Gram-negative, motile, rod-shaped bacterial strains (designated 4F2
and Kf) were isolated from decaying tissues of various deciduous tree species. Phylogenetic analyses based on their 16S rRNA gene ...sequences showed that the novel isolates belong to the genus
and showed highest (98.3 %) sequence similarity to
. Isolate 4F2
formed a separate branch on the phylogenetic tree based on concatenated sequences of four housekeeping genes or whole genome sequences, clearly separate from
, suggesting that novel isolates should belong to a novel species. Orthologous average nucleotide identity scores and
DNA-DNA hybridization values between isolate 4F2
and type strains of other species in the genus
were less than 85 and 30 %, respectively, significantly lower than the species boundary cut-off values (95 and 70 %). A negative reaction for β-galactosidase, the ability to use dextrin and maltose as carbon sources, and an inability to use lactose are the main phenotypic characteristics that can be used to differentiate the novel isolates from
. Based on phenotypic and genotypic characteristics, isolates 4F2
and Kf belong to a novel species of the genus
, for which the name
sp. nov. is proposed. The type strain is 4F2
(=NCAIM B 02661
=LMG 32183
).
Urbanization is one of the most severe forms of environmental alteration, in which increasing human settlement leads to an unprecedented loss of natural areas, thereby threatening global biodiversity ...and associated ecosystem functions. Consequently, the evidence base needs to be strengthened in order to understand how this man-made alteration affects urban biodiversity, and hence develop appropriate conservation measures. According to our expectations, urbanization processes influence the abundance of passerine birds through functional traits, what we studied within the framework of a systematic review using phylogenetically controlled meta-analyses. We tested four specific predictions: (i) Migration strategy will influence responses to urbanization, and tropical migrants will be the least numerous in urban areas; (ii) Birds nesting at ground level will be negatively affected by urbanization, while birds nesting at higher levels will suffer less; (iii) In terms of foraging technique, ground probers will be negatively; and (iv) birds with insectivorous diet will be the most disadvantaged in cities. Bird species (N = 53) were studied along urbanization gradients that ranged from highly urbanized areas to adjacent natural areas. Our findings revealed that the impact of urbanization on the abundance of bird species is modulated by certain functional traits. Partial or short distance migrants, ground nesters, ground gleaners and granivores were the group of species most negatively influenced by urbanization. Species sensitive to urbanization were those that are linked in some way to open grassland areas. This indicates that cities need more intact and extensively managed grasslands to sustain bird communities, which provide valuable ecosystem services.
Habitat fragmentation is considered one of the most severe threatening factors for global biodiversity. Here we assessed, how local and landscape scale environmental variables, such as fragment size ...(small vs. large) and landscape configuration (measured as connectivity index) relates to bird community composition, species richness, abundance and functional diversity. We surveyed 60 grassland fragments in Hungary, belonging to two different threatened grassland types, namely forest-steppes and kurgans. Forest-steppes are natural mosaics of grasslands and forests at the contact zone between closed-canopy temperate forests and steppe grasslands. Kurgans are ancient burial mounds, found on the Eurasian steppe and forest steppe zone. These fragments were embedded in plantation forestry, respectively, agricultural matrix with gradients of size and connectivity. Both habitats are threatened by forestry and agricultural intensification, though these fragments may serve as important wildlife refuges. Our findings revealed that forest-steppe birds were more diverse and abundant in large and well-connected than in small isolated fragments. High connectivity affected ground nesting birds in small forest-steppe fragments positively. Birds inhabiting kurgan area showed higher trait similarity in well-connected than in isolated fragments. Bird abundance of kurgans associated with small home range size and ground feeding habit were higher in connected compared to isolated fragments. Highly isolated kurgans filtered for more specialised bird species but not for generalists. We provide conservation implications for enhancing grassland specialist bird communities, which consist of preservation of large, well-connected grassland fragments within production landscapes and through reconsideration of the currently used intensive forestry.
•Forest-steppe birds were more diverse and abundant in large and connected fragments.•Connectivity increased ground nesting birds in small forest-steppe fragments.•Kurgan birds showed higher trait similarity in better connected fragments.•Connectivity increased kurgan birds of small home range and ground feeding habit.•Highly isolated kurgans filtered for more specialised bird species.
As a consequence of agricultural intensification and habitat fragmentation since the mid-20th century, biological diversity has declined considerably throughout the world, particularly in Europe. We ...assessed how habitat and landscape-scale heterogeneity, such as variation in fragment size (small vs. large) and landscape configuration (measured as connectivity index), affect plant and arthropod diversity. We focused on arthropods with different feeding behaviour and mobility, spiders (predators, moderate dispersal), true bugs (mainly herbivores and omnivores with moderate dispersal), wild bees (pollinators with good dispersal abilities), and wasps (pollinators, omnivores with good dispersal abilities). We studied 60 dry grassland fragments in the same region (Hungarian Great Plain); 30 fragments were represented by the grassland component of forest-steppe stands, and 30 were situated on burial mounds (kurgans). Forest-steppes are mosaics of dry grasslands with small forests in a matrix of plantation forests. Kurgans are ancient burial mounds with moderately disturbed grasslands surrounded by agricultural fields. The size of fragments ranged between 0.16–6.88 ha (small: 0.16–0.48 ha, large: 0.93–6.88 ha) for forest-steppes and 0.01–0.44 ha (small: 0.01–0.10 ha and large: 0.20–0.44 ha) for kurgans. Fragments also represented an isolation gradient from almost cleared and homogenous landscapes, to landscapes with relatively high compositional heterogeneity. Fragment size, connectivity, and their interaction affected specialist and generalist species abundances of forest-steppes and kurgans. Large fragments had higher species richness of ground-dwelling spiders, and the effect of connectivity was more strongly positive for specialist arthropods and more strongly negative for generalists in large than in small fragments. However, we also found a strong positive impact of connectivity for generalist plants in small kurgans in contrast to larger ones. We conclude that besides the well-known effect of enhancing habitat quality, increasing connectivity between fragments by restoring natural and semi-natural habitat patches would help to maintain grassland biodiversity.
Seven Gram-negative bacterial strains were isolated from oozing bark canker of poplar (Populus×euramericana) trees in Hungary. They showed high (>98.3 %) 16S rRNA gene sequence similarity to ...Lonsdalea quercina; however, they differed from this species in several phenotypic characteristics. Multilocus sequence analysis based on three housekeeping genes (gyrB, atpD and infB) revealed, and DNA–DNA hybridization analysis confirmed, that this group of bacterial strains forms a distinct lineage within the species Lonsdalea quercina. A detailed study of phenotypic and physiological characteristics confirmed the separation of isolates from poplars from other subspecies of L. quercina; therefore, a novel subspecies, Lonsdalea quercina subsp. populi, type strain NY060T ( = DSM 25466T = NCAIM B 02483T), is proposed.
Habitat fragmentation threatens terrestrial arthropod biodiversity, and thereby also leads to alterations of ecosystem functioning and stability. Predation on insects and seeds by arthropods are two ...very important ecological functions because of their community-structuring effects. We addressed the effect of fragment connectivity, fragment size, and edge effect on insect and seed predation of arthropods. We studied 60 natural fragments of two grassland ecosystems in the same region (Hungarian Great Plain), 30 forest-steppes, and 30 burial mounds (kurgans). The size of fragments were in the range of 0.16–6.88 ha for forest-steppe and 0.01–0.44 ha for kurgan. We used 2400 sentinel arthropod preys (dummy caterpillars) and 4800 seeds in trays for the measurements. Attack marks on dummy caterpillars were used for predator identification and calculation of insect predation rates. In the case of seeds, predation rates were calculated as the number of missing or damaged seeds per total number of exposed seeds. Increasing connectivity played a role only in generally small kurgans, with a negative effect on insect and seed predation rates in the edges. In contrast, fragment size moderated edge effects on insect and seed predation rates in generally large forest-steppes. The difference between edges and centres was more pronounced in small than in large fragments. Our study emphasizes the important role of landscape and fragment-scale factors interacting with edge effect in shaping ecosystem functions in natural grassland fragments of modified landscapes. Managing functional landscapes to optimize the assessment of ecosystem functions and services needs a multispatial scale approach.
Populus × euramericana (Dode) Guinier clone (cl.) “I-214” is a fast-growing interspecific hybrid between Eastern cottonwood (P. deltoides Bartr. ex Marsh) and European black poplar (Populus nigra ...L.). Populus × euramericana was introduced into Serbia in the 1950s and has become one of the most widely grown poplar species. In September 2019, cankers were observed on stems and branches of P. × euramericana cl. “I-214” trees in a two-year-old poplar plantation in the province of Vojvodina, Serbia. The canker tissue was soft and watery, and a colorless fluid that smelled rotten flowed from the cracks in the bark, suggesting possible bacterial disease. After two weeks, diseased trees experienced crown die-back and oozing of foamy, odorous exudates and this study aimed to identify the causal agent of the disease. Canker margins and exudates were collected from 20 symptomatic trees. The associated bacterium was isolated and identified using biochemical characteristics, phylogenetic analyses based on 16S rRNA gene sequences, and multilocus sequence analyses (MLSA) based on partial sequencing of three housekeeping genes (gyrB, infB, and atpD). The pathogen was identified as Lonsdalea populi. Pathogenicity tests were conducted on rooted cuttings of P. × euramericana cl. “I-214” in an environmental test chamber and demonstrated that the isolated bacterial strain was able to reproduce symptoms of softened, water-soaked cankers and exudation. To the best of our knowledge, this is the first report of L. populi causing bacterial canker disease on P. × euramericana cl. “I-214” in Serbia and in southeastern Europe (SEE). It is also the first report of a bacterial disease on hybrid poplars, including P. × euramericana in this country and in SEE. If the disease spreads into new areas, selection for L. populi resistance may need to be integrated into future poplar breeding programs.
Entomopathogenic nematode–bacterium complex research is being conducted in many parts of the world, and initially, a global assessment of this research was the goal of this paper. However, this was ...deemed impossible because there are so many researchers in many countries and regions working on these important biological control agents of soil pests. Accordingly, research activities from selected countries or regions are presented. In North America and Europe, emphasis was placed on the status of commercially available nematodes, whereas with other countries and regions, the emphasis was placed on the research activities with the nematode–bacterium complexes. The one exception was with Japan where the development of commercial nematodes was emphasized. In China, Korea, and India, research activities in the use of the nematode for controlling insect pests or soil plant pathogens was stressed. In Turkey where the research is in its initial stages, we report on the Turkish nematodes and their associated bacteria. In Central America, initial attempts to control insect pests and mass production research are reported, whereas in South America, the emphasis is on biological control of some insect pests and on some basic research with some of their native nematodes. The research is still in its early stages or non-existent in most African countries, but considerable research progress has been made in Egypt with these nematodes. Overall, the intensity of research varies by country or regions. In most cases, the research in developing countries shows that the emphasis is to demonstrate the usefulness of the entomopathogenic nematodes or their symbiotic bacteria against various pests. The ultimate goal of these research activities is to use them as biological control agents of soil pests.
Highlights ► The novel enzyme hexosaminidase D was detected in RA and OA synovial fibroblasts. ► TGF beta downregulated the expression of the HEXDC gene in synovial fibroblasts. ► Hexosaminidases ...were associated with extracellular vesicles of synovial fibroblasts.
PDF
