Responses of transplanted native tree species to invasive alien grass removals in an abandoned cattle pasture in the Lacandon region, Mexico

We tested the early performance of 16 native early-, mid-, and late-successional tree species in response to four intensities of grass removal in an abandoned cattle pasture dominated by the introduced, invasive African grass, Cynodon plectostachyus, within the Lacandon rainforest region, southeast Mexico. The increase in grass removals significantly improved the performance of many species, especially of early-and mid-successional species, while performance of late-successional species was relatively poor and did not differ significantly among treatments. Good site preparation and at least one additional grass removal four months after seedling transplant were found to be essential; additional grass removals led to improved significantly performance of saplings in most cases. In order to evaluate the potential of transplanting tree seedlings successfully in abandoned tropical pastures, we developed a "planting risk index", combining field performance measurements and plantation cost estimations. Our results showed a great potential for establishing restoration plantings with many early-and mid-successional species. Although planting risk of late-successional species was considered high, certain species showed some possibilities of acclimation after 18 months and should be considered in future plantation arrangements in view of their long-term contributions to biodiversity maintenance and also to human welfare through delivery of ecosystem services. Conducting a planting risk analysis can help avoid failure of restoration strategies involving simultaneous planting of early-, mid-, and late-successional tree species. This in turn will improve cost-effectiveness of initial interventions in large-scale, long-term restoration programs.

Ozone sounding in the Metropolitan Area of Sao Paulo, Brazil: Wet and dry season campaigns of 2006

In the Metropolitan Area of Sao Paulo (MASP), located in southeastern Brazil, surface ozone concentrations are often well above the national air quality standards. In this experimental study, we attempted to characterize the vertical profile of atmospheric ozone and transport of the ozone plume in the boundary layer, using data from the first ozone soundings ever taken in the MASP. In 2006, we launched fifteen ozonesondes: eight from 15 to 18 May (dry season); and seven from 30 October to 1 November (wet season). Vertical ozone mixing ratios in the troposphere were approximately 40 ppb, reaching maximum values of approximately 60 ppb during the dry-season campaign and approximately 100 ppb during the wet-season campaign. In the first and second campaigns, the mean tropospheric ozone column abundance was 28.2 and 41.3 DU, respectively, which can be attributed to the considerable variation in the annual temperature cycle over the region. To determine the effect that biomass burning has on ozone concentrations over the MASP, we analyzed wind trajectories and satellite-derived fire counts. We cannot state unequivocally that biomass burning contributed to higher ozone concentrations above the boundary layer during the experimental campaigns. In the boundary layer, ozone concentrations increase with altitude, peaking at the base of the inversion layer, suggesting that local emissions of volatile organic compounds and nitrogen oxides play a significant role in the lower troposphere over MASP, influencing ozone formation not only at the surface but also vertically in the atmosphere and in distant regions. (C) 2012 Elsevier Ltd. All rights reserved.

Alien shrimps in evidence: new records of the genus Athanas Leach, 1814 on the coast of So Paulo, southern Brazil (Caridea: Alpheidae)

The occurrence of two alien alpheid shrimps of the genus Athanas Leach, 1814 [in Leach 1813-1814], the Indo-West Pacific A. dimorphus Ortmann, 1894 and the Eastern Atlantic A. nitescens (Leach, 1813 [in Leach 1813-1814]), on the coast of the state of So Paulo, Brazil, is reported. The presence of A. dimorphus extends the range of this species in the western Atlantic farther to the south in Brazil, whereas A. nitescens is reported for the first time in the western Atlantic, representing the second alien alpheid species on this side of the Atlantic and the twenty-first decapod crustacean introduced in Brazil. We provide morphological accounts of the material examined and illustrate the most important diagnostic characters of both species. An overview of the possible mechanisms of their introduction on the coast of So Paulo is also provided.

A snapshot of suspended sediment and fluid mud occurrence in a mixed-energy embayment, Tijucas Bay, Brazil

Along the southern Brazilian coast, Tijucas Bay is known for its unique muddy tidal flats associated with chenier plains. Previous field observations pointed to very high suspended sediment concentrations (SSCs) in the inner parts of the bay, and in the estuary of the Tijucas River, suggesting the presence of fluid mud. In this study, the occurrences of suspended sediments and fluid mud were examined during a larger-scale, high-resolution 2-day field campaign on 1-2 May 2007, encompassing survey lines spanning nearly 80 km, 75 water sampling stations for near-bottom density estimates, and ten sediment sampling stations. Wave refraction modeling provided qualitative wave energy estimates as a function of different incidence directions. The results show that SSC increases toward the inner bay near the water surface, but seaward near the bottom. This suggests that suspended sediment is supplied by the local rivers, in particular the Tijucas. Near-surface SSCs were of the order of 50 mg l(-1) close to the shore, but exceeded 100 mg l(-1) near the bottom in the deeper parts of the bay. Fluid mud thickness and location given by densimetry and echo-sounding agreed in some places, although being mostly discordant. The best agreement was observed where wave energy was high during the campaign. The discrepancy between the two methods may be an indication for the existence of fluid mud, which is recorded by one method but not the other. Agreement is considered to be an indication of fluidization, whereas disagreement indicates more consolidation. Wave modeling suggests that waves from the ENE and SE are the most effective in supplying energy to the inner bay, which may induce the liquefaction of mud deposits to form fluid mud. Nearshore mud resuspension and weak horizontal currents result in sediment-laden offshore flow, which explains the higher SSCs measured in the deeper parts of the bay, besides providing a mechanism for fine-sediment export to the inner shelf.

Presença e distribuição de espécies exóticas na zona de influência de duas trilhas no Parque Nacional da Serra do Cipó - MG

The presence of visitors in national parks is desirable and agrees with their management objectives. However, areas and paths under the influence of visitors are sites with a great possibility of change in the composition of vegetation due to the effects caused by the influence of walking, bicycles and horseback riding. In this work, two trails of the Serra do Cipo National Park were evaluated with the aim of studying and knowing the distribution of native and exotic species in their areas of influence. The theme of biological invasions in protected areas has been an important focus of studies since they represent a threat to biodiversity. The results show differences in the presence of exotic plants and conservation conditions between the two tracks studied.

PHENOLOGY AND FRUIT TRAITS OF ARCHONTOPHOENIX CUNNINGHAMIANA, AN INVASIVE PALM TREE IN THE ATLANTIC FOREST OF BRAZIL

The Australian palm Archontophoenix cunninghamiana was introduced into Brazil as an ornamental species, and became a dangerous invader of remnant Atlantic forest patches, demanding urgent management actions that require careful planning. Its fruits are greatly appreciated by generalist birds and its sudden eradication could be as harmful as its permanence in the native community. Our hypothesis was that A. cunninghamiana phenology and fruit traits would have facilitated the invasion process. Hence the aim of the study was to characterize the reproductive phenology of the palm by registering flowering and fruiting events, estimating fruit production, and evaluating fruit nutritional levels. Phenological observations were carried out over 12 months and analyzed statistically. Fruit traits and production were estimated. Pulp nutritional levels were determined by analyzing proteins, lipids, and carbohydrates. Results showed constant flowering and fruiting throughout the year with a weak reproductive seasonality. On average, 3651 fruits were produced per bunch mainly in the summer. Fruit analysis revealed low nutrient contents, especially of proteins and lipids compared with other Brazilian native palm species. We concluded that the abundant fruit production all year round, and fruit attractivity mainly due to size and color, :may act positively on the reproductive performance and effective dispersion of A. cunninghamiana. As a management procedure which would add quality to frugivore food resources we suggest the replacement of A. cunninghamiana by the native palm Euterpe edulis, especially in gardens and parks near to Atlantic forest fragments.

Neotectonics in the northern equatorial Brazilian margin

An increasing volume of publications has addressed the role of tectonics in inland areas of northern Brazil during the Neogene and Quaternary, despite its location in a passive margin. Hence, northern South America plate in this time interval might have not been as passive as usually regarded. This proposal needs further support, particularly including field data. In this work, we applied an integrated approach to reveal tectonic structures in Miocene and late Quaternary strata in a coastal area of the Amazonas lowland. The investigation, undertaken in Marajo Island, mouth of the Amazonas River, consisted of shallow sub-surface geophysical data including vertical electric sounding and ground penetrating radar. These methods were combined with morphostructural analysis and sedimentological/stratigraphic data from shallow cores and a few outcrops. The results revealed two stratigraphic units, a lower one with Miocene age, and an upper one of Late Pleistocene-Holocene age. An abundance of faults and folds were recorded in the Miocene deposits and, to a minor extent, in overlying Late Pleistocene-Holocene strata. In addition to characterize these structures, we discuss their origin, considering three potential mechanisms: Andean tectonics, gravity tectonics related to sediment loading in the Amazon Fan, and rifting at the continental margin. Amongst these hypotheses, the most likely is that the faults and folds recorded in Marajo Island reflect tectonics associated with the history of continental rifting that gave rise to the South Atlantic Ocean. This study supports sediment deposition influenced by transpression and transtension associated with strike-slip divergence along the northern Equatorial Brazilian margin in the Miocene and Late Pleistocene-Holocene. This work records tectonic evidence only for the uppermost few ten of meters of this sedimentary succession. However, available geological data indicate a thickness of up to 6 km, which is remarkably thick for an area regarded as a passive margin. (C) 2012 Elsevier Ltd. All rights reserved.

Habitat use by Sharp-tailed Tyrant (Culicivora caudacuta), and Cock-tailed Tyrant (Alectrurus tricolor) in the Cerrado of Southeastern Brazil

Habitat use by Sharp-tailed Tyrant (Culicivora caudacuta), and Cock-tailed Tyrant (Alectrurus tricolor) in the Cerrado of Southeastern Brazil. Obligatory grassland birds are dependent on a limited set of native habitats that are disappearing almost everywhere. We examined the use of macrohabitat and microhabitat by two threatened species of flycatchers, the Sharp-tailed Tyrant, Culicivora caudacuta and the Cock-tailed Tyrant, Alectrurus tricolor in a preserved area of cerrado. We generated logistic regression models to explain the presence of these species through variables of microhabitat. Both flycatchers occurred mainly in grassland areas and favored areas with a low density of palms (Attalea geraensis) and trees. The Sharp-tailed Tyrant also favored areas with a high density of low shrubs (< 1 m) and less exposed soil. The positive relationship found between the presence of Sharp-tailed Tyrant and soil cover may indicate the importance of litter and understory vegetation for shelter and food. The conservation of both flycatcher species in the study area should benefit from controlling palm density and the maintenance of grasslands with low shrubs.

Nest stolen: the first observation of nest predation by an invasive exotic marmoset (Callithrix penicillata) in an agricultural mosaic

Invasive exotic species can negatively impact local biodiversity. We present here a report of a nest predation of an endemic bird species, variable oriole (Icterus pyrrhopterus) by the introduced black-tufted marmoset (Callithrix penicillata)in an agricultural landscape highly disturbed by human activities. Two nestlings were predated, by adults of the introduced marmoset during two alternate days. Antipredator behavior and vocal mimicry were observed in variable oriole, while copulation was observed in black-tufted marmoset during the predation. The use of mobbing against predators by I. pyrrhopterus was observed and it is described here by the first time. The potential impact of the introduced marmosets to local biodiversity is discussed.

Comparing the establishment of an invasive and an endemic palm species in the Atlantic rainforest

Background: Biological invasions are one of the major causes of biodiversity loss, yet remain rather understudied in tropical environments. The Australian palm tree Archontophoenix cunninghamiana was introduced into Brazil for ornamental purposes, but has become an invasive species in urban and suburban forest patches. The substitution of A. cunninghamiana by the native palm Euterpe edulis has been proposed as a management action. Aims: We aimed to evaluate the regeneration potential of these two palm species in an Atlantic forest remnant in south-eastern Brazil where both species occur. Methods: We compared seedling establishment and seed longevity of both species through seed sowing, and also measured the contribution of A. cunninghamiana to the local seed rain and seed bank. Results: Nearly half of the non-anemochoric diaspores collected from the seed rain belonged to A. cunninghamiana, which represented a high propagule pressure in the community. The distribution of the alien palm seeds in the seed rain correlated with the distribution of nearby young and adult individuals inside the forest. Neither A. cunninghamiana nor E. edulis appeared to have a persistent seed bank in a burial experiment; seedling survival experiments suggested a much better performance for A. cunninghamiana, which had a survival rate of ca. 30% compared with a rate of only 3.5% for E. edulis. Conclusions: The results suggest a higher regeneration capacity for the alien palm over the native species when co-occurring in a forest fragment. Management actions are thus proposed to reduce a potential biological invasion process.

Plant invasions research in Latin America: fast track to a more focused agenda

While many developed countries have invested heavily in research on plant invasions over the last 50 years, the immense region of Latin America has made little progress. Recognising this, a group of scientists working on plant invasions in Latin America met in Chile in late 2010 to develop a research agenda for the region based on lessons learned elsewhere. Our three main findings are as follows. (1) Globalisation is inevitable, but the resultant plant introductions can be slowed or prevented by effective quarantine and early intervention. Development of spatially explicit inventories, research on the invasion process and weed risk assessments can help prioritise and streamline action. (2) Eradication has limited application for plants and control is expensive and requires strict prioritisation and careful planning and evaluation. (3) Accepting the concept of novel ecosystems, new combinations of native and introduced species that no longer depend on human intervention, may help optimise invasive species management. Our vision of novel ecosystem management is through actions that: (a) maintain as much native biodiversity and ecosystem functionality as possible, (b) minimise management intervention to invasives with known impact, and (c) maximise the area of intervention. We propose the creation of a Latin American Invasive Plants Network to help focus the new research agenda for member countries. The network would coordinate research and training and establish funding priorities, develop and strengthen tools to share knowledge, and raise awareness at the community, governmental and intergovernmental levels about the social, economic and environmental costs of plant invasions.