Biodiversity

[Lisbeth]

Swap salmon for sardines to keep four million tonnes of fish in the sea

March 1, 2022 | David Willer
Henslow Research Fellow, Sustainable Seafood, University of Cambridge

Cutting down on meat and dairy is one way to make your diet better for the planet. But when it comes to sustainable seafood, buying sardines instead of salmon for your sandwiches and salads should be your first port of call.

A third of fish stocks are being harvested at rates that exceed what these populations can replenish, and 90% are fished right up to their sustainable limit, according to the UN Food and Agriculture Organization. A leading cause of overfishing is, ironically, the demand for fish feed. Over one-third of all fish caught worldwide are fed to farmed animals instead of people. Fish farming, or aquaculture, is the world’s fastest growing food sector. Most of the Atlantic salmon sold in supermarkets in the UK is farmed.

Rearing these large, predatory fish involves feeding them a diet rich in omega-3 fatty acids and protein, nutrients that are also essential to humans for brain development and nerve function. In a new study, my colleagues and I found that if people ate the wild-caught fish, such as sardines, which are usually destined for salmon farms, it would leave nearly 4 million tonnes of fish in the sea and provide an extra 6 million tonnes of seafood.

Feed people, not fish farms

The sea provides humanity with a bounty of nutrient-rich food, which we have benefited from for thousands of years. Seafood is one of the most easily absorbed sources of key nutrients such as omega-3 and vitamins D and A that humans need. It is believed that a diet that included seafood may have helped humans develop bigger brains. There is a global responsibility to sustainably use this resource, as over 3.3 billion people rely on it as their source of animal protein.

Salmon raised in coastal farms off Scotland is the UK’s largest food export by total annual economic value (followed by bread and pastries). Our research team carried out a thorough assessment of the Scottish salmon industry, collecting data on fish nutrient content, fishmeal and fish oil composition and examining the transfer of micronutrients from feed to fish.


A circular pen containing swimming fish seen from above.
Coastal salmon farms produce a lot of effluent pollution. Russ Heinl/Shutterstock

We found that by removing wild-caught fish from salmon feed and only using fish byproducts instead – such as trimmings and offcuts from the filleting of farmed fish – 3.7 million tonnes of fish could be left in the sea and global annual seafood production could increase by 6.1 million tonnes. Over half of the essential dietary minerals and fatty acids available in wild fish are currently lost to human mouths when these fish are fed to farmed salmon.

By comparing salmon with other options, our research also highlighted the health and environmental benefits of eating more sustainably farmed seafood, such as mussels. Mussels belong to the bivalve class of molluscs that include shellfish like clams and oysters (but not prawns, lobsters or crabs). Our research has shown that mussels are one of the most sustainable foods on the planet, more so than any other meat, fish, and most land-based crops like soya, wheat and rice.

Mussels require no feed, they simply eat algae in the water. The reefs they create act as nurseries where young fish can develop to full size, helping to regenerate wild fish stocks. Bivalve farms use up no land and no freshwater. They actually act as a carbon sink.


A crab rests on an underwater rope covered in mussels.
Mussel farms can provide habitat for other species. A Daily Odyssey/Shutterstock

But what if you like eating salmon? The use of alternative feeds in salmon farms is growing, but some are better than others. Feeds made from crops like soya and corn need a lot of land and water to produce, but those made using algae are richer in omega-3 and use up sea space (of which there is plenty) instead of land. We need more research and investment to produce nutritious seafood while reducing pressure on marine ecosystems.

If you’re ever unsure, there are two simple mnemonics to guide what fish you should buy:

ECOME - Eat clams, oysters and mussels everywhere

SMASH - Sardines, mackerel, anchovies, sprats and herring

So enjoy your moules frites and barbecued sardines. Eat small, oily fish and bivalve shellfish. Eating more of these tasty foods, and foregoing the salmon and tinned tuna, can make a real difference to the ocean.

[Lisbeth]

Biodiversity is in crisis worldwide and time is running out


(Photos: Unsplash / Douglas Bagg / Joshua Cotten / Vincent Van Zalinge / Sebastian Lambarri / Mike Marrah / Peter Burdon)

By Ken Mwathe | 29 Jun 2022

Tackling biodiversity loss requires ambitious political leadership and will from countries. Without this, the world stares into a bleak future.
_______________________________________________________________________________________________________________________
Nature is at a tipping point. Over the past century, human activities have destroyed nature at an alarming rate. The 2019 Global Assessment Report on Biodiversity and Ecosystem Services highlighted that around one million animal and plant species are at risk of extinction, underlining the precarious situation we humans find ourselves in.

It is a serious indictment on the global community that the Aichi Biodiversity Targets — an ambitious set of global goals aimed at protecting and conserving global biodiversity by 2020 — were not achieved. In the past three years, the focus of governments and non-government stakeholders has been to craft a new framework to save nature in the next decade.

Dubbed the Post-2020 Global Biodiversity Framework (GBF), the new plan is being negotiated — through a series of working groups and technical consultations — with a view to getting it finalised and endorsed during the 15th Meeting of the Conference of the Parties (COP) to the Convention on Biological Diversity, scheduled for December 2022 in Montreal, Canada (COP15).

Catastrophic failure
The fourth Open Ended Working Group (OEWG 4) held in Nairobi, Kenya, last week has catastrophically failed to agree on text for a new deal for nature.

Government delegations came to Nairobi to agree, among other things, on targets to save species, ensure robust and well-connected ecosystems, include the rights of indigenous peoples and local communities as well as a financing mechanism for implementation.


Delegates during the closing of the 15th Conference of the Parties (COP) of the United Nations Convention to Combat Desertification (UNCCD) in Abidjan, Ivory Coast, 20 May 2022. (Photo: EPA-EFE / Legnan Koula)
However, whereas some progress was made in Nairobi, it was painfully slow across the whole framework, three years after the first working group meeting was held in Nairobi in August 2019.

Also notable is the fact that most of the GBF text across the mission, goals and targets was left in square brackets, signalling a deep lack of consensus among government negotiators in Nairobi. This means that there is still a lot of work for the parties and stakeholders ahead of Montreal to “lift the brackets”, as many civil society organisations are now calling for.

COP15 Montreal

Ahead of COP15 in Montreal, nothing short of high-level political intervention will unlock the deadlock, which — in one part — is driven by countries looking only at their national interests, rather than the good of nature and humanity.

We call upon world leaders to prioritise nature and push for an ambitious deal at COP15. Anything short of that will be disastrous since the biodiversity crisis is linked to the climate crisis.

As Melanie Heath, BirdLife’s Director for Science Policy and Information notes, “there are five months to COP15 and momentum has to build dramatically — everyone must feel the heat and act and inject a sense of urgency and all government leaders must place much greater attention and priority on the negotiations to work.

“There is no doubt that this is a critical moment for nature, where inaction will have serious implications on the future of humanity.

“While the world’s attention is on the impacts of climate change, it is critically important that world leaders and the global community realise that climate and the biodiversity crisis are inextricably linked — nature is impacted by climate change, but is also part of the solution.”

Species loss

An ambitious GBF should address species loss and address factors that drive species towards extinction. Second, there is a need to put in place a GBF that places emphasis on expanding and effectively managing protected and conserved areas. This should be coupled with holistic spatial planning and ensuring connectivity.

For this purpose, the role of Key Biodiversity Areas as a global standard for identifying conservation priorities should be recognised. Linked to this is the critical role of indigenous people and local communities (IPLCs) who number about 476 million people — about 6% of the global population, but inhabit about 85% of areas proposed for biodiversity conservation.

IPLCs are critical partners in helping achieve protection of 30% of the planet’s land and ocean areas by 2030.

Working with partners including local communities through its “local to global” partnership model, BirdLife has achieved significant conservation successes and thus the consensus at the Nairobi meeting on acknowledging the critical role played by IPLCs is commendable.

Finally, the means of implementation are critical for effective implementation of the GBF. This includes a clear monitoring and reporting framework.

Critically, predictable financing must be made available to implement the GBF. Africa faces a huge shortfall in financing biodiversity conservation estimated at about $700-billion annually, thus addressing how to finance this gap is imperative.


White-fronted plovers’ numbers are down on this Plettenberg Bay beach. Dogs and foot-traffic present unintended yet major challenges to the beach’s biodiversity. (Photo: Angus Begg)

Political support from countries is also key. Tackling biodiversity loss requires ambitious political leadership and will from countries, without which the world stares into a bleak future.

With the missed opportunity in Nairobi, a robust commitment is urgently needed ahead of Montreal.

Time is ticking.

As parties and stakeholders spend time in plenary halls debating a word here and a bracket there, the next species is slowly being pushed towards extinction.

Only a bold commitment through an ambitious GBF will reverse this and put the world on a nature-positive trajectory.

The next five months are going to be critical in starting the journey to achieve this. DM/OBP

Ken Mwathe is the Policy and Communications Coordinator, BirdLife International Africa Office, Nairobi.

[Richprins]

[Lisbeth]

South Africa’s global biodiversity ranks as nothing too special


Red macau in brazil. (Photo:The Swiftest report)

By Don Pinnock | 13 Sep 2022

Biodiversity is fundamental to human wellbeing and a healthy planet, but it’s deteriorating worldwide. So how is South Africa shaping up compared to the rest of the world?
________________________________________________________________________________________________________________________
South Africa’s Draft White Paper on the Sustainable Use of Biodiversity begins with an assumption that we’re one of the most biodiverse countries in the world. But we’re not as biologically endowed as we think.

A report just released by US risk analyst Matthew Nash – The 200 Most and Least Biodiverse Countries in 2022 – places South Africa way below Brazil, but also shows we’re a lot less diverse than Indonesia, Colombia, China, Mexico, Australia, India, the US, Tanzania or the DRC. The ratings include birds, mammals, fish, amphibians, reptiles and plants.


From the 200 Most and Least Biodiverse Countries in 2022 – The Swiftest Report

Over the past century, says the report – issued by the data company Swiftest – the world has seen an unprecedented decline in biodiversity, triggered by climate change, habitat loss, overexploitation, pollution and pesticides. This prompted Nash’s team to take a deep dive into how nations rank in terms of biodiversity, using all available sources.

It was a difficult exercise. “Many countries have conflicting data reports, under-reporting, or simply lack reporting when it comes to the various species,” Nash writes. “Additionally, new species are being identified yearly, and others are dying out at alarming rates.”


Tiger-leg monkey frog. (Photo:The Swiftest report)

Most biodiverse, most populated

An interesting observation was that some of the most biodiverse countries are also the most populated, while many other extremely biodiverse countries are spending the least on conservation.

Brazil is an example of the latter. It tops the list as the most megadiverse place on Earth, with 1,816 bird species, 1,141 amphibians, 4,738 fish, 693 mammals, 847 reptiles and 34,387 plant species. However it permits massive destruction of its precious rainforest, home to an estimated 20% of the world’s total biodiversity, with new native species being discovered all the time.

Countries with the lowest biodiversity are, understandably, extremely small ones, or island states such as San Marino, Monaco, Kiribati, Luxemburg and the Comoros, as well as mostly frozen countries such as Iceland. Surprisingly, no African country features in the top five of any of the six species categories.

Australia tops the list of reptiles (1,131) and fish (4,992) species, while Indonesia has the greatest variety of mammals (729). However, the Amazon puts Brazil ahead on plant species (34,387), followed by China (31,362).


A toucan on a branch in Colombia. (Photo:The Swiftest report)

By comparison, South Africa has 762 birds, 132 amphibians, 2,094 fish, 331 mammals, 421 reptiles and 21,250 plants.

The biggest threats to biodiversity, says the report, are rising global temperatures, habitat loss, overexploitation and pollution. According to the WWF, the loss of species we are experiencing today is somewhere between 1,000 and 10,000 times greater than the natural extinction rate.

“While we don’t know exactly how many species of plants and animals are out there, a low estimate is that we could be losing 200 to 2,000 species every year, while a high estimate is between 10,000 and 100,000.”


Deforestation of the Amazon rainforest in Brazil. (Photo:The Swiftest report)

Research has shown that the degeneration of wildlife could lead to more disease outbreaks. As humans travel deeper into nature, we increase our risk of exposure to pathogens carried by wild animals. Many recent viral disease outbreaks can be traced back to wildlife.

In general, biodiversity is ailing. In 2011, the UN Convention on Biological Diversity set 20 targets that needed to be urgently implemented by 2020 (the so-called Aichi Biodiversity Targets). These included biodiversity values being included in national and local planning, actions harmful to biodiversity being eliminated, habitat loss halved, overfishing avoided, pollution and pressure on coral reefs reduced, 10% of coastal waters protected, extinction of species halted and genetic diversity enhanced.


Clown fish in Great Barrier Reef. Photo: The Swiftest report

Only six of 20 targets

By 2020, only six goals had been partially achieved. The other 14, such as eliminating subsidies driving biodiversity loss, or halving the rate at which natural habitats are being lost, had been completely missed.

“Plant and animal species support the ecosystems we rely on,” says the Swiftest report. “They aid in pollination, soil fertility, food and medicine production, air quality and much more. Losing too many species would negatively affect the balance of our world.


An anteater in Mexico. (Photo: The Swiftest report)

“Keeping our planet biodiverse can also help slow the effects of climate change. For instance, when forests are cut down at unsustainable levels, we’re removing our natural defence against excessive carbon dioxide in our atmosphere. The Amazon has long been referred to as the ​‘lungs of the Earth’ since the incredibly diverse plant species are constantly sequestering carbon and producing oxygen.”

In another survey on the best and worst countries for animal rights, South Africa came in at 51 of 67. The top 10 countries were all in Europe. On dog-friendly countries, Italy came out tops, followed by New Zealand, France and the UK. South Africa was at 32 of 51, with Vietnam and China at the bottom. DM/OBP

[Lisbeth]

[Lisbeth]

Nasa turns its gaze from space to the Western and Eastern Cape in new biodiversity project


A new biodiversity research project, BioSCape, will link data collected from Nasa satellites and aeroplanes with field observations to better understand the biodiversity of the Greater Cape Floristic Region, impact of climate change on biodiversity, and nature’s contributions to people. (Photo: Shelley Christians)

By Kristin Engel | 26 Oct 2023

Two Nasa planes took flight from Cape Town last week as part of a project with South African scientists aimed at improving understanding of the impacts of climate change on biodiversity and to reduce biodiversity loss and threats.
_____________________________________________________________________________________________________________________
NASA technology used to study outer space is now being turned downwards towards the Western and Eastern Cape to scan one of the most unique biodiversity hotspots on the planet — the Greater Cape Floristic Region (GCFR), described as the most difficult place on Earth to study biodiversity.

The project — BioSCape — is a biodiversity survey conducted by the US National Aeronautics and Space Administration (Nasa) with several South African organisations to link satellite and airborne data with field observations to better understand the biodiversity of the GCFR and the impact of climate change on biodiversity. The project will explore the threats to biodiversity across terrestrial and aquatic systems in the region, as well as their structure, composition and function.

Last week, two modified Nasa planes — a Gulfstream III and a Gulfstream V — took off from Cape Town to begin six weeks of data collection across the GCFR for the one-of-a-kind project.


The area the Gulfstream III and Gulfstream V will scan. (Map: Supplied)

The project was at least eight years in the making by a joint team of about 150 South African and US scientists before the planes could take to the sky. Daily Maverick observed the first takeoff with the teams on Friday, 20 October.

The aim is to improve understanding of the impacts of climate change on biodiversity to develop new technologies for monitoring and managing nature’s contributions to people to reduce biodiversity loss and threats.

Woody Turner, programme scientist for Biological Diversity and programme manager for Ecological Forecasting at Nasa’s Science Mission Directorate, oversees Nasa’s research efforts to use satellite-derived information to understand the relationship of biodiversity to climate and landscape change and ecosystem function.

‘Our life-support system’

Turner told Daily Maverick that biodiversity underpins our lives and how we function as a species; it cleans the air, purifies water and provides an abundance of food, clothing material, materials we build from, medicines and so much more.

“That’s our life-support system,” Turner said. “I’d say climate change and biodiversity loss are two existential crises facing humanity today. Existential, because if we don’t fix it, if we don’t do it and get it right it can lead to our own demise, the extinction of species.

“People are very focused on climate. That’s great, but I’d say equally dire is the loss of biological diversity. This is something that may be harder for us to correct than our changing climate… Extinction is a one-way ticket, it’s a one-way loss. We can’t really fix that.”

Turner said climate change and biodiversity loss were intimately connected and just as life affected climate, climate affected life.


Scientists from South Africa and the United States have teamed up to study biodiversity in the Greater Cape Floristic Region. (Photo: Shelley Christians)

“I work for Nasa so yes, we’re trying to go to Mars and Mars is great, but living on Mars is not trivial. We evolved to live here [on Earth], so let’s take care of what we know and what we got, because this is our cradle, this is our home and where our children live. So we need to take care of it, but we can’t take care of it without understanding and taking care of the life around it,” he said.

BioSCape marine science lead Erin Hestir, from the University of California, added: “Nasa is most famous for studying space, and we all think about looking for life in other places, but the one place where we know life exists is here on planet Earth, and it’s precious because it literally defines our ability to be here. That diversity of life is what supports our livelihoods and makes planet Earth so special and unique.”

The science team consists of Jasper Slingsby, a senior lecturer in Plant Ecology and Global Change Biology at the University of Cape Town (UCT); Adam Wilson, BioScape terrestrial science lead from the University of Buffalo; Hestir; Anabelle Cardoso, BioScape science team manager from the University at Buffalo and UCT and Cherie Forbes, Applications Coordinator.

Cardoso has been a leading force in the project, coordinating all the researchers and ensuring that researchers in the field are in sync with the data collected from the aircraft.

“What’s really exciting about this project is that in a lot of ways the technology that NASA has come up with has outpaced the science, in the sense that the technology is extremely impressive and so far has been focused on looking at other planets, or like methane emissions, which are very important, but this is the first time that Nasa — or anyone really — is making a concerted effort to catch up biodiversity science with the potential of the technology,” Cardoso said.

Cardoso explained that the sensors being used – imaging spectrometers -have been used for looking at planets but now they hope this technology could be useful for monitoring ecosystems on Earth.

“What NASA is trying to do is to eventually have these sensors on satellites, imaging the whole world at regular time intervals, and what they’re interested in, is seeing if these kinds of sensors on satellites can measure biodiversity, but this is not easy to do. So before they can get to this, they run airborne campaigns, which is where they take a very similar sensor and instead of putting it on a satellite, they put it on an aeroplane and then have the aeroplane fly over imaging the area. Then we are pairing this with ground observation by all of our field scientists who are out in the field,” she said.

Unique technology

BioSCape is studying coastal and marine environments in the GCFR using airborne imaging spectroscopy, lidar and new hyperspectral data, ranging from UV to thermal wavelengths.


Holly Bender from NASA’s Jet Propulsion Laboratory and the team lead of the Portable Remote Imaging Spectrometer. Bender led the team that built this technology for the plane, which will use remote imaging to explore the marine and freshwater ecosystem distribution, structure and composition. The data for BioScape is being collected using a unique combination of four remote sensors built on the planes, each giving a different set of data. (Photo: Shelley Christians)

These remotely sensed data will combine with existing and new field observations of the spatial distribution of species, ecosystems and their characteristics. Together, these observations enable high-resolution mapping of biodiversity, functional traits and environmental variations and local disturbances (weather, human activity, land degradation, etc).

The data for BioSCape is collected using a unique combination of four remote sensors built into the two planes, each giving a different set of data that will be analysed to create the survey of the GCFR. This data will be available for all researchers once compiled and will assist with numerous research projects.


Biodiversity research project BioSCape will link data collected from Nasa satellites and aeroplanes with field observations to better understand the biodiversity of the Greater Cape Floristic Region, impact of climate change on biodiversity, and nature’s contributions to people. (Photo: Shelley Christians)

The four remote sensors are:

• AVIRIS-NG: The Airborne Visible / Infrared Imaging Spectrometer – Next Generation sensor studies interactions between climate and the health of vegetation and aquatic ecosystems. It is a whisk-broom imaging spectrometer with a spectral range of 380-2,510nm and sampling resolution of 5nm.

• HyTES: The Hyperspectral Thermal Emission Spectrometer sensor is a hyperspectral imaging spectrometer measuring thermal emission in the 7.5μm-12μm range. It provides ecosystem diversity metrics in terrestrial settings and physical marine measurements (eg, sea surface temperatures).

• LVIS: The Land, Vegetation, and Ice Sensor (LVIS) is a laser altimeter scanner able to produce 3-D images of topography and vegetation. Data from LVIS will be fused with spectral information from the above scanners to enhance biodiversity observation and prediction

• Prism: The Portable Remote Imaging Spectrometer sensor will explore marine and freshwater ecosystem distribution, structure and composition. It is a pushbroom imaging spectrometer with a spectral range from 350-1,050nm and two bands in the short wave infrared.

Holly Bender, from Nasa’s Jet Propulsion Laboratory and the team lead of Prism, explained that they had built the technology by hand for the two planes.

“So on the plane we have two imaging spectrometers, they look at different wavelengths of interest — one is more focused on aquatic and ocean target areas and one a little bit on terrestrial — but they’re both looking out from the bottom of the plane simultaneously. They’re both passive instruments, so we’re not shining any lights or anything like that. We’re looking at reflected sunlight.


From left, Jasper Slingsby, senior lecturer in Plant Ecology and Global Change Biology at UCT; Adam Wilson, BioScape terrestrial science lead from the University of Buffalo; Erin Hestir, BioScape marine science lead from the University of California, Merced; Anabelle Cardoso, BioScape science team manager from the University at Buffalo and University of Cape Town. (Photo: Shelley Christians)

“The sunlight will reflect off of whatever we’re flying over, and then we’re measuring. As we keep moving forward in the plane, we’re measuring more and more at a time,” she explained.

UCT’s Slingsby said their goals are to determine what can be done with this imagery and how useful it will be for mapping and monitoring biodiversity. If all goes according to plan, Slingsby said that the next step would be for Nasa to place the imaging sensors on satellites to provide regular imaging at a global scale.

“The goal is not just to track change, but also to highlight where we might need to intervene to improve conservation.”

South African research partners include the National Research Foundation, the South African Environmental Observation Network, the South African National Biodiversity Institute, South African National Parks and CapeNature.

The science team estimated that funding for the project consisted of about R220-million from the US and R11-million from South Africa. The official launch of the project will take place on 17 November. DM

[Lisbeth]

Study: Tiny tortoise may play large role in South Africa’s Karoo landscape

by Sean Mowbray on 3 January 2024

• The diminutive Karoo dwarf tortoise may play a key role in seed dispersal of plant species in its semidesert habitat in South Africa, a new study finds.

• A germination trial showed the tortoises transport seeds to microsites suitable for germination, a potentially vital means for plants to survive drought in the arid Karoo region.

• The dwarf tortoise is highly endangered due to degradation of its habitat and increased predation by ravens and crows accompanying expanded human presence in the Karoo.

• The findings underline the broader ecological roles that small, understudied species play in landscapes.

The diminutive Karoo dwarf tortoise (Chersobius boulengeri) may play an outsized role as gardener in its arid South African habitat. Researchers gathered droppings of the miniature species — this endangered tortoise is one of the world’s smallest, maxing out at 11 centimeters (4.3 inches) in length — and analyzed them to identify its preferred diet. The newly published research suggests that the tortoises’ dietary preferences may play an important role in seed dispersal of at least four plant species.

C. boulengeri is a cryptic species endemic to South Africa’s Karoo, a vast semidesert area covering around 500,000 square kilometers (193,000 square miles), a region larger than California. Studying the species is challenging because these small tortoises spend most of the day hidden motionless in rock crevices, necessitating long hours peering under rock after rock to spot their tiny camouflaged shells, according to Victor Loehr, first author of the paper, published in the Journal of Arid Environments.

When they do venture out, they spend a lot of that time walking around and scanning their surroundings, behavior that doesn’t make sense for a small species that’s vulnerable to predation, Loehr told Mongabay.

The Karoo dwarf tortoise is highly endangered. In research published last year, Loehr and his team from the NGO Dwarf Tortoise Conservation found that the only known population is crashing due to a combined threat of habitat degradation due to livestock grazing and predation by ravens and crows, which spread across the Karoo landscape following human activity. These two threats have likely led to local extirpations, Loehr said.

As females only lay one egg at a time, and juveniles may take up to a decade to reach maturity, the tortoise populations grow very slowly, which can exacerbate such pressures.

That makes the diet findings particularly important. “If you don’t know anything about what a species is feeding on, then it’s impossible to assess an area for suitability for the species,” Loehr said. Until now, there was limited information on what these dwarf tortoises ate or their role in the surrounding ecosystem.

The research team analyzed tortoise feces using a range of methods and found that while the species ate a host of plants, it had a preference for 10, including doll’s roses (Hermannia spp.), which are relatively scarce in the arid Karoo landscape.


Analysis of dwarf tortoise droppings indicates that they prefer to feast on a few plant species, including doll’s roses (Hermannia grandiflora). Image courtesy of Victor Loehr.


Research efforts relied on volunteers painstakingly searching rock crevices for the 10-centimeter (4-inch) tortoises. “You have to inspect thousands of crevices to find just a handful of tortoises,” Loehr said. Image courtesy of Victor Loehr.

Tiny ecosystem engineers

These preferred meals explained the tortoise’s finicky scanning for food options on its daily forays, but also led the researchers to believe it may have a mutualistic relationship with some of its favored flora. A small germination trial indicated the tortoise does indeed aid some plants’ dispersal and germination.

While the tortoise gets a meal, the plants could benefit as their seeds are transported to microsites suitable for germination, Loehr said. “I do think that in areas with frequent droughts like the Karoo, tortoises may be especially important vectors for seed dispersal during and after drought,” he said.

“I think if we would expand another germination trial based on a larger number of tortoises and maybe more populations, then I would not be surprised if many more [plant] species would be dispersed by this species of tortoise,” Loehr added.

Conservation action to address predation and find other tortoise populations is underway, led by the South Africa-based Endangered Wildlife Trust. Loehr said his organization has collaborated with a range of institutions to breed Karoo dwarf tortoises in captivity with the aim of possibly carrying out wild reintroductions in the future.

“So far, we have discovered that it is possible to successfully keep, breed and raise Karoo dwarf tortoises in captivity,” he said. “That they are capable of dispersing plant species that are not abundant, [which] might make them a useful ‘tool’ in habitat restoration.”

Tomas Diagne, director of the African Chelonian Institute in Senegal, said the study provides a valuable methodology that could be applied to other species such as the much larger but similarly endangered sulcata tortoise (Centrochelys sulcata). “We suspect that this species is playing a key role in the Sahelian ecosystem. Now this paper is going to be something referential to conduct a similar study,” said Diagne, who wasn’t involved in the Karoo study.

“One of the key questions we need to answer is what is the role of these species in the ecosystem,” he added. “If we lose one species of tortoise it is going to impact the ability of the ecosystem to regenerate.”


A Karoo dwarf tortoise fitted with a transmitter for tracking purposes.
The Karoo dwarf tortoise is threatened by ongoing degradation of its habitat and predation by ravens and crows. The spread of these birds comes as a consequence of human activity in the region. Experts say its endangered status and ecological role are emblematic of many other turtles and tortoises, which often receive little conservation and research attention. Image courtesy of Victor Loehr.

For Craig Stanford, a researcher at the University of Southern California and chair of the Tortoise and Freshwater Turtle Specialist Group at the IUCN, the global wildlife conservation authority, the study’s results aren’t surprising as other tortoises play a similar role, but they do underline its importance, despite its tiny size: “It’s not like a giant tortoise, but nevertheless, they have the capacity to be small-scale ecosystem engineers,” he told Mongabay.

“The paper is kind of a small example of the ways in which these animals are underappreciated in their ecological roles,” said Stanford, who wasn’t involved in the study. “They’re not just kind of interesting little moving rocks on the landscape, they actually have ecological roles to play.”