Influencia del cambio de uso del suelo sobre las reservas de carbono orgánico en el Parque Natural Regional Cortadera, Boyacá (Colombia)

Los páramos almacenan grandes reservas de carbono orgánico en el suelo (COS), influenciados por las condiciones climáticas y biogeoquímicas, propias del ecosistema; sin embargo, su progresiva conversión hacia cultivos, ganadería o minería incide directamente en las reservas de COS. Con el fin de determinar el efecto que ejerce el cambio de uso de suelo sobre la variabilidad de las reservas de COS, se realizó un monitoreo de COS entre 2013, 2018 y 2020, en el Parque Natural Regional Cortadera. Se estudiaron parcelas permanentes de muestreo (PPM), ubicadas bajo tres diferentes usos del suelo: conservado, en recuperación e intervenido. Se analizaron muestras de carbono orgánico y densidad aparente, a dos profundidades (0-15 cm y 15-30 cm). Se encontró que la PPM en escenario conservado presentó los contenidos más altos de COS, con valores de 290,37; 199,22 y 257,5 tC ha-1, para cada uno de los años en estudio; seguido por la PPM en recuperación, que evidenció valores de COS 215,3 tC ha-1, en el 2020, en contraste con la PPM intervenida, que presentó contenidos mínimos de 15,50; 34,01 y 88,06 tC ha-1. Se observó que los mayores contenidos de COS se encuentran a la profundidad de 15 a 30 cm. Dichos aspectos, resaltan la importancia de avanzar en acciones enfocadas a la protección de ecosistemas estratégicos, considerando las constantes amenazas relacionadas con la transformación del paisaje y, con ello, la posibilidad de proveer funciones y servicios asociados a la captura de carbono y la regulación climática.

The paramos accumulate high stocks of soil organic carbon (SOC), influenced by the climatic and biogeochemical conditions of the ecosystem. However, their progressive conversion to crops, livestock, or mining has a direct impact on the SOC stocks. To determine the effect of land use change on the variability of SOC stocks, monitoring of SOC content was conducted between the years 2013, 2018, and 2020 in the Parque Natural Regional Cortadera. Permanent sampling plots (PPS) located under three different land uses were studied: conserved, recovering, and intervened. To do so, samples of soil organic carbon and bulk density at two depths were analyzed (0-15 cm and 15-30 cm). The conserved PPS showed the highest SOC contents, with maximum values of 290.37; 199.22, and 257.5 tC ha-1 for each of the years under study; follow by the recovery PPM that presented COS values of 215.3 tC ha-1 in 2020, in contrast to the intervened PSP that showed minimum contents of 15.50; 34.01 and 88.06 tC ha-1. Furthermore, the highest SOC contents were found at 15-30 cm depth. These factors emphasize the importance of carrying out actions focused on protecting strategic ecosystems such as paramos, taking into account the continuous threats related to the transformation of the landscape and, consequently, the possibility of providing ecosystem functions and services related to carbon capture and climate regulation.

Mariposas frugívoras (Lepidoptera: Nymphalidae) en plantaciones de eucalipto y bosques de galería en la Orinoquia colombiana / Fruit-feeding butterflies (Lepidoptera: Nymphalidae) in eucalyptus plantations and gallery forests in the Colombian Orinoquia

Introducción: Una actividad económica que ha tenido auge en la última década en la altillanura es la forestación de sabanas con alteraciones antrópicas, pero se desconoce su papel en la conservación de las mariposas frugívoras de los bosques de galería dentro de los núcleos forestales. Objetivo: Comparar la diversidad de mariposas frugívoras en plantaciones de eucalipto y bosques de galería, y el papel de las variables ambientales. Métodos: Utilizamos trampas Van Someren-Rydon, dos réplicas de cuatro trampas, en cada uno de los cuatro hábitats muestreados simultáneamente desde diciembre 2020 hasta julio 2021: plantación de eucaliptos de cuatro años; plantación de eucaliptos de seis años; bosque de galería de suelo seco y bosque de galería anegado. También registramos diez variables abióticas, estructurales, alimentarias y de hábitat. Resultados: Recolectamos 227 especímenes de mariposas frugívoras (30 especies, 23 géneros y 5 subfamilias de la familia Nymphalidae). Había más especies en los bosques. Las especies de mariposas variaron más del 50 % entre los hábitats; Satyrinae fue más diversa en las plantaciones. Conclusión: La forestación en esta área proporciona hábitats para algunas especies de mariposas frugívoras de los remanentes de bosques naturales adyacentes. Las forestaciones representan un escenario de alteración intermedia entre las dos unidades de paisaje dominantes en la región.

Introduction: An economic activity that has boomed in the last decade in Colombian highlands is the afforestation of anthropized savannas, but its role in the conservation of fruit-feeding butterflies of gallery forests within forest cores is unknown. Objective: To compare the diversity of fruit-feeding butterflies in eucalyptus plantations and gallery forests, and the role of environmental variables. Methods: We used Van Someren-Rydon traps, two replicates of four traps, on each of four habitats sampled simultaneously from December 2020 to July 2021: four-years-old eucalyptus plantation; six-years-old eucalyptus plantation; dry soil gallery forest and waterlogged gallery forest. We also recorded ten abiotic, structural, food and habitat variables. Results: We collected 227 specimens of fruit-feeding butterflies (30 species, 23 genera, and 5 subfamilies within the family Nymphalidae). There were more species in the forests. The butterfly species varied over 50 % between the habitats; Satyrinae were more diverse in plantations. Conclusion: Afforestation in this area provides habitats for some species of fruit-feeding butterflies from adjacent natural forest remnants. Afforestations represent an intermediate disturbance scenario between the two dominant landscape units in the region.

Size distribution and sex ratio between populations of the artisanal harvested land crab Cardisoma guanhumi (Decapoda: Gecarcinidae), with the estimation of relative growth and size at sexual maturity in Puerto Rico / Distribución de tallas y proporción de sexos entre poblaciones del cangrejo de tierra cosechado artesanalmente Cardisoma guanhumi (Decapoda: Gecarcinidae), con la estimación del crecimiento relativo y tamaño en la madurez sexual en Puerto Rico

Abstract Introduction: Knowledge of growth patterns, sex ratio, and sexual maturity are of importance to exploited populations. The land crab Cardisoma guanhumi is an artisanal and subsistence exploited species in Puerto Rico. However, the growth patterns and sexual maturity of the local populations are not known. Objectives: This study has a double objective: (1) to compare the size and sex structure between populations and (2) to model the relative growth of structures related to reproduction to estimate the average size of morphometric sexual maturity (MSM) for both males and females. Methods: A total of 2 849 specimens were captured from nine dispersed populations on the island between 2001 and 2020. Carapace width (CW) was measured as an estimator of the absolute size of all individuals, together with the propodus length (PL) in males and the abdomen width in females (AW). Differences in length structure between sexes and populations were tested by applying goodness-of-fit tests based on Kernel Density Estimators (KDE). The relative growth pattern was modeled adjusting a spline from which the maximum of its second derivative was calculated as an estimator of the MSM, and bootstrapping was used to generate confidence intervals. Results: Differences were found in size structures, between sexes, and between sites. Our estimates of morphometric sexual maturity resulted in a sexual maturity size for males between 57.9 and 79.0 mm CW, while in females, morphological maturity occurs between 43.8 to 51.5 mm CW. Conclusions: We found inter-population differences in body size that can be attributed to differences in the history of changes of land use and the exploitation biased towards larger individuals, though differences in recruitment should also be considered. Current regulations in Puerto Rico protect female crabs but not to larger male crabs. The regulation establishes that crabs smaller than 64 mm carapace width cannot be captured, leaving immature male crabs over 64 mm CW unprotected. We suggest considering different size limits depending on the sex of the crab. This will allow the full range of sizes where sexual maturity is reached to be protected, increasing the likelihood of the population's size to increase.

Resumen Introducción: El conocimiento de los patrones de crecimiento, la proporción de sexos y la madurez sexual son de suma importancia para las poblaciones explotadas. El cangrejo terrestre Cardisoma guanhumi es una especie explotada artesanalmente y para subsistencia en Puerto Rico. Sin embargo, se desconocen los patrones de crecimiento y la madurez sexual para la isla. Objetivos: Este estudio tiene un doble objetivo: (1) comparar el tamaño y la estructura sexual entre las poblaciones y (2) modelar el crecimiento relativo de estructuras relacionadas con la reproducción (propodo en machos y abdomen en hembras) para estimar el tamaño promedio de madurez sexual morfométrica (MSM). Métodos: Se capturaron un total de 2 849 especímenes de nueve poblaciones dispersas en la isla, entre 2001 y 2020. Se midió el ancho del caparazón (AC) como un estimador del tamaño absoluto de todos los individuos, junto con el largo de propodo en los machos y el ancho del abdomen en las hembras. Las diferencias en la estructura de tallas entre sexos y poblaciones se probaron aplicando la prueba de bondad de ajuste basado en estimaciones de densidad kernel (KDE). El patrón de crecimiento relativo se modeló ajustando un spline a partir del cual se calculó el máximo de su segunda derivada como estimador del MSM y se utilizó bootstrapping para generar intervalos de confianza. Resultados: Se encontraron diferencias en las estructuras de tallas, entre sexos y poblaciones. Nuestras estimaciones de madurez sexual morfométrica dieron como resultado un tamaño de madurez sexual para los machos entre 57.9 y 79.0 mm AC, mientras que, en las hembras, la madurez morfométrica se produce entre 43.8 y 51.5 mm AC. Conclusiones: La diferencia en el tamaño de la población se puede atribuir a las diferencias entre poblaciones en el cambio de uso de la tierra y la presión de explotación asociada con el sesgo hacia la captura de individuos más grandes o el reclutamiento. Las regulaciones actuales en Puerto Rico brindan protección a las hembras, pero no a los machos más grandes. El reglamento establece que no se pueden capturar cangrejos de menos de 64 mm de AC dejando desprotegidos los cangrejos machos inmaduros de más de 64 mm AC. Sugerimos considerar diferentes límites de tamaño según el sexo del cangrejo. Esto permitirá proteger un rango más amplio de tamaños donde se alcanza la madurez sexual, aumentando la probabilidad de un incremento en el tamaño de la población.

Will global change modify the distribution of the Anadenanthera colubrina (Fabales: Fabaceae) plant, a key species in dry tropical forest?

Introduction: Seasonally dry tropical forests (SDTF) are one of the most threatened terrestrial ecosystems on the planet as a consequence of global change. They harbor high biodiversity and provide a wide range of ecosystem services; therefore, their conservation is a priority worldwide. Climate warming, as well as land use patterns, are leading to species distribution range shifts. Objective: The objective of this work was to study the current and future potential distribution of a SDTF representative tree species (Anadenanthera colubrina) in the Argentinian Sub Andean Piedmont nucleus and to assess the effects of land use and climate changes. Methods: Current and future potential distribution was modeled with Maxent, using 49 presence points and 20 variables. Climate change effects were estimated in four different temperature and carbon dioxide concentration scenarios. Land use changes were determined subtracting the deforested area until 2017 to the current and future potential distribution of the species. Results: A. colubrina current distribution represents 18 % of Northwestern Argentina. Land use changes decreased almost 25 % of it and climate change will probably cause a retraction in the East and a slight expansion towards the West and South of the current distribution. The synergistic effect of land use and climate change projected to the worst scenario would reduce 63 % of its current distribution. Conclusions: Our data demonstrate the central role of distribution range studies to assess the effects of anthropic activities. Climate change and land use change would have a negative and synergistic effect on the distribution of A. colubrina. Although a possible expansion of the Sub Andean Piedmont nucleus of SDTF would occur, this expansion may be limited by the Sub Andean mountain range that could act as an orographic barrier.

Introducción: Los Bosques Tropicales Estacionalmente Secos (BTES) son unos de los ecosistemas terrestres más amenazados del planeta como consecuencia del cambio global. Estos bosques albergan una alta biodiversidad y proporcionan una amplia gama de servicios ecosistémicos, por lo que su conservación es una prioridad a nivel mundial. El cambio climático y el cambio en los usos del suelo están afectando la distribución de las especies. Objetivo: El objetivo de este trabajo fue estudiar la distribución potencial de una especie representativa de BTES (Anadenanthera colubrina) en el núcleo del Piedemonte subandino argentino y evaluar los efectos del cambio en los usos del suelo y del cambio climático sobre su distribución. Métodos: La distribución actual y futura de A. colubrina fue modelada con Maxent, utilizando 49 puntos de presencia y 20 variables. Los efectos del cambio climático se estimaron en cuatro escenarios que difieren en los niveles de temperatura y concentración de dióxido de carbono. Los efectos del cambio en el uso del suelo se estimaron descontando el área deforestada hasta el 2017 a la distribución actual y futura de la especie. Resultados: La distribución actual de A. colubrina representa un 18 % del Noroeste Argentino. Los cambios en el uso del suelo produjeron una disminución del 25 % del área de distribución actual y el cambio climático probablemente causará una retracción al Este y una expansión hacia el oeste y sur de su distribución. El efecto sinérgico del cambio en el uso del suelo y el cambio climático podría producir una pérdida del 63 % considerando el peor escenario de cambio climático. Conclusiones: Nuestros datos demuestran el rol fundamental de los estudios de distribución para evaluar los efectos de las actividades antrópicas. Los cambios en los usos del suelo y el cambio climático podrían tener un efecto negativo y sinérgico sobre la distribución de A. colubrina. La posible expansión del núcleo Piedemonte de SDTF hacia el oeste y el sur de la región no estaría limitada por cambios en el uso del suelo, aunque las cadenas montañosas podrían actuar como barreras orográficas y limitar la expansión.

Insights for policy-based conservation strategies for the Rio de la Plata Grasslands through the IPBES framework / Insights para estratégias de conservação baseadas em políticas para as pradarias do Rio da Prata através da estrutura do IPBES

Abstract The Río de la Plata Grasslands (RPG) are one of the most modified biomes in the world. Changes in land use and cover affect the RPG's rich biodiversity. In particular, the expansion of crops, overgrazing, afforestation, and the introduction of exotic species pose a major threat to the conservation of biodiversity and ecosystem services (BES). In this study, we applied the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) conceptual framework as a new lens to approach biodiversity conservation enactments in the RPG. First, we systematically reviewed published scientific literature to identify direct and indirect drivers that affect the RPG's BES. Further, we conducted an extensive analysis of management policies affecting the BES directly in the region, at a national and international level. We conclude by offering recommendations for policy and praxis under the umbrella of the IPBES framework.

Resumo As pradarias do Rio da Prata são um dos biomas mais modificados no mundo. Alterações nos usos do solo afetam a rica biodiversidade deste ecossistema. A expansão da agricultura, sobrepastoreio, arborização e a introdução de espécies exóticas, principalmente, representam uma grande ameaça para a conservação da biodiversidade e dos serviços ecossistêmicos (BES). Neste estudo, aplicamos a estrutura conceptual da Plataforma Intergovernamental sobre Biodiversidade e Serviços Ecossistêmicos (IPBES) como uma nova forma de abordar as políticas de conservação da biodiversidade neste bioma. Primeiro, revisamos sistematicamente artigos científicos publicados de forma a identificar fatores diretos e indiretos que afetam os BES nas pradarias do Rio da Prata. Adicionalmente, realizamos uma extensa análise das políticas de gestão que afetam diretamente os BES na região, quer a nível nacional, quer internacional. Concluímos com propostas e recomendações de políticas e práticas sob a égide do quadro do IPBES.

Colémbolos epiedáficos (Hexapoda: Collembola) en dos usos del suelo en la Altillanura colombiana

Introducción: Los colémbolos epiedáficos participan en una amplia variedad de servicios ecosistémicos relacionados con la disponibilidad de nutrientes para las plantas, el almacenamiento y la regulación del agua, la estabilidad del suelo y el control de la humedad y el pH necesarios para la fertilidad de los suelos. Por esta razón, los colémbolos epiedáficos se consideran como organismos sensibles a los cambios generados en el uso del suelo. Objetivo: Comparar la fauna epiedáfica de dos tipos de vegetación introducida: pastos y plantaciones de Eucalyptus pellita en una región de los Llanos Orientales de Colombia. Métodos: La recolección de los colémbolos se realizó en áreas con cobertura de pastos introducidos y áreas forestadas de diferentes edades, con trampas pitfall que contenían Propilenglicol al 40 % como preservante; durante la época seca y la época húmeda. Se comparó la riqueza efectiva de géneros y se explicó su composición en función de 14 variables ambientales y dasométricas mediante un análisis de redundancia (RDA). Resultados: La colembofauna estuvo compuesta por Entomobryomorpha (62 %), Poduromorpha (17 %) y Symphypleona (21.1 %) representados en 12 familias y 26 géneros. La riqueza efectiva de géneros fue significativamente mayor en los pastos que en las plantaciones de E. pellita, pero la abundancia no disminuye significativamente, con excepción de las plantaciones jóvenes durante la época seca. El ensamblaje de colémbolos observados en el área se relacionó principalmente con el desarrollo de cobertura forestal, la disponibilidad de materia orgánica alrededor de la trampa y el contenido de Nitrógeno en el suelo. Conclusiones: Las áreas forestadas permitieron un ensamblaje de colémbolos, menos diverso que las pasturas, pero compuesto tanto por especies adaptadas a áreas abiertas, como de las áreas naturales boscosas circundantes.

Introduction: Epiedaphic springtails participate in a wide variety of services linked to plant nutrient availability, water storage and regulation, soil stability and control of moisture and pH necessary for soil fertility. Therefore, epiedaphic springtails are sensitive to soil use change. Objective: To compare diversity of epiedaphic springtails in two types of introduced vegetation: pastures and forestations of Eucalyptus pellita in a region of the Colombian eastern plans. Methods: Springtails were collected from introduced pastures and young, middle and mature forested areas of E. pellita, using pitfall traps containing Propylene Glycol (40 %) as preservative, during one dry and one wet season. Alfa and Beta diversity were compared at genus level, and community composition was explained using a set of 14 environmental variables through a redundancy analysis (RDA). Results: Epiedaphic springtails were represented by Entomobryomorpha (62 %), Poduromorpha (17 %) and Symphypleona (21.1 %), 12 families and 26 genera. Effective number of Collembola genera was lower in plantations but abundance was different only in young plantations during dry season. The variables related to forest coverage, soil organic matter coverage and Nitrogen better explained the observed genera assemblage. Conclusions: Forest plantations allowed an assembly of springtails less diverse than in pastures; but comprised both types of genera, those proper of open areas and those from surrounding natural wooded areas.

Cálculo de emissões de CO2 provenientes da mudança do uso da terra para produção de soja no estado do Rio Grande do Sul / Calculation of CO2 emission derived from land-use change from soybean production at Rio Grande do Sul state, Brazil

RESUMO Atualmente um dos impactos ambientais de maior preocupação, as emissões de gases de efeito estufa (GEE) influenciam as tomadas de decisão provenientes tanto do setor privado como do governamental. Nessa preocupação, encontra-se o processo de crescimento da produção de biodiesel de soja que ocorre no Brasil, e no Rio Grande do Sul, um dos principais produtores dessa matéria-prima. Baseado nisso, a quantificação das emissões de GEE da cultura da soja e seus prováveis impactos passam pela realização de um inventário que contemple a aproximação maior para a realidade dessa região. Assim, neste trabalho, as emissões de GEE provenientes da mudança do uso da terra (MUT) para produção de soja foram investigadas considerando dados históricos de 20 anos da produção da cultura no Rio Grande do Sul (entre 1992 e 2013). Nesta pesquisa, verificou-se o crescimento da cultura predominantemente sobre lavouras temporárias, o que repercute em uma quantificação diferente do que é apresentada nos inventários atuais, em que é apresentado um avanço da soja sobre florestas. Neste caso, o trabalho em questão verificou que, conforme metodologia do Painel Intergovernamental sobre Mudança do Clima (IPCC), a MUT ocorreu somente em 15,4% da área em que a soja avançou. Não menos importante, o trabalho sugere discussões futuras para metodologias que contemplem o avanço da soja sobre áreas de várzea, conforme evidenciado neste estudo.

ABSTRACT One of the environmental impacts that presents great concern nowadays, the green-house gases (GHG) emissions affect decision-making from both government and private sector. Within this concern is the soybean biodiesel production growing that takes place in Brazil and Rio Grande do Sul State, this last one of main producers of soybean. Based on this, GHG emissions accounting from soybean cultivation and their potential environmental impacts depend on an inventory performing that presents a reality as close as possible in relation to Rio Grande do Sul State. Thus, this work aimed to trace how the soybean cultivation has developed for 20 years at Rio Grande do Sul State (between 1992 and 2013). During this research, a soybean growing, mainly on temporary croplands, that results in a different accounting in relation to current inventories that show soybean cultivation moving forward on forests areas was found. In this case, it was verified that this work, following The Intergovernmntal Panel on Climate Change (IPCC) methodology, the land use change (LUC) occurred in only 15.4% of the area, where soybean cultivation moved forward for 20 years. Finally, this work suggests future discussion for methodologies that encompass soybean cultivation advanced over wetland areas according to what is pointed out in this study.

Where is sugarcane cropping expanding in the brazilian cerrado, and why? A case study

ABSTRACT Sugarcane growing area in Brazil sharply expanded between 2000 and 2010 due to the increasing world demand for sugar and ethanol. Since this expansion of sugarcane is said to occur in areas covered by degraded pastures, it is likely not threatening the environment or food production. In order to verify this assumption, we investigate at farm and field levels which types of land use sugarcane cropping replaced between 2005 and 2010 and the reasons for farmers shifting or not shifting to sugarcane, as a case study in two counties in the state of Goiás. Within the studied period, sugarcane cropping expansion was related to large farms, lower risk perceived by farmers, and higher profitability compared with soybean and beef cattle-raising. For smallholders, particularly dairy farmers, the need to comply with the set-aside rules under Brazilian Forest Code (Código Florestal Brasileiro) made a shift to sugarcane less attractive, as it would have forced them to reduce farm cultivable area, with loss of incomes. From 30,408 ha under sugarcane surveyed, 45.7% had used to be pastures, 31% had previously been pastures rotated with soybean and maize, and 23.3% had been cropped exclusively with soybean or maize.

Reconstructing historical forest cover change in the Lower Amazon floodplains using the LandTrendr algorithm / Reconstrução histórica de mudanças na cobertura florestal em várzeas do Baixo Amazonas utilizando o algoritmo LandTrendr

The Amazon várzeas are an important component of the Amazon biome, but anthropic and climatic impacts have been leading to forest loss and interruption of essential ecosystem functions and services. The objectives of this study were to evaluate the capability of the Landsat-based Detection of Trends in Disturbance and Recovery (LandTrendr) algorithm to characterize changes in várzea forest cover in the Lower Amazon, and to analyze the potential of spectral and temporal attributes to classify forest loss as either natural or anthropogenic. We used a time series of 37 Landsat TM and ETM+ images acquired between 1984 and 2009. We used the LandTrendr algorithm to detect forest cover change and the attributes of "start year", "magnitude", and "duration" of the changes, as well as "NDVI at the end of series". Detection was restricted to areas identified as having forest cover at the start and/or end of the time series. We used the Support Vector Machine (SVM) algorithm to classify the extracted attributes, differentiating between anthropogenic and natural forest loss. Detection reliability was consistently high for change events along the Amazon River channel, but variable for changes within the floodplain. Spectral-temporal trajectories faithfully represented the nature of changes in floodplain forest cover, corroborating field observations. We estimated anthropogenic forest losses to be larger (1.071 ha) than natural losses (884 ha), with a global classification accuracy of 94%. We conclude that the LandTrendr algorithm is a reliable tool for studies of forest dynamics throughout the floodplain.

As várzeas amazônicas são um importante componente do bioma Amazônico, mas impactos antrópicos e climáticos têm levado à perda florestal e à interrupção de processos e serviços ecossistêmicos. O presente estudo teve como objetivos avaliar a aplicabilidade do algoritmo Landsat-based Detection of Trends in Disturbance and Recovery (LandTrendr) na detecção de mudanças na cobertura florestal de várzea no Baixo Amazonas, e analisar o potencial de atributos espectrais e temporais na classificação das perdas florestais em antrópicas ou naturais. Utilizamos uma série temporal de 37 imagens Landsat TM e ETM+, adquiridas entre 1984 e 2009. Aplicamos o algoritmo LandTrendr para detectar mudanças na cobertura florestal e extrair os atributos de "duração", "magnitude" e "ano de início" das mudanças, além de "NDVI ao final da série". A detecção se restringiu a áreas identificadas como cobertura florestal no início e/ou final da série. Os atributos derivados da série temporal foram classificados pelo algoritmo Support Vector Machine (SVM), diferenciando as perdas florestais antrópicas e naturais. A confiabilidade da detecção dos eventos de mudança foi consistentemente alta ao longo do rio Amazonas, e mais variável no interior da várzea. As trajetórias espectrais-temporais representaram fielmente os eventos de mudança na cobertura florestal, com base em averiguações em campo. A perda da cobertura florestal por causas antrópicas foi maior (1.071 ha) do que por causas naturais (884 ha), com exatidão global de classificação de 94%. Concluímos que o algoritmo LandTrendr é uma ferramenta confiável para aplicação em estudos de dinâmica da cobertura florestal de várzea.

Comparing how land use change impacts soil microbial catabolic respiration in Southwestern Amazon

Abstract Land use changes strongly impact soil functions, particularly microbial biomass diversity and activity. We hypothesized that the catabolic respiration response of the microbial biomass would differ depending on land use and that these differences would be consistent at the landscape scale. In the present study, we analyzed the catabolic response profile of the soil microbial biomass through substrate-induced respiration in different land uses over a wide geographical range in Mato Grosso and Rondônia state (Southwest Amazon region). We analyzed the differences among native areas, pastures and crop areas and within each land use and examined only native areas (Forest, Dense Cerrado and Cerrado), pastures (Nominal, Degraded and Improved) and crop areas (Perennial, No-Tillage, Conventional Tillage). The metabolic profile of the microbial biomass was accessed using substrate-induced respiration. Pasture soils showed significant responses to amino acids and carboxylic acids, whereas native areas showed higher responses to malonic acid, malic acid and succinic acid. Within each land use category, the catabolic responses showed similar patterns in both large general comparisons (native area, pasture and crop areas) and more specific comparisons (biomes, pastures and crop types). The results showed that the catabolic responses of the microbial biomass are highly correlated with land use, independent of soil type or climate. The substrate induced respiration approach is useful to discriminate microbial communities, even on a large scale.

¿Es la cobertura forestal conservada y restaurada por las zonas protegidas?: El caso de dos áreas silvestres protegidas en el Pacífico Central de Costa Rica / Is forest cover conserved and restored by protected areas?: The case of two wild protected areas in the Central Pacific of Costa Rica

Resumen:Cambios en el uso del suelo son principalmente consecuencia de las acciones antropogénicas. La actual transformación agrícola y urbana en Costa Rica ha generado preguntas acerca de la efectividad de la conservación y restauración dentro de las áreas protegidas. En este documento nosotros analizamos los patrones de cambio del uso del suelo entre tres periodos: 1997, 2005 y 2010 en términos de magnitud, dirección y velocidad a través de mapas categóricos generados por la foto-interpretación para dos áreas silvestres protegidas y sus áreas aledañas: Parque Nacional La Cangreja (LCNP), el Refugio de Vida Silvestre Rancho Mastatal (RMWR) y sus áreas aledañas (SA), esta última compuesta por área de un kilómetro de radio fuera de los límites de las áreas protegidas. La matriz que describe el paisaje dentro de las áreas protegidas es la cobertura natural, compuesta principalmente por la cobertura forestal y tacotales. Encontramos que la cobertura natural más abundante para ambas áreas protegidas fue cubierta forestal en todos los años estudiados. La estabilidad y las grandes áreas de la cubierta forestal en LCNP y RMWR para 2005 y 2010 reflejan que las políticas, las acciones de manejo y vigilancia tienen un impacto positivo en la conservación y restauración de los hábitats naturales en esta zona del Pacifico Central Costarricense. Sin embargo, la alta complejidad del paisaje de SA en 1997, 2005 y 2010 son una prueba de presión antropogénica sobre estas áreas protegidas y sugieren una ineficacia de los gobiernos locales para monitorear y disminuir los cambios de uso del suelo que podrían obstaculizar la gestión, conservación y restauración de especies dentro de las áreas protegidas.

Abstract:Changes in land use are mainly a consequence of anthropogenic actions. The current agricultural and urban transformations in Costa Rica have raised questions about the effectiveness of conservation and restoration within protected areas. Herein we analyzed the patterns of land use change between three periods: 1997, 2005 and 2010 in terms of magnitude, direction, and pace through categorical maps generated by the photo-interpretation for La Cangreja National Park (LCNP), Rancho Mastatal Wildlife Refuge (RMWR), and their surrounding areas (SA), this last compound of one kilometer radius outside the protected areas' boundaries. The matrix which describes the landscape within the protected areas is natural coverage, composed mainly by forest cover and thickets. We found that the most abundant natural cover for both protected areas was forest cover for all years tested. The stability and large areas of forest cover in LCNP and RMWR for 2005 and 2010, reflected that policies, management actions and vigilance, have a positive impact on the conservation and restoration of natural habitats in these Costa Rican Central Pacific areas. However, the high landscape complexity of the SA in 1997, 2005 and 2010 was an evidence of the anthropogenic pressure on these protected areas, and suggested the ineffectiveness of local governments to monitor and abate land use changes, that could hinder the management, conservation and restoration of species in the protected areas.

Mudanças no uso da terra decorrentes da expansão da cultura da cana-de-açúcar na região oeste do estado de São Paulo / Land use change from the sugar cane expansion in the western region of São Paulo state, Brazil

A demanda por alternativas energéticas tem aumentando a produção mundial de biocombustíveis e, consequentemente, o cultivo das culturas agrícolas. No Brasil, o lançamento dos veículos bicombustíveis propiciou a retomada da importância da produção de etanol e, consequentemente, numa nova fase de expansão do cultivo de cana-de-açúcar. Diversas questões relacionadas à sustentabilidade da produção de biocombustíveis têm sido discutidas na literatura, tais como o efeito na produção de alimentos e na segurança alimentar, o impacto ambiental da mudança do uso da terra e os efeitos sociais no campo. Este trabalho pretende analisar as mudanças no uso da terra na região Oeste Paulista, provocadas pela expansão do cultivo da cana-de-açúcar. Na última década (2003 a 2012), a região Oeste Paulista representou mais da metade da expansão dessa cultura no estado de São Paulo, maior estado produtor brasileiro. O método utilizado foi o Modelo Shift-Share, que, por meio da decomposição da variação das áreas, possibilitou calcular os efeitos escala e substituição das principais atividades em análise. Este trabalho revela que a expansão da cultura da cana-de-açúcar na região estudada ocorreu predominantemente pela substituição de áreas de pastagem e, consequentemente, da atividade pecuária.

The demand for energy alternatives to oil are increasing global biofuel production and, consequently, the biofuel crops cultivation. In Brazil, the emergence of flex-fuel vehicles resumed the importance of ethanol production, resulting in a new phase of Brazilian sugar cane crop expansion. Several issues related to the sustainability of biofuel production have been discussed in the literature, such as the effect on food production and food security, the environmental impact of land use change and social effects in the field. This study aims to analyze the land use change in the Oeste Paulista region, caused by the expansion of sugar cane cultivation. Between 2003 and 2012, the Oeste Paulista region represented more than half of the expansion of this crop in São Paulo state, the largest producer in Brazil. This paper used the Shift-Share model to decompose the agricultural areas variation and to calculate the replacement of the main activities analyzed. The results revealed that, in the analyzed region, the expansion of sugar cane area has occurred predominantly by replacing pasture and, consequently, by cattle activity.

Impact Assessment of Hydrology and Water Quality in the Saugahatchee Creek under Projected Land Use and Climate Change Scenarios Using WARMF.

The hydrology and water quality of a stream or reservoir can be affected due to rapid urbanization and land use change in its watershed. Climate change, if it occurs, is likely to have additional impacts on hydrology and water quality of the watershed system. In this study, a watershed model WARMF (Watershed Analysis Risk Management Framework) was applied to the Saugahatchee Creek Watershed which includes two stream branches that were listed on State of Alabama’s 303(d) list of impaired water for nutrients and organic enrichment/dissolved oxygen. WARMF model for the Saugahatchee Creek Watershed was developed and model calibration and validation were performed. The model was then used to investigate hydrologic and water quality response to two different land use scenarios (LU 2009 and LU 2030) and four statistically downscaled future climate scenarios derived from Canadian Global Coupled Model (CGCM3) and Hadley Centre Coupled Climate Model (HadCM3). Temperature, dissolved oxygen, total nitrogen, total phosphorus, and algal concentration were the water quality parameters simulated along with flow. Based on monthly average of daily predicted values, the effect due to land use change was not significant except for nutrient concentration. The monthly average of daily total phosphorus concentration for LU 2030 is predicted to increase up to 72% more than baseline (LU 2009) under past climate conditions (1981–2010). Based on model results, the monthly average of daily surface water temperature is predicted to rise for all future climate scenarios. The monthly average of daily flow is predicted to increase corresponding to CGCM3 (annual average increase of 88%) and decrease corresponding to HadCM3 scenarios (annual average decrease of -49%). Accordingly, nutrient concentration is expected to decrease corresponding to CGCM3 and increase corresponding to HadCM3 scenarios. DO concentration are predicted to fall up to 2.3 mg/l (monthly average), especially in summer for the four climate scenarios. Combined land use and climate change scenarios cause the increase in nutrient concentrations for future land use and climate scenarios (e.g., annual TP from 0.082 mg/l for the baseline to 0.203 mg/l for HadCM3 A2 20s scenario). Chlorophyll-a concentration during the growing season is expected to increase to 25.8 and 26.3 μg/l under HadCM3 A2 and B2 scenarios due to combined effect, respectively, in comparison to 18 μg/l for the baseline (1981–2010 and LU2009). The results of this study can be incorporated into watershed management and planning strategies.

Simulações espacialmente explícitas dos estoques de carbono orgânico de um LATOSSOLO BRUNO por meio da integração do modelo century com GIS / Spatially explicit simulations of soil carbon stocks in Humic Hapludox, using Century model and GIS

Os modelos de simulação, uma vez calibrados localmente, são ferramentas úteis para a avaliação dos impactos da agricultura sobre a dinâmica do carbono orgânico do solo (COS) e planejamento de sistemas agrícolas sustentáveis em escala regional. O presente trabalho teve como objetivo estudar a dinâmica do COS em um LATOSSOLO BRUNO Aluminoférrico típico muito argiloso, localizado em uma região de clima subtropical, por meio de simulações com o modelo Century - versão 4.0, apoiado em levantamentos históricos e técnicas de geoprocessamento e sensoriamento remoto. Verificou-se que, para o período atual, a mudança de uso do solo, representada pela conversão da vegetação nativa em agricultura, causou uma redução no conteúdo de carbono ao longo dos anos, sendo que as lavouras com maior tempo de exploração e submetidas ao preparo convencional apresentaram os menores estoques. Por outro lado, nas simulações futuras (ano 2058), verifica-se que as lavouras, quando sob manejos conservacionistas, podem recuperar, e até superar, os estoques de COS encontrados no solo sob vegetação nativa de campo.

Simulation models are useful tools for assessment of the impacts of agriculture on nutrient and soil organic C (SOC) dynamics. Results of simulation studies can be applied to develop sustainable agricultural systems. This study simulated SOC in clayey Humic Hapludox with Century model (version 4.0) in a subtropical climate, with support from historical soil and land-use surveys; GIS and remote sensing techniques. Major reductions in SOC stocks were observed after land under native vegetation was converted to agricultural use, especially under annual crops managed under conventional tillage. Simulations of these soils under current management to the year 2058 showed that soils under conservation systems (especially no tillage) can recover and in some cases even exceed the original SOC stocks under native vegetation.

Effect of swamp cultivation on distribution of anopheline larval habitats in Western Kenya.

Background & objectives: Malaria resurgence in highland regions of East Africa has been on increase. The spatio-temporal distribution of larval habitats of malaria vectors determines the distribution of adult vectors, hence, disease transmission. Vector’s ecology is necessary for strategic vector control through effective plan for source reduction. Mapping of the larval habitats is necessary for targeted control measures. The purpose of this study is to assess and compare the spatial and seasonal variations in anopheline larval habitats in Western Kenya. Methods: A comparative study was conducted on spatial distribution of GPS geo-located anopheline larval habitats in relation to highland and lowland environments. Land use types were categorized and all potential aquatic habitats of malaria vectors were examined in February, May, August and November 2004. Data analyses were performed using SAS JMP software. Results & discussion: Results showed a higher percentage of Anopheles gambiae s.s. (70.9%) than An. funestus (29.1%) in highland. In the lowland, An. gambiae s.l. comprised 60.1% while An. funestus represented 39.9%. The distribution of larval breeding is confined to the valley bottom in the highland while it was dispersed in the lowland. Land use type influenced the occurrence of positive breeding habitats in the highland. In the lowland, distribution was due to seasonality. We found high proportion of potential and positive breeding sites in cultivated swamps and farmlands at the highland site. These results suggest that swamp cultivation increases the availability and suitability of larval breeding habitats of malaria vectors, thus malaria transmission in the Western Kenya highlands environment.

Land use and land cover change detection in Karinca river catchment (NW Turkey) using GIS and RS techniques.

The basin of Karinca river, in the north-west of Turkey, covers an area of 29,840 ha. Pronounced changes in land use emerged as a result of the development of activities in the tourism sector in Turkey in the 1970’s. The basin has been significantly affected in the course of this process. This study was conducted in order to determine the land use changes (as well as the type of changes and their direction) occurring in the use of land in the Karinca river catchment for the period 1979-2007. The geographical data were gathered by using 1:25000 scale topographical maps as a basis. Thus, the existing soil and land use data from 1979 were processed on these bases and the the main materials rendering the land use were produced. Geometric verification was made by putting the previously prepared bases onto landsat ETM+ and satellite images of 2007. In the final stage, results pertaining to the changes in land use were obtained by overlapping the two sets of data. All processes were done using the ArcGIS Desktop v9.x program. According to the data of the year 1979, the catchment area consisted of 43.4% forest, 26.5% grassland, 18.3% olive groves, 10.6% agriculture and 1.2% built-up lands. Comparing these coverage with the data of 2007, show a clear shift among residential areas, olive groves and forest terrain. It was found that the agricultural areas, particularly along the shoreline, were converted into resort houses and that the olive groves (the dominant land use) shifted from lower regions to its upper sectors. All these changes caused loss of natural habitats leading to degradation.

Variación en la actividad microbiana por cambio de uso en suelos en sabanas, Llanos Orientales, Venezuela

Soil microbial activity variation after land use changes in savannah, Llanos Orientales, Venezuela. In West plains of Venezuela, the traditional land use of the Trachypogon savannah, has been the extensive grazing. The pressure over these savannahs to obtain a major animal productivity has stimulated the introduction of exotic forage plants, such as Brachiaria brizantha and Andropogon gayanus. In spite that great savannah extensions have been subject to this land use change, information about the effect that pastures and grazing activity have on microbial activity in these soils is scarce. So the objective of this study was to determine the impact that the extensive grazing and cover substitution have on microbial activity. The soil sampling was carried out during the dry and rainy seasons. The employed parameters to determine changes in soil microbial activity were the substrate induced respiration (SIR), basal respiration (BR), the dehydrogenase activity (DHS), the fluorescein diacetate hydrolysis (FDA) and the arginene ammonification (AA). The similarity of the structural soil characteristics studied allows us to infer, that the differences in the microbiological parameters are determined by climatic conditions and soil management. The results show that there is a low microbial activity in these soils. The rainy season caused an increase in all the microbiological parameters determined. B. brizantha made a greater contribution to soil carbon and promoted a greater heterotrophic activity. The extensive grazing and the low stocking rate in the West plain savannas did not affect the microbial activity in these soils. Rev. Biol. Trop. 59 (1): 1-15. Epub 2011 March 01.

En los llanos orientales de Venezuela la forma tradicional de uso de las sabanas de Trachypogon ha sido el pastoreo extensivo. La presión sobre éstas para obtener una mayor productividad animal ha estimulado la introducción de plantas exóticas para forrajes, tales como: Brachiaria brizantha y Andropogon gayanus. A pesar de que grandes extensiones de sabanas están siendo sometidas a este cambio de uso de la tierra, es escasa la información acerca del efecto que estas pasturas y la actividad de pastoreo tienen sobre la actividad microbiana en el suelo; por lo que el objetivo del presente estudio fue determinar el impacto que el pastoreo extensivo y la substitución de la cobertura nativa tienen sobre la actividad microbiana en estos suelos. El muestreo fue llevado a cabo durante las temporadas de sequía y lluvias. Los parámetros empleados para determinar cambios en la actividad microbiana fueron la respiración inducida por sustrato (RIS), la respiración basal (RB), la actividad de la deshidrogenasa (DHS), la hidrólisis del diacetato de fluorisceína (DAF) y la amonificación de la arginina (AA). La similitud de las características estructurales de los suelos estudiados nos permite inferir, que las diferencias en los parámetros microbiológicos, están determinadas por las condiciones climáticas y el manejo del suelo. Los resultados muestran que en estos suelos existe una baja actividad microbiana. La temporada lluviosa provocó un incremento en todos los parámetros microbiológicos determinados. B. brizantha hizo un mayor aporte de carbono al suelo y promovió una mayor actividad heterotrófica. El pastoreo extensivo y la baja carga animal en las sabanas de los llanos orientales de Venezuela no afectaron la actividad microbiana del suelo.

The effects of land use change on soil properties and organic carbon at Dagdami river catchment in Turkey.

This research was carried out in Dagdami river catchment located in the highlands of the Black sea region of Turkey. The objective of this study was to investigate the effects of representative land-use and land-cover types of largely deforested areas of Black sea region on soil properties. We measured these effects by quantifying some soil analyses were done on soil samples were taken at two depths (0-5 and 5-15 cm) and two aspects (N and S). According to the results of statistical analysis, satured hydraulic conductivity (Ksat), bulk density (BD), water stable aggregates (WSA), soil organic matter (SOM), soil organic carbon (SOC) and total nitrogen significantly change with land use type and aspect. Results have shown significantly higher values of saturated hydraulic conductivity (Ksat) in natural forest top soil (82.4 cm3.h-1 on average) compared to grasslands soils (8.4 cm3 h-1) and hazelnut garden soils (11.5 cm3 h-1) and corn field soils (30.0 cm3.h-1). It was determined that WSA was greater in the pasture and forest soils than in cultivated soils. In addition, Ksat was found the highest value in the forest soils at all aspects while, SOM and SOC of forest soils are higher than other land use types. On the other hand, amount of SOM and SOC of soils of grassland, hazelnut garden and corn field are low level and close to each other. Soils under hazelnut garden (1.1 g cm-3) and grassland (1.1 g cm-3) have higher bulk density than the adjacent soils under forests (0.7 g cm-3) and corn field (1.0 g cm-3) for two different aspects. Furthermore, after long term continuous cultivation of the natural forest soil, it was determined that some physical and chemical characteristics of it has been significantly changed.

Changes in population and land use over time in the Ecuadorian Amazon / Mudanças populacionais e de uso da terra na Amazônia Ecuatoriana

This paper draws upon a detailed longitudinal survey of households living on agricultural plots in the northern three provinces of the Ecuadorian Amazon, the principal region of colonization by migrants in Ecuador since the 1970s. Following the discovery of petroleum in 1967 near what has subsequently come to be the provincial capital and largest Amazonian city of Lago Agrio, oil companies built roads to lay pipelines to extract and pump oil across the Andes for export. As a result, for the past 30 years over half of both Ecuador's export earnings and government revenues have come from petroleum extracted from this region. But the roads also facilitated massive spontaneous in-migration of families from origin areas in the Ecuadorian Sierra, characterized by minifundia and rural poverty. This paper is about those migrants and their effects on the Amazonian landscape. We discuss the data collection methodology and summarize key results on settler characteristics and changes in population, land use, land ownership, technology, labor allocation, and living conditions, as well as the relationships between changes in population and changes in land use over time. The population in the study region has been growing rapidly due to both natural population growth (high fertility) and in-migration. This has led to a dramatic process of subdivision and fragmentation of plots in the 1990's, which contrasts with the consolidation of plots that has occurred in most of the mature frontier areas of the Brazilian Amazon. This fragmentation has led to important changes in land tenure and land use, deforestation, cattle raising, labor allocation, and settler welfare.

Este artigo baseia-se em uma pesquisa longitudinal sobre assentamentos agrícolas em três províncias no norte da Amazônia equatoriana, a principal região de colonização agrícola no país desde 1970. A partir da descoberta de reservas de petróleo em áreas próximas a Lago Agrio, capital provincial e maior cidade da Amazônia Equatoriana, empresas petrolíferas iniciaram a abertura de estradas e construção de oleodutos visando a extração, transporte através dos Andes e exportação de petróleo. A exploração petrolífera na Amazônia Equatoriana tem respondido, nos últimos trinta anos, por cerca da metade dos rendimentos com exportação e na arrecadação governamental. As estradas abertas na Amazônia facilitaram a imigração maciça e espontânea de famílias dos Andes equatorianos, uma região tradicionalmente caracterizada pela presença de minifúndios e pobreza rural. Este artigo discute a metodologia de coleta de dados e sumariza os principais resultados de pesquisas sobre esses imigrantes na Amazônia Equatoriana, especificamente em termos de mudanças nas características populacionais, uso e propriedade da terra, tecnologia, trabalho e padrão de vida, assim como relações entre características populacionais e uso da terra ao longo dos anos 90. O elevado crescimento populacional devido ao crescimento natural (alta fecundidade) e contínua imigração tem engendrado a subdivisão e fragmentação de lotes rurais desde 1990, em contraste ao processo de concentração de terra em diversas partes da Amazônia brasileira.

Avaliação de técnicas de segmentação e classificação automática de imagens landsat-tm no mapeamento do uso do solo na Amazônia1

Land use mapping is essential for the understanding of global change processes, especially in regions which are experiencing great pressure for development such as the Amazon. Traditionally, these mappings have been done using visual interpretation techniques of satellite imagery, that provide satisfactory results but are time-consuming and highly cost. In this paper, a technique of image segmentation based on region growing algorithm, followed by a per-field non-supervised classification, is proposed. Thus, the thematic classification is based on a set of image elements (pixels), benefiting from contextinformation, therefore minimizing the limitations of the digital processing techniques based on single pixels (per-pixel classification). This approach was evaluated in a typical test site of the Amazon region located to the north of Manaus, AM, using both original Landsat Thematic Mapper images and their decomposition into endmembers such as green vegetation, wood material, shade and soil, named mixture image in this paper. The results were validated by a reference map obtained from proved visual interpretation techniques of satellite imagery and by field check and indicated that automatic classification is feasible to map land use in Amazonia. Statistics tests indicated that there was significant agreement between the automated digital classifications and the reference map (at 95% confidence level).

O mapeamento do uso da terra é fundamental para o entendimento dos processos de mudanças globais, especialmente em regiões como a Amazônia que estão sofrendo grande pressão de desenvolvimento. Tradicionalmente estes mapeamentos têm sido feitos utilizando técnicas de interpretação visual de imagens de satélites, que, embora de resultados satisfatórios, demandam muito tempo e alto custo. Neste trabalho é proposta uma técnica de segmentação da imagens com base em um algoritmo de crescimento de regiões, seguida de uma classificação não-supervisionada por regiões. Desta forma, a classificação temática se refere a um conjunto de elementos (pixels da imagem), beneficiando-se portanto da informação contextual e minimizando as limitações das técnicas de processamento digital baseadas em análise pontual (pixel-a-pixel). Esta técnica foi avaliada numa área típica da Amazônia, situada ao norte de Manaus, AM, utilizando imagens do sensor "Thematic Mapper" - TM do satélite Landsat, tanto na sua forma original quanto decomposta em elementos puros como vegetação verde, vegetação seca (madeira), sombra e solo, aqui denominada imagem misturas. Os resultados foram validados por um mapa de referência gerado a partir de técnicas consagradas de interpretação visual, com verificação de campo, e indicaram que a classificação automática é viável para o mapeamento de uso da terra na Amazônia. Testes estatísticos indicaram que houve concordância significativa entre as classificações automáticas digitais e o mapa de referência (em tomo de 95% de confiança).