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BERG RIVER MONITORING PROGRAMME

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Announcements

Surveys


Biological Characteristics of the Water Resource


River macroinvertebrate fauna
Fish
Vegetation
Estuarine invertebrates
Cladophora monitoring
Avifauna monitoring

River macroinvertebrate fauna
a) Monitoring invertebrate assemblage change and biodiversity
Excellent quantitative historical data on invertebrate assemblage composition exist for the Berg River. Collection of SASS data will be sufficient to track changes in invertebrate assemblages. SASS collections will be made for each hydraulic biotope separately, as stipulated in the latest version of the SASS protocol (SASS5).
The analysis of SASS data is important. Traditionally, SASS scores are used to provide an index of species richness and of water quality. In the IFR monitoring programme conducted by The Freshwater Consulting Group on the Koekedouw River, downstream of the new Ceres Dam, the use of actual community data (i.e. presence/absence or semi-quantitative data on invertebrate families) in multivariate analysis has been an excellent instrument to depict change in community structure over time in a graphical and easily interpretable manner. SASS-level monitoring will allow both these analytical techniques to be used, providing two quite different measures of change.
In addition, because of the emphasis placed on maintaining species diversity in the IFR process, it is important that this aspect is also specifically monitored in the baseline and IFR monitoring programmes. True measures of diversity (such as the Shannon-Weiner Index) require quantitative sampling to be undertaken which is very costly and time consuming. We believe that "diversity" in this case is adequately reflected by species richness - which could easily be undertaken through identification of species in the SASS samples. Species would be selected from the samples in the field and returned to the laboratory for identification, to avoid having to preserve and then process large samples. These species lists could be compared with historical data, given that each of the sites proposed was comprehensively surveyed in 1958 and 1991.

Data collection:
· SASS monitoring at all sites, per biotope
· Collection of species present in the SASS samples, with potential additional (15 minute) collections in the field
· Identification and curation of the species samples

Monitoring frequency:
· Seasonal (4 times annually) data collection will provide a measure of seasonal variation in community structure.

Deliverables: · Initialisation report - synthesis of existing information regarding ecosystem structure and function.
· Annual reports including details of sampling programme, compilation of data collected and brief interpretation of the significance of observed changes.
· Input into final baseline monitoring report

b) Monitoring the regulation of periphyton, invertebrate and detritus biomass by flood flows
This study will examine the effects of floods of different magnitudes on invertebrate and periphyton abundance and diversity, as well as the availability of benthic detrital matter. Fieldwork and reporting will be conducted within the first year of the monitoring programme. Six pre- and post-flood visits to the river (Sites 1 and 2) will be undertaken, mainly in winter, but also representing biomass reductions due to small flood pulses in the other seasons. The data would be linked to the magnitude of floods at the DWAF gauge. It would also allow for predictions of invertebrate biomass build-up during winter months, should inadequate (magnitude or frequency) floods be released from the dam.

Data collection:
Pre- and post-flood monitoring at Sites 1 and 2, of:
· invertebrate biomass on and immediately under stones,
· periphyton density (Chla),
· Accumulated biomass of detritus (CPOM and FPOM).

Monitoring frequency:
· Six sampling trips during 2003.

Deliverables:
· Report attached to the Invertebrate Final baseline monitoring programme report.

Fish
Fish are considered to be particularly good indicators of ecosystem health and of ecosystem change as they feed at or near the top of the food chain and hence reflect the integrated effects of a wide array of environmental factors (chemical, physical and biological). Monitoring of fish populations in the Berg River will be given high priority status in this study.
Fish populations along the river will be monitored using electroshocking and / or seine netting. Data will be compared with historic information on fish species in the river and other nearby systems with a view to determining the reference state of the Berg River and to determine future requirements in terms of:
· maintaining current species diversity,
· rehabilitating the river to allow re-introduction of indigenous species where these no longer occur (e.g. witvis Barbus andrewi)
Estuarine and floodplain fish will be monitored using seine and gill nets at 25 sites extending from the mouth to the upper parts of the estuary. These will be tied into the surveyed transects. Species of regional importance, and habitat use by fish fauna, will also be established. Attempts will be made to link changes in water fish numbers, diversity and habitat use to changes in the physic-chemical characteristics of the river and estuary.

Data collection:
Annual survey data will include the following:
· catch composition by species,
· habitat utilisation
· catch per unit effort.

Monitoring frequency:
· Annual (January/February) survey in river and estuary
· Additional winter once-off survey in 2003, to examine estuarine and floodplain utilization at this time of year.

Deliverables:
· Initialisation report - synthesis of existing information regarding ecosystem structure and function.
· Annual reports including details of sampling programme, compilation of data collected and brief interpretation of the significance of observed changes.
· Input into final baseline monitoring report

Vegetation
Riparian vegetation along the river will be monitored through application of the River Vegetation Index (RVI), combined with transect-mapping of vegetation. The present RVI methodology, originally developed for use on summer rainfall rivers in the Mpumalanga area, is not necessarily appropriate to the Western Cape (winter rainfall) river systems. This component of the monitoring programme thus aims to adapt and refine the present RVI methodology, working in collaboration with other botanical experts and will feed into the national revision of the RVI. Thus monitoring of the Berg River should include a wider set of variables than presently measured for the RVI, to include the sort of measures that are likely to be incorporated into revisions of this index. This will allow for continuity with future revisions of the RVI, which is particularly important if the RVI (or its modified version) is anticipated to be the long-term monitoring strategy for the river.
During the final year of the monitoring programme, a one-day capacity building workshop will be provided to DWAF personnel (relevant personnel to be selected by DWAF) for training and skills development in the locally adapted and refined RVI methodology. The venue and costs of materials (e.g. manuals) required for this workshop, as well as the organisation of participants, will be provided by DWAF (River Health Programme). A first task regarding the monitoring of floodplain vegetation will be to update the existing vegetation maps of the floodplain. This will include the provision of digitised maps and descriptions of plant communities, and a description of changes relative to existing maps of floodplain vegetation.
Monitoring of floodplain vegetation will take place along an estimated 50 short transects, selected after initial mapping. These will be established along vegetation community transition zones (vegetation unit boundaries), where change is likely to be noticed first. Transects will be geo-referenced and linked to the DTM of the floodplain.
Three cross sections spanning the width of the estuary channel will also be monitored: these are to coincide with three of the surveyed sections.

Data collection:
· RVI and plant transect data at five biomonitoring sites.
Re-mapping of floodplain vegetation will include:
· digitised vegetation maps
· descriptions of plant communities, based on species identifications and assessment of dominance,
· a description of changes relative to existing maps of floodplain vegetation.
Estuary channel and short floodplain transect survey data will include the following:
· vegetation mapping along the transect,
· marking and measuring of selected plants in plots on either side of the transect lines
· fixed-point photographic records of vegetation and selected indicator plants.

Monitoring frequency:
· Once-off (November 2002) re-mapping of the floodplain
· Annual (December / January) survey in river and estuary, to coincide with re-survey of cross-sections.

Deliverables:
· Initialisation report - synthesis of existing information regarding ecosystem structure and function.
· Maps with report on floodplain vegetation to be included in the Berg River Initialisation Report
· Annual reports including details of sampling programme, compilation of data collected and brief interpretation of the significance of observed changes.
· Input into final baseline monitoring report

Estuarine invertebrates
This component of the study will include a survey of the intertidal, benthic subtidal and zooplankton invertebrate fauna of the estuary and flood plain areas. A minimum of 12 stations will be sampled extending from the mouth to the upper parts of the estuary. These will be tied into the surveyed transects. At least two of these stations should be located in temporary/semi-permanent/permanent pans on the floodplain. Replicate samples will be collected using core (intertidal), grab (subtidal), hyperbenthic sled (subtidal) and zooplankton nets. Attempts will be made to link changes in invertebrate numbers, diversity and habitat use to changes in the physic-chemical characteristics of the river and estuary.

Data collection:
Data will include the following:
· species composition of invertebrates,
· richness, density and seasonal variability
· habitat utilisation

Monitoring frequency:
· Annual (January) survey

Deliverables:
· Initialisation report - synthesis of existing information regarding ecosystem structure and function.
· Annual reports including details of sampling programme, compilation of data collected and brief interpretation of the significance of observed changes.
· Input into final baseline monitoring report

Cladophora monitoring
The extent and biomass of Cladophora on mud banks of the Berg River Estuary will be studied from September to April of each year. Cladophora is reported to start growing in September; reaches peak biomass in January, and by March has already started decaying from the heat (Dr Phil Hockey, University of Cape Town, pers. comm.). Measurement of the extent of Cladophora cover on mudbanks will thus be undertaken fortnightly from September through April of each year (each Spring Tide) to compare the dynamics of Cladophora with physical variables such as flow and salinity. Biomass measurements will be made less frequently (twice per annum) to develop the relationship between percent cover and biomass.

Data collection:
Monitoring will include the following:
· % coverage by Cladophora of mudbanks at six sites, tied in to the survey cross-sections.
· wet biomass on in areas of 100% coverage,

Monitoring frequency:
· Sampling to measure % cover will take place with each Spring Tide over the 8-month period
· Biomass - cover measurements will take place twice annually

Deliverables:
· Initialisation report - synthesis of existing information regarding ecosystem structure and function.
· Annual reports including details of sampling programme, compilation of data collected and brief interpretation of the significance of observed changes.
· Input into final baseline monitoring report

Avifauna monitoring
The Avian Demography Unit at the University of Cape Town compiles waterbird count data for the Berg River estuary and floodplain twice annually (mid-winter and mid-summer of each year). These data, as well as all historic count data for the estuary will be purchased from the ADU and analysed by the avian specialist on the project. Attempts will be made to link changes in water bird numbers, diversity and habitat use to changes in the physio-chemical characteristics of the river and estuary.

Deliverables:
· Initialisation report - synthesis of existing information regarding ecosystem structure and function.
· Annual reports including details of sampling programme, compilation of data collected and brief interpretation of the significance of observed changes.
· Input into final baseline monitoring report