State of the Bay Report 2010-Final - Anchor Environmental

Anchor Environmental
integrate changes over short periods of time (weeks to months) and are thus good indicators or
short to very short-term changes in environmental health.
Table 3.1. Ranking categories and classification thereof as applied to Saldanha Bay and Langebaan
Lagoon for the purposes of this report.
Health category Ecological perspective Management perspective
Natural
Good
Fair
Poor
No or negligible modification from the
natural state
Minimal alteration to the physical
environment, the biodiversity and
integrity of the environment remains
largely intact
Significant change evident in the
physical environment and associated
biological communities; sensitive
species may be lost, while tolerant or
opportunistic species are beginning to
dominate.
Extensive changes evident in the
physical environment and associated
biological communities, majority of
sensitive species lost, and tolerant or
opportunistic species dominate.
Relatively little human impact
Some human-related
disturbance, but ecosystems
essentially in a good state,
however, continued regular
monitoring is strongly suggested
Moderate human-related
disturbance with good ability to
recover. Regular ecosystem
monitoring to be initiated to
ensure no further deterioration
takes place.
High levels of human related
disturbance. Urgent
management intervention is
required to avoid permanent
damage to the environment or
human health.
Macrofauna: Benthic macrofauna are mostly short lived organisms (1-3 years) and hence are
good indicators of short to medium term (months to years) changes in the health of the
environment. They are particularly sensitive to changes in sediment composition (e.g. particle size,
organic content and heavy metal concentrations) and water quality.
Rocky intertidal: Rocky intertidal invertebrates are also mostly short lived organisms (1-3
years) and as such are good indicators of short to medium term changes in the environment (months
to years). Rocky intertidal communities are susceptible to invasion by exotic species (e.g.
Mediterranean mussel), deterioration in water quality (e.g. nutrient enrichment), structural
modification of the intertidal zone (e.g. causeway construction) and human disturbance resulting
from trampling and harvesting (e.g. bait collecting).
Fish: Fish are mostly longer lived animals (3-10 years +) and as such are good indicators of
medium to long term changes in the health of the environment. They are particularly sensitive to
changes in water quality, changes in their food supply (e.g. benthic macrofauna) and fishing
pressure.
Birds: Birds are mostly long lived animals (6-15 years +) and as such are good indicators of
long term changes in the health of the environment. They are particularly susceptible to disturbance
by human presence and infrastructural development (e.g. housing development), and changes in
food supply (e.g. pelagic fish and intertidal invertebrates).
State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 40