In tropical rainforests environmental conditions vary dramatically from the ground to the canopy, resulting in a marked stratification in the way vertical space is used by organisms, but research ...work is often limited to the understorey layer. Aerial insectivorous bats are a highly diverse group that plays key roles in the ecology of rainforests, but their use of vertical space remains elusive.
Using automatic ultrasound recording stations placed in the canopy, subcanopy and understorey we tested if bat activity and species diversity are vertically stratified, both in the forest interior and near the edges of water bodies. These patterns were tested separately for individual species, and for two functional groups – open space and edge space bats.
Insectivorous bat activity increased by roughly seven fold, and species diversity doubled, from the understorey to the canopy. Both edge space and open space bats were more active in the upper strata, but this tendency was much more accentuated in the latter. Myotis riparius was the only species with greater activity near the understorey. These patterns were altered at the edges of water bodies, where vertical stratification was much less marked.
The observed patterns are parsimoniously explained by constraints imposed by vegetation clutter that change across strata, which affect bat species differently. Only bats better adapted to closed spaces are usually capable of foraging within the understorey, whereas the majority of species can exploit the free spaces immediately below the canopy; open space bats seem to concentrate their activity above the canopy. This importance of the inter strata open spaces for bat foraging highlights the need to preserve pristine stratified rainforests, as even selective logging usually disrupts vertical stratification. Moreover, the concentration of insectivorous bats at the upper strata of rainforests underlines the need to include canopy level sampling in ecological studies.
Although locating wildlife roadkill hotspots is essential to mitigate road impacts, the influence of study design on hotspot identification remains uncertain. We evaluated how sampling frequency ...affects the accuracy of hotspot identification, using a dataset of vertebrate roadkills (n = 4427) recorded over a year of daily surveys along 37 km of roads. “True” hotspots were identified using this baseline dataset, as the 500-m segments where the number of road-killed vertebrates exceeded the upper 95% confidence limit of the mean, assuming a Poisson distribution of road-kills per segment. “Estimated” hotspots were identified likewise, using datasets representing progressively lower sampling frequencies, which were produced by extracting data from the baseline dataset at appropriate time intervals (1–30 days). Overall, 24.3% of segments were “true” hotspots, concentrating 40.4% of roadkills. For different groups, “true” hotspots accounted from 6.8% (bats) to 29.7% (small birds) of road segments, concentrating from <40% (frogs and toads, snakes) to >60% (lizards, lagomorphs, carnivores) of roadkills. Spatial congruence between “true” and “estimated” hotspots declined rapidly with increasing time interval between surveys, due primarily to increasing false negatives (i.e., missing “true” hotspots). There were also false positives (i.e., wrong “estimated” hotspots), particularly at low sampling frequencies. Spatial accuracy decay with increasing time interval between surveys was higher for smaller-bodied (amphibians, reptiles, small birds, small mammals) than for larger-bodied species (birds of prey, hedgehogs, lagomorphs, carnivores). Results suggest that widely used surveys at weekly or longer intervals may produce poor estimates of roadkill hotspots, particularly for small-bodied species. Surveying daily or at two-day intervals may be required to achieve high accuracy in hotspot identification for multiple species.
•Sampling frequency strongly affects roadkill hotspot identification.•Hotspot spatial accuracy declines rapidly with increasing interval between surveys.•Missing true hotspots is the main source of error.•Hotspot accuracy is lower for small-bodied species.•Widely used study designs may provide inaccurate hotspots.
Recent studies suggest that roads can significantly impact bat populations. Though bats are one of the most threatened groups of European vertebrates, studies aiming to quantify bat mortality and ...determine the main factors driving it remain scarce. Between March 16 and October 31 of 2009, we surveyed road-killed bats daily along a 51-km-long transect that incorporates different types of roads in southern Portugal. We found 154 road-killed bats of 11 species. The two most common species in the study area,
Pipistrellus kuhlii
and
P. pygmaeus
, were also the most commonly identified road-kill, representing 72 % of the total specimens collected. About two-thirds of the total mortality occurred between mid July and late September, peaking in the second half of August. We also recorded casualties of threatened and rare species, including
Miniopterus schreibersii
,
Rhinolophus ferrumequinum
,
R. hipposideros
,
Barbastella barbastellus
, and
Nyctalus leisleri
. These species were found mostly in early autumn, corresponding to the mating and swarming periods. Landscape features were the most important variable subset for explaining bat casualties. Road stretches crossing or in the vicinity of high-quality habitats for bats—including dense Mediterranean woodland (“montado”) areas, water courses with riparian gallery, and water reservoirs—yielded a significantly higher number of casualties. Additionally, more road-killed bats were recorded on high-traffic road stretches with viaducts, in areas of higher bat activity and near known roosts.
Chagas disease, caused by Trypanosoma cruzi, is a devastating parasitic infection affecting millions of people. Although many efforts have been made for the development of immunotherapies, there is ...no available vaccine against this deadly infection. One major hurdle for the rational approach to develop a T. cruzi vaccine is the limited information about the proteins produced by different phylogenetic lineages, strains, and stages of the parasite. Here, we have adapted a 1D nanoHPLC system to perform online 2D LC–MS/MS, using the autosampler to inject the eluting salt solutions in the first dimension separation. The application of this methodology for the proteomic analysis of the infective trypomastigote stage of T. cruzi led to the identification of 1448 nonredundant proteins. Furthermore, about 14% of the identified sequences comprise surface proteins, most of them glycosylphosphatidylinositol (GPI)-anchored and related to parasite pathogenesis. Immunoinformatic analysis revealed thousands of potential peptides with predicted high-binding affinity for major histocompatibility complex (MHC) class I and II molecules. The high diversity of proteins expressed on the trypomastigote surface may have many implications for host-cell invasion and immunoevasion mechanisms triggered by the parasite. Finally, we performed a rational approach to filter potential T-cell epitopes that could be further tested and validated for development of a Chagas disease vaccine.
Temperature-independent strain and angle measurements are achieved resorting to a taper fabricated on a Bragg fiber using a CO 2 laser. The characteristic bimodal interference of an untapered Bragg ...fiber is rendered multimode after taper fabrication and the resulting transmission spectra are analyzed as a function of strain, applied angle, and temperature variations. The intrinsic strain sensitivity exhibited by the Bragg fiber is increased 15 fold after tapering and reaches 22.68 pm/με. The angle and temperature measurements are also performed with maximum sensitivities of 185.10 pm/deg and -12.20 pm/K, respectively. The difference in wavelength shift promoted by variations in strain, angle, and temperature for the two fringes studied is examined. Strain and angle sensing with little temperature sensitivity is achieved, presenting a response of 2.87 pm/με and -57.31 pm/deg, respectively, for strain values up to 400 με and angles up to 10°. Simultaneous angle and strain measurements are demonstrated.
A new family of eight ruthenium(II)-cyclopentadienyl bipyridine derivatives, bearing nitrogen, sulfur, phosphorous and carbonyl sigma bonded coligands, has been synthesized. Compounds bearing ...nitrogen bonded coligands were found to be unstable in aqueous solution, while the others presented appropriate stabilities for the biologic assays and pursued for determination of IC50 values in ovarian (A2780) and breast (MCF7 and MDAMB231) human cancer cell lines. These studies were also carried out for the 5: HSA and 6: HSA adducts (HSA=human serum albumin) and a better performance was found for the first case. Spectroscopic, electrochemical studies by cyclic voltammetry and density functional theory calculations allowed us to get some understanding on the electronic flow directions within the molecules and to find a possible clue concerning the structural features of coligands that can activate bipyridyl ligands toward an increased cytotoxic effect. X-ray structure analysis of compound Ru(η5-C5H5)(bipy)(PPh3)PF6 (7; bipy=bipyridine) showed crystallization on C2/c space group with two enantiomers of the Ru(η5-C5H5)(bipy)(PPh3)+ cation complex in the racemic crystal packing.
New family of Ru(η5-C5H5)(bipyridine)(L)PF6 complexes shows that ‘L’ plays an important role in electronic activation of the bipyridine. The best cytotoxic effect was observed for the best electronic activation of this ligand. Display omitted
•New family of Ru(η5-C5H5)(bipyridine)(L)PF6 complexes•Structure–activity correlations drawn by spectroscopic, electrochemical and DFT data•‘L’ has a crucial role in the fine-tuning of the electronic density at Ru center.•Best cytotoxic effect in human cancer cells found for the best electronic activation of bipyridine
•Insectivorous birds can provide biological control services in vineyards.•Functional diversity indices may be potential indicators of biocontrol by birds.•Vineyards were grouped in three types in ...our case-study.•Functional diversity indices (and potential biocontrol) varied among vineyard types.•Smaller, heterogeneous vineyards with nearby woodlands may have higher biocontrol.
Insectivorous birds have a large potential to provide biocontrol services in vineyards, thus contributing to the sustainability of this agroecosystem. Bird communities are influenced by vineyard management practices and surrounding landscape, which may influence their role as ecosystem service providers. Functional diversity indices are indicators of bird community composition, and thus may reflect potential biocontrol services. We surveyed 31 vineyard plots in southern Portugal to assess vineyard characteristics (management intensity and landscape context) that may influence functional insectivorous birds in vineyards, using seven functional diversity indices as potential biocontrol indicators. We used eight characteristics of vineyard plots to define three vineyard types for our case-study: TREE – smaller vineyard plots surround by a more diverse landscape, with larger proportion of tree-habitats; AGRI – vineyard plots with medium size and greater cover by herbaceous vegetation, mostly surrounded by agricultural habitats (pastureland, crops); and VINE – vineyard plots of larger size and higher inter-row herbaceous vegetation, often surrounded by other vineyard plots. Five potential biocontrol indicators seemed to vary according to vineyard type. The richness of functional insectivorous birds, functional dispersion, functional richness, and Rao's functional diversity were all higher in vineyard TREE type compared to both AGRI and VINE types. The functional divergence was higher in vineyard TREE type than in VINE type, but similar to AGRI type. Accordingly, TREE type vineyards hold bird communities with more diverse and widespread ecological functions. This implies that smaller vineyard plots, in more heterogeneous landscapes, with neighbouring woodlands seem to have a higher potential of biocontrol services provided by insectivorous birds as suggested by using functional diversity indices as indicators.
We examined seasonal patterns of spatial variation in understory bird assemblages across a mosaic of upland and floodplain forests in central Amazonia, where variation in flooding patterns and ...floodwater nutrient load shapes a marked spatial heterogeneity in forest structure and composition. Despite great differences in productivity due to flooding by either nutrient-rich “white waters” (várzea) or nutrient-poor “black waters” (igapó), bird assemblages in the two floodplain forest types were relatively similar, showing lower abundances than adjacent upland forests (terra firme) and sharing a set of species that were absent or scarce elsewhere. Species that breed in pensile nests overhanging water were abundant in floodplain forests, whereas species that feed on the ground were generally scarce. Flooding affected assemblage dynamics in floodplain forests, with some influx of ground-dwelling species such as ant-following birds from adjacent upland during the low-water season, and the occupation by riverine and aquatic species such as kingfishers during floods. Spatial configuration influenced the seasonal pattern of assemblage structuring, with movements from terra firme occurring primarily to adjacent igapó forests. No such influx was detected in várzea forests that were farther from terra firme and isolated by wide river channels. Results support the view that habitat heterogeneity created by flooding strongly contributes to maintain diverse vertebrate assemblages in Amazonia forest landscapes, even in the case of largely sedentary species such as understory forest birds. Including both upland and floodplain forests in Amazonia reserves may thus be essential to preserve bird diversity at the landscape scale.
•Cork oak forests are declining across Southwestern Europe.•We assessed the incidence of canopy insect pests in cork oaks agroforests.•Most insect pests benefited with agroforestry ...intensification.•Diversification of tree species and ages may contribute to reduce oak pest impacts.
The decline of oak (Quercus spp.) forests is a current trend in Northern Hemisphere and is characterized by a loss in tree vigour and increased mortality. The canopy insects are suspected to have role in this decline, but there is poor knowledge about their incidence in evergreen-oak stands. The main aim of this study is to characterize the incidence of main insect groups affecting branches and leaves of an evergreen-oak species (the cork oak Quercus suber) and evaluate which management practices and environmental traits of agroforestry systems affect it. In the spring/summer of 2018, we measured the incidence of attacks on branches and leaves by gall-makers (Diptera, Cecidomyiidae), blade-miners (Lepidoptera and Coleoptera), midrib-miners (Lepidoptera, Heliozelidae), chewer caterpillars (Lepidoptera), chewer sawflies (Hymenoptera, Tenthredinidae), weevils (Coleoptera, Curculionidae) and branch-borers (Coleoptera, Buprestidae). We analysed the frequency of pest signs according to different indicators: management practices, tree maturity, forest diversity, forest fragmentation, and latitude and longitude. The most frequent signs of insect pests on tree leaves corresponded to blade-miners, midrib-miners, chewer caterpillars and chewer sawflies. With exception of midrib-miners and branch-borers, all insect pests were found on cork oak stands experiencing decline and benefited from management intensification. Our study suggests that a diverse-aged stand may reduce the frequency of midrib-miners and chewer caterpillars, as well the attack of branch-borers. Moreover, a high plant diversity in forests can contribute to reduce the impact of defoliators on cork oaks (e.g., chewer sawflies) and understory reduction decreased the exposure of trees to gall-makers. Moreover, we found that forest fragmentation may increase the frequency of blade-miners and chewer caterpillars. We conclude that insect pests have a high incidence in cork oak stands and thus, may have and important role in its decline. Considering that a high frequency of pests is often associated with increased management intensity, a change to a more sustainable use of these systems is urgently needed.
A new family of “RuCp” (Cp=η5-C5H5) derivatives with bidentate N,O and N,N′-heteroaromatic ligands revealed outstanding cytotoxic properties against several human cell lines namely, A2780, A2780CisR, ...HT29, MCF7, MDAMB231, and PC3. IC50 values were much lower than those found for cisplatin. Crystal structure of compound 4 was determined by X-ray diffraction studies. Density functional theory (DFT) calculations performed for compound 1 showed electronic flow from the ruthenium center to the coordinated bidentate ligand, in agreement with the electrochemical studies and the existence of a metal-to-ligand charge-transfer (MLCT) band evidenced by spectroscopic data.
New “RuCp” derivatives containing bidentate heteroaromatic ligands were fully characterized; outstanding cytotoxicity was found for several human cell lines. Display omitted
► New family of “RuCp” derivatives containing bidentate heteroaromatic ligands. ► Spectroscopic results showed MLCT band. ► DFT calculations corroborate π backdonation suggested by experimental data. ► Outstanding cytotoxic properties against several human cancer cell lines. ► Reversibility of Ru(II)/Ru(III) shows the interest as bioreductive prodrugs.
PDF
