Understanding and predicting ecological dynamics: are major surprises inevitable?

Ecological surprises, substantial and unanticipated changes in the abundance of one or more species that result from previously unsuspected processes, are a common outcome of both experiments and observations in community and population ecology. Here, we give examples of such surprises along with the results of a survey of well-established field ecologists, most of whom have encountered one or more surprises over the course of their careers. Truly surprising results are common enough to require their consideration in any reasonable effort to characterize nature and manage natural resources. We classify surprises as dynamic-, pattern-, or intervention-based, and we speculate on the common processes that cause ecological systems to so often surprise us. A long-standing and still growing concern in the ecological literature is how best to make predictions of future population and community dynamics. Although most work on this subject involves statistical aspects of data analysis and modeling, the frequency and nature of ecological surprises imply that uncertainty cannot be easily tamed through improved analytical procedures, and that prudent management of both exploited and conserved communities will require precautionary and adaptive management approaches.     

18S rRNA phylogeny of sea spiders with emphasis on the position of Rhynchothoracidae

The phylogenetic relationships among all living families of sea spiders (Arthropoda: Pycnogonida) are investigated using nearly complete 18S rRNA sequences from 57 ingroup species and five chelicerates under the Bayesian and maximum likelihood methods. Monophyly of Colossendeidae, Pycnogonidae, Phoxichilidiidae, Endeidae and Pallenopsidae is consistently supported. However, the genera formerly classified in the family Ammotheidae are split up into two distantly related groups. The genera Ascorhynchus and Eurycyde (here recognized as Ascorhynchidae) are possibly an early offshoot of sea spiders, whereas other ammotheids constitute a robust terminal clade with Pallenopsidae, Phoxichilidiidae and Endeidae. This topology also opposes the prevalent assumption of successive losses and simplification of three kinds of cephalic appendages like in a previous cladistic analysis. At least three independent losses are suggested for palps by the inferred topology, and both chelifores and female ovigers may have been lost twice. Our knowledge of early ontogeny and internal anatomy is more congruent with the present 18S rRNA data. The families Callipallenidae and Nymphonidae with unique “attaching larvae” are grouped together in present molecular trees, suggesting that extended paternal care of offspring evolved only once in Pycnogonida. Confident clustering of Pycnogonidae and Rhynchothoracidae indicates that the number of female genital pores is an evolutionary conservative character.     

Sperm traits in the quacking frog (<Emphasis Type="Italic">Crinia georgiana</Emphasis>), a species with plastic alternative mating tactics

In species where males use alternative reproductive tactics and male phenotypes are confronted with different risks of sperm competition, theory predicts that between-male-type differences in sperm expenditure may evolve. In the frog Crinia georgiana big males can monopolize females, whereas small males often engage in polyandrous matings. Consequently, big males may experience a lower risk of sperm competition than do small males. We tested if the predictions from theoretical models can be applied to the mating system of C. georgiana. Our results showed that small males do not have larger testes relative to their body size compared to their larger counterparts and that the efficiency with which sperm number, size, motility, and longevity are produced by the testes does not differ between small and large males in the predicted way. These results are not in alignment with predictions from a loaded raffle model of sperm competition on sperm expenditure in males with alternative phenotypes. The plasticity in mating tactics used by C. georgiana males and a high intraseasonal variation in male densities may have prevented the evolution of enhanced sperm performance in smaller males. A fair raffle in the sperm competition game played by C. georgiana males could also explain the observed patterns in sperm traits. Future investigations determining the parameters responsible for the deviation from theoretical predictions in this system will test the degree to which current theoretical models can indeed be applied to species with plastic reproductive tactics.     

水浴消解－原子荧光法同时测定污水处理厂污泥中的汞和砷

本文主要介绍了应用双道原子荧光光谱法,采用水浴消解法同时测定污水处理厂污泥中汞和砷的原理和过程。结果表明,该方法具有操作简单、快速省事、灵敏度高、准确度好、节省试剂等优点,是较好的测定方法。     

Metal ferrite incorporated polysulfone thin-film nanocomposite membranes for wastewater treatment

Effluents from food, fermentation, and sugar industries contain a large quantity of glucose which has to be removed to limit the chemical oxygen demand (COD) of the water discharged. This work proposes novel thin-film nanocomposite (TFN) membranes incorporated with MgFe₂O₄ and ZnFe₂O₄ nanoparticles to address this concern. The nanoparticles synthesized by the sol–gel method was extensively characterized and then incorporated into the active polyamide layer of the thin-film composite polysulfone membranes. The change in membrane morphology, wettability, chemical structure, and mechanical strength with the incorporation of nanoparticles was studied in detail. Membranes with 0.005 wt.% MgFe₂O₄ nanoparticle exhibited highest glucose rejection (96.52?±?2.35%) at 10 bar, 25 °C, and sufficiently high pure water flux (50.54?±?1.92 L/m²h). This membrane also displayed 69.1?±?5.12% salt rejection when challenged with 2000 ppm synthetic NaCl solution.

     

On the uncertainty and confidence in decision support tools (DSTs) with insights from the Baltic Sea ecosystem

Ecosystems around the world are increasingly exposed to multiple, often interacting human activities, leading to pressures and possibly environmental state changes. Decision support tools (DSTs) can assist environmental managers and policy makers to evaluate the current status of ecosystems (i.e. assessment tools) and the consequences of alternative policies or management scenarios (i.e. planning tools) to make the best possible decision based on prevailing knowledge and uncertainties. However, to be confident in DST outcomes it is imperative that known sources of uncertainty such as sampling and measurement error, model structure, and parameter use are quantified, documented, and addressed throughout the DST set-up, calibration, and validation processes. Here we provide a brief overview of the main sources of uncertainty and methods currently available to quantify uncertainty in DST input and output. We then review 42 existing DSTs that were designed to manage anthropogenic pressures in the Baltic Sea to summarise how and what sources of uncertainties were addressed within planning and assessment tools. Based on our findings, we recommend future DST development to adhere to good modelling practise principles, and to better document and communicate uncertainty among stakeholders.Electronic supplementary materialThe online version of this article (doi:10.1007/s13280-020-01385-x) contains supplementary material, which is available to authorized users.     

Evaluation of risk and cost using an age-dependent unavailability modelling of test and maintenance for standby components

The improvement of safety in the process industries is related to assessment and reduction of risk in a cost-effective manner. This paper addresses the trade-off between risk and cost related to standby safety systems. An age-dependent unavailability model that integrates the effects of the test and maintenance (T&M) activities as well as component ageing is developed and represents the basis for calculating risk. The repair “same-as-new” process is considered regarding the T&M activities. Costs are expressed as a function of the selected risk measure. The time-averaged function of the selected risk measure is obtained from probabilistic safety assessment, i.e. the fault tree analysis. This function is further extended with inclusion of additional parameters related to T&M activities as well as ageing parameters related to component ageing. In that sense, a new model of system unavailability, incorporating component ageing and T&M costs, is presented. The testing strategy is also addressed. Sequential and staggered testings are compared. The developed approach is applied on a standard safety system in nuclear power plant although the method is applicable to standby safety systems that are tested and maintained in other industries as well. The results show that the risk-informed surveillance requirements differ from existing ones in technical specifications, which are deterministically based. Moreover, the presented approach achieves a significant reduction in system unavailability over a relatively small increase of total T&M costs.     

Expansion of Nature Conservation Areas: Problems with Natura 2000 Implementation in Poland?

In spite of widespread support from most member countries’ societies for European Union policy, including support for the sustainable development idea, in many EU countries the levels of acceptance of new environmental protection programmes have been and, in particular in new member states, still are considerably low. The experience of the countries which were the first to implement union directives show that they cannot be effectively applied without widespread public participation. The goal of this study was, using the example of Poland, to assess public acceptance of the expansion of nature conservation in the context of sustainable development principles and to discover whether existing nature governance should be modified when establishing new protected areas. The increase in protected areas in Poland has become a hotbed of numerous conflicts. In spite of the generally favourable attitudes to nature which Polish people generally have, Natura 2000 is perceived as an unnecessary additional conservation tool. Both local authorities and communities residing in the Natura areas think that the programme is a hindrance, rather than a help in the economic development of municipalities or regions, as was initially supposed. This lack of acceptance results from many factors, mainly social, historic and economic. The implications of these findings for current approach to the nature governance in Poland are discussed.     

A Bayesian approach for understanding the role of ship speed in whale-ship encounters

Mandatory or voluntary reductions in ship speed are a common management strategy for reducing deleterious encounters between large ships and large whales. This has produced strong resistance from shipping and marine transportation entities, in part because very few studies have empirically demonstrated whether or to what degree ship speed influences ship-whale encounters. Here we present the results of four years of humpback whale sightings made by observers aboard cruise ships in Alaska, representing 380 cruises and 891 ship-whale encounters. Encounters occurred at distances from 21 m to 1000 m (x = 567 m) with 61 encounters (7%) occurring between 200 m and 100 m, and 19 encounters (2%) within 100 m. Encounters were spatially aggregated and highly variable across all ship speeds. Nevertheless a Bayesian change-point model found that the relationship between whale distance and ship speed changed at 11.8 knots (6.1 m/s) with whales encountering ships, on average, 114 m closer when ship speeds were above 11.8 knots. Binning encounter distances by 1-knot speed increments revealed a clear decrease in encounter distance with increasing ship speed over the range of 7-17 knots (3.6-8.7 m/s). Our results are the first to demonstrate that speed influences the encounter distance between large ships and large whales. Assuming that the closer ships come to whales the more likely they are to be struck, our results suggest that reduced ship speed may be an effective management action in reducing the probability of a collision.