Natureza & Conservacao最新文献

We aimed to evaluate the role of spatial units with different shapes and sizes on road-kill modeling for small vertebrate species. We used the road-kill records of two reptiles, water snake (Helicops infrataeniatus) and D’Orbigny's slider turtle (Trachemys dorbigni), and three mammals, white-eared opossum (Didelphis albiventris), coypu (Myocastor coypus) and Molina's Hog-nosed skunk (Conepatus chinga). Hierarchical partitioning was used to evaluate the independent influence of different land-use classes on road-kill by varying the shape and size of the spatial units. Variables that most explained road-kill were consistent over the different spatial unit types. The standard size seemed to be a reasonable solution for these species. Prior analysis with several sizes and shapes is needed to identify the appropriate spatial unit to model road-kill occurrence for larger vertebrates with different history traits.

Ramos and Anjos (2014) worked with birds in two riparian “forests” from the northwest of the state of Paraná, southern Brazil, to evaluate how the width and biotic integrity of the “forests” affected the communities. One of their conclusions was that riparian forest should be expanded to a minimum of 50 m of width on each side of a stream. I believe that Ramos and Anjos (2014) compared different environments with different sampling areas: one sampled area was covered by secondary vegetation, which has so far not reached the forest stage, and showed approximately 40% less arboreal vegetation than the second sampled area. This undermines some of the claims made by Ramos and Anjos (2014), for example that the riparian vegetation should be expanded to a minimum of 50 m. The minimum width of the riparian forests must be better evaluated comparing samples of vegetation at similar regeneration stages.

Because of changes in riparian zones and water properties, human disturbances in terrestrial ecosystems can affect the decomposition of organic matter and invertebrate assemblages in forest streams. The aim of this study was to evaluate how changes in the riparian zones influenced leaf breakdown rates and colonization by invertebrate shredders. Leaves of Miconia chartacea were incubated in four streams of the same watershed that presented different conservation levels in the riparian zones. Leaf breakdown rates were higher in the presence of shredders and in the most preserved stream. In terms of abundance and biomass, shredders differed among streams, and the importance of these organisms on leaf decomposition decreased in altered streams. These results suggest the conservation level in the riparian zones influenced leaf decomposition mediated by shredders, and the observed decrease in breakdown rates was probably due to the high sensitivity of shredders to changes in the availability of food resources and habitat.

Land degradation is a complex concept that integrates different aspects, including changes in soil conditions, biodiversity, productivity and socio-economic implications, compared to a reference state. We propose a new conceptual framework to analyze degradation stages and restoration thresholds in species-rich natural grasslands. The framework integrates different degradation stages with their respective thresholds and describes key processes of land-use change that lead to certain stages and thresholds. Specifically, we discuss two scenarios of grassland degradation, i.e. unsuitable grassland management and complete change of land use, sometimes followed by spontaneous recovery. We illustrate the framework with the case of south Brazilian grasslands, which are rich in biodiversity, but suffer from a series of degradation processes and are poorly considered from a conservation perspective. The conceptual framework can be applied by studies on degradation and restorability of tropical and subtropical grasslands after changes in management or transition to other land use; it will facilitate decisions on alternative management and conservation.

Ecosystem services are the benefits that natural environments supply to human beings. Due to the immense diversity of ecosystems and objectives for which their services are being assessed, there are no standard methodologies for this type of evaluation. The high biodiversity and geodiversity of the coastal zone allow a wide range of services. However, deleterious impacts to the environment threaten the delivery of these services and, consequently, the human well-being they lead to. The coastal zone, with its multiple users and impacts, is a case in which an ecosystem-based approach would bring many benefits within the scope of an integrated coastal management strategy. By considering the ecosystem services supplied by the coastal zone, it is possible to make well-informed decisions. The objective of the present study was to carry out a revision on ecosystem services and their application within the context of coastal management.

Ecological investigations are increasingly using functional diversity in order to understand different patterns, such as species occurrence, species competitive abilities, and the influence of biological communities on ecosystem functioning. Here we provide an overview of the history and applicability of functional diversity in ecological studies. We found that the idea of functional diversity emerged many times and in distinct fields over the years. Functional diversity was conceived as an alternative classification to measure the ecological importance of species in a community, as well as a way to understand how biodiversity affects specific ecosystem functions. Gradually, new questions regarding functional traits emerged. Some examples include understanding species competitive abilities, patterns of species co-occurrence, community assembly, and the role of different traits on ecosystem functioning. The increasing use of functional-based approaches fueled the search for new metrics aiming at accurately estimating functional diversity and, consequently, categorical-based classifications of functional traits have been gradually replaced by continuous multi-trait approaches. More recently, the role of functional diversity was recognized as a key factor to maintain important functions and services of ecosystems. We present empirical evidence supporting this statement.