MODIS NDVI time-series allow the monitoring of Eucalyptus plantation biomass

The use of remote sensing is necessary for monitoring forest carbon stocks at large scales. Optical remote sensing, although not the most suitable technique for the direct estimation of stand biomass, offers the advantage of providing large temporal and spatial datasets. In particular, information on canopy structure is encompassed in stand reflectance time series. This study focused on the example of Eucalyptus forest plantations, which have recently attracted much attention as a result of their high expansion rate in many tropical countries. Stand scale time-series of Normalized Difference Vegetation Index (NDVI) were obtained from MODIS satellite data after a procedure involving un-mixing and interpolation, on about 15,000 ha of plantations in southern Brazil. The comparison of the planting date of the current rotation (and therefore the age of the stands) estimated from these time series with real values provided by the company showed that the root mean square error was 35.5 days. Age alone explained more than 82% of stand wood volume variability and 87% of stand dominant height variability. Age variables were combined with other variables derived from the NDVI time series and simple bioclimatic data by means of linear (Stepwise) or nonlinear (Random Forest) regressions. The nonlinear regressions gave r-square values of 0.90 for volume and 0.92 for dominant height, and an accuracy of about 25 m(3)/ha for volume (15% of the volume average value) and about 1.6 m for dominant height (8% of the height average value). The improvement including NDVI and bioclimatic data comes from the fact that the cumulative NDVI since planting date integrates the interannual variability of leaf area index (LAI), light interception by the foliage and growth due for example to variations of seasonal water stress. The accuracy of biomass and height predictions was strongly improved by using the NDVI integrated over the two first years after planting, which are critical for stand establishment. These results open perspectives for cost-effective monitoring of biomass at large scales in intensively-managed plantation forests. (C) 2011 Elsevier Inc. All rights reserved.

Distribution and agroclimatic characterization of potential cultivation regions of physic nut in Mexico

The purposes of this study were to determine the distribution and climatic patterns of current and future physic nut (Jatropha curcas) cultivation regions in Mexico, and to identify possible locations for in vivo germplasm banks establishment, using geographic information systems. Current climatic data were processed by Floramap software to obtain distribution maps and climatic patterns of regions where wild physic nuts could be found. DIVA-GIS software analyzed current climatic data (Worldclim model) and climatic data generated by CCM3 model to identify current and future physic nut cultivation regions, respectively. The distribution map showed that physic nut was present in most of the tropical and subtropical areas of Mexico, which corresponded to three agroclimatic regions. Climate types were Aw2, Aw1, and Bs1, for regions 1, 2 and 3, respectively. Nontoxic genotypes were associated with region 2, and toxic genotypes were associated with regions 1 and 3. According to the current and future cultivation regions identified, the best suitable ones to establish in vivo germplasm collections were the coast of Michoacán and the Isthmus of Tehuantepec, located among the states of Veracruz, Oaxaca and Chiapas.

DISTRIBUIÇÃO POTENCIAL DE OLIVEIRAS NO BRASIL E NO MUNDO

RESUMO A demanda pelo azeite de oliva tem sido crescente no mundo, principalmente no Brasil,aumentando a necessidade de expansão da área de plantio. Contudo, nas regiões que são tradicionalmente produtoras, não existe mais espaço, havendo necessidade de procurar novas áreas para plantio no mundo. Neste trabalho, foram identificadas áreas marginais para plantio no Brasil, utilizando modelagem de nicho ecológico, baseando-se em pontos de ocorrência levantados nas regiões produtoras da Europa, Estados Unidos, Austrália e América Latina (Chile, Argentina e Uruguai). Foram usados 346 pontos georreferenciados de ocorrência e planos de informação com dados climáticos (média de temperatura mínima do ar, média de temperatura máxima do ar - em oC - e total de precipitação pluviométrica - em mm) estacionais (primavera, verão, outono e inverno) do mundo, baixados do site do Worldclim. Os dados foram organizados e formatados em sistemas de informações geográficas, usando ArcGIS 10. Finalmente, foram elaborados mapas com a probabilidade de ocorrência de oliveiras no mundo. Foi feito também um mapa apenas da América do Sul, em que são apresentadas as zonas com maior potencial de ocorrência de oliveiras.

A matter of scale: apparent niche differentiation of diploid and tetraploid plants may depend on extent and grain of analysis

Aim: Emerging polyploids may depend on environmental niche shifts for successful establishment. Using the alpine plant Ranunculus kuepferi as a model system, we explore the niche shift hypothesis at different spatial resolutions and in contrasting parts of the species range. Location: European Alps. Methods: We sampled 12 individuals from each of 102 populations of R. kuepferi across the Alps, determined their ploidy levels, derived coarse-grain (100x100m) environmental descriptors for all sampling sites by downscaling WorldClim maps, and calculated fine-scale environmental descriptors (2x2m) from indicator values of the vegetation accompanying the sampled individuals. Both coarse and fine-scale variables were further computed for 8239 vegetation plots from across the Alps. Subsequently, we compared niche optima and breadths of diploid and tetraploid cytotypes by combining principal components analysis and kernel smoothing procedures. Comparisons were done separately for coarse and fine-grain data sets and for sympatric, allopatric and the total set of populations. Results: All comparisons indicate that the niches of the two cytotypes differ in optima and/or breadths, but results vary in important details. The whole-range analysis suggests differentiation along the temperature gradient to be most important. However, sympatric comparisons indicate that this climatic shift was not a direct response to competition with diploid ancestors. Moreover, fine-grained analyses demonstrate niche contraction of tetraploids, especially in the sympatric range, that goes undetected with coarse-grained data. Main conclusions: Although the niche optima of the two cytotypes differ, separation along ecological gradients was probably less decisive for polyploid establishment than a shift towards facultative apomixis, a particularly effective strategy to avoid minority cytotype exclusion. In addition, our results suggest that coarse-grained analyses overestimate niche breadths of widely distributed taxa. Niche comparison analyses should hence be conducted at environmental data resolutions appropriate for the organism and question under study.

Taxonomia e biogeografia da espécie politípica Herpsilochmus rufimarginatus (TEMMINCK, 1822) (Aves: THAMNOPHILIDAE)

The genus Herpsilochmus is composed mainly of cryptic species, among them is Herpsilochmus rufimarginatus, which is currently represented by four subspecies: H. r. rufimarginatus, H. r. frater, H. r. scapularis and H. r. exiguus. Differences in plumage and vocalization suggest that there are more than one species involved in this complex. Thus this and other subspecific taxa need urgent revision, the disjunct distribution of this species also allows us to infer the relationship between birds that occur in this biome and / or different centers of endemism. This study aims to make a taxonomic revision of the taxa included in the complex time Herpsilochmus rufimarginatus based on morphological, morphometric, vocals and geographical distribution of this bird. Besides creating distribution models current potential and make the reconstruction of the distribution bygone using ecological niche modeling, and testing the niche conservatism and divergence between different subspecies. Consultations for examination of the skins of specimens of the museums: Museum of Zoology, University of São Paulo (MZUSP), National Museum of Rio de Janeiro (MN) and Emilio Goeldi Museum of Pará (MPEG), and the skins deposited at the collection of Ornithological Federal University of Rio Grande do Norte (COUFRN). We studied the following measures length of specimens: exposed culmen, culmen and total culmen nostril, tarsus, wing and tail flattened. The voice analysis was performed with vocalizations banks and / or digital banks people where 17 voice parameters were measured. This information and more available in the literature were used to assemble a bunch of data under the limit distribution of taxa and generate ecological niche models. This analyzes carried out in the program Maxent, having as model selection criterion the AUC, and the models were greater than 0.80 are considered good models. Environmental data for the realization of the modeling were downloaded on the website of Worldclim. The morphometric information, vocals and geographic distribution point for the separation of these taxa to be considering various uni and multivariate analyzes. The potential distribution models performed well (AUC> 0.80), and its distribution associated with environmental characteristics of the Amazon forest and Atlantic forest (forests of south and southeast, northeast and forest). The reconstruction of the distribution indicates a possible contact between the southern part of the Atlantic forest in the northern part of the Amazon. The analysis of niche overlap showed a low overlap between taxa and comparisons between the null model and the generated overlay link probably occurring niche conservatism. The data suggest that the taxa that occur in the Amazon and Atlantic forest represent three distinct species

Dinâmica espaço-temporal e quantificação dos danos e perdas da murcha de Ceratocystis em eucalipto na produção de carvão vegetal

Pós-graduação em Ciência Florestal - FCA

Distribución potencial de los bosques de prosopis flexuosa en la provincia biogeográfica del monte

El objetivo de esta investigación fue generar un modelo de distribución potencial de los bosques de Prosopis flexuosa, en la provincia Biogeográfica del Monte, desde Catamarca hasta Mendoza, para luego comparar con distribuciones actuales y poder inferir acerca de los principales procesos y cambios en la distribución que pudieron haber sufrido estos bosques ya sea por causas naturales o antrópicas. Para obtener el mapa modelo se utilizó el software Maxent, el cual utiliza como datos los registros de presencia (georreferenciados) de la especie y las variables ambientales que se consideran relevantes para su distribución. Para correr el modelo, se utilizaron las variables bioclimáticas (obtenidas del sitio Worldclim) y las variables altura, pendiente, orientación, subórdenes de suelos y freática. Como registros, se utilizaron puntos de presencia de bosques (tomados con GPS) en diferentes zonas del Monte. El mapa de distribución potencial resultante concuerda con la ubicación de los principales valles, bolsones y llanuras del Monte, en donde se conoce la existencia actual de los bosques de Prosopis flexuosa. En comparación con estas distribuciones reales, existe una importante coincidencia pero, en general, el área abarcada por los bosques potenciales es superior a lo determinado por las imágenes actuales, como así también existen casos particulares en los cuales las probabilidades de ocurrencia de bosques son muy bajas y las imágenes nos muestran existencia de los mismos. A su vez, al comparar con fuentes y registros históricos, con documentos oficiales (cartas IGM) y estadísticas del ferrocarril se pueden inferir posibles procesos de desmontes, que estarían determinando la ausencia de bosques actuales en sitios donde nuestro mapa potencial presenta altas probabilidades.

Arctic Siberia: Modern pollen dataset and pollen spectra changes over the last 7,000 years from a lacustrine sediment core (southern Taymyr region)

Palaeoecological investigations in the larch forest-tundra ecotone in northern Siberia have the potential to reveal Holocene environmental variations, which likely have consequences for global climate change because of the strong high-latitude feedback mechanisms. A sediment core, collected from a small lake (radius ~100 m), was used to reconstruct the development of the lake and its catchment as well as vegetation and summer temperatures over the last 7100 calibrated years. A multi-proxy approach was taken including pollen and sedimentological analyses. Our data indicate a gradual replacement of open larch forests by tundra with scattered single trees as found today in the vicinity of the lake. An overall trend of cooling summer temperature from a ~2 °C warmer-than-present mid-Holocene summer temperatures until the establishment of modern conditions around 3000 years ago is reconstructed based on a regional pollen-climate transfer function. The inference of regional vegetation changes was compared to local changes in the lake's catchment. An initial small water depression occurred from 7100 to 6500 cal years BP. Afterwards, a small lake formed and deepened, probably due to thermokarst processes. Although the general trends of local and regional environmental change match, the lake catchment changes show higher variability. Furthermore, changes in the lake catchment slightly precede those in the regional vegetation. Both proxies highlight that marked environmental changes occurred in the Siberian forest-tundra ecotone over the course of the Holocene.

Flora y vegetación leñosa de los bosques de los Andes en la región de Madidi, La Paz (Bolivia)

Introducción: La región del Madidi en el noroeste de Bolivia es una de las más biodiversas del mundo, por incluir un amplio rango altitudinal desde los 200 hasta más de 6000 m, y floras de los Andes y la Amazonía, dos de las regiones biogeográficas más diversas del mundo. Esta región comprende territorios de tres áreas protegidas de interés nacional (Madidi, Apolobamba y Pilón Lajas), superpuestas a comunidades indígenas, campesinas, y áreas de exploración hidrocarburífera, lo cual ha generado muchos conflictos, incrementando sustancialmente las amenazas sobre los ecosistemas forestales en los últimos años. La falta de información ecológica y florística-estructural detallada de la vegetación boscosa a lo largo del gradiente altitudinal, no ha permitido una gestión eficaz de los mismos en la región. Además, información sobre la ecología de especies de los bosques, fundamental para efectuar actividades de manejo y/o conservación en la región, es escasa o vaga. Objetivos: Por tanto, se abordó el presente estudio en la región del Madidi para profundizar en el conocimiento de la vegetación boscosa, y de sus especies. Tratando de delimitar unidades discretas de vegetación, relacionando la composición florística con factores ambientales. Para lo cual se aprovechó la disponibilidad de un conjunto de datos de inventarios exhaustivos, florístico-estructurales, provenientes de parcelas forestales temporales, que cuentan con sus respectivos datos ambientales. Materiales y métodos: El juego de datos analizado comprende 415 parcelas de 0.1 ha, distribuidas entre 250 y 4350 m de altitud, que cuentan con información taxonómica y estructural de 2280 taxones de plantas leñosas. Empleamos en total 32 variables abióticas de cada parcela, de las cuales 18 son edáficas, 11 bioclimáticas basadas en parámetros de temperatura de WorldClim, y tres variables topográficas. Se descartaron las variables bioclimáticas de WorldClim basadas en parámetros de precipitación por mostrarse demasiado discordantes con la vegetación observada en campo. Para cada parcela se calcularon 10 variables bióticas, que son el número de especies, índice de Shannon Wiener, altura media de los individuos, área basal total, número de individuos, ratio individuos-tallos, número de lianas, número de palmeras, número de helechos arbóreos, y número de cactus; por una parte para establecer diferencias estructurales entre los grupos, y por otra para evaluar su utilidad como subrogados de condiciones ambientales particulares...