The AquaRAP team reached our final camp, south of Chief's Island, after a 20-minute hop by prop plane. As we traveled, I scanned the land below for giraffes – the only large African mammal I haven't yet crossed off my "must-see" list. No luck, although the habitat is right: open savannah dotted by trees and water sources. Water is not always so plentiful. This part of the Delta is seasonally flooded, and later in the year, many of these pools and swamps will dry up completely. The organisms that rely on it will either move on or perish.
|Mokoros, or traditional handcarved canoes, wait |
along the shore.
The AquaRAP fish team couldn't wait to begin sampling in this unique area. Soon after we arrived, we got into mokoros – traditional, handcarved canoes – and were taken by local guides to a promising spot behind our camp.
Motorized boats aren't allowed here, so the mokoros are our mode of transport for the next four days, presenting some challenges to our collecting efforts. Fish team members lean over the sides of the mokoro – carefully, to avoid tipping the shallow boat – and install their net, while the rest of the team gets the hang of balancing.
|Budzanani Tacheba and the rest of the |
team prepare for the first journey in
TOOLS: Describing a new fish species.
ISSUES: Tourism: Pros and Cons.
SPECIES: Aquatic birds of the Delta.
PEOPLE: Paul Skelton, South Africa's Fish Man.
On our second day here, we experienced something out of the ordinary: rain. It hasn't rained here in June for at least a decade, according to one of the locals. In fact, rain has been a topic of conversation throughout the trip.
Due to heavy rains earlier in the year, we're seeing much higher water levels in this area than we would have normally. These rains have resulted in heavy vegetation, and the birds, and probably many other animals, are flourishing (see the Species section for more). We couldn't have chosen a better time to visit this amazing place.
– Reported by Clare Nielsen
AquaRAP in Action: A Floristic Picture of the Delta
Gliding by mokoro through a forest of sticky hippo grass, I noticed the diversity of plant life floating in the crystal clear water beneath us. These traditional dugout canoes are the best way to get an intimate look at the surrounding aquatic system.
We have reached the final site of our expedition, and I used this lazy ride through the river channel to talk with aquatic plant expert, Fred Ellery, about his observations during the trip. By describing the variation in plant life throughout the distinct research sites, he created a floristic picture of Delta.
|Hippo Grass, Vossia cuspidata.|
Like connecting the stars of a celestial constellation, the independent research sites start to form an intertwined landscape. Fred's descriptions first take us back to the Upper Panhandle where the expedition began. In this area, high loads of sediment are rapidly flowing into the water catchment. The river has to cope with these large sediment loads which are being pushed into the river banks. This is what causes the main channel to meander.
The result of these ongoing processes is a minimal diversity of habitats, lacking lagoons and islands of lush sausage and jackal berry trees. Instead, the landscape is mainly flattened floodplains with a limited variety of plant species. The dominant plants found here are Echinochloa grasses, Vossia cuspidata or hippo grass, and a type of river reed known as Phragmites sp.
Continuing down the channel of the Delta, we return to Guma Lagoon. Here the sediment has filtered out of the water. Little
oxygen is present in the water, slowly choking the dying system. However, unlike the lack of fish in these harsh conditions, the plants are able to adapt. There exists a full range of habitat types here, including islands and lagoons, and a greater plant diversity in the seasonal flood plains. The dominant plants in the area are Miscanthus junceus
or the tall swamp savanna grass, Phragmites australis
, and beds of Cyperus papyrus
, which look like delicate fans waving in the breeze. Hippo grass, common throughout the Upper Panhandle, cannot be seen in this lagoon.
Back at Xakanaxa, the water supply is gradually decreasing, and the fluctuation in the water level is limited to about 1.5 meters. Here, a damming effect is taking place on the meandering ridge, creating a variety of habitat types such as cut-off ox bow lakes, islands, and numerous types of lagoons. Since the system is relatively new – flooding as recently as 80 years ago – the plant communities are in an early succession phase. Therefore, the dominant species found here are Pycreus sp. in the back swamps, sedges, and swamp savanna grass in localized areas.
|Fred and Budzanani |
Returning to the lower fringes of the Delta, we stop at the first sample site. Though we have just begun gathering information, Fred has already observed some obvious distinctions between this and the other sites. We are now located on the border between permanent flooded areas and seasonally flooded grasslands. This intermediary zone creates a unique arrangement of habitat and species known to occur in both types of regions.
Floristically, the area is very rich. This is due to the seasonal water fluctuation, drowning out plant life at certain times of the year. The subsequent decomposition process releases nutrients into the water, encouraging new growth. Though plant diversity is high, there lacks a clear presence of any dominant species. All the species tend to be observed in equal quantities.
|Water Lily, Nymphaea nouchali|
I found the area to be particularly attractive due to the immense covering of water lilies on the surface of the water. Two types of lilies can be found here, including the nymphaea lotus or night water lily in deep pools of water, and the nymphaea nouchali which is common in shallow conditions. It amazes me how subtle differences in the soil conditions can affects the color of the lilies. A range of hues, from soft pink to powder white to deep violet, is dispersed throughout the floodplains.
As we turned back to Oddballs camp for the evening, team leader Pete Ashton showed me how to use the stem of a water lily as a straw. Now I can quench my thirst without risking any encounter with an opportunistic crocodile. I sip the sweet water and reflect on the beauty of the area. I believe there must have been an ulterior motive for choosing this last research site. It has made an imprint on the minds of all of us, ensuring that after the expedition we will be sure to return again.
– Reported by Sharon Safran
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