A river runs through it
On one of our longest standing projects, Earthwatch scientist Dr Josef Krecek has worked for nearly 20 years in the Jizera Mountains, concentrating on the restoration of river headwaters and reservoirs that have been affected by acid rain. Located in North Bohemia in the western Czech Republic, the Jizera Mountains form part of the ‘black triangle', along with the Ore and Giant Mountain ranges on the borders of the Czech Republic, Germany and Poland.
Since the 1980s, the fragile terrestrial and aquatic ecosystems of the headwaters - the drainage basins of the mountain rivers - have suffered long-term deterioration caused by acid deposition from the atmosphere. By 1989, two-thirds of forested headwaters had been damaged, resulting in reduced water quality, death of forest trees and loss of fish from mountain streams. Mountain ecosystems are now recovering as Czech industries attempt to meet EU air pollution targets, which has resulted in decreasing sulphur deposition. Recovery and restoration is a slow process, however, and must involve careful management of watershed areas, as well as the decreased pollution levels.
Aim of the project
The aim of this long running study is to assess exactly how the ecosystem has degraded due to acidification, to monitor any recovery, and aid restoration of headwater catchments and reservoirs. By trying to identify the best strategies for headwater rehabilitation, the project is working out how to accomplish "resource management" for the forests and the materials they provide, and the lakes and rivers that supply freshwater, to guarantee their sustainability for the future.
To achieve this aim, the project follows objectives such as:
- evaluating the environmental effects of reforestation, particularly the impacts on water resource quantity and quality;
- analysing trends in atmospheric pollution;
- analysing climate stresses such as extreme air temperatures, rainstorms and windstorms;
- looking at the effects of climate change on the processes of episodic acidification (for example, with rapid snowmelt or intensive summer rainstorms) and the flora and fauna of reservoirs;
- studying the side-effects of reservoir management.
Around 400 Earthwatch volunteers have helped with the research so far, and they undertake a wide variety of tasks. For those who enjoy hiking, there is the job of collecting rain and fog samples from gauges installed at stream and reservoir sites in the mountains; avid anglers can work with local fishermen to catch, measure and weigh fish, analyse gut content and sample scales, tissue and organs for further analysis; aspiring zoologists can get involved in collecting bottom-dwelling organisms from streams and reservoirs, dividing them into taxonomic groups; and for botanists there is the chance to study herbaceous vegetation and the soil by sampling, drying and weighing. Volunteers are also taught how to use instruments such as the Shigometer to compare visual characteristics of forest stands, or geometric equipment to record canopy density.
A decreasing trend in acid atmospheric deposition has been recorded by Josef Krecek and his fellow scientists in the Jizera Mountains, after the extremely high levels of the late 1980s, and progress in the recovery of mountain waters has been the result. However, they have also uncovered warnings of adverse impacts, including nitrogen deposits causing stagnation, an increasing acid load under restored spruce plantations and difficulties in the upper plains for reintroduction of deciduous tree species.
Since 2001, the sulphur load in the ecosystem (causing the acidity) has generally been relatively stable, but nitrogen load is increasing. However, under the forest canopy it is a different story, as deposition of sulphur has increased. In 2008, the average annual concentrations of the gases sulphur dioxide and nitrogen oxide in the air were at safe limits for the environment. But, within spruce plantations, the levels of hydrogen ,which indicate acidity level in soils, still exceed critical limits, at or above which exposure causes harmful effects on sensitive elements of the environment.
Ageing Norway spruce (Picea abies) and Common beech (Fagus sylvatica) trees using tree-ring dating, with records dating from 1821 to 2007, have provided evidence that a significant drop in growth occurred during the acid loading of 1980-1990, but evidence of recovery could be seen from 1995. Although it is not yet known why, spruce trees have been more sensitive to acid pollution than beech.
In the basin of Jizerka (a small settlement in the mountains), the vegetation has changed since the clear-cutting of spruce plantations damaged by acid rain in 1984-1990. Now the soft rush species Junco effuses and a tall invasive grass species called Calamagrostietum villosae, dominate the plant community. This new community has complicated reforestation efforts, with high moisture and high mortality of spruce seedlings hindering tree growth. However, a slow advance in the recovery of the ecosystem was demonstrated in 2008, when the scientists recorded an increase in tree canopy density of 27%, and height of trees by 2.6m.
In studies of the aquatic ecosystem, the scientists have discovered stagnation in some surface waters, and worrying levels of pH, alkalinity, sulphate and aluminium. However, there is positive news because the level of toxic inorganic aluminium has dropped to below the critical value for survival of fish. Native fish became extinct in the waters of the upper plateau in the 1950s, but in the 1990s the project successfully introduced brook trout (Salvelinus fontinalis) into three reservoirs. Stable, self-reproducing populations have now become established in all three reservoirs, although they are still endangered by episodes of acidification which cause elevated, and potentially harmful concentrations of toxic aluminium. The restoration and maintained presence of this ecologically significant species is a huge success, and although experimental reintroductions of brown trout and minnow in the same reservoirs have so far failed, in areas with less acidic waters brown trout are present and thriving over brook trout.
In experiments attempting to decrease the acidity of the Sous reservoir, the scientists carried out liming after the snowmelt in 2008. This was successful, and afterwards the pH did not fall below neutral for the whole summer period. Monitoring of zooplankton, phytoplankton and fish in the reservoir has now begun, and an increase in fish size has already been observed. Liming could also have positive benefits when treating the water for drinking, and an analysis of the cost versus the benefits of this management strategy is now being conducted.
Turning results into actions
This project provides numerous benefits to the local community, such as improving their environment and water resource quality, and restocking the fish in upper streams. The Watershed Authority of the Elbe River is informed of project results to help with water resource control, and the scientists continue to run sessions for cross-sector debate on restoration of lakes and watersheds in the Jizera Mountains. These began in 1997 in cooperation with the Food and Agricultural Organisation of the United Nations. The project results are also being used in the preparation of "Guidelines on Revitalization in Headwater Catchments of Central Europe", which will be a key document for water resources in this area.
The end of the 2009 season will generate even more results to add to these already impressive outcomes, and 2010 will be a milestone twentieth anniversary year for this Earthwatch project.
Find out more about joining the Mountain Waters of the Czech Republic project in its 20th year.
Report by Debbie Winton.