Not all rivers and streams plot a constant course towards the sea. Some naturally dry up when there is little rain, leaving behind a dry stream bed which floods the next time there is a heavy storm. In fact, most river systems have areas where at least some of the river bed will dry up, usually for days, sometimes for months or years.
For example, at least half of the 2700km long Tagliamento River in Italy is temporary (according to this journal article). At the other end of the world in a far colder climate, most of the streams formed from melting ice on Antarctica last only for a few months every year. Other rivers and streams around the world have become temporary due to the fragmentation of water flows through dam and weir construction, or through the removal of water for crop irrigation and industry. It is thought that changes to rainfall and air temperatures in future climates will cause even more rivers to become temporary, especially in arid regions.
A new journal article in Science by Vicenç Acuña and colleagues including BioFresh leader Klement Tockner argues whilst temporary rivers and streams are extremely important, both ecologically and culturally, they are not adequately managed and protected by current environmental policy.
Dry river beds create surprisingly diverse ecosystems
Despite their barren appearance, dry river beds can be very important ecologically. They can support a unique set of plants and animals that are adapted to huge fluctuations in water availability (what ecologists term ‘wet’ and ‘dry’ phases), and massive disturbances when high rainfall floods a dry channel. The dropping of nutrient and mineral rich silt by receding waters (often termed ‘deposition’) often creates fertile strips of land for vegetation to grow, even in a desert, and so can provide unusually diverse habitat for many mammals, birds and insects, even when there is no water flow.
Similarly, dry river beds can act as egg and seed banks for many aquatic insects and plants which lie dormant in dry periods, then hatch or germinate when water returns. Dry river beds can also provide important migration corridors through the landscape for some animals, often guiding the way to where there may be temporary waterholes.
Connecting the wider environment
Temporary rivers and streams are important providing in what ecologists term ‘connectivity’, in the way they connect different ecological communities and flows of water, energy and nutrients across the wider landscape. A river channel that appears to be dry may still have water flowing underneath the surface, connecting more permanent flows elsewhere. Temporary rivers remind us that a river ecosystem is not only made up of the water you can see flowing on the surface, but of the often invisible flows and interactions of underground water, nutrients, plants and animals.
The importance of flux and change
Temporary rivers are an example of an ecosystem in constant flux, regularly altered by environmental change and disturbance. A key point here – especially when considering the work of the MARS project – is that intermittent and sometimes unpredictable water flows should not be seen as an unnatural stress on the ecosystem. Instead, these changing flows are an important part of these distinctive environments, shaping a unique habitat for a number of different plants and animals.
As a result, temporary rivers are increasingly studied by ecologists (e.g. Larned et al, 2010), the results of which will help work out how best to manage and conserve these fluctuating ecosystems. This research is particularly important given predictions of changing climates where some areas of the world become more arid and dry and others become wetter and more flood prone.
Dry river beds as spaces for human subsistence, storytelling and culture
Dry river beds are important to humans, too, providing migration routes and fertile places for animal grazing and agriculture. In the Dreamtime stories of Australian Aborigines, dry river beds were formed when a giant frog named Tiddalik drank all the rivers dry. The story of Tiddalik has been compared to that of the water-holding frog, which burrows underground during dry periods, reemerging during heavy rainfall to feed, breed and take on water in special skin pockets. When in search of water in dry periods, one Aboriginal trick is to dig up water-holding frogs from dry riverbeds in the Outback and give the animals a gentle squeeze, which releases water from the frog’s skin – a bit like a natural water bottle.
In Botswana, there are similar unexpected natural riches to be found beneath the partially dry Okavango delta. Local people ‘fish’ for catfish which lie dormant for weeks on end beneath dry river beds – a process known by biologists as aestivation. As seasonal flood waters shrink on the delta in the autumn, shoals of catfish rampage up shrinking stream channels to breed and feast on small prey fish trapped by the receding water. This ‘catfish run’ is a well-known phenomenon to locals and tourists alike, and people gather to see shoals of catfish turn the shrinking streams into boiling brown masses of water as they feed.
When is a river not a river? Challenges for managing temporary waterways
So, temporary rivers are important to humans as well as to plants and animals. But how can we best manage and protect rivers that are not always there? As the new paper by Acuña et al states, “widespread degradation [of temporary rivers] stems from lack of recognition, poor understanding, and inadequate management”.
For example, as this paper by Alisha Steward and colleagues points out, seasonally dry riverbeds have been completely covered up by roads in many cities, such as Las Ramblas in Barcelona. Other temporary rivers have been inundated by water from dams or wastewater from industry, completely changing their natural flow regimes and encouraging the growth of populations of invasive species.
This lack of visibility for temporary rivers is also evident in global environmental policy. As Acuña et al outline: “The legal status of intermittently flowing streams and rivers and the extent to which they are incorporated into policy, management, and regulatory decisions vary widely depending on how temporary waters are defined by the authorities, as well as what kinds of protection are given to temporary waterways. Even where flow intermittency is prevalent, temporary waterways may not be legally recognised as part of the river network.”
Examples of current management from the EU, United States and Australia
Definitions are a key challenge here: if you can define what needs managing, then it makes that task a lot easier. For example, in the European Union, a temporary stream or river may not be protected under the Water Framework Directive, depending on the different ‘typology’ systems that different areas of Europe use to classify their waterways. As the Acuña et al paper describes, this means that protection for temporary waterways in Europe is patchy and insufficient.
In the United States, rivers and streams which flow year round are given ‘jurisdictional’ legal protection against pollution and alteration. The definition, and need for protection, of temporary streams is considered on a case-by-case basis, meaning that many are not protected under this same jurisdictional basis. In contrast, in Australia temporary waterways are managed as part of wider river management plans in most areas, perhaps as a result of the wider awareness of these intermittent flows in Australian culture.
Recommendations for better management and protection of temporary rivers and streams
Broadly, it’s the inconsistency in definition, awareness and management of temporary rivers and streams that is key here. As Acuña et al argue, for environmental policy to be consistent with the current state of science, temporary waterways should be legally defined and managed as part of the river network they connect to – however irregularly. Even if flows are so rare that the river channel is usually dry, the authors argue that this definition as part of the wider system should still apply where the dry channels are important habitats for plants and animals.
How would stronger policies for managing and protecting temporary waterways be put into practice? Acuña et al state that an important step is to better map temporary rivers and streams, their flows and their biodiversity. The ecology of temporary streams will need to be monitored using biological indicator systems to understand the diversity of life they support, and how populations of plants and animals change in response to different water levels.
The intermittency of flow in these ecosystems isn’t a negative ecological stress, instead an important factor in shaping the form and diversity of these unique environments. How environmental policy can respond to such variation in flow and ecology of temporary rivers, particularly under future climate change, is an important challenge for global water management. In this context, the Acuña et al paper is important in bringing together the growing set of available research, and publishing these clear recommendations in such a high-profile journal.
Reference: Acuña et al (2014) ‘Why Should We Care About Temporary Waterways?’ Science, 343, 1080-1081
Last week, we wrote about a new European Court of Auditors report which suggested that sustainable water management goals could be better integrated into the Common Agricultural Policy. A recent joint BioFresh / REFRESH science policy brief discusses a similar topic: how riparian ‘buffer zones’ along waterways can help boost freshwater biodiversity conservation and restoration efforts in agricultural land, both now and in the future.
The policy brief outlines how restoring woodland, grassland and reedbeds in riparian areas – the strips of non-agricultural land that run alongside rivers – can help prevent fluctuations in water temperature, provide a range of wildlife habitat, stabilise river banks, help regulate flooding, and filter agricultural pollution and debris before it reaches the river. As a significant proportion of Europe’s waterways lie in agricultural land, the process of conserving and restoring riparian buffer zones has the potential to improve the health and diversity of many of the continent’s freshwaters.
In particular, the brief outlines how woodland buffer zones may have an important role to play in mitigating the effects of potential climate warming on freshwater ecosystems by shading and cooling the water surface. This topic was investigated by Peter Brinkmann Kristensen and colleagues from Aarhus University in a 2013 journal article, and reported in a January 2014 REFRESH policy brief.
As a result, the joint BioFresh / REFRESH brief – published in April 2014 following the ‘Water Lives’ symposium – suggests that creating and restoring such riparian zones in agricultural land could strengthen adaptive planning for future climate change within the Water Framework Directive and potentially help bring freshwater conservation into the Common Agricultural Policy.
Keeping Rivers Cool
Understanding the role of riparian zones and other agri-environment schemes on freshwater ecosystems is a widely researched topic at present. In Lancashire in North West England, the Ribble Rivers Trust are running a project called ‘Keep Rivers Cool‘ in conjunction with the Environment Agency. At present, over 40,000 trees have been planted in riparian zones across the Ribble catchment, intended to shade and diversify the water’s edge and mitigate the effect of projected temperature increases on the river’s ecosystems. Prolonged increases in water temperatures reduces the amount of oxygen in the water, which can result in widespread fish deaths.
Water Friendly Farming
Another collaborative UK research project ‘Water Friendly Farming’ involving the Freshwater Habitats Trust, the Game & Wildlife Conservation Trust, University of York and agrochemical company Syngenta has established a catchment-scale study of 25 farms across 30 km² of farmland in Leicestershire.
The study seeks to understand how different agri-environment schemes – such as riparian buffer zones, different soil and nutrient management schemes and bankside fencing to restrict livestock access – influence freshwater biodiversity and ecosystem services at the catchment scale. There are further details on this scheme in a leaflet here (pdf), and we’ll publish an interview with Jeremy Biggs from the Freshwater Habitats Trust at the end of the month.
A recent European report suggests that attempts to promote freshwater ecosystem conservation in European agricultural policy have so far proved largely unsuccessful. The report, published in May 2014 by the European Court of Auditors (pdf), describes how priorities for freshwater ecosystem conservation outlined in the Water Framework Directive (WFD) have yet to be successfully integrated into the Common Agricultural Policy (CAP).
The Common Agricultural Policy and the Water Framework Directive are two key European policies shaping the form and function of the continent’s environment. Formed in 2000, the WFD requires countries to achieve ‘good status‘ for surface and groundwater by 2015 through a set of River Basin Management Plans (RBMPs).
The ‘status’ of water is assessed using four measures: biological (e.g. biodiversity); hydromorphological (e.g. river bank structure); physical-chemical (e.g. temperature and nutrient levels); and chemical (e.g. water pollutants). According to a 2012 European Environment Agency report, it is ‘not likely’ that Europe’s water will reach the goals set out by the WFD in 2015, in either water quality (e.g. owing to pollution) or quantity (e.g. owing to abstraction).
Agriculture is a key source of environmental stress on freshwaters. In Europe, it accounts for around 33% of total water use (e.g. for irrigation) and is the main source of nutrient pollution in water. Agricultural land surrounds many lakes and rivers and significantly influences the quality and quantity of water that reaches them. As a result, there are increasing calls across the continent to devise ways that agriculture can become more ‘water friendly’.
Introduced in 1962, the Common Agricultural Policy is the main policy influence on Europe’s agricultural land. There have been repeated calls by the Council of the European Union to better protect freshwaters from agricultural water pollution and abstraction through CAP as a means of helping reach the water management goals of the WFD. This cross-policy process has been put into action through two policy instruments: cross-compliance and rural development.
Cross-compliance is a CAP mechanism which ties direct payments to farmers to compliance with a set of rules based on maintaining agricultural land in good environmental condition. Examples include reducing the use of sewage sludge on farmland, and promoting buffer strips of vegetation at the edge of rivers and lakes. Non-compliance with these rules can lead to reduced CAP payments to farmers.
Rural development is shorthand for the European Agricultural Fund for Rural Development (EAFRD), which provides financial incentives for farmers voluntarily going beyond the requirements of legislation to promote biodiversity conservation on their land. Such voluntary actions might include wetland restoration, reduced pesticide use, the ‘naturalisation’ of drains and ditches or more extensive grazing regimes.
The European Court Audit, carried out between 2012-13, involved visits to catchments in seven European countries, an online survey of 140 farm advisory boards, and consultation with agricultural organisations, EC departments and the European Environment Agency. It concluded that cross-compliance and rural development mechanisms have only been ‘partially successful’ in bringing the concerns of European water policy into CAP.
A key point here is that CAP has the potential to provide significant financial incentives to farmers to sustainably manage water through these mechanisms. CAP accounts for around 40% of the total EU budget (€58.1 billion in 2012) – a significant amount of funding, which if these mechanisms proved successful could significantly help strengthen the goals of the unfunded WFD.
So why have the European Court of Auditors concluded that cross-compliance and rural development mechanisms in CAP have only been ‘partially successful’ in promoting freshwater ecosystem conservation on agricultural land?
First, it is argued that delays in the implementation of the WFD in Europe have held up its integration into CAP. Second, cross-compliance mechanisms currently have key weaknesses in protecting freshwaters. Most importantly, they do not currently include regulations on the use of phosphorous (which can cause algal blooms) and pesticide use in assessing environmentally friendly farming, and there is only a partial implementation of the scheme at farm level.
Third, requirements for cross-compliance vary widely between European countries, particularly in the requirements for riparian buffer strips and use of water in irrigation. Fourth, the potential of the rural development fund to reward farmers for voluntary environmental conservation is underused with regards to water, with water-related problems relating to agriculture not comprehensively identified and integrated into the scheme.
Fifth, the ‘polluter pays‘ principle doesn’t exist in the CAP payment scheme, meaning that penalties for polluting, administered through reduced cross-compliance payments, may not equal the cost of cleaning up the polluted habitat. Sixth, it is argued that monitoring networks for the effect of agriculture on freshwater ecosystems across Europe are incomplete and fragmented, and therefore agri-environment evaluation schemes under CAP are of limited value.
In short, there are numerous ways that water-related problems in Europe could be better brought into existing mechanisms within CAP to help promote the goals of the WFD and work towards healthy freshwater ecosystems.
The Audit therefore gives three key recommendations. First, the existing cross-compliance and rural development mechanisms should be altered to better promote sustainable water use (e.g. by incorporating phosphorous and pesticides into cross-compliance).
Second, it recommends that the process of implementing the WFD across Europe is speeded up for the next management cycle (which begins in 2015) to give clear, concrete goals for the CAP mechanisms to follow.
Third, it is suggested that monitoring systems for understanding and evaluating the links between agricultural practices and water quality and quantity are improved across Europe to help target areas where CAP funds are most needed.
Finding ways to make agriculture more ‘water friendly’ is a key challenge for freshwater conservation. We’ll publish more posts over the coming weeks on the theme, profiling schemes such as the collaborative ‘Water Friendly Farming‘ project in the UK, which looks to understand the effect of different agricultural practices on our freshwaters.
The designation and management of protected areas has been a cornerstone of biodiversity policy for more than a century. In the 1970s, for example, the international community agreed to expand the global protected reserve area system guided by the representation principle – the idea that populations of all species, as well as examples of all habitats, should be represented within regional and national protected area networks and reserve boundaries . They set a goal of 10% of the Earth’s land area to be protected, which has since increased to 17% under Aichi target 11.
Delivery of the representation principle has historically been constrained by gaps in biodiversity knowledge: for instance most reserve systems have been designed without reference to freshwater biodiversity simply because information on the distribution and status of freshwater biodiversity was unavailable.
Identifying the Key Freshwater Biodiversity Areas visualized on this map involved the production of distribution GIS shape files for every species of amphibian, fish, crab, dragonfly and freshwater plant in Africa. This hugely impressive undertaking of the IUCN Freshwater Biodiversity Unit was completed under the BioFresh project. The goal of KBAs is to improve place-based conservation of freshwater biodiversity. However it is the underlying KBA datasets as much as the mapped output that translates KBAs into action on-the-ground.
A good case in point is the Program to Reinforce the Protected Area Network (PARAP) in the Democratic Republic of the Congo (DRC). This is being implemented by the Institut Congolais pour la Conservation de la Nature (ICCN) and the World Wide Fund for Nature (WWF) and funded by the German Federal Ministry of Environment, Nature Conservation and Nuclear Safety (BMU) to support the DRC’s commitment to expand their reserve network to 17% of their national land a
According to Michele Thieme, Senior Freshwater Scientist with WWF the goal of PARAP was to revisit the DRC protected area system – “to go to existing protected areas and see what was still their and what threats they faced and then to redesign and expand reserve system. Part of this was to bring in the freshwater biodiversity dimension using MARXAN.”
MARXAN is a decision support software tool that deploys algorithms to generate reserve system design that achieve specified biodiversity representation goals in an optimal way. The MARXAN tool requires setting targets in the algorithms that process the habitat and species data. It then runs through multiple interactions and “spits out” the best solution and alternative scenarios based on the selection of different planning units.
Thieme started with a meeting of scientists and DRC government representatives with expertise in freshwater who set the conservation targets. These included the percentage of freshwater ecosystem types and species distribution to be represented in the reserve system along with the spatial scale of potential reserves. Next she described how they entered into the MARXAN software shape files of different ecosystems types that WWF had previously developed along with newly available IUCN KBA species distribution and similar data sets of freshwater mammal and bird distribution.
Needless to say running MARXAN for freshwater biodiversity was not quite so simple. Thiem describes how “the standard’ MARXAN algorithm is designed for terrestrial reserves systems and seeks to clump reserves where possible to promote connectivity. However hydrological connectivity is linear – along river systems.” To over-come this limitation she worked with Simon Linke and Virgilio Hermoso, Griffith University who adapted a piece of the MARXAN algorithm to take into account adjacent hydrosheds and clump hydrological regions thereby promoting hydrological connectivity.
The outcome of this freshwater biodiversity system design, along with full details of the methodology is available in the 2012 Technical report Technical Report “Preliminary Results of a Freshwater Biodiversity Marxan Analysis for the Democratic Republic of Congo”. The DRC government agency responsible for protected areas has the report but Thieme is not quite sure what currently is happening with it. It is not unusual that a scientific input seemingly disappears when entering the bureaucratic policy process only to reappear some indeterminate later is a tangible on the ground change. Lets hope this is the case for freshwater biodiversity and a revised DRC protected areas system design.
In October 2000 the European Parliament adopted the Water Framework Directive (WFD), a land mark community framework to control pollution, promote sustainable water use, improve aquatic ecosystems and manage the effects of floods and droughts. The WFD requires member states to achieve “good status” for all waters by a set deadline and specifies two elements “good chemical status” and “good ecological status“.
Annex V of the WFD defines what is meant by “good ecological status” and provides technical guidelines on how it should be interpreted and measured. It states that, for all types of freshwater member states should monitor and report on four biological elements, namely:
• Composition and abundance of aquatic flora (macrophytes and phytobenthos);
• Composition and abundance of benthic invertebrate fauna;
• Composition, abundance and age structure of fish fauna.
The EU comprises a set of institutions that assure European legislation has teeth. A key role of the European Commission (EC – the executive institution) is to monitor member state compliance with directives and to facilitate the development of monitoring tools and EC regulatory oversight.
Member states, particularly those with strong fisheries institutions, responded to the requirements of the WFD by developing their own national indices for assessing water bodies and their progress towards “good ecological status”. Lead developer of the European Fish Index (EFI), Didier Pont, notes that “this was not necessarily a bad thing. It created indices attuned to national conditions and institutions. The problem was that it made an EU-wide overview of progress difficult”. It also compromised the ability of the EC to identify member states that were falling behind and identify the areas where help – or prodding – would be beneficial.
This is where the European Fish Index comes in. It was developed in two steps – first as the Common Fish Index under the FAME project (2002-2005) and later as the EFI+ under a subsequent project. The map above, included in the Global Freshwater Biodiveristy Atlas, depicts the ecological status of 2,948 sites based on application of the EFI+.
Didier Pont recollects that the main challenge in creating a common assessment and reporting standard was defining and establishing common reference conditions in each river basin and type of water body. To develop the index it was necessary to identify and model ‘reference conditions’ with no or very low human pressure.
The EFI+ was part of a wider, and particularly complex effort, known as the ‘intercalibration exercise’. This sought to integrate member state indices of ecological status into five comparable status categories: high, good, moderate, poor and bad.
Indices, such as the EFI+ are what sociologist Andrew Barry terms ‘technological zones’, specifically zones of qualification (see Barry 2006). A technological zone is a space within which technical practices, procedures, and forms have been reduced. As well as being critical to the development of economy and society (e.g. infrastructural zones association with rail & telecommunication systems, and digital technologies) they are also critical for science to interface with policy at the supra-national scale.
Interestingly technological zones, such as the EFI+, have capacity beyond being simply a ‘connection standard’ for reporting. The EFI+ has been used as a template for the design of national fish indices by the Netherlands, Sweden and Romania and is likely to be picked up by countries outside the European Union. Indeed Didier Pont notes that there is interest in using the EFI+ to assess the success of restoration projects and/or for wetland offset projects.
In short, the EFI+ empowers the EC to assure compliance with the WFD but also acts to enroll a broader constituency of countries and sectors in the goals of improving the ecological status of freshwaters.
One of the key outputs of the BioFresh project is an online portal which hosts databases on the biodiversity and function of freshwaters across Europe, which can be downloaded and used to help scientists, land managers and policy makers make informed decisions about freshwater conservation and restoration. BioFresh has recently published new datasets on the biodiversity of 460 European ponds, collected from scientific literature and unpublished sources.
Ponds are unique habitats, generally small, shallow, and highly interlinked with their surrounding environment, and can support a surprisingly large range of biodiversity. The Freshwater Habitats Trust suggests that over two-thirds of British freshwater species can be found in these often tiny habitats which pockmark gardens, parks, woodland and fields. Ponds provide pockets of habitat for a diverse range of freshwater species including dragonflies, frogs, newts and wetland birds, and can be created or reclaimed from marginal and degraded patches of land, such as in Million Ponds project.
However, ponds are not covered by the European Union’s main freshwater conservation policy The Water Framework Directive, and as such there are no strong regulations in place to protect and conserve them. As many ponds sit within urban and agricultural landscapes they are vulnerable to pollution. The Freshwater Habitats Trust suggest that over 50% of the UK’s ponds were filled in, drained or otherwise lost during the 20th century.
In response to these threats to unique pond ecosystems, The European Pond Conservation Network was set up in 2004 to promote the conservation of ponds and their biodiversity in Europe. The network, with members from European Universities and NGOs, has initiated new scientific research into the importance of pond habitats in supporting biodiversity and providing ecosystem services. The EPCN website explains in its ‘rationale‘ section that ponds not only provide important habitat for freshwater species, they also help connect different freshwater ecosystems as ecological ‘stepping stones’ across the landscape, and provide freshwater environments ‘close to home’ for people to experience, study and enjoy in urban areas – an important link between nature and culture.
For the pond database, BioFresh researchers collected data from a number of sources. Sebastian Birk describes the process: “we used peer-reviewed papers (e.g. those triggered by the European Pond Conservation Network) and grey literature (scientific reports) to provide species lists; various researchers provided their personal data collections (highly appreciated!); we were provided with the unique PLOCH (a method of sampling ponds) dataset that covered many ponds in Switzerland; and there was always a very supportive communication with the EPCN researchers.”
The BioFresh European Pond Database, which can be freely downloaded and shared, provides an important new resource for conservationists and policy makers seeking to understand the ecological importance and diversity of ponds across Europe. However, it is limited by differences in sampling techniques from data sources (e.g. there was no common measure of species abundance), and covers only a small percentage of the thousands of pond ecosystems across Europe. That said, it is an important and useful step in the right direction as part of a wider movement to help raise awareness of the importance of ponds, and conserve the wildlife that they support.
Some interesting links:
Scientists from WWF have developed a new set of tools for planning ‘greener’ human development in the Amazon Basin in South America.
This new animation explains how WWF’s Hydrological Information System – Amazon River Assessment methodology (HIS / ARA) uses scientific data on how this vast rainforest and river system functions to asses if and how development (such as hydropower schemes) might take place along the 100,000 km of freshwater in the biome whilst minimising negative impacts on surrounding ecosystems.
The animation shows how the HIS / ARA project sees the Amazon as an integrated ‘vascular system’ of interconnected ecosystems. The project models ecosystem and hydrological data from the ecosystem scale all the way up to the whole Amazon basin in order to identify priority areas for conservation. This work is intended to show the most crucial freshwater ecosystems in the wider functioning of the Amazon basin, which are likely to be irrevocably degraded by human development, and so help strengthen their conservation and protection.