Reconstructing historical forest cover change in the Lower Amazon floodplains using the LandTrendr algorithm

ABSTRACTThe 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 várzeaforest 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.

Floristic and structure of an Amazonian primary forest and a chronosequence of secondary succession

ABSTRACT The analysis of changes in species composition and vegetation structure in chronosequences improves knowledge on the regeneration patterns following land abandonment in the Amazon. Here, the objective was to perform floristic-structural analysis in mature forests (with/without timber exploitation) and secondary successions (initial, intermediate and advanced vegetation regrowth) in the Tapajós region. The regrowth age and plot locations were determined using Landsat-5/Thematic Mapper images (1984-2012). For floristic analysis, we determined the sample sufficiency and the Shannon-Weaver (H'), Pielou evenness (J), Value of Importance (VI) and Fisher's alpha (α) indices. We applied the Non-metric Multidimensional Scaling (NMDS) for similarity ordination. For structural analysis, the diameter at the breast height (DBH), total tree height (Ht), basal area (BA) and the aboveground biomass (AGB) were obtained. We inspected the differences in floristic-structural attributes using Tukey and Kolmogorov-Smirnov tests. The results showed an increase in the H', J and α indices from initial regrowth to mature forests of the order of 47%, 33% and 91%, respectively. The advanced regrowth had more species in common with the intermediate stage than with the mature forest. Statistically significant differences between initial and intermediate stages (p<0.05) were observed for DBH, BA and Ht. The recovery of carbon stocks showed an AGB variation from 14.97 t ha-1 (initial regrowth) to 321.47 t ha-1 (mature forests). In addition to AGB, Ht was also important to discriminate the typologies.

Sôbre a ocorrência de um órgão cupuliforme, com bordos pelíferos, no colo dos «Seedlings» de Eucalyptus

1 - Os estudos sôbre o órgão cupuliforme datam de 1941, ocasião em que observávamos os "seedlings" de Eucalyptus tereticornis e Eucalyptus citriodora, com o propósito de colher material para estudos anatômicos comparativos das citadas espécies (1). 2 - Examinámos, a seguir, "seedlings" de outras espécies de Eucalyptus, comprovando em tôdas a existência do órgão cupuliforme. 3 -BRIOSI e WARMING, ambos mencionados por HABER-LANDT (4), assinalaram a presença de longos pêlos absorventes, no limite entre radícula e caulículo, respectivamente de plantas aquáticas e de Eucalyptus e outras Myrtaceae, sem contudo se reportarem à existência de qualquer órgão na região considerada. 4 - Revendo a bibliografia especializada, entre as quais a "A Critical Revision of the Genus Eucalyptus" de Maiden (6) e a "Eucalyptographia" do Baron Ferd. von Mueller (7), nenhuma referência encontrámos a respeito de qualquer órgão ou de pêlos absorventes, na região do colo dos "seedlings" de Eucalyptus. 5 - As sementes das 105 espécies constantes dêste trabalho foram obtidas no Serviço Florestal da Cia. Paulista de Estradas de Ferro, em Rio Claro, por nímia gentileza dos Drs. Edmundo Sampaio e Ruben Foot Guimarães, respectivamente Chefe e Encarregado da Secção de Genética do Serviço Florestal. 6 - As sementes foram postas num substrato de esfagno ou "musgo branco", reduzido a pó, coberto com papel de filtro e recebendo apenas água destilada, quer durante a germinação, quer durante o período de crescimento dos seedlings". 7 - Cientificámo-nos que no embrião o órgão cupuliforme já se encontra diferenciado, apresentando-se, nesse estágio, como um anel, disposto à volta do colo, em cujo centro se pode ver a ponta cônica da radícula. 8 - Os pêlos absorventes vão surgindo nos bordos do anel, à medida que este se expande, durante o processo de crescimento dos "seedlings". 9 - A forma, o tamanho, o diâmetro da bôca do órgão cupuliforme, bem como a quantidade e o comprimento dos pêlos absorventes dos seus bordos variam segundo as espécies estudadas. 10 - Do ponto de vista anatômico, a estrutura do órgão é simples. Consta de um parênquima cortical, revestido pela mesma epiderme que recobre a radícula e que se continua pelo caulículo. Os pêlos absorventes, que nascem nos bordos, são semelhantes aos que se produzem na zona pelífera da radícula. 11 - A importância ecológica do órgão é óbvia, uma vez que as sementes de Eucalyptus, sendo exalbuminadas, os "seedlings" devem, o quanto antes, adaptar-se prontamente ao solo, para evitar a solução de continuidade no processo fisiológico da nutrição.

Ocorrência do órgão cupuliforme com bordos pelífenos, no colo dos "seedlings" de algumas Myrtaceae

After verifing the presence of the cupuliform organ on the seedlings from 105 species of Eucalyptus (ACCORSI, 1955-56), the author concluded that it is a morphological characteristic of the genus, which is peculiar to the plants only in first stages of their life. In this paper, the author resumes his study carried out on 20 species of Myrtaceae, distributed among 13 genus and he could certify, until now, that, in relation to the cupuliform organ, they may divided in three groups: 1.° Group - Without cupuliform organ 1. Campomanesia aurea Berg 2. Eugenia campestris DC. 3. Eugenia tomentosa Camb. 4. Eugenia uniflora L. 5. Myrciaria edulis Berg 6. Myrciaria trunciflora Berg 7. Pitangueira-gigante - As it was difficulty to identify this species, I use its common name. 2.° Group - With rudiment of cupuli orm organ 1. Eugenia uvalha Camb. 2. Jambosa vulgaris DC. 3. Myrciaria cauliflora Berg 3.° Group - With full cupuliform organ 1. Amomyrtus luma (Mol) Legr. et Kaus. 2. Blepharocalyx angustifolius Berg 3. Britoa acida Berg 4. Callistemon speciosus DC. o. Callistemon viminalis Cheel. 6. Feijoa sellowiana Berg 7. Myrceugenia glaucescens (Camb.) Legrand 8. Myrrhinium rubriflorum Berg 9. Psidium guayava Raddi 10. Psidium littorale Raddi During his observations, he could identify also in many, seeds an "operculum", further observations about it will be published opportunely.

Observações preliminares sôbre a longevidade dos "Seedlings" de feijoeiro - Phaseolus vulgaris : em função das reservas cotiledonares

According previous studies about longevity in maize by ACCORSI e ADÂMOLI DE BARROS, (1961) the authors presents in this paper the results of work on longevity of seedlings of beans. Seeds were separated in three groups according their weight, as followings: small 80-120 mg; medium 130-140 mg and big 150-200 mg. The sowing of the seeds was made in pure sand and the seedlings were distributed in distil. water and in complete solution of Arnon and Hoagland. Each treatment was made in two replications with eight seedlings by treatment. At present time the following conclusions can be related: 1.°) - Eight days after germination, the cotiledones of all the seedlings started to fell down, fourteen days after, all cotiledones had fell down. 2.°) - Fifteen days after germination, the seedlings in nutritive solution showed better development than those in distil. water. Table I e II gives results. 3.°) - All seedlings in distil. water showed symptoms of N, Ca, Fe deficiencies. 4.°) - Twenty nine days after germination the seedlings in distil. water manifested exhaust trace, by falling of the leaves and death of some plants although the aplicai buds keep green. 5.°) - After thirty-one days the plants in nutritives solution was in better condition than those in distil. water, although some alteration aboved mentioned was observed. The causes of this alteration are being studied. 6.°) - In many plants in complet solution the seminal leaves showed clorosis initial and some with necrosis, although apical buds keeps in ativity. 7.°) - Symptoms of clorosis and necrosis in diferents stages were observed in all leaflet; these symptoms were more strong in the groups of little seed and medium seeds.

Enxertia de mesa de nogueira pecã em raízes de seedlings

Comprovou-se experimentalmente a possibilidade da realização da enxertia de mesa em nogueira peca, usando-se como porta-enxerto raízes de seedlings com um ano de idade. Dois experimentos permitiram essa conclusão. Em um deles, competiu-se a enxertia de mesa com a enxertia no próprio canteiro, fazendo-se para os primeiros o calejamento em ambiente úmido com e sem temperatura controlada. O resultado mais interessante para a enxertia de mesa, foi aquele obtido pela conservação dos enxertos recém feitos em ambiente úmido durante 25 a 30 dias à temperatura constante de 26ºC, conseguindo-se 60% de sobrevivência. Este valor não diferiu dos obtidos pela enxertia no próprio canteiro, com posterior transplante para o campo do viveiro aos 30 e 45 dias da data de enxertia. Quanto ao tamanho da raiz porta-enxerto, verificou-se que elas devem ter mais de 12 cm de comprimento, raízes com 9 cm resultaram em cerca de 20% de sobrevivência somente. Em todos os tratamentos experimentais, ficou demonstrado o baixo desenvolvimento da parte aérea da muda em seu primeiro ano de desenvolvimento no campo do viveiro.

A new species of Ibitermes (Isoptera, Termitidae) from the Atlantic forest, northeastern Brazil

The sterile castes of Ibitermes inflatus sp. nov. from Rio Tinto, State of Paraíba, Brazil are described and illustrated. This is the first record of a species of Ibitermes from the Brazilian northeast and from the Atlantic Forest biome. The absence of ridges in the molar plate of the left mandible and the presence of granules of sand and silt mixed with organic matter in advanced stage of decomposition in the digestive tube of workers suggest that the species is a typical humus feeding termite.

Euglossine bees (Hymenoptera, Apidae) in a remnant of Atlantic Forest in Paraná State, Brazil

Species composition, relative abundance, seasonal changes in the species abundance and scent association of male Euglossini collected in a semi-deciduous forest fragment in the north of the State of Paraná, southern Brazil, were recorded. Euglossine males were collected twice a month, for twelve months, from 8:00 am to 3:00 pm. The scents eucalyptol, eugenol, vanillin, methyl salicylate and benzyl acetate were used as baits. A total of 434 males distributed among 3 genera and 9 species were attracted to the chemical baits. Eufriesea violacea (Blanchard, 1840) (49.8%), Eulaema nigrita Lepeletier, 1841 (23.0%) and Euglossa pleosticta Dressler, 1982 (13.8%) were dominant in number of individuals. Among the non-dominant species, Euglossa fimbriata Rebêlo & Moure, 1995 was more common (9.0%), followed by E. cordata (L., 1758) (1.8%), E. truncata Rebêlo & Moure, 1995 (1.4%), E. melanotricha Moure, 1967 (0.7%), E. townsendi Cockerell, 1904 (0.23%) and Eufriesea auriceps Friese, 1899 (0.23%). In general, bees were more abundant in warm-wet season (September-March). Eufriesea violacea was the most seasonal species, showing activity through the warm-wet season, from October to February. Eucalyptol was the most attractive fragrance, which was responsible for 92.6% of all visits by euglossine bees.

Bromeliad-associated mosquitoes from Atlantic forest in Santa Catarina Island, southern Brazil (Diptera, Culicidae), with new records for the State of Santa Catarina

Bromeliad-associated mosquitoes (Diptera: Culicidae) in Atlantic Forest in Florianópolis, Santa Catarina, southern Brazil, were studied, examining plants of Vriesea philippocoburgi Wawra and Aechmea lindenii (E. Morren) Baker var. lindenii at secondary Atlantic rain forest, and A. lindenii and Vriesea friburgensis Mez var. paludosa (L. B. Smith) at "restinga" per month, during 12 months. No immature forms of mosquitoes were collected from A. lindenii in the secondary forest. Collections obtained 368 immature mosquitoes, none of them from A. lindenii from rain forest. Culex (Microculex) spp. constituted 79.8% of the total, Wyeomyia (Phoniomyia) spp. 17.93%, and Anopheles (Kerteszia) cruzii (Dyar & Knab, 1908) only 1.36%. The study shows the great predominance of species of medical importance not yet proved, and the small number of immature stages of anopheline mosquitoes. The rainfall, but not the mean temperatures, significantly influenced the quantity of mosquitoes from V. philippocoburgi. Significant differences between the quantities of immature forms of all the bromeliad species were found, and the shape of the plants could be important to the abundance of mosquitoes. All six species of Cx. (Microculex) found are recorded for the first time in the State of Santa Catarina, and all six species of Wyeomyia (Phoniomyia) are recorded for the first time in bromeliads in this state.

Diet of the ichthyofauna associated with marginal vegetation of a mangrove forest in southeastern Brazil

The objective of this study was to analyze the diet of fish species that use the mangrove vegetation for shelter and feeding in a river southeastern Brazil. The fieldwork, including collecting and underwater observations, was carried out in the dry (July and August 2004) and in the rainy season (February and March 2005) in order to assess the existence of seasonal variation in the diets. Seven kinds of food items were consumed, two of plant origin and five of animal origin. Crustaceans predominated in the diet of most species, either in the form of unidentified fragments or discriminated in eight groups. The predominance of species using mainly a single food source (crustaceans, principally Ostracoda and Tanaidacea) and the existence of seasonal variation in the diets of some species became very evident in the analysis food niche breadth, with a predominance of dietary specialists. In the Rio da Fazenda mangrove, the submersed marginal vegetation was used by the ichthyofauna as a locale for foraging, and principally as cover by bottom-feeding species. These species may be using the vegetation for protection from aerial and aquatic predators, or even from the pull of the current during the turn of the tide. In the study area, the great diversity of crustaceans constitutes an important food source for most fish species which adjusted their diet according to seasonal changes in food availability and to interactions with other species.

A new species of Alpaida (Araneae, Araneidae) from Caxiuanã National Forest, Oriental Amazonia, Brazil

Alpaida guto n. sp. is described based on males and females from State of Pará, Brazil. This species appears to be the most abundant Alpaida O. P.-Cambridge, 1889 species in Caxiuanã National Forest, eastern Amazonia. The males seem to be close to A. antonio Levi, 1988 but can be easily distinguished by the terminal apophysis with rounded distal lobe and long, slender basal prong; females differ from those of A. yotoco Levi, 1988 by the median lobe with a basal constriction and by the bilobed median plate.

Habitat use by a tree frog species of Scinax (Amphibia, Hylidae) at an urban forest fragment from south-eastern Brazil

We studied the pattern of habitat use by the tree frog Scinax aff. perereca. Fieldworks were performed from August 1996 to August 1997 at Parque das Mangabeiras, Belo Horizonte, State of Minas Gerais, southeastern Brazil. Calling males were observed in September, October and December 1996, February to April and June 1997. Females were found only in October 1996. Specimens were found perched on vegetation, on the ground or on stones near waterfall. At Parque das Mangabeiras, S. aff. perereca occupied nine types of substrata. The most frequently used substrata were shrubs, stones at the stream edges, and fallen trunks. The pattern of spatial occupation varied among months. Males were found calling in aggregations on the vegetation and spatial niche breadth was related to species abundance.

Sex ratio and morphological characteristics of rufous gnateaters, Conopophaga lineata (Aves, Passeriformes) in Atlantic forest fragments

Unequal sex ratios lead to the loss of genetic variability, decreasing the viability of populations in the long term. Anthropogenic activities often disturb the natural habitats and can cause alterations in sex ratio and morphological characteristics of several species. Forest fragmentation is a major conservation concern, so that understanding its effects in natural populations is essential. In this study, we evaluated the sex ratio and the morphological characteristics of Rufous Gnateaters (Conopophaga lineata (Wied, 1831)) in small and large forest fragments in Minas Gerais, Brazil. Birds (n = 89) were sexed by plumage characteristics and molecular markers. The molecular analysis showed that plumage is not a totally reliable method for sexing Rufous Gnateaters. We observed that sex ratio did not differ between large and small forest fragments, but birds in small fragments had larger wings and tarsus. Wing and tarsus changes may affect the movement ability of individuals within and among forest fragments. In conclusion, Rufous Gnateaters have been able to survive in both small and large Atlantic rain forest fragments without altering their sex ratio, but morphological changes can be prejudicial to their long term survival.

Soil invertebrates in southern Brazilian Araucaria forest - grassland mosaic: differences between disturbed and undisturbed areas

Soil invertebrate distribution in Araucaria forest, grassland and edge habitats was studied in both disturbed and undisturbed areas in southern Brazil. Mean-density and taxa compositions were verified. Invertebrate densities differed between grassland and the other two habitats in the undisturbed area but not across the disturbed one. At the disturbed area taxa differed between the grassland and the other two habitats. The undisturbed area, on the other hand, presented taxa differences only between the grassland and the forest habitats. Acari, Arachnida and Collembola were the most sensitive taxa for detecting differences across habitats in both areas. At the disturbed area, these taxa presented densities lowering from the forest to the grassland. At the undisturbed area the same taxa increased from the forest to the grassland. Coleoptera and Formicidae (Insecta) presented no difference between habitats at the studied taxonomic level.