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The following information was taken from the document at:
http://maps.crd.bc.ca/imf/ext/crd/jsp/definitions.htm#Overall%20Ecological%20Rating
Overall Ecological Rating
Summary rating of the ecological value of the shore unit (both intertidal and backshore
areas) based on the four ecological criteria (species diversity, habitat diversity, natural
habitat and key life cycle areas) defined below.

Overall ecological rating was determined using the criteria outlined in the following table, however
professional judgement was also used, particularly in distinguishing Very High from High, and Very
Low from Low

Ratings are relative to other units within the harbours study area. That is, shore units rated High in
the harbour area may not be high in relation to other areas of the BC coast, but are considered
ecologically significant within the VEHEAP project area.

In determining overall shore unit ratings, greater weight is given to intertidal features over backshore
features.
Ecological Rating
Very High or
High
Moderate
Rating Criteria
 High or Very High rating for two of species diversity,
habitat diversity and natural habitat, or Yes for key life
cycle areas.
 Moderate ratings for two or more criteria with no High
or Very High ratings.
 High or Very High rating for species diversity, habitat
Low or Very Low
diversity or natural habitat and no other High or Very
High ratings.
 Low or Very Low ratings for all criteria.
 Moderate for one criterion.
Species Diversity Rating
A qualitative assessment of species diversity based on observations of larger
invertebrates and plants made during the field surveys using the criteria outlined in the
following table. Professional judgement of relative species diversity in the harbours area
used to distinguish Very High from High, and Very Low from Low.

Higher species diversity is usually associated with higher marine influence or with complex,
undisturbed habitats. Lower species diversity is often associated with modified shore units, with low
marine influence and with lower habitat diversity.

In determining overall shore unit ratings, greater weight is given to intertidal features over backshore
features.

Ratings are relative to other units within the harbours study area. That is, shore units rated High in
the habour area not be high in relation to other areas of the BC coast, but are considered ecologically
significant within the VEHEAP project area.
Species Diversity
Rating
Very High or High
Moderate
Low or Very Low
Rating Criteria
 Many species observed, generally rocky shores with marine
influence, marsh areas in the intertidal zone, natural forested
areas in the backshore.
 Moderate number of species observed, often rocky shores
and mudflat habitats in areas with lower marine influence.
 Few species observed in both the intertidal and backshore
zones.
Habitat Diversity Rating
A qualitative assessment of the variety of habitats within the shore unit, based on types of
habitat (i.e. rocky substrate and mudflats) as well as shore complexity (irregular
shorelines with rock outcrops being considered more complex than a vertical seawall).
Professional judgement of relative habitat diversity in the harbours area used to
distinguish Very High from High, and Very Low from Low.

In general, greater weight is given to natural habitat complexity although pilings and floats increase
the habitat diversity rating in altered shorelines such as seawalls.

In determining overall shore unit ratings, greater weight is given to intertidal features over backshore
features.

Ratings are relative to other units within the harbours study area. That is, shore units rated High in
the harbour area not be high in relation to other areas of the BC coast, but are considered ecologically
significant within the VEHEAP project area.
Habitat Diversity
Rating
Very High or High
Medium
Low or Very Low
Rating Criteria
 Unit is heterogeneous and includes a variety of habitat
types either along shore and/or across shore. Primarily
natural shorelines.
 More that one habitat type in either the backshore or
intertidal zones, moderate degree of shoreline
complexity
 Unit is generally a homogeneous habitat type, often a
modified, straightened shoreline.
Natural Habitat Rating
A qualitative index of the amount of modification and disturbance within the shore unit.
Professional judgement of relative degree of natural habitat in the harbours area is used to
distinguish Very High from High, and Very Low from Low.
Natural Habitat
Rating
Very High or High
Medium
Low or Very Low
Rating Criteria
 Most or all of the unit's shoreline length is undisturbed,
or near natural condition, both in backshore and
intertidal zones.
 About half of the shore unit length is undisturbed or in
near natural condition.
 Most or all of the unit is modified or disturbed.
Key Life Cycle Areas Rating
The key life cycle areas rating considers 'valued habitat feature' noted in the intertidal or
backshore zones. Habitat features may be species specific, contributing to important ‘life
requisites’ of a certain species or of value for a community of species (i.e. an estuary).
Assessed as “Yes” - at least one valued habitat feature is present in the unit or “No” –
none noted. The list of valued habitat features follows:
Valued Habitat Feature
 lower intertidal sand and
mudflats
 nest tree
 riparian vegetation



 estuary

 islet

 native oysters

 tidal current community

 juvenile fish rearing
 general wildlife foraging,


rousting
Rationale
important habitat for a number of species as well as
species richness of infauna
life requisite for bird habitat
important habitat for a number of species as well as
species richness
important habitat for a number of species as well as
species richness
habitat isolated from the continuous shoreline,
important refuge areas for wildlife use
important habitat for settlement of native species of
oyster, a COSEWIC* listed species
important habitat for species diversity and richness of
sessile and suspension feeding invertebrates and
marine plants
life requisite for juvenile fish, primarily salmon
important habitat for wildlife species including birds,
otter, mink and harbour seals
*Committee on the Status of Endangered Wildlife in Canada