Climate change impoverishes and homogenizes ants’ community structure: a long term study

Climate change brings along trend-like changes as well as changes in the temporal variations in environmental conditions which interact with the biological dynamics of ecological systems. Therefore, only studies covering several decades may unveil long term trends in ecological systems, such as in animal communities. To demonstrate if recent climatic changes have caused fundamental changes in the structure of a key arthropod community, I studied the long-term dynamics of ant colonies for 37 years on a sandy grassland in central Hungary. To be able to monitor colonies – the natural units of ant communities – with the possible least disturbance, I applied two grids of a total of 80 slate plates as artificial nesting sites. Prior to the presented study, a well-defined spatial ant community structure had been identified in the studied habitat, which consisted of three species groups (dune top, transitional and dune slack groups), occupying different habitat patches. During the study period 2813 nests of 11 ant species were recorded under the slates. Over the 37 years, community pattern markedly changed, dune slack species disappeared from the studied plots, while the frequency of drought-tolerant dune top species increased by a significant trend. No significant trend was observed in the case of the transitional species group. On the species population level, two species, Lasius niger and Formica cunicularia, showed an intensive population decline; while the Plagiolepis taurica population significantly increased and spatially joined the transitional species group in the dune slack in the second half of the project. These changes led to a major decline in species richness and a homogenization of species composition across habitat patches. Multiple correlation analyses revealed that the depletion of groundwater had the strongest relationship with these population trends. The study indicates that climate change can be linked to a fundamental change in the community structure of major ecosystem actors

The Falling Incidence of Hematologic Cancer After Heart Transplantation

[Abstract] Background. A number of changes in the management of heart transplantation (HT) patients have each tended to reduce the risk of post-HT hematologic cancer, but little information is available concerning the overall effect on incidence in the HT population. Methods. Comparison of data from the Spanish Post-Heart-Transplantation Tumour Registry for the periods 1991–2000 and 2001–2010. Results. The incidence among patients who underwent HT in the latter period was about half that observed in the former, with a particularly marked improvement in regard to incidence more than five yr post-HT. Conclusions. Changes in HT patient management have jointly reduced the risk of hematologic cancer in the Spanish HT population. Long-term risk appears to have benefited more than short-term risk

Response of the photosynthetic apparatus to a flowering-inductive period by water stress in Citrus

The photosynthetic responses to a flowering-inductive water-stress period and recovery were studied and compared in two Citrus species. Under greenhouse conditions, Fino lemon and Owari satsuma trees were subjected to moderate (-2 MPa at predawn) and severe (-3 MPa) water stress levels and were re-watered after 60 days. Vegetative growth was inhibited during the stress assays, and strong defoliation levels were reported, especially in Fino lemon. In both species, bud sprouting was induced after re-watering. Flowers and vegetative shoots developed in Owari satsuma after a drought period, and the development was independent of the stress level. In Fino lemon, vegetative shoots and flowers were primarily formed after moderate and severe stress, respectively. The photosynthetic rate and stomatal conductance were reduced by water stress, and a marked increase in water-use efficiency at the moderate water deficit level was observed. Nevertheless, the photosynthetic apparatus was not damaged, since the maximum quantum yield, photosynthetic pigment concentrations and Rubisco level and activity did not change. Furthermore, the measured malonyldialdehyde (MDA) and peroxidase activity indicated that oxidative stress was not specifically triggered by water stress in our study. Therefore, the gas exchange, fluorescence and biochemical parameters suggested that diffusional limitations to photosynthesis predominated in both of the studied Citrus species, and explained the rapid recovery of the photosynthetic parameters after rehydration. The net CO 2 fixation rate and stomatal conductance were recovered within 24 h in Fino lemon, whereas 3 days were required in Owari satsuma. This suggests the presence of some metabolic limitations in the latter species. Furthermore, the sensibility of the defoliation rates, the accumulation of proline and the stomatal behaviour in response to water stress indicated a higher drought tolerance of Fino lemon, according to its better acclimation to hot climates. © 2011 Springer-Verlag.The authors thank Dr. J. Moreno and co-workers from the Departamento de Bioquimica of the Universidad de Valencia for his help and support in the Rubisco assays, and Dr. F. Fornes, Dr. A. Calatayud and Dr. E. Primo-Millo for the critical review of the manuscript. This work was funded by the Universitat Politecnica de Valencia, Spain (Ayudas para primeros proyectos de investigacion PAID06-06).Ávila Reséndiz, C.; Guardiola Barcena, JL.; González Nebauer, S. (2012). Response of the photosynthetic apparatus to a flowering-inductive period by water stress in Citrus. Trees - Structure and Function. 26(3):833-840. https://doi.org/10.1007/s00468-011-0657-4S833840263Addicott FT (1982) Abscission. 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Ecological conditions, flora and vegetation of a large doline in the Mecsek Mountains (South Hungary)

Vegetation-environment relationships were investigated in a large doline of the Mecsek Mts (South Hungary). To reveal the vegetation pattern, we collected vegetation data and environmental variables along a 243 m long transect. Atotal of 144 vascular plant species and 4 vegetation types were identified in the doline.We found that both the species composition and the vegetation pattern are significantly influenced by air temperature, air humidity, soil moisture and altitude. Our results confirm the putative temperature and vegetation inversion in the doline

Species composition and diversity of natural forest edges: edge responses and local edge species

Habitat boundaries in general and forest edges in particular belong to the central issues in ecology. Theories about community and environmental edge-responses are diverse, but there is a lack of sufficient supporting field evidence: no consensus exists about distinctness and diversity of edges, and the existence of edge-related species. Moreover, as most studies focus on man-made edges, natural forest edges are less understood. We studied xeric forest edges in a wooded-steppe area. Twelve forest patches were selected, and plots were set up within the edges, the forest interiors and the grasslands. Species composition, species richness and Shannon diversity were compared between the three habitat types as well as between differently oriented edges. We identified diagnostic species for all habitats. Local habitat preferences of the edge-related species were compared to their regional preferences. Environmental factors of the different habitats were assessed by using ecological indicator values. Forest edges differed both from forest interiors and grasslands, forming a narrow but distinct habitat type between them. Species composition of the edges was not simply a mixture of forest and grassland species, but there were several edge-related species, most of which are regionally regarded as typical of closed steppe grasslands. Neither shady conditions of the forests, nor dry conditions of the grasslands are tolerated by these species; this is why they are confined to edges. Species richness and Shannon-diversity were higher within edges than in either of the habitat interiors. Ecological indicator values suggested that light intensity and temperature were higher in the edges than in the forests, but were lower than in the grasslands. In contrast, soil moisture was lower in the edges than in the forests but was higher than in the grasslands. There were slight differences between differently exposed edges concerning species composition, species richness and Shannon diversity. We conclude that edges should be considered an integral part of wooded-steppes. Their high diversity may have nature conservation implications. Our study emphasizes that edge species may be confined to edges only locally, but may have a broader distributional range in other areas. These species may be referred to as local edge species. Our results also point out that the very same edge can be interactive and non-interactive at the same time, depending on the characteristics considered

Comparison between multiplex PCR and phenotypic systems for Candida spp. identification.

This study evaluated the performances of three phenotypic systems (RapID Yeast panel, Vitek2 YST card, and API 20 C AUX) and multiplex PCR for Candida spp. identification. Four-hundred and fifty clinical strains of Candida spp. were identified with the four systems and results of multiplex PCR were compared with those of phenotypic methods. The best correspondence was obtained between Multiplex PCR and API 20 C AUX (83.7%), but the other comparisons showed similar values (81.7% and 79.3% for Vitek2 and RapID Yeast panel respectively). The correspondence was lower for all the methods in identification of C. krusei; this may be of concern in addition to the azole resistance and the often endogenous origin of this yeast. In the comparison with the three phenotypic methods, multiplex PCR could be reliable and time-saving in the identification of Candida spp. for diagnostics purposes. Nowadays, a large variety of both traditional and molecular methods for Candida spp. identification are commercially available. Multiplex PCR applied in this study may be more rapid and sensitive than phenotypic systems, and less expensive than other molecular methods