Research on canopy arthropods has progressed from species inventories to the study of their interactions and networks, enhancing our understanding of how hyper-diverse communities are maintained. Previous studies often focused on sampling individual tree species, individual trees or their parts. We argue that such selective sampling is not ideal when analyzing interaction network structure, and may lead to erroneous conclusions. We developed practical and reproducible sampling guidelines for the plot-based analysis of arthropod interaction networks in forest canopies. Our sampling protocol focused on insect herbivores (leaf-chewing insect larvae, miners and gallers) and non-flying invertebrate predators (spiders and ants). We quantitatively sampled the focal arthropods from felled trees, or from trees accessed by canopy cranes or cherry pickers in 53 0.1 ha forest plots in five biogeographic regions, comprising 6,280 trees in total. All three methods required a similar sampling effort and provided good foliage accessibility. Furthermore, we compared interaction networks derived from plot-based data to interaction networks derived from simulated non-plot-based data focusing either on common tree species or a representative selection of tree families. All types of non-plot-based data showed highly biased network structure towards higher connectance, higher web asymmetry, and higher nestedness temperature when compared with plot-based data. Furthermore, some types of non-plot-based data showed biased diversity of the associated herbivore species and specificity of their interactions. Plot-based sampling thus appears to be the most rigorous approach for reconstructing realistic, quantitative plant-arthropod interaction networks that are comparable across sites and regions. Studies of plant interactions have greatly benefited from a plot-based approach and we argue that studies of arthropod interactions would benefit in the same way. We conclude that plot-based studies on canopy arthropods would yield important insights into the processes of interaction network assembly and dynamics, which could be maximised via a coordinated network of plot-based study sites.

• MeSH
• členovci fyziologie   MeSH
• interakce hostitele a parazita * MeSH
• larva fyziologie   MeSH
• lesy MeSH
• rostliny parazitologie   MeSH
• stromy parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Following a pine beetle epidemic in British Columbia, Canada, we investigated the effect of fire severity on rhizosphere soil chemistry and ectomycorrhizal fungi (ECM) and associated denitrifying and nitrogen (N)-fixing bacteria in the root systems of regenerating lodgepole pine seedlings at two site types (wet and dry) and three fire severities (low, moderate, and high). The site type was found to have a much larger impact on all measurements than fire severity. Wet and dry sites differed significantly for almost all soil properties measured, with higher values identified from wet types, except for pH and percent sand that were greater on dry sites. Fire severity caused few changes in soil chemical status. Generally, bacterial communities differed little, whereas ECM morphotype analysis revealed ectomycorrhizal diversity was lower on dry sites, with a corresponding division in community structure between wet and dry sites. Molecular profiling of the fungal ITS region confirmed these results, with a clear difference in community structure seen between wet and dry sites. The ability of ECM fungi to colonize seedlings growing in both wet and dry soils may positively contribute to subsequent regeneration. We conclude that despite consecutive landscape disturbances (mountain pine beetle infestation followed by wildfire), the "signature" of moisture on chemistry and ECM community structure remained pronounced.

• MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   metabolismus   MeSH
• borovice růst a vývoj   mikrobiologie   parazitologie   MeSH
• brouci fyziologie   MeSH
• dusík metabolismus   MeSH
• ekosystém MeSH
• houby klasifikace   genetika   izolace a purifikace   MeSH
• mykorhiza klasifikace   genetika   růst a vývoj   izolace a purifikace   MeSH
• nemoci rostlin parazitologie   MeSH
• požáry MeSH
• půda chemie   MeSH
• rhizosféra MeSH
• stromy růst a vývoj   mikrobiologie   parazitologie   MeSH
• voda analýza   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Phytophthora plurivora and other Phytophthora species are known to be serious pathogens of forest trees. Little is known, however, about the presence of P. plurivora in Polish oak forests and their role in oak decline. The aims of this study were to identify P. plurivora in healthy and declining Quercus robur stands in southern Poland and to demonstrate the relationship between different site factors and the occurrence of P. plurivora. In addition, the virulence of P. plurivora and other Phytophthora species was evaluated through inoculations using 2-year-old oak seedlings. Rhizosphere soil was investigated from 39 oak stands representing different healthy tree statuses. The morphology and DNA sequences of the internal transcribed spacer regions (ITS) of the ribosomal DNA and the mitochondrial cox1 gene were used for identifications. P. plurivora, an oak fine root pathogen, was isolated from rhizosphere soil samples in 6 out of 39 stands. Additionally, Phytophthora cambivora, Phytophthora polonica and Phytophthora rosacearum-like were also obtained from several stands. The results showed a significant association between the presence of P. plurivora and the health status of oak trees. Similar relationships were also observed for all identified Phytophthora species. In addition, there was evidence for a connection between the presence of all identified Phytophthora species and some site conditions. Phytophthora spp. occurred more frequently in declining stands and in silt loam and sandy loam soils with pH ≥ 3.66. P. plurivora and P. cambivora were the only species capable of killing whole plants, producing extensive necrosis on seedling stems.

• MeSH
• dub (rod) parazitologie   MeSH
• fylogeneze MeSH
• kořeny rostlin parazitologie   MeSH
• lesy MeSH
• molekulární sekvence - údaje MeSH
• nemoci rostlin parazitologie   MeSH
• Phytophthora klasifikace   genetika   izolace a purifikace   MeSH
• stromy parazitologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Polsko MeSH

Classical niche theory explains the coexistence of species through their exploitation of different resources. Assemblages of herbivores coexisting on a particular plant species are thus expected to be dominated by species from host-specific guilds with narrow, coexistence-facilitating niches rather than by species from generalist guilds. Exactly the opposite pattern is observed for folivores feeding on trees in New Guinea. The least specialized mobile chewers were the most species rich, followed by the moderately specialized semiconcealed and exposed chewers. The highly specialized miners and mesophyll suckers were the least species-rich guilds. The Poisson distribution of herbivore species richness among plant species in specialized guilds and the absence of a negative correlation between species richness in different guilds on the same plant species suggest that these guilds are not saturated with species. We show that herbivore assemblages are enriched with generalists because these are more completely sampled from regional species pools. Herbivore diversity increases as a power function of plant diversity, and the rate of increase is inversely related to host specificity. The relative species diversity among guilds is thus scale dependent, as the importance of specialized guilds increases with plant diversity. Specialized insect guilds may therefore comprise a larger component of overall diversity in the tropics (where they are also poorly known taxonomically) than in the temperate zone, which has lower plant diversity.

• MeSH
• biodiverzita MeSH
• biologická adaptace fyziologie   MeSH
• biologické modely MeSH
• druhová specificita MeSH
• hmyz fyziologie   MeSH
• interakce hostitele a parazita MeSH
• potravní řetězec MeSH
• stromy parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Geografické názvy
• Nová Guinea MeSH

Článek popisuje metody zobrazení malého hmyzu a rostlin pomocí rentgenového záření. Měřící mikroradiografická aparatura vyvinutá na našem ústavu umožňuje zobrazování a pozorování dějů s vysokým prostorovým rozlišením. Jako zobrazovač používáme pixelový detektor Medipix2, který počítá jednotlivé částice ionizujícího záření. Jako zdroje rentgenového záření používáme rentgenky s mikroohniskem Hamamatsu a FeinFocus. Použití detektorů Medipix2 přináší nové možnosti neinvazivního zobrazení v mikroradiografii živých objektů.

We present our table experimental setup devoted to a digital high resolution X-ray in-vivo micro-radiography that was applied to imaging of small insects and plants. This setup was designed for X-ray imaging as well as for the observation of real-time in–vivo processes in living organisms. The single photon counting pixel device Medipix2 was used as an image area. Hamamatsu micro-focus X-ray tube or FeinFocus micro-focus X-ray tube were used as X-ray sources. Using of detectors Medipix2 opens new possibilities to perform non-invasive observation of living objects.

• MeSH
• Aesculus parazitologie   MeSH
• financování organizované MeSH
• fotony diagnostické užití   MeSH
• hmyz fyziologie   růst a vývoj   MeSH
• Hymenoptera fyziologie   parazitologie   růst a vývoj   MeSH
• mikroradiografie metody   přístrojové vybavení   využití   MeSH
• počítačová rentgenová tomografie metody   přístrojové vybavení   využití   MeSH
• radiometrie metody   přístrojové vybavení   využití   MeSH
• rentgendiagnostika metody   přístrojové vybavení   využití   MeSH
• rentgenové záření MeSH
• rostliny parazitologie   MeSH
• stromy parazitologie   růst a vývoj   MeSH
• vývoj rostlin MeSH

• MeSH
• ekosystém MeSH
• finanční podpora výzkumu jako téma MeSH
• hustota populace MeSH
• Lepidoptera fyziologie   klasifikace   MeSH
• stromy parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Geografické názvy
• Papua Nová Guinea MeSH

• MeSH
• biologická kontrola škůdců MeSH
• entomologie MeSH
• lesnictví MeSH
• stromy parazitologie   MeSH
• Geografické názvy
• Česká republika MeSH

• MeSH
• hlístice MeSH
• nemoci rostlin statistika a číselné údaje   MeSH
• rostlinné viry MeSH
• stromy mikrobiologie   parazitologie   MeSH
• Publikační typ
• srovnávací studie MeSH
• Geografické názvy
• Slovenská republika MeSH