Annex B
Defra project WQ0112 - Understanding the impact of agriculture on aquatic ecosystems
Defra Project WQ0112
UNDERSTANDING THE IMPACT OF FARMING ON AQUATIC ECOSYSTEMS
Annex B: Indicators of Pollution
31 January 2008
Andrew Davey1
Mike Gardner1
Ian Johnson1
Stephen Nixon1
Michael Payne2
Holly Smith1
1 WRc plc, Frankland Road, Blagrove, Swindon, SN5 8YF
2 Michael Payne Environmental Consultants, Field Barn Farm, Boughton, Kings Lynn, PE33 9AH
B1 Introduction
This Annex accompanies the main report and contains more detailed background and technical information on indicators of agricultural pollution. It is divided into six main Sections:
· Section B2 collates and discusses existing knowledge on suitable indicator species for the detecting the effects of pollution, including those that could act as early warning markers.
· Section B3 summarises the sensitivity and vulnerability of diatom taxa to nutrient enrichment.
· Section B4 summarises the sensitivity of aquatic plants to nutrient enrichment.
· Section B5 details the ecological indicators that may be used to assess impacts resulting from farming activities.
· Section B6 summarises current regulatory activity and the risk assessment approaches used to prioritise veterinary medicines and pesticides.
· Section B7 reviews the nature and mechanism of impact from pesticides.
A full reference list is provided in section B8.
B2 Indicators of pollution
The aim of this Section is to collate and discuss existing knowledge on suitable indicator species for the detecting the effects of pollution, including those that could act as early warning markers. Specifically, it considers which of the ecological indicators being developed for assessing biological elements in different receiving waters under the WFD could be used in the management of pressures resulting from farming-related activities.
To achieve this:
· Section B2.1 reviews the biological quality elements and assessment methods that will be used in the management of pressures in different receiving waters;
· Section B2.2 classifies the main impacts associated with farming-related activities; and
· Section B2.3 assesses which biological quality elements and assessment methods could be used in management of impacts associated with farming-related activities.
B2.1 What biological quality elements and assessment methods will be used?
The complexity of ecosystems makes the assessment of ecosystem health challenging. Different systems respond uniquely to stress and have certain unique features vital for their individual integrity.
The UK Technical Advisory Group on the Water Framework Directive (UKTAG) has identified the requirement to have in place classification tools that cover the biological elements as defined by Annex 5 of the WFD.[1] These biological elements comprise phytoplankton, macrophytes and phytobenthos, benthic invertebrate fauna and fish fauna for rivers and lakes, and phytoplankton, macroalgae and angiosperms, benthic macroinvertebrate fauna (for transitional and coastal waters) and fish fauna (for transitional waters). Some of these elements historically are part of UK classification and assessment systems whilst others pose new requirements to support assessment of ecological status. The WFD Common Implementation Strategy (CIS) Ecostat Guidance (2003) provides further explanation on how these can be combined to assess condition and /or pressures.[2]
Table 1 summarises the assessment methods for different biological quality elements that UKTAG is developing for evaluating pressures in different receiving waters in the 1st and 2nd River Basin Planning Cycles.[3] The use of the assessment methods will depend on the need to manage different pressures in a water body. The methods include:
· those that will be addressed in the first River Basin Planning Cycle (RBPC) and are anticipated to be ready for use in 2006/07 or will continue to be developed during the first RBPC (up to 2015);
· those that will be developed in the second RBPC.
It should be recognised that not all of the elements which are relevant to farming related pressures are being fully addressed under the UK research programme. Phytoplankton in rivers are not being considered since the turnover in the majority of UK rivers is too high to support a phytoplankton community and this element has not historically been monitored. This quality element will be monitored on a risk based approach in those rivers where phytoplankton may be important. This approach is recognised as appropriate under CIS Ecostat Guidance where phytoplankton is not explicitly included in the list of quality elements for rivers in Annex V 1.1.1 but is included as element in Annex V 1.2.1. It should therefore be possible to use phytoplankton as a separate element, if needed and appropriate, especially in large and low rivers where phytoplankton may be important.
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Annex B
Defra project WQ0112 - Understanding the impact of agriculture on aquatic ecosystems
Table 1 Assessment methods for different biological quality elements
Biological quality elements / Assessment methods for different receiving waters /Rivers / Lakes / Transitional waters / Coastal waters /
Phytoplankton / None specifically identified / Composition (WFD38) – RBPC1
Bloom characteristics – RBPC1
Phytoplankton biomass [chlor] (WFD38) – RBPC1 / Composition and abundance – RBPC2
Bloom characteristics – RBPC1
Phytoplankton biomass [chlor] – RBPC1
Toolkit (see footnote 1) / Composition and abundance – RBPC2
Bloom characteristics – RBPC1
Phytoplankton biomass [chlor] – RBPC1
Toolkit (see footnote 1)
Phytobenthos / Taxonomic composition (diatoms only) (DARES)- RBPC1
Abundance (presence/absence)
Undesirabale disturbance or balance of organisms – RBPC2
Accelerated growth – RBPC2
Bacterial tufts (included in composition metric) – RBPC 2 / Composition and abundance (DALES) – RBPC1
Micro-algal tool (N-S Share Project)
Macro-algal species identification tool (N-S Share Project) – RBPC1
Undesirable disturbance or balance of organisms – RBPC1
Bacterial tufts – RBPC1
Accelerated growth – RBPC2 / Not applicable / Not applicable
Macrophytes / Taxon composition of sensitive to non-sensitive species (Leafpacs) – RBPC1
Taxon abundance of sensitive to non-sensitive species (Leafpacs) – RBPC2
Taxon composition and (relative) abundance of sensitive to non-sensitive species Free Index (Dodkins) / Taxon composition and (relative) abundance of sensitive to non-sensitive species (Leafpacs) – RBPC1
Taxon composition and (relative) abundance of sensitive to non-sensitive species Free Index (Dodkins) / Not applicable / Not applicable
Macroalgae / Not applicable / Not applicable / Abundance – RBPC1
species richness – RBPC1
distribution and abundance – RBPC1
(Toolkit – see footnote 2) / Abundance – RBPC1
species richness – RBPC1
distribution and abundance – RBPC1
(Toolkit – see footnote 2)
Angiosperms / Not applicable / Not applicable / Taxonomic composition – RBPC2
Abundance or density – RBPC2
Cover – RBPC2
(Toolkit – see footnote 3) / Taxonomic composition – RBPC2
Abundance or density – RBPC2
Cover – RBPC2
(Toolkit – see footnote 3)
Benthic invertebrate fauna / Composition and abundance (Modified RIVPACS system) – RBPC1
Ratio of disturbance sensitive to insensitive taxa (modified RIVPACS system) – RBPC1
Diversity (Modified RIVPACS system) – RBPC1
Deep Rivers Methodology (N-S Share) / Composition and abundance (N-S Share Project) – RBPC2
Ratio of disturbance sensitive to insensitive taxa (N-S Share Project) – RBPC1
Diversity (N-S Share Project)
Acidification (WFD60) – RBPC1
Chironomid pupal exuviae (CPET) – RBPC1 / Composition and abundance – RBPC1
Absence of sensitive taxa and presence of taxa indicative of disturbance – RBPC1
Diversity – RBPC1
(Toolkit – see footnote 4) / Composition and abundance – RBPC1
Absence of sensitive taxa and presence of taxa indicative of disturbance – RBPC1
Diversity – RBPC1
(Toolkit – see footnote 4)
Fish fauna / Species composition and abundance FAME-EFI – RBPC1
Species composition only HIFI – RBPC1
Age structure of fish community FAME-EFI – RBPC2 / Species composition (N-S Share Project) – RBPC1 Species abundance (N-S Share Project) – RBPC2
Type specific disturbance sensitive species – RBPC2
Age composition of fish community – RBPC2
Species composition only HIFI – RBPC2 / Species composition and abundance – RBPC2
Type specific disturbance sensitive species – RBPC2 / Not applicable
Note: 1 – Functional group succession (previously% diatoms) – RBPC1, Eelevated taxonomic abundance (previously –ve indicator taxa) – RBPC1, Community indicator taxa – RBPC1, Autotrophic/heterotrophis dinoflagellates – RBPC2, Taxa diversity – RBPC2, Phytoplankton Community Indicator Tool – RBPC2, Chlorophyll a biomass (90%ile tool) – RBPC1, Chlorophyll growth envelope – RBPC2
2 – Opportunistic macroalgae tool – RBPC1, Macrolagae: upstream fucoid penetration – RBPC1, Opportunistic macroalgae – RBPC1, Macroalgae: reduced species lists – RBPC1, Full species list – RBPC2, Subtidal macroalgae – RBPC2
3 – Seagrass: subtidal aerial cover – RBPC1, Seagrass: intertidal aerial cover – RBPC2, Subtidal density, Intertidal density, Sub-tidal diversity Intertidal diversity, Saltmarsh: habitat extent, zonation
4 - Infaunal quality index (fine sediments), Infaunal quality index (coarse sediments), Habitat extent change, Imposex, Megafauna, Sub-tidal hard stratum, Intertidal hard stratum
RBPC 1 = Ready for or being developed in the first River Basin Planning Cycle
RBPC2 = Ready for or being developed in the second River Basin Planning Cycle
Acronyms or names of methods (e.g. RIVPACS) in brackets
Source: UKTAG 2007
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Annex B
Defra project WQ0112 - Understanding the impact of agriculture on aquatic ecosystems
B2.2 What are the impacts associated with farming-related activities?
The pressures on aquatic ecosystems resulting from farming activities have been can be classified into five main groups:
· Nutrient enrichment – primarily in terms of elevated receiving water concentrations of nitrate and phosphorus.
· Organic enrichment – primarily in terms of elevated receiving water concentrations of BOD, ammonia and soil sediment.
· Acidification – in terms of changes in pH and associated water chemistry in affected freshwater bodies.
· Pollutants – in terms of elevated receiving water concentrations of pesticides veterinary medicines and endocrine disrupting chemicals released following use of particular products.
· Habitat alteration – in terms of increased sedimentation resulting from soil erosion.
B2.3 Which biological quality elements and assessment methods could be used in management of impacts associated with farming-related activities?
B2.3.1 What biological quality elements are likely to be used to assess the impact of impacts associated with farming-related activities?
Table 2 presents the parameters that UKTAG considered most appropriate for assessing impacts relevant to the impact of farming activities on aquatic ecosystems. This has been supplemented with information from the WFD CIS Working Group on Monitoring. Clearly these vary depending on the nature of the pressure and the receiving water. The process of determining which parameters have the best correlation for assessing pressures and impacts is underway.
Table 2 Biological quality elements likely to be used to assess pressures relevant to the impact of farming activities (UKTAG 2005[4])
Pressure / WFD biological quality elements for different receiving waters /Rivers / Lakes / Transitional waters / Coastal waters /
Nutrient enrichment / Phytobenthos
Macrophytes / Phytoplankton
Macrophytes
Phytobenthos / Phytoplankton
Macroalgae
Angiosperms
Benthic invertebrates / Phytoplankton
Macroalgae
Angiosperms
Organic enrichment / Benthic invertebrates / Benthic invertebrates
(Profundal invertebrates) / Phytoplankton
Benthic invertebrates
Fish / Benthic invertebrates
Acidification / Phytobenthos
Benthic invertebrates
(fish) / Phytobenthos
Benthic invertebrates / Not applicable / Not applicable
Pollutants / Benthic invertebrates / Benthic invertebrates / Macroalgae
Benthic invertebrates / Macroalgae
Benthic invertebrates
Habitat alteration / (Macrophytes)
Fish / (Phytoplankton)
(Macrophytes)
(Benthic invertebrates)
Fish / Angiosperms
Benthic invertebrates
Fish / Angiosperms
Benthic invertebrates
Notes: Elements in bold are likely to have the strongest sensitivity to the pressure
Elements in brackets require further work as more data is acquired
Elements underlined in italics recommended by CIS WG2.7[5]
B2.3.2 What indicators are associated with a biological quality element?
Potential indicators range from sub-organism level parameters (e.g. tissue analysis of persistent bioaccumulative substances in an appropriate species) through the presence and abundance of key species, to indices which integrate information about the structure or function of whole biological communities.
Several different types of ecological indicators exist and those chosen depend on their required role in the assessment process. Ecological indicators can be divided into three classes[6]:
1. early warning indicators that detect impending changes;
2. compliance indicators that detect changes in characteristics beyond acceptable limits;
3. diagnostic indicators that show the causes of deviations from “normal conditions”.
Indicators are commonly used to determine the impact of various pollutants and disturbances. The indicator used for a defined part of the monitored system needs to be able to inform stakeholders about the threat to a given element of the ecosystem.[7] The results should be unambiguous in their response to pressures, although this may not always be possible given the complexity of the systems being monitored.[8] The validation process is important, but unfortunately is rarely fully implemented. [9]
This review focuses on standardised methodologies which are currently available for measuring the impacts of farming-related pressures on a particular biological quality element. The methods reviewed are largely those that have traditionally been used in the United Kingdom and are being developed further by UKTAG. Consideration has also been given to the evaluation of whether the changes in the presence and abundance of particular species within these methodologies can be used as early warning indicators of impacts.
Figure 1 shows the required relationship between indicators and one or more pressures for a method to be useful in the management process. The expression of the indicator should be directly related to changes in the pressure (e.g. the receiving water concentration) so that the implications of changes in the indicator are evident. Furthermore there should be an understanding of the variability in the relationship so that stakeholders can assign a level of uncertainty to any management decisions that are based on the ecological indicator data.
Figure 1 Required relationship between ecological indicator and one or more pressures for a method to be useful in the management process
Table 3 summarises the characteristics of an ideal indicator to assess the status of a defined part of the monitored system (e.g. phytoplankton, phytobenthos, macrophytes, macroalgae and angiosperms, benthic invertebrates and fish).[10],[11]
Table 3 Characteristics of an ideal indicator to assess the status of a defined part of the monitored system
Type of characteristic / Characteristic / Requirement /Response characteristics / Discrimination / The response should be graded following exposure rather than an all-or nothing to allow for classification
Control of confounding factors / Physico-chemical factors that may confound interpretation of the impact of pressures (e.g. pH, salinity and temperature) should be controlled
Scientifically defensible / The links between responses and exposure to pressures should be well established
Clarity / The information produced should be easily understood by stakeholders
Practicality / Cost / Measurement should involve low costs in terms of staff time and equipment
Rapidity of measurement / There should be a short time from sample collection to the generation of results
Requirement for highly trained personnel / Procedure not limited to highly trained personnel
Precision and
accuracy / Validated procedure / Field data should be available that confirms the utility of the indicator
Repeatability / Consistent results should be obtained within a set of samples measured by one operator
Reproducibility / Consistent results should be obtained within a set of samples measured by different operator
In this review of potential early warning indicators attention has focused on the response and precision and accuracy characteristics of a method. If the methodology does not satisfy these criteria then those associated with practicality become less important.