Decades Of Monitoring Research Articles

Fall Quail Densities on Public Lands in Missouri: A Decade of Monitoring

Northern bobwhite (Colinus virginianus) fall population density has been determined annually since 2005 on 19 public land areas managed by the Missouri Department of Conservation (MDC). These demonstration areas, known as Quail Emphasis Areas (QEAs), were created as part of the MDC Strategic Guidance for Northern Bobwhite Recovery: 2003-2013. Management of QEA bobwhite populations, habitat and hunting has been evaluated periodically at the area, regional and statewide scale, and the program has been perpetuated in an updated 2014-2024 Strategic Guidance. QEAs were selected to represent MDC administrative regions and are highly variable in many aspects, e.g., size range from 298 to 3,642 hectares. QEAs are managed adaptively, maximizing usable space and early-successional plant communities, with bobwhite population density and distribution, and hunting, as response variables. Fall bobwhite calling coveys are measured with point transect surveys, distributed to cover nearly 100% of each QE, coveys are flushed to estimate covey size, and density is calculated with the Distance program. Observers, mostly permanent staff, initially received rigorous training, and periodic updates. Across QEAs and years, there has been a high amount of variability in weather and habitat management, and subsequently, population responses have been equally variable, as revealed by preliminary analysis for 2005-2010: (1) Number of covey observations on a QEA in a single year ranged from 0 to 178; (2) Encounter rate (i.e., number of coveys/effort) ranged from 0- 5.95; (3) Density in areas where coveys were detected ranged from 0.003 coveys/ha to 0.103 coveys/ha (covey densities not adjusted for calling rate), and from 0.006 to 0.122 coveys/ha (covey densities adjusted for Missouri-specific calling rate); and (4) Some QEAs showed consistent declines in density from 2005-2010, whereas others increased. We discuss lessons learned from this long-term, statewide effort to demonstrate effective quail management based on quantification of population response to prescribed management.

27 years of benthic and coral community dynamics on turbid, highly urbanised reefs off Singapore.

Coral cover on reefs is declining globally due to coastal development, overfishing and climate change. Reefs isolated from direct human influence can recover from natural acute disturbances, but little is known about long term recovery of reefs experiencing chronic human disturbances. Here we investigate responses to acute bleaching disturbances on turbid reefs off Singapore, at two depths over a period of 27 years. Coral cover declined and there were marked changes in coral and benthic community structure during the first decade of monitoring at both depths. At shallower reef crest sites (3–4 m), benthic community structure recovered towards pre-disturbance states within a decade. In contrast, there was a net decline in coral cover and continuing shifts in community structure at deeper reef slope sites (6–7 m). There was no evidence of phase shifts to macroalgal dominance but coral habitats at deeper sites were replaced by unstable substrata such as fine sediments and rubble. The persistence of coral dominance at chronically disturbed shallow sites is likely due to an abundance of coral taxa which are tolerant to environmental stress. In addition, high turbidity may interact antagonistically with other disturbances to reduce the impact of thermal stress and limit macroalgal growth rates.

Three decades of monitoring in the Rio Cordon instrumented basin: Sediment budget and temporal trend of sediment yield

This paper investigates nearly 30years of monitoring of sediment fluxes in an instrumented Alpine basin (Rio Cordon, Italy). The collected bedload and suspended sediment transport data allows sediment dynamics to be analyzed at different time scales, ranging from short- (single event) to long-term (three decades). The Rio Cordon monitoring station has been operating since 1986, continuously recording water discharge, bedload and suspended load. At the flood event scale, a good relationship was found between peak discharges (Qpeak) and sediment load (bedload and suspended load). The inter-annual sediment yields were analyzed, also assessing the contribution of the single floods to the total sediment budget. The annual suspended load ranges from 10 to 2524tyr−1, while the bedload varies from 0 to 1543tyr−1. The higher annual yields were recorded in the years when large floods occurred, highlighting that the sediment budget in the Rio Cordon is strongly controlled by the occurrence of high magnitude events. Investigation of the seasonal suspended load contribution demonstrated that from 1986 to 1993 most fine sediments were transported during the snowmelt/summer seasons, while autumn and snowmelt were the dominant seasons contributing to sediment yield in the periods 1994–2002 and 2003–2014, respectively. The mean annual sediment yield from 1986 to 2014 is equal to 103tkm−2yr−1, and overall, bedload accounts for 21% of the total sediment yield. The ratio between the sediment transport and the effective runoff of the events allowed the temporal trends of transport efficiency to be inferred, highlighting the existence of periods characterized by different sediment availability. In particular, despite no significant changes in the hydrological variables (i.e. rainfall), nearly a decade (1994–2002) with high transport efficiency appears to have occurred after an exceptional event (recurrence interval >100years). This event affected the sediment availability at the basin and channel bed scales, and provided a legacy influencing the sediment dynamics in the basin over the long-term by increasing the transport efficiency for approximately a decade. This work benefits from the long-lasting monitoring program undertaken in the Rio Cordon and is the product of long-term data series. The quasi-unique dataset has provided detailed evidence of sediment dynamics over about three decades in a small Alpine basin, also enabling the effects triggered by an exceptional event to be analyzed.

The UK Environmental Change Network after twenty years of integrated ecosystem assessment: Key findings and future perspectives

The UK Environmental Change Network (ECN), the UK's Long-Term Ecosystem Research (LTER) network, has now been operating for over twenty years. It was established in 1992 as a set of terrestrial sites at which sustained observations relevant to a range of ecological indicators and environmental parameters could be made. An additional ECN freshwater network was launched in 1994. In this paper we provide a brief history of the network, and describe its current structure and role within a complementary wider range of UK environmental monitoring and observation programmes that are either more focussed on specific parameters or habitats, or operate at different temporal and spatial scales. We then provide a review of the other papers within this Special Issue, which exemplifies the broad range of environmental concerns that ECN data and sites are helping to address. These include network-wide summaries of environmental and biological trends over the first two decades of monitoring, more site-specific assessment of the ecological impacts of local pressures resulting from changes in management, biological and ecosystem service indicator development, and the testing of new monitoring technologies. We go on to consider: (i) future directions of network development and adaptation in light of recently emerging environmental concerns, dwindling financial resources and the consequent need for greater efficiency; (ii) the desire for tighter integration with other monitoring and observation programmes both nationally internationally; (iii) opportunities raised by recent technological developments; and (iv) the need to process and make available data more rapidly to increase the capacity of ECN sites as early warning systems. In its first two decades of operation the ECN has accumulated a robust set of baseline data that describe environmental and biological variability across a range of habitats in unprecedented detail. With appropriate, informed development, these should prove invaluable in discerning the causes and consequences of environmental change for decades to come.

Long-term water quality in the lower Seine: Lessons learned over 4 decades of monitoring

The Seine River is a highly artificialised catchment in Europe, comprising both productive agricultural areas and intense industrial and commercial activity. Due to its strategic importance, monitoring programs in the river started as early as the 1970s. The present study compiles and analyses this valuable data set (1970–2014), thoroughly describing the riverine section downstream of Paris and the estuary. We identify long-term trends and shifting patterns in nutrients and oxygen, and pay special attention to the river’s evolution after the year 2000, when the European Water Framework Directive came into force. The study has a manifest management perspective, and the results are discussed on the basis of the environmental quality standards proposed in current environmental regulations. The data show that water quality has improved remarkably over the past two decades, with sharp reductions of ammonium and phosphate and a progressive increase of dissolved oxygen levels. The amelioration is prominent in the estuary, where summer anoxic episodes have nearly disappeared. As a result, these three parameters are nowadays in good or very good condition throughout the year. The successful abatement of point sources contrasts, however, with the low effectiveness of the measures provided for the control of nutrients from diffuse sources. Nitrate concentration has increased by 150% since the early 1980s, and only very recently has the upward trend been reversed. Bold agri-environmental management measures are required if we are to prevent chronic pollution problems and truly restore the good ecological status of rivers.

Validating faecal glucocorticoid metabolite analysis in the Virunga mountain gorilla using a natural biological stressor.

The continued degradation of primate habitat worldwide is forcing many primate populations into small protected forest islands surrounded by high-density human populations. One well-studied example is the critically endangered mountain gorilla (Gorilla beringei beringei). Decades of monitoring and research on Rwanda's mountain gorillas offer a unique opportunity to use non-invasive endocrine analysis to address pressing questions about the conservation of this endangered population. The aims of our study were as follows: (i) to validate field and laboratory methods for assessing stress through faecal glucocorticoid metabolite (FGM) analysis using inter-social unit interactions as a natural stressor; (ii) to determine the excretion lag times between interactions and detectable stress response in faeces; and (iii) to determine whether there are circadian patterns of FGM excretion. We collected ~6000 faecal samples from 127 known gorillas in 10 habituated groups, monitored by the Dian Fossey Gorilla Fund's Karisoke Research Center over 21 months in 2011 and 2012. Extracted FGMs were measured using a cortisol enzyme immunoassay (R4866; C. J. Munro). Results revealed cause–effect relationships between inter-unit interactions and increased FGMs (relative to individual pre-event samples) between 20 and 140 h after interactions, with the peak most often occurring on day 3. There was no evidence of circadian patterns in FGM concentrations, as previously shown in many species with long gut passage times. However, baseline FGM concentrations were lower in adult males than in adult females, and variation was associated with the collection month, indicating possible seasonal variation. This study provides a biologically validated, field-friendly faecal hormone metabolite extraction and laboratory enzyme immunoassay analysis method for non-invasive monitoring of adrenocortical activity in Virunga mountain gorillas. The methods are useful for future evaluation of a variety of environmental and human-induced potential stressors in this critically endangered population.

Identificación de la incertidumbre en el proceso estocástico de caudales medios en el río Fonce (San Gil – Santander)

Con la presente investigación se pretende demostrar que el movimiento del agua del río Fonce interpretado como errático en los valores medios de caudales en la estación hidrológica del IDEAM con sede en San Gil (Santander) es un problema de percepción y realmente su tipificación como proceso estocástico tipo Wiener puede obedecer más a los márgenes de incertidumbre que generan los instrumentos de medición y no tanto a la naturaleza errática del comportamiento del río. Inicialmente se compilaron los datos de los valores medios de caudales del río, posteriormente se consideraron dos casos de desarrollo del trabajo (sin inclusión y con inclusión de la incertidumbre) y con soporte en ello se plantearon los espacios muéstrales, los eventos (para los caudales bajos, medios bajos, medios y altos), las sigmas álgebras, los espacios medibles, los espacios de probabilidad, las variables aleatorias y finalmente el proceso estocástico como tal. Este trabajo permite concluir que el movimiento aparentemente errático en el comportamiento de los caudales medios del río Fonce puede obedecer a los altos niveles de incertidumbre que genera principalmente el molinete en el aforo del río y no tanto a una propiedad intrínseca en la naturaleza del río. Esto conllevará a plantear nuevas interpretaciones estocásticas para modelar la dinámica de los caudales medios del río Fonce, en las cuales se deberán precisar los errores en las mediciones en forma detallada para cada uno de los instrumentos que se utilizan en las mediciones y en cada uno de los aforos a lo largo de las más de tres décadas de monitoreo. Este trabajo es resultado del proyecto de investigación UMNG 1770 de 2015, con auspicio financiero de la Vicerrectoría de Investigaciones de la UMNG y se desarrolló en conjunto con la Universidad de Pamplona.

The Demographic Success of Marsilea Quadrifolia L. in a Man-Made Water Body from Danube Delta Biosphere Reservation

Abstract Marsilea quadrifolia L. (water clover) is a unique species from Romanian flora that belongs to the Marsileaceae family and is one of the most vulnerable plants in Europe due to the loss of its habitats. In this paper, the demographic evolution of a new M. quadrifolia population in the Danube Delta Biosphere Reserve and its natural and anthropic threats are reported. The aquatic fern, M. quadrifolia, has colonized a suitable man-made water body. After a decade of monitoring, the demographic trend is positive but the support capacity of habitat for the water clover remains limited in the long term. The population is vulnerable due to succession of vegetation and its vicinity with a human settlement. The establishment of a micro-reserve represents a suitable method to protect and maintain this threatened M. quadrifolia population.

Earth observation-based coastal zone monitoring of the Yellow River Delta: Dynamics in China's second largest oil producing region over four decades

The largest challenge for the Yellow River Delta region is finding an equilibrium between its two largest assets: large, valuable wetland reserves rich in biodiversity, declared as Ramsar sites in 2013 and breeding and resting grounds for numerous migratory bird species on the one hand, and extensive industrial and urban development based on the wealth of large underground oil and gas reserves, on the other. Based on high and highest spatial resolution satellite imagery covering nearly four decades, we employed manual feature digitization as well as rate-of-change statistics automatically derived with the Digital Shoreline Analyses System (DSAS) and present oil-industry-induced river bed changes and related coastal dynamics manifested via land erosion or accretion, and thus overall changes in the appearance of the Yellow River Delta. Over the past 37 years large re-diversions led to net erosion areas with over 13 km of shoreline retreat, and net accretion areas with over 21 km of shoreline advance. The satellite data furthermore enabled an assessment of oil pump development in the delta for the past two decades, indicating a strong expansion of oil extraction activities even in two of the delta's protected nature reserves, taking place at times and locations that indicate noncompliance with national regulations. Overall, the study proves the power of satellite imagery to quantify changes in the coastal zone, and to detect industry related activities; including the monitoring of compliance to restricting regulations. It is especially the freely accessible Landsat archives, granting four decades of monitoring, which are of immeasurable value to depict the regions dynamics. With Landsat 8 already in orbit and with the upcoming launch of the Sentinel-2 satellite, the monitoring concept presented here can be continued into the future.

Sustaining Seat Belt Use in a High-Use State

Hawaii has been a high-use state for seat belts since 1985. For the past decade, the state has averaged well over 95% overall compliance. Efforts to maintain or even increase this exceptional use rate are challenging. Hawaii has a large tourist population. Nonusers may come from demographic and social groups that are difficult to reach. This paper summarizes two decades of monitoring, research, and evaluation of programs in Hawaii and suggests several aspects of the state's success in promoting seat belt use. A key component involves understanding the geography of seat belt use and the relationships between enforcement activities and public outreach and education. Although it may be difficult or impossible to attain universal use, some directions for further effort in promoting seat belt use in high-use communities are clearly possible. This research will be increasingly important as other communities achieve higher use rates and transition to efforts geared toward sustaining seat belt use. Enforcement is part of an overall program for increasing seat belt use and traffic safety.

A multivariate assessment of the trophic state of a man-made reservoir in North Tunisia

AbstractIn the present work, we attempt to test the applicability of common trophic state indices such as Carlson’s index (1977), probability distribution diagrams of Vollenweider (1982), and fixed boundary systems of the OECD (1982) and of Nurnberg (1996) for evaluating the risk of eutrophication in the Sejnane reservoir in North Tunisia. The environmental parameters considered include monthly values of nutrients, chlorophyll a, Secchi transparency, turbidity and dissolved oxygen over a decade of monitoring from November 2001 through October 2011. To compile data and to identify key aspects of water quality, a multivariate technique as Principal Component Analysis was performed. Results show that productivity is limited by sedimentary turbidity, which contributes to decreasing water clarity and promotes the adsorption of phosphorus to suspended matter that decreases, indirectly, the bioavailability of nutrients. The Nurnberg model provides an accurate assessment of eutrophication with a clear internal coherence between self-indicators, and appears to be the most suitable way to evaluate eutrophication risk in the reservoir.

A decade of monitoring on Pool 26 of the upper Mississippi River System

We present information gleaned from 10 years of data collected by the water quality component of the Upper Mississippi River Restoration Environmental Management Program’s Long Term Resource Monitoring Program (LTRMP) from Pool 26 of the Upper Mississippi River System (UMRS). The Pool 26 reach of the UMRS includes the confluence with the Illinois River, and the confluence with the Missouri River just downstream of Mel Price Locks and Dam. The surrounding communities in both Illinois and Missouri benefit greatly from the natural resources provided by these rivers. We estimate that annual expenditures are 55 million for fishing and hunting, respectively, in the region surrounding Pool 26 based on license sales and state expenditure data from the U.S. Fish and Wildlife Service. Additionally, there is a commercial fishery active in Pool 26, recreational boating, and the UMRS provides drinking water for many municipalities in this region. Finally, the Upper Mississippi River System is a major transportation system, and Pool 26 receives the greatest amount of barge traffic for any river reach in the UMRS. The LTRMP began collecting data in 1988, but the first years of the program were experimental. Currently followed monitoring protocols for water quality and fish monitoring were adopted in 1993; however, a major flood event in that year prevented full data collection for that year. Data from the LTRMP water quality component demonstrate that Pool 26 is a highly productive river reach. Long-term averages of chorophyll-a, total phosphorous, total nitrogen, and total inorganic solids are comparable to levels in eutrophic to highly eutrophic lakes. The average current velocity in the main channel of the Mississippi River in Pool 26 ranges from 0.364–0.414 m/sec. during the summer and fall. Even during the lowest discharge levels in a year, the reach has a residence time no longer than 2.7 days. Discharge was significantly related to many water quality parameters, including Secchi depth, turbidity, total suspended solids, total nitrogen, nitrate-nitrite, and total phosphorus. We observed a significant linear increase in mean water temperature in the main channel from 1994 to 2004. When these data were analyzed by season, positive linear trends were found during the spring (0.515°C per year) and fall (0.646°C per year). Continued monitoring is necessary to determine if these observations represent short term fluctuations or long-term trends and to detect any related effects on this river reach.

Trends in Deforestation and Forest Degradation after a Decade of Monitoring in the Monarch Butterfly Biosphere Reserve in Mexico

We used aerial photographs, satellite images, and field surveys to monitor forest cover in the core zones of the Monarch Butterfly Biosphere Reserve in Mexico from 2001 to 2012. We used our data to assess the effectiveness of conservation actions that involved local, state, and federal authorities and community members (e.g., local landowners and private and civil organizations) in one of the world’s most iconic protected areas. From 2001 through 2012, 1254 ha were deforested (i.e., cleared areas had <10% canopy cover), 925 ha were degraded (i.e., areas for which canopy forest decreased), and 122 ha were affected by climatic conditions. Of the total 2179 ha of affected area, 2057 ha were affected by illegal logging: 1503 ha by large-scale logging and 554 ha by small-scale logging. Mexican authorities effectively enforced efforts to protect the monarch reserve, particularly from 2007 to 2012. Those efforts, together with the decade-long financial support from Mexican and international philanthropists and businesses to create local alternative-income generation and employment, resulted in the decrease of large-scale illegal logging from 731 ha affected in 2005–2007 to none affected in 2012, although small-scale logging is of growing concern. However, dire regional social and economic problems remain, and they must be addressed to ensure the reserve’s long-term conservation. The monarch butterfly (Danaus plexippus) overwintering colonies in Mexico—which engage in one of the longest known insect migrations—are threatened by deforestation, and a multistakeholder, regional, sustainable-development strategy is needed to protect the reserve.

Arctic shorebirds in North America: a decade of monitoring

Foreword Susan K. Skagen, Paul A. Smith, Brad Andres, Garry Donaldson and Stephen Brown Part 1: Introduction 1. GOALS AND OBJECTIVES Victoria Johnston and Jonathan Bart 2. METHODS Jonathan Bart, Victoria Johnston, Paul A. Smith, Ann Manning, Jennie Rausch and Stephen Brown Part 2: Regional Reports 3. SHOREBIRD SURVEYS IN WESTERN ALASKA Brian J. McCaffery, Jonathan Bart, Catherine Wightman and David Krueper 4. NORTH SLOPE OF ALASKA Jonathan Bart, Stephen Brown, Brad Andres, Robert Platte and Ann Manning 5. YUKON NORTH SLOPE AND MACKENZIE DELTA Jennie Rausch and Victoria Johnston 6. SOUTHAMPTON AND COATS ISLANDS Paul A. Smith, Victoria Johnston and Jennie Rausch 7. PRINCE CHARLES, AIR FORCE, AND BAFFIN ISLANDS Victoria Johnston and Paul A. Smith 8. SMALL-SCALE AND RECONNAISSANCE SURVEYS Jonathan Bart, Brad A. Andres, Kyle Elliott, Charles M. Francis, Victoria Johnston, R.I.G. Morrison, Elin P. Pierce and Jennie Rausch Part 3: Methodology 9. AERIAL SURVEYS: A WORTHWHILE ADD-ON TO PRISM SURVEYS, ESPECIALLY IN THE INTERIOR? Kyle H. Elliott and Paul A. Smith 10. SURVEY METHODS FOR WHIMBREL Lisa Pirie and Victoria Johnston 11. TIER 2 SURVEYS Lisa Pirie, Victoria Johnston and Paul A. Smith 12. ARCTIC PRISM TIER 3 - PROGRESS NOTES FROM THE NORTHWEST TERRITORIES-NUNAVUT BIRD CHECKLIST SURVEY Lindsay A. Armer, Craig S. Machtans and Brian T. Collins 13. DESIGN OF FUTURE SURVEYS Jonathan Bart and Paul A. Smith Part 4: Synthesis 14. SUMMARY Jonathan Bart and Paul A. Smith 15. PRIORITIES FOR FUTURE PRISM SURVEYS Jonathan Bart, Victoria Johnston, Jennie Rausch, Paul A. Smith and Brian McCaffery 16. LITERATURE CITED Appendices A. OTHER METHODS FOR ESTIMATING TRENDS OF ARCTIC BIRDS Jonathan Bart, Stephen Brown, R. I. Guy Morrison and Paul A. Smith B. REGIONAL DENSITY ESTIMATES C. COMMON, SCIENTIFIC AND ABBREVIATED NAMES FOR SPECIES INCLUDED IN THE VOLUME Index

Arctic Shorebirds in North America: A Decade of Monitoring, edited by Jonathan Bart and Victoria Johnston

Arctic Shorebirds in North America: A Decade of Monitoring, edited by Jonathan Bart and Victoria Johnston

An Exceptional Radio Flare in Markarian 421

In September 2012, the high-synchrotron-peaked (HSP) blazar Markarian 421 underwent a rapid wideband radio flare, reaching nearly twice the brightest level observed in the centimeter band in over three decades of monitoring. In response to this event we carried out a five epoch centimeter- to millimeter-band multifrequency Very Long Baseline Array (VLBA) campaign to investigate the aftermath of this emission event. Rapid radio variations are unprecedented in this object and are surprising in an HSP BL Lac object. In this flare, the 15 GHz flux density increased with an exponential doubling time of about 9 days, then faded to its prior level at a similar rate. This is comparable with the fastest large-amplitude centimeter-band radio variability observed in any blazar. Similar flux density increases were detected up to millimeter bands. This radio flare followed about two months after a similarly unprecedented GeV gamma-ray flare (reaching a daily E>100 MeV flux of (1.2 +/- 0.7)x10^(-6) ph cm^(-2) s^(-1)) reported by the Fermi Large Area Telescope (LAT) collaboration, with a simultaneous tentative TeV detection by ARGO-YBJ. A cross-correlation analysis of long-term 15 GHz and LAT gamma-ray light curves finds a statistically significant correlation with the radio lagging ~40 days behind, suggesting that the gamma-ray emission originates upstream of the radio emission. Preliminary results from our VLBA observations show brightening in the unresolved core region and no evidence for apparent superluminal motions or substantial flux variations downstream.

Length-weight relationships of 40 freshwater fish species from two decades of monitoring in Flanders (Belgium)

Summary Nearly 263 000 individual length–weight (L/W) data, collected during 2839 fish stock assessments between 1992 and 2009, were used to calculate L/W relationships (W = aLb) of 40 freshwater fish species from Flanders (Belgium). Roach Rutilus rutilus, perch Perca fluviatilis, three-spine stickleback Gasterosteus aculeatus, gudgeon Gobio gobio and European eel Anguilla anguilla were the most abundant species in our surveys. Mean a and b values were in accordance with those available in FishBase. Mean b across all examined species is 3.094 (95% CL = 3.041 to 3.148) indicating a tendency towards slightly positive allometric growth in most fishes (thirty-three species with b > 3). On the basis of a form factor equation, we characterized 2 species as ‘eel-like’, 7 as ‘elongated’, 22 as ‘fusiform’ and 9 species as ‘short and deep’. This paper adds a substantial dataset to the yet scarcely available a and b values of European populations of freshwater fish species.

Twenty Years of New Zealand’s National Rivers Water Quality Network: Benefits of Careful Design and Consistent Operation1

Davies-Colley, Robert J., David G. Smith, Robert C. Ward, Graham G. Bryers, Graham B. McBride, John M. Quinn, and Mike R. Scarsbrook, 2011. Twenty Years of New Zealand’s National Rivers Water Quality Network: Benefits of Careful Design and Consistent Operation. Journal of the American Water Resources Association (JAWRA) 47(4):750-771. DOI: 10.1111/j.1752-1688.2011.00554.x Abstract: This paper reviews New Zealand’s National Rivers Water Quality Network (NRWQN), which is now in its third decade of monitoring. The NRWQN is noteworthy for being operationally stable throughout its history, and the resulting consistency is increasingly valuable for detecting water quality trends and for “anchoring” temporary special purpose monitoring campaigns. The NRWQN was carefully designed following considerable effort to learn from monitoring experiences elsewhere. Monthly visits are made to 77 sites (all near hydrometric stations) on 35 river systems that cumulatively drain about one half of the national landscape. “Core” (routinely measured) variables are: conductivity, pH, temperature, dissolved oxygen, visual clarity, turbidity, colored dissolved organic matter, fecal indicator bacteria, and different forms of nitrogen and phosphorus (italics indicate field measurements). Associated benthic biological monitoring comprises monthly visual assessment of periphyton and annual sampling for macro-invertebrates. We overview the conception, design, initiation, and operational history of the NRWQN, and highlight the diverse applications of its datasets including numerous scientific applications, national-scale modeling of material fluxes, and state-of-environment reporting and practical water management at both regional and national scale. The qualified success of the NRWQN can probably be attributed to careful (and parsimonious) design and consistent operation.

A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?

Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.

The Sibyla model and development of beech forests affected by air pollution

AbstractThe paper deals with the health status, production and structure of autochthonous beech stands in the eastern part of the Krkonoše Mts. (Czech Republic). The region was affected by increased air pollution load due to long-range SO2 transmission from the late 1970s to the early 1990s. In 1980, five research plots were established in long unmanaged beech stands at an optimum stage. Tree coordinates and initial biometrical measurements were made in 1980 and repeated in 2005. The defoliation of individual trees was monitored every year (ICP Forests principles). The actual stand development is compared with the model development worked out by the Sibyla growth simulator in variants with a model of natural mortality and with entering a real mortality of trees. Differences between the stand characteristics of actual and simulated development of forest stands suggest some production losses. The reason to the losses can be seen in the long-term impact of air pollution in the first decade of monitoring and its after-effects on soil quality and worsening health condition of stands. The anticipated acceleration in the onset of the phase of stand disintegration under the influence of air pollution load was not demonstrated.