Inland navigation and land use interact to impact European freshwater biodiversity

Inland navigation in Europe is proposed to increase in the coming years, being promoted as a low-carbon form of transport. However, we currently lack knowledge on how this would impact biodiversity at large scales and interact with existing stressors. Here we addressed this knowledge gap by analysing fish and macroinvertebrate community time series across large European rivers comprising 19,592 observations from 4,049 sampling sites spanning the past 32 years. We found ship traffic to be associated with biodiversity declines, that is, loss of fish and macroinvertebrate taxonomic richness, diversity and trait richness. Ship traffic was also associated with increases in taxonomic evenness, which, in concert with richness decreases, was attributed to losses in rare taxa. Ship traffic was especially harmful for benthic taxa and those preferring slow flows. These effects often depended on local land use and riparian degradation. In fish, negative impacts of shipping were highest in urban and agricultural landscapes. Regarding navigation infrastructure, the negative impact of channelization on macroinvertebrates was evident only when riparian degradation was also high. Our results demonstrate the risk of increasing inland navigation on freshwater biodiversity. Integrative waterway management accounting for riparian habitats and landscape characteristics could help to mitigate these impacts.

Multi-decadal improvements in the ecological quality of European rivers are not consistently reflected in biodiversity metrics

Humans impact terrestrial, marine and freshwater ecosystems, yet many broad-scale studies have found no systematic, negative biodiversity changes (for example, decreasing abundance or taxon richness). Here we show that mixed biodiversity responses may arise because community metrics show variable responses to anthropogenic impacts across broad spatial scales. We first quantified temporal trends in anthropogenic impacts for 1,365 riverine invertebrate communities from 23 European countries, based on similarity to least-impacted reference communities. Reference comparisons provide necessary, but often missing, baselines for evaluating whether communities are negatively impacted or have improved (less or more similar, respectively). We then determined whether changing impacts were consistently reflected in metrics of community abundance, taxon richness, evenness and composition. Invertebrate communities improved, that is, became more similar to reference conditions, from 1992 until the 2010s, after which improvements plateaued. Improvements were generally reflected by higher taxon richness, providing evidence that certain community metrics can broadly indicate anthropogenic impacts. However, richness responses were highly variable among sites, and we found no consistent responses in community abundance, evenness or composition. These findings suggest that, without sufficient data and careful metric selection, many common community metrics cannot reliably reflect anthropogenic impacts, helping explain the prevalence of mixed biodiversity trends.

Anthropogenic change decouples a freshwater predator's density feedback

Intraspecific interactions within predator populations can affect predator-prey dynamics and community structure, highlighting the need to better understand how these interactions respond to anthropogenic change. To this end, we used a half-century (1969-2018) of abundance and size-at-age data from Lake Erie's walleye (Sander vitreus) population to determine how anthropogenic alterations have influenced intraspecific interactions. Before the 1980s, the length-at-age of younger walleye (ages 1 and 2) negatively correlated with older (age 3 +) walleye abundance, signaling a 'density feedback' in which intraspecific competition limited growth. However, after the early 1980s this signal of intraspecific competition disappeared. This decoupling of the density feedback was related to multiple anthropogenic changes, including a larger walleye population resulting from better fisheries management, planned nutrient reductions to improve water quality and transparency, warmer water temperatures, and the proliferation of a non-native fish with novel traits (white perch, Morone americana). We argue that these changes may have reduced competitive interactions by reducing the spatial overlap between older and younger walleye and by introducing novel prey. Our findings illustrate the potential for anthropogenic change to diminish density dependent intraspecific interactions within top predator populations, which has important ramifications for predicting predator dynamics and managing natural resources.

Temporal scope influences ecosystem driver-response relationships: A case study of Lake Erie with implications for ecosystem-based management

Understanding environmental driver-response relationships is critical to the implementation of effective ecosystem-based management. Ecosystems are often influenced by multiple drivers that operate on different timescales and may be nonstationary. In turn, contrasting views of ecosystem state and structure could arise depending on the temporal perspective of analysis. Further, assessment of multiple ecosystem components (e.g., biological indicators) may serve to identify different key drivers and connections. To explore how the timescale of analysis and data richness can influence the identification of driver-response relationships within a large, dynamic ecosystem, this study analyzed long-term (1969-2018) data from Lake Erie (USA-Canada). Data were compiled on multiple biological, physical, chemical, and socioeconomic components of the ecosystem to quantify trends and identify potential key drivers during multiple time intervals (20 to 50 years duration), using zooplankton, bird, and fish community metrics as indicators of ecosystem change. Concurrent temporal shifts of many variables occurred during the 1980s, but asynchronous dynamics were evident among indicator taxa. The strengths and rank orders of predictive drivers shifted among intervals and were sometimes taxon-specific. Drivers related to nutrient loading and lake trophic status were consistently strong predictors of temporal patterns for all indicators; however, within the longer intervals, measures of agricultural land use were the strongest predictors, whereas within shorter intervals, the stronger predictors were measures of tributary or in-lake nutrient concentrations. Physical drivers also tended to increase in predictive ability within shorter intervals. The results highlight how the time interval examined can filter influences of lower-frequency, slower drivers and higher-frequency, faster drivers. Understanding ecosystem change in support of ecosystem-based management requires consideration of both the temporal perspective of analysis and the chosen indicators, as both can influence which drivers are identified as most predictive of ecosystem trends at that timescale.

Functional traits reveal the dominant drivers of long-term community change across a North American Great Lake

Ecosystems worldwide have been impacted by multiple anthropogenic stressors, yet efforts to understand and manage these impacts have been hindered by difficulties in disentangling relative stressor effects. Theoretically, the actions of individual stressors can be delineated based on associated changes in functional traits and these relationships should be generalizable across communities comprised of different species. Thus, combining trait perspectives with community composition data could help to identify the relative influence of different stressors. We evaluated the utility of this combined approach by quantifying shifts in fish species and trait composition in Lake Erie during the past 50 years (1969-2018) in relation to human-driven changes in nutrient inputs, climate warming, and biological invasions. Species and trait shifts were also compared between two Lake Erie basins, which differ in their environmental and biological characteristics, to identify trait responses that were generalizable across different ecosystems versus those that were context dependent. Our analyses revealed consistent species changes across basins, and shifts in feeding and thermal traits, that were primarily associated with altered nutrient inputs (oligotrophication followed by eutrophication). We found no or inconsistent trait-based evidence for the effects of warming and two invasive fishes. Context-dependent trait responses were also evident; nutrient inputs were related to shifts in species tolerant of turbidity in the shallow, eutrophic western basin, which contrasted to shifts between benthopelagic and benthic species in the deeper central basin. Our results reveal the dominant effects of specific stressors on a large freshwater lake and offer a framework for combining species-based and trait-based approaches to delineate the impacts of simultaneous stressors on communities of perturbed natural ecosystems.

The International Vertebrate Pet Trade Network and Insights from US Imports of Exotic Pets

The international trade in exotic vertebrate pets provides key social and economic benefits but also drives associated ecological, ethical, and human health impacts. However, despite its clear importance, we currently lack a full understanding of the structure of the pet trade, hampering efforts to optimize its benefits while mitigating its negative effects. In the present article, we represent and review the structure of the pet trade as a network composed of different market actors (nodes) and trade flows (links). We identify key data gaps in this network that, if filled, would enable network analyses to pinpoint targets for management. As a case study of how data-informed networks can realize this goal, we quantified spatial and temporal patterns in pets imported to the United States. Our framework and case study illustrate how network approaches can help to inform and manage the effects of the growing demand for exotic pets.

Projecting the effects of agricultural conservation practices on stream fish communities in a changing climate

How anticipated climate change might affect long-term outcomes of present-day agricultural conservation practices remains a key uncertainty that could benefit water quality and biodiversity conservation planning. To explore this issue, we forecasted how the stream fish communities in the Western Lake Erie Basin (WLEB) would respond to increasing amounts of agricultural conservation practice (ACP) implementation under two IPCC future greenhouse gas emission scenarios (RCP4.5: moderate reductions; RCP8.5: business-as-usual conditions) during 2020-2065. We used output from 19 General Circulation Models to drive linked agricultural land use (APEX), watershed hydrology (SWAT), and stream fish distribution (boosted regression tree) models, subsequently analyzing how projected changes in habitat would influence fish community composition and functional trait diversity. Our models predicted both positive and negative effects of climate change and ACP implementation on WLEB stream fishes. For most species, climate and ACPs influenced species in the same direction, with climate effects outweighing those of ACP implementation. Functional trait analysis helped clarify the varied responses among species, indicating that more extreme climate change would reduce available habitat for large-bodied, cool-water species with equilibrium life-histories, many of which also are of importance to recreational fishing (e.g., northern pike, smallmouth bass). By contrast, available habitat for warm-water, benthic species with more periodic or opportunistic life-histories (e.g., northern hogsucker, greater redhorse, greenside darter) was predicted to increase. Further, ACP implementation was projected to hasten these shifts, suggesting that efforts to improve water quality could come with costs to other ecosystem services (e.g., recreational fishing opportunities). Collectively, our findings demonstrate the need to consider biological outcomes when developing strategies to mitigate water quality impairment and highlight the value of physical-biological modeling approaches to agricultural and biological conservation planning in a changing climate.

Reciprocal human-natural system feedback loops within the invasion process

Biological invasions are inextricably linked to how people collect, move, interact with and perceive non-native species. However, invasion frameworks generally do not consider reciprocal interactions between non-native species and people. Non-native species can shape human actions via beneficial or detrimental ecological and socioeconomic effects and people, in turn, shape invasions through their movements, behaviour and how they respond to the collection, transport, introduction and spread of non-natives. The feedbacks that stem from this ‘coupled human and natural system’ (CHANS) could therefore play a key role in mitigating (i.e. negative feedback loops) or exacerbating (i.e. positive feedback loops) ongoing and future invasions. We posit that the invasion process could be subdivided into three CHANS that span from the source region from which non-natives originate to the recipient region in which they establish and spread. We also provide specific examples of feedback loops that occur within each CHANS that have either reduced or facilitated new introductions and spread of established non-native species. In so doing, we add to exisiting invasion frameworks to generate new hypotheses about human-based drivers of biological invasions and further efforts to determine how ecological outcomes feed back into human actions.

Stormwater ponds: An overlooked but plentiful urban designer ecosystem provides invasive plant habitat in a subtropical region (Florida, USA)

Designed ecosystems are built as part of ongoing urban expansion, providing a suite of valued ecosystem services. However, these new ecosystems could also promote disservices by facilitating the colonization and spread of invasive species. We conduct the first assessment of the quantity and invasion of an overlooked designed ecosystem: stormwater ponds. These ponds are commonly recommended for managing urban hydrology, but little is known about their ecology or extent of proliferation. Using a broad-scale survey of pond coverage in Florida, USA, we found that over 76,000 stormwater ponds have been built just in this state, forming 2.7% of total urban land cover. This extensive pondscape of manufactured habitats could facilitate species spread throughout urban areas and into nearby natural waterbodies. We also conducted a survey of the severity of plant invasion in 30 ponds in Gainesville, FL, US across two pond types (dry vs. wet), and a gradient of management intensities (low, medium, high) and pond ages. We unexpectedly found a high number of invasive plant species (28 in just 30 ponds). Ninety-six percent of surveyed ponds contained from one to ten of these species, with ponds exhibiting high turnover in invader composition (i.e., high beta diversity). The bank sections of dry unmanaged ponds exhibited the highest mean invasive species richness (5.8 ± 1.3) and the inundated centers of wet medium managed ponds exhibited the highest mean invasive species cover (34 ± 12%). Invasive plant richness and cover also tended to be greater in dry ponds with higher soil nutrient levels, and in older wet ponds. Therefore, we found that highly maintained and younger wet ponds were the least invaded. Nevertheless, common management practices that limit plant invasions may also limit native species establishment and invasion may increase in the decades following pond construction.

Developing a direct rating behavior scale for depression in middle school students

Research has supported the applied use of Direct Behavior Rating Single-Item Scale (DBR-SIS) targets of "academic engagement" and "disruptive behavior" for a range of purposes, including universal screening and progress monitoring. Though useful in evaluating social behavior and externalizing problems, these targets have limited utility in evaluating emotional behavior and internalizing problems. Thus, the primary purpose of this study was to support the initial development and validation of a novel DBR-SIS target of "unhappy," which was intended to tap into the specific construct of depression. A particular focus of this study was on the novel target's utility within universal screening. A secondary purpose was to further validate the aforementioned existing DBR-SIS targets. Within this study, 87 teachers rated 1,227 students across two measures (i.e., DBR-SIS and the Teacher Observation of Classroom Adaptation-Checklist [TOCA-C]) and time points (i.e., fall and spring). Correlational analyses supported the test-retest reliability of each DBR-SIS target, as well as its convergent and discriminant validity across concurrent and predictive comparisons. Receiver operating characteristic (ROC) curve analyses further supported (a) the overall diagnostic accuracy of each target (as indicated by the area under the curve [AUC] statistic), as well as (b) the selection of cut scores found to accurately differentiate at-risk and not at-risk students (as indicated by conditional probability statistics). A broader review of findings suggested that across the majority of analyses, the existing DBR-SIS targets outperformed the novel "unhappy" target. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Long-term behaviour of the free vascularised fibula following reconstruction of large bony defects

Thirty-two free vascularised fibula grafts performed at our unit have been assessed retrospectively with respect to success, bony union and percentage graft hypertrophy. Between 1981 and 1998, there were 21 males and 11 females (aged 8-61 years) with follow-up of 5 months to 14.6 years. The mean bony defect bridged was 12.0 cm (standard deviation 4.8; range 5.0-21.0 cm). Bony union and hypertrophy were assessed radiographically. Time to bony union was compared using the log-rank, Wilcoxon or likelihood ratio tests. Kaplan-Meier survival curves were constructed. Hypertrophy was compared with Wilcoxon's rank sum test.Three flaps failed. Seventy-four percent of patients healed primarily at a median time of 4.75 months; five patients required further surgery to heal by 18 months (interquartile range 14-20 months). Complication rate and donor site morbidity were low. The stress fracture rate was 21%. Ninety percent of patients regained a functional limb by 12 months.Hypertrophy was measured in 22 patients and ranged from 0 to 316% (median 71%; interquartile range 10-145%). Median hypertrophy in the lower limb was 76.5% (interquartile range 26.5-165%) compared to 33.5% in the upper limb (0-88%); p=0.16. Median hypertrophy in trauma cases was 80% (interquartile range 10-167%) compared to 70% in tumour cases (33-105%); p=0.62.Our findings confirm that the fibula responds physiologically to biomechanical loading. Our results compare well with other series and alternative reconstructive modalities. We conclude that the free fibula flap can provide excellent results in the salvage of limbs with large bony defects.

Pyoderma gangrensum--a complication of breast biopsy

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The use of near-infrared spectroscopy for assessing flap viability during reconstructive surgery

The ability to assess viability of tissues by monitoring changes in oxygenation and perfusion during harvesting and following transfer of free and pedicled flaps is potentially important in reconstructive surgery. Rapid detection of a critical change in tissue oxygenation could enable earlier and more successful surgical intervention when such problems arise. In this study near infra-red spectroscopy (NIRS) was used to assess changes in tissue oxygenation, haemoglobin oxygenation and blood volume in a porcine prefabricated myocutaneous flap model in response to pedicle manipulations. As far as we are aware this is the first usage of a NIRS instrument to assess changes in oxygenation in a flap model which closely simulates the clinical situation. A myocutaneous flap was raised (n = 9 pigs), tubed and the flap circulation allowed to readjust for periods between 7 and 9 days. The pedicle vessels were then subjected to arterial (n = 9), venous (n = 12) and total occlusion (n = 6). Repeatable and reproducible patterns of change were measured in each case. Comparison of mean values indicated that the differences between arterial and venous, and venous and total occlusions were significant for all NIRS parameters. The monitor was easily able to detect two additional features: (i) the presence of venous congestion indicated by raised levels of deoxygenated haemoglobin and an increase in blood volume; and (ii) the presence and magnitude of reactive hyperaemia. In two flaps release of arterial or total occlusion did not result in the expected reactive hyperaemia associated with an increase in blood volume (oxygenated haemoglobin) suggestive of possible damage to the vascular bed. NIRS proved able to detect and distinguish between microcirculatory changes occurring as a result of arterial, venous or total vascular occlusion. We believe that NIRS provides a sensitive and reliable postoperative monitor of tissue viability following transfer of free and pedicled flaps. It can accurately identify different types of problems with the pedicle vessels. In addition its predictive capabilities would allow assessment of flaps buried deep to the skin. This monitor is excellent for surgical and intensive care unit monitoring since it is unaffected by light, portable and is extremely easy to use.

Primary free-flap cover of open tibial fractures

Seventeen consecutive patients with Grade IIIB open tibial fractures had definitive treatment of both the fracture and soft tissues performed within 72 h of injury. Free tissue transfer was used for cover in each case. There were no cases of deep infection. Flap survival was 100 per cent. The mean time to fracture healing was 10 months, and mean time to walking unaided was 12 months. The average length of stay in hospital was 82 days. The findings suggest that immediate radical debridement followed by adequate soft tissue cover is a safe and effective method for treating these severe injuries.

Fatal inhalation injury following an industrial accident involving acetic anhydride

A 22-year-old man sustained 35 per cent burns to his skin and an inhalation injury in an industrial accident involving acetic anhydride. Although the skin burns healed following irrigation and conservative treatment, the inhalation injury proved fatal.

The sliding fasciocutaneous flap

A sliding fasciocutaneous flap on the medial side of the lower third of the leg is described. Its application in the management of skin defects in this area is illustrated.

Group amplification in schools for the hearing impaired

In the present field study, ambient noise levels and the status of group FM-wireless amplification systems were examined in 19 classrooms for the hearing impaired. Classroom noise was judged to be unacceptably high thus justifying the need for group amplification devices. Physical inspection of the group systems revealed defects in approximately one-half of the 28 teacher and 89 student amplification units. The electroacoustic measurements showed wide variability in performance among systems. There also appeared to be no systematic relationship between the degree of hearing loss of the children and the amount of unit gain being employed by each specific amplification system.

Electroacoustic performance characteristics of FM auditory trainers

This study investigated the electroacoustic performance characteristics of FM auditory trainers. Experiment one was designed to answer two interrelated questions. First, what are the differences in the electroacoustic performance of FM auditory trainers between the FM and EM modes? Second, is the method for evaluating electroacoustic performance of hearing aids also appropriate for assessing the response characteristics of FM auditory trainers? The purpose of the second experiment was to assess the effect that taper of the volume control dial had on performance of these trainers. The study found that, with certain cautions, the ANSI S3.22-1976 procedures for assessing a hearing aid could be applied to the measurement of FM trainers. There were performance differences, however, between the auditory trainers when set to the FM and EM transmission modes. Thus, the electroacoustic assessment of FM units in both the EM and FM modes of operation is needed to assess their performance fully.