Ecological indicators

This page is meant to describe the outline and reasoning behind the template used for each individual indicator.

 Indicator summary

Two tables....any more info needed here?? to explain them?

Definition

Individual indicators

• Indicators can be used to present the data in a way that represents the broader significance or implications of the data compared to the raw data on its own (Vandermeulen 1998).

• Can be a useful tool within management frameworks for purposes of communication and decision making (Vandermeulen 1998).

• Can provide information on trends in the conditions of a phenomenon and has significance extending beyond that associated with the properties of the statistics itself (Vandermeulen 1998).

Simple indicators have been found out perform more complex (model based) ones, which are sensitive to data quality (Fulton et al 2005, Link 2005).

There is consensus on the need for multiple rather than a single indicator and on the types of indicators that perform well regardless of system type (Medley et al 2009).

"Ecosystem indicators are generally accepted as tools for evaluating ecosystem status and trends (e.g. Shin & Shannon 2010, Shin et al. 2010a,b), identifying key ecosystem processes (e.g. Ojaveer & Eero 2011), serving as signals that something is happening beyond what is actually measured (NRC 2000), and assessing the impacts of human activities and climate forcing (e.g. Coll et al. 2010, Link et al. 2010b, Ojaveer & Eero 2011)." (Fu et al 2012).

Indicator performance can be quantified by the ability to detect and/or predict trends in key variables of interest (attributes) (Fulton et al 2005).

Community indicators in fisheries - the criteria used for the evaluation of these indicators are (Rochet and Trenkel 2003):

• meanings - "Does the indicator have an understandable relationship with the state and dynamics of animals in the community?". Assigning meaning is subjective and subject to criticism.
• expected effect of fisheries - "How does the indicator change under the effect of fishing pressure?". There are three categories (1) unpredictable indicators, (2) sensitive indicators with a reference direction and (3) sensitive indicators with reference points.
• exclusiveness to fishing effects - "Is the indicator exclusive to fishing, ie is it not expected to vary under the influence of other factors than fishing?".
• measurability - "Is the indicator easily measurable?". These were split into 'usually available' data and those that needed additional data/information.
  
  

(Fulton et al., 2005; Link, 2005) has shown that it is critical that:

• a suite of indicators, which are not all highly correlated, is used;
• multiple time and space scales are spanned by the data sets

It is also critical that data include species that (Medley et al 2009):

• are directly impacted;
• have high turnover rates, which may provide a noisy but early warning;
• define the habitat, as these often have a disproportionate or keystone role in the system; and
• are from the upper trophic level, which are typically both vulnerable in their own right due to their life history characteristics, but also integrative of pressures and patterns at large scales. 

Attribute

Possible examples of ecological attribute(s) that are related to each indicator includes (Fulton et al 2004):

• ecosystem structure -
  
• ecosystem function
• community structure
• community function
• Eutrophication
• trophic shifts
• trophic structure
• habitat quality
• discard availability
• population structure
• predator-prey balance
• community heterogeneity
• habitat condition
  
• efficiency of by-catch reduction measures 

Add a definition for each of the above

Purpose

Pick one or more of the following:

• fisheries
• seabirds/penguins
• mammals
• phytoplankton
•  ....others??

Taxa

Data required

what data is required to calculate this indicator?

Ecosystem applicability

where can this indicator be used? all over or just locally ie:

• applicable to all ecosystems
• only for specific systems (eg temperate, inshore, etc)
• currently only for specific systems but may be used for wider ecosystem with more information??

Identified capability

explain how defining demonstrable from aspirational indicators.

• describe check list of points on how decide...ie list of yes/no question that I ask in order to define it as one or the other.
• what tests am I using to allow a species indicator to be used as a higher level (community of whole ecosystem) indicator.

is it demonstrable or not?

ideally want them all to be demonstrative rather than aspirational ...

demonstrable =  this definitely shows this by these studies, data sets, etc.

aspirational =  this may show this we think but have no data or studies to back it up..which just think that it is a link that can be made.

Biological classification level

The indicators listed in this wiki are classified into hierarchical levels of organisation (based on those described by Fulton et al (2004)) and then subdivided into drivers, ??themes?? and finally into individual indicators. The top five level of classification are species, population, assemblage, community, and ecosystem. Fulton et al (2004) do not include a species level but does include an individual level which they describe as being highly restricted and of uncertain benefit.

Hierarchical level

The species level focuses on behavioural and metabolic responses (Fulton et al 2004).

The population level focuses on behaviour, demographic, metabolic and genetic responses and includes biomass, production and size structure (Fulton et al 2004). These examples are often used an proxies of population health and can also potentially be used for community and ecosystem proxies. Population level indicators are the most operational indicators because they (Fulton et al 2004):

• are more easily interpreted
• have a greater level of understanding of their properties and how they effect fishing (reference points are more easily set for these types of indicators)
• show that if individual species in the ecosystem are conserved then it is difficult to say that the ecosystem is not being preserved. 

Currently there is a better understanding and familiarity with population indicators and sound theoretical bases which makes then attractive candidates as surrogates for more general effects of fishing on ecosystems. Although more scientific understanding is needed to evaluate their true worth as long term indicators of ecosystems. Population indicators are good indicators of the state of a particular species but are less certain when used as proxies for community and ecosystem attributes (Fulton et al 2004).

• (e.g. mortality rate, exploitation rate, or average length) are the most operationally useful indicators because their meaning is clear and the expected effect of fisheries on them is well understood, , ie. reference points can be set (Rochet and Trenkel 2003).
• first step from single-species to community assessment and management. These indicators have the goal of preserving population states, structures and dynamics (Rochet and Trenkel 2003).

The assemblage level refer to populations living together in a biotope, ignoring interactions. These indicators describe the range of populations and the distribution of their characteristics that may be effected by fishing (Rochet and Trenkel 2003). The goal of these indicators is to preserve diverse assemblages.

The community level concentrates on species richness, diversity and habitat structure and is primarily concerned with community and trophic structure and the processes or environmental conditions that support these structures (Fulton et al 2004). There are some problems with community indicators including that:

• they do not only respond to changes in fishing but also to changes in natural regime shifts and eutrophication
  
• fisheries dependent data can be bias by shifts in market forcing and technology advances
• reference points are not easily identified because need unexploited regions to determine the reference points, of which there are few.
  

from definition page for community indicators:

• are networks of interacting populations or individuals
• the goals of these indicators is to assess the effect of fishing on the interactions, the tropic paths, and the biomass flows in the community
• and for the preserving of the above functions of the community (Rochet and Trenkel 2003). 
• ways of using community indicators:
  • do not worry about using reference points and instead examine whether the indicator is currently changing
  • determine theoretical reference points
  • develop an empirical reference system, which can be developed by gathering indicator estimates from several communities

The ecosystem level includes entire ecosystem processes such as production or overall tropic structure and include indicators such as productivity, nutrient cycling and diversity. There have been very few ecosystem studies completed and therefore most ecosystem indicators have been developed from ecological theory or from ecosystem models (Fulton et al 2004). The types of ecosystem indicators include:

• estimates of changes in the community biomass as a result of fishing down the food web (FIB)
• measures of productivity
• departure of Redfield ratio ???
• ratio of biomass of demersal and pelagic species.

There are some problems with ecosystem indicators including, that they are not good early warning indicators, are less sensitive to change and the best indicators are entirely based on models. These models are still in development and need more rigorous scrutiny therefore indicators may not be as robust as lower level indicators (Fulton et al 2004). There are also some good aspects to ecosystem indicators; they are good at describing ecosystem health and are more suited to performance reporting than to decision making (Fulton et al 2004).

Response variables

Size-based indicators (SBIs) -

• is the statistical summary of the size distribution of fish assemblages and populations. The size of an organism is a central factor to key ecological processes. The changes in size distribution may have many ecological or physical causes, including genetic or environment variability in life history characteristics, predictor-prey relationship, and competitive interactions (Shin et al 2005).
• Fishing is always size selective (ie, nets used, target species and by-catch).
• 'Are typically used to describe teh response of communities or individuals populations to exploitation and may contribute to the development of an ecosystem approach to fisheries' (Shin et al 2005).
• Size based indicators are evaluated for their relevance by Shin et al (2005). The theoretical and empirical modelling bases are examined, then their measurability (sampling constraints, availability of size data, potential biases), sensitivity to fishing effects, responsiveness (time of response) and specificity (discrimination of fishing and environmental effects) are examined.

Species-based indicators -

• diversity indices and ordination of species abundance are difficult to interpret, and the effects of fishing is not easily predicted.

Trophodynamic indicators -

• are most relevant to the mean trophic level of community and the demersal-to-pelagic biomass ratio (Fu et al 2012).

Environmental indicators -

• are are most likely related to total system biomass and biomass of specific biological groups variables, (Fu et al 2012).

Drivers

The drivers as described in various studies (eg Fu et al 2012; Pranovi et al 2012 and Link et al 2010) are anthropogenic, trophodynamic and environmental. These three drivers are the main processes that regulate the production dynamics of a marine ecosystem (Link et al 2010). There are plenty of studies that have shown who each of these drivers acts singly on a system and only recently have studies begun to look at multiple drivers assessed simultaneously (Link et al 2010). The driver can be divided into two types; anthropogenic and environmental drivers are external to the ecosystem and whereas trophodynamic drivers are not. As a result of this relationship anthropogenic and environmental driver can strongly influence trophodynamic drivers in an marine ecosystem (Pranovi et al 2012).

The anthropogenic drivers

• also called fisheries drivers 
• encompasses fisheries exploitation.
  
• They tend to be related to catch-based indicators (Fu et al 2012).
•  Fisheries drivers can be derived from the catch time series for an ecosystem. (Fu et al 2012).
  
• These can be analysed on a species basis, in feeding guilds, or by combining feeding guilds. (Fu et al 2012).

The trophodynamic drivers

• tend to be related to the mean tropic level of the community. (Fu et al 2012).
  
• Can also be called trophodynamic interactions.
• include time series related to predator-prey of fishes species.(Fu et al 2012).
• used to examine bottom up and top down effects on fisheries production. (Fu et al 2012).
  

The environmental drivers (also called biophysical)

• looks at local and basin scale climate factors.
  
• Temperature one of the strongest environmental drivers. (Fu et al 2012).
• represent thermal or broad-scale oceanographic features that are influential in an ecosystem. (Fu et al 2012).
• examples include: SST, various ocean oscillation and indexes, stratification, freshwater discharge, sea ice cover.

Robustness

The robustness level of each indicator is based on the definition outlined in Fulton et al (2004) Final Report -

Many of the descriptions of the different types of indicators given below refer to a robustness rating. This is a subjective rating (low, medium, high), given to each indicator reviewed by Fulton et al. (2004a), that was based on a literature review (and where necessary an expert judgement) on the conceptual foundation, feasibility of implementation, ease of accurate collection, sensitivity, exclusiveness, comprehensiveness and clarity of potential indicators (Jackson et al. 2000, ICES 2001, Rochet and Trenkel 2003, Fulton et al. 2004a, Niemi et al. 2004, Rice and Rochet 2004, Rochet and Rice 2004). While some preliminary indicator assessment frameworks were trialed during the early stages of this project, in collaboration with members of the SCOR working group 9 (WG9) on the quantitative indicators of the ecological effects of fishing, the ratings ultimately subjective, as no tested quantitative selection criteria existed when the review took place. The final form of the SCOR WG9 indicator evaluation framework does appear to show substantial promise, but they have come too late for inclusion in this study.

In general, a poor rating based on this subjective system did mean an indicator was dropped from further consideration by simulation testing. However, if an indicator has been strongly advocated in the past, is already widely used, or if field work had indicated that it may actually have potential, then it was included (if possible given the form of the model) regardless of rating.

is there were could include discussion about type I and II errors...or are we talking statistical errors in calculating the indicator? or both?

Current status and trends

what was it like in an undisturbed/unexploited system?

how would it be expected to change?

which way is the indicator showing a population is going in?  decreasing or increasing ??

The trend associated with meeting an operational objective can be a limited or target reference point, trajectory or direction.

Target stock use in management plans has a tradition of setting reference points  (Jennings 2005). In other fields a reference point can not be made therefore a trajectory or reference direction is used instead. See figure below from Jennings 2005 for an example of points, trajectories and directions. The unexploited, target, precautionary and limit are reference points where as the green arrows are the trajectories or reference directions. These are all measurement of progress of the management performance.

"Reference points that might support management decision making are: 1, reference points for no impaxct, 2. limit reference points fr the values of indicators associated with serious or irreversible harm, and 3, target reference points for preferred values of the indicators. As indicator values include error, precautionary reference points may be used to guarantee a high (preferably specified) probability of avoiding a limit" (Jennings 2005).

Management strategies and/or objectives

define a standard set of management objectives?? ie from Indiseas

• Conservations biodiversity
• Ecosystem stability and resistance to perturbations
• ecosystem structure and functioning
• resource potential

has it been used in a management strategy? if so how?

relationship to management strategies/ objectives

Stakeholder/public acceptability

Acceptability with stakeholders

• by all stakeholder
• by the public
• understandable to the stakeholders

Associated links

website set up to provide a map interface for describing indicators, provide background and overview of the status of their ecosystems - http://www.indiseas.org/

Journal dedicated to ecological indicators - http://www.journals.elsevier.com/ecological-indicators/

Special edition of ICES Journal of Marine Science (2005) - http://icesjms.oxfordjournals.org/content/62/3.toc

Fish and Fisheries special edition (2011) - http://onlinelibrary.wiley.com/doi/10.1111/faf.2011.12.issue-2/issuetoc

Marine Ecology Progress Series (2012) Theme Section of this volume - http://www.int-res.com/abstracts/meps/v459/

References

Fu, C., Gaichas, S., Link, J.S., Bundy, A., Boldt, J.L., Cook, A.M., Gamble, R., Utne, K.R., Liu, H., and Friedland, K.D. (2012) Relative importance of fisheries, trophodynamic and environmental drivers in a series of marine ecosystems. Marine Ecology Progress Series, 459, 169-184.

Fulton, E.A., Fuller,M., Smith, A.D.M., and Punt, A. (2004) Ecological indicators of the ecosystem effects of fishing: Final report. AFMA Final Research Report, report Number R99/1546.

Fulton, E.A., Smith, A.D.M., Webb, H., and Slater, J. (2004a) Ecological indicators for the impacts of fishing on non-target species, communities and ecosystems: Review of potential indicators. AFMA Final Research Report, report Number R99/1546.

Fulton, E.A., Smith, A.D.M. and Punt, A.E (2005) Which ecological indicators can robustly detect effects of fishing? ICES Journal of Marine Science. 62, 540-551.

Jennings, S. (2005) Indicators to support an ecosystem approach to fisheries. Fish and Fisheries, 6, 212-232.

Link, J.S.,Megrey, B.A., Miller, T.J., Essington, T., Boldt, J., Bundy, A., Moksness, E., Drinkwater, K.F. and Perry, R.I. (2010) Comparative analyssi of marine ecosystems: international production modelling workshop. Biology Letters 6, 723-726.

Medley, P.; Cheung, W.; Fulton, B.; Minte-Vera, C. (2009) Multispecies and ecosystem indicators, and biomass-fleet dynamics stock assessment: an initial evaluation. FAO Fisheries and Aquaculture Circular. No. 1045. Rome, FAO. 28p

Pranovi, F., Link, J., Fu, C., Cook, A.M., Lui, H., Gaichas, S., Freidland, K.D., Utne, K.R., and Benoît, H.P. (2012) Trophic-level determinants of biomass accumulation in marine ecosystems. Marine Ecology Progress Series, 459, 185-201.

Rochet, M-J. and Rice, J.C. (2005) Do explicit criteria help in selecting indicators for ecosystem-based fisheries management? ICES Journal of Marine Science. 62, 528-539.

Rochet, M-J. and Trenkel, V.M. (2003) Which community indicators can measure the impact of fishing? A review and proposals. Canadian Journal of Fisheries and Aquatic Sciences, 60 (1) 86-99.

Background reading

Other references that would be useful to read in regard to the indicator referred to on this page.

Citation

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