Disentangling the drivers of reduced long-distance seed dispersal by birds in an experimentally fragmented landscape

Seed dispersal is a crucial component of plant population dynamics. Human landscape modifications, such as habitat destruction and fragmentation, can alter the abundance of fruiting plants and animal dispersers, foraging rates, vector movement, and the composition of the disperser community, all of which can singly or in concert affect seed dispersal. Here, we quantify and tease apart the effects of landscape configuration, namely, fragmentation of primary forest and the composition of the surrounding forest matrix, on individual components of seed dispersal of Heliconia acuminata, an Amazonian understory herb. First we identified the effects of landscape configuration on the abundance of fruiting plants and six bird disperser species. Although highly variable in space and time, densities of fruiting plants were similar in continuous forest and fragments. However, the two largest-bodied avian dispersers were less common or absent in small fragments. Second, we determined whether fragmentation affected foraging rates. Fruit removal rates were similar and very high across the landscape, suggesting that Heliconia fruits are a key resource for small frugivores in this landscape. Third, we used radiotelemetry and statistical models to quantify how landscape configuration influences vector movement patterns. Bird dispersers flew farther and faster, and perched longer in primary relative to secondary forests. One species also altered its movement direction in response to habitat boundaries between primary and secondary forests. Finally, we parameterized a simulation model linking data on fruit density and disperser abundance and behavior with empirical estimates of seed retention times to generate seed dispersal patterns in two hypothetical landscapes. Despite clear changes in bird movement in response to landscape configuration, our simulations demonstrate that these differences had negligible effects on dispersal distances. However, small fragments had reduced densities of Turdus albicollis, the largest-bodied disperser and the only one to both regurgitate and defecate seeds. This change in Turdus abundance acted together with lower numbers of fruiting plants in small fragments to decrease the probability of long-distance dispersal events from small patches. These findings emphasize the importance of foraging style for seed dispersal and highlight the primacy of habitat size relative to spatial configuration in preserving biotic interactions

Modelamiento geométrico del cambio de coordenadas UTM causadas por mudanza de referencial geodésico: Caso Sirgas - Chile

Los avances tecnológicos de las últimas décadas han permitido determinar cada vez con mayor precisión, las dimensiones, forma y campo gravitacional de la Tierra. Estas nuevas tecnologías y sus métodos de observación y análisis, admiten el uso de distintos Sistemas Geodésicos de Referencia (SGR) que hacen posible la descripción de posición de cualquier punto sobre la superficie terrestre con precisiones sub-métricas. Actualmente en Chile hay diversos SGR usados en la generación de productos cartográficos, tales como el Datum Provisorio Sudamericano de 1956 (PSAD56), el Datum Sudamericano de 1969 (SAD69) y el nuevo Sistema de Referencia Geocéntrico para las Américas (SIRGAS). Este último, a diferencia de los dos anteriores, es un sistema geocéntrico actual, compatible en precisión y exactitud con las modernas tecnologías de posicionamiento. Actualmente, el Instituto Geográfico Militar de Chile (IGM) promueve la adopción del nuevo sistema SIRGAS e indica el modelo y los parámetros oficiales de transformación para la cartografía nacional a escala 1:50.000. Con la adopción de SIRGAS, una cantidad significativa de documentos cartográficos, en pleno uso actualmente, deberán ser transformados o adecuados al nuevo referencial geodésico. Existen diversos métodos y modelos, propuestos en la geodesia, para la transformación de valores de coordenadas asociados a un SGR en valores de coordenadas asociados a otro SGR. En el presente trabajo se realiza un análisis del impacto del cambio de referencial geodésico SIRGAS en la geometría de los rasgos representados en el sistema de proyección Universal Transversa de Mercator, para el caso de Chile continental sudamericano. Posteriormente, se definen modelos y parámetros alternativos al procedimiento clásico de transformación de coordenadas. Los resultados muestran que los modelos alternativos son eficaces en el caso de Chile

Use of secondary forests by understory birds in a fragmented landscape in central Amazonia

Rates of deforestation in the Brazilian Amazon have increased since 1991 and forecasts are not optimistic about the slowing of this process. Some authors believe that the Amazon may be experiencing a massive process of species extinction. However, the deforestation is accompanied by the expansion of secondary forests that are established in the abandoned areas. The trend is an increase in secondary forests cover, resulting in a mosaic of primary forest (FP) and fragments separated by an array of secondary forests (FS). In this scenario, the prediction of a massive extinction could be wrong if many species could survive in the secondary forests. To assess the importance of FS for the understory birds we sampled areas in regeneration and a continuous forest of a fragmented landscape. We conducted mist netting (24 nets/day) for six consecutive days/month, for 8 months (May-November) in 2009. Some forest species as do not seem to be adapted to the secondary forest environment and their occurrences are restricted to continuous forest environments. But most focal species showed no significant difference in apparent survival rates between the enviroments, suggesting that these species inhabit the secondary forest and the primary forest similarly. Because most of the matrix in fragmented landscapes are composed by secondary forests, such results highlights the conservation value that these habitats present in the long term. Thus, FS should be regarded as dynamic matrix that not only allows the movement of individuals but also function as habitat for many species typical of FP.Na Amazônia, as taxas de desmatamento crescem desde 1991 e as previsões não são otimistas quanto à desaceleração desse processo. A devastação da floresta é acompanhada de uma expansão de florestas secundárias (FS) que se estabelecem nas áreas abandonadas. A tendência é um aumento de florestas secundárias, resultando num mosaico de floresta contínua e fragmentos separados por uma matriz de FS. Nesse cenário, autores acreditam que a Amazônia pode passar por um processo massivo de extinção de espécies. Por outro lado, a previsão de um processo massivo de extinção pode ser equivocada, pois muitas espécies florestais poderiam sobreviver nas florestas secundárias. Para avaliar o valor das florestas secundárias para espécies florestais amostramos por oito meses com redes de neblina uma capoeira (FS) em regeneração e uma floresta primária (FP) de uma paisagem fragmentada. Algumas espécies não foram capturadas na capoeira e aparentemente evitam esse tipo de hábitat. No entanto, a maioria das espécies do grupo focal não apresentou diferença na sobrevivência aparente entre os ambientes, o que nos indica que estão habitando a capoeira e a floresta primária da mesma forma. Na realidade amazônica, onde grande parte da matriz é composta por floresta secundária, a matriz tem valor para conservação e deve ser analisada como um elemento dinâmico que não apenas permite a movimentação de indivíduos, mas também serve de hábitat para muitas espécies de floresta primária. Mas ressaltamos que é fundamental a preservação de áreas de floresta primária que servirão de fonte às florestas secundárias adjacentes

Comorbilidades em doentes com doença pulmonar obstrutiva crónica estádio IV

ResumoIntroduçãoA doença pulmonar obstrutiva crónica (DPOC) está associada a várias comorbilidades, contudo, a prevalência das mesmas varia entre os estudos.ObjetivoDeterminar a prevalência das diversas comorbilidades em doentes com DPOC estádio IV do The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2010, seguidos em regime de ambulatório, num hospital universitário.MétodosFoi concebido e aplicado um questionário com o objetivo de caracterizar a DPOC e suas comorbilidades. Os dados foram completados por consulta do processo clínico.ResultadosForam incluídos 89 doentes (87% do género masculino), com média etária de 68 anos, 79% dos quais ex-fumadores. O valor de volume expiratório máximo por segundo (VEMS) médio foi de 38% do previsto e todos os doentes apresentavam insuficiência respiratória crónica. Trinta e cinco doentes (39%) apresentavam exacerbações frequentes.Trinta e sete doentes (42%) tinham apresentado pelo menos um internamento por exacerbação da sua doença respiratória no ano anterior e 66 doentes (74%) nos últimos 5 anos.A maioria dos doentes (97%) apresentava pelo menos uma comorbilidade, com uma média de 4 comorbilidades por doente e um índice de Charlson médio de 2.As comorbilidades mais frequentes foram doenças cardiovasculares (69%), patologia osteoarticular (51%), disfunção erétil (48%), síndrome da apneia do sono (43%), dislipidémia (35%), cataratas (31%), refluxo gastro-esofágico (29%) e diabetes (20%).Os exacerbadores frequentes apresentaram um risco aumentado de terem 2 ou mais comorbilidades (Odds ratio de 5), bem como uma maior prevalência de refluxo gastro-esofágico (p=0,006) e um maior número de internamentos no último ano e nos 5 anos anteriores (p <0,001).ConclusãoEste estudo confirmou a elevada prevalência e a associação de comorbilidades em doentes com DPOC GOLD estádio IV, justificando a necessidade de uma abordagem terapêutica abrangente e integradora.AbstractIntroductionChronic Obstructive Pulmonary Disease (COPD) is associated with several co-morbidities, however their prevalence varies from one study to another.AimTo determine the prevalence of several co-morbidities in patients with COPD severity score GOLD 4 (The Global Initiative for Chronic Obstructive Lung Disease, 2010) followed in ambulatory care, in a University Hospital.MethodsA questionnaire was designed and carried out in order to characterize COPD and its co-morbidities. Clinical files were consulted in order to complete the data.Results89 patients (87% male) with a mean age of 68 years old, of which 79% were ex-smokers, were included. The average value of FEV1 (forced expiratory volume in one second) was 38% of the expected values and all the patients presented chronic respiratory failure. Thirty-five patients (39%) were frequent exacerbators.Thirty-seven patients (42%) had been hospitalized at least once due to exacerbation of their respiratory disease in the previous year, and 66 patients (74%) hospitalized in the previous five years.Most of the patients (97%) presented at least one comorbidity, with an average of 4 co-morbidities per patient and an average Charlson index of 2.The most frequent co-morbidities were cardiovascular diseases (69%), osteoarticular pathology (51%), erectile dysfunction (48%), sleep apnoea syndrome (43%) dyslipidaemia (35%), cataracts (31%), gastroesophageal reflux (29%) and diabetes (20%).Frequent exacerbators presented an increased risk of having two or more co-morbidities (Odds Ratio of 5), as well as a higher prevalence of gastroesophageal reflux (p=0.0006) and more hospitalizations in the last year and in the previous 5 years (p <0.001).ConclusionThis study confirmed the high prevalence and the association of co-morbidities in patients with COPD severity score GOLD 4, thus justifying the need for a comprehensive and integrating therapeutic approach

Appendix B. Corrected Akaike information criterion (AICc) for models used to analyze effects of fragmentation on seedling establishment.

Corrected Akaike information criterion (AICc) for models used to analyze effects of fragmentation on seedling establishment

Appendix A. Corrected Akaike information criterion (AICc) for models used to analyze seedling abundance as a result of seed and safe-site limitation.

Corrected Akaike information criterion (AICc) for models used to analyze seedling abundance as a result of seed and safe-site limitation

Effects of forest fragmentation on the seedling recruitment of a tropical herb: Assessing seed vs. safe-site limitation

Studies simultaneously evaluating the importance of safe-site and seed limitation for plant establishment are rare, particularly in human-modified landscapes. We used spatially explicit neighborhood models together with data from 10 0.5-ha mapped census plots in a fragmented landscape spanning 1000 km2 to (1) evaluate the relative importance of seed production, dispersal, and safe-site limitation for the recruitment of the understory herb Heliconia acuminata; and (2) determine how these processes differ between fragments and continuous forests. Our analyses demonstrated a large degree of variation in seed production, dispersal, and establishment among and within the 10 study plots. Seed production limitation was strong but only at small spatial scales. Average dispersal distance was less than 4 m, leading to severe dispersal limitation at most sites. Overall, safe-site limitation was the most important constraint on seedling establishment. Fragmentation led to a more heterogeneous light environment with negative consequences for seedling establishment but had little effect on seed production or dispersal. These results suggest that the effects of fragmentation on abiotic processes may be more important than the disruption of biotic interactions in driving biodiversity loss in tropical forests, at least for some functional groups. These effects may be common when the matrix surrounding fragments contains enough tree cover to enable movement of dispersere and pollinators. © 2010 by the Ecological Society of America