Fluctuating asymmetry: A tool for impact assessment on fish populations in a tropical polluted bay,Brazil

Fluctuating asymmetry (FA), which can be defined as random morphologic changes on bilateral symmetry plan of paired morphometric and meristic characters in response of environmental disturbances, is an alternative tool to traditional methods of environmental health assessment that has an interesting potential to appraise the state of adaptation of a population before that acute contaminations affect the whole community or ecosystem. This study aimed to assess the occurrence of FA in three morphometric and three meristic characters of the Corocoro grunt Orthopristis ruber (Cuvier, 1830), and compare the deviations in bilateral symmetry of this reef-associated and omnivorous in Guanabara Bay (Brazil), the venue for various outdoor aquatic sports during the 2016 Olympic Games. Five indexes of FA were tested over the six characters of 66 O. ruber, which were caught during the dry and wet seasons of 2011 and at three areas Guanabara Bay of different environmental characteristics. In addition to validate the existence of FA for O. ruber, our findings revealed significant deviations in the bilateral symmetry according to the FA indexes and fish characters. Together with the FA1 index, the number of gill rakers and the number of rays of the pectoral fin provided the best methodological approach to address the levels of FA in O. ruber as a response to environmental stressors in each region. The levels of FA in O. ruber was significantly lower in the Urca region (less impacted) than for individuals caught near the Paquetá Island and Rio-Niterói Bridge sites (more degraded). Partial Redundancy Analysis also shows that the fish characters are affected in different ways by environmental stressors, but especially in response to the levels of dissolved oxygen and, secondarily, to water transparency, and that Paquetá Island is apparently less impacted than the site near the Rio-Niterói Bridge. Our results confirm the potential of FA to be used as a tool to detect environmental effects on a reef-associated fish species in a tropical polluted bay, but further studies are necessary to validate our findings for other species and ecosystems.     

Genetically modified crops and small-scale farmers: main opportunities and challenges

Although some important features of genetically modified (GM) crops such as insect resistance, herbicide tolerance, and drought tolerance might seem to be beneficial for small-scale farmers, the adoption of GM technology by smallholders is still slight. Identifying pros and cons of using this technology is important to understand the impacts of GM crops on these farmers. This article reviews the main opportunities and challenges of GM crops for small-scale farmers in developing countries. The most significant advantages of GM crops include being independent to farm size, environment protection, improvement of occupational health issues, and the potential of bio-fortified crops to reduce malnutrition. Challenges faced by small-scale farmers for adoption of GM crops comprise availability and accessibility of GM crop seeds, seed dissemination and price, and the lack of adequate information. In addition, R&D and production costs in using GM crops make it difficult for these farmers to adopt the use of these crops. Moreover, intellectual property right regulations may deprive resource poor farmers from the advantages of GM technology. Finally, concerns on socio-economic and environment safety issues are also addressed in this paper.     

Apomixis versus sexuality in blackberries (Rubus subgen.Rubus,Rosaceae)

InRubus L. a connection seems to exist between the degree of meiotic disturbances on the one hand, and the production of unreduced embryo sacs, pollen fertility and relative seed set on the other hand. Severe meiotic disturbances commonly encountered in apomictic taxa decrease pollen fertility and thereby seed set since pollen is necessary for endosperm development. By contrast interspecific hybrids between apomictic taxa appear to be sexual and exhibit high pollen fertilities, probably due to an improved meiosis. Thus, apomixis leads to a decreased fertility inRubus, not the opposite, as often discussed.     

Treefall Gaps and Regeneration Composition in the Laurel Forest of Anaga (Tenerife): a Matter of Size?

The size of treefall gaps is an important determinant of regeneration composition in tropical and temperate forests. Preliminary studies in the laurel forest of Tenerife have shown that small gaps (<100 m²) were the most numerous. However, due to this small size, no significant differences were found between regeneration in gaps and regeneration below the canopy. Because infrequent large gaps (>100 m²) are present in the laurel forest, we analyzed the regeneration in these large uncommon gaps, considering their potentially important role in the dynamics of the system. Our main hypothesis is that large gaps are important disturbance to ensure the regeneration and stablishment of shade intolerant species. Only five gaps larger than 100 m² (ranging from 125–268 m²) were found in the study area. Data from a further 20 small gaps (<100 m²), analysed in a previous study, was also included. Control plots were examined close to the gaps in order to determine regeneration below the closed canopy. We did not find a significant difference between regeneration density in the gaps (<100 m²) and regeneration below the canopy in the control plots. Contrary to our expectations, regeneration was lower in the large gaps than under the canopy. The open canopy in the large gaps increases light intensity, and has a negative effect on the germination and growth of shade-tolerant tree species like Viburnum tinus (although non-statistically significant); however, the increase in light intensity is not sufficient to stimulate the germination of shade-intolerant tree species. The effects of treefall gaps in the dynamics of the laurel forest of Anaga should be not considered as significant in comparison to other factors such as human disturbances or infrequent disturbances (land slides or hurricanes).     

Evapotranspiration of tropical peat swamp forests

In Southeast Asia, peatland is widely distributed and has accumulated a massive amount of soil carbon, coexisting with peat swamp forest (PSF). The peatland, however, has been rapidly degraded by deforestation, fires, and drainage for the last two decades. Such disturbances change hydrological conditions, typically groundwater level (GWL), and accelerate oxidative peat decomposition. Evapotranspiration (ET) is a major determinant of GWL, whereas information on the ET of PSF is limited. Therefore, we measured ET using the eddy covariance technique for 4–6 years between 2002 and 2009, including El Niño and La Niña events, at three sites in Central Kalimantan, Indonesia. The sites were different in disturbance degree: a PSF with little drainage (UF), a heavily drained PSF (DF), and a drained burnt ex‐PSF (DB); GWL was significantly lowered at DF, especially in the dry season. The ET showed a clear seasonal variation with a peak in the mid‐dry season and a large decrease in the late dry season, mainly following seasonal variation in net radiation (R_n). The R_n drastically decreased with dense smoke from peat fires in the late dry season. Annual ET forced to close energy balance for 4 years was 1636 ± 53, 1553 ± 117, and 1374 ± 75 mm yr^?1 (mean ± 1 standard deviation), respectively, at UF, DF, and DB. The undrained PSF (UF) had high and rather stable annual ET, independently of El Niño and La Niña events, in comparison with other tropical rainforests. The minimum monthly‐mean GWL explained 80% of interannual variation in ET for the forest sites (UF and DF); the positive relationship between ET and GWL indicates that drainage by a canal decreased ET at DF through lowering GWL. In addition, ET was decreased by 16% at DB in comparison with UF chiefly because of vegetation loss through fires.     

Landscape patterns and their changes in Sichuan Ruoergai Wetland National Nature Reserve

In Sichuan Ruoergai Wetland National Nature Reserve, the changes in landscape patterns over a period of 17 years – from 1990 to 2007 – have been studied by means of RS, GIS technologies and field validation. In the reserve, the seven landscape patterns – river, lake, swamp, seasonal swamp, meadow, shrub and desert – were subject to the current study. The results show that the swamp, seasonal swamp, and meadow are the dominant landscape types occupying over 90% of the reserve’s total area. Over the past 17 years, the distribution area of swamp has been decreased by 3.81%, while that of seasonal swamp and meadow has been increased by 2.58% and 2.09%, respectively. In addition, the desert area has expanded by 1.19% since 2000. The nature reserve can be characterized by patch diversity, causing landscape fragmentation over the years; the total number of patches increased to 585 from 544 and the average area of the patches decreased to 283.49 h m² from 304.29 h m² – to the detriment of the wetland functions such as carbon sink and habitats for wild animals. In the study, the causes of the alternations are discussed as mainly resulting from climate change and human disturbances such as overgrazing, drainage, and unmanaged tourism. The study results provide a scientific basis at a strategic scale for the efficient conservation and management implementation of nature reserve zoning and assessment of landscape ecological functions and conservation values.     

The impact of insomnia and sleep disturbances on depression and suicidality.

Previous research has demonstrated an association between suicidality and sleep, suggesting that sleep disturbances may exacerbate mood dysregulation in participants suffering from mood disorders. The purpose of this study was to investigate the impact of sleep disturbances and insomnia on depression and suicidality in a nontreatment seeking sample of college students. Results indicated that insomnia and nightmares were significant predictors of symptoms of depression, while only nightmares significantly predicted suicidal ideation. Further analysis indicated that participants with elevated scores on insomnia, nightmares, or both experienced differing levels of depression and suicidal ideation. Future directions and treatment implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Compounded Perturbations Yield Ecological Surprises

All species have evolved in the presence of disturbance, and thus are in a sense matched to the recurrence pattern of the perturbations. Consequently, disturbances within the typical range, even at the extreme of that range as defined by large, infrequent disturbances (LIDs), usually result in little long-term change to the system's fundamental character. We argue that more serious ecological consequences result from compounded perturbations within the normative recovery time of the community in question. We consider both physically based disturbance (for example, storm, volcanic eruption, and forest fire) and biologically based disturbance of populations, such as overharvesting, invasion, and disease, and their interactions. Dispersal capability and measures of generation time or age to first reproduction of the species of interest seem to be the important metrics for scaling the size and frequency of disturbances among different types of ecosystems. We develop six scenarios that describe communities that have been subjected to multiple perturbations, either simultaneously or at a rate faster than the rate of recovery, and appear to have entered new domains or “ecological surprises.” In some cases, three or more disturbances seem to have been required to initiate the changed state. We argue that in a world of ever-more-pervasive anthropogenic impacts on natural communities coupled with the increasing certainty of global change, compounded perturbations and ecological surprises will become more common. Understanding these ecological synergisms will be basic to environmental management decisions of the 21st century. Received 14 July 1998; accepted 18 September 1998.