Download Aquatic invertebrates training report UNESCO CoEB

TRAINING REPORT ON AQUATIC INVERTEBRATES
(Draft)
Introduction
This training has been offered under the UN’s mission in Rwanda aimed to develop scientific
capacity in the country and specifically to develop a center of excellence in biodiversity
conservation where several scientists of CoEB nodes and other Government institutions were
equipped with skills in aquatic invertebrates, stream habitat description and measurements of
factors that influence their distribution.
The training took place from 27th August to 2nd September 2012 at the National University of
Rwanda’s Zoology department laboratory and in various fields of the country. The training
composed by classroom lectures, field visits, samples identification, and data /samples analysis.
The training had the following objectives: Train scientists in different methods of sampling
aquatic insects and preserving them as vouchers for future reference, Develop the capacity of
trainees in aquatic invertebrate identification at least to Family level of identification, To
develop an understanding of the ecological relationships between aquatic insects and their
environment and Train scientists in data analysis techniques to be able to develop metrics for
water quality assessments at different sites.
After classroom lectures, trainees started the field visits where they visited various fields such
as: Nyabugogo site, Mwogo site, Bugesera/Kamatana reservoir, Bugesera/Rumila lake,
Akagera floodplain wetland, and Songa/ ISAR.
Nyabugogo site: This site was sampled at 12h30. It is a river with .Widith: 6.95m, depth on one
edge 29cm and depth on other edge 76cm. This river is covered by the vegetation and
degraded by the urbanisation.
Mwogo wetland site: This wetland was sampled at 08h30. It has a depth of 45cm and the
water was blackish due to decomposition processes and covered by Azolafilucolloides.
It is surrounded by Cyperus papyrus, Cyperus spp. The sampled habitat was in pool at the edge
of a wetland, up stream of which is agricultural activity.
Bugesera/ Kamatana reservoir: This site was sampled at 10h15 with the depth on the edge of
52cm. It is an open area surrounded by Cyperuspapyrus ,Cyperuslatifolium.
The sampled site is water reservoir constructed to serve the surrounding communities. The
reservoir has high biodiversity value as evidenced from several water fowls seen at the site.
Bugesera/Rumila Lake: This lake was sampled at 04h00 p.m. This lack is dominated by human
activities (cultivation of beans and La pallisehoter) where cultivation area is up to the lake
shores. As a consequence, almost no buffer is available to protect the lake from pollution
sources
Akagerafloodplain wetland: This wetland has 1.95m of width and it was modified by human
activities. It is dominated by by Cyperuslatifolium, and Eichhorniacrassipes and slow flowing.
The sampled site is located within the Akagera river floodplain and is impacted variously by
human activities such as agriculture and road networks.
Songa/ISAR: This site has 30cm and 0.8m of depth and width respectively. It was sampled at
04h30 p.m after some rains the bottom is sandy. The site is covered by Phragmites, Pennisetum
spp ,Cyperus latifolium, Ludwigia abyssinica and water colour was milky because of clay soils in
the area. The site is located in a rural area and the main land use type is cattle grazing and as
such the water may be impacted by deposition of wastes including cattle dung and other
chemicals used in cattle spraying.
Physicochemical measurements: During this training, different physicochemical parameters
that may influence aquatic invertebrate diversity were introduced to the trainees. Trainees
were tough how to handle and prepare various equipment to measure different variables such
as River width (m), River/pond depth, Flow speed, Electrical conductivity (µS), Total Dissolved
Solids (TDS), PH, Turbidity (NTU), and Dissolved oxygen.
Participant measuring dissolved oxygen at a site
Aquatic insect sampling
Aquatic insects sampling in the field was demonstrated using two methods (standing water
(lentic) and flowing water (lotic)). The D-frame (Dipnet) was demonstrated for use in non
wadeable and very deep waters.
The sampled species were cleared of debris by rinsing in clean water and aquatic insects sorted
out of the debris using forceps and preserved in 10% formalin thereafter, the collected
specimens were labeled where date, bottom type, and name of collectors were highlighted.
Trainees sorting samples in the field
In the laboratory
The trainees were explained more about how water bodies function, differences between rivers and
lakes in terms of habitat and functioning.
The importance of aquatic insects as indicators of water quality was demonstrated using the
different tolerance categories from the very tolerant taxa such as Oligochaetes and blood worms
(Chironomidae) found in poor quality water to the highly sensitive taxa such as the mayflies
(Ephemeroptera), stone flies (Plecoptera) and cadisflies (Tricoptera) found in pristine habitat with
good quality water.
Aquatic invertebrate identification
Aquatic invertebrate taxonomy was introduced to the trainees using samples collected from
the field. Trainees sorted invertebrate groups based on their morphological characteristics such
as body shape, type of mouth parts and possession of and number of legs and wings and then
they identified them by using the field guide to aquatic insects of Southern Africa (Geber and
Gabriel 2002).
Data analysis
Data analysis was done by using Microsoft excel. Total number (taxa richness) for each site was
then determined and diversity indices calculated for each sites using Species Diversity and
Richness (SDR 4) package. Cluster analysis was also used to determine similarities in taxa
composition among the sites sampled.
Results/interpretations
A total of 18 invertebrate families were identified with certainty by the trainees. Most of the
invertebrates identified were of tolerant category implying that most of the sites were of poor
water quality and generally degraded.
The highest dissolved oxygen value was recorded at Nyabugogo stream where water was fast
flowing compared to the other sampled sites. Intermediate dissolved oxygen levels were recorded
at the reservoir and lake sites where photosynthetic activity by macrophytes and
phytoplanktonmay be responsible for the relatively high oxygen levels.
Turbidity was lowest at Kamatana reservoir and highest at Nyabugogo stream. In terms of domestic
use of the water at sampled sites, the Nyamatana water would be ideal for human use with minimal
treatment costs while the Nyabugogo water would be the most expensive to treat before it becomes
usable by humans.
Songa site presented a high taxa richness and a low tolerance and also a rich water quality
while Kamatana showed a high variation in Shannon’s diversity index.
Recommendations
Establishment of a well equipped aquatic sciences laboratory (equipments & books)
Introduction of bachelor’s degree in aquatic sciences to include aquatic biodiversity
conservation
If logistically feasible sampling of aquatic insects should also be carried out in pristine
conditions such as in streams and rivers located within National parks in Rwanda as diversity
would be extremely high there
Conclusion
The training will impart practical skills to the trainees on how to identify aquatic invertebrates
and be able to relate the findings to the quality of water resources in the studied rivers. The
trainees are expected to be trainers of other people within the country and through a multiplier
effect create a critical mass of aquatic invertebrate expertise in the country.