cartografia i matriu de canvi dels usos del sl de la conca anys 1993 i 1957. Matria d'estudi: Cartografia i estadstica dels usos del sl de la conca del riu Muga (49 municipis altempordanesos, 1.050 km2), anys 1957 i 1993. Retrospectiva dels espais forestals, d'aigua, conreats i urbanitzats. - Identificar i descriure les tensions i conflictes en l's de l'aigua, aix com les caracterstiques de les solucions adoptades en el perode 1980-2000. Constatar si determinades solucions estructurals han esdevingut problemtiques a mig o llarg termini, i estimar la probabilitat de conflictes futurs. Matria d'estudi: 50 incidents problemtics en abastament d'aigua (26 tensions i 24 conflictes) i 53 mesures per fer-hi front (12 d'adaptaci de la demanda i 41 d'adaptaci de l'oferta d'aigua) entre els anys 1980 i 2000, i diferenciant dues unitats territorials de la conca (la Muga interior i la plana de la Muga). - Caracteritzar quins sn els temes en matria d'aigua que no disposen de consens entre els agents socioeconmics, tcnics i poltics locals reunits en les sessions de discussi del projecte MUGA. Determinar si les estratgies participatives poden prosperar perqu sn factibles i idnies. Matria d'estudi: Projecte MUGA: Gestin del recurso agua con participacin de agentes. Estudio para la cuenca del ro Muga (Girona), 2000-2003 - UAB i UdG; La dissensi d'opinions dels 30 participants a les 4 sessions de discussi entorn l's i gesti de l'aigua de la conca de la Muga; 6 temes de conflicte, 14 subtemes i 31 punts de discussi, 9 dels quals punts calents de conflicte (destructius i indicadors de punts de disfunci en la gesti de l'aigua de la conca).
Resumo:
En la tesi es presenta una anlisi de l'evoluci dels canvis succets en el paisatge costaner de la Costa Brava (22 municipis litorals) en els darrers cinquanta anys (1956-2003); un estudi de la seva estructura ecopaisatgstica, actual i passada, amb una especial mfasi en la diagnosi de les conseqncies geoambientals de l'esclat urbanstic iniciat a la dcada de 1960, i s'ha determinat quina ha estat la tendncia de canvi en els darrers vint-i-cinc anys la qual s'ha utilitzat per a elaborar models explicatius de la dinmica territorial seguida i projectar-los cap al futur tot dissenyant escenaris probables. A les Bases teriques s'exposa en quina parcella del coneixement cientfic es situa aquesta recerca i es repassa l'evoluci dels diferents corrents i enfocaments que han precedit, dins la Cincia Geogrfica, els estudis sobre transformaci del paisatge. Es posa especial en els principis i metodologies que plantegen les dues escoles d'anlisi del paisatge en que es basa aquesta tesi: la Landscape Ecology i la estructurada a l'entorn del programa internacional Land Use and Land Cover Change (LUCC). S'ha dissenyat una pauta metodolgica per a l'anlisi paisatgstica d'un territori a diferents escales: des de l'mbit regional de tota la Costa Brava (66.230 ha), on es poden detectar les tendncies generals, fins l'estudi detallat a escala local, on s'ha pres com a rea d'estudi tres municipis del centre de la Costa Brava (6.960 Ha): Palams, Calonge i Castell-Platja d'Aro. Els principals resultats obtinguts sn els segents: Una cartografia d'usos i cobertes del sl de tres perodes temporals i la conseqent interpretaci espacial per a cada etapa: 1957 (situaci preturstica), 1980 (inici de les actuacions dels ajuntaments democrtics) i 2003 (actualitat). Una anlisi quantitativa de la transformaci del paisatge i de les relacions espacials associades al canvi, a partir de la cartografia d'usos i cobertes del sl dels tres perodes mapificats (1956, 1980, 2003). Amb l'objectiu d'arribar a definir quina ha estat la dinmica dels canvis ocorreguts al llarg dels darrers gaireb cinquanta anys. Una anlisi de l'estructura del mosaic paisatgstic de cadascun dels talls temporals per mitj de l'aplicaci dels principals ndexs de l'Ecologia del Paisatge. S'ha analitzat la geometria de la conversi dels usos del sl i s'han posat de manifest les repercussions ecolgiques i paisatgstiques d'aquests canvis. Per una banda, a partir del clcul i interpretaci dels ndexos esmentats s'ha analitzat l'evoluci de la morfologia i la distribuci territorial dels quatre principals usos i cobertes del sl de la Costa Brava. Per l'altra, per a la Costa Brava centre s'ha analitzat l'estat dels dos sistemes naturals del litoral amb ms pressi antrpica: la franja estrictament costanera i les masses forestals. Respecte als tres municipis de la Costa Brava centre s'han tingut en compte en l'anlisi de l'evoluci del paisatge a escala local, les actuacions desenvolupades en l'mbit urbanstic municipal i les seves conseqncies paisatgstiques i ambientals. A partir de la informaci ja processada, s'han detectat les tendncies de canvi a partir de models de canvi d'usos i cobertes del sl. S'han incorporat tamb els factors biofsics i antrpics, socials i econmics, condicionants i responsables d'una determinada utilitzaci del territori en cadascun dels tres perodes. Mitjanant l'anlisi multivariable s'ha intentat descobrir el conjunt de factors que influencien en la taxa i el patr espacial de canvi d'usos i les seves conseqncies territorials. Finalment s'ha aplicat un model de simulaci, basat en els automatismes cellulars de Markov, per tal de projectar les tendncies de canvi i plantejar escenaris futurs, una eina bsica per a la planificaci futura del territori i per al control de les problemtiques ambientals. Aquestes mesures serveixen per a definir, per a la Costa Brava centre, un patr espacial dels canvis d'usos del sl a nivell local, i, per al conjunt de la Costa Brava, per a predir, mitjanant models de simulaci quantitativa, els possibles desenvolupaments i per estimar els impactes.
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Introduo: O adiamento das altas clnicas nas Unidades de Cuidados Continuados Integrados (UCCI) por motivos sociais actualmente considerado um dos principais motivos que impedem a integrao atempada de novos clientes na Rede Nacional de Cuidados Continuados, RNCC, daqui em diante designada como a REDE. Este atraso tem impacto ao nvel da recuperao e estabilizao dos utentes, bem como ao nvel de eficincia e eficcia da UCCI, no podendo deixar de se considerarem os aspectos sociais e econmicos. Objectivo Geral: Identificar os determinantes que influenciam as altas clnicas em UCCI. Mtodos e Populao do Estudo: Este um estudo de caso colectivo, em que os dados observacionais, transversais, so recolhidos por meio de questionrio de auto-relato (por cada rea de interveno directa) e por anlise dos processos de consulta de pacientes. O objecto desta pesquisa abrange dois grupos: o grupo de amostra composto por 70 profissionais de sade que lidam directamente com os utentes e o grupo amostra composto de utentes internados na UCCI L Nostrum, com alta clnica entre 1/1/2011 e 31/12/2012, e que foram integrados atravs da REDE. Foram recolhidos os dados de 293 utentes sendo objecto de estudo os casos de 83 utentes integrados atravs da REDE e com prolongamento de internamento por motivos sociais. Resultados: Na percepo dos profissionais de sade, as respostas institucionais apresentam-se como a condicionante mais indicada, tanto para os utentes em geral, com 22 indicaes (88%) como para os utentes da REDE, com 10 indicaes (40%). Relativamente aos motivos familiares h referncia de 76% para os utentes em geral e de 36% para os utentes da REDE. Os motivos econmicos tambm apresentam, para os profissionais inquiridos, um valor expressivo (68%) nos utentes em geral, estando nos da REDE este factor condicionante a par com os motivos familiares (36%). Os motivos estruturais tm menor expresso tanto nos utentes em geral (32%) como nos utentes da REDE (16%). Outros para os utentes em geral, refere-se a dependncia funcional (4%). Nos motivos familiares, para os utentes em geral, 23 (92%) foi mais vezes indicada a insuficincia de suporte familiar, para os utentes da REDE, 13 (52%). A ausncia de suporte familiar, para os utentes em geral, representa 48% das respostas, seguindo-se o suporte inadequado (28%) e a ausncia de cuidadores (24%). Para os utentes da REDE, o suporte inadequado apresenta-se como segundo motivo (7%), seguindo-se a ausncia de suporte familiar (16%). Na percepo dos profissionais, os utentes da REDE esto tambm condicionados pela distncia geogrfica (8%) da sua rea residencial. Em termos estruturais, os motivos mais assinalados pelos profissionais para a generalidade dos utentes foram as barreiras fsicas mobilidade (80%) e a habitao sem condies bsicas de habitabilidade (78%). Os mesmos motivos foram assinalados para os utentes da REDE, barreiras fsicas mobilidade (40%) e habitao sem condies de habitabilidade (28%). No entanto, relativamente aos utentes em geral, a ausncia de habitao (29%) e a distncia geogrfica (4%) tambm foram motivos assinalados. Dos motivos econmicos percebidos pelos profissionais, a insuficincia de rendimentos o factor mais assinalado pela generalidade dos utentes (84%) e pelos da REDE (68%), seguida da percepo da capacidade de reposta limitada das instituies, 64% para a generalidade dos utentes e 28% para os da REDE e por fim os tipos de respostas insuficientes para as necessidades individuais dos utentes (20% dos utentes em geral e 12% da REDE). No total dos dois anos, 2011 e 2012, verificaram-se na UCCI L Nostrum 293 prorrogaes (100%) das quais 210 (71,6%) foram consideradas dentro do prazo e justificadas com motivos clnicos, enquanto 83 (28,3%) foram efectivamente protelamentos por motivos sociais, tendo em conta que nestes casos os utentes j no tinham critrios clnicos que justificassem a sua permanncia na UCCI. Das 210 prorrogaes consideradas dentro do prazo e justificadas com motivos clnicos, 93 (44,3%) foram-no por tempo de espera para transferncia de UCCI. Em 2011, dos 146 utentes com alta protelada (100%), 50 utentes (34,2%) permaneceram na UCCI por motivos sociais, enquanto em 2012 houve registo de 33 casos de protelamento (22,4%) em 147 (100%) altas prorrogadas. Concluses: Dos factores identificados como motivo de protelamento nos 83 utentes, estritamente por motivos sociais, destaca-se o protelamento de alta por espera de integrao em equipamento/resposta adequada, nomeadamente lar ou servios de apoio domicilirio (79,5%), seguindo-se a insuficincia de rendimentos do utente/familiares para contratao de servios ou resposta institucional (74,7%), a inexistncia de condies habitacionais para regresso ao domiclio (63,9%) e a insuficincia de suporte familiar (54,2%). Regista-se tambm a inadequao do suporte familiar (31,3%), a inexistncia de suporte familiar (28,9%) e, em menor percentagem, a ausncia de condies estruturais (13,3%). A ausncia de domiclio (sem abrigo) (8,4%) e a ausncia de rendimentos (4,8%) tambm foram factores inibidores da alta clnica. Dos 293 utentes identificados que tiveram protelamento da alta por motivos sociais verificou-se que 144 (49,1%) dos utentes permaneceram unicamente pela existncia de condicionantes institucionais e familiares/estruturais. Aspectos ticos: ao longo deste estudo, foram assegurados e respeitados, todos os procedimentos de garantia da confidencialidade e rigor na recolha dos dados, e a no interferncia nas dinmicas da instituio, dos utentes e dos profissionais.
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ATSR-2 active fire data from 1996 to 2000, TRMM VIRS fire counts from 1998 to 2000 and burn scars derived from SPOT VEGETATION ( the Global Burnt Area 2000 product) were mapped for Peru and Bolivia to analyse the spatial distribution of burning and its intra- and inter-annual variability. The fire season in the region mainly occurs between May and October; though some variation was found between the six broad habitat types analysed: desert, grassland, savanna, dry forest, moist forest and yungas (the forested valleys on the eastern slope of the Andes). Increased levels of burning were generally recorded in ATSR-2 and TRMM VIRS fire data in response to the 1997/1998 El Nino, but in some areas the El Nino effect was masked by the more marked influences of socio-economic change on land use and land cover. There were differences between the three global datasets: ATSR-2 under-recorded fires in ecosystems with low net primary productivities. This was because fires are set during the day in this region and, when fuel loads are low, burn out before the ATSR-2 overpass in the region which is between 02.45 h and 03.30 h. TRMM VIRS was able to detect these fires because its overpasses cover the entire diurnal range on a monthly basis. The GBA2000 product has significant errors of commission (particularly areas of shadow in the well-dissected eastern Andes) and omission (in the agricultural zone around Santa Cruz, Bolivia and in north-west Peru). Particular attention was paid to biomass burning in high-altitude grasslands, where fire is an important pastoral management technique. Fires and burn scars from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) data for a range of years between 1987 and 2000 were mapped for areas around Parque Nacional Rio Abiseo (Peru) and Parque Nacional Carrasco (Bolivia). Burn scars mapped in the grasslands of these two areas indicate far more burning had taken place than either the fires or the burn scars derived from global datasets. Mean scar sizes are smaller and have a smaller range in size between years the in the study area in Peru (6.6-7.1 ha) than Bolivia (16.9-162.5 ha). Trends in biomass burning in the two highland areas can be explained in terms of the changing socio-economic environments and impacts of conservation. The mismatch between the spatial scale of biomass burning in the high-altitude grasslands and the sensors used to derive global fire products means that an entire component of the fire regime in the region studied is omitted, despite its importance in the farming systems on the Andes.
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Many lowland rivers across northwest Europe exhibit broadly similar behavioural responses to glacial-interglacial transitions and landscape development. Difficulties exist in assessing these, largely because the evidence from many rivers remains limited and fragmentary. Here we address this issue in the context of the river Kennet, a tributary of the Thames, since c. 13,000 cal BP. Some similarities with other rivers are present, suggesting that regional climatic shifts are important controls. The Kennet differs from the regional pattern in a number of ways. The rate of response to sudden climatic change, particularly at the start of the Holocene and also mid-Holocene forest clearance, appears very high. This may reflect abrupt shifts between two catchment scale hydrological states arising from contemporary climates, land use change and geology. Stadial hydrology is dominated by nival regimes, with limited winter infiltration and high spring and summer runoff. Under an interglacial climate, infiltration is more significant. The probable absence of permafrost in the catchment means that a lag between the two states due to its gradual decay is unlikely. Palaeoecology, supported by radiocarbon dates, suggests that, at the very start of the Holocene, a dramatic episode of fine sediment deposition across most of the valley floor occurred, lasting 500-1000 years. A phase of peat accumulation followed as mineral sediment supply declined. A further shift led to tufa deposition, initially in small pools, then across the whole floodplain area, with the river flowing through channels cut in tufa and experiencing repeated avulsion. Major floods, leaving large gravel bars that still form positive relief features on the floodplain, followed mid-Holocene floodplain stability. Prehistoric deforestation is likely to be the cause of this flooding, inducing a major environmental shift with significantly increased surface runoff. Since the Bronze Age, predominantly fine sediments were deposited along the valley with apparently stable channels and vertical floodplain accretion associated with soil erosion and less catastrophic flooding. The Kennet demonstrates that, while a general pattern of river behaviour over time, within a region, may be identifiable, individual rivers are likely to diverge from this. Consequently, it is essential to understand catchment controls, particularly the relative significance of surface and subsurface hydrology. (c) 2005 Elsevier B.V. All rights reserved.
Resumo:
Under the United Nations Framework Convention on Climate Change (UNFCCC), Non-Annex 1 countries such as Kenya are obliged to report green house gas (GHG) emissions from all sources where possible, including those from soils as a result of changes in land use or land management. At present, the convention encourages countries to estimate emissions using the most advanced methods possible, given the country circumstances and resources. Estimates of soil organic carbon (SOC) stocks and changes were made for Kenya using the Global Environment Facility Soil Organic Carbon (GEFSOC) Modelling System. The tool conducts analysis using three methods: (1) the Century general ecosystem model; (2) the RothC soil C decomposition model; and (3) the Intergovernmental Panel on Climate Change (IPCC) method for assessing soil C at regional scales. The required datasets included: land use history, monthly mean precipitation, monthly mean minimum and maximum temperatures for all the agro-climatic zones of Kenya and historical vegetation cover. Soil C stocks of 1.4-2.0 Pg (0-20 cm), compared well with a Soil and Terrain (SOTER) based approach that estimated similar to .8-2.0 Pg (0-30 cm). In 1990 48% of the country had SOC stocks of < 18 t C ha(-1) and 20% of the country had SOC stocks of 18-30 t C ha(-1), whereas in 2000 56% of the country had SOC stocks of < 18 t C ha(-1) and 31% of the country had SOC stocks of 18-30 t C ha(-1). Conversion of natural vegetation to annual crops led to the greatest soil C losses. Simulations suggest that soil C losses remain substantial throughout the modelling period of 1990-2030. All three methods involved in the GEFSOC System estimated that there would be a net loss of soil C between 2000 and 2030 in Kenya. The decline was more marked with RothC than with Century or the IPCC method. In non-hydric soils the SOC change rates were more pronounced in high sandy soils compared to high clay soils in most land use systems. (C) 2007 Elsevier B.V. All rights reserved.
Resumo:
Rural land managers need access to sound advice and information to respond to pressures from environmental regulations, declining farm incomes, changing patterns in international trade and new institutional arrangements within the domestic food chain. Governments have cut back their provision of advisory services but need more than ever to influence land managers' decisions to achieve a growing array of policy objectives: The paper develops a conceptual framework for analysing advisory services and concludes, through a review of sixteen case studies, that the needs of both governments and land managers can be met by a diverse mixture of private and public sector provision. (C) 2003 Elsevier Ltd. All rights reserved.
Resumo:
In many river floodplains in the UK, there has been a long history of flood defence, land reclamation and water regime management for farming. In recent years, however, changing European and national policies with respect to farming, environment and flood management are encouraging a re-appraisal of land use in rural areas. In particular, there is scope to develop, through the use of appropriate promotional mechanisms, washland areas, which will simultaneously accommodate winter inundation, support extensive farming methods, deliver environmental benefits, and do this in a way which can underpin the rural economy. This paper explores the likely economic impacts of the development of flood storage and washland creation. In doing so, consideration is given to feasibility of this type of development, the environmental implications for a variety of habitats and species, and the financial and institutional mechanisms required to achieve implementation. (C) 2007 Elsevier Ltd. All rights reserved.
Resumo:
Natural resource-dependent societies in developing countries are facing increased pressures linked to global climate change. While social-ecological systems evolve to accommodate variability, there is growing evidence that changes in drought, storm and flood extremes are increasing exposure of currently vulnerable populations. In many countries in Africa, these pressures are compounded by disruption to institutions and variability in livelihoods and income. The interactions of both rapid and slow onset livelihood disturbance contribute to enduring poverty and slow processes of rural livelihood renewal across a complex landscape. We explore cross-scale dynamics in coping and adaptation response, drawing on qualitative data from a case study in Mozambique. The research characterises the engagements across multiple institutional scales and the types of agents involved, providing insight into emergent conditions for adaptation to climate change in rural economies, The analysis explores local responses to climate shocks, food security and poverty reduction, through informal institutions, forms of livelihood diversification and collective land-use systems that allow reciprocity, flexibility and the ability to buffer shocks. However, the analysis shows that agricultural initiatives have helped to facilitate effective livelihood renewal, through the reorganisation of social institutions and opportunities for communication, innovation and micro-credit. Although there are challenges to mainstreaming adaptation at different scales, this research shows why it is critical to assess how policies can protect conditions for emergence of livelihood transformation. (C) 2008 Elsevier Ltd. All rights reserved.
