a1_Based on light and scanning electron microscopical studies, eight species (five adult and three larval) of nematodes belonging to the Ascaridida, Oxyurida and Enoplida were collected from fishes of the Okavango River, Botswana, namely Falcaustra similis Moravec et Van As, 2004, Atractidae gen. sp. (only female) (both Cosmocercoidea), Cucullanus sp. (only female) (Seuratoidea), Cithariniella longicaudata sp. n., Synodontisia annulata sp. n. (both Oxyuroidea), Contracaecum sp. third-stage larvae, third-stage larvae of Galeiceps sp. (both Ascaridoidea) and Eustrongylides sp. fourth-stage larvae (Dioctophymatoidea). The new species Citharinella longicaudata (type host Schilbe intermedius Rüppel) is mainly characterised by the shape and size of cephalic papillae and the spicule 108 µm long, and Synodontisia annulata (type host S. intermedius) by the shape of cephalic papillae, body length of gravid females (4.88-5.33 mm) and a short spicule (66 µm long). The female specimen of Cucullanus sp. from Tilapia sparmanni Smith markedly differs from congeners parasitising inland fishes in Africa by the elongate pseudobuccal capsule and by the excretory pore far posterior to the oesophago-intestinal junction; apparently, it belongs to an undescribed species. Galeiceps larvae parasitising fishes are described for the first time. Cithariniella gonzalezi Van Waerebeke, Chabaud, Bain et Georges, 1988 is considered a junior synonym of C. khalili Petter, Vassiliadès et Troncy, 1972, and the previous records of Cithariniella citharini Khalil, 1964 from Synodontis spp. in Egypt concern, in fact, Cithariniella khalili Petter, Vassiliadès et Troncy, 1972., a2_The specimens of Cithariniella reported by Koubková et al. (2010) from Paradistichodus dimidiatus (Pellegrin) in Senegal and misidentified as C. gonzalesi Van Waerebeke, Chabaud, Bain et Georges, 1988 are considered to represent a new species, C. koubkovae sp. n.; this is established by reference to the description and drawings provided by Koubková et al. (2010)., František Moravec, Liesl L. Van As., and Obsahuje bibliografii
a1_Different parameters that vary during leaf development may be affected by light intensity. To study the influence of different light intensities on primary leaf senescence, sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1. Plants grown under HI exhibited greater specific leaf mass referred to dry mass, leaf area and soluble protein at the beginning of the leaf development. This might have resulted from the increased CO2 fixation rate observed in HI plants, during early development of primary leaves. Chlorophyll a and b contents in HI plants were lower than in LI plants in young leaves. By contrast, the carotenoid content was significantly higher in HI plants. Glucose concentration increased with the leaf age in both treatments (HI and LI), while the starch content decreased sharply in HI plants, but only slightly in LI plants. Glucose contents were higher in HI plants than in LI plants; the differences were statistically significant (p<0.05) mainly at the beginning of the leaf senescence. On the other hand, starch contents were higher in HI plants than in LI plants, throughout the whole leaf development period. Nitrate reductase (NR) activity decreased with leaf ageing in both treatments. However, the NR activation state was higher during early leaf development and decreased more markedly in senescent leaves in plants grown under HI. GS activity also decreased during sunflower leaf ageing under both PFD conditions, but HI plants showed higher GS activities than LI plants. Aminating and deaminating activities of glutamate dehydrogenase (GDH) peaked at 50 days (senescent leaves). GDH deaminating activity increased 5-fold during the leaf development in HI plants, but only 2-fold in LI plants., a2_ The plants grown under HI exhibited considerable oxidative stress in vivo during the leaf senescence, as revealed by the substantial H2O2 accumulation and the sharply decrease in the antioxidant enzymes, catalase and ascorbate peroxidase, in comparison with LI plants. Probably, systemic signals triggered by a high PFD caused early senescence and diminished oxidative protection in primary leaves of sunflower plants as a result., L. De la Mata ... [et al.]., and Obsahuje bibliografii
Plants experience multiple abiotic stresses during the same growing season. The implications of submergence with and without saline water on growth and survival were investigated using four contrasting rice cultivars, FR13A (submergence-tolerant, salinity-susceptible), IR42 (susceptible to salinity and submergence), and Rashpanjor and AC39416 (salinity-tolerant, submergence-susceptible). Though both FR13A and IR42 showed sensitivity to salinity, FR13A exhibited higher initial biomass as well as maintained greater dry mass under saline condition. Greater reduction of chlorophyll (Chl) contents due to salinity was observed in the susceptible cultivars, including FR13A, compared to the salinity-tolerant cultivars. Exposure of plants to salinity before submergence decreased the survival chance under submergence. Yet, survival percentage under submergence was greater in FR13A compared to other cultivars. Generally, the reduction in the Chl content and damage to PSII were higher under the submergence compared to salinity conditions. The submergence-tolerant cultivar, FR13A, maintained greater quantities of Chl during submergence compared to other cultivars. Quantification of the Chl a fluorescence transients (JIP-test) revealed large cultivar differences in the response of PSII to submergence in saline and nonsaline water. The submergence-tolerant cultivar maintained greater chloroplast structural integrity and functional ability irrespective of the quality of flooding water., R. K. Sarkar, Anuprita Ray., and Obsahuje seznam literatury
Fossil continental molluscs have not hitherto been regarded as reliable paleoenvironmental indicators. Little was known about their ecological requirements or their position in characteristic biomes of the Quaternary climatic cycle, for instance in the loess steppe. Only recent analyses of their assemblages in a broad environmental context have shown that they are indicative of a number of important environmental phenomena in the same way as pollen grains or vertebrate remains. and Vojen Ložek.
Fossil molluscan successions from ca 450 sites provide evidence of the paleo-environmental history of the Czech Republic and Slovakia during the Quaternary. They not only reflect the Quaternary cycle of warm and cold phases but also a number of various events, such as the impact of the cold oscillation at 8,2 ky BP or the detailed reconstruction in time and space of the habitat patchwork in areas where other fossils are sparse or absent, particularly in karstlands, in the full scale of elevations. and Vojen Ložek.
Clear-cutting, the main method of harvesting in many forests in the world, causes a series of dramatic environmental changes to the forest habitat and removes habitat resources for arboreal and epigeal species. It results in considerable changes in the composition of both plant and animal communities. Ants have many critical roles in the maintenance and functioning of forest ecosystems. Therefore, the response of ants to clear-cutting and the time it takes for an ant community to recover after clear-cutting are important indicators of the effect of this harvesting technique on the forest ecosystem. We investigated ground-dwelling ant communities during secondary succession of deciduous forests in Transylvania, Romania. Using space-for-time substitution, we explored a chronosequence from clear-cuts to mature forests (> 120 years). The object was to determine if cutting has measurable effects on ant community structure, and if ant species richness differs between successional stages. We recorded a total of 24 species of ants, 11 characteristic of forests and seven of open landscape. Ant species richness was higher in clear-cuts compared to closed-canopy and old stands. Number of ant individuals was highest in young age classes and lowest in closed-canopy age classes. There was no drastic change in species richness during the succession, however differences in community composition at different stages were recorded. Open landscape species are able to rapidly colonize following disturbance but disappear when the forest sites mature and many forest ant species are capable of surviving clear cutting., Ioan Tăuşan, Jens Dauber, Maria R. Trică, Bálint Markó., and Obsahuje bibliografii
Průběh počasí a v dlouhodobém pohledu podnebí patří k limitujícím podmínkám pro výskyt organismů, dokladem je výskyt teplomilných a naopak i chladnomilných nebo suchomilných a mokřadních druhů na našem území. A nejde pouze o přirozená společenstva, rozdíly nacházíme i ve skladbě pěstovaných plodin. Plošnou proměnlivost ovlivňují rozdílné klimatické podmínky - kromě podnebí hrají roli také půdní vlastnosti, které i díky odlišným geologickým podmínkám jsou velmi různorodé. Podnebí je však nejdynamičtější složkou přírodního prostředí. A právě pro území České republiky je typická vysoká proměnlivost podnebí i počasí v čase. Sucho se v posledních letech vyskytuje stále častěji, což však není dáno pouze nedostatkem srážek, ale také schopností krajiny zadržet vodu. Označení „sucho“ je výraz v obecném pojetí dosti neurčitý a v různých vědních i hospodářských oborech odlišně definovaný. Sucho meteorologické je nejčastěji vyjádřené časovými a prostorovými deficity srážek, které představují prvotní příčiny výskytu tohoto jevu. Kromě množství a intenzity spadlých srážek vztažených k dlouhodobým srážkovým úhrnům pro dané místo a roční dobu stanovili mnozí autoři různé definice sucha, a to v závislosti i na dalších klimatologických prvcích (teplota vzduchu, výpar, rychlost větru, vlhkost vzduchu aj.). Sucho zemědělské (agronomické) je vyjádřeno nedostatkem vody v půdě pro zemědělské plodiny ovlivněným předchozím nebo stále trvajícím výskytem meteorologického sucha. Z hlediska vodních poměrů v krajině je pak důležité sucho hydrologické. Člověk svou činností ovlivňuje krajinu, což platí i pro území ČR, kde může časem nastat nedostatek vody, a proto bychom se při hospodaření v krajině měli zaměřit, Climate has a substantial influence on the occurrence of organisms and thanks to its high variability various communities are to be found on our territory. The last years have seen increasingly frequent extreme climatic events, including the occurrence of serious drought. To assess the occurrence of drought the moisture balance method (difference between total precipitation and potential evapotranspiration) is the most frequently used. The extent and intensity of drought also depend on water retention capacity of the landscape. In view of possible climate change (particularly increase in air temperature), more pronounced drought periods may occcur in the near future., and Jaroslav Rožnovský.
V naší fauně jsou známy dva původní druhy suchozemských neparazitických ploštěnců (Microplana terrestris a M. humicola) a další dva nepůvodní druhy se pravidelně vyskytují ve sklenících (Bipalium kewense a Rhynchodemus sylvaticus). Výskyt druhého z nepůvodních druhů je pravděpodobný i ve volné přírodě., Two native species of free-living terrestrial flatworms (Microplana terrestris and M. humicola) are known in the wild of the Czech Republic and two other non-native species (Bipalium kewense and Rhynchodemus sylvaticus) have been repeatedly recorded in the greenhouses. The occurrence of the later non-native species is also likely in the outdoors., and Michal Horsák.
We report results of a faunal survey of Aradidae flat bugs sampled by sifting litter in 14 wet and discrete Tanzanian primary forests (= Tanzanian Forest Archipelago, TFA) of different geological origins and ages. Images, locality data and, when available, DNA barcoding sequences of 300 Aradidae adults and nymphs forming the core of the herein analyzed data are publicly available online at dx.doi.org/10.5883/DS-ARADTZ. Three Aradidae subfamilies and seven genera were recorded: Aneurinae (Paraneurus), Carventinae (Dundocoris) and Mezirinae (Afropictinus, Embuana, Linnavuoriessa, Neochelonoderus, Usumbaraia); the two latter subfamilies were also represented by specimens not assignable to nominal genera. Barring the six nominal species of Neochelonoderus and Afropictinus described earlier by us from these samples and representing 11 of the herein defined Operational Taxonomic Units (OTU), only one of the remaining 52 OTUs could be assigned to a named species; the remaining 51 OTUs (81%) represent unnamed species. Average diversity of Aradidae is 4.64 species per locality; diversity on the three geologically young volcanoes (Mts Hanang, Meru, Kilimanjaro) is significantly lower (1.33) than on the nine Eastern Arc Mountains (5.67) and in two lowland forests (5). Observed phylogeographic structure of Aradidae in TFA can be attributed to vicariance, while the depauperate fauna of Aradidae on geologically young Tanzanian volcanoes was likely formed anew by colonisation from nearby and geologically older forests., Vasily V. Grebennikov, Ernst Heiss., and Obsahuje bibliografii
1_Red wood ants are ecologically important members of woodland communities, and some species are of conservation concern. They occur commonly only in certain habitats in Britain, but there is limited knowledge of their numbers and distribution. This study provided baseline information at a key locality (Abernethy Forest, 37 km2) in the central Highlands of Scotland and trialed a new method of surveying red wood ant density and stand type associations: a distance sampling line transect survey of nests. This method is efficient because it allows an observer to quickly survey a large area either side of transect lines, without having to assume that all nests are detected. Instead, data collected on the distance of nests from the line are used to estimate probability of detection and the effective transect width, using the free software "Distance". Surveys took place in August and September 2003 along a total of 71.2 km of parallel, equally-spaced transects. One hundred and forty-four red wood ant nests were located, comprising 89 F. aquilonia (Yarrow, 1955) and 55 F. lugubris (Zetterstedt, 1838) nests. Estimated densities were 1.13 nests per hectare (95% CI 0.74–1.73) for F. aquilonia and 0.83 nests per hectare (95% CI 0.32–2.17) for F. lugubris. These translated to total estimated nest numbers of 4,200 (95% CI 2,700–6,400) and 3,100 (95% CI 1,200–8,100), respectively, for the whole forest. Indices of stand selection indicated that F. aquilonia had some positive association with old-growth and F. lugubris with younger stands (stem exclusion stage). No nests were found in areas that had been clear-felled, and ploughed and planted in the 1970s–1990s. The pattern of stand type association and hence distribution of F. aquilonia and F. lugubris may be due to the differing ability to disperse (F. lugubris is the faster disperser) and compete (F. aquilonia is competitively superior)., 2_We recommend using line transect sampling for extensive surveys of ants that construct nest mounds to estimate abundance and stand type association., Kerry M. Borkin, Ron W. Summers, Len Thomas., and Obsahuje seznam literatury