Abstract: Caladenia is very unusual in that it contains species that attract pollinators by two different strategies, food and sexual deception. Among the sexually deceptive species, baiting for pollinators has shown that within populations orchid species are typically pollinated by a single species of thynnine wasp. However, some wasp species can be pollinators of more than one species of orchid usually when their ranges do not overlap. There is a trend for closely related orchids to exploit wasps from the same genus, with different lineages of orchids often pollinated by different genera. Very little is known about pollination of food-deceptive Caladenia species, although it is evident they attract a suite of generalist food-seeking insects. Food-deceptive species have a higher pollination rate than do sexually deceptive species. Studies of population genetics and pollen movements are few, although they suggest a pattern of fine-scale genetic structuring within populations, owing to predominantly restricted seed dispersal and low genetic differentiation among populations as a consequence of rare long-distance seed-dispersal events. Both evolutionary and ecological research of Caladenia will greatly benefit from a better understanding of the insect species involved in pollination, their ecological requirements and the ecological and genetic consequences of food and sexual deception.

Abstract: Sesbania virgata (Cav.) Pers. is a bush, pioneer and occurs naturally in Brazil. It belongs to the Fabaceae family and it is indicated for recovery of degraded areas because of its rusticity and capacity to tolerate flooding. The present research was carried out to investigate the ability of S. virgata plants to adapt to flooding conditions. Plants containing six expanded leaves were placed in masonry tanks and were subjected to the following conditions: control (well watered), soil-waterlogging (water to the setup level of 1 cm above the soil surface – roots and parts of the stems flooded) and complete submergence (whole plant flooded). The evaluations were conducted on the day of the stress induction and after 7, 14, 21, 28, 35, 42, 49 and 56 days of the treatment. After 15 days of return to normoxic environment, plant survival was assessed. Growth (height, dry mass of shoots and roots), vigour, carbohydrate content and the activity of enzymes involved in anaerobic metabolism (lactate dehydrogenase, pyruvate decarboxylase and alcohol dehydrogenase) were also evaluated. Our results suggested that sesbania plants are tolerant to flooding, because they can survive being submerged for 56 days. The reasons for this tolerance include the accumulation and use of carbohydrates in the leaves and roots, maintenance of growth and the activation of anaerobic metabolism, particularly in steps catalysed by the enzymes pyruvate decarboxylase and alcohol dehydrogenase.

Abstract: Fil: Fernandez Honaine, Mariana. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geologia de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernacion. Comision de Investigaciones Cientificas. Instituto de Geologia de Costas y del Cuaternario; Argentina

Abstract: Light and scanning electron microscopy as well as histochemical reactions were employed to investigate the leaf structure and secretory activity of an adventive perennial pest that is rapidly dispersing in the Mediterranean region. Interesting structural characteristics, not common among the well-adapted native Mediterranean phanerophytes, were observed. Although ‘unconventional’, these structural characteristics produce an ecologically equivalent, xeromorphic leaf on a plant that proves to be competitive and very efficient under the Mediterranean climatic conditions.

Abstract: Many Caladenia species have been reduced to extremely small and/or fragmented populations, and reintroduction/translocation into natural or rehabilitated habitats, by using ex situ propagated plants or via direct seeding, represents an important adjunct in conservation planning. However, Caladenia species are some of the most difficult terrestrial orchid taxa to propagate, in part because of the specificity of the mycorrhizal associations and the need to provide growing conditions that suit both the mycorrhizal fungi and Caladenia plants. The present paper reviews recent advances in Caladenia propagation and reintroduction methods, including in vitro seed germination, transferral from in vitro to nursery environments, ex vitro symbiotic germination (germination in inoculated nursery media), nursery cultivation, the use of nurse plants and reintroduction of Caladenia into natural habitats by using seed, dormant tubers or growing plants. Techniques discussed in the present paper increase the options for future Caladenia conservation programs, especially for those species currently on the brink of extinction.

Abstract: Secretory structures are present in many vascular plants and have an important ecological role as a plant defence mechanism against herbivors and pathogens Internal secretory spaces of lipid substances are widespread in the Asteraceae However, information about the occurrence of these structures in thickened underground systems is sparse, compared with what we know about aerial systems The main objective of the present paper was to investigate the occurrence, formation and chemical nature of the secretory structures in six Asteraceae species belonging to the following tribes: Eupatorieae (Mikania cordifolia and M sessilifolia), Mutisiae (Trixis nobilis), Plucheeae (Pterocaulon alopecuroides) and Vernonieae (Vernonia elegans and V megapotamica) The samples were collected in areas of Cerrado (tropical savanna) in the state of Sao Paulo, Brazil The secretory structures found were cortical canals in roots (T nobilis, P alopecuroides, V elegans and V megapotamica), cortical cavities in roots (M cordifolia, M sessilifolia and P alopecuroides), cavities in the secondary phloem of roots (T nobilis), cortical cavities in the xylopodium (M cordifolia, M sessilifolia, P alopecuroides and V megapotamica) and in the underground stem (T nobilis), and canals in the secondary xylem in the xylopodium (M cordifolia and M sessilifolia) Histochemical tests showed the presence of lipid substances in all structures

Abstract: The foliar structure of 44 species of Myrtoideae Nied. (Myrtaceae) was described to characterise the anatomy of the leaves in this subfamily and also to recognise particular features in each genus and/or subtribe. In the present study, nine genera of the subtribe Myrtinae, five genera of the subtribe Myrciinae and eight genera of the subtribe Eugeniinae were examined. All of them have dorsiventral and hypostomatic leaves, with stomata slightly protruded in relation to other epidermal cells; the leaves also present secretory cavities, idioblasts containing druses and vascular bundles with phloem on both adaxial and abaxial sides. Some surface features have diagnostic value for all genera of these three subtribes, such as the percentage of palisade parenchyma, the presence or absence of an adaxial hypodermis, the occurrence of an extension to the vascular bundle sheath, and the shape and position of the vascular system of the midrib. These features are described for each of the species studied and the results are discussed in a taxonomical context.

Abstract: Macadamia integrifolia Maiden & Betche (Proteaceae) from eastern Australia is farmed for its edible nuts and is capable of accumulating high foliar concentrations of manganese (Mn). It was investigated here in a pot trial, where a range of physiological responses to Mn treatment were measured. Although Mn uptake was initially slow, final foliar concentrations increased linearly with treatment levels. The highest observed mean foliar concentration of Mn was 7900 μg g–1 dry weight (dwt). No negative effect of Mn accumulation on plant growth was apparent, even at the highest treatment concentration. Two groups of plants, each exposed to either full sunlight or part shade were identically treated with Mn. At the highest treatment concentration of Mn, the mean foliar concentrations of Mn of the former group were found to be significantly higher than those of the latter. Because M. integrifolia is cyanogenic, leaf cyanogenic glycosides were quantified to test for a relationship between the known chemical defence strategy of cyanogenesis and a proposed one of Mn accumulation. However, further studies are required to clarify this. Quantitative organic acid analyses showed that oxalate ion may bind excess Mn in M. integrifolia leaves. That Mn is not accumulated in M. integrifolia fruit could render the species potentially useful for remediating Mn-affected soils long-term, while serving as a food crop.

Abstract: Caladenia contains 376 species and subspecies, of which almost all are endemic to temperate and southern semiarid Australia. Eleven species occur in New Zealand, 10 of which are endemic, and one species is widely distributed in eastern Australia and the western Pacific. Only three species occur in both south-western and south-eastern Australia. At subgeneric level, Drakonorchis is endemic to the South-west Australian Floristic Region (SWAFR), Stegostyla to eastern Australia and New Zealand, whereas three subgenera, Calonema, Phlebochilus and Elevatae occur on both sides of the Nullarbor Plain. Subgenus Caladenia is primarily eastern Australian but also extends to the western Pacific. The largest subgenera (Calonema and Phlebochilus) have radiated extensively, with Calonema exhibiting a greater concentration of species in more mesic parts of the SWAFR than Phlebochilus. Within the SWAFR, the major biogeographic division within Caladenia follows the 600-mm isohyet. Within rainfall zones, biogeographic districts for Caladenia correlate with a combination of underlying geology and surface soils. Areas of high endemism contain diverse edaphic environments. Climatic and edaphic requirements are likely to be key drivers of rarity in Caladenia, although these parameters may be acting in concert with mycorrhizal and pollinator specificity.

Abstract: As part of the Global Observation Research Initiative in Alpine Environments program, the relative contribution of abiotic variables in explaining alpine vegetation was determined for five summits on a spur of Mount Clarke in the Snowy Mountains, Australia. The composition of vascular plant species and life-forms, and topography were determined, and soil nutrients and soil temperature were measured on each aspect of each summit by standardised methods. Ordinations were performed on the composition of vascular plant species and life-forms, topography, soil nutrients and soil temperature-derived variables. Abiotic variables were tested against the biotic dissimilarity matrices to determine which were best correlated with current plant composition. Summits differed in plant composition, with a decrease in the cover of shrubs, and an increase in herbs and graminoids with increasing altitude. Altitude was the main determinant of species composition, accounting for more than 80% of the variation among summits. Soil temperature variables accounted for more than 40% of the variation in composition among summits. Soils were not significantly different among summits, although certain soil variables, principally calcium, were important in predicting plant composition. Because temperature is correlated with current vegetation on these five summits, predicted increased temperatures and decreased snow cover are likely to affect future plant composition in this mountain region.

Abstract: Changes in the density of woody vegetation in arid and semiarid rangelands have the potential to dramatically reduce productivity as well as adversely affect ‘natural’ ecosystem processes. Many parts of Australia are believed to have experienced thickening of woody vegetation since European occupation and the associated changes to fire and grazing regimes that followed. Unfortunately there is little empirical evidence to support a widely held perception of thickening. This study analyses the available historical aerial photographic coverage for the mulga lands bioregion of south-western Queensland, Australia; a record spanning the second half of the twentieth century. Changes in woody vegetation canopy cover were assessed for 190 sites. More than half of the sites had no evidence of mechanical disturbance and thus reflected general, or background trends in woody vegetation cover. The region-wide average extent of change on these undisturbed sites was estimated to be approximately a 3.6% increase in canopy cover over the study period. Thus, a trend toward vegetation thickening was detected. However, large variation was observed depending on the land systems and rainfall zone where sites were located. The results are discussed in the context of century scale climate variability and perceptions of vegetation change and a tentative explanatory model is presented to account for the observed data.

Abstract: Studies on the pollination biology of Eriocaulaceae are scarce although particularly interesting because of its inclusion in the Poales, a predominantly wind-pollinated order. The pollination biology of Syngonanthus elegans (Bong.) Ruhland was studied during two annual flowering periods to test the hypothesis that insect pollination was its primary pollination system. A field study was carried out, including observations of the morphology and biology of the flowers, insect visits and pollinator behaviour. We also evaluated seed set, seed germination and seedling development for different pollination modes. Although seeds were produced by self-pollination, pollination by small insects contributed most effectively to the reproductive success of S. elegans, resulting in the greatest seed set, with the highest germination percentage and optimum seedling vigour. The floral resources used by flower visitors were pollen and nectar that was produced by staminate and pistillate flowers. Self-pollination played a minor role and its consequence was inbreeding depression.

Abstract: By conducting reintroductions of the endangered terrestrial orchid Diuris fragrantissima D.L.Jones & M.A.Clem. we compared planting at the following three stages of the natural perennial growth cycle: as actively growing symbiotic plants in spring and autumn and as dormant tubers in summer. Plants reintroduced in spring and autumn were incorporated into randomised treatments involving soil aeration and addition of a mycorrhizal fungus. The addition of a mycorrhizal fungus and soil aeration together significantly increased survival and flowering of plants reintroduced in spring, whereas they had no significant effect on plants reintroduced in autumn. Addition of a fungus without soil aeration did not improve plant survival or flowering. Reintroducing actively growing plants was more successful than reintroducing dormant tubers, with 32.5% and 29.1% plants (reintroduced in spring and autumn, respectively) and 11.0% of tubers persisting after 4 years. Although survival of reintroduced plants declined at a rate of 16.9% per year for 4 years following reintroduction, survival of remnant plants remained relatively constant, ranging from 80.0 to 93.0%. Tuber size was positively correlated with survival and flowering of reintroduced plants for 2 years following reintroduction. A general trend was observed towards the increased likelihood of re-emergence and flowering of plants that flowered in previous seasons.

Abstract: Australian sexually deceptive orchids are typically highly pollinator specific, each species having a single unique hymenopteran pollinator species. Pollinator specificity in six of the nine described species in the Chiloglottis gunnii Lindl. complex was investigated by using field pollinator-choice tests, with Chiloglottis taxa translocated within and among biogeographical regions. Specific pollinators revealed the existence of five undescribed cryptic taxa in the C. gunnii complex, three within C. pluricallata D.L.Jones and two within C. valida D.L.Jones, in addition to the six described species. Of the 11 Chiloglottis taxa, 10 had a single thynnine-wasp pollinator throughout their sometimes large distributions, whereas one, C. valida, had a second pollinator in parts of its distribution. Eleven pollinators belonged to the genus Neozeleboria and one to Eirone. Pollinator-choice testing showed that cross-attraction of pollinators occurs between three geographically isolated Chiloglottis taxa on the New South Wales (NSW) New England Tableland and taxa in the South Eastern Highlands of NSW and Victoria. The data suggested there is sharing of chemical attractants and supported the recognition of at least five odour types within Chiloglottis, each encompassing one to three orchid taxa and their pollinators. The following two broad generalisations are made: (1) there is no cross-attraction of pollinators among sympatric Chiloglottis species, i.e. sympatric orchid taxa do not share attractant odours; and (2) all Chiloglottis species have different specific pollinators, although they may share attractant odours allopatrically. Some 28 thynnine-wasp species were attracted as minor non-pollinating responders to Chiloglottis taxa; five of these were pollinators of other Chiloglottis species. These wasps were much more taxonomically diverse than the pollinators, belonging to six genera, and suggest that some orchid-odour components are widely shared within the sex pheromones of the Thynninae.

Abstract: Extrafloral nectaries (EFNs) are commonly found in Passiflora L. Reports have been made on the occurrence of resin-producing structures morphologically similar to EFNs in the genus. The objective of this study was to characterise the morphoanatomy and development of leaf secretory structures in Passiflora amethystina and to use chemical and histochemical tests to detect the presence of sugars in the exudates. Samples of leaf blade and petioles in different developmental stages were collected and subjected to usual techniques using light and scanning electron microscopy. Secretion samples were analysed by high performance liquid chromatography. The concentration of total sugars in the secretion amounted to 39.67% for blade EFNs and 52.82% for petiolar EFNs. EFNs consist of a secretory, uni- or bistratified palisade epidermis, arising from the protoderm by means of anticlinal and periclinal divisions, glandular parenchyma originated from the ground meristem, and xylem and phloem elements formed from the procambium. Exudate accumulated in a subcuticular space formed outside the epidermal cells from where it was then released. Histochemical tests showed a positive reaction for neutral polysaccharides. The results confirm that the leaf secretory structures are indeed extrafloral nectaries, and these findings constitute important information for studies on the taxonomy and ecology of this species.

Abstract: Caladenia orientalis (G.W.Carr) Hopper & A.P.Br. is a critically endangered orchid. The largest known populations are confined to fire-managed coastal heathland in southern Victoria. Trends in population dynamics at two closely occurring sites were evaluated against time since fire and rainfall, between 2000 and 2008, to provide ecological and biological information relevant to population management. At both sites, decreased plant size was inversely correlated with time since fire and the number of non-reproductive plants was positively correlated with time since fire. Rates of flowering were inversely correlated with time since fire at only one site (Population 2). The vegetation at this site rapidly accumulated after fire, whereas recovery was relatively slow at the other site. Rainfall was not correlated with rates of flowering or leaf width at either of the study sites, although there was a weak inverse relationship between rainfall and the number of non-reproductive plants at one site (Population 1). Rates of pollen transport and fruit set were within reported ranges for deceptive species. Fruiting plants were significantly smaller in the following year, whereas non-reproductive plants remained the same size. The results suggest that there may be costs associated with reproductive effort, and that hand-pollinating plants to boost seed production may lead to decreased plant size in the following year. Annual variation in rates of flowering may be influenced by previous reproductive effort. However, long-term population trends are better explained by competition from dominant shrubs, which become increasingly abundant with a lack of fire. Future management prescriptions should include site-specific fire regimes to maintain an open heathland.

Abstract: Our knowledge of the composition of the waxes on the surfaces of Eucalyptus leaves is growing but that of plant primary metabolites has been completely overlooked. The diffusion of primary metabolites above the cuticle exposes them to a variety of herbivorous taxa and has the potential to influence their responses to that plant. Juvenile leaves of two families of Eucalyptus globulus Labill. ssp. globulus and two families of E. nitens (Deane & Maiden) Maiden had 11 out of 16 of the epicuticular waxes that were detected in common. However, two phenylethyl esters (waxes) were only detected on leaves of one family of E. globulus and two benzyl esters (waxes) were not detected or were uncommon in samples from E. nitens. Wax compounds were generally found in samples from both leaf surfaces but a few were only detected in samples from particular sides. Species and families of eucalypt did not differ significantly in the concentrations of free sugars, polyols, malic acid or γ-aminobutyric acid (GABA) (all plant primary metabolites) collected from the surfaces of leaves. However, concentrations of all these metabolites were usually higher in collections from the upper surfaces of leaves. High wax abundance, especially on the lower surfaces of E. globulus leaves, is suspected to have hindered dissolution of all the primary metabolites quantified. Several free amino acids exhibited significant species-level differences in concentrations, namely the aromatic, amide and sulfur-containing amino acids as well as proline; family-level differences in amino acid concentrations were not significant. Australian and overseas evidence showing that differences in waxes and primary metabolites can be influential in plant susceptibility to herbivorous taxa is considered with respect to the threats posed by the autumn gum moth and Mycosphaerella leaf spot fungi.

Abstract: Gochnatia polymorpha (Less.) Cabrera is a widespread tree species found in different physiognomies of neotropical savanna (cerrado) formations of south-eastern Brazil. The present study describes some leaf anatomical characteristics of this species as a function of the time of leaf flush, during dry or wet seasons. This species presents anatomical plasticity in the cuticle, palisade parenchyma and abaxial epidermis as well as in stomatal size and stomatal and trichome density, which are leaf structures linked with water-status control. Leaf structure changed to suit the particular environmental conditions during dry and wet seasons. The production of different wet- and dry-season leaf types in G. polymorpha could be a response to drought and an adaptation to environmental constraints in the cerrado.

Abstract: Many widely known invasive plants are well integrated into native plant-pollinator networks. Typically, these invadershaveentomophilous flowerswhicharevisitedbyadiversearrayofpollinators.Thetypeofbreedingsystemandthe role that pollination services play in the reproductive success of invasive plants have, however, received little attention. We studied the breeding system and pollen limitation of two entomophilous invasive plants, Carpobrotus affine acinaciformis and Opuntia stricta, in different Mediterranean coastal localities in north-eastern Spain. Both species are, to some degree self-compatible; however, because of frequent visitation, open pollination increased the seed set in both speciesbyatleast50%.WhereasO.strictashowednopollenlimitation,somepopulationsofC.aff.acinaciformishadalower seed set in open-pollinated flowers than in flowers where supplementary hand-pollination ensured out-crossing. This local pollenlimitationinC.aff.acinaciformiscouldbeduetothelowefficiencyofitsvisitors(mainlybeetles)oritshybridstatus. OnthebasisofpreviousstudiesonCarpobrotussp.hybridcomplexes,wesuggestthatthevariabilityamongsitesintheseed set of open-pollinated flowers is caused by different degrees of hybrid introgression. Not withstanding, we found the C. aff. acinaciformis seed sets studied were higher than those reported in other regions. Further research is needed to assess the invasion potential of these hybrids in Mediterranean shrublands.

Abstract: Cat’s claw creeper, Macfadyena unguis-cati (L.) Gentry (Bignoniaceae) is a major environmental weed of riparian areas, rainforest communities and remnant natural vegetation in coastal Queensland and New South Wales, Australia. In densely infested areas, it smothers standing vegetation, including large trees, and causes canopy collapse. Quantitative data on the ecology of this invasive vine are generally lacking. The present study examines the underground tuber traits of M. unguis-cati and explores their links with aboveground parameters at five infested sites spanning both riparian and inland vegetation. Tubers were abundant in terms of density (~1000 per m2), although small in size and low in level of interconnectivity. M. unguis-cati also exhibits multiple stems per plant. Of all traits screened, the link between stand (stem density) and tuber density was the most significant and yielded a promising bivariate relationship for the purposes of estimation, prediction and management of what lies beneath the soil surface of a given M. unguis-cati infestation site. The study also suggests that new recruitment is primarily from seeds, not from vegetative propagation as previously thought. The results highlight the need for future biological-control efforts to focus on introducing specialist seed- and pod-feeding insects to reduce seed-output.

Abstract: There have been numerous attempts to transfer Papaya ringspot virus type P (PRSV-P) resistance from wild Vasconcellea relatives to Carica papaya L. Success has been limited by the high degree of genetic divergence and thus incompatibility between Vasconcellea spp. and C. papaya. In the present work, intergeneric hybrid populations of C. papaya × V. pubescens Lenne et Koch, C. papaya × V. parviflora A. DC. and interspecific populations of V. pubescens × V. parviflora were produced and evaluated for morphological characteristics and PRSV-P resistance. F2 and F3 populations were produced from the V. pubescens × V. parviflora F1 and PRSV-P resistant individuals with homozygous genotypes (RR) were selected with the aid of a co-dominant CAPS marker and backcrossed to V. parviflora or outcrossed to C. papaya. Leaf vein number (seven) from V. pubescens, flower colour (pink) from V. parviflora and petiole colour (red–green) and plant size from C. papaya were transferred as dominant traits in interspecific and intergeneric crosses. Other traits, e.g. flower shape and fruit size, were intermediate in hybrids. When the wild species or their hybrids were outcrossed to C. papaya, inheritance patterns did not always follow Mendelian ratios, suggesting abnormal pairing of chromosomes or preferential elimination of the Vasconcellea genes. For example, in crosses between C. papaya × V. pubescens, all flowers were female and in crosses between C. papaya × V. parviflora, the cream flower colour of C. papaya was dominant over the pink colour of V. parviflora. However, the PRSV-P resistance gene from V. pubescens was successfully backcrossed into V. parviflora from F2 hybrids, and in the F1 hybrids between C. papaya and V. parviflora, 45% pollen fertility was obtained thus V. parviflora is proposed as a potential bridging species between C. papaya and V. pubescens.

Abstract: Clonality and hybrid origin influence the conservation status of rare and restricted species. Eucalyptus bennettiae Carr & Carr is a rare species known only from a few individuals that may be clonal and may have arisen through hybridisation between other co-occurring species. The hybrid status and clonality of E. bennettiae was investigated with analysis of microsatellite variation in E. bennettiae compared with its putative parents, E. lehmannii subsp. parallela, E. sporadica and E. astringens subsp. redacta, identified through morphological characteristics. Analysis of microsatellite variation revealed clonality with one individual present at each location, and additivity of alleles and no unique alleles in E. bennettiae compared with two of the putative parents, E. lehmannii subsp. parallela and E. sporadica. In addition, E. bennettiae displayed intermediacy in species relationships and measures of relatedness, and assignment tests showed mixed ancestry in relation to these species but not the third putative parent, E. astringens subsp. redacta. These findings confirm that E. bennettiae is a hybrid and evaluation of the taxon for conservation protection shows that it does not satisfy the criteria for listing as a threatened species.

Abstract: The application of molecular techniques for defining evolutionary units in Caladenia has largely focussed on addressing relationships at the subgeneric and deeper levels. However, in light of the morphological complexity present in this diverse genus, molecular markers offer additional characters for the refinement of taxonomy at the species level. In the present study, we explored the utility of marker systems with demonstrated application for defining fine-scale units, both in terms of phylogenetic information and in the context of DNA barcoding. We also provide a working example of the use of molecular techniques for identifying the source plants of pollinia collected from passively sampled pollinators and for identifying sterile plants.

Abstract: Insect visitors to the flowers of Eucalyptus regnans FMuell in a remnant natural stand were classified into 33 functional pollinator groups according to taxonomic affinity and body size In total, 92% of insects caught were dipterans; however, most of these were small and did not contribute significantly to pollination For the majority of taxa, which have short mouthparts and therefore need to intrude themselves into the flower while feeding on nectar, there was a highly significant relationship between body length and the number of E regnans pollen grains carried on the body Mean pollen loads ranged from 20 grains per insect for sepsid flies to 84 000 for large tachinid flies An index of pollen-deposition potential, which is based on population size and pollen load, suggested that the larger tachinid, calliphorid and syrphid flies were the most important pollen vectors and that larger sphecid wasps also played a significant role Many taxa appeared to contribute little to pollination because they were uncommon and/or did not carry large quantities of pollen A convention is proposed whereby groups are weighted according to their contribution to total pollen-deposition potential For E regnans, a ratio of 5 Diptera/1 Hymenoptera + (Coleoptera/Lepidoptera) is described, with the taxa in parentheses contributing less than 10% of the total

Abstract: Nivicolous myxomycetes were collected from alpine areas of south-eastern Australia during the period of middle to late October 2004. Most collections came from the high-elevation area around Mount Kosciuszko, the highest peak on the continent at 2228 m, in the Snowy Mountains of New South Wales, and additional collections were obtained from two areas, Mount Buller and Mount Hotham, in the Victorian Alps of northern Victoria. Approximately 300 collections were obtained during a period of 2 weeks, including species such as Diderma alpinum, Didymium dubium, Lamproderma ovoideum, Physarum albescens and P. alpinum, not previously known to occur in mainland Australia. Lamproderma maculatum and L. zonatum were collected for the first time in the southern hemisphere, and another species of Lamproderma was described as new to science in a previous paper. In contrast to most other areas of the world where nivicolous myxomycetes have been studied, species of Diderma have been represented poorly among the collections from Australia.

Abstract: Calytrix breviseta Lindl. subsp. breviseta is a critically endangered, obligate-seeder shrub within fire-prone kwongan of south-west Western Australia. Little is known about the species’ reproductive biology and how threatening processes, particularly altered fire regimes and exotic species invasion, will impact the long-term viability of the species. This study aims to elucidate the species’ reproductive biology and patterns of seedling recruitment during succession after fire. The effects of changes to the fire return interval and exotic species invasion on the long-term viability of the species is also described. The species exhibits abundant recruitment following fire and the application of a smoke treatment significantly improves germination, similar to many other Western Australian shrubs. However, significant inter-fire recruitment was observed up to 10 years following fire, leading to the presence of multi-aged subpopulations, although seedling recruitment was negligible >20 years after fire. The juvenile period is short at 3–4 years to first flowering. Population viability analysis (PVA) predicted that the optimal fire return interval to maintain C. breviseta subsp. breviseta was dependent on the carrying capacity (K) of the community and the number of individuals present. Carrying capacity will be related to site quality and competition from invasive species. PVA showed that if K remains high, then the optimal fire return interval is ~15–20 years, but under lower carrying capacity, (i.e. weed competition) fires decrease the likelihood of population survival.

Abstract: Species of the pantropical genus Erythrina (Fabaceae) are visited by perching and/or hovering birds in the mainland. At the oceanic island of Fernando de Noronha, north-eastern Brazil, we found that Erythrina velutina Willd. blooms during the dry season and the flowers are visited by a small vertebrate assemblage. Flowers last 2 days and their stigmas remain receptive, although only first-day flowers produce nectar. Nectar is dilute and produced copiously. All terrestrial native vertebrates (three of them endemics), the dove Zenaida auriculata noronha, the perching birds Vireo gracilirostris and Elaenia ridleyana, and the lizard Euprepis atlanticus are regular visitors and pollinators. The features of E. velutina conform to those of passerine-pollinated species within the genus. Its nectar is a resource sought by the vertebrates, which visit the inflorescences from dawn to sunset. Since none of the visitors depends on nectar as a major food source, the flowers are likely to serve a dual purpose, i.e. water balance and energy intake, similarly to the findings for some Erythrina species in Neotropic and Palaeotropic mainlands. However, E. velutina is the only species within the genus that is visited and pollinated by doves and lizards.

Abstract: We examined the responses of two tree fern species (Dicksonia antarctica and Cyathea australis) growing under shade or variable light (intermittent shade) to sudden exposure to high light levels. Steady-state gas exchange as well as dynamic responses of plants to artificial sunflecks indicated that difference in growth light environment had very little effect on the tree ferns’ capacities to utilise and acclimate to prevailing light conditions. Two weeks of exposure to high light levels (short-term acclimation) led to decreases in all photosynthetic parameters and more negative predawn frond water potentials, mostly irrespective of previous growth light environments. After 3months in high light levels (long-term acclimation), D. antarctica fully recovered, while C. australis previously grown under variable light, recovered only partially, suggesting high light level stress effects under the variable light environments for this species.

Abstract: Climate warming has the potential to directly affect plant growth rates by accelerating plant processes, and through intermediate affects associated with increased length of the growing season and changes to soil processes. Alpine and subalpine ecosystems may be particularly vulnerable to climate warming because species are adapted to a cold environment and have limited upslope refugia in Australia. In the present study, the vegetative growth of seven subalpine open-heath species was examined in response to 3 years of warming and a wildfire. The warming experiment was established in late 2003 on the Bogong High Plains, Australia, using the protocols of the International Tundra Experiment (ITEX). During the growing seasons (snow-free periods) in 2004/2005 and 2005/2006 leaves and stems were monitored on common or widespread species from each of the major vascular plant growth forms. Plants were monitored inside and outside passively warmed open-topped chambers, at sites that were burnt in early 2003 and sites that escaped fire. In the short-term, warming had significant positive relationships with relative growth rates of three species, including Celmisia pugioniformis (forb; P=0.09), Carex breviculmis (graminoid; P=0.004) and Asterolasia trymalioides (shrub; P=0.02). Burning had significant positive effects (P<0.05) on the relative growth rates of two of these species, C. pugioniformis and C. breviculmis, as well as for Plantago euryphylla, Poa hiemata and Pimelea alpina. For P. euryphylla and P. alpina, the interaction of warming and burning showed significant relationships with relative growth rates, a negative relationship in P. euryphylla (P=0.03) and a positive relationship in P. alpina (P=0.07). Year and season were also found to affect the relative growth rates of most species (P<0.05). These findings agree with previous northern hemisphere ITEX and other warming experiment results; that is, warming has a positive effect on species' growth responses. In the present study, it is likely that continued climate warming may result in positive growth responses in other subalpine species across growth forms. Our findings emphasise the value of examining multiple species in climate-change studies.