Carbon dynamics in trees: feast or famine?

Research on the degree to which carbon (C) availability limits growth in trees, as well as recent trends in climate change and concurrent increases in drought-related tree mortality, have led to a renewed focus on the physiological mechanisms associated with tree growth responses to current and future climate. This has led to some dispute over the role of stored non-structural C compounds as indicators of a tree's current demands for photosynthate. Much of the uncertainty surrounding this issue could be resolved by developing a better understanding of the potential functions of non-structural C stored within trees. In addition to functioning as a buffer to reconcile temporal asynchrony between C demand and supply, the storage of non-structural C compounds may be under greater regulation than commonly recognized. We propose that in the face of environmental stochasticity, large, long-lived trees may require larger C investments in storage pools as safety margins than previously recognized, and that an important function of these pools may be to maintain hydraulic transport, particularly during episodes of severe stress. If so, survival and long-term growth in trees remain a function of C availability. Given that drought, freeze-thaw events and increasing tree height all impose additional constraints on vascular transport, the common trend of an increase in non-structural carbohydrate concentrations with tree size, drought or cold is consistent with our hypothesis. If the regulated maintenance of relatively large constitutive stored C pools in trees serves to maintain hydraulic integrity, then the minimum thresholds are expected to vary depending on the specific tissues, species, environment, growth form and habit. Much research is needed to elucidate the extent to which allocation of C to storage in trees is a passive vs. an active process, the specific functions of stored C pools, and the factors that drive active C allocation to storage.     

Reservoir fertilisation and fishery response in a highly managed reservoir with uncertain flows: Ecosystem-based management using decision analysis

Inland fisheries managers must account for multiple competing uses for aquatic resources; using methods such as ecosystem-based management allows for different priorities for aquatic ecosystems to be accounted for. Declining abundance of kokanee salmon Oncorhynchus nerka (Walbaum) in Arrow Lakes Reservoir in the 1990s led to the use of large-scale nutrient addition to improve productivity of kokanee and large piscivores. However, it is unclear what effect these measures had on the system given high discharge and highly variable annual flow regime throughout the watershed. An Ecopath with Ecosim model of the ecosystem was fitted to the available data and used to predict ecosystem structure and reservoir objectives under different nutrient addition strategies and varying annual flow regimes. Results from the model indicate that nutrient addition is an important driver in the system, with lower flows resulting in higher biomass for higher trophic levels. Decision analysis demonstrated the importance of maintaining nutrient additions to achieve management objectives despite losses in some high-flow years.     

Effects of Storing Pig Ovaries at 4 or 20°C for Different Periods of Time on the Morphology and Viability of Pre-Antral Follicles

The purpose of this study was to evaluate the effect of cooling ovarian tissue on pig pre-antral follicles. Ovaries were maintained in saline solution (0.9%) at 4 or 20 degrees C for 6, 12 or 18 h. After storage, pre-antral follicles were morphologically evaluated. While primordial follicles were not affected by the storage, the percentage of morphologically normal growing follicles was significantly reduced in ovarian tissue stored at 20 degrees C for 12 or 18 h. To test the viability of stored follicles, growing follicles isolated from ovaries stored at 4 degrees C for 18 h and at 20 degrees C for 6 h were cultured for 3 days. Follicles stored in either condition presented the same growth pattern in vitro as fresh follicles. We conclude that storage of pig ovaries at 4 degrees C for up to 18 h or at 20 degrees C for up to 6 h does not affect the morphology of growing follicles or their ability to grow in vitro.     

Groundfish species diversity and assemblage structure in Icelandic waters during recent years of warming

Elevated ocean temperatures have been predicted to lead to a poleward shift in the latitudinal distribution ranges of fish species. Different responses of fish species to increased temperatures might lead to changes in assemblage structure and local species richness. In this study, the assemblage structure and diversity of groundfish in Icelandic waters were examined using data from a standardized groundfish survey conducted annually in 1996–2007. We used hierarchical cluster analysis to define assemblages in two time periods and canonical correspondence analysis to explore the relationships between the assemblages and temperature, depth, latitude, longitude and year. We further used two estimates of diversity, species richness and the Shannon index. Four major species assemblages were identified. Assemblages in the hydrographically stable deep waters north of the country were consistent during the study, while assemblage structure in the more variable shallow waters underwent some changes. For this period of generally increasing sea temperature, the canonical correspondence analysis also revealed a shift towards species representative of warmer temperatures. Diversity was shown to be highly variable both temporally and spatially, and also to vary with depth and temperature. Species richness increased with temperature and time southwest of the country, but decreased northeast of the country. The different trends detected between the northern and southern areas illustrate the importance of performing analyses at the most appropriate scale.     

Canine intranasal tumours treated with alternating carboplatin and doxorubin in conjunction with oral piroxicam: 29 cases

Few veterinary studies have evaluated the response to chemotherapy treatment of canine intranasal tumours, while many have focused on the efficacy of radiation therapy. Given the higher costs and limited access to radiation therapy, alternative treatment options are needed. The study describes a cohort of dogs with histologically confirmed intranasal tumours treated with chemotherapy as a sole therapy. This retrospective study was conducted using data from the Melbourne Veterinary Specialist Centre (MVSC) database between 2004 and 2017. Dogs with a histologically confirmed intranasal tumour who received chemotherapy treatment were included. Signalment, presenting signs, tumour type, chemotherapy details, adverse events (AEs) and survival times were reviewed. Twenty‐nine dogs met the inclusion criteria. Overall median survival time for dogs in the study was 234 days (range 12‐1698 days). Median survival for dogs with adenocarcinoma or carcinoma (n = 12) was 280 days, transitional cell carcinoma (n = 6) 163 days, squamous cell carcinoma, anaplastic carcinoma or undifferentiated carcinoma (n = 7) 59 days and all sarcomas (n = 4) 448 days. Adverse events were reported following 28% of treatments and 69% of dogs experienced at least one AE. Twenty four per cent of all dogs experienced grade 3 or 4 toxicities. The chemotherapy protocol was generally well tolerated. The study suggests potential benefit in the use of chemotherapy for dogs with adenocarcinoma, carcinoma and sarcoma.     

Transdisciplinary research for supporting the integration of ecosystem services into land and water management in the Tarim River Basin,Xinjiang,China

There is a growing need for both science and practice domains to collaboratively and systematically seek knowledge-based strategies for sustainable development.In recent years,transdisciplinary research has emerged as a new approach that enables joint problem solving among scientists and stakeholders in various fields. In this paper,we aim to introduce transdisciplinary research for supporting the integration of the concept of ecosystem services into land and water management in the Tarim River Basin,Xinjiang,Northwest China.While a large number of ecosystem service studies have helped to raise the awareness for the value of nature in China,a number of challenges remain,including an improved understanding of the relationships between ecosystem structure, functions and services,and the interaction of the various ecosystem services.A meaningful valuation of ecosystem services also requires the consideration of their strong spatial heterogeneity.In addition,ways to introduce the concept of ecosystem services into decision-making in China need to be explored.Thus,successful integration of the concept of ecosystem services into actual land and water management requires a broad knowledge base that only a number of scientific disciplines and stakeholders can provide jointly,via a transdisciplinary research process.We regard transdisciplinary research as a recursive process to support adaptive management that includes joint knowledge generation and integration among scientists and stakeholders.System,target,and transformation knowledge are generated and integrated during the process of(1)problem(re)definition,(2)problem analysis and strategy development,and(3)evaluation of the impact of the derived strategy.Methods to support transdisciplinary research comprise participatory modelling(actor-based modelling and Bayesian Networks modelling)and participatory scenario development.Actor-based modelling is a semi-quantitative method that is based on the analysis of problem perspectives of individual stakeholders as depicted in perception graphs.With Bayesian Networks,complex problem fields are modelled probabilistically in a simplified manner,using both quantitative data and qualitative expert judgments.These participatory methods serve to integrate diverse scientific and stakeholder knowledge and to support the generation of actually implementable management strategies for sustainable development.For the purpose of integrating ecosystem services in land and water management in the Tarim River Basin through transdisciplinary research,collaboration among scientists and institutional stakeholders from different sectors including water,agriculture,forestry,and nature conservation is required.The challenge is to adapt methods of transdisciplinary research to socio-cultural conditions in China,particularly regarding ways of communication and decision-making.