Years Of Monitoring Data Research Articles

Identifying marine invasion hotspots using stacked species distribution models

Early detection and management of aquatic invasive species requires identification of those areas most at risk of invasion (i.e., hotspots). Here we identify present-day and future hotspots of invasion risk for marine invertebrates and algae in nearshore habitats of the northwest Atlantic and northeast Pacific using more than 12 years of monitoring data in conjunction with other occurrence data and stacked species distribution models. The stacked species distribution models predicted the general patterns of observed invasive species richness in both study areas (Atlantic: r2 = 0.52, Pacific: r2 = 0.42). In the northwest Atlantic, we identified hotspots through much of Massachusetts, New Hampshire and southern Maine, and in several bays in southwestern New Brunswick and Nova Scotia. In the northeast Pacific, much of the southern Salish Sea was identified as a hotspot, as were a few areas along the outer coast of Washington and Oregon. Projecting our species distribution modelling results to 2075 (climate scenario RCP 8.5), we found that existing hotspots are likely to expand slightly in the Atlantic, while in the Pacific existing hotspots are predicted to shift or expand, new hotspots are likely to appear, and areas with few invasive species attaining moderate invasive species richness. Our results suggest that climate change will have larger effects on the distributions of our focal invasive species on the Pacific coast compared to the Atlantic. Resultant hotspot maps provide an integrated perspective and guidance to managers tasked with prioritizing locations for monitoring and implementing policy related to marine invasive species, with projected hotspots making planning for future changes in invasion risk possible.

Quantitative Flow‐Ecology Relationships Using Distributed Lag Nonlinear Models: Large Floods in the Murray River Could Have Delayed Effects on Aquatic Macroinvertebrates Lasting More Than Three Decades

AbstractWe aimed to quantify the delayed effects of flows on aquatic ecosystems using 33 years of monitoring data on macroinvertebrates and water quality and 51 years of hydrological data, spanning 2,300 km of the Murray River, Australia. By incorporating the delayed effects of hydrological indices, along with physicochemical variables, into generalized additive models to form distributed lag nonlinear models for macroinvertebrate richness and abundance, we found that the effects of floods on macroinvertebrates could last up to 32 years, depending on their magnitude. The models indicated that a large flood can cause an initial depression in macroinvertebrate abundance and richness, followed by a sustained increase persisting for over 25 years before returning to preflood levels. Twelve hydrological indices representing the magnitude of flow events were evaluated, with the q90/med (the 6‐monthly flow exceeded 10% of time, divided by the long‐term median) performing (slightly) better than other indices. Competing hypotheses for the mechanisms underlying the apparent long‐term effect of floods were considered, with the most plausible explanation being the flood‐mediated influx of allochthonous organic matter, especially coarse and large woody debris, that might drive the persistent change in the aquatic community. It is generally believed that macroinvertebrate communities recover quickly after floods, but our findings suggest that we may need to reconceptualize the effects that floods can have on aquatic macroinvertebrates and the communities they support, especially in the context of flow restoration and climate change.

Biological response to 5 years of operations of cascade rubber dams in a plateau urban river, China

AbstractAquatic ecosystem response to dam construction and operation is an important concern, but systematic assessment of impacts induced by cascade small rubber dams are seriously lacking. In this study, the Huangshui River in Qinghai Province was selected to investigate biological response to small cascade rubber dams. Two years of monitoring data in 2018 and 2019 were utilized to quantify the variation of five kinds of aquatic organisms. Results indicate continuous rubber dams produced significant changes to hydrological regimes of rivers, especially for high flow seasons, and further affect aquatic biological populations and structures of the river. (a) The biodiversity and biomass of plankton increased by 8.0 times and 1.8 times, respectively; the biomass of fish and benthic animals were enhanced by 3.2 and 2.1 times, respectively, but the species richness decreased by 30% on average. Native fish are completely replaced by exotic fish, and benthic animals are changing towards singularity; (b) The surface and bottom food chains of the river gradually become dominant, and the disappearance of native fish in the middle layer caused the exchange flow in the middle layer to decrease rapidly, which leads to a dumbbell‐shaped distribution structure of biomass; (c) The regulation services of rivers have also undergone huge changes. N2O and CH4 emissions from dammed areas have increased by 10.1 times, and the water purification function varied in different dammed areas.

Trends in water quality in a subtropical Australian river-estuary system: Responses to damming, climate variability and wastewater discharges

The Logan-Albert estuary in southeast Queensland, Australia, has high biodiversity and supports multiple economic and recreational services. Elevated nutrient and sediment loads have been a longstanding management issue for the estuary. We investigated the spatial and seasonal patterns of nutrients and turbidity along the Logan-Albert estuary and assessed the effects of a recently constructed upstream dam. Nutrient concentrations and turbidity levels were analysed using 15 years of monitoring data from 19 water quality sites throughout the estuary. We hypothesised that the construction of Wyaralong Dam would act as a nutrient and sediment sink which may have positive effects on downstream water quality. Long-term trends of water quality constituents were evaluated using a non-parametric seasonal Mann-Kendall test and the effect of upstream impoundment was assessed with a Before-After Control-Impact (BACI) test. Nutrient concentrations and turbidity levels declined significantly with time in the upper Logan estuary and, to a lesser extent, in the lower Albert estuary. The general improvement of water quality in the upper Logan estuary was attributed to construction of the Wyaralong Dam. Significant decreases in concentrations of total phosphorus (TP) and oxidised nitrogen (NOx-N) along the lower Albert were principally attributed to wetter conditions over the 15-year dataset, which diluted point-source loads from a nearby wastewater treatment plant (WWTP). Our results show that estuarine water quality changes can be highly dynamic with interactions amongst climate and management practices that necessitate long-term monitoring programs with good spatial coverage.

Deformation characteristics and reactivation mechanisms of the Outang ancient landslide in the Three Gorges Reservoir, China

This paper presents an in-depth analysis of the deformation characteristics and reactivation mechanisms of a giant ancient translational landslide in the Three Gorges Reservoir (TGR) based on more than 6 years of monitoring data with the assistance of in situ surveys. The Outang landslide, divided into three active parts, has a total volume of approximately 90 million m3 and slides along weak interlayers (WIs). Since the impoundment, the landslide has been experiencing persistent deformations with some distinct movement signs. The temporal displacements are marked by seasonal cycles of fast displacements in the summer followed by almost imperceptible movements for the remainder of each hydrologic year. The spatial displacement rates gradually increased with the increase in altitude. The primary triggering factors for slope movement could transition from the drawdown of the reservoir water to the periodic rainfall. The affected areas by the former and latter are mainly concentrated in the front part and the upper part of the slope, respectively. The landslide exhibited a composite push-retrogression-type failure evolution with the fluctuating reservoir levels destabilizing rock masses at the front part of the landslide and the precipitation mainly mobilizing materials in the upper part of the slope. Currently, the landslide is in a state of continuous movement. The toe area and upper part of the landslide should receive high priority for the development of preventative measures.

Characterizing the phytoplankton and zooplankton communities in Kootenay Lake: a time series analysis of 24 years of nutrient addition

Large-scale seasonal addition of limiting nutrients has been used for restoration in Kootenay Lake, British Columbia, since 1992 to mitigate cultural oligotrophication resulting from upstream hydropower development, river channelization, mysid shrimp introduction, and extensive tributary floodplain loss. Historical (1949) in-lake nutrient levels were targeted to stimulate bottom-up carbon transfer from native plankton communities to planktivorous and piscivorous fish populations that support popular fisheries. Analysis of 24 years of monitoring data assessed the effects of nutrient addition on the phytoplankton and zooplankton communities. Assessment involved comparisons of plankton community metric data from North Arm (1992–2003) and North + South arms (2004–2015) nutrient addition periods. A before–after, control–impact (BACI) analysis adjusted for these effects involved a series of phytoplankton and zooplankton metrics across the two lake arms. Time series analyses revealed significant serial correlation structure, significant increases in phytoplankton and zooplankton abundance and biomass, and increased stability within the phytoplankton and zooplankton communities. Results confirmed that adaptively managed nutrient restoration can effectively restore biological productivity and community structure in a large culturally oligotrophic lake.

Long-term Performance and Costs for the Anna S Mine Passive Treatment Systems

AMD from the Anna S coal mine in Pennsylvania (USA) has been treated successfully since 2004 in the Anna and Hunters Drift (HD) passive systems. The systems, which consist of vertical flow ponds and constructed wetlands, are the largest and most costly mine water treatment project installed by a non-profit group in the USA to date. 15 years of monitoring data show that the systems effectively treated 1910 L/min of flow with pH 2.8–3.1 containing 121–330 mg/L acidity (as CaCO3), 11–31 mg/L Al, 6–33 mg/L Fe, and 6 mg/L Mn. The systems produced effluents with pH 7.5, 134–140 mg/L alkalinity (as CaCO3), < 1 mg/L Al, 1 mg/L Fe, 2–3 mg/L Mn, and never discharged water with less than 60 mg/L alkalinity (106 samples). In 15 years of operation, the systems generated a combined 5600 tonnes (t) of net alkalinity. Unit treatment costs were converted to 2018 U.S. $ and compared to active treatment systems. Over a 20 year period, passive systems generate alkalinity at a cost of $1168/t of CaCO3, which is 50% less than unit costs for lime treatment plants currently operated in Pennsylvania.

Submerged Vegetation Responses to Climate Variation and Altered Hydrology in a Subtropical Estuary: Interpreting 33 Years of Change.

Links between hydrologic modifications, flow and salinity regimes, and submerged aquatic vegetation (SAV) species composition and abundance were assessed with an empirical analysis of 33 years of monitoring data collected at nine sites in Florida's Caloosahatchee River Estuary (CRE). Freshwater inflows to the estuary (30-day means) were often outside the previously recommended envelope of 12.74 to 79.29 m3 s-1. Discharges from Lake Okeechobee through a synthetic hydrologic link were responsible for 43% of the above-envelope flows, but reduced the incidence of below-envelope flows by 30%. A salinity model and salinity stress indices developed for each SAV species indicated that the observed flows generated variable salinity conditions likely to harm both seagrasses and freshwater SAV in the estuary. Regression modeling of SAV abundance generally confirmed the flow and salinity responses expected for each species: Halodule wrightii and Thalassia testudinum in the lower estuary were both harmed by high-flow, low-salinity conditions, while Vallisneria americana in the upper estuary was decimated by low-flow, high-salinity conditions. There was a species-specific effect of the seasonal timing of high flows-T. testudinum was more negatively correlated with high flows in the dry season; H. wrightii in the wet season. The regression analyses also highlighted strong, year-to-year autocorrelations in SAV abundance, indicating reduced resilience after severe losses, particularly for V. americana. Large residual variation in some regression models suggested that factors other than salinity (e.g., optical water quality or grazing impacts) may also influence the system dynamics and should be incorporated in continuing research. This analysis suggests that use of artificial water management infrastructure to reduce extreme high and low flows to the Caloosahatchee and other estuaries could help maintain SAV health in light of intensifying climate variability and degraded watershed flow regulation capacity.

Effects of rainfall and terracing-vegetation combinations on water erosion in a loess hilly area, China

Terracing and vegetation restoration are the basic measures to protect soil from water erosion and to combat land degradation. However, long-term quantitative evaluation on the erosion control benefits of different terracing techniques and vegetation types are still insufficient, particularly under variable rainfall. The aim of this article, therefore, is to evaluate the coupling effects of different terracing-vegetation combinations and rainfall types (RTs) on runoff retention and erosion reduction in a loess hilly catchment of China. Six types of terracing-vegetation combinations, including leveled benches-C. microphylla (LM), fish-scale pits-P. orientalis (FO), leveled ditches-P. armeniaca (LA), zig terraces-P. orientalis (ZO), fish-scale pits-P. tabulaeformis (FT), zig terraces-P. tabulaeformis (ZT) and the corresponding plots with same vegetation cover and non-terracing measures were designed and monitored. Based on five consecutive years of monitoring data, 69 rainfall events causing runoff and erosion were observed. Rainfall eigenvalues, including rainfall amount (RA), maximum 10-min intensity (I10), maximum 30-min intensity (I30) and rainfall duration (RD) dominated water erosion processes. Surface runoff and sediment reduction benefits differed with different terracing techniques. Mean runoff coefficients (Rc) among all kinds of terracing-vegetation combinations were FT > LM > FO > LA > ZO > ZT, while mean soil loss rates (Em) among all kinds of combinations were FT > FO > LM > LA > ZT > ZO. ZT showed the highest mean runoff reduction (44.03%), while ZO generated the highest sediment reduction (39.08%). The worst performance was observed in FT. With regards to the results, it is necessary to select the optimal terracing-vegetation measures for erosion control based on the dominant rainfall eigenvalues in different areas. Overall, ZT, ZO and LA combinations are recommended, while uncertainty was detected in combinations with fish-scale pits. Suitable terracing-vegetation measures should be selected after considering the micro-relief construction, the optimization of plant disposition and the efficiency of water erosion reduction. Management should focus on the construction standards, the threshold of resisting erosion for each terracing measure, and timely maintenance of the terraces.

Turning Routine Data into Systems Insight: Multivariate Analysis of Water Quality Dynamics in a Major Drinking Water Reservoir

Long-term water quality datasets generated by the routine monitoring activities of public water supply utilities are often under-utilized in terms of the information they contain regarding system dynamics. This study demonstrates the insight that may be derived from thorough analysis of such data, in terms of evaluating key factors underlying spatial and temporal patterns in the water quality of major storage reservoirs. Principal component (PCA) and multivariate curve resolution-alternating least squares (MCR-ALS) analyses were applied to three consecutive years of monitoring data, comprising 22 physicochemical parameters, measured at three sampling stations within a major drinking water reservoir. Reservoir nitrogen levels were found to be most strongly influenced by urban run-off from the south-eastern catchment region, while total phosphorus levels were more closely linked to inflows to the northern end of the reservoir from the mainly agricultural neighbouring catchment. Elevations in soluble reactive phosphorus (SRP) were correlated with increases in the vertical temperature gradient of the water column at the relatively shallow northern end, suggesting possible release from sediments as a major source. SRP and thermal gradient, as opposed to absolute water temperature, were found to be the factors most closely aligned with chlorophyll-α levels in the reservoir. The analyses highlighted the catchment origins and in-storage foci of key factors driving algal productivity within the reservoir, suggesting that water quality management strategies may be further informed by investigation of sediment characteristics and interplay between physical, chemical and biological processes at the northern end of the reservoir.

Long-term observations from Antarctica demonstrate that mismatched scales of fisheries management and predator-prey interaction lead to erroneous conclusions about precaution

Low catch limits for forage species are often considered to be precautionary measures that can help conserve marine predators. Difficulties measuring the impacts of fisheries removals on dependent predators maintain this perspective, but consideration of the spatio-temporal scales over which forage species, their predators, and fisheries interact can aid assessment of whether low catch limits are as precautionary as presumed. Antarctic krill are targeted by the largest fishery in the Southern Ocean and are key forage for numerous predators. Current krill removals are considered precautionary and have not been previously observed to affect krill-dependent predators, like penguins. Using a hierarchical model and 30+ years of monitoring data, we show that expected penguin performance was reduced when local harvest rates of krill were ≥0.1, and this effect was similar in magnitude to that of poor environmental conditions. With continued climate warming and high local harvest rates, future observations of penguin performance are predicted to be below the long-term mean with a probability of 0.77. Catch limits that are considered precautionary for forage species simply because the limit is a small proportion of the species’ standing biomass may not be precautionary for their predators.

Tree cavity abundance and beyond: Nesting and food storing sites of the pygmy owl in managed boreal forests

Natural cavities are a critical resource for non-excavating hole-nesting birds, many of which are declining in northern Europe. In the heavily managed boreal forests in Finland, cavities may be a scarce resource, but their availability to different hole-nesters has been examined in only a few studies. We studied the abundance of suitable cavities in two managed forest landscapes 300 km apart for a forest-dwelling predator, the Eurasian Pygmy Owl Glaucidium passerinum, which requires tree cavities for both nesting and food hoarding. We further examined the preferences of the owls for different cavity characteristics in two experiments and several years of monitoring data with nest boxes resembling natural cavities. We found that natural cavities were scarce in the landscape (6.5/km2). However, natural cavity abundance per se does not seem to limit the breeding density of this predator, as suggested by a low occupancy rate in natural cavities and nest boxes. Owls cleaned the cavities that were filled with nest material of other birds, which provides a greater number of possible cavities to choose from. Cavities whose characteristics prevent the nest from being reached by predators were clearly preferred, as the owls select cavities with more than 5 cm width of the front wall and 15–30 cm of entrance-bottom distance within the cavity. The entrance hole orientation or the height of the cavity from the ground did not affect cavity occupancy by pygmy owls for nesting. In addition, none of the characteristics of the cavities that we surveyed affected their use for food hoarding. While the number of cavities per se may not limit the nesting of the owls, they may be limited by suitable habitat with abundant food supply around available cavities, or by lack of cavities in suitable habitats. They also need more cavities in the winter than in the summer, as each individual needs one to six cavities for hoarding food to survive over winter. Effective conservation strategies for this forest specialist should therefore include the maintenance of high-quality habitat that contains suitable cavities, supporting the need for protection of mature and old-growth forests as a whole, and not just of cavity bearing trees alone.

Dictionary Learning Approach to Monitoring of Wind Turbine Drivetrain Bearings

Condition monitoring is central to the efficient operation of wind farms due to the challenging operating conditions, rapid technology development and large number of aging wind turbines. In particular, predictive maintenance planning requires the early detection of faults with few false positives. Achieving this type of detection is a challenging problem due to the complex and weak signatures of some faults, particularly the faults that occur in some of the drivetrain bearings. Here, we investigate recently proposed condition monitoring methods based on unsupervised dictionary learning using vibration data recorded over 46 months under typical industrial operations. Thus, we contribute novel test results and real world data that are made publicly available. The results of former studies addressing condition monitoring tasks using dictionary learning indicate that unsupervised feature learning is useful for diagnosis and anomaly detection purposes. However, these studies are based on small sets of labeled data from test rigs operating under controlled conditions that focus on classification tasks, which are useful for quantitative method comparisons but gives little insight into how useful these approaches are in practice. In this study, dictionaries are learned from gearbox vibrations in six different turbines, and the dictionaries are subsequently propagated over a few years of monitoring data when faults are known to occur. We perform the experiment using two different sparse coding algorithms to investigate if the algorithm selected affects the features of abnormal conditions. We calculate the dictionary distance between the initial and propagated dictionaries and find the time periods of abnormal dictionary adaptation starting six months before a drivetrain bearing replacement and one year before the resulting gearbox replacement.

Assessing the building envelope performance during occupancy

In order to achieve carbon neutrality in the building field as expected by the Energy Performance of Buildings Directive, it is important to not only be able to calculate energy performance during design but also to be able to measure the actual energy performance of buildings during occupancy. However, there is currently no approved methodology for assessing the energy performance of the building envelope of an occupied building independently of its occupants, its systems and the climate. We applied a mathematical method to determine the heat loss coefficient (HLC) of the building envelope, from data collected in occupied buildings. The paper describes the in-situ measurement protocol and the mathematical models that contributes to address this challenge. Our methodology is demonstrated on a new semi-detached house, more insulated than the regulatory level, located in Brussels from a full year of monitoring data. For this case study, the results are promising. Indeed, some mathematical models show results of the same range value for the occupied insitu HLC and the reference HLC, obtained from in-situ measurements but without occupancy. However, more case studies should be evaluated, in order to validate the methodology.

Spatiotemporal characterization and regional contributions of O3 and NO2: An investigation of two years of monitoring data in Henan, China

To investigate the characteristics of ground level ozone (O3) for Henan Province, the ambient air quality monitoring data of 2015 and 2016 were analyzed. The result showed that the 8 h-max-O3 concentrations displayed a distinct seasonality, where the maximum and minimum values, averaging 140.41, 54.19 μg/m3, occurred in summer and winter, respectively. There is a significant correlation between meteorological factors and O3 concentration. The Voronoi neighborhood averaging analysis indicated that O3, temperature, and ultraviolet radiation in Henan province were decreased from northwest to southeast, while relative humidity and precipitation displayed the opposite trend. Besides meteorological factors, the chemical processes play an essential role in ozone formation. Reactions of NO, NO2 and O3 form a closed system, and the partitioning point of the OX-component (O3 + NO2) was at 40 and 80 μg/m3 for nitrogen oxide (NOX) in winter and summer, respectively, with NO2 dominating at higher NOx pollution and O3 being the major component at lower levels. The relationship between oxidant (OX = O3+NO2) and NOx concentrations were evaluated to understand the regional and local contribution of OX. It showed that high regional contribution occurred in the spring, whereas the highest local contribution lead to the summer peak of O3 observed in Zhengzhou. This present study reveals important environment impacts from the photochemical process and the meteorological conditions in the region with better understanding on the O3 characterization.

Microseismic events on the Åknes rockslide in Norway located by a back-projection approach

The Aknes rockslide in Western Norway is characterised by a steady movement of a rock mass with an extent of about 1 km2 and a yearly deformation rate in the range of 2 to 4 cm. A seismic network consisting of 8 three-component geophones records tens to hundreds of local and distant seismic events daily. Depending on their character, local seismic events show a variety of waveforms, both with abrupt and emergent onsets. Along with the relatively low frequencies of the waveforms, standard location procedure using arrival time measurements is difficult to apply. Based on the event envelopes, we classify local events and obtain their approximate location by stacking STA/LTA ratios of back-projected waveforms. To suppress the influence of complex surface morphology and related complicated wave propagation, we constrain hypocentres to the surface of the slope and determine only horizontal coordinates. The method was successfully tested by locating two types of ground truth data: calibration shots and a block collapse. The test proved the ability of the method to determine the position of sliding events with an uncertainty of less than 36 m, which allows to distinguish amongst several foci of rockslide activity. Application of the method to 8 years of monitoring data shows continuous seismic activity, which is concentrated in the centre and at the western edge of the monitored area. Most likely, microseismic events recorded by the seismic network originate within the body of the rock slope and are related to its disintegration or potentially to sliding on the detachment fault.

Has strategic planning made a difference to amphibian conservation research in South Africa?

Background: Conservation relies on the strategic use of resources because monies for conservation action are limited, especially in developing countries. South Africa’s Frog Atlas project established a baseline for the country’s amphibian data and threat levels in 2004, and in 2009 a prioritisation exercise developed a strategy for conservation research.Objectives: In this article, we assess this strategy for conservation research.Method: We conducted a quantitative and qualitative assessment of research undertaken since the strategy was developed.Results: The strategy has produced a lasting impact on taxonomy, ecological studies, monitoring and capacity building. Publications in all areas have increased, but particularly in conservation ecology. Other indicators are increases in the numbers of locality records for target taxa, species descriptions and postgraduate degrees with amphibians as the principal topic. We document important milestones for South African amphibian conservation, including the first Biodiversity Management Plan for Species (BMP-S) for Hyperolius pickersgilli, a smart device app that uploads locality data to an open access database, 15 years of monitoring data and new amphibian identification books for adults and children. The Red List Index calculated for South African amphibians shows that the country’s species are becoming more threatened (a 1% reduction in 10 years), but a hindcasting exercise suggests that most of the damage was already done by 1990. We provide a checklist for 131 amphibian species in South Africa, of which 82 species are endemic.Conclusion: A strategy for conservation research was found to greatly augment the focus of research on South African frogs. A new strategy should focus on fewer taxa over meaningful time spans.

Effect of age, haemosporidian infection and body condition on pair composition and reproductive success in Great Tits Parus major

Several factors shape lifetime reproductive success, including genetic background, body condition, environmental conditions and ecological interactions such as parasitism. Adults often show higher reproductive success than their young conspecifics, especially in long‐lived bird species, and this may be explained by the cumulative effects of an increase in reproductive experience and the selection of high‐quality individuals from one year to the next. To test whether this pattern also exists in short‐lived bird species, we used 13 years of monitoring data from two Great Tit Parus major populations. The effects of male and female age on several reproductive parameters were analysed in 419 pairs of Great Tits, while accounting for body condition and infection by haemosporidian parasites. Reproductive success was mainly affected by the age‐class of males. Pairs containing a sub‐adult male fledged one‐third fewer chicks than pairs containing an adult male. The difference was not caused by variation in male fertility but could have been caused by better parental care provided by adult birds. In addition to lower reproductive success, first‐year males also had reduced access to mating compared with adult males, suggesting an avoidance of sub‐adult males by females. Nestling body condition was positively correlated with parental body condition, and the body condition of male and female members of breeding pairs was positively correlated. Finally, the number of fledged chicks was mainly affected by the infection status of males. These results temper our previously published results showing an effect of infection on Great Tit reproduction regardless of their sex. In our previous study, and as in most cases, the status of the partner was not taken into account and we show here that this is essential because it can lead to a biased interpretation of the results.

Characterization and spatial distribution of organic-contaminated sediment derived from historical industrial effluents.

Organic sediment contaminants [polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs), and polycyclic aromatic hydrocarbons (PAHs)] were assessed using secondary monitoring data from a former tidal estuary (Boat Harbour) impacted by historical industrial effluents. Spatiotemporal characterization of PCDD/Fs and PAHs in sediments was conducted to inform a sediment remediation program designed to return this contaminated aquatic site back to a tidal lagoon. Spatiotemporal variations of sediment PCDD/F and PAH concentrations across Boat Harbour and off-site reference locations were assessed using secondary monitoring data collected between 1992 and 2015. Sediment PCDD/F toxic equivalency (TEQ) and PAH concentrations were compared to sediment quality guidelines. Sediment PCDD/F concentrations exceeded the highest effect thresholds posing severe ecological health risks. High sediment PCDD/F concentrations have persisted in Boat Harbour despite implementation of Pulp and Paper Mill Effluent Chlorinated Dioxins and Furans Regulations in 1992. PAH concentrations varied greatly. Five individual PAH compounds frequently exceeded severe effect thresholds, in contrast to total PAHs, which were below severe effect thresholds. Forensic analysis using PAH diagnostic ratios suggests pyrogenic PAHs derived from wood processes or coal combustion were likely sources. Twenty-five years of monitoring data revealed large data gaps in our understanding of sediment characteristics in Boat Harbour. Gaps included spatial (vertical and horizontal) and temporal variations, presenting challenges for remediation to accurately delineate sediment contaminants. Deeper horizons were poorly characterized compared to shallow sediments (0-15 cm). Historical secondary monitoring data showed that spatial coverage across Boat Harbour was inadequate. Due to severe ecological health risks associated with high sediment PCDD/F concentrations, remediation of the entire sediment inventory is recommended. Detailed vertical and horizontal sampling within Boat Harbour, establishment of local baseline concentrations, and additional sampling in down-gradient-receiving environments for a suite of contaminants are required to better characterize sediments prior to remediation.

Landscape and management factors influence the occupancy dynamics of sympatric salamanders in an urban preserve system

Conserving amphibian populations living in urban areas is challenging due to a lack of information about urban amphibian natural history, ecology, and responses to habitat management. To address these knowledge gaps, we used 10 years of monitoring data to investigate patterns of occupancy, detectability, and population turnover for sympatric Ambystoma laterale (Blue-spotted Salamanders) and A. tigrinum (Eastern Tiger Salamanders; hereafter Tiger Salamanders) inhabiting 26 suburban preserves in the third largest metropolitan area in the United States, Chicago. From 2009 to 2018 we conducted 2181 artificial cover object surveys at 158 randomly distributed monitoring points and detected Blue-spotted Salamanders 375 times and Tiger Salamanders 85 times. We constructed dynamic occupancy models and used an information theoretic approach to rank a priori candidate models containing landscape, survey, and management covariates. Blue-spotted Salamander occupancy was more than twice as high as Tiger Salamander occupancy. Detection probability for both species was substantially <1 and was influenced by both survey and landscape covariates. Prescribed fire was an important predictor of colonization for Blue-spotted Salamanders and both species exhibited higher rates of colonization at sites near breeding wetlands. Overall rates of turnover were low for both species. Our results reveal that salamander populations can persist in highly fragmented urban preserve systems. We recommend that urban land managers maintain a mosaic of forests and wetlands and consider the impacts of habitat management on non-target species (such as salamanders).