Decomposition Analysis of Waste Generation From Stocks in a Dynamic System

We conducted a decomposition analysis of material flows in a dynamic system, focusing on factors in the generation of waste consumer durables. A methodology for the analysis of consumer durables was developed and applied to three common consumer durables: cathode ray tube TVs, refrigerators, and passenger cars. The methodology decomposed changes in the numbers of waste products into three factors: changes in lifespan distribution, past trends in replacement sales, and past trends in sales for additional purchases. The decomposed equation clearly showed that the number of waste products would not necessarily be reduced by lifespan extension alone. This is because the number of waste products generated is affected not only by current lifespan distribution but also by past trends in sales for replacement and in additional purchases. The results show that changes in past replacement sales influence the current generation of waste, even if current replacement sales are declining. To reduce the generation of waste products on a short‐term basis, lifespan must be extended until the waste‐reducing effect of lifespan extension exceeds the waste‐increasing effect of the other two factors. From a long‐term perspective, controlling current replacement and additional purchases can be used to prevent future waste product generation.     

Feeding ecology and seed dispersal of sympatric cheirogaleid lemurs (Microcebus murinus, Cheirogaleus medius, Cheirogaleus major) in the littoral rainforest of south-east Madagascar

The lemurs of Madagascar are known for their extraordinary species diversity. The mechanisms that allow the coexistence of these species are still poorly known. Here feeding patterns were investigated for three small nocturnal lemur species of Cheirogaleidae ( Microcebus murinus , Cheirogaleus medius and Cheirogaleus major ) occurring sympatrically in a littoral rainforest in south-east Madagascar. During three rainy seasons, the plant species eaten by these three lemurs were described in relation to morphological and biochemical characteristics. All three species were mainly frugivorous and fed on 68 different plant species with small- and medium-sized fruits. A total of 91% of these forage plant species was visited by all three lemur species. Fruits larger than 25–30 mm were avoided. Seeds of a total of 51 food plant species were swallowed and passed the gut unharmed. Thus, even these smaller lemur species play an important role in seed dispersal. There were no differences in the morphological and biochemical characteristics of fruits eaten between the three species, but the feeding height was significantly different between the species. Thus, competition avoidance and niche separation are presumably not based on different feeding patterns of M. murinus , C. medius and C. major in the littoral rainforest, but on different habitat utilization.     

British mammals: from trinomials to evolutionary ecology

The study of mammals in Britain has progressed from studies of distribution and differentiation to the present time, when new challenges face mammal workers. We need to build upon past achievements and use both new technology and old-fashioned dedicated observation to learn why what mammal is whew.     

The effects of ecology on life history strategies and metabolic disturbances during development: an example from the African bovids

Life history theory predicts environmental factors to affect changes in life history strategies. However, owing to the interrelationships between body mass and life history variables, it is difficult to discern causal relationships, especially in large-bodied mammals and using a comparative approach. The situation is exacerbated in palaeobiologi-cal studies, where many of the variables cannot be observed directly. Specifically, mortality risk has been identified as one of the most important factors determining life history strategies, but its assessment is difficult. This hampers analyses of life history evolution. This study thus explored the possibility to extract previously untapped information from hard tissue, i.e. teeth, which may be useful for life history reconstruction. Histological sections of 25 molars of bovids, representing all subfamilies and spanning a wide range of body masses, were analysed with regard to: (i) molar crown formation times in relation to female body mass and gestation length, and (ii) metabolic disturbances from early to late forming teeth in relation to habitat type occupied, diet consumed and habitual walking style employed. It was found that molar crown formation times in bovids are highly correlated with gestation length once the effects of body mass have been removed. This differs from primates and indicates similarities in pre- and postnatal growth rates in these mammals. Closed-habitat species exhibit relatively fewer disturbances during development than open-country species, but the reverse holds for adult specimens. This accords with what is known about the ecological and behavioural adaptations of the species and is predicted by life history theory. It could thus be confirmed that teeth may provide vital information about life history variables. Exploitation of this information will allow hypotheses to be tested regarding the evolutionary changes in life history strategies of extinct species.     

Fire, fuels and restoration of ponderosa pine–Douglas fir forests in the Rocky Mountains, USA

Aim Forest restoration in ponderosa pine and mixed ponderosa pine–Douglas fir forests in the US Rocky Mountains has been highly influenced by a historical model of frequent, low‐severity surface fires developed for the ponderosa pine forests of the Southwestern USA. A restoration model, based on this low‐severity fire model, focuses on thinning and prescribed burning to restore historical forest structure. However, in the US Rocky Mountains, research on fire history and forest structure, and early historical reports, suggest the low‐severity model may only apply in limited geographical areas. The aim of this article is to elaborate a new variable‐severity fire model and evaluate the applicability of this model, along with the low‐severity model, for the ponderosa pine–Douglas fir forests of the Rocky Mountains. Location Rocky Mountains, USA. Methods The geographical applicability of the two fire models is evaluated using historical records, fire histories and forest age‐structure analyses. Results Historical sources and tree‐ring reconstructions document that, near or before ad 1900, the low‐severity model may apply in dry, low‐elevation settings, but that fires naturally varied in severity in most of these forests. Low‐severity fires were common, but high‐severity fires also burned thousands of hectares. Tree regeneration increased after these high‐severity fires, and often attained densities much greater than those reconstructed for Southwestern ponderosa pine forests. Main conclusions Exclusion of fire has not clearly and uniformly increased fuels or shifted the fire type from low‐ to high‐severity fires. However, logging and livestock grazing have increased tree densities and risk of high‐severity fires in some areas. Restoration is likely to be most effective which seeks to (1) restore variability of fire, (2) reverse changes brought about by livestock grazing and logging, and (3) modify these land uses so that degradation is not repeated.     

Occurrence and seasonal dynamics of Pseudodactylogyrus anguillae (Yin & Sproston) (Monogenea) in eel, Anguilla anguilla (L.), in England

Established populations of Pseudodacrylogyrus anguillae are reported from eels in England for the first time. Prevalence and abundance peak in late summer in all three localities and the parasite overwinters at low levels on eels.