SEARCHING FOR SANDFISH IN THE TANKWA KAROO
Dr Oliver Cowan, Conservation Scientist, EWT Conservation Science Unit
OliverC@ewt.org.za
An important part of the EWT Conservation Science Unit’s (CSU) project to map and model the distribution of animal species of conservation concern in South Africa is to fill key knowledge gaps. These gaps are identified after consultations with taxon-specific experts – an example of this is a workshop we held with freshwater fish experts from CapeNature and the Freshwater Research Centre (FRC) last year. A key outcome of this workshop was the potential for new populations of the Clanwilliam Sandfish to be found in the relatively unexplored Tankwa River.
Historically, the Sandfish was widespread throughout the Olifants-Doring River System but sadly, like many of our endemic freshwater fishes, it is now Endangered. Sandfish populations have been decimated by the introduction of predatory alien fish, such as bass, and changes to river flow. These reduced numbers are currently fragmented within the Doring River and its tributaries with potentially only a single viable, growing population remaining.
The neighbouring Tankwa River was previously not considered viable habitat as it is non-perennial, drying up during the hot summer months. However, scientists at the FRC had noted on satellite imagery what appeared to be permanent pools dotted along the otherwise dry riverbed. They thought the pools may provide refugia for Sandfish, a haven from the dangers rampant throughout the catchment. Armed with this information, researchers from the CSU and the FRC set out to hunt for Sandfish in the Tankwa in December 2019.
As one drives out of Ceres, one quickly says goodbye to cell signal and tarred roads. The Tankwa at this time of year is a harsh environment and it did not help that it was in the midst of a record-breaking drought. We had been warned, when applying for research permits, of the situation but were unprepared for the sight that met us at Oudebaaskraal Dam in the Tankwa Karoo National Park. What had once been the largest dam in the region was now bone-dry, flamingos replaced by the occasional dust-devil. Somewhat chastened, we spent the next few days trekking around the semi-desert, attempting to locate the pools we had previously identified in air-conditioned offices back in Cape Town. With just GPS coordinates, bakkies and our feet this was no easy task, made more challenging by 40°C temperatures and an inhospitable landscape. After many false dawns we finally got lucky. Water! And water deep enough to be suitable for fish. It appeared the satellite imagery had not deceived us – in certain places, where the bedrock was exposed – groundwater pooled at the surface.
We started off with active searching: trawling our Seine nets through the pools, hoping to snare the elusive Sandfish but with no success. We found plenty of life in the form of hordes of Common Plattanas, their tadpoles, and a few freshwater crabs, but no fish. However, we weren’t too perturbed as this sampling method is imperfect – our hopes were pinned on our Fyke nets. These nets are more reliable as their set-up allows for passive capture throughout the night, extensive wings channelling fish towards concentric ring-nets from which there is no escape. The nets are quite technical to set up and require the use of the dinghy so our decision to manually inflate our aquatic steed on the first day was not in vain. We departed, optimistic about what the next day had in store.The next morning, we were in for a rude awakening. Firstly, our precious dinghy which we had carefully placed on the bank, comforted by the knowledge that it was safe from potential thieves, was now a deflated yellow blob. Upon closer inspection, the valves revealed tell-tale teeth marks. For some reason, the plastic must have been irresistible to members of the local baboon troop, and for a moment we felt less bad about the baboon graveyard we had chanced upon earlier that week. But things were to get even worse. As we waded out to check our nets, we noticed that the final concentric ring in which we were hoping to find Sandfish was ripped and what remained was frog limbs and half-eaten tadpoles. Spoor on the riverbank confirmed our suspicions: a Cape Clawless Otter couldn’t resist the buffet he found the previous night and had swum in to gorge himself. Once satisfied, he made his escape at the expense of our net.
With tails between legs we collected what remained of our equipment and headed back to base to regroup. En route, we bumped into a farmer who bemoaned the drought, claiming that a Tankwa River tributary which once ran through his property had shrunk to a puddle. Not expecting much we went to investigate this puddle and just about convinced ourselves to drag a net through, despite its fetid appearance. Lo and behold, fish! Sure, it was not the Sandfish but rather a population of the indigenous Chubbyhead Barb, which had miraculously survived in this unlikely oasis. This species’ taxonomy is currently being revised and it is not unlikely that the DNA we extracted from this isolated sub-population proves them to be a sub-species and of substantial conservation value. As we headed back to Cape Town later that week, we didn’t consider the trip a failure. Sure, we did not find the Sandfish despite our extensive survey, but this can allow conservation efforts to focus on the regions where it is known to occur. In addition, the miraculous discovery of the Barb population showed that wildlife continues to strive for survival despite the harsh hand that the climate (and, let’s face it, humans) have dealt it.
We would like to sincerely thank the Rand Merchant Bank Foundation for generously funding this project and our collaborators at the FRC for their assistance on this fieldtrip. To stay up-to-date with their continued work regarding the conservation of the Clanwilliam Sandfish, amongst other things, please see their website (www.frcsa.org.za) or find them on Facebook: Freshwater Research Centre.
THE FIRST PAN-AFRICAN STUDY ON VULTURE MOVEMENTS
Dr Lindy Thompson, Project Coordinator: Vulture Conservation and Research, EWT Birds of Prey Programme
LindyT@ewt.org.za
Since 2016, we have been working with collaborators across Africa on a study on the movements of the critically endangered Hooded Vulture. This project was the brainchild of Dr Keith Bildstein, a world expert on raptor migration, and previous Director of Conservation Science at Hawk Mountain Sanctuary, USA. Keith brought together scientists working in The Gambia, Kenya, Botswana, Mozambique, South Africa and Ethiopia, who had tagged a total of 30 Hooded Vultures. By pooling their tracking data, these scientists were able to compare the movements of Hooded Vultures in eastern, western and southern Africa, with some very interesting results. We looked at Hooded Vulture home-range size, and whether this was affected by age, breeding season or region. Breeding season didn’t really affect Hooded Vulture home-range size much, but we found big differences between birds in different regions of Africa. Hooded Vultures in southern Africa had massive monthly home-range sizes (12,453 km²), while those in eastern Africa were much smaller (3735 km²), and Hooded Vultures in western Africa had the smallest monthly home-range sizes (only 121 km²). We believe this variation is related to how Hooded Vultures feed in different parts of their range. The birds in West Africa are a different subspecies to the Hooded Vultures we get in southern and East Africa. The northern subspecies in West Africa often feed at rubbish dumps or on scraps left by people at markets, and they can be very relaxed around people. In contrast, the southern subspecies in southern and eastern Africa feed mainly in wild areas, and they do not usually feed close to people. This means that for Hooded Vultures in West Africa, food is predictable, the birds know when and where to find it, so they do not need to spend much time travelling around in search of food, and this translates into comparatively tiny home-range sizes. Our southern African Hooded Vultures on the other hand must travel massive distances in search of food, because there is no way of knowing when or where the next carcass may be found, and this results in enormous home-ranges. We also found that younger birds have much bigger home-ranges than adults, possibly because they are exploring new areas and they aren’t yet tied down to a nest-site. Vultures’ home-ranges overlap international borders, which highlights the need for international cooperation in vulture conservation activities. Our results will be useful for conservation planners when drafting national management plans for vultures.
You can read a summary of the article here https://doi.org/10.1111/ibi.12836, or email Lindy (LindyT@ewt.org.za) to request a copy of the full article. We are grateful to all our funders, including AZA Conservation Grant Fund, Bowling for Rhinos, Denver Zoo, Detroit Zoo, GreenMatter, San Diego Zoo Global, National Geographic Society, Raptors Botswana, The Wallace Research Foundation, The Rufford Foundation, Fulbright, the Wilderness Wildlife Trust, the National Research Foundation, and Wildlife Computers Inc.
FINDING GOLD IN THE DUNES
JP Le Roux, Field Officer, EWT Drylands Conservation Programme
jeanpierrel@ewt.org.za
The Drylands Conservation Programme, with the help of Samantha Mynhardt from the University of Pretoria, will be taking on the exciting task of trying to find one of the most elusive animals in South Africa! The Van Zyl’s Golden Mole is known from only two locations, with the last found in 2003. More than 17 years later, we are on a quest to find them again.
We will be focusing on the Lambert’s Bay area, as this is where the species was last found. The habitat consists of mostly Succulent Karoo strand veld with low elevation, which is perfect for golden moles. On the first trip to do a reconnaissance of the area, we were amazed by the amount of activity, especially from a variety of moles. With the amazement came the realisation of the challenge we are undertaking. Finding Van Zyl’s Golden Mole in a minefield of mole activity is going to be difficult! We visited various farms around the Lambert’s Bay area, going from farm to farm trying to find specific activity associated with golden moles. Most of the mole activity in the area is linked to the Common Mole-rat, which excavates big mounds of soil along its main burrow. Because they live in colonies of up to 14 individuals, their activity can be quite extensive. The Mole-rat activity differs greatly from that left behind by the much smaller golden moles. Golden moles are solitary animals and usually dig their tunnels just below the soil surface (5-10cm deep). The activity mostly consists of a foraging trail extending out from a central point around vegetation. Some areas indicated much more activity, where it was possible to identify specific behaviour along foraging trails such as head dipping. Along with the physical signs indicating that there are golden moles in the area, other promising signs such as the presence of prey items were also found. All these findings show that there are definitely golden moles in the area, but the question still remains whether they are Van Zyl’s or one of the other mole species.
The activities of different golden mole species are relatively similar, which highlights the need for creative ideas to determine the presence of this specific species. Techniques such as scent detection, thermal imaging, and testing the soil for environmental DNA (DNA that is collected from environmental samples, such as soil, rather than from an individual organism) will be some of our methods to attempt to determine the presence of Van Zyl’s Golden Moles. If these techniques prove to be successful, it will be seen as a rediscovery of the species and will greatly benefit the conservation of the species. Golden moles face many challenges, with the main threats to the species linked to habitat loss from activities such as poor farm / land management and mining.The team’s first survey will take place in the next few months, and the progress of the project will be presented in follow up articles in Conservation Matters. So, watch this space!
Thanks to Global Wildlife Conservation, for making this project possible through their Lost Species Initiative.
THE TABLE MOUNTAIN FRESHWATER ECOSYSTEMS PROJECT – ONE YEAR ON
Joshua Weeber, Table Mountain Project Intern. EWT Threatened Amphibian Programme
joshuaw@ewt.org.za
The Table Mountain Freshwater Ecosystems Project has had an exciting first year, setting a strong foundation of data collection and crucial partnerships that will allow the project to continue to evolve in 2020. It has been a year filled with new discoveries, long but exciting days in the field, slightly longer days in the office and many meetings, presentations and interesting discussions in between.
While the majority of the work has centred around the iconic and Critically Endangered Table Mountain Ghost Frog, there has also been considerable work done on the threatened freshwater ecosystem that supports this species (and many others). The project began with a flurry of activity in January 2019, a race against the onset of the Cape Town winter to install permanent temperature loggers in nine streams, design and implement detailed habitat assessments, and identify key sites to monitor Table Mountain Ghost Frog tadpole occupancy, movement and habitat preference. All before the winter storms arrived to transform these tranquil headwater streams into gushing, unpredictable torrents. For the tadpoles, this dynamic seasonal change is something they are perfectly suited to deal with, utilising their elongate sucker mouths to anchor beneath boulders and cobbles during periods of strong flow. The project is beginning to reveal just how crucial this sub-cobble habitat is for these sensitive amphibians; areas of the stream that are impacted by sediments and silt or choked by invasive Australian Blackwood rarely hold ghost frog tadpoles. In contrast, pools and riffles with deep cobbled sections, uneroded banks and indigenous riparian vegetation hold a surprising abundance of these unique animals.
Unfortunately, many of the threats evident within this freshwater ecosystem directly impact tadpole habitat. Manipulation of flow from dams and weirs, invasive vegetation and erosion as a result of path use negatively affect stream health, changing the habitat structure of these sensitive streams. Detailed surveys over the last year have produced maps that identify the location and extent of each threat and together with extensive occupancy and habitat data are enabling the team, for the first time, to quantify the impacts of these threats to ghost frog habitat. This is a crucial step towards identifying and implementing conservation interventions and feeding this into park management decisions. The first year of the project was brought to an end with a stakeholder workshop to discuss the Table Mountain Ghost Frog Action Plan, a document that aims to galvanize research, management and awareness efforts together with all project partners to achieve a future with healthy, stable freshwater ecosystems.
A key management intervention – the removal of large clumps of Australian Blackwood in Disa Gorge – is scheduled to begin in April 2020. The team are also developing a ‘Citizen Assist’ follow up plan to provide support to Working on Fire during future clearing follow ups. Discussions are also ongoing with SANParks to address erosion issues in key habitat areas, potentially through the installations of boardwalks.
Given the novel nature of this research (almost nothing is known about the ghost frog’s biology or life history), a number of new and interesting findings have emerged during the first year. It was established that tadpoles have no upper elevation limit, occurring right at the top of the mountain (850 m above sea level) in suitable habitat. Their lower elevation limit appears to be a function of slope with tadpoles disappearing from pools when streams begin to flatten out slightly at around 250 m above sea level. The distribution of the species has also been extended to the southwest by roughly 10% with a citizen observation. This amazing record sparked a search of the kloof and confirmed the presence of ghost frogs in several pools, bringing the total number of streams in which the species occurs to eight!
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The first ever record of Table Mountain Ghost Frog eggs was made when 47 white-centred eggs were found in a still, shallow pond in late December. The eggs developed into tiny tadpoles just before an out of season storm swept them away. Insights into where these tadpoles spend their time and how long they remain tadpoles for were also made this past year. A pilot Visible Implant Elastomer (VIE) study showed that, in one section of a stream, tadpoles did not move between pools over several weeks of monitoring. This method also confirmed the widely accepted view that ghost frog tadpoles take several months to reach metamorphosis – a tagged tadpole was discovered in the same pool 10 months after the initial tagging event. Although the team has not as yet managed to record in situ calls, they have made amazing progress in identifying appropriate adult frog habitat, locating over 20 fully grown Table Mountain Ghost Frogs in the first year. This relatively high detection rate (for such a rare and elusive species) provides exciting new research opportunities such as individual identification through dorsal patterning and insights into adult range size and life span.
2020 has already got off to a frantic start with the summer fieldwork season commencing in February. It will be exciting to assess the presence of tadpoles, location of adult frogs and the integrity of the stream environment in relation to last year’s data. May 2020 prove to be another solid step towards ensuring the survival of this unique frog, and more importantly the freshwater ecosystem it relies upon, into the future.
This work is made possible by the Table Mountain Fund and done in collaboration with SANParks, SANBI, CapeNature, and UCT.
FODDER GROWING PUTS A SMILE ON THE FACES OF WOMEN, SAVES RUGEZI MARSH IN RWANDA
Adalbert Aine-omucunguzi, East Africa Regional Manager, and Daniel Munana, Rwanda Field Coordinator, EWT African Crane Conservation Programme (EWT/ICF Partnership)
AldabertA@ewt.org.za and DanielM@ewt.org.za
In Rwanda, like many other developing countries, women are predominantly responsible for management and conservation of resources for their families. They spend vast amounts of time collecting water, fuel wood, food and fodder, and managing crop fields and livestock. Women are also the primary caregivers to children, the elderly and the sick, in addition to ensuring a clean environment around homes. Their traditional and generational knowledge of biodiversity supplies communities with medicines and nutritional balance. As a result of this relationship with nature, women have, over time, acquired knowledge of the land/soil conditions, water, wetlands, and forest resources as well as other environmental features.
Our project in Rwanda has taken advantage of women’s relationship with nature to empower them to grow fodder and reduce vegetation harvesting pressure on Rugezi Marsh. This followed a realisation that women and children were walking long distances on steep slopes and spending many hours harvesting vegetation from Rugezi Marsh to feed livestock. This was in addition to their routine heavy domestic chores. To address this plight of women, as well as reduce pressure on Rugezi Marsh, our project promoted the growing of Napier Grass to provide fodder. We conducted sensitisation campaigns that targeted both men and women, but in the end, women showed a greater interest in the programme. Most of the men confessed that they had allowed or asked their wives to engage in the fodder growing programme. This was not surprising because fodder collection and livestock feeding under a zero grazing system is the responsibility of women.
We provided Napier Grass seedlings to 559 households and provided training on its management. Two years down the road, women from some of these households could not hide their delight when asked how fodder growing has helped them. Below are examples of what they had to say:
Uwiragiye Chantal from Rusarabuye Sector: “Fodder growing saved my time. I used to spend two to three hours in the marsh harvesting grass, but for now, I have it at the comfort of my home. Our animals are well fed because we have enough fodder for them. Rugezi Marsh will recover because we have stopped harvesting grass from it.”
Uzabakiriho Jeannette from Butaro Sector: “I am very happy that the project gave us fodder. My life and that of my family has changed since we started producing fodder on our farm. Feeding my animals has become easy and less time consuming. As a result of feeding animals well, we have more milk for our children and a surplus for sale. We now have more income from milk compared to when we had to gather grass from Rugezi.”
Nyambere Celine from Rusarabuye Sector: “My family is no longer in conflict with neighbours and local leaders. In the past we used to illegally harvest grass from Rugezi, and the local leaders would run after us. At times our hungry animals would escape into our neighbours’ gardens. All this used to generate conflict, but now we are free and my animals feed well. The whole community has benefited because we are giving planting materials to other community members. Some people come to visit our gardens to learn how to grow Napier Grass.”
Ngendahimana Dative from Ruhunde sector: “My children and I no longer move long distances to harvest grass from Rugezi Marsh. We are able to feed our animals using home grown fodder and they are healthy. They are giving more milk, some of which we sell. “
These testimonies are evidence that fodder growing has relieved women of the burden of walking long distances to harvest it from Rugezi Marsh. It has reduced their daily workload and put a smile on their faces.
This work is made possible by the MacArthur Foundation and the Critical Ecosystem Partnership Fund (CEPF).
HABITAT STUDY HELPS SOLVE THE PUZZLE
Bonnie Schumann, Nama Karoo Coordinator, EWT Drylands Conservation Programme
BonnieS@ewt.org.za
The EWT’s Drylands Conservation Programme recently joined forces with Dr Sue Milton, Karoo ecologist and botanist, to characterise Riverine Rabbit habitat in the Succulent Karoo and Renosterveld. Our aim is to understand the exact habitat requirements of Riverine Rabbits in the southern- and eastern populations.
Most of the past work done on Riverine Rabbit ecology and habitat was carried out in the northern population of rabbits, which were first described and documented in the Nama Karoo in 1901. This region has been the focus of much of the research and conservation efforts to date. As such we have a pretty good understanding of rabbit behaviour and habitat requirements here. Our understanding of the southern population, in the Succulent Karoo, is less comprehensive. This is due to the fact that Riverine Rabbits were only discovered in the Succulent Karoo in 2003. Incredibly, a third eastern population remained undetected in the western Baviaanskloof area until 2018. To understand these populations better, camera trap surveys were carried out near Touwsriver and in the Baviaanskloof, yielding excellent results in terms of detecting Riverine Rabbits.
We revisited these locations in in September (spring) to describe the plant communities in the vicinity of the cameras where rabbits were detected. Plant species, the height and cover of the vegetation were recorded, as well as other factors such as slope aspect, soil type and depth and distance to nearest riparian areas. The results of this work will narrow down future search areas and assist us to identify corridors between known populations. Understanding what ideal habitat looks like will also inform how best to manage known distribution areas to maintain existing populations.
Many thanks to Dr Sue Milton (RenuKaroo) and Liesl Eichenber (Ecologist on Sanbona Nature Reserve), for their assistance and helping to complete the Riverine Rabbit puzzle.
The work was made possible with funding from Rand Merchant Bank and the Zoological Society for the Conservation of Species and Populations (ZGAP).
