Old endemics and new invaders: alternative strategies of passerines for living in the Australian environment

Life history parameters of ”old endemics” and ”new invaders” among the Australian passerines were compared, controlling for phylogeny by using current, phylogenetic research methods. Old endemics were found to have significantly smaller clutches and demonstrated significantly more cooperative breeding than the new invaders, whose fledging periods are significantly longer than those of the old endemics. We argue that breeding under conditions of a small annual food increment during the breeding season, as is probably the situtation in Australia, is possible only when clutch size is small, or while breeding cooperatively, or by extending the fledging period. Our data show that the old endemics use the first two options, while the new invaders employ the third. Received: 10 February 1999 / Received in revised form: 10 November 1999 / Accepted: 20 November 1999     

Changes in gonadal development,androgenic gland cell structure,and hemolymph vitellogenin levels during male phase and sex change in laboratory-maintained protandric shrimp, <Emphasis Type="Italic">Pandalus hypsinotus</Emphasis> (Crustacea: Caridea: Pandalidae)

Most pandalid shrimps show protandric hermaphroditism, and male sexual differentiation is considered to be controlled by the androgenic gland. In the present study, we examined the histology of gonadal development during the male phase and sex change and the involvement of the androgenic gland in regulating male reproduction in laboratory-maintained Pandalus hypsinotus. Juvenile shrimps developed testicular tissues in the peripheral part of gonads during the age of 16–31 months and produced spermatozoa between 34 and 36 months. After reaching sexual maturity, male shrimps exhibited seasonal testicular development: active production of spermatozoa (February–May), disappearance of spermatozoa (spent, April–June), increase of spermatocytes (May–November), appearance of spermatids and spermatozoa in the gonads (November–February). The androgenic gland cells became larger and the rough endoplasmic reticulum in the cytoplasm developed at male sexual maturity. The cell structure shows that the androgenic gland hormone is a peptide. Furthermore, bilateral eyestalk ablation on immature male shrimps induced hypertrophy of the androgenic gland and acceleration of male sexual maturation. These results indicate the involvement of androgenic gland hormone and some eyestalk factor in regulating male sexual maturation. Over a 1-year laboratory-rearing period, some male shrimps (16.7%) changed sex. In transitional shrimps, testicular tissues in the gonads and androgenic glands degenerated; on the other hand, oocytes started yolk protein accumulation and hemolymph vitellogenin levels became high. These results suggest that androgenic gland degeneration is a trigger for sex change and that the vitellogenin level is a useful marker for sex change.     

Emergy-based urban health evaluation and development pattern analysis

The objective of this study is to measure and evaluate the ecosystem health levels of 31 Chinese capital cities in 2004 through an emergy synthesis framework. A system of indicators was developed corresponding to the four factors of urban ecosystem health including efficiency, structure, impact and flux. Furthermore, combined with individual indices, an emergy-based urban ecosystem health index (EUEHI) was proposed to measure and evaluate the health levels among various typical cities in China, which offers an integrated evaluation tool in view of urban production, trade and consumption. The results showed that there are intrinsic differences among six clusters associated with driving mechanisms distinguishing the rankings of urban health levels. After lining the cities of similar health levels with cluster map, the spatial distribution of the urban health is found to be arch-shaped, increasing initially and then decreasing from coast to inner land. This kind of spatial hierarchy is per se compatible and consistent with the hierarchical theory of emergy synthesis. The results also revealed double restrictions of urban health between economy and environment. Moreover, the interaction analysis was used for mirroring the driving mechanism of urban ecosystem health. Three conclusions were arrived at. Firstly, environmental health is inversely related to the economic health in China, indicating that cities cannot achieve win–win between environment and economy in the current urban development mode. Secondly, based on economy-driven mode, four quadrants were divided in the city division map, wherein 43.33% of the concerned cities developed in high economy-restriction mode, which means low economic level is still an important limiting factor for the major cities of China. Finally, based on environment-driven mode, two sections were divided, of which weak environmental dominance mode expounds the special characteristics of urban environment with obvious fragility. 23.33% of the 30 cities were in the intermediate state, which means a few correspondingly unhealthy cities should develop concrete polices for the urban ecosystem restoration.     

Confirmation of serial spawning in the chokka squid Loligo vulgaris reynaudii off the coast of South Africa

Ovary maturation and spawning in the chokka squid Loligo vulgaris reynaudii were investigated by collecting squid from across their distributional range on the southeastern coast of South Africa between 1992 and 1993. Based on histological examination of the ovarian tissue and the separation of multiple modes in oocyte size-frequency distribution, ovary development was characterised by eight distinct stages. Our study confirms serial spawning in L. v. reynaudii. Received: 9 October 1998 / Accepted: 22 April 1999     

The impact on tropospheric ozone formation on the implementation of a program for mobile emissions control: a case study in São Paulo,Brazil

The main sources of reactive hydrocarbons (RHC) and nitrogen oxides (NO_x), ozone precursors, in the Metropolitan Area of São Paulo (MASP) in the southeast of Brazil are emissions from vehicles fleets. Ambient surface ozone and particulate matter concentrations are air quality problem in the MASP. This study examined the impact that implementing a control program for mobile emissions has on ozone concentrations, An episode of high surface ozone concentrations occurring in the MASP during the March 13–15, 2000 period was used as a case study that was modeled for photochemical oxidants using the California Institute of Technology/Carnegie Mellon University three-dimensional photochemical model. Different scenarios were analyzed in relationship to the implementation of the Programa Nacional de Controle de Poluição por Veículos Automotores (PROCONVE, National Program to Control Motor Vehicle Pollution). Scenario 1 assumed that all vehicles were operating within PROCONVE guidelines. Scenarios 2 and 3 considered hypothetical situations in which the PROCONVE was not implemented. Scenario 2 set the premise that vehicles were using pre-1989 technology, whereas scenario 3 allowed for technological advances. A base case scenario, in which the official emission inventory for the year 2000 was employed, was also analyzed. The CIT model results show agreement with most measurements collected during 13–15 March 2000 modeling episode. Mean normalized bias for ozone, CO, RHC and NO _x are approximately 9.0, 6.0, ?8.3, 13.0%, respectively. Tropospheric ozone concentrations predicted for scenario 2 were higher than those predicted for scenarios 1, 3 and base case. This study makes a significant contribution to the evaluation of air quality improvement and provides data for use in evaluating the economic costs of implementing a program of motor vehicle pollution control aimed at protecting human health.