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Compact blankets of free-floating plants generate stressful aquatic environments. The response of submerged macrophytes remains largely elusive. Will they rush toward the light or rather speed up reproductive efforts and escape using propagules—the macrophyte equivalent of lifeboats? We studied the effects of complete duckweed (Lemna minor) cover on growth and reproductive fitness of macroalga Chara globularis in a pond mesocosm experiment. C. globularis growing in Lemna-covered plots lost biomass and developed longer internodes, indicating an elongative reflex to escape stress. Densities of reproductive organs per biomass unit evolved positively in open plots and negatively in covered plots, suggesting a trade-off between reproductive effort and vegetative elongation. Reproductive potential correlated significantly with incident radiation. Lemna cover, however, did not affect oospore rain—at least within the limited time span of propagule trapping. C. globularis thus displayed an ability to modify phenology in response to floating plant stress, allocating resources to internodes instead of gametangia. Nevertheless, duckweed dominance clearly suppressed the overall reproductive performance of C. globularis. The regenerative capacity of many submerged macrophytes will likely suffer from increased floating plant dominance due to global warming—unless efforts are made to reduce nutrient levels in vulnerable waterbodies. [ABSTRACT FROM AUTHOR]

The new species Hypnea corona Huisman & Petrocelli is described to accommodate specimens from Australia, New Zealand, Italy, and Japan that were previously included in the Hypnea cornuta complex but were shown by recent molecular studies to represent a species-level clade. Hypnea corona produces distinctive stellate, starch-filled propagules that are easily dislodged and serve as vegetative reproductive structures. However, similar structures are found in closely related species and thus H. corona is distinguished primarily by unique rbcL barcode sequences. [ABSTRACT FROM AUTHOR]

The detection and control of invasive alien species in marine ecosystems is especially challenging because it is difficult to visualize the full extension of an invasion, while control options are often limited. The invasive scleractinian coral Tubastraea coccinea have spread over 8000 km of the Atlantic coastline, from Florida in the USA to southern Brazil, mainly in association with oil and gas platforms. This invasive coral threatens endemic species, reduces native coral recruitment, and modifies communities and trophic interactions, posing a relevant threat to shallow Atlantic reefs. The main aim of our study was to assess the effectiveness of an ongoing T. coccinea control program by analyzing the results of control interventions on population structure and cover of the target species in its southern Atlantic limit of distribution. We also describe the reproductive effort of T. coccinea in a 12-month time span. Between 2012 and 2019, almost 14,000 colonies were removed, most of them of small size (< 5 polyps). The highest reproductive effort was observed in September. Changes in T. coccinea cover, population structure and potential local propagule supply were observed. Control activities led to a reduction in up to half the cover of the invaded area, maintained the majority of the population in non-reproductive sizes, and consequently lowered the potential local propagule supply. Our paper highlights the fundamental role of control in preventing the local spread of T. coccinea. Recommendations on management frequency and timing are also discussed in order to contribute to the improvement of management efficiency. [ABSTRACT FROM AUTHOR]

Calcifying organisms such as benthic foraminifera are susceptible to changes in ocean pH and alkalinity. Responses to these changes include variations in mortality, calcification rates or assemblage composition, which have been observed in field and experimental studies. Here we applied a growth experiment with benthic foraminiferal propagules under different pH conditions to gather insights into the effect of pH on the composition of grown assemblages. A homogeneous propagule assemblage from a local mudflat in Corfu Island (Greece) was exposed to a range of pH conditions (6.5, 7.2, 7.8 and 8.5) for 5 weeks. In a second experiment, the assemblages were first exposed to low and subsequently to high conditions for a total of 8 weeks. After termination of the experiments, we recorded high survivability and growth throughout the treatments. Analysis of the assemblage composition of the first experiments revealed a shift from porcelaneous dominated taxa in the higher pH treatments to an assemblage with higher numbers of agglutinated taxa in the lower pH treatments. Soft-shelled monothalamous species were common throughout. The second experiment revealed assemblages that were significantly dominated by porcelaneous taxa with monothalamous taxa being almost absent. The results of this study are congruent with other observations on changing assemblage compositions with changing pH from both laboratory and field studies. The fast response of the assemblages through activation of potentially dormant propagules adds insights into the mechanisms behind seasonal composition changes in naturally variable environments such as river estuaries. They also shed new light on possible effects of continuous decreases in ocean pH on shallow-water foraminiferal assemblages in future. [ABSTRACT FROM AUTHOR]

This work aims to review the existing theoretical literature and experiments on plant species colonising gaps after soil disturbance. It attempts to evaluate the various mechanisms by which plants regenerate among the soil openings within the Mediterranean temporary ponds. Intensity and frequency of disturbances are key factors in the response of communities. Knowing the specificity of plant strategies and the species assembly process is important for a better understanding of the impact of soil disturbance on the structure of temporary ponds community, and their mechanisms of resilience. Under the scope of these mechanisms, we will assess the contribution of seed bank by regrowth of buried seeds, vegetative propagules growth via clonal propagation and dispersion of propagules. Soil disturbance has a biotic effect on competition giving a chance to competitively inferior species.

Seed dispersal study is essential to understand the population dynamics, which is fundamentally important to support the conservation and management of mangrove ecosystem. A laboratory study was conducted to investigate the propagule dispersal properties of two important mangrove species in Malaysia, Avicennia marina and Rhizophora apiculata. Propagules of both species were collected from the wild and released into the salinity treatments of 0, 10, 20 and 30 ppt. The dispersal properties of the propagules were observed for 60 days. In the saltwater, A. marina propagules showed high viability rate, always buoyant and developed roots and shoots rapidly while R. apiculata propagules also presented high viability rate, but their buoyancy depended on salinity and they had slower growth rate. Both species developed poorly in the freshwater especially those of A. marina. Overall, the propagule dispersal properties were significantly different between species and between freshwater and saltwater. A. marina propagules possess greater attributes to be dispersed in open coast while R. apiculata propagules are more adapted to the inland areas. The dispersal potentials of both species were found corresponded to their natural distributions in the west coast of Peninsular Malaysia. This supports the notion that propagule dispersal is one of the determinants of species distribution and abundance. [ABSTRACT FROM AUTHOR]

The application of plant factory with artificial lighting (PFAL) for producing strawberry transplants (S-PFAL) was recently introduced due to the capacity for high quality and year-round transplant production. To achieve greater efficiency with this system, it is essential to select lighting sources that have a suitable spectrum for runner plant propagation. This study was conducted to investigate the effects of the light spectrum of white light-emitting diodes (LEDs), which have a different correlated color temperature compared with that of white fluorescent lamps, on the growth of strawberry (Fragaria × ananassa Duch. cv. Maehyang) propagules and runner plants in a PFAL. Uniform propagules with one fixed runner each were placed into a PFAL for transplant production and were grown under either warm-white LEDs (WWL), mint-white LEDs (MWL), or cool-white fluorescent lamps (CWF) for 21 days. The propagules in the MWL treatment group had the greatest number of leaves, leaf area, top/root dry weight ratio and number of newly formed runners per propagule among the treatments. The dry weight of the newly formed runners of each propagule was also greatest after MWL treatment, whereas it was lowest after CWF treatment. However, there was no significant difference in the growth parameters of the runner plants among the three treatments. The photosynthetic photon efficacy of WWL and MWL was 5.40 µmol s− 1 W− 1, which was 62.6% higher than that of CWF (3.38 µmol s− 1 W− 1). The dry weight efficacies of the MWL, WWL, and CWF treatments were 23.5, 22.1, and 10.0 g kWh− 1, respectively. These results indicate that MWL with high photosynthetic photon efficacy can have positive effects on the runner formation and growth of strawberry propagules and can replace cool-white fluorescent lamps in an S-PFAL. [ABSTRACT FROM AUTHOR]

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Climate change and nutrient enrichment are two phenomena impacting coastal ecosystems. In coastal wetlands, mangroves in temperate–tropical ecotones are encroaching on adjacent saltmarshes, a pattern that is primarily attributed to warmer winter temperatures. Climate change is also expected to increase the vulnerability of coastal wetlands to eutrophication, and increases in nutrient availability may further mediate the rate of mangrove expansion. We investigated the consequences of nutrient enrichment on coastal wetlands in the mangrove–saltmarsh ecotone near the temperate edge of mangrove distribution along the northeast coast of Florida. We tested the hypothesis that nutrient enrichment enhances the ongoing, climate-driven expansion of mangroves into areas historically dominated by saltmarshes by increasing mangrove growth and cover, allowing them to outcompete and overgrow adjacent saltmarsh plants. We manipulated nitrogen (N) and phosphorus (P) availability and measured the effects on growth, cover, diversity, leaf traits, and nutrient dynamics of Avicennia germinans. We found that A. germinans shrubs growing in the saltmarsh–mangrove ecotone in northern Florida grew taller, increased their canopies, and had higher reproductive output when enriched with N compared to control plants and P-enriched plants. Nutrient enrichment did not alter Sarcocornia perennis growth and increased Batis maritima height but did not alter density or biomass. Nitrogen addition caused an increase in A. germinans cover and decrease in B. maritima cover and Simpson's index of diversity, suggesting that N enrichment, an ongoing phenomenon, can hasten the invasion of mangroves into saltmarshes by favoring mangrove growth and reproduction without significantly enhancing saltmarsh plant growth. [ABSTRACT FROM AUTHOR]

Increasing ocean temperatures associated with ongoing climate change have resulted in regional reductions in the cover of live coral and increasing concerns that coral reefs will be overgrown by macroalgae. The likelihood of macroalgal overgrowth will, however, depend on the thermal sensitivities of the macroalgae themselves. We exposed recently settled propagules of the common canopy-forming macroalga Sargassum swartzii and adult thalli of three species of Sargassum (S. swatzii, S. cristaefolium, S. polycystum) to three experimental temperatures: ambient, + 2 °C, and + 3.5 °C, reflective of summer minimum, mean, and maximum temperatures for the region. Growth and survival of Sargassum swartzii propagules were assessed over 48 days, and the growth, physical toughness, elemental composition, and susceptibility to herbivory of adult thalli were assessed after short-term exposure (2-weeks) to experimental temperatures. Growth and survival of S. swartzii propagules were reduced by 43% and 84%, respectively, when cultured at the elevated (+ 3.5 °C) temperature compared to ambient temperature. Similarly, elevated temperature resulted in a 17–49% decline in the growth of adult Sargassum thalli relative to controls. Susceptability of S. swartzii and S. cristaefolium to herbivory (i.e. mass removed by herbivores) was 50% less for thalli cultured at elevated (+ 3.5 °C) compared to ambient temperature, but this pattern was not related to changes in the physical or chemical properties of the thalli as a result of elevated temperature. The negative effects of elevated temperatures on the growth and survival of both Sargassum propagules and adult thalli will likely restrict the capacity of Sargassum, and potentially other macroalgae, to establish in new areas, and may also threaten the persistence of existing macroalgal meadows under future ocean temperatures. The thermal sensitivities of tropical Sargassum, together with those of corals, suggest ongoing ocean warming may lead to novel reef ecosystems that are low in both coral cover and macroalgal cover. [ABSTRACT FROM AUTHOR]

The functional role, relative importance, and the spatial and temporal parameters of different vector species, which underpin the passive dispersal (zoochory) of organisms (or their propagules), are frequently poorly understood. Accordingly, a conceptual framework capable of providing a rigorous and unified assessment for the dispersal capacity of vector species is required. Here, we propose and apply a series of novel metrics, the Dispersal Potential (DP), the Relative Dispersal Potential (RDP), and the Combined Dispersal Potential (CDP), to predict and classify likely dispersal and vector importance. In essence, DP = Np × Tv, whereby Np is the per capita propagule load (e.g., mean, minimum, or maximum abundance) or species richness of propagules carried per individual vector species, while Tv is the total number of possible vectors (e.g., individuals of a single species at a source site, local scale abundances, or entire continental populations). Further, the ratio based metric RDP allows for DP comparison between species, while the CDP accumulates the DP of a variety of vector species. An additional Relative CDP (RCDP) metric facilitates comparison between the CDP for multiple vectors to that of one or more additional vectors. The proposed metrics can also be used to assess intraspecific differences (e.g., ontogeny). Accordingly, we examine a variety of case studies and present calculations to ascertain the usefulness of our proposed metrics. Overall, the metrics can be used to quantify and rank the prominence of different dispersers that facilitate biological connectivity. Finally, we argue that adoption of these metrics and variants thereof, will provide a more realistic measure of species' functional roles than examination of interaction intensities alone, which will enhance understanding of zoochory within and across dispersal networks.

Paraphysoderma sedebokerense (P. sedebokerense) (Blastocladiomycota) is a facultative pathogenic chytrid that causes irreversible damage to some green microalgae. Specific attacks leading to culture collapse under different conditions have only been described in the lucrative microalga Haematococcus pluvialis (H. pluvialis), while generating biomass for ketocarotenoid astaxanthin production, both indoors and outdoors. In order to manage the infection, parasite propagules (zoospores/amoeboid swarmers), the initiators of the disease, must be studied. Until now, no report on isolated P. sedebokerense propagules has been published. Here, we report on a reproducible method for the stimulation of P. sedebokerense propagule release and their isolation from fungal cultures in synthetic media and infected H. pluvialis cultures, and we further studied their development under different conditions. The isolated propagules featured different spore morphotypes, with coatless spherical spores and amoeboid swarmers being the most dominant in the first pulse of propagule release in both cultures. Inoculating the pure propagules with the host, in both the presence and absence of nitrogen, resulted in epidemic development in both green and red cells; however, in red cells, the epidemic developed more quickly in the presence of nitrogen. Biologically non-active autoclaved host cells were used to distinguish the initial stages of recognition from more progressive stages of the epidemics; on these cells, propagules encysted but did not develop further. These results prove the existence of heat-stable recognition sites on the host and an obligatory signal transduction from the host to support fungal cyst development. The propagule isolation method described herein is a breakthrough that will enable researchers to study the influence of different substances on the propagules, specifically as the initiators of the infection, and thus assist in the management of chytrid diseases. Moreover, it will be useful in studying host-parasite recognition and, therefore, will increase our understanding of the multiple chytrid infections found in nature.

Straw and reed are natural local insulation- and construction materials, which properties allow them to replace energy intensive building materials. In general, straw and reed as building materials are considered harmless to the environment and human health. Unfortunately, the use of these materials may bring about mould growth in buildings which may result in different diseases (for example irritation of eyes, nose and throat, allergic rhinitis, conjunctivitis, and asthma) in people with weaker immune systems. No research has been carried out on the topic of microbiological community in straw and reed houses in climatic conditions similar to Estonia, although buildings made of natural materials are becoming more and more popular. The aims of the study were to investigate the indoor climate of buildings with straw and reedbale walls and to determine the factors influencing indoor air quality. In order to fulfil the set aim: (1) air quality was tested in the bedrooms of the studied houses, and the microbial species in air and walls were determined; (2) the indoor air quality parameters (CO2, RH%, and temperature) in air and at two different heights in the walls were measured. The results enable to conclude that the walls of straw or reed-bale house are suitable in Estonian climatic conditions, which as a result of professional design, usage of materials suitable for building, and high-quality craftsmanship provides a healthy and environmentally friendly housing. [ABSTRACT FROM AUTHOR]

Black foot disease, caused by Ilyonectria liriodendri and Dactylonectria macrodidyma, is a significant disease of grapevines both in New Zealand and worldwide. The aim of this study was to determine the pathogenicity of New Zealand I. liriodendri and D. macrodidyma isolates in two grapevine rootstocks as callused and rooted propagation material. Three isolates each of I. liriodendri and D. macrodidyma, all infected callused and root-wounded grapevine rootstock plants (varieties '101–14' and '5C'). Isolates from each species caused high disease incidences and severities at both 1 and 5 cm above the stem base. There were no significant differences in disease incidence or severity between rootstocks '101–14' and '5C'. However, vines arising from callused rootstock had significantly higher disease incidence and severity compared with rooted vines. Conidia caused greater disease incidence and severity compared with chlamydospores and mycelium. A novel threshold propagule experiment with I. liriodendri propagules determined that disease incidence and severity at the stem base were significantly affected by the concentration of the propagules rather than the propagule type. Root dry weights significantly differed between I. liriodendri and D. macrodidyma isolates but not between species. Root dry weights were higher with callused versus rooted vines, with mycelium versus chlamydospores or conidia, and with propagule concentration rather than propagule type. Shoot dry weights were significantly higher for I. liriodendri compared with D. macrodidyma species, rooted versus callused vines and '101–14' compared with '5C' rootstocks. The results of the study has confirmed that both I. liriodendri and D. macrodidyma were capable of infecting grapevines through wounded roots or callused basal ends, indicating that these pathogens are capable of invading grapevines either in nurseries or in vineyards. [ABSTRACT FROM AUTHOR]

The present research was done at the semi rustic seedbed "La Campanita" which belongs to the Cooperative Basic Unit of Agricultural Production of the Urban Agricultural Company in Cumanayagua municipality with aims of evaluating different proportions of soil, sand, organic matter and zeolita in the substrate for the seedling production of Acerola (Malpighia emarginata DC) by mean of cuttings, and determine the most effective combination among these components. The vegetal material used was selected according with the requirements and recommendations of technical instructions for the production of fruit trees from cuttings. The experiment was developed under semi - controlled lighting conditions and the experimental design was a random block with 6 treatments and 4 replications. The results indicated the feasibility to produce Acerola seedlings with the use of different proportions of soil, sand, organic matter and zeolite. The best response was found in the variant composed of 50% organic matter, 25% soil, 25% zeolite and surface coverage of zeolite, with 88% of live stakes and a better behavior in the quantity and length of roots emitted. All the variants used showed budding of axillary buds and rooting. [ABSTRACT FROM AUTHOR]

Paraphysoderma sedebokerense (P. sedebokerense) (Blastocladiomycota) is a facultative pathogenic chytrid that causes irreversible damage to some green microalgae. Specific attacks leading to culture collapse under different conditions have only been described in the lucrative microalga Haematococcus pluvialis (H. pluvialis) , while generating biomass for ketocarotenoid astaxanthin production, both indoors and outdoors. In order to manage the infection, parasite propagules (zoospores/amoeboid swarmers), the initiators of the disease, must be studied. Until now, no report on isolated P. sedebokerense propagules has been published. Here, we report on a reproducible method for the stimulation of P. sedebokerense propagule release and their isolation from fungal cultures in synthetic media and infected H. pluvialis cultures, and we further studied their development under different conditions. The isolated propagules featured different spore morphotypes, with coatless spherical spores and amoeboid swarmers being the most dominant in the first pulse of propagule release in both cultures. Inoculating the pure propagules with the host, in both the presence and absence of nitrogen, resulted in epidemic development in both green and red cells; however, in red cells, the epidemic developed more quickly in the presence of nitrogen. Biologically non-active autoclaved host cells were used to distinguish the initial stages of recognition from more progressive stages of the epidemics; on these cells, propagules encysted but did not develop further. These results prove the existence of heat-stable recognition sites on the host and an obligatory signal transduction from the host to support fungal cyst development. The propagule isolation method described herein is a breakthrough that will enable researchers to study the influence of different substances on the propagules, specifically as the initiators of the infection, and thus assist in the management of chytrid diseases. Moreover, it will be useful in studying host-parasite recognition and, therefore, will increase our understanding of the multiple chytrid infections found in nature. [ABSTRACT FROM AUTHOR]

Abstract Pineapple is one of the most important fruits, with large production in tropical and subtropical regions and great appreciation by consumers all over the world. The pineapple plant has many specific morphological, anatomical and physiological characteristics that determine crucial aspects of pineapple crop management, such as flower induction, water use and vegetative methods of propagation. The use of sexual reproduction of pineapple is restricted to breeding purposes carried out by research institutes looking for new hybrids with improved agronomic characteristics. Seeds are only produced if cross pollination among varieties occurs. Commercially pineapple has to be propagated by vegetative material, an asexual reproduction, without new combinations of genes. Some types of propagules are naturally produced by the plants and called conventional planting material. Its availability and quality depend on many factors, especially cultivar and environment. Management techniques of this material have been continuously developed and will be addressed. In addition to the conventional planting material, which in many situations is not sufficient to assure expansion or at least maintenance of the cultivated area, several other methods of vegetative propagation of pineapple have been studied and made available along the last decades and will also be discussed, involving techniques of stem sectioning, apical growing point gouging and chemical treatment for transformation of flowers into plantlets. Stem sectioning has been especially interesting, as it is mostly done using plant residues available at low cost, and is a rather simple method suited for multiplication and production of disease-free planting material in nurseries. Gouging and chemical treatment are less practiced, but can be applied in ratoon crops, thereby avoiding the loss of the first cycle fruit. Chemical treatment usually results in rather small plantlets, that must be further grown in nurseries before planting them in the field. And finally micropropagation will also be focused, as in vitro production of plantlets is a very important method of multiplication of new pineapple varieties, but this method yet has not been transformed into a common commercial way of pineapple propagation due to the final high cost and to the still high risks of incidence of somaclonal variations among the plantlets produced.

Lasiococca comberi (Euphorbiaceae), a threatened forest tree species of Eastern Ghats of India, has inherent problems of seed germination and seedling establishment in nature. To overcome this problem and to facilitate large-scale production of planting materials for reintroduction programmes to augment the wild populations of this threatened species, an attempt has been made to develop an efficient vegetative propagation method through air layering. Three types of auxins such as indole-3-butyric acid (IBA), indole acetic acid (IAA) and naphthalene acetic acid (NAA) in different concentrations and combinations were used to induce rooting in stems of healthy mature trees in forests during rainy season. Air-layered branches treated with 5000 ppm IBA resulted in maximum percentage of rooting (95.23 ± 7.6%), maximum number (14.50 ± 1.9) and length of roots (12.5 ± 1.0 cm), minimum days taken for root initiation (18.5 ± 0.5 days) and highest percentage of survival of air-layered propagules. The well-rooted branches were transplanted in polybags under mist house conditions for acclimatisation and hardening before field planting. The result of the present study can be useful for mass production of large-sized planting materials of this threatened species from mature trees in a relatively shorter period at a reasonable cost for reintroduction to natural habitats as a part of species recovery programme. [ABSTRACT FROM AUTHOR]

Dipterocladia yongdeokkoi sp. nov. was collected at depths of 6-15 m at three locations at Jeju Island, Korea: Biyangdo, Hado and Shinchang. All plants were vegetative without reproductive structures. For two years in laboratory culture, plants were consistently vegetative. Cultured plants formed single-celled diaspores and multicellular propagules that grew into mature plants. Dipterocladia yongdeokkoi is distinguished by its flattened thallus arising from a thick, cylindrical stipe, compressed axes, irregular branches and alternately pinnate determinate adventitious laterals and pseudolaterals. Analyses of mitochondrial cox1, plastid rbcL, and nuclear small subunit (SSU) sequences support the monophyly of Dipterocladia and the distinctness of D. yongdeokkoi from other species of Dipterocladia. [ABSTRACT FROM AUTHOR]

Black foot disease of grapevines is a major economic issue for the viticulture industry, with several Dactylonectria and Ilyonectria species identified as causal agents worldwide. This study aimed to confirm the pathogenicity of an Ilyonectria pseudodestructans isolate recovered from a symptomatic grapevine in a nationwide survey. An initial pot experiment inoculated callused and root-wounded grapevine propagation material of varieties '101- 14' and '5C' with I. pseudodestructans conidia. The second pot experiment compared the pathogenicity of I. pseudodestructans conidial, chlamydospore and mycelial inocula. Disease incidence, severity and root and shoot dry weights were determined after 4-5 months of growth. Ilyonectria pseudodestructans was recovered from inoculated plants resulting in higher disease incidence and severity compared with the uninoculated control. Disease severity and incidence was higher for callused compared to rooted propagation material, but did not differ between grapevine varieties. Conidial inoculum caused greater disease incidence and severity compared with chlamydospore and mycelial inocula. Ilyonectria pseudodestructans propagules infected grapevine plant material via the callused basal ends or wounded roots, indicating this species is a potentially important pathogen of grapevines both in nurseries and vineyards. [ABSTRACT FROM AUTHOR]

In the production chain of the potato, the production of "seed" tubers is insufficient, so the objective of the work was to evaluate the effect of Quitomax® in the production of seed potato tubers. The plantations was carried out in the years 2015, 2016 and 2017, by means of a random block design with three replicates and three treatments: a control without application and foliar application of two chitosan of different molar mass, it was applied at a rate of 300 mL ha-1, at 30 and 50 days after planting (DAP). The harvest was evaluated at 75 DAP, but in year 2017, at 65 DAP too. All the plants corresponding to two furrows of each treatment were taken in each plot and the tubers were separated by size, weighed and counted. The number of stems and the number of tubers per plant ware evaluated, in addition to estimating yield in t ha-1. A double-ranking ANOVA were used to processing data and the Duncan's test to compare the means. No effects with respect to the control in the number of stems and the number of tubers were detected. The size and distribution of tuber ensured a greater amount of the same in the calibers used as seed in both chitosan, but this result was reached earlier than in the control, the yield was higher in plants sprayed with the bioproduct. [ABSTRACT FROM AUTHOR]

Bruguiera sexangula (Lour) Poir., a threatened mangrove tree, was inoculated with beneficial microbes in a nursery to assess any improvements in growth and biomass. From soil samples from the rhizosphere of B. sexangula in a mangrove forest in Panangadu of Kerala India, nitrogen-fixing bacteria Azotobacter chroococcum and Azospirillum brasilense were isolated. The phosphate-solubilising bacterium Bacillus megaterium and potassium-mobilizing bacteria Frateruria aurantia were also isolated and cultured on suitable media. Later, ripe propagules of B. sexangula were collected from matured trees and raised in sterilized soil bags (13 × 25 cm) containing sterilized soil and sand (2:1 ratio). The cultured beneficial microbes were propagated and used to inoculate the ripe propagules of B. sexangula and maintained in the nursery for 6 months. After 6 months, growth and biomass of the inoculated propagules were greater than for the uninoculated control propagules. Shoot length, number of leaves, stem girth and root length were also significantly greater than in the controls. This study showed that the mangrove-specific beneficial microbes influenced the growth of B. sexangula in the nursery and will help in the establishment of B. sexangula in degraded mangrove forests. [ABSTRACT FROM AUTHOR]

Early life stages of marine organisms are predicted to be vulnerable to ocean acidification. For macroalgae, reproduction and population persistence rely on spores to settle, adhere and continue the algal life cycle, yet the effect of ocean acidification on this critical life stage has been largely overlooked. We explicitly tested the biomechanical impact of reduced pH on early spore adhesion. We developed a shear flume to examine the effect of reduced pH on spore attachment time and strength in two intertidal rhodophyte macroalgae, one calcified (Corallina vancouveriensis) and one noncalcified (Polyostea robusta). Reduced pH delayed spore attachment of both species by 40%–52% and weakened attachment strength in C. vancouveriensis, causing spores to dislodge at lower flow‐induced shear forces, but had no effect on the attachment strength of P. robusta. Results are consistent with our prediction that reduced pH disrupts proper curing and gel formation of spore adhesives (anionic polysaccharides and glycoproteins) via protonation and cation displacement, although experimental verification is needed. Our results demonstrate that ocean acidification negatively, and differentially, impacts spore adhesion in two macroalgae. If results hold in field conditions, reduced ocean pH has the potential to impact macroalgal communities via spore dysfunction, regardless of the physiological tolerance of mature thalli. [ABSTRACT FROM AUTHOR]

Background: Globally, invasive amphibians are known for their environmental and social impacts that range from poisoning of local fauna and human populations to direct predation on other amphibians. Although several countries on most continents have had multiple introductions of many species, southern Africa appears to have escaped allochthonous introductions. Instead, it has a small number of domestic exotic species that have rapidly expanded their ranges and established invasive populations within South Africa. Objectives & methods: We used the literature to provide a historical overview of dispersal by some of the world’s major invasive amphibians, give examples of species that are commonly moved as stowaways and discuss historical and current amphibian trade in the region. In addition, we give an overview of new South African legislation and how this is applied to amphibian invasions, as well as providing updates on the introduced populations of three domestic exotics: Hyperolius marmoratus, Sclerophrys gutturalis and Xenopus laevis. Results: We show that frogs are mainly moved around southern Africa through ‘jump’ dispersal, although there are a number of records of ‘cultivation’, ‘leading-edge’ and ‘extreme long-distance’ dispersal types. Important pathways include trade in fruit and vegetables, horticultural products and shipping containers. Conclusion: We suggest that southern Africa is becoming more vulnerable to amphibian invasions because of an increase in trade, agricultural and domestic impoundments as well as global climate change. Increasing propagule pressure suggests that preventing new introductions will become a key challenge for the future. Currently, trade in amphibians in the region is practically non-existent, suggesting potential for best practice to prevent importation of species with high invasion potential and to stop the spread of disease.

Aim Connectivity assessments are crucial to large-scale conservation planning, in particular for establishing and monitoring connected networks of marine protected areas ( MPAs). Using biophysical modelling and genetic analyses, we assessed potential and realized connectivity among MPA populations of a benthic foundation species, the Mediterranean endemic seagrass Posidonia oceanica. Location Adriatic and Ionian seas (central Mediterranean). Methods We assessed potential and realized connectivity among eight P. oceanica meadows, mostly located in MPAs. Potential connectivity was assessed over a time horizon of 10 years via an individual-based biophysical model whose physical component relies on fine-scale spatio-temporal ocean circulation fields. Genetic assessments of realized connectivity were carried out by means of a set of 14 neutral microsatellite loci, as well as a larger dataset of 19 loci including outlier loci that did not conform to expectations under neutrality. Results Our findings point out a relatively high potential connectivity through long-range dispersal of floating fruits. Genetic connectivity analyses show a complex scenario with an apparent lower realized connectivity. The P. oceanica meadow within Torre Guaceto MPA ( TOG), a well-enforced MPA within our study area, showed one of the highest levels of genotypic richness, indicative of high levels of sexual reproduction and/or recruitment of foreign genotypes. Both biophysical modelling and population genetics indicate that TOG is important to ensure the viability of the species at the local scale, and does likely play a key role as a source of propagules for the whole Adriatic area. Main conclusions Our results show that realized dispersal does not necessarily match with the potential for dispersal. Still, both genetic and physical connectivity analyses show good agreement in identifying hotspots of connectivity. Such information can guide management of networks of MPAs and advance conservation of marine biodiversity. [ABSTRACT FROM AUTHOR]

Chrysophyllum is the second largest genus of Sapotaceae, with 81 species distributed in the neotropics. Little data are found in the literature regarding the morphology of seedlings and the early development of this genus. This study aims to morphologically characterize the fruit, seeds and seedlings of Chrysophyllum rufum Mart. Fruits were collected from individuals present in two fragments of the Atlantic Forest, Pernambuco. A sample of 100 seeds and 100 fruits was randomly selected to obtain the morphological data. The seeds were sown in plastic trays in a greenhouse. The fruits are bacoid, obovoid and globose with one or two functional seeds per fruit. The seeds are obovate, with the shape of the hilum ranging from elliptical transverse to oblong transverse. The embryo is cotyledonar, with a spatulated form. The cotyledons are foliaceous and whitish-translucent. The endosperm is abundant and whitish. Germination is epigeal, phanerocotylar and unipolar. The seedling has different characteristics than those of the adult individual, such as the shape and leaf consistency, type of leaf margin, type of venation variation, number of pairs of secondary veins, trichome coloring and abundance of latex. [ABSTRACT FROM AUTHOR]

The widespread loss of wetlands due to agricultural intensification has been highlighted as a major threat to aquatic biodiversity. However, all is not lost as we reveal that the propagules of some aquatic species could survive burial under agricultural fields in the sediments of ‘ghost ponds’ - ponds in-filled during agricultural land consolidation. Our experiments showed at least eight aquatic macrophyte species to germinate from seeds and oospores, following 50–150 years of dormancy in the sediments of ghost ponds. This represents a significant proportion of the expected macrophyte diversity for local farmland ponds, which typically support between 6 and 14 macrophyte species. The rapid (< 6 months) re-colonisation of resurrected ghost ponds by a diverse aquatic vegetation similarly suggests a strong seed-bank influence. Ghost ponds represent abundant, dormant time capsules for aquatic species in agricultural landscapes around the globe, affording opportunities for enhancing landscape-scale aquatic biodiversity and connectivity. While reports of biodiversity loss through agricultural intensification dominate conservation narratives, our study offers a rare positive message, demonstrating that aquatic organisms survive prolonged burial under intensively managed agricultural fields. We urge conservationists and policy makers to consider utilizing and restoring these valuable resources in biodiversity conservation schemes and in agri-environmental approaches and policies. [ABSTRACT FROM AUTHOR]

Soil seed bank is the main store of propagules available for maintenance, regeneration and perpetuation of the rangeland plant community. The composition and distribution of such reservoir can be changed by the practice of roller-chopping. The objective of this work was to evaluate the effect of selective roller-chopping on the germinable grass seeds bank from a calden forest region. In line with that, collection of soil samples was performed on both roller-chopped and untreated rangeland areas considering for each of them the following sampling sites: (1) patches composed by only herbaceous plants (open vegetation), (2) patches composed by a mix of herbaceous and woody plants (closed vegetation) and (3) patches composed by only woody plants. Composition and density of grasses of the seed reservoir were determined by the method of direct germination or seedling emergence. For forage species found in this survey, a higher density of seedlings was observed in samples from areas under roller-chopping and of open vegetation. Regarding non-forage species, in contrast, the maximum number of seedlings was observed in samples from areas that were not treated by rollerchopping. The effects of selective rollerchopping on soil seed reservoir will depend on the plant species under consideration,the characteristics of the vegetation patch, the paddock history of use and the rangeland management after the application of roller-chopping [ABSTRACT FROM AUTHOR]

Obtaining reliable and representative mushroom production data requires time-consuming sampling schemes. In this paper, we assessed a simple methodology to detect mushroom emergence by trapping the fungal spores of the fruiting body community in plots where mushroom production was determined weekly. We compared the performance of filter paper traps with that of funnel traps and combined these spore trapping methods with species-specific quantitative real-time PCR and Illumina MiSeq to determine the spore abundance. Significantly more MiSeq proportional reads were generated for both ectomycorrhizal and saprotrophic fungal species using filter traps than were obtained using funnel traps. The spores of 37 fungal species that produced fruiting bodies in the study plots were identified. Spore community composition changed considerably over time due to the emergence of ephemeral fruiting bodies and rapid spore deposition (lasting from 1 to 2 weeks), which occurred in the absence of rainfall events. For many species, the emergence of epigeous fruiting bodies was followed by a peak in the relative abundance of their airborne spores. There were significant positive relationships between fruiting body yields and spore abundance in time for five of seven fungal species. There was no relationship between fruiting body yields and their spore abundance at plot level, indicating that some of the spores captured in each plot were arriving from the surrounding areas. Differences in fungal detection capacity by spore trapping may indicate different dispersal ability between fungal species. Further research can help to identify the spore rain patterns for most common fungal species. IMPORTANCE Mushroom monitoring represents a serious challenge in economic and logistical terms because sampling approaches demand extensive field work at both the spatial and temporal scales. In addition, the identification of fungal taxa depends on the expertise of experienced fungal taxonomists. Similarly, the study of fungal dispersal has been constrained by technological limitations, especially because the morphological identification of spores is a challenging and time-consuming task. Here, we demonstrate that spores from ectomycorrhizal and saprotrophic fungal species can be identified using simple spore traps together with either MiSeq fungus-specific amplicon sequencing or species-specific quantitative real-time PCR. In addition, the proposed methodology can be used to characterize the airborne fungal community and to detect mushroom emergence in forest ecosystems. [ABSTRACT FROM AUTHOR]

Contribution of Pheidole fallax and Ectatomma ruidum (Hymenoptera: Formicidae) to the dispersion and germination of seeds in rehabilitated areas of the Cerrejón coal mine, Colombia. Seed dispersal is a key process in the re-establishment of vegetation on reclaimed lands. The aim of this study was to determine the contributions of the ant species Ectatomma ruidum and Pheidole fallax to seed dispersal and germination on reclaimed lands in the Cerrejón coal mine, Colombia. Four 6 x 40 m plots were installed in each area, in which the number of nests by species was counted and distances between closest nests of each species were measured. Five of the nests counted were chosen for seed extraction, and a nearby control sample was taken from each nest. In total, 295 nests were counted: 59 nests during the dry season and 236 nests during the rainy season, of which 84 belonged to P. fallax and 211 belonged to E. ruidum. A total of 21 304 seeds were found in nests and control samples, of which 19 349 were obtained from P. fallax nest refuse, and 318 were obtained from E. ruidum nests; 597 seeds were found in control samples. The number of seeds extracted from nests was significantly higher than the number of seeds removed from control samples. There was a significant difference between the number of seeds removed by P. fallax and the number of seeds removed by E. ruidum. The seed germination percentage from nests was higher than the percentage from seeds in control samples. In the case of P. fallax, the germination percentage was lower in control samples and higher in nests and refuse. The results suggest that the ant species E. ruidum and P. fallax may contribute to seed dispersal and re-establishment of vegetation in areas where they were found. These ants may thus significantly contribute to restoration processes in areas degraded by mining. [ABSTRACT FROM AUTHOR]

The coastal saltmarshes in China have been seriously degraded and artificial restoration strategies have become one of the primary measures to protect the coastal habitats. In this study, we investigated efficient restoration techniques for native saltmarsh plants in vacant habitats within the project area of the Ecological Control of Spartina alterniflora and Improvement of Birds Habitats in the Shanghai Chongming Dongtan Bird National Nature Reserve in the Yangtze Estuary. Through field and pilot experiments, we analyzed the effects of propagule types and transplanting methods on the restoration efficiency of Scirpus mariqueter , a dominant saltmarsh species in the Yangtze Estuary. We further evaluated the cost and efficiency of various restoration strategies. Our results indicated that: 1) The corm seedlings of S. mariqueter had higher flood tolerance, and were suitable for use in the habitats with higher environmental heterogeneity. 2) Across the four treatments for S. mariqueter restoration, the most economically efficient treatment was to transplant low-density corm seedlings without sediment, with an investment cost of approximately ￥10100 per hectare. The costs were ￥41100, ￥30000, and ￥120100 per hectare for high-density without sediment, low-density with sediment, and high-density with sediment restoration, respectively. 3) After nearly 5-yr efforts, the S. mariqueter community of Plot C3 in project area had achieved a coverage of over 60%, marking a relatively successful large-scale field restoration. This study could provide the foundation and support for large-scale coastal saltmarsh restoration projects.

Objetivou-se, no presente trabalho, estudar a resposta produtiva da mandioquinha-salsa 'Amarela de Carandaí', propagada por mudas grandes-MG (22,1 g); médias-MM (14,1 g); pequenas-MP (9,7 g) e muito pequenas-MMP (5,7 g) e cultivada em canteiros com duas-2F e três fileiras-3F de plantas. Foram feitas colheitas aos 211 e 239 dias após o plantio-DAP. Todas as características avaliadas nas plantas, nas duas colheitas, foram influenciadas de forma variável pela interação tamanho das mudas e número de fileiras no canteiro. As maiores alturas das plantas foram daquelas do tratamento MP3F, nas duas épocas de colheita, mas, as colhidas aos 211 DAP (35,64 cm) apresentaram 4,50 cm a mais em relação às colhidas aos 239 DAP (31,14 cm). As massas frescas de folhas foram maiores nas plantas do tratamento MG2F (23,86 t ha-1), aos 211 DAP, e as do MM3F (22,09 t ha-1), aos 239 DAP. As maiores médias de massas frescas de rebentos (8,66 t ha-1) e de coroas (5,66 t ha-1) foram obtidas aos 239 DAP, em relação às dos 211 DAP (7,19 e 4,20 t ha-1). As maiores produções de raízes comerciais (11,61 t ha-1) e de não comerciais (5,80 t ha-1) foram do tratamento MG3P, aos 211 DAP e dos tratamentos MMP2F (14,48 t ha-1) e MP3F (5,92 t ha-1), respectivamente, aos 239 DAP. As massas frescas de raízes comerciais representaram apenas 18,31% e 23,08%, aos 211 DAP e 239 DAP, respectivamente, em relação à produção total das plantas.The present research aimed to study the productive response of 'Amarela de Carandaí Peruvian carrot (Arracacia xanthorrhiza Bancroft), which was propagated by big - MG (22.1 g); medium - MM (14.1 g); small - MP (9.7 g) and very small - MMP (5.7 g) seedlings and cultivated on plots with two (2F) and three (3F) rows of plants. Harvests were accomplished at 211 and 239 days after planting (DAP). Every evaluated plant characteristics from the two harvests were diversely influenced by the interaction between the seedling sizes and the number of rows per plot. The highest height of plants were those from the MP3F treatments, for both dates of harvest, but those harvested at 211 DAP (35.64 cm) showed an extra 4.50 cm in relation to those harvested at 239 DAP (31.14 cm). Fresh matters of leaves were higher for plants from the MG2F treatment (23.86 t ha-1), at 211 DAP, and from the MM3F (22.09 t ha-1), at 239 DAP. The highest averages of fresh matters of shoots (8.66 t ha-1) and of crowns (5.66 t ha-1) were obtained from 239 DAP, in relation to those from 211 DAP (7.19 and 4.20 t ha-1). The highest yields of commercial roots (11.61 t ha-1) and non-commercial roots (5.80 t ha-1) were from the MG3F treatment, at 211 DAP and from the MMP2F (14.48 t ha-1) and MP3F (5.92 t ha-1) treatments, respectively, at 239 DAP. The fresh matter of commercial roots represented only 18.31% and 23.08%, at 211 DAP and 239 DAP, respectively, in relation to total yield of plants.

O objetivo do trabalho foi avaliar a capacidade produtiva do mangarito, cv. Comum (Xanthosoma mafaffa Schott), proveniente de rizomas-semente secundários de tamanhos diferentes, cultivados sob três ou quatro fileiras de plantas no canteiro. Os tratamentos foram constituídos pela combinação do número de fileiras de plantas no canteiro e do plantio de quatro tamanhos de rizomas-semente secundários (massa fresca, em grama, e diâmetro, em milímetro, respectivamente, de T1= 2,96 e 8,77, T2= 1,33 e 6,05, T3= 1,13 e 5,68 e T4= 0,78 e 4,83, médias de 300 rizomas de cada tamanho), como fatorial 2 x 4, no delineamento experimental de blocos casualizados, com quatro repetições. A colheita foi realizada aos 300 dias após o plantio. As produções de massa fresca dos rizomas, total, rizomas-mãe e rizomas-filho, foram influenciadas significativamente pela interação número de fileiras de plantas no canteiro e tamanho dos rizomas-semente. As médias dos diâmetros, comprimentos e massas frescas dos rizomas-mãe (43,13 mm; 21,36 mm e 13,21 g) e dos rizomas-filho, nas classes grande (37,15 mm; 18,57 mm e 9,60 g), média (30,71 mm; 14,18 mm e 4,14 g) e pequena (19,72 mm; 9,46 mm e 1,07 g), apresentaram variações significativas dependentes da interação entre número de fileiras no canteiro e tamanho de rizomas-semente, dentro de cada característica avaliada nos rizomas. As maiores produções totais (11,48 t ha-1) e de rizomas comerciais (4,51 t ha-1) foram do tratamento três fileiras de plantas e rizomas-semente T1 e as de rizomas não-comerciais foram do tratamento quatro fileiras de plantas e rizomas-semente T2 (7,41 t ha-1). As menores produções totais (0,96 t ha-1), líquida (0,86 t ha-1) e de rizomas comerciais (0,60 t ha-1) e não-comerciais (0,26 t ha-1) foram do tratamento três fileiras de plantas e plantio de rizomas T4.The objective of this work was to evaluate yield capacity of Comum tannia (Xanthosoma mafaffa Schott) from secondary seed-rhizomes of different sizes and cultivated under three or four rows of plants per plot. Treatments were established by the combination of the number of rows of plants per plot and by the planting of four sizes of secondary seed-rhizomes (fresh mass, in gram, and diameter, in millimeter, respectively, of T1 = 2.96 and 8.77; T2 = 1.33 and 6.05; T3 = 1.13 and 5.68 and T4 = 0.78 and 4.83, average of 300 rhizomes of each size), as 2 x 4 factorial scheme in a randomized block experimental design with four replications. Harvest was done on 300 days after planting. Yields of fresh mass of rhizomes, total, corms and cormels were influenced significantly by number of rows per plot/size of seed-rhizomes interaction. Average of diameters, lengths and fresh masses of corms (43.13 mm; 21.36 mm and 13.21g) and cormels, from big (37.15mm; 18.57 mm and 9.60 g), medium (30.71 mm; 14.18 mm and 4.14 g) and small (19.72 mm; 9.46 mm and 1.07 g) classes, showed variations significantly which were dependent on number of rows per plot/size of seed-rhizome interaction, inside each evaluated characteristic of rhizomes. The highest total yields (11.48 t ha-1) and commercial rhizomes (4.51 t ha-1) were from the treatment with three rows of plants and T1 seed-rhizome and the highest yields of non-commercial rhizomes were from the treatment with four rows of plants and T2 seed-rhizome (7.41 t ha-1). The most low total yields (0.96 t ha-1), net (0.86 t ha-1), commercial (0.60 t ha-1) and of non-commercial (0.26 t ha-1) were from the treatment with three rows of plants and the planting of T4 rhizomes.

The recovery of the mangrove areas that have been degraded needs mangrove seedlings in large quantity. A mangrove nursery is generally located on the land close to the planting site and brackish water. The mangrove nursery by means of fresh water is an innovation in the provision of seeds. The objective of this experiment was to determine the growth of seedlings of Rhizophoraceae in fresh water based on the parameters of the number of leaves and the height of the shoots. The method of breeding utilizes fresh water and to keep the water remains available the water circulation is regulated. The results of the observations show that the number of leaves of Bruguiera gymnorrhiza has the number of pairs of leaves compared with Rhizophora apiculata dn R. mucronata. The average height of the shoots up to the age of 5 months after planting, the highest seedlings are R. mucronata seedlings. In general, mangrove nursery with fresh water can be utilized as a means for providing seedlings for rehabilitation of mangrove. [ABSTRACT FROM AUTHOR]

Long-term closure of the Kobonqaba Estuary mouth to the sea resulted in high water levels, inundation of pneumatophores and die-back of the mangroves specifically, Avicennia marina . The recovery of the mangroves was measured by assessing changes in vegetation cover and sediment characteristics along transects and all mangroves present in the estuary were described in terms of height, diameter at breast height and phenology. Measurements were made in 2011, 2012, 2013 and 2015. Surviving adult trees were producing propagules and showed that the forest would be able to regenerate if the seedlings established and were able to survive the environmental conditions. However there may be competition from salt marsh plants which increased in average cover from 0% in 2011 to 18.9% (2013) and 50% in 2015. Sediment characteristics changed over the study period with more oxic conditions in 2013 and 2015 (57.6 and 62.3 mV) compared to 2011 and 2012 (− 189 to − 148 mV) and organic matter decreased from 18.4% in 2011 to 9.8% in 2015. High initial porewater nutrient concentrations in 2013 promoted salt marsh growth. A particular sequence of events was recorded for the establishment of salt marsh in this previous mangrove habitat where stabilization of sediment by microphytobenthos and macroalgae was the key to further colonization by emergent macrophytes. [ABSTRACT FROM AUTHOR]

Anthropogenic stressors associated with climate change and shoreline development are increasingly impacting important habitats. But when multiple stressors act simultaneously, the results are often difficult to predict. Effects of multiple anthropogenic stressors and their interactions with community processes are of particular concern in estuarine habitats because of their vulnerability to anthropogenic impacts and their provision of valuable ecosystem services such as fisheries production and sediment stabilization. Two stressors, warming temperatures and reduced light availability due to suspended materials, are expected to simultaneously affect important habitats such as seagrass systems, but the impacts of these stressors may be influenced by community processes such as immigration. Immigration of propagules can alter diversity and relative species abundances, rescue populations from extinction, and modify the capacity of communities to respond to environmental conditions. Using an experimental eelgrass ( Zostera marina ) system, we examined how warming, reduced light availability (shading), and periodic immigration of crustacean grazers influenced diversity, biomass, and structure of this community. Shading generally had large effects, and reduced biomass of all primary producers but did not affect grazer biomass. Warming reduced epiphytic algal biomass but only in the absence of grazers, while it increased sessile invertebrate biomass overall. Immigration of crustacean grazers did not interact significantly with stressors, and had little effect overall. Immigration did not influence diversity of grazers, relative abundance of grazer species, or biomass of primary producers and sessile invertebrates, however, it did increase biomass of grazers. Overall, reduced light availability by shading had strong effects on primary producers, whereas warming generally had weaker effects that differed with grazer presence. Thus, our results show that the impacts of reduced light availability and warming were independent and context specific, while crustacean grazer immigration effects were minimal in this model eelgrass system. [ABSTRACT FROM AUTHOR]

Patterns of elevational distribution of alien plant species in the southern Sierra Nevada of California were used to test the hypothesis that alien plant species invading high elevations around the world are typically climate generalists capable of growing across a wide elevational range. The Sierra Nevada has been heavily impacted for more than a century and a half, first by heavy grazing up into high elevation meadows, followed by major logging, and finally, by impacts associated with recreational use. The comparative elevational patterns of distribution and growth form were compared for native and alien plant species in the four families (Asteraceae, Brassicaceae, Fabaceae, and Poaceae) that contribute the majority of naturalized aliens in the study area. The distribution of realized climatic niche breadth, as measured by elevational range of occurrence, was virtually identical for alien and native species, with both groups showing a roughly Gaussian distribution peaking with species whose range covers a span of 1500-1999 m. In contrast to alien species, which only rarely occurred at higher elevations, native species showed a distribution of upper elevation limits peaking at 3000-3499 m, an elevation that corresponds to the zone of upper montane and subalpine forests. Consistent with a hypothesis of abiotic limitations, only a few alien species have been ecologically successful invaders at subalpine and alpine elevations above 2500 m. The low diversity of aliens able to become established in these habitats is unlikely due to dispersal limitations, given the long history of heavy grazing pressure at high elevations across this region. Instead, this low diversity is hypothesized to be a function of life history traits and multiple abiotic stresses that include extremes of cold air and soil temperature, heavy snowfall, short growing seasons, and low resource availability. These findings have significant implications for resource managers. [ABSTRACT FROM AUTHOR]

Trade in live animals has been associated with populations of invasive species as well as the spread of disease. The African clawed frog,Xenopus laevis, was exported from its native region of southern Africa for use in pregnancy testing, and later for laboratory use as the model amphibian. We use historical export figures and publication records to detail the size and extent of the global trade. In addition, we explore the link between exports, scientific use, and invasive populations and chytrid outbreaks. Exports reached 400 000 animals in the first 30 years from 1940, but only 86 000 were sent outside Africa. Exports out of Africa peaked in the 1950s, while scientific publications usingXenopus laevisgrew in the 1970s, coinciding with a rise in invasive populations and chytrid outbreaks. We show a lag between exports ofXenopus laevisand a rise in invasive populations of around 15 years. Our data demonstrate the global reach of the exports ofXenopus laevisfrom South Africa, and a later, much wider distribution via the scientific network which was supplied by secondary means outside of South Africa. We contend that our data demonstrate that by 1970,Xenopus laeviswas the world’s most widely distributed amphibian: institutions in 48 countries were supplied with live colonies on all continents except Antarctica. There is some evidence linking exports and scientific studies with invasive populations, but others appear to be linked to secondary distributors of this species. [ABSTRACT FROM PUBLISHER]

Mechanisms and vectors of long-distance dispersal remain unknown for many coastal benthic species, including plants. Indications for the possibility for long-distance dispersal come from dispersal modelling and from genetic assessments, but have rarely been assessed with both methods. To this end, we assessed dispersal of the seagrass Zostera noltei , an important foundation species of the coastal zone. We investigate whether small scale seed dispersal and long-distance propagule dispersal do play a role for meta-population dynamics, using both genetic assessments based on eight microsatellite markers and physical modelling of ocean currents. Such assessments enhance our understanding of the biology and population dynamics of an important coastal foundation species. They are relevant for large scale conservation strategies as they give insights in the maintenance of genetic diversity and connectivity that may enhance resilience and resistance to stresses associated with seagrass loss. [ABSTRACT FROM AUTHOR]

The objective of this study is to verify the cutting efficiency of Eugenia involucrata seeds in seedling formation, as a way to maximize seed lots for sapling production. E. involucrata seeds were submitted to the following treatments: a) Control (uncutting seeds), b) Seeds transversely cut, with or without hilum, c) Seeds longitudinally cut, with and without hilum and germinated afterwards on germitest paper roll substrate at a temperature of 25 ° C and constant white light, with four repetitions of 25 seeds or seed fractions. The percentage of propagules with capacity to produce normal seedlings (the germination percentage) and germination speed (the Speed of Germination Index) were calculated. The uncut seeds (control) showed a higher germination percentage (72%) and speed (SGI = 0.64). The use of seed fractions was not considered an efficient method for maximizing E. involucrata seed lots, since germination was directly affected. [ABSTRACT FROM AUTHOR]

The South African coastline is just over 3000 km in length yet it covers three major biogeographic regions, namely subtropical, warm temperate and cool temperate. In this review we examine published information to assess the possible role of climate change in driving distributional changes of a wide variety of organisms around the subcontinent. In particular we focus on harmful algal blooms, seaweeds, eelgrass, mangroves, salt marsh plants, foraminiferans, stromatolites, corals, squid, zooplankton, zoobenthos, fish, birds, crocodiles and hippopotamus, but also refer to biota such as pathogens, coralline algae, jellyfish and otters. The role of pioneers or propagules as indicators of an incipient range expansion are discussed, with mangroves, zoobenthos, fishes and birds providing the best examples of actual and imminent distributional changes. The contraction of the warm temperate biogeographic region, arising from the intrusion of cool upwelled waters along the Western Cape shores, and increasingly warm Agulhas Current waters penetrating along the eastern parts of the subcontinent, are highlighted. The above features provide an ideal setting for the monitoring of biotic drivers and responses to global climate change over different spatial and temporal scales, and have direct relevance to similar studies being conducted elsewhere in the world. We conclude that, although this review focuses mainly on the impact of global climate change on South African coastal biodiversity, other anthropogenic drivers of change such as introduced alien invasive species may act synergistically with climate change, thereby compounding both short and long-term changes in the distribution and abundance of indigenous species. [ABSTRACT FROM AUTHOR]

Waterbirds are important seed dispersers and may play a vital role in maintaining connectivity among isolated aquatic communities. Whilst considerable progress has been made in our understanding of the dispersal function of waterbirds, the number of studies is still limited and is largely focused on migratory waterbirds in Europe., We present the first detailed study of seed dispersal by waterbirds in Africa. We quantified and compared endo- and ectozoochory across six waterfowl species at three widely dispersed sampling locations in South Africa and tested for differences between dispersal agents and sampling sites. We also tested for differences in the plant communities dispersed by endo- and ectozoochory. All intact and germinating propagules found in freshly collected faecal samples ( N = 313) and feather brushings ( N = 422) were counted and identified., A total of 1585 propagules from 48 plant taxa were recovered from the samples. Thirty-seven per cent of all external brushings and 27% of all faecal samples contained at least one intact propagule and 15 and 8% of the samples contained at least one germinating propagule, respectively. Sampling site had a strong influence on the presence, abundance and germination of propagules recovered from both external and faecal samples. Additionally, sympatric waterfowl showed differences in the abundance and germinability of plant propagules transported by endozoochory., The presence of at least one propagule was highest in the external samples, but propagule abundance and germination were highest in faecal samples. The community composition of propagules transported by each of these two modes was significantly different, suggesting that endo- and ectozoochory are complementary dispersal mechanisms., Our results indicate an important role for waterbirds in the dispersal of aquatic plants in Africa. While ectozoochory can be an important dispersal mechanism, its effects may be heterogeneous and unpredictable relative to endozoochory. Endozoochory appears to be the more effective and dominant mechanism. Our results also point to a high capacity for the dispersal of exotic species via both ecto- and endozoochory. [ABSTRACT FROM AUTHOR]