Tropical wetlands and REDD+: Three unique scientific challenges for policy

The carbon sequestration and storage value of terrestrial habitats is now increasingly appreciated, and is the basis for Payment for Ecosystem Service (PES) policies such as REDD+. Tropical wetlands may be suitable for inclusion in such schemes because of the disproportionately large volume of carbon they are able to store. However, tropical wetlands offer a number of unique challenges for carbon management and policy compared to terrestrial forest systems: 1) Tropical wetlands are dynamic and subject to a wide range of physical and ecological processes that affect their long-term carbon storage potential – thus, such systems can quickly become a carbon source instead of a sink; 2) Carbon dynamics in tropical wetlands often operate over longer time-scales than are currently covered by REDD+ payments; and 3) Much of the carbon in a tropical wetland is stored in the soil, so monitoring, reporting and verification (MRV) needs to adequately encapsulate the entire ecosystem and not just the vegetative component. This paper discusses these physical and biological concepts, and highlights key legal, management and policy questions that must be considered when constructing a policy framework to conserve these crucial ecosystems.

Diet of the Mountain Pygmy-possum, Burramys parvus (Marsupialia: Burramyidae) and other small mamma ls in the alpine environment at Mt Higginbotham, Victoria.

The diets of Burramys parvus, Rattus fuscipes and Antechinus swainsonii in Podocarpus lawrencei heathland in alpine Victoria during the non-winter period were determined from analysis of 264 faecal pellets. Both frequency of occurrence and mean percentage composition of dietary items in the samples were determined; the Iatter being used to assess the diet. We found B. parvus to be an omnivore concentrating on insec ts. It eats a variety of foods but the Bogong Moth (Agrolis infusa) is heavily exploited (31 % of the composition of faecal samples) especially by females during the breeding season (46 %). Other components of the diet are other invertebrates, predominantly insects (32 %) and vegetative material (16 %). Seasonal differences in the composition of the diet of B. parvus were due to the exploitation of fruit in the non-breeding season. No differences in diet were observed between age-classes and the sexes but females are sedentary in food resource-rich habitats, whilst when not breeding, males occur in areas of poorer food resources. Circumstantial evidence suggests that during facultative hibernation a major dietary component of B. parvus may be seeds, cached from the previous summer-autumn. The diet of R. fuscipes consists mainly of insects (12 %) and the largest vegetative component was seeds (10.1 %). Fungi were found in 53 % of faecal samples of R. fuscipes but could not be quantified as a percentage composition of diet. The species is classified as a selective omnivore. The diet of A. swainsonii consisted of 68 % in sec ts, 10.4 % of insect setae and worms with the major vegetative component (5.2 %) being soft fruits. Burramys parvus, relative to the other small mammals with which it cohabits, has become a specialist in exploiting the abundant and rich food resource of Bogong moths.

RESPONSE OF DIFFERENT GROWTH FORMS OF POA ANNUA L. (ANNUAL BLUEGRASS) TO HERBICIDES APPLIED BEFORE OR AFTER EMERGENCE

The response of erect/annual and prostrate/perennial strains of Poa annua to herbicides was examined by treating soil with bensulide or chlorthal-dimethyl prior to emergence and by treating immature and mature plants with endothal or linuron. Chlorthal-dimethyl gave better control than bensulide as measured by a greater reduction in the number of seedlings surviving and dry weight of the survivors. Linuron was more effective than endothal in reducing biomass production of both immature and mature plants. Differential response of the erect and prostrate growth forms was not apparent for either bensulide or chlorthal-dimethyl, or for total biomass production of immature and mature plants in response to endothal or linuron. However, a significant growth form by treatment interaction was obtained for the vegetative component of mature plants, with the prostrate plants showing a greater weight reduction than erect individuals relative to the control. The weight of the reproductive component was equally reduced in both growth forms. Percent dry weight allocated to reproductive growth, which was 35 and 15% for the erect and prostrate growth form, respectively, remained relatively constant for both growth forms for all herbicide treatments.

Biomass and nutrient distribution patterns in a young Pseudotsugamenziesii ecosystem

Calculations are presented giving biomass and quantities of nitrogen, phosphorus, potassium, calcium, and magnesium contained in soil, understory vegetation, and standing arboreal components of a low-site, immature Pseudotsugamenziesii (Mirb.) Franco ecosystem on southern Vancouver Island. For the standing arboreal crop, biomass and elemental content of the foliage, live and dead branches, wood, bark, and total tree were estimated, using the formula logeY = a + b logeD2H, where D = diameter breast height and H = total tree height.The soil component contained over 70% each of the total organic matter biomass and nitrogen, calcium, and magnesium content in the ecosystem. Although the soil also contained large quantities of potassium and phosphorus, the vegetative component significantly increased in importance with regard to these two elements. Biomass and nutrient distribution patterns within the standing arboreal crop are discussed in terms of elemental concentrations and distribution between components over the diameter range encountered. The distribution of biomass and the total elemental content among the various ecosystem components are discussed and comparisons are made with related studies.