Occupancy in dynamic systems: accounting for multiple scales and false positives using environmental DNA to inform monitoring

Occupancy is an important metric to understand current and future trends in populations that have declined globally. In addition, occupancy can be an efficient tool for conducting landscape-scale and long-term monitoring. A challenge for occupancy monitoring programs is to determine the appropriate spatial scale of analysis and to obtain precise occupancy estimates for elusive species. We used a multi-scale occupancy model to assess occupancy of Columbia spotted frogs in the Great Basin, USA, based on environmental DNA (eDNA) detections. We collected three replicate eDNA samples at 220 sites across the Great Basin. We estimated and modeled ecological factors that described watershed and site occupancy at multiple spatial scales simultaneously while accounting for imperfect detection. Additionally, we conducted visual and dipnet surveys at all sites and used our paired detections to estimate the probability of a false positive detection for our eDNA sampling. We applied the estimated false positive rate to our multi-scale occupancy dataset and assessed changes in model selection. We had higher naïve occupancy estimates for eDNA (0.37) than for traditional survey methods (0.20). We estimated our false positive detection rate per qPCR replicate at 0.023 (95% CI: 0.016–0.033). When the false positive rate was applied to the multi-scale dataset, we did not observe substantial changes in model selection or parameter estimates. Conservation and resource managers have an increasing need to understand species occupancy in highly variable landscapes where the spatial distribution of habitat changes significantly over time due to climate change and human impact. A multi-scale occupancy approach can be used to obtain regional occupancy estimates that can account for spatially dynamic differences in availability over time, especially when assessing potential declines. Additionally, this study demonstrates how eDNA can be used as an effective tool for improved occupancy estimates across broad geographic scales for long-term monitoring.     

Stylet penetration by two aphid species on susceptible and resistant lettuce

The probing behavior of two aphid species, Myzus persicae (Sulz.) and Nasonovia ribisnigri (Mosley), was electronically monitored on susceptible and resistant lettuce lines using a DC amplifier. A waveform pattern associated with extracellular stylet pathway activities, pattern C, occurred for longer periods when either aphid species probed resistant plants. This pattern is usually regularly interrupted by drops in electrical potential lasting a few seconds, reflecting cell membrane punctures followed by rapid withdrawal of the stylet tips. For M. persicae on resistant lettuce a large increase in pattern C without these potential drops accounted for the increased duration of this pattern. For N. ribisnigri the increase in pathway activity on resistant plants was due to an increase in the more typical pattern C with potential drops, as well as to an increased duration of pattern F, associated with a curious type of stylet penetration within cell walls. Both aphids made more but shorter probes on resistant than on susceptible plants, and these probes led less frequently to periods of sieve element contact and ingestion. The effects of resistance appear to involve both mesophyll and phloem factors. The underlying mechanisms, however, remain unclear. The results indicate which stylet penetration activities or waveform patterns are of interest for further investigation of resistance mechanisms.

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Résumé Le comportement de sondage de variétés sensibles et résistantes de laitues par deux espèces de pucerons, Myzus persicae (Sulz.) et Nasonovia ribisnigri (Mosley), a été enregistré électroniquement en utilisant un amplificateur DC. Les deux espèces de pucerons ont présenté une amplification de l'onde de type C associée au cheminement extracellulaire des stylets lors du sondage des variétés résistantes. Cette onde est normalement interrompue par des chutes de quelques secondes du potentiel électrique, traduisant des ponctions de la membrane cellulaire suivies par un rapide retrait de l'extrémité des stylets. La forte augmentation de l'onde C mais sans chutes de potentiel rend compte de la plus longue durée de cette onde chez M. persicae sur laitue résistante. L'accroissement du cheminement des stylets chez N. ribisnigri sur plantes résistantes est dû à une augmentation de l'onde C typique avec chutes de potentiel, ainsi qu'à une prolongation de l'onde F liée à la pénétration des stylets dans les parois cellulaires. Les deux espèces font des sondages plus brefs et plus nombreux sur variétés résistantes, et ces sondages entraînent des contacts moins fréquents avec les éléments criblés et débouchent moins souvent sur de l'ingestion. Les effects de la résistance semblent impliquer des facteurs liés à la fois au mésophylle et au phloème. Les mécanismes sous-jacents, cependant, ne sont pas encore clairs. Ces résultats Montrent que l'examen des ondes liées à la pénétration des stylets est important pour des études ultérieures sur les mécanismes de résistance.

     

The valve movement response of mussels: a tool in biological monitoring

Biological sensors are becoming more important to monitor the quality of the aquatic environment. In this paper the valve movement response of freshwater (Dreissena polymorpha) and marine (Mytilus edulis) mussels is presented as a tool in monitoring studies. Examples of various methods for data storage and data treatment are presented, elucidating easier operation and lower detection limits. Several applications are mentioned, including an early warning system based on this valve movement response of mussels.     

Pollinosis in trentino (Northern Italy). Aerobiological and clinical research

Summary A study to evaluate and define the atmospheric pollen concentration in Trentino was carried out through the aerobiologic sampling in three localities chosen according to their different climatic conditions.1375 patients with pollinosis living in Trentino were studied retrospectively over the period ranging from 1986 to 1988 and selected according to the area they came from.Results have proved that the most allergenic pollen types are the following: Poaceae, Urticaceae (Parietaria), Compositae (Artemisia) and the tree pollen of Betulaceae and Corylaceae (Alnus, Betula, Corylus), and that pollinosis caused by such pollen, types has different features and frequencies according to the different localities.As far as symptoms are concerned, our data shows that rhinoconjuntivitis is more frequent in those patients who are allergic toParietaria while asthma results being more frequent in patients who are allergic to tree pollen.     

Responses to a stranger mother-son pair in the wild chimpanzee: A case report

A stranger mother-son pair of the chimpanzee was observed twice interacting with conspecifics of a neighbouring unit-group: first, when the mother and son accidentally encountered them within the core area of the former; second, when the mother and son temporarily immigrated for about one week. On both occasions, the mother and son were severely attacked by adult males of the neighbouring unit-group, and would have been killed had it not been for human intervention. The main target of the aggression was not the infant, but the mother. Some adult males intervened and prevented other males and females from attacking the mother-son pair. Moreover, most adult males displayed an ambivalent attitude since they showed aggression towards them on one occasion, but groomed, reassured and played on another. The reasons for the variable responses of adult males to a stranger female are discussed in terms of possible differences in their mating strategies.     

On-line monitoring of enzymes in downstream processing by flow injection analysis (FIA)

Flow injection analysis (FIA) has been employed to automate enzyme assays for formate dehydrogenase (FDH) and l-leucine dehydrogenase (l-LeuDH). Coupled to a special sampling device the FIA assays were used to monitor on-line downstream processes, e.g. disintegration of microbial cells and cross-flow filtration of cell homogenates.     

The efficacy of biobehavioral and compliance interventions in the adjunctive treatment of mild pregnancy-induced hypertension

This investigation assessed the efficacy of a biobehavioral intervention in the adjunctive treatment of mild pregnancy-induced hypertension (PIH), a potentially serious complication of pregnancy in which normotensive women develop hypertension, proteinuria, and edema of unknown etiology late in gestation. Forty-five women with symptoms of PIH were randomly assigned to one of three treatment conditions: bed rest alone (the most common obstetrical treatment), bed rest with individualized compliance enhancement training, or a four-session biobehavioral treatment consisting of bed rest, compliance enhancement training, and individualized thermal biofeedback-assisted relaxation training. Results indicated that while blood pressure for the bed rest and compliance enhancement groups continued to rise and pose an increasing health risk to maternal and fetal well-being, subjects in the biobehavioral group maintained their blood pressure at a significantly lower, and presumably safer, level. The biobehavioral treatment is hypothesized to affect blood pressure levels in subjects with mild PIH through the mediation of the sympathetic nervous system, decreasing peripheral vascular resistance and cardiac output. The results of this investigation suggest that the biobehavioral intervention may be an effective adjunct to bed rest in the treatment of mild PIH remote from term.     

Luminal responses to bradykinin on the isolated canine tracheal epithelium: effects of bradykinin antagonists

We have tested the ability of several B₂ antagonists on the responses of the open-circuited isolated canine tracheal epithelium to the luminal addition of Bradykinin (BK), Lys-BK, and substance P (SP). All three peptides produced biphasic changes in transmural potential difference (PD), an initial decrease (dip) followed by an increase (rise). The B₂ antagonists -Arg^o [Hyp³,Thi^5,8, -Phe⁷]BK (B5630) reversibly inhibited both the dips and the rise with IC₅₀ values of 2.01 · 10⁻⁸ and 1.54 · 10⁻⁷ M, respectively. The responses to SP were unaffected even with high concentrations of the antagonist. Other antagonists tested [ -Phe^1,7,Thi^5,8]BK (B4158), [ -Phe^2,7]BK (B4404), and [ -Phe⁷,Hyp⁸]BK (B5092) were ineffective.