Hanging in the treetops: an in situ experiment in ancient hemlock assessing outbreak defoliator performance among crown levels

1. Past studies have shown that both egg lay and larval feeding of a generalist defoliator, pale‐winged gray (Iridopsis ephyraria Walker) (Lepidoptera: Geometridae), are concentrated in the mid‐lower crown of eastern hemlock [Tsuga canadensis (L.) Carr.]. 2. Using tree‐climbing techniques, we carried out in situ bioassays in large hemlock trees (～25 m) to determine whether the observed foraging preferences are adaptive and how they reflect associated intra‐tree variations in microhabitat quality associated with temperature and foliage nutritional quality. 3. In 1 of 2 years, larval survival was significantly higher in the shaded lower versus sunlit upper crown; however, in both years, groups that fed in the sunlit upper crown branches had larger male and female moths and more female‐biased sex ratios. 4. Differences in pale‐winged gray performance among crown levels were somewhat supported by trends in foliage nutritional chemistry but not well‐correlated with variation in temperature. 5. The present study is one of only a few to carry out bioassays on large mature trees and results reinforce the idea that foraging patterns of herbivores are likely to reflect trade‐offs among several factors that vary between sunlit and shaded branches within forest canopies.     

Improving biodiversity monitoring

Effective biodiversity monitoring is critical to evaluate, learn from, and ultimately improve conservation practice. Well conceived, designed and implemented monitoring of biodiversity should: (i) deliver information on trends in key aspects of biodiversity (e.g. population changes); (ii) provide early warning of problems that might otherwise be difficult or expensive to reverse; (iii) generate quantifiable evidence of conservation successes (e.g. species recovery following management) and conservation failures; (iv) highlight ways to make management more effective; and (v) provide information on return on conservation investment. The importance of effective biodiversity monitoring is widely recognized (e.g. Australian Biodiversity Strategy). Yet, while everyone thinks biodiversity monitoring is a good idea, this has not translated into a culture of sound biodiversity monitoring, or widespread use of monitoring data. We identify four barriers to more effective biodiversity monitoring in Australia. These are: (i) many conservation programmes have poorly articulated or vague objectives against which it is difficult to measure progress contributing to design and implementation problems; (ii) the case for long‐term and sustained biodiversity monitoring is often poorly developed and/or articulated; (iii) there is often a lack of appropriate institutional support, co‐ordination, and targeted funding for biodiversity monitoring; and (iv) there is often a lack of appropriate standards to guide monitoring activities and make data available from these programmes. To deal with these issues, we suggest that policy makers, resource managers and scientists better and more explicitly articulate the objectives of biodiversity monitoring and better demonstrate the case for greater investments in biodiversitymonitoring. There is an urgent need for improved institutional support for biodiversity monitoring in Australia, for improved monitoring standards, and for improved archiving of, and access to, monitoring data. We suggest that more strategic financial, institutional and intellectual investments in monitoring will lead to more efficient use of the resources available for biodiversity conservation and ultimately better conservation outcomes.     

Carbon impacts of direct land use change in semiarid woodlands converted to biofuel plantations in India and Brazil

We present an analysis of direct land use change (dLUC) resulting from the conversion of semiarid woodlands in Brazil and India to Jatropha curcas, a perennial biofuel crop. The sites examined include prosopis woodlands, managed for woodfuel production under periodic coppicing, in southern India, and unmanaged caatinga woodlands in the Brazilian state of Minas Gerais. The jatropha plantations under consideration include pruned and unpruned stands and ranged from 2 to 4 years of age. Stocks of carbon in aboveground (AG) pools, including woody biomass, coarse debris, leaf litter, and herbaceous matter, as well as soil organic carbon (SOC) were evaluated. The jatropha plantations store 8–10 tons of carbon per hectare (t C ha^?1) in AG biomass and litter when managed with regular pruning in both India and Brazil. Unpruned trees, only examined in Brazil, store less biomass (and carbon), accumulating just 3 t C ha^?1 in AG pools. The two woodlands that were replaced with jatropha show substantial differences in carbon pools: prosopis contains ～11 t C ha^?1 in AG stocks of carbon, which was very close to the jatropha stand which replaced it. In contrast, caatinga stores ～35 t C ha^?1 in AG biomass. Moreover, no change in SOC was detected in land that was converted from Prosopis to jatropha. As a result, there is no detectable change in AG carbon stocks at the sites in South India where jatropha replaced prosopis woodlands. In contrast, large losses of AG carbon were detected in Central Brazil where jatropha replaced native caatinga woodlands. These losses represent a carbon debt that would take 10–20 years to repay.     

THE SUBSTANCE VIEW: A CRITIQUE

According to the theory of intrinsic value and moral standing called the ‘substance view,’ what makes it prima facie seriously wrong to kill adult human beings, human infants, and even human fetuses is the possession of the essential property of the basic capacity for rational moral agency – a capacity for rational moral agency in root form and thereby not remotely exercisable. In this critique, I cover three distinct reductio charges directed at the substance view's conclusion that human fetuses have the same intrinsic value and moral standing as adult human beings. After giving consideration to defenders of the substance view's replies to these charges, I then critique each of them, ultimately concluding that none is successful. Of course, in order to understand all of these things – the reductio charges, defenders of the substance view's replies to them, and my criticisms of their replies – one must have a better understanding of the substance view (in particular, its understanding of rational moral agency) as well as its defense. Accordingly, I address the substance view's understanding of rational moral agency as well as present its defense.     

An eddy covariance mesonet to measure the effect of forest age on land–atmosphere exchange

We deployed a mesonet of year‐round eddy covariance towers in boreal forest stands that last burned in ～1850, ～1930, 1964, 1981, 1989, 1998, and 2003 to understand how CO₂ exchange and evapotranspiration change during secondary succession. We used MODIS imagery to establish that the tower sites were representative of the patterns of secondary succession in the region, and Landsat images to show that the individual stands have changed over the last 22 years in ways that match the spatially derived trends. The eddy covariance towers were well matched, with similar equipment and programs, which maximized site‐to‐site precision and allowed us to operate the network in an efficient manner. The six oldest sites were fully operational for ～90% of the growing season and ～70% of the dormant season from 2001 or 2002 to 2004, with most of the missing data caused by low battery charge or bad signals from the sonic anemometers. The rates of midday growing‐season CO₂ uptake recovered to preburn levels within 4 years of fire. The seasonality of land–atmosphere exchange and growing‐season length changed markedly with stand age. The foliage in the younger stands (1989, 1998, and 2003 burns) was almost entirely deciduous, which resulted in comparatively short growing seasons that lasted ～65 days. In contrast, the older stands (1850, 1930, 1964, and 1981) were mostly evergreen, which resulted in comparatively long growing seasons that lasted ～130 days. The eddy covariance mesonet approach we describe could be used within the context of other ecological experimental designs such as controlled manipulations and gradient comparisons.     

Production and fitness of Fusarium pseudograminearum inoculum at elevated carbon dioxide in FACE

Rising atmospheric carbon dioxide (CO₂) concentration is increasingly affecting food production but how plant diseases will influence production and quality of food under rising CO₂ is not well understood. With increased plant biomass at high CO₂ the stubble‐borne fungal pathogen Fusarium pseudograminearum causing crown rot (CR) of wheat may become more severe. We have studied inoculum production by Fusarium using fungal biomass per unit wheat stubble, stem browning from CR and the saprophytic fitness of Fusarium strains isolated from two wheat varieties grown in 2007 and 2008 at ambient and elevated CO₂ in free‐air CO₂ enrichment (FACE) with or without irrigation and once in a controlled environment. Fungal biomass, determined using primers for fungal ribosomal 18s and the TRI5 gene, increased significantly at elevated CO₂ in two of the three studies. Stem browning increased significantly at elevated CO₂ in the 2007 FACE study. At elevated CO₂ increased stem browning was not influenced by irrigation in a susceptible variety but in a resistant variety stem browning increased by 68% without irrigation. Wheat variety was significant in regression models explaining stem browning and Fusarium biomass but pathogen biomass at the two CO₂ levels was not significantly linked to stem browning. Fusarium isolates from ambient and elevated CO₂ did not differ significantly in their saprophytic fitness measured by the rate of colonization of wheat straw. We show that under elevated CO₂Fusarium inoculum in stubbles will be amplified from increased crop and pathogen biomass while unimpeded saprophytic fitness will retain its effectiveness. If resistant varieties cannot completely stop infection, Fusarium will rapidly colonize stubble to further increase inoculum once the crop is harvested. Research should move beyond documenting the influence of elevated CO₂ to developing disease management strategies from improved knowledge of pathogen biology and host resistance under rising CO₂.     

The involvement of aquaglyceroporins in transport of boron in barley roots

Boron (B) enters cells as the uncharged boric acid, a small neutral molecule with sufficient lipid solubility to cross cell membranes without the aid of transport proteins. The extent to which the observed uptake rates for B in plants can be explained by this simple physical process was examined by applying treatments expected to inhibit the membrane transporters most likely to be involved in B transport. These experiments established that at least 50% of B uptake could be facilitated by transporters. The B transport characteristics of two barley aquaglyceroporins, HvPIP1;3 and HvPIP1;4, were investigated using yeast complementation assays. Expression of both genes in yeast resulted in increased B sensitivity. Transport assays in yeast confirmed that HvPIP1;3 and HvPIP1;4 are both capable of transporting B. The physiological role of these HvPIP1 genes in B transport is uncertain since their expression was not responsive to B nutritional status, and they continued to be expressed under toxicity conditions.     

Characterization of 26 new microsatellite loci in the dugong (Dugong dugon)

Twenty‐six microsatellite loci have been isolated from a dugong (Dugong dugon). The average heterozygosity was 0.52 with two to 10 alleles per locus surveyed from 50 individuals. The markers are suitable for genetic mark–recapture (P_ID = 5 × 10^?16) in dugongs and they could also be used to quantify physical tag loss, estimate relatedness, assign paternity, elucidate population structure and identify migrants. The loci also amplified in Florida manatees (22/26) and Asian elephants (6/26).