10-Years Land Use Changes Decrease Landscape Integrity in a Brazilian Hydrographic Basin

Changes in land use associated with the suppression of native vegetation can greatly alter the landscape configuration, affecting biodiversity and environmental services availability. This study analyzes how changes in land use affect landscape patterns of vegetation remnant over a 10 year period. We quantified spatial landscape patterns throughout a hydrographic basin for the years 2002, 2008, 2010 and 2012, using nine landscape metrics. An indicator of integrity was used to details the transformation processes occurring in the basin that could be used to monitor the impact of landscape changes and its spatial patterning. Results showed that over this decade, extension of farming activities reduced the cover of native vegetation by 4.4%, with grassy-woody savanna, wooded savanna and forested savanna impacted especially strongly. Suppression of vegetation across this period reduced the size of fragments and their connectivity. The landscape fragmentation indicator indicated that the fragmentation pattern varied spatially, with the upland areas along river headwaters, being most fragmented. Areas of floodplains vegetation, belonged to the Pantanal Wetland, although in better integrity states, are the most threatened by current pressures of land use change. An intense recovery program for headwaters and aquifer recharge areas, as well as riparian forests, is recommended to avoid the future depletion of water production. Besides, we also recommend the maintenance and recovering of the connectivity of the current remaining patches of natural vegetation corridors and elaboration of specific laws that incoporate the consolidated scientific knowladge about wetland ecosystem functioning, like the Pantanal.

Mid and late Holocene forest fires and deforestation in the subalpine belt of the Iberian range,northern Spain

The conversion of subalpine forests into grasslands for pastoral use is a well-knownphenomenon, although for most mountain areas the timing of deforestation has not been determined. The presence of charcoal fragments in soil profiles affected by shallow landsliding enabled us to date the occurrence of fires and the periods of conversion ofsubalpine forest into grasslands in the Urbión Mountains, Iberian Range, Spain. We found that the treeline in the highest parts of the northwestern massifs of the Iberian Range(the Urbión, Demanda, Neila, and Cebollera massifs) is currently between 1500 and 1600 m a.s.l., probably because of pastoral use of the subalpine belt, whereas in the past it would have reached almost the highest divides(at approximately 2100–2200 m a.s.l.). The radiocarbon dates obtained indicate that the transformation of the subalpine belt occurred during the Late Neolithic, Chalcolithic, Bronze Age, Iron Age, and Middle Ages. Forest clearing was probably moderate during fires prior to the Middle Ages, as the small size of the sheep herds and the local character of the markets only required small clearings, and therefore more limited fires. Thus, it is likely that the forest recovered burnt areas in a few decades; this suggests the management of the forest and grasslands following a slash-andburn system. During the Middle and Modern Ages deforestation and grassland expansion affected most of the subalpine belt and coincided with the increasing prevalence of transhumance, as occurred in other mountains in the Iberian Peninsula(particularly the Pyrenees). Although the occurrence of shallow landslides following deforestation between the Neolithic and the Roman Period cannot be ruled out, the most extensive shallow landsliding processes would have occurred from the Middle Ages until recent times.

The Pattern of Sediment Dispersion in the Front Sector of the Stenhouse and Ajax Glaciers, Visca Anchorage, King George Island, Antarctica

This study investigated the dispersal pattern of suspended sediment in the areas near the Stenhouse and Ajax glaciers, Visca Anchorage, Martel Inlet, King George Island, Antarctica. This study was conducted using visible band processing of Quickbird high-resolution spatial images obtained in October 2006. The methodology was also based on the collection and interpretation of data obtained from water samples collected in Admiralty Bay in December 2004. The digital processing of satellite images was performed using a classification method based on the reflectance characteristics of water. The classified images improved visual identification of the dispersion pattern of suspended sediments in the study area. These data were related to the interpretation of analyses conducted on suspended particulate matter (SPM) in the water. The sediment dispersal pattern observed may be associated with glacial erosion processes, their input of meltwater from the front of the glaciers into the study area, detritus flow processes and glaciomarine circulation in the region.

What physical habitat factors determine the distribution of gastropods in neotropical headwater streams?

Freshwater gastropods play a pivotal role in the structure and functioning of freshwater ecosystems,but despite their importance,there are still gaps in their ecology.Our goal was to understand what physical habitat factors are the most important for the distribution of freshwater gastropods in headwater stream ecosystems in the Neotropical Savanna and provide a baseline for conservation and management efforts for freshwater gastropods in this biome.We identified five taxa,each with different environmental prefferences.Littoridina presence related negatively with stream slope,Biomphalaria presence related positively with total dissolved solids and the proportions of cobble,fine sediment and organic matter.Gundlachia presence correlated positively with elevation and the proportion of pools in the site.Physa presence related negatively with total dissolved solids and positively with alkalinity.Melanoides tuberculata presence correlated positively with the proportion of coarse gravel.Our results highlight the challenge for protecting native freshwater gastropod assemblages(and managing non-native invasive species),because environmental preferences vary widely amongst taxa and most are vulnerable to common anthropogenic disturbances.

Assemblage-based biomonitoring of freshwater ecosystem health via multimetric indices:A critical review and suggestions for improving their applicability

Freshwater biota are more comprehensive and direct indicators of biological impacts,and more meaningful to the public than water quality or physical habitat surrogates.Freshwater biotic data and the multiple biological indicators developed from them offer a much richer array of data for assessing the impacts of pollution controls than a limited set of physical or chemical measures.In recent decades,assemblage-based assessments by ecologists,environmental scientists,and water quality agencies have been employed globally for determining the condition of,and threats to,freshwater ecosystems.A key step in this advance has been the development of multimetric indices(MMIs)or indices of biotic integrity(IBIs)based on quantitative assessments of algae,macrophyte,macroinvertebrate,fish or riparian bird assemblages.In Europe,where biological assemblages are mandated for assessing freshwater ecosystem health,many indices are multimetric.However,the proliferation of MMIs globally has not always occurred through the application of rigorous study designs and monitoring protocols,nor have they always effectively incorporated functional metrics,stressor assessments,and statistical analyses.Therefore,in this review,we discuss eleven major concerns with the development and application(including logistical limitations)of multimetric indicators based on freshwater biota to encourage more rigorous and widely applicable(transferable)MMI use and implementation.Specifically,our concerns focus on reference conditions;sampling effort,methods,and season;trophic guild definition;metric comprehensiveness,options,screening and scoring;and MMI validation.MMIs could also benefit from increased attention to ecological mechanisms and metric development,to further improve our understanding of anthropogenic impacts as well as rehabilitation effects on freshwater ecosystems globally.Paying closer attention to study designs,ecological mechanisms and metric development should further improve our understanding of anthropogenic impacts and better facilitate rehabilitation of degraded freshwater ecosystems,as well as aiding in the conservation of healthy freshwater ecosystems globally.