Authors:R. Cielo Filho, F.R. Martins, and A. Gneri
Hill, J.K. and K.C. Hamer. 1998. Using species abundance models as indicators of habitat disturbance in tropical forests. J. Appl. Ecol. 35: 458-460.
Using species abundance models as indicators of habitat disturbance in
Authors:K. Kenderes, R. Aszalós, J. Ruff, Zs. Barton, and T. Standovár
Angelstam, P. 2002. Reconciling the linkages of land management with natural disturbance regimes to maintain forest biodiversity in Europe. In: J. A. Bissonette and I. Storch (eds.),
Landscape Ecology and
Authors:E. A. Franceschi, E. A. Franceschi, P. S. Torres, P. S. Torres, D. E. Prado, D. E. Prado, J. P. Lewis, and J. P. Lewis
: Disturbances regimes and vegetation dynamics: role of floods in riverine wetlands. J.Veg. Sci. 7 :615-622.
Disturbances regimes and vegetation dynamics: role of floods in riverine wetlands
Pentoxifylline (PTX, a methylxanthine derivative) has been found to interrupt early gene activation for tumour necrosis factor, interleukin-1, interleukin-6 and tissue factor production and to improve survival from experimental sepsis. During endotoxaemia, lipopolysaccharide (LPS, endotoxin) and proinflammatory cytokines trigger the development of disseminated intravascular coagulation (DIC) via the tissue factor-dependent pathway of coagulation. The present study was undertaken to determine whether pentoxifylline could prevent coagulation disturbances in LPS-treated rabbits. Endotoxaemia was induced with E. coli lipopolysaccharide in New Zealand White rabbits. Forty rabbits were used and divided into four equal groups. Group 1 served as a control group; Group 2: lipopolysaccharide was injected intravenously, Group 3: pentoxifylline was injected intraperitoneally, Group 4: lipopolysaccharide and pentoxifylline were injected simultaneously. Blood samples were collected 6 h after the treatments. In rabbits with endotoxin-induced DIC, platelet count, leukocyte count, percentage of differential leukocyte values, fibrinogen level, antithrombin III (AT-III) and protein C (PC) activity were decreased. Moreover, activated partial thromboplastin time (APTT) and prothrombin time (PT) were prolonged when compared to the control group. In conclusion, haemostatic disturbances associated with endotoxin-induced DIC were moderately suppressed by the administration of PTX.
Authors:Birute Kazbariene, Aurelija Krikstaponiene, and Elena Monceviciute-Eringiene
Environmental pollution and consumption of alcohol evoke various immunomodulations promoting the progress of different pathologies. The purpose of this study was to evaluate the influence of alcohol consumption intensity on the immune system functions of humans living in ecologically different regions, i.e. in a district polluted with industrial siftings (Trakai, n=270) and in a relatively clean district (Širvintos, n=250). In the Trakai cohort 96% and in Širvintos group 89% of persons consumed alcohol. With regard to alcohol consumption habits the immunohaematological indices were investigated in the following four groups: abstinents, light alcohol users, moderate alcohol users and alcohol abusers. We determined the compensatory mechanisms of immune system functions of moderate alcohol users and alcohol abusers in comparison with abstinents in the relatively clean Širvintos district. In the Trakai district polluted with industrial siftings such compensatory reactions where not found. Thus, damage to the immune system functions is not only an endogenous risk factor for many diseases, but also an indicator of organism injury. This investigation stated, that immunity disturbance in humans depends on alcohol consumption intensity and place of residence.
classification: from general groups to specific groups based on response to disturbance. Trends Ecol. Evol. 12: 474-478.
Plant functional classification: from general groups to specific groups based on response to disturbance
Authors:C. Battisti, G. Fanelli, D. Pavel, L. Redolfi De Zan, S. Rossi de Gasperis, and G. Caneva
We tested the application of the concept of hemeroby and generalism at community level, on a set of birds occurring in various habitats of central Italy characterized by different level of disturbance. In each habitat-related bird community, we applied the recently published species-specific score in hemeroby (a proxy of habitat-related disturbance; HSi) and hemerobiotic diversity (a proxy of generalism; H’Hi) to local species frequency, obtaining weighted values at community level (HStot and H’Htot). The relationship between HStot vs. H’Htot showed an increasing trend moving from reed beds through forests and mosaics to urban communities. Quadratic model (best fit) evidenced a significant correlation between these variables and a tendency toward a hump-shaped curve, corroborating results already observed at species level (intermediate generalism hypothesis). The co-inertia analysis discriminated four groups of habitat-related communities, characterized by species with different levels of disturbance-sensitivity (expressed by HSi) and generalism (expressed by hemerobiotic diversity; H’Hi): (i) forest type-related, where mature wood communities were separated from a coppiced wood one; (ii) communities of moderately disturbed agricultural habitats; (iii) communities embedded in highly disturbed mosaics, and (iv) a group including either a highly disturbed urban habitat or a low disturbed wetland reed bed, with highly specialized species (respectively, synanthropic species and water-related species). Total scores in hemeroby and hemerobiotic diversity, expressing the composition in species with different disturbance preference and generalism, might act as good community-based indicators of degree of naturalness, especially for forest habitat types.
To clarify the relationship between the detritivore fiddler crab, Uca thayeri, and sediment bacteria, we quantified morphotype richness, abundance and evenness of these microorganisms inside the crabs’ guts and in mangrove-associated sediments in Sisal, México (21° 9′ N, 90° 1′ W) from July to September 2008. Increased bacterial richness and abundance were observed in mesocosm experiments when nutrients were added to the sediment or in the absence of fiddler crabs. Thus, crab disturbance seems to play a role in shaping the bacterial assemblage by reducing richness and abundance just as nutrient limitation does. Crabs can also play a second role by harboring a subset of bacterial morphotypes inside their gut. We exposed sterile sediment to fiddler crabs and found that viable cells were expelled from the crab’s gut and proliferated in previously sterile substratum. The bacterial community is thus structured by the foraging behavior of fiddler crabs since it benefits some bacteria and restricts others. By agar plating we have obtained conservative results, yet the data suggest that the crab influences the bacterial assemblage in two ways by allowing inoculation of the sand from the gut and reducing bacteria diversity through disturbance when foraging on sediments.
A szexuális diszfunkciók patogenezisében kiemelkedő jelentőségűek a kognitív organizáció zavarai, amelyek mint sajátos jelentésadási módozatok alakítják az egyén szexuális öndefinícióját, továbbá közvetítő szerepük van a fiziológiai, affektív és viselkedéses válaszok létrejöttében. A szexuális információfeldolgozás folyamatában mind a kultúra által közvetített szexuális forgatókönyvek és mítoszok, mind a diszfunkcionális szexuális attitűdök, sémák és modalitások aktiválódása kitüntetett szerepet játszik.
Authors:S. White, E. Bork, J. Karst, and J. Cahill
Similarity between seed bank and aboveground vegetation is frequently studied in order to better understand how community composition is affected by factors such as disturbance and succession. Grassland plant communities are known to be sensitive to shifts in precipitation and increases in temperature associated with climate change, but we do not know if and how these factors interact to affect the similarity between seed bank and aboveground vegetation. Also unknown is how the impact of grazing, the dominant land-use in grasslands, will interact with climatic conditions to affect similarity. We manipulated precipitation and temperature, and cut vegetation (as a proxy for grazing) at a grassland site for three years. Percent cover of aboveground vegetation was estimated in the third year, and compared with persistent seed bank samples taken in the year prior from the same plots. Similarity increased with reduced precipitation, was unresponsive to warming, and decreased with clipping. The aboveground community responded strongly to the treatments, while the seed bank community did less so, suggesting similarity responses were largely driven by changes in aboveground vegetation. Because of the importance of the seed bank in vegetation regeneration, understanding the relationship between seed bank and aboveground vegetation will improve our understanding of plant community dynamics under climate change and varied management (grazing) intensities.