SIP
The condition of South Africa’s Estuaries
Lara van Niekerk
Wilderness, June 2016
Thank you
Project team
2
• CSIR
• SANBI
• NMMU
• DAFF
• ORI
• Anchor Environmental
• SAIAB
• SAEON
• Ezemvelo KZN WildlifeANCHORe n v i r o n m e n t a l
Thank you
Outline
2
• Pressures
• Measures of condition assessment
• Estuary condition
• 2009 vs 2015
• Conclusions
• Way forward
Thank you
Limited number of estuaries…
~ 300 estuaries
+/- 200 inlets/outlets
Thank you
Data collation
2
• WRC Desktop provisional EcoClassification of the
Temperate estuaries of South Africa (Orange to Mbashe)
• Mvoti to Mzimkulu WMA
• Gourits WMA Reserve study
• Usutu WMA Reserve Study
• A Desktop assessment of the Ecological Condition of South
Africa’s Temperate – Subtropical Transition Zone Estuaries
based on a Provisional EcoClassification
Estuary Health Index….
Estuarine Health
Abiotic health Biotic health
50 50
Mic
roal
gae
Ph
ysic
al h
abit
at
Wat
er
Qu
alit
y
Mo
uth
Co
nd
itio
n
Hyd
rolo
gy
Bir
ds
Mac
roal
gae
Inve
rteb
rate
s
Fish
25 252525 202020 20 20
Condition and Functionality….
Condition ≥91% 90-75 75 - 61 60 - 41 40-21 ≤20
Category
A
Natural
B
Largely natural / few
changes
C
Moderately modified
D
Largely modified
E
Highly degraded
F
Extremely degraded
State Excellent Good Fair Poor
FunctionalityRetain
Process & Pattern (representation)
Loss of Process or Pattern
No / limitedProcess & Pattern
Flow modification Bait collection
Pollution Infrastructure
Fishing pressure
Habitat degradation
Mean Annual Runoff
6 100 (45%)
5 200 (72%)
13 600 (85%)
36 900 24 900 (67% remaining)
Thank you
Emerging pressures….
• Invasive aliens
Spartina alterniflora
Tarebia granifera
• Desalination
• Aquaculture (e.g. catfish and red claw crayfish)
• Pathogens
South Africa Estuary condition
Measures of estuary condition
Estuary Condition by biogeographical region
2011 vs 2015: Estuary Condition
2011 vs 2015: Hydrology
2011 vs 2015: Water Quality
Thank you
Conclusions……
2
• Filled flow and water quality gap with models
• Revisited >95% of systems since 2009
• Only 4 system not revisited:
• Tugela/Thukela
• Siyaya
• Mhlathuze/ Richards Bay
• Nhlabane
• Desktop assessment model is becoming an official DWS
tool
• Same assessment tools for NBA, EWR and Estuary
Management Plans
Thank you
Way forward…
2
• Refine Estuary Functional Zone
• Saltmarsh and swamp forest
• What about land-estuary transitional zone????
• Revised estuary classification
• Include micro-estuaries, Langebaan
• Ecosystem threat status / Protection levels
Thank you
Van Niekerk L, Adams JB, Bate GC, Forbes AT, Forbes NT, Huizinga P, Lamberth SJ, MacKay CF, Petersen C, Taljaard S, Weerts SP, Whitfield AK and Wooldridge TH. (2013). Country-wide assessment of estuary health: An approach for integrating pressures and ecosystem response in a data limited environment, Estuarine, Coastal and Shelf Science 130: 239-251.
Veldkornet, DA, Adams, JB and van Niekerk, L (2015): Characteristics and landcover of estuarine boundaries: implications for the delineation of the South African estuarine functional zone, African Journal of Marine Science, DOI: 10.2989/1814232X.2015.1072111.