Assessing the vulnerability of an assemblage of subtropical rainforest vertebrate species to climate change in south‐east Queensland

Global climate change is a threat to ecosystems that are rich in biodiversity and endemism, such as the World Heritage‐listed subtropical rainforests of central eastern Australia. Possible effects of climate change on the biota of tropical rainforests have been studied, but subtropical rainforests have received less attention. We analysed published data for an assemblage of 38 subtropical rainforest vertebrate species in four taxonomic groups to evaluate their relative vulnerability to climate change. Focusing on endemic and/or threatened species, we considered two aspects of vulnerability: (i) resistance, defined by indicators of rarity (geographical range, habitat specificity and local abundance); and (ii) resilience, defined by indicators of a species potential to recover (reproductive output, dispersal potential and climatic niche). Our analysis indicated that frogs are most vulnerable to climate change, followed by reptiles, birds, then mammals. Many species in our assemblage are regionally endemic montane rainforest specialists with high vulnerability. Monitoring of taxa in regenerating rainforest showed that many species with high resilience traits also persisted in disturbed habitat, suggesting that they have capacity to recolonize habitats after disturbance, that is climate change‐induced events. These results will allow us to prioritize adaptation strategies for species most at risk. We conclude that to safeguard the most vulnerable amphibian, reptile and bird species against climate change, climatically stable habitats (cool refugia) that are currently without protection status need to be identified, restored and incorporated in the current reserve system. Our study provides evidence that montane subtropical rainforest deserves highest protection status as habitat for vulnerable taxa.     

Abiotic and biotic factors influencing nest-site selection by Halictus rubicundus, a ground-nesting halictine bee

1. The nest-site selection behaviour of the bee Halictus rubicundus (Christ) was examined both within and across sites in the U.K. Females utilized a range of edaphic and microclimatic conditions when choosing a site to excavate a nest. Factors with broad tolerances included slope and hardness; those with much narrower limits included aspect, soil humidity and soil particle composition.
2. There was a preference for softer soils that were easier to dig within a site with a low overall density, but in much denser aggregations problems of maintaining the structural integrity of a nest led to the utilization of harder soils.
3. The thermal advantages of having a warm nest meant that the most suitable areas were those with a southern aspect and a slope that maximized the absorption of solar radiation.
4. Limited areas of substrate with the most desirable characteristics resulted in gregarious nesting ('limited substrate hypothesis').
5. Natal nest-site fidelity complemented the 'limited substrate' hypothesis in producing an aggregation of nests.     

An Investigation of Errors in Direct Counts of Aquatic Bacteria by Epifluorescence Microscopy, with Reference to a New Method for Dyeing Membrane Filters

A number of methods for observing freshwater bacteria by epifluorescence (incident light fluorescence) microscopy are examined. The suitability of each method for quantitative studies using black membrane filters is assessed. In spite of inadequacies it was considered that the use of acridine-based fluorochromes provided the best available estimate of the bacterial population. The errors which may arise when these stains are used were examined and it was noted that small changes in methodology could cause significant differences in the results obtained. The largest errors were associated with changes in volume of sample filtered and the pore size of the membrane used. A procedure for sample treatment is suggested and a new method for dyeing membrane filters is given which allows the use of 0·22-μm pore size membranes of the cellulose ester and polycarbonate type.     

Adaptation and acclimation of higher plants at the enzyme level: Speed of acclimation for apparent energy of activation of NAD malate dehydrogenase in Lathyrus Japonicus Willd. (Leguminosae)

Abstract The speed of acclimatory changes in apparent energy of activation (E_a) of NAD malate dehydrogenase was analysed in four clones of Lathyms japonicus Willd. collected over a 16° latitudinal gradient in eastern North America. Plants were grown initially for six months at either 7° night/15° day or 22° night/30° days. Following reciprocal switches in these two contrasting thermo-periods, energy of activation was relatively stable for 12 h, then oscillated until 48 h, and stabilized in about 72 h. The results suggest that the acclimation response in E_a is not due to near-instantaneous conformational changes in isozymes, but is directed primarily by temperature-mediated structural and/or functional modifications during de novo synthesis of the forms of the enzymes.     

Life span and ovarian dynamics of the pine beauty moth, Panolis flammea (D&S): the effect of low temperatures after adult emergence on reproductive success

Abstract Adult female Panolis flammea were kept at 2^oC either immediately after emergence from the pupae or immediately after mating, for periods ranging from 5 to 20 days and then placed at 15^oC together with a male moth, food supply and suitable oviposition site ( Pinus contorta foliage). Weight loss over the storage period was directly proportional to the time spent at 2^oC irrespective of whether the moths were virgin or mated. Pre-oviposition period decreased significantly from the control after more than 5 days at 2^oC, but there was no significant difference between late mated and early mated moths. The post-storage life span of late mated and early mated moths decreased in proportion to the time spent at 2^oC but late mated moths had significantly longer life spans than early mated moths. Moths mated prior to storage were significantly less fecund than moths mated after storage except those moths kept at 2^oC for 20 days where the fecundities of both treatments were identical (c. 45 eggs/female). These results are discussed in relation to the conditions likely to be experienced by P.flammea in the field and their bearing on the population dynamics of this insect.     

X-Ray Characterization of Melanins—I

The intrinsic local structure characterization of natural sepia melanin and L-dopa and tyrosine synthetic melanin powder has been carried out by X-ray diffraction using synchrotron radiation. The derived structure factor, S(q), shows six significant diffuse peaks within the q-range from 0.3 Å^-1 to 16 Å^-1 in the reciprocal space (q= (4π sin θ)/λ, 2θ is the scattering angle). The Fourier transform of S(q), which yields the radial distribution function (RDF), gives us information in real space of a 1.42 Å distance averaged over the C-C, C-O and C-N bond lengths as well as peaks at 2.40-2.41 Å, 3.67-3.71 Å and 4.67-4.70 Å discrete neighbor distances. There is a great similarity in the scattering intensity profiles of the natural and synthetic melanins indicating that the synthetically prepared material may be essentially similar to “real” melanin in its local atomic arrangements. An evidence of a prepeak at q = 0.45 Å^-1 has been confirmed which indicates a preferred length scale of ～ 13-20 Å that corresponds to the initial particle size in colloidal melanin solutions.