1. Species Evaluation

This version of the Puget Sound Science Update provides an initial evaluation of species indicators, but is not intended to be comprehensive. Focal species identified by O’Neill et al. (2008) were evaluated as either measures of population size or population condition. Many of these were identified as potentially good species indicators, and several may be relevant to key attributes of the other PSP goals (e.g., habitat condition).

  • The inclusion of more candidate freshwater and interface indicators, as well as indicators for population condition of marine and terrestrial species
  • Evaluation of population condition indicators other than those related to organism condition (e.g., age structure, population structure)
  • Explicitly defining vague indicators (e.g., insect species)

Commonly used data sources to evaluate species indicators included: Washington Departments of Ecology, Fish and Wildlife, and Natural Resources, NMFS, USFWS and USGS.

Indicators of population size

We focused on three metrics of population size: the number of individuals in a population, total biomass, and population dynamics. Population abundance and biomass data are key measures of the overall health of a focal species. Insight into the status and trends of a focal species can also be used to infer changes in ecosystem structure and function. While population size can be used to assess population viability, more accurate predictions of viability can be obtained by including the mechanisms responsible for the dynamics of the population. Population dynamics thus provide a predictive framework to evaluate the combined effect of multiple mechanisms of population regulation (e.g., birth and death rates, immigration and emigration) to evaluate changes in abundance through time. The Washington Departments of Ecology, Fish and Wildlife, and Natural Resources, USGS, and NMFS, among others, have ongoing monitoring efforts of population status and trends for numerous species throughout the sound.

The use of species attributes by the PSP has largely been limited to population size. For example, in the 2007 and 2009 State of the Sound documents only measures of population size were reported for all species indicators (except salmon) (Puget Sound Action Team 2007a, Puget Sound Partnership 2010). While the PSP has historically recognized the importance of monitoring species health or condition, their use of ‘condition’ was limited to measurements of toxic contaminants in various species, and was meant to be an indicator of Water Quality (see Puget Sound Action Team 2007a, Puget Sound Partnership 2010). In the following section we discuss the utility of population condition as an independent attribute for assessing the status of focal species in Puget Sound.

Indicators of population condition

Whereas the preceding attribute is concerned with measures of population size, there are instances when the “health” of the population may be of interest. For example, monitoring changes in population condition may presage an effect on population size or provide insight into long-term population viability. The dynamics of many populations are better understood through knowledge of population condition such as organism condition, age structure, genetic diversity, phenotypic diversity, and population structure. Impaired condition of any or all of these subcategories indicates biological resources at risk.

Organism condition represents both physiological and disease status. Physiological status reflects the general condition of an organism whereas disease status signals the presence of harmful agents. Thus monitoring changes in organism condition can be used to infer changes in environmental conditions. Population age structure is used to evaluate long-term stability and viability of a population by modeling trends through time. Genetic diversity measures are important in assessing population condition because loss of genetic variation can reduce individual fitness as well as the ability of populations to evolve in the future (Allendorf, F.W., et al. 2008. Genetic effects of harvest on wild animal populations. Trends in Ecology & Evolution 23(6):327-337.). Phenotypically diverse populations (i.e., each subset of the total population is adapted to a slightly different environmental condition) have an increased capacity for adapting to changing environmental conditions, which can be vital for long-term population sustainability. Similarly, insight into population structure (i.e., how different populations interact in space) can be useful for predicting the effects of changing conditions on population viability. WDFW and NMFS monitoring programs (among others) provide important information for assessing population conditions.

Evaluation of species indicators in Puget Sound

There were seventy-seven species indicators identified by O’Neill et al. (2008) and of these, we have evaluated sixty. The majority of those evaluated are indicators of population size for marine and terrestrial species. Several focal components would benefit from indicator development including Interface Species (population size and condition), Freshwater Species (population size and condition), and Terrestrial Species (population condition only). The current status of indicator evaluations for each species focal component is summarized below.

Marine species indicator evaluation

Population size. There were twenty-nine indicators of marine species population size identified (Table 4). Most of these indicators are conceptually valid, and about half those evaluated were an overall good indicator of species abundance. There were several good indicators relevant to food webs as well as key attributes for other PSP goals (e.g., habitat condition). Valuable data sources for assessing marine species abundance included (among others) WDFW, WDOE, WDNR, USGS and USFWS, and NMFS.

In general, indicators that did not perform well failed because:

  • Data are unpublished, poorly documented or does not exist
  • Unable to assess whether they respond predictably to ecosystem attributes or to management actions or pressures
  • Variation is not well understood, especially for migratory species

Indicators that performed well against all criteria included: total run size of salmonids (hatchery and wild), salmon and steelhead status and trends, marine bird aerial estimates (non-breeding populations), and pinto abalone status and trends. Pinto abalone is a unique indicator because, while it performs well against most criteria, is not necessarily theoretically-sound. A study by Rothaus et al. (2008) concluded that declines in abalone abundance are not likely to recover due to historic overharvesting, making it a poor indicator for healthy and sustaining species.

Table 4. Summary of Marine Species - Population Size indicator evaluations. The numerical value that appears under each of the considerations represents the number of evaluation criteria supported by peer-reviewed literature. For example, Pinto abalone status & trends has peer-reviewed literature supporting 3 out of 5 Primary Considerations criteria. Details can be found in the accompanying spreadsheets.

Guild

Indicator

Primary Considerations (5)

Data Considerations (8)

Other Considerations (5)

Summary Comments

Mammals

Southern Resident killer whale population trends

3

4

3

Overall good indicator of species (e.g., vital sign) but may not be best indicator of ecosystem structure & function. Also, does not respond predictably to management actions.

 

Gray whale status & trends

3

3

0

May serve as a good indicator of species abundance. Difficult to determine impacts of management actions b/c long-lived and migratory. Gray whales may be an indicator for climate change if migratory patterns shift.

 

Harbor porpoise/Dall’s porpoise status & trends

0

2

1

No evidence to recommend this as an indicator. Few studies have looked at abundances in Puget Sound, they are highly migratory, and very little information is known about populations.

 

Harbor seal status & trends

3

8

3

Overall good indicator of species abundance (e.g., vital sign), but not necessarily food webs. To avoid redundancy, choose between this indicator and harbor seal – food web interaction.

Key Fish

Total run size of salmonids (hatchery & wild)

5

8

4

Overall good indicator; peer-reviewed literature supporting most criteria.

 

Harvest of wild salmonid populations

Not yet evaluated

 

Exploitation rates of wild salmonid populations

Not yet evaluated

 

Marine bottomfish harvest

2

3

3

Theoretically-sound however, unable to determine response to ecosystem attributes or management actions/pressures. MSY estimates lacking for many marine bottomfish in PS.

 

Rockfish status & trends

1

3

1

Rockfish notes as best indicator for some ecosystem attributes [118], but due to life history characteristics, it is difficult to assess whether they respond predictably to ecosystem attributes or management. Historical harvest data available.

 

Salmon & steelhead status & trends

5

8

4

Overall good indicator; peer-reviewed literature supporting most criteria.

 

Marine resident fish species status & trends

0

0

0

Information does not exist for several of the species suggested.  Rationale for collecting these data needs to be further evaluated prior to developing this indicator.

Birds

Marine waterfowl harvest

0

0

1

Theoretically-unsound. Mostly unpublished data; marine waterfowl population numbers are not well documented, so difficult to determine the effects of harvest on overall abundances.

 

Marine bird aerial estimates – non-breeding populations

3

8

4

Overall good indicator of species abundance (no relevance to food webs). Long history of reporting that covers virtually all PSP action areas. Because a mix of residents and migrants, changes in abundance could be the result of pressures outside PS.

 

PIGU nesting colony trends

0

0

0

Poor indicator. Difficult to find any peer-reviewed literature on pigeon guillemot population numbers or nesting colony trends.

 

Marine birds status & trends during breeding season

2

8

2

Theoretically-sound and historical data available, but unable to determine response to management. Relevance to species abundance only (i.e., vital sign indicator). Underappreciated focus on locally breeding birds.

 

Marine bird breeding abundance

1

0

0

Poor indicator. There are Canadian seabird breeding datasets; equivalent datasets lacking for Puget Sound.

 

Black oystercatcher abundance

4

3

2

Good theoretical species indicator however, patchy surveys of varying levels of sampling effort, coverage, and methodologies preclude formal comparison of data. Also, not present in southern and central Puget Sound.

 

Marine bird fishing mortality

3

2

0

Theoretically-sound and relevant, but scattered reporting of bycatch in local fisheries. Complicated data analysis.

 

Glaucous wing gull abundance at nesting colonies

1

4

2

Theoretically-sound but does not meet any other Primary Considerations. Data available, mostly for north Puget Sound. Not particularly cost-effective and in general, not locally appreciated.

 

Marine birds – shore-based estimates of non-breeding populations

Not yet evaluated

 

Western sandpiper status & trends

2

3

2

Good species indicator and may also be a good indicator of habitat condition. Habitat loss is identified as main pressure, but difficult to ascertain what the impact has been on population abundance. Trend analysis of data is absent.

 

Scoter & Harlequin ducks – non-breeding populations

3

3

1

May be a good indicator of species and food webs b/c they follow herring spawning. Unpublished data sets that are regionally patchy; variation in local trends not well understood.

 

Cormorant abundance at nesting colonies

2

6

2

May be a good species and food web indicator; Slater & Byrd (2009) found bird abundance to predict changes in marine food webs [119]. Long-term monitoring programs so good data availability.

Shellfish & Other Inverts

Dungeness crab abundance

1

2

2

Theoretically-sound but does not meet any other Primary Considerations. Abundance is measurable through pre- and post-season crab pot surveys but no published data available.

 

Dungeness crab harvest

2

6

4

May be a good indicator b/c theoretically-sound and relevant to management, but year-to-year variation in harvest is not well-understood. Long-term data available from harvest report cards.

 

Pinto abalone status & trends

3

6

4

Long-term data available and relevant to management, but Rothaus et al. (2008) concludes that declines in abundance are not likely to recover due to historic overharvesting [117].

Plants

Eelgrass status & trends

Evaluated under Marine Habitats

 

Kelp status & trends

Evaluated under Marine Habitats

 

Marine macro algae status & trends

Evaluated under Marine Habitats

Population condition. There were fifteen indicators of population condition (Table 5). Most indicators were based on measures of organism condition, with considerably fewer indicators representing the other measures of population condition (i.e., age structure, population structure, phenotypic diversity, and genetic diversity). In the future, candidate indicators may need to be developed for these additional measures of population condition, especially as they relate to focal species of management concern.'''

Many of the indicators of organism condition (e.g., toxics in mussels) listed were evaluated under Marine Water Quality; we decided that for the purposes of this document, contaminant-related indicators in lower trophic level organisms provided pertinent information on water condition. Future iterations of the PSSU may choose to evaluate such indicators in relation to species condition, especially as the science develops to support the idea of population-level effects (Baldwin et al. 2009). The remaining four indicators evaluated under marine species population condition were theoretically-sound, and all but one (marine bird mortality) performed well against all criteria. These included: toxics in harbor seals, liver disease in English sole, and toxics in adult Chinook and coho salmon. Data sources mainly used to evaluate organism condition included WDFW, NMFS, Cascadia Research, Fisheries and Oceans Canada, and past PSAT reports. Several indicators including smolt to adult return for wild salmonids, salmonid diversity, star protein/DNA damage in fish, abnormal fish embryonic development, marine growth and survival of juvenile coho, and salmonid population spatial structure still need to be evaluated.

Table 5. Summary of Marine Species - Population Condition indicator evaluations. The numerical value that appears under each of the considerations represents the number of evaluation criteria supported by peer-reviewed literature. For example, Marine bird mortality has peer-reviewed literature supporting 2 out of 5 Primary Considerations criteria. Details can be found in the accompanying spreadsheets.

Guild

Indicator

Primary Considerations

Data Considerations

Other Considerations

Summary Comments

Mammals

Toxics in harbor seals

4

7

3

Good indicator but more sites are needed for Puget Sound.

Key fish

Smolt to adult return for wild salmonids

Not yet evaluated

 

Salmonid diversity

Not yet evaluated

 

Liver disease in English Sole - see also Marine Water Quality

5

8

5

Populations with elevated liver disease show symptoms of reproductive impairment and age-selected mortality. Changes in prevalence of liver disease are used to document improvements in fish health. Thresholds for PAH levels in sediment associated with increased prevalence have been defined. There is historic coverage of over 50 sites, currently limited to 8 with representing urban, near-urban and non-urban site.

 

Vtg induction in male fish

Evaluated under Marine Water Quality

 

Star protein/DNA damage

Not yet evaluated

 

Abnormal embryonic development

Not yet evaluated

 

Toxics in adult Chinook and Coho salmon – see also Marine Water Quality

3

7

4

May be a good indicator of species condition (e.g. vital sign indicator), but does not respond predictably to management actions or pressures. Long-term monitoring program for Chinook salmon was discontinued in 2006. Risk to fish health will go down with lower contaminant levels.

 

Toxics in adult Pacific herring – see also Marine Water Quality

 

 

 

Impairment to fish health increases with toxic levels in fish. Thresholds for toxics have been defined in adult herring. Sampling requires technical expertise and equipment. Historic coverage major herring population. Continuous time series for three populations from 1999.

 

Marine growth and survival of juvenile Coho

Not yet evaluated

 

Salmonid population spatial structure

Not yet evaluated

 

Toxics in English sole – see also Marine Water Quality

 

 

 

Elevated contaminant levels in English sole (including PAH metabolites in bile) increase with concentrations in the environment and elevated levels are associated with liver disease and reproductive impairment. Thresholds exist for some chemicals. Sampling requires specialized techniques and instrumentation. Historic coverage of over 50 sites, currently limited to 8 sites representing urban, near-urban and non-urban.

Birds

Marine bird mortality

2

8

2

Data has been collected all over Puget Sound since 2000. Theoretically-sound and responds to management efforts to reduce seabird bycatch. Underappreciated by management and the public b/c lower number of dead birds generally found in the sound.

Shellfish & other inverts

Benthic infaunal community structure (sediment quality)

Evaluated under Marine Water Quality

 

Toxics in mussels – see also Marine Water Quality

 

 

 

Thresholds specific to the health of mussels are not known. Continuous coverage from mid 80’s.

Freshwater species indicator evaluation

Population size. There were five indicators of freshwater species population size identified (Table 6). Of these, three have not been evaluated (mammal species, total number of spawning adult salmonids, and freshwater resident fish species). The remaining indicators, waterfowl status and trends of midwinter populations and waterfowl breeding surveys, both performed poorly. WDFW, USFWS, and the Pacific Flyway Council provide overviews of waterfowl population status and trends in the Pacific flyway region, however there are no specific references to Washington populations.

Also of note, mammal species and freshwater resident fish species may need to be more explicitly defined before they are evaluated.

Table 6. Summary of Freshwater Species - Population Size indicator evaluations. The numerical value that appears under each of the considerations represents the number of evaluation criteria supported by peer-reviewed literature. For example, Waterfowl breeding surveys has peer-reviewed literature supporting 0 out of 5 Primary Considerations criteria. Details can be found in the accompanying spreadsheets.

Guild

Indicator

Primary Considerations (5)

Data Considerations (8)

Other Considerations (5)

Summary Comments

Mammals

Mammal species

Not yet evaluated

Key fish

Total number of spawning adult salmonids (hatchery & wild)

Not yet evaluated

 

Freshwater resident fish species

Not yet evaluated

Birds

Waterfowl status & trends of midwinter populations

0

0

0

Currently a poor indicator; references provided by WDFW and USFWS provide an overview of waterfowl population status & trends, but no specific references for WA midwinter populations. More specific information is needed.

 

 

Waterfowl breeding surveys

0

0

0

Currently a poor indicator; references provided by WDFW and USFWS provide an overview of waterfowl population status & trends, but no specific references for WA midwinter populations. More specific information is needed.

 

Population condition. Six indicators of freshwater species population condition were identified (Table 7), and only one indicator (salmonid population growth rate) has currently been evaluated in this section; it received an overall good rating across all the criteria with references primarily from NMFS. Three indicators, toxics in juvenile salmon, benthic IBI and aquatic vertebrate IBI, are evaluated under Water Quality though they do pertain to population condition as well. Two remaining indicators, recruits per spawner of wild salmonids and egg to smolt survival of wild salmonids, need to be evaluated.

Table 7. Summary of Freshwater Species - Population Condition indicator evaluations. The numerical value that appears under each of the considerations represents the number of evaluation criteria supported by peer-reviewed literature. For example, Salmonid population growth rate has peer-reviewed literature supporting 5 out of 5 Primary Considerations criteria. Details can be found in the accompanying spreadsheets.

Guild

Indicator

Primary Considerations (5)

Data Considerations (8)

Other Considerations (5)

Summary Comments

Key Fish

Recruits/spawner of wild salmonids

Not yet evaluated

 

Egg to smolt survival of wild salmonids

Not yet evaluated

 

Salmonid population growth rate

5

8

4

Overall good indicator; peer-reviewed literature supporting most criteria.

 

Toxics in juvenile salmon – see also Interface Water Quality

 

 

 

Chinook salmon is an ESA listed species in Puget Sound. Age of the fish will determine whether local or regional water quality is reflected. Health-effects thresholds exist for PCBs and TBT. No consistent monitoring program in Puget Sound, however, multiple studies provide baseline data.

Shellfish & Other Inverts

Benthic IBI – macro-invert communities

Evaluated under Freshwater Quality

Key Species

Aquatic vertebrate IBI

Evaluated under Freshwater Quality

Terrestrial species indicator evaluation

Population size. There were nineteen indicators of terrestrial species population size identified (Table 8). Twelve of these indicators are conceptually valid, and about half may be good overall indicators of species abundance. Several indicators may provide relevant information to key attributes for other PSP goals (e.g., habitat area and condition). Data from WDFW and USGS Breeding Bird Survey (BBS) provided nearly all of the information on terrestrial species abundance. The residual indicators generally performed poorly because:

  • Data coverage is limited
  • Unable to determine relevance to management or response to management actions or pressures
  • Tracking or monitoring species abundance is particularly difficult

Indicators that performed relatively well against all criteria included: terrestrial game species harvest, terrestrial breeding bird counts, terrestrial bird species, and Christmas bird counts. Several indicators including deer population status and trends, elk status and trends, backyard wildlife population trends, bald eagle status and trends, cavity nesting birds, Taylor’s checkerspot butterfly, and marbled murrelets also performed relatively well against the primary considerations, but failed most of the data and other considerations criteria.

The majority of indicators that did well against the criteria are either mammals or birds, and it may be useful to develop candidate indicators for underrepresented or absent guilds (e.g., insects, plants).

Table 8. Summary of Terrestrial Species - Population Size indicator evaluations. The numerical value that appears under each of the considerations represents the number of evaluation criteria supported by peer-reviewed literature. For example, Upland plant species has peer-reviewed literature supporting 2 out of 5 Primary Considerations criteria. Details can be found in the accompanying spreadsheets.

Guild

Indicator

Primary Considerations (5)

Data Considerations (8)

Other Considerations (5)

Summary Comments

Mammals

Mountain goat status & trends

0

0

0

Poor indicator due to the inherent difficulties in tracking them.

 

Deer population status & trends

3

3

4

Theoretically sound and relevant to management. Population estimates are derived from harvest statistics (WDFW). Good species indicator and may also provide information on food webs and habitat condition since ungulate abundance can significantly affect ecosystem structure and function through browsing pressure.

 

Elk status & trends

3

3

4

Theoretically sound and relevant to management. Population estimates are derived from harvest statistics (WDFW). Good species indicator and may also provide information on food webs and habitat condition since ungulate abundance can significantly affect ecosystem structure and function through browsing pressure.

 

Backyard wildlife population trends

3

1

1

May be a good species indicator, although evidence for management relevance is lacking (but may be used to encourage citizen action). Monitoring data sources are likely to be widely dispersed and patchy in time.

 

Terrestrial game species harvest

3

7

4

Overall good indicator; peer-reviewed references support many of the criteria.

 

Mammal species

0

0

1

Currently a poor indicator b/c compilation of species where some are more extensively monitored than others. Possibly link this indicator with issues of landscape connectivity (of particular importance to mammals) to evaluate progress of landscape planning and assessment strategies.

Birds

Terrestrial breeding bird counts

3

6

4

Theoretically sound and long-term data available. Difficult to determine management relevance or response to management actions/pressures. Phenological timing of migration may serve as a useful leading indicator of climate change impacts.

 

Peregrine falcon nesting surveys

3

3

4

Does not appear to be a good indicator (theoretically unsound); lack of data in Puget Sound and variations in abundance not well understood.

 

Bald eagle status & trends

5

3

2

Overall good species indicator (e.g. vital sign) although data coverage and variability not well documented in Puget Sound.

 

Band-tailed pigeon mineral site counts

0

3

0

Appears to be a poor indicator. Linked to rare habitat type (mineral sites), but is described as being common in the region. Impacted by significant ecosystem changes from anthropogenic causes, however, other indicators highlight impacts more distinctly.

 

Christmas bird counts

3

6

4

May be a good indicator although data coverage in Puget Sound is limited. Also, evidence that indicator responds to management actions or pressures is lacking.

 

Marbled murrelet presence at occupied sites

4

0

0

Overall good theoretical indicator. WDFW has monitored abundance, but apparent reliance on at-sea monitoring has made them harder to track. Threatened species with sensitivity to habitat fragmentation, a particular development concern in Puget Sound.

 

Great blue heron

0

3

1

Do not have enough peer-reviewed evidence to support their use as an indicator. However, sensitive to development disturbance so may be useful in assessing landscape changes.

 

Cavity nesting birds status & trends

4

4

1

Overall good indicator, reflect important functional guild and indicate significant land cover change impacts on species. Historical data trends lacking.

 

Terrestrial bird species

3

6

4

May be good indicator but link to management is missing. Good data availability; migration timing may serve as leading indicator of climate change impacts.

Insects

Taylor’s checkerspot butterfly status & trends

3

4

0

May be a good indicator although difficult to attribute population declines to human pressures (thought to be due to habitat loss). Not much good data available (appears mostly anecdotal).

 

Insect species

Not yet evaluated

Plants

Upland plant species

2

0

2

Theoretically sound and responds to ecosystem attributes; data coverage is limited. Good indicator of species with relevance to ecosystem structure and function, may be anticipatory indicator through shifts in phenology.

 

Terrestrial plant species status & trends

0

0

0

Poor indicator. Upland plant species is more targeted and more relevant.

Population condition. One indicator (Avian flu) has been identified for this attribute but has yet to be evaluated (Table 9). New indicators that characterize population condition of focal species should be developed for this section.

Table 9. Summary of Terrestrial Species - Population Condition indicator evaluations.

Guild

Indicator

Primary Considerations (5)

Data Considerations (8)

Other Considerations (5)

Summary Comments

Birds

Avian flu

Not yet evaluated

      

Interface species indicator evaluation

Population size. There were two indicators identified for interface species population size (Table 10). These indicators, stillwater breeding amphibians and amphibian and reptile species, have yet to be evaluated. Additional indicators that assess population abundance of focal species should be developed for this section.

Table 10. Summary of Interface Species - Population size indicator evaluation.

Guild

Indicator

Primary Considerations (5)

Data Considerations (8)

Other Considerations (5)

Summary Comments

Amphibians & Reptiles

Stillwater breeding amphibians

Not yet evaluated

 

 

 

 

Amphibian & reptile species

Not yet evaluated

 

 

 

Population condition. No indicators have been identified for interface species population condition. Candidate indicators may need to be developed for interface focal species population condition.