Ultraviolet and temperature effects on planktonic rotifers and crustaceans in northern temperate lakes

1. Anthropogenic stressors such as climate change, ozone depletion and acidification may act in concert to alter ultraviolet (UV) light and temperature regimes in freshwater ecosystems. These physical and chemical changes will inevitably affect zooplankton community dynamics, but little is known about their relative effects on different species in natural communities. During spring, species that migrate to surface waters to take advantage of warmer temperatures may be especially vulnerable as UV levels can be high. 2. The objective of this study was to investigate the in situ effects of UV and temperature on a natural assemblage of planktonic rotifers and crustaceans during the spring. We performed in situ exposure experiments in two lakes with different surface temperatures. 3. Exposure to UV had a significant effect on the abundance and/or reproduction of four rotifers: Gastropus spp., Kellicottia bostonensis, Kellicottia longispina, Keratella spp.; two cladocerans: Holopedium gibberum, Daphnia catawba, and one copepod: Leptodiaptomus minutus. Incubation under cooler temperatures had a negative effect on K. longispina and H. gibberum. Temperature and UV had a significant interactive effect on abundance and/or reproduction of L. minutus and Ploesoma truncatum. Our results indicate that changes in underwater UV and temperature can significantly influence the composition of the zooplankton community and ultimately food web dynamics.     

新西兰银杏种质资源研究

新西兰位于南半球太平洋南部,介于南极洲和赤道之间,是目前为止南半球唯一一个将银杏作为产业来发展的国家。银杏在新西兰已有100多年的栽培历史,其南岛和北岛的各个城市和地区均栽植有银杏,但主要用作庭院、公园、街道绿化树种零星种植,直到21世纪初才开始被作为一种产业来发展。通过对新西兰的Auckland,Wellington,Hamilton,Hastings等主要城市的银杏种质资源进行广泛调查和定点观测,结果只发现有梅核类、佛指类、马铃类、园子类等四种类型。种核也较小,最大的为2.15g,最小的仅1.44g。本文主要报道了银杏在新西兰的栽培历史、生物学特性、种质资源及发展现状等,以期为中新两国开展在银杏方面的合作提供相关信息。     

Seasonal Habitat Associations of the Wolverine in Central Idaho

ABSTRACT Although understanding habitat relationships remains fundamental to guiding wildlife management, these basic prerequisites remain vague and largely unstudied for the wolverine. Currently, a study of wolverine ecology conducted in Montana, USA, in the 1970s is the sole source of information on habitat requirements of wolverines in the conterminous United States. The Montana study and studies conducted in Canada and Alaska report varying degrees of seasonal differences in wolverine habitat use. This article provides an empirical assessment of seasonal wolverine habitat use by 15 wolverines (Gulo gulo) radiotracked in central Idaho, USA, in 1992–1996. We controlled for radiotelemetry error by describing the probability of each location being in a habitat cover type, producing a vector of cover type probabilities suited for resource selection analysis within a logistic regression framework. We identified variables that were important to presence of wolverines based on their strength (significance) and consistency (variability in coeff. sign) across all possible logistic regression models containing 9 habitat cover types and 3 topographic variables. We selected seasonal habitat models that incorporated those variables that were strong and consistent, producing a subset of potential models. We then ranked the models in this subset based on Akaike's Information Criterion and goodness-of-fit. Wolverines used modestly higher elevations in summer versus winter, and they shifted use of cover types from whitebark pine (Pinus albicaulis) in summer to lower elevation Douglas fir (Pseudotsuga menziezii) and lodgepole pine (Pinus contorta) communities in winter. Elevation explained use of habitat better than any other variable in both summer and winter. Grass and shrub habitats and slope also had explanatory power. Wolverines preferred northerly aspects, had no attraction to or avoidance of trails during summer, and avoided roads and ungulate winter range. These findings improve our understanding of wolverine presence by demonstrating the importance of high-elevation subalpine habitats to central Idaho wolverines.     

Sexual dimorphism and tail-length in widowbirds and bishopbirds (Ploeeidae: Euplectes spp.): a reassessment

No evidence for sexual selection in the evolution of tail-length or wing-length in widow birds and bishopbirds (genus Euplectes ) was found when the methods used by previous authors were applied to a larger set of data. Nuptial tail-length dimorphism scaled with body size dimorphism except in Euplectes progne , and interpopulation variation in taillength could be explained by genetic drift alone. Wing-length appears to be under stabilizing selection and scales allometrically with body size, with no relation to tail-length unless E. progne is included in the analysis.     

The conservation of critically endangered flightless birds in New Zealand

The current status of Kakapo Strigops habroptilus and Takahe Porphyrio mantelli is described along with recent developments in programmes for their conservation. Both species were (at different times) thought to be effectively extinct, and both have been temporarily reprieved by the discovery of new populations. Population declines have continued, with Kakapo now reduced to less than 50 individuals and Takahe to about 150. Kakapo are especially at risk; 87% of the remaining birds are over 14 years old and only 17 females are known. Research on relict populations of both species has identified predation and competition from introduced mammals as major threats. Both species have high rates of egg infertility and low survival of young. Increasingly intensive management of both Kakapo and Takahe over recent years has included translocation to predator-free island refuges, supplementary feeding to encourage breeding, clutch manipulation, captive rearing and predator control. All known Kakapo have now been transferred to three island refuges, where the overall rate of population decline has slowed and supplementary feeding has apparently encouraged more frequent breeding attempts. Takahe conservation has concentrated largely on attempts to increase the population in Fiordland, New Zealand, through clutch manipulation and release of captive-reared young, but birds have also been released on four islands, which now hold 19% of the total population. The relict Fiordland populations of both Kakapo and Takahe were confined to apparently suboptimal habitat. Both species have successfully adapted to novel environments and foods when translocated, and the populations which now exist present improved opportunities for intensive management using a range of conservation techniques to enhance productivity and survival. Recent population trends of Kakapo and Takahe are reconstructed, and the contribution of research to their conservation is reviewed.     

Cultivar Differences in Starch Content and Protoplast Yields from Root Cortical Ex plants of Pisum salivum

Protoplasts were isolated from root cortical explants of thirteen cultivars of Pisum sativum. The roots were tested for starch in the cortical tissues. There was a considerable range in the average protoplast yields and the coefficient of variation of those yields from the thirteen cultivars. Cultivars with a higher incidence of starchy roots had lower average explam protoplast yields and greater variation in their protoplast yields. Significantly higher protoplast yields were observed from explants with no starch or few starchy cells. Increasing the germination time of the peas increased the starch content in the seedling roots and decreased the protoplast yields.     

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.