Wind dispersal in freshwater wetlands: Knowledge for conservation and restoration

Questions: For wetland plants, dispersal by wind is often overlooked because dispersal by water is generally assumed to be the key dispersal process. This literature review addresses the role of seed dispersal by wind in wetlands. Why is wind dispersal relevant in wetlands? Which seeds are dispersed by wind and how far? And how can our understanding of wind dispersal be applied to wetland conservation and restoration? Methods: Literature review. Results and conclusions: Wind is a widely available seed dispersal vector in wetlands and can transport many seeds over long distances. Unlike water, wind can transport seeds in all directions and is therefore important for dispersal to upstream wetlands and to wetlands not connected by surface water flows. Wind dispersal transports seeds to a wider range of sites than water, and therefore reaches more sites but with lower seed densities. Many wetland plant species have adaptations to facilitate wind dispersal. Dispersal distances increase with decreasing falling velocity of seeds, increasing seed release height and selective release mechanisms. Depending on the adaptations, seeds may be dispersed by wind over many km or only a few m. The frequency of long‐distance wind dispersal events depends on these adaptations, the number of produced seeds, the structure of the surrounding vegetation, and the frequency of occurrence of suitable weather conditions. Humans reduce the frequency of successful long‐distance wind dispersal events in wetlands through wetland loss and fragmentation (which reduce the number and quality of seeds) and eutrophication (which changes the structure of the vegetation so that seed release into the wind flow becomes more difficult). This is yet another reason to focus on wetland conservation and restoration measures at increased population sizes, prevention of eutrophication, and the restoration of sites at short distances from seed sources.     

Pasteurella] caballi infection not limited to horses - a closer look at taxon 42 of Bisgaard

AIM: To investigate if taxon 42 of Bisgaard isolated from pigs represents genuine [Pasteurella] caballi, which was previously only isolated from horses. METHODS AND RESULTS: A total of 15 field isolates from horses and pigs from five different countries representing three continents were subjected to extended phenotypical characterization. Although minor differences were observed between taxon 42 and [P.] caballi, these differences did not allow phenotypic separation. Ribotyping based on HindIII digestion showed five profiles based on nine band positions. One [P.] caballi strain and two taxon 42 strains shared the same profile. Ribotyping using HpaII gave a higher diversity with nine profiles based on ten band positions. While no profiles were shared between the taxon 42 and [P.] caballi strains, pattern analysis showed that two of the taxon 42 isolates were most similar (91% similarity) with a [P.] caballi isolate. The 16S rRNA gene sequencing of one strain of taxon 42 and one strain of [P.] caballi was performed and compared with the published sequence for the type strain of [P.] caballi. The three strains showed nearly identical sequences with at least 99.8% similarity. DNA re-associations measured by the micro-well method were 79 and 77%, respectively between the type strain of [P.] caballi and two strains of taxon 42 representing distinct ribotypes and confirmed that taxon 42 belongs to [P.] caballi. CONCLUSION: The present investigation documents that [P.] caballi can be isolated from clinical respiratory specimens from pigs and the recognized association with respiratory infections in horses and horse bite infection in humans. Strains classified as taxon 42 are [P.] caballi isolated from pigs and for both pigs and horses, lesions mainly include the respiratory tract. SIGNIFICANCE AND IMPACT OF THE STUDY: The results will improve the diagnostics and progress studies of virulence and epidemiology of [P.] caballi.     

Environmental control of clonal growth in Carex nigra: What can be masked under the name Carex nigra subsp. juncella in the Czech Republic?

Carex nigra plants forming elevated dense tussocks are often named C. nigra subsp. juncella, as opposed to rhizomatous C. nigra subsp. nigra. It is uncertain, however, whether the cespitose growth form is a hereditary trait useful for definition of the distinct taxon or a site modification of little taxonomic value. We used vegetation analyses (phytosociological relevés) to reveal main patterns in ecological demands of the cespitose C. nigra plants in the Czech Republic, and three cultivation experiments to assess changes in clonal growth of C. nigra under various environmental conditions. In the field the cespitose C. nigra plants were typically found in abandoned wet meadows near open water, whereas the rhizomatous morphotypes frequently occurred also in regularly mown wet meadows and in peat bogs. The cespitose growth form disappeared in the cultivations, and the rhizome system responded plastically to immediate environmental stimuli. Number of rhizome branches and mean rhizome length decreased after defoliation of aboveground parts and denudation of belowground parts, whereas increased due to inundation. In the population from a cold site in high altitude (Modrava, Šumava Mts.), however, the originally cespitose plants repeatedly produced shorter and less numerous rhizome branches than the rhizomatous plants cultivated in the same conditions. This suggests ecotypic (genetic) differentiation in some populations of C. nigra, driven by environmental selection for more compact growth form in climatically severe sites. The cespitose C. nigra plants thus arise polytopically, by different mechanisms. The growth form itself therefore cannot serve as the character reliably delimiting C. nigra subsp. juncella as the distinct taxon.     

Roller Chopping Effectively Reduces Shrub Cover and Density in Pine Flatwoods

Changes to fire regimes have resulted in excessive shrub growth and declines in the species rich herbaceous ground layer of pyric savanna and grassland systems worldwide, including the pine flatwoods of the Southern Coastal Plain of the United States. Prescribed burning and roller chopping during growing (April–October) and dormant (November–March) seasons are management practices promoted to reduce shrub invasion and increase herbaceous plant growth in flatwoods. However, relatively little is known about the seasonal effects these activities have on shrubs and herbaceous vegetation. We assessed the effects of prescribed burning and roller chopping on herbaceous and shrub characteristics in pine flatwoods and explored how grazing may mediate these treatments. We used a paired design, with comparison made between sampling locations randomly located within treated (e.g. burned) and adjacent untreated areas. Growing season burning was more effective at reducing shrub cover and height than dormant season burning. However, shrub re‐growth occurred the second year post‐burn. Roller chopping and roller chopping/burning combinations led to decreases in shrub cover and height for 2 years post‐treatment. Decreases in shrub density were seen on sites subject to growing season roller chopping and grazing. Decreases in herbaceous vegetation were observed following all treatments, possibly the result of grazing. If reductions in shrub density are required, growing season roller chopping in combination with grazing may be the only effective treatment. However, initial deferment from grazing following burning and roller chopping treatments may be necessary to permit re‐establishment and growth of forbs and graminoids.     

Two new freshwater fish species of the genus Telestes (Actinopterygii, Cyprinidae) from karst poljes in Eastern Herzegovina and Dubrovnik littoral (Bosnia and Herzegovina and Croatia)

Two new species, Telestes dabar and Telestes miloradi, are described on the basis of morphological comparisons of isolated geographical populations of fishes identified earlier as Telestes metohiensis. A lectotype is designated for Telestes metohiensis, whose range is shown to include waters of Gatačko, Cerničko, and Nevesinjsko poljes in Eastern Herzegovina. Telestes dabar from Dabarsko Polje (Eastern Herzegovina) and Telestes miloradi from Konavosko Polje (south Croatia) share with Telestes metohiensis the following combination of characters that distinguish them from the rest of the genus Telestes: pharyngeal teeth in one row, usually 5–4; preoperculo-mandibular canal not communicating with the infraorbital canal; mouth subterminal, the tip of the mouth cleft on or below the level of the ventral margin of the eye; postcleithrum minute or absent; ventral portion of the trunk with a dark stripe on a pale background; and dorsal portion of trunk uniformly dark and bordered ventrally by a dark midlateral stripe. Telestes dabar and Telestes miloradi are distinguishable from Telestes metohiensis in usually having 8½ branched dorsal-fin rays (vs. usually 7½), 9 or 10 gill rakers (vs. 7–10, usually 8), and the dark stripe on the ventral portion of the trunk below the main pigmented area of the back narrow and usually not reaching posteriorly to the caudal peduncle (vs. dark stripe wide and extending posteriorly to the caudal peduncle). Telestes dabar is distinguished from Telestes miloradi by having scales on most of the body situated close to one another and overlapping in a region behind the pectoral girdle and usually on the caudal peduncle (vs. overlapping scales on most of the body); the lateral line usually incomplete and interrupted, with 24–69, usually 54–65, total scales (vs. lateral line usually complete, with 55–67 total scales); scales above and below the lateral line slightly smaller than lateral-line scales (vs. of about equal size); head width 43–52% HL (vs. 48–58% HL); and lower jaw length 10–12% SL or 36–41% HL (vs. 8–10% SL or 33–38% HL). Telestes miloradi, a very local endemic species,is known only by historical samples. Telestes dabar is an abundant fish in Dabarsko Polje, but its range is critically restricted during the dry season by a few permanent sources. Nothing is known about its occurrence in underground karst waters.     

Pollen productivity estimates of key European plant taxa for quantitative reconstruction of past vegetation: a review

Information on the spatial distribution of past vegetation on local, regional and global scales is increasingly used within climate modelling, nature conservancy and archaeology. It is possible to obtain such information from fossil pollen records in lakes and bogs using the landscape reconstruction algorithm (LRA) and its two models, REVEALS and LOVE. These models assume that reliable pollen productivity estimates (PPEs) are available for the plant taxa involved in the quantitative reconstructions of past vegetation, and that PPEs are constant through time. This paper presents and discusses the PPEs for 15 tree and 18 herb taxa obtained in nine study areas of Europe. Observed differences in PPEs between regions may be explained by methodological issues and environmental variables, of which climate and related factors such as reproduction strategies and growth forms appear to be the most important. An evaluation of the PPEs at hand so far suggests that they can be used in modelling applications and quantitative reconstructions of past vegetation, provided that consideration of past environmental variability within the region is used to inform selection of PPEs, and bearing in mind that PPEs might have changed through time as a response to climate change. Application of a range of possible PPEs will allow a better evaluation of the results.     

竹亚科刚竹属植物的修订(Ⅲ)

作为对刚竹属 (Phyllostachys Sieb.et Zucc.)一些类群加以评注的第三部分 ,讨论了金竹 (Ph.sul-phurea(Carr.) A.et C.Riv.)在中国的分布 ,明确了它的具体产地 ,确认了它在华东皖浙赣毗邻地区仍然存在着一定数量的野生居群 ;同时还对本种种下变异类型重新作了分类学处理 ,承认其下包括 1变种 3变型 ,作出 1个新组合 ,归并了 2个不可靠的变型的拉丁学名和 5个命名上多余的拉丁学名。     

陷胸式蜂亚科（昆虫纲）化石在我国辽西上侏罗统的发现及其系统演化

描述产自辽宁北票上园地区黄半吉沟上侏罗统义县组下部膜翅目昆虫化石1新属新种Trematothoracoides liaoningensis gen.et sp.nov.,归入薤式产（Sepulcidae)中的陷胸茎蜂亚科（Trematothoracinae)。这是首次在我国发现可行的陷胸茎蜂化石,也是该亚科在侏罗纪的产次报道,分支分析结果表明Trematothoracinae为一单系类群。Thoracotrema与Prosyntexis进化程度较高,构成一对姊妹群,同时又是Trematothorax的姊妹群,Trematothoracoides最为原始,为Thoracotrema Prosymtexis Trematothorax的姊妹群。     

Abundance and habitat segregation in Mediterranean grassland species: the importance of seed weight

Abstract. We analysed the relationship between seed traits (weight, shape and dispersal structures) and the abundance and habitat segregation of Mediterranean grassland species. To take into account possible correlations with other plant traits, the study also includes 5 vegetative traits (growth form, plant longevity, clonality, onset of flowering and plant size) of commonly accepted functional importance. Data were recorded for 85 species from dehesa grasslands in central Spain. Species abundance was measured in upper (dry and less productive, high stress) and lower (moist and more productive, low stress) slope zones in the same area. Habitat segregation was estimated using an index based on the relative frequencies of species in upper and lower slope zones. Multiple regression models were fitted using species, as well as phylogenetically independent contrasts, as data points. Annual small‐seeded species without specialised dispersal structures are over‐represented in dehesa grasslands. Abundance was negatively related to seed weight in upper slope zones. None of the recorded plant traits were related to abundance in the lower slope zones. Habitat segregation was mainly related to seed weight, but also to some vegetative traits. Annual, early flowering and small‐seeded species were relatively more abundant in the upper than the lower slope zones. This pattern is independent of phylogeny. Our results suggest that in dry Mediterranean grasslands, abundance of many species is determined by dispersal (production of numerous small seeds) rather than by competitive ability.