International Citizen Science Day in The Company’s Garden

Photo Credit: Les Underhill

International Citizen Science Day in The Company’s Garden – by Les Underhill

All but one of the thousands of people in The Company’s Garden, in the heart of Cape Town, were there to enjoy the autumn sun, and hoping for rain. I was there to celebrate International Citizen Science Day, Saturday, 14 April 2018. The sun made it easy to take photos for the Virtual Museum (

Photo Credit: Les Underhill

The dragonflies and damselflies, taken together, are called the Odonata. The damselflies mostly fold their wings over their backs, but they are mainly associated with really clean freshwater. So it was a bit of a surprise to find a damselfly sitting on the stalks emerging from the ornamental pond in the top photo.

Photo Credit: Les Underhill

The pair of Egyptian Geese in this pond had one gosling. Probably this was the only one left of a brood; the average starting off size of a brood is eight. This brood shrinkage is not a conservation issue in The Company’s Gardens. There is no shortage of Egyptian Geese.

Photo Credit: Les Underhill

This goose parent used the fountain in the ornamental pond as lookout. Cecil John Rhodes, of Cape to Cairo ambitions, has turned his back on this Egyptian Goose. Reminders of the failure to put a railway from here to Egypt is apparently a stressful topic.

Photo Credit: Les Underhill

The war horses and soldiers of the Delville Wood Memorial have to withstand the unsavoury attentions of the Hartlaub’s Gulls. They provide a great vantage point from which they can swoop down on anyone who scatters any food.

Photo Credit: Les Underhill

The Company’s Garden has a well-maintained section of vegetables. This is the best spot for butterflies. The most abundant butterfly today was the Cabbage White. This is South Africa’s only invasive alien butterfly. It was first recorded in Sea Point, Cape Town, in 1996, and has already expanded its range as far as the Eastern Cape.

Photo Credit: Les Underhill

This African Monarch was still flying in spite of large fractions of its wing area having worn away.

Photo Credit: Les Underhill

Here is a younger and more vibrantly coloured African Monarch.

Photo Credit: Les Underhill

Outside of suburbia, the Garden Acraea, occurs mainly in forest and woodland. It has moved into the suburbs on a large scale, because its favourite host plant on which its caterpillars feed is the Wild Peach Kiggelaria Africana, and these are grown in many gardens.

Photo Credit: Les Underhill

Another species that originally was a forest inhabitant is the Hadeda. This noisy bird has made itself at home in the suburbs, and in The Company’s Garden it happily feeds in the beds while people walk by on the adjacent footpaths.

Photo Credit: Les Underhill

This Grey Squirrel is another introduced alien, which seems to have The Company’s Garden as the epicentre of its Cape Town distribution. Here is one, of hundreds, and it is feeding on an acorn, from an introduced oak tree. So far, there is nothing unusual about all of this.

Photo Credit: Les Underhill

But the squirrel moves off looking like a rabbit. Somehow, it is coping with life minus its bushy tail.

All these photographs will be uploaded to the Virtual Museum. They will be valuable in two ways. They will confirm the continued existence of each species in this locality. And especially for the butterflies, and for the damselfly, these records will provide information on the time of the year when they are in flight. As we move through April, and the weather in Cape Town gets cooler, we anticipate seeing fewer and fewer of these two groups of insects.

BDIgest Saturday, 14 April 2018

Predation risk and plasticity in vigilance behaviour headline our pick of recent research this week. We continue the predation risk theme with an example of climate-mediated changes in predation risk. We look at an overview of the relationship between ecosystem services and population abundance – it is not as clear-cut as one might think. We also have a fascinating paper about co-evolution of a pathogen and its host species. We end off the peer-reviewed section with a thought-provoking piece – an ecological warning to humankind. This week, as a bonus, we have included two articles from popular literature that cover research topics that could be of interest … the scientific paper is dead; the AMOC is running amok. Pieter Cronje is our featured conservation artist this week, with “Tiger Tragedy”. Sign up below if you would prefer to receive this digest as an email.



Cheetah with a hare kill. Photo credit: Pete Laver 2003 (CC BY-NC-SA 2.0)

Cheetahs strategise to deal with cheaters

Cheetahs are sometimes considered the weaklings in their guild, often losing kills (kleptoparasitism) or losing cubs (predation) to larger carnivores like lion and spotted hyaena. A recent study published in Behavioral Ecology and Sociobiology shows how cheetahs in the Serengeti National Park exhibit plasticity in their vigilance and foraging behaviours. Hilborn et al. (2018) draw on a long-term dataset (35 years) and a huge number of observation hours in the field to show how cheetahs balance their predation risk and food intake. Essentially, animals that are at risk of kleptoparasitism but not cub predation (male coalitions and single adult females) reduce vigilance and eat quickly. However, females that have cubs, increase vigilance, delay their own feeding, and spend longer handling the kill – thus allowing these mothers to expend more effort detecting potential predators and allowing their cubs to feed.

DOI: 10.1007/s00265-018-2481-y

Ed: Full disclosure – I know the authors and was privileged to be able to spend some time in the field with them. This is a fascinating ecosystem, and this long-term project has produced some remarkable ecological insights.

Lead author, Anne Hilborn, in the field. Photo credit: Pete Laver 2003 (CC BY-NC-SA 2.0)
Authors, Anne Hilborn and Marcella Kelly. Photo credit: Pete Laver 2003 (CC BY-NC-SA 2.0)
After pushing the field vehicle out for the umpteenth time. Photo credit: Pete Laver 2003 (CC BY-NC-SA 2.0)
Cheetah mother with cubs. Photo credit: Pete Laver 2003 (CC BY-NC-SA 2.0)
Kleptoparasitism. Photo credit: Pete Laver 2003 (CC BY-NC-SA 2.0)
Kleptoparasitism writ large. Photo credit: Pete Laver 2003 (CC BY-NC-SA 2.0)
Food coma. Photo credit: Pete Laver 2003 (CC BY-NC-SA 2.0)
Photo credit: Pete Laver 2003 (CC BY-NC-SA 2.0)





Orange-fin anemonefish (Amphiprion chrysopterus). Public domain: US National Park Service.

Finding Nemo and his cousins just became easier … a tale of cascades, multiple symbioses, climate change, and predation risk

One of the fall-outs of climate change is ocean warming, which is some areas is causing mass bleaching of anemones and corals. Corals and anemones depend upon an algal symbiosis, whereby algal symbionts, zooxanthellae, photosynthesise and provide nutrients to the host organism (which may additionally feed on zooplankton). Many corals kept in the dark (so that their zooxanthellae cannot photosynthesise) but kept with a plentiful supply of zooplankton, will begin to die unless the zooxanthellae return to photosynthesis. Increases in ocean temperature are believed to result in the loss of these zooxanthellae.

In Proceedings of the Royal Society B, recently, and in Nature Communications last year, we find a pair of studies looking at the metabolic and physiological costs of this coral and anemone bleaching on its symbiont, the orange-fin anemonefish (Amphiprion chrysopterus). As with other clownfish and anemonefish, this relationship forms part of a service-service mutualism (anemones provide protection to anemonefish from their predators and vice versa) with a possible service-resource component (waste ammonia from the fish may feed the zooxanthellae).

The two papers show firstly that anemonefish exhibit higher stress hormone (cortisol) levels and lower reproductive hormone (ketotestosterone and estradiol) levels during bleaching events. Further, this is linked to a fitness effect, whereby bleaching events are associated with less spawning, lower egg production, and higher egg mortality.

The authors conclude: “Why anemonefish should exhibit a stress response to host bleaching is not known, but may be in response to a perceived increased risk of predation either from the shrinking of the anemone, or a reduced neurotoxicity of venom from bleached anemones. Alternatively their increased conspicuousness might lead to increased harassment from heterospecifics.”

The more recent paper adds a layer of complexity to this issue, by showing that the anemonefish from bleached anemones had higher standard metabolic rates (SMRs) than anemonefish from unbleached anemones, even though both groups did not differ in their activity levels.

Metabolic costs:
DOI: 10.1098/rspb.2018.0282

Stress hormones:
DOI: doi:10.1038/s41467-017-00565-w

Ed: Similar outcomes have been found for other animals that recently, due to climate change, find their perceived predation risk changing. For example, the snowshoe hare may be shifting its geographic range in relation to the snow-pack (see here). The hares in some areas exhibit a seasonal moult to a white winter coat which provides camouflage against the snow background. Populations that cannot adapt quickly enough to changing snowfall patterns in a warming climate might suffer fitness consequences (getting nabbed by predators due to a colour mis-match, e.g. here) or physiological consequences (as seen in the anemonefish above). Some populations of hares have, however, already developed some plastic moult strategies to prevent this mis-match (again here).





At your service … for now

It is well established that biodiversity is associated with ecosystem services – certain species and community assemblages provide services (sometime unique to that taxon). However, it isn’t immediately clear how declines in population numbers of those species would affect the provision of the services they provide. The simplest a priori assumption might be that the relationships are both positive and linear. Gaston et al. (2018) provide a good overview of this issue in the journal BioScience. They use birds as an example taxonomic group to show that although population abundance and ecosystem service provision are usually positively related, this is not always true, and the forms of the positive relationships may seldom be linear.

DOI: 10.1093/biosci/biy005

Ed: This paper illustrates an important point – we might assume in many cases that the abundance of a species (or population) is linearly and positively related to the services the species (or population) provides, BUT, that relationship may be non-linear and thus include inflection or tipping points.





Variable harlequin frog (Atelopus varius). Photo credit: Brian Gratwicke (CC BY 2.0)

Some froggin’ good news

Amphibians have generally had a rough time as humans have degraded habitat and polluted air and water with toxins and endocrine disruptors. To make matters worse, many amphibian species have suffered dramatic declines in the last two decades, linked to chytrid fungus epidemics. Batrachochytrium dendrobatidis is the fungal pathogen believed to cause chytridiomycosis in amphibian hosts.

Voyles et al. (2018) recently gave us some good news from Panama where they looked at detection of frog species and pathogen and host attributes nearly 10 years apart. The initial data were collected during outbreaks (epidemic or epizootic events) around 2004. Twelve riparian frog species had either been driven to critically-low population levels or had putatively been extirpated by chytridiomycosis. Ten years later, nine of those species appeared to be recovering, even after a period of no detection during the outbreaks.

Typically, it isn’t a good idea for pathogens to wipe out their hosts because they would get wiped out with them. Thus, diseases typically shift from initial epizootic (epidemic or outbreak) phases where hosts suffer high morbidity and mortality to enzootic (endemic) phases where morbidity and especially mortality are greatly reduced. It is not yet well-established how this transition occurs … through attenuation of the pathogen (i.e. its pathogenicity is reduced) or through improved host defenses or decreased host susceptibility. Voyles et al. (2018) show that in this case, Batrachochytrium dendrobatidis is no less pathogenic now than it was ten years prior at the height of the outbreak in Panama. Instead, some of the amphibian hosts appear to have more effective defenses.

DOI: 10.1126/science.aao4806

Ed: This is a really fascinating study and offers some hope for amphibian assemblages that have been ravaged by chytrid fungus. On the issue of co-evolution of a pathogen and its host, this study provides a great entry point, and opens up so many new questions. It would be great to compare this co-evolving system which has a single pathogen and multiple host species, with a system that has a single pathogen with high host specificity (perhaps just a single host species). In the former system, it may well be the case that multiple host species provide reservoirs for the pathogen – i.e. some insurance against obliterating its host. The latter system of a single host species offers less insurance, and I would suspect that pathogenicity might evolve quicker than host defenses to prevent a catastrophic host population crash. 





We need to have a talk …

At the end of 2017 a sizeable portion of the world’s scientific community published a frank warning to humanity (Ripple et al., 2017). This letter had over 15,000 academic signatories from 184 countries. This letter marked the 25th anniversary of the last time such a warning was made – then by more than 1,700 signatories (including most living Nobel laureates in the sciences). Recently, BioScience published some follow-up letters (here, here, and here) and a response from Ripple et al. (2017) (response).

Ripple et al. (2017) summarised broad environmental trends since the previous warning was issued. For the most part those trends have continued unabated, suggesting that, in general, the first warning was not heeded. The only success has been in stabilising the stratospheric ozone layer. They provided 13 potential steps that humanity could take to make the transition to sustainability: 1) prioritising connected, well-funded and well-managed in situ conservation in reserves; 2) halting habitat conversion; 3) restoring habitat on a large scale, particularly forests; 4) re-wilding areas, including re-introducing top predators; 5) enforcing strong policies to prevent poaching, exploitation, and trade of threatened species; 6) reducing humanity’s food waste; 7) promoting dietary shifts to mostly plant-based diets; 8) reducing human fertility rates by increasing access to education and family-planning services; 9) increasing education about, engagement with, and appreciation of nature; 10) redirecting investing and purchasing choices to promote positive environmental change; 11) promoting green technologies and renewable energy production while phasing out reliance on fossil fuel-derived energy; 12) reforming economies to reduce inequality, and to price in environmental externalities; 13) determining and striving for a sustainable long-term human population size.

The follow-up letters briefly address three additional steps to be taken: 14) transitioning economies away from a growth model (the underlying premise is that the finite resources of the planet cannot sustain infinite growth); 15) developing a new global ethic (in which we are part of the biosphere, it is part of us, and morality includes environmental concerns); 16) moving more forcefully as scientists into the realms of policy-making and politics.

And so … the conversation continues …

DOI: 10.1093/biosci/bix125 (2017 letter)
DOI: 10.1093/biosci/biy006 (2018 follow-up – economic growth)
DOI: 10.1093/biosci/biy007 (2018 follow-up – new global ethic)
DOI: 10.1093/biosci/biy008 (2018 follow-up – political power)
DOI: 10.1093/biosci/biy009 (2018 response to all)

Ed: This series of letters is sobering and somewhat depressing. A lot of the recommended steps would appear to be beyond our individual control as they fall into either POLICY or THE MARKET. We should remember though that in most cases, policy and the market are the collective outcomes of a multitude of individual behaviours and decisions (e.g. votes, or purchases). Some of our most effective lobbying may be to lobby the people directly around us – friends, family, colleagues, neighbours – people who at the very least might give us the chance to be heard.




Popular literature



Are scientific papers obsolete?

The Atlantic produced an interesting article about scientific papers and how they may be obsolete in the digital age. The article focuses heavily on the idea of creating computational essays instead – digital files that include data, algorithms, traditional text, and interactive components. Two competing models are introduced – a pay-to-play version from Stephen Wolfram, and an open-source alternative, Jupyter.





Don’t you dare touch that thermostat

Scientific American discusses the Atlantic Meridional Overturning Circulation (AMOC), which plays a vital role in how heat gets distributed around the planet. Previously, in this digest, we have looked at climate oscillations such as El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the North Atlantic Oscillation (NAO) (see here). AMOC could have even bigger impacts on humankind, and it appears that there is now evidence that AMOC is undergoing some change – specifically a slowing down of the currents. The links between climate change, melting Arctic ice, resulting changes in water density in the North Atlantic, and ultimately changes to AMOC, all make for grim but important reading.






Conservation Art this week


A new prison uniform … striped, and orange?

The featured conservation artist this week is Pieter Cronje. He is a human rights lawyer with a master’s degree in Human Rights Law, with Environmental Law as one of his subjects. He was born In Oudtshoorn, South Africa. He started drawing and painting when he was in high school. He also studied history of art and spent many hours at the arts faculty of the University of the North West in Potchefstroom while he was doing his military service. As a human rights lawyer he has traveled to many countries which have both serious human rights issues and environmental issues. Environmental issues were always part of his inspiration and are depicted in many of his paintings. Pieter’s contribution to the Virtual Museum has been massive; he has submitted 27,000 records from 22 countries.

“Tiger tragedy” 2017 by Pieter Cronje. Oil on stretched canvas, 46 cm x 46 cm
“Tiger tragedy” 2017. Oil on stretched canvas, 46 cm x 46 cm.
Pieter says: “During 2017, I had the opportunity to train police in Punjab, India, on how to respond to violence against women. The police invited me to visit a nature reserve (Tiger Reserve) in what they refer to as Kipling country. This is the area of India which inspired the English author Rudyard Kipling to write the Jungle Book. They originally took me to a zoo to see tigers which really saddened and frustrated me. After some discussion they agreed to take me to see the real thing. After one night on the train I was fortunate to see three tigers in the wild. Unfortunately, most of the tigers nowadays are in cages. This picture shows the fear and majesty of the tiger kept in a broken cage. Sadly, this is a highly threatened species in high demand from Chinese traditional healers for tiger bones. They also use the skins for a dancing ceremony in Tibet, although the Dalai Lama requested the local Tibetan people not to use tiger skins. The tradition was taken over by the Chinese staying in Tibet as a sign of power and wealth. Also represented is the Emperor of India Butterfly, also known as Kaiser-I-Hind, Teinopalpus imperialis, is also a highly endangered species due to habitat destruction and butterfly collectors.”
Pieter says: “As a human rights lawyer, I also always challenge people about the destruction of the earth and the decline of species and what they can do about it. I work with law enforcement agencies all over the world and focus on human rights related issues such as human trafficking and domestic violence; but I also talk about the environment to my learners and this is always an important part of every workshop to law enforcement officials. For the past few years my paintings have become a social commentary after my visits to some of these places.”
Have a look at a selection of Pieter’s paintings by visiting





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Editor, BDIgest





Biodiversity and Development Institute

Paardeberg site report – 2018/04/07

By Les Underhill. Photo credits: Les Underhill & Dieter Oschadleus

Team BDI explored the northwest corner of the Paardeberg on Saturday 7 April 2018. We visited the part of this mountain range which is closest to Malmesbury. Technically, the Paardeberg is a series of granite plutons – dome-shaped hills. It was called the Paardeberg because, when discovered, it had been inhabited by quaggas, which to the early settlers were horselike. This is a fascinating area, and one we plan to revisit.

We joined an expedition led by Arnold van der Westhuizen to check two camera traps. Leopard scats had been reported here recently, and the cameras had been set up in the hope of confirming the presence of this seldom-seen animal. We found leopard scats and uploaded them to MammalMAP:

On the foothills of the Paardeberg, the main crop is grapes, but there was no water in the farm dams for irrigation this summer, and there was no harvest in the higher lying vineyards. Above the agricultural areas is a band of renosterveld. Go a little higher, and the proportion of plants which are proteas, ericas and restios increases, and renosterveld gives way to fynbos.

The camera traps had taken a total of 44 photos. All of them turned out to be baboons, and some were caught in some unusual poses! Maybe a leopard or two would help create a “landscape of fear” for the baboons.

Cape Black-Eye
Cape Black-Eye

At the end of long, dry, drought summer, biodiversity was scarce. This was one of only two butterflies we saw. It is a Cape Black-eye Leptomyrina lara ( This is a species that frequently rests on bare ground, and did so for us. The Cape Black-eye occurs mainly in the more arid western half of South Africa, in Lesotho and it also occurs northwards into Namibia. This is the sixth record of the species in the Paardeberg, and the others have also been within a few kilometres of this spot.

Crimson-speckled Footman

The Crimson Speckled Footman Utetheisa pulchella is a moth that flies in the daytime ( It looks like a white butterfly in flight; but when it is settled the red and black pattern on the white wings makes it instantly recognisable. These moths are unpalatable to birds; the bold wing colours serve as warning to predators: “I am toxic”, or, in technical terms, “I have a condition called aposematism.” The Crimson Speckled Footman has a wide distribution across Africa and southern Asia. The South African distribution map should show an almost continuous range.

We didn’t see any mammals, not even a baboon, but we did find this porcupine quill and submitted it to the MammalMAP section of the Virtual Museum (

Two species scorpions were found. This one is Uroplectes carinatus ( The scorpions don’t yet have English “common” names, like the birds, butterflies and dragonflies do. The identity of the second species is still being debated by the specialists (

We are grateful to Arnold van der Westhuizen for being our guide.

BDIgest Friday, 6 April 2018

This week, we take a look at a fascinating study on a migratory bird and how the authors teased out potential drivers of population trends. We also see an interesting experimental study about our tendency to redistribute wealth and our capacity for tolerating inequality. Finally, we look at three methods papers – one that tackles pseudoreplication, and two that address remote sensing.



Vermivora chrysoptera: Mark Peck 2013 (CC BY-NC-SA 2.0)

Birds of a feather don’t necessarily flock together

In a remarkable study reported (with commentary) in PNAS, we learned this week about “migratory connectivity” – a strong association between geographically-distinct breeding and nonbreeding areas. Kramer et al. (2018) determine the cause of population declines in one distinct breeding population of golden-winged warblers, by bringing together several lines of evidence. They used migratory data (70 individuals with geolocators), long-term (since 1966) citizen science population trend data, and land cover data for nonbreeding sites for two congeners, blue-winged and golden-winged warblers. These species are ecologically similar and migrate between approximately similar regions. This setup provided a good phylogenetic control. The breeding population of golden-winged warblers from the Appalachian Region appears to be in decline, while the other breeding populations of this species and breeding populations of the blue-winged warbler appear relatively stable. The blue-winged warblers exhibit weak migratory connectivity, with somewhat distinct breeding populations mixing in their nonbreeding area. The golden-winged warblers, by contrast, exhibit strong migratory connectivity with distinct breeding populations using distinct nonbreeding areas. The only declining population, from the Appalachian breeding site, was also the only population of either species to over-winter in northern South America, where it appears that habitat degradation (forest loss) may be linked to the population decline.

DOI: 10.1073/pnas.1718985115
With commentary:
DOI: 10.1073/pnas.1802174115

Ed: This study is quite unique in its breadth, depth, and use of phylogenetic controls. Deploying enough geolocators and recapturing 70 of the tagged birds after a year is phenomenal and provided a rich dataset on migratory movements in these two species. Having Breeding Bird Survey data going back to 1966 also provided a clear picture of population trends for both species, which, in turn, represented a neat phylogenetic control.




A little bit of Robin Hood doesn’t go enough of the way

Why do we struggle with inequality? Bechtel et al. (2018) try to answer that question using an experimental game played by a large number of German and United States study subjects (nearly 5000, in total). All participants were placed in random “pairings” whereby both participants recieved a “payout”. The pair partners were unknown to each other. The distribution of the winnings were such that the participant won either USD 25 (versus USD 75, i.e. disadvantageous inequality within the pair), USD 50 (versus USD 50, i.e. equality within the pair), or USD 75 (versus USD 25, i.e. advantageous inequality). Each participant was allowed to give to or take from their partner any sum they pleased. In general, participants tried to redistribute the winnings more equitably when they were in either inequality pairing: participants who received USD 25 took money from their USD 75 partners, and USD 75 participants gave money to their USD 25 partners. Even though the difference in winnings in the inequality pairings was USD 50, participants only gave/took USD 10 to/from their partners (on average). This would suggest that people try to apply some redistribution of wealth, but are generally quite comfortable with retaining relatively large inequalities – even when the starting point for both partners in a pair was essentially a luck-based lottery winning.

DOI: 10.1073/pnas.1720457115

Ed: Even though the dollar values in this study were somewhat trivial, this study still gives important insight into human behaviour with regard to tolerance of inequality and redistribution of wealth. Some of the study strengths include a very large sample of participants (who were representative of the adult voting public), and a “survey instrument” that allowed participants to both donate to and take from their partners.




Tetrao urogallus: David Palmer 2012 (CC BY 2.0)

Crying fowl over pseudoreplication

Individual variation in physiological responses to stressors, and individual variation in metabolism of circulating stress hormones are both relatively under-appreciated aspects of non-invasive hormone monitoring. Coppes et al. (2018) address this issue in an extensive study of faecal glucocorticoid metabolites in the capercaillie in Germany. The authors modeled (as the “full” model) the variability in the faecal glucocorticoids using several environmental parameters and animal sex (as fixed effects), and controlled for the individual variability using a random effect for animal ID. The authors then compared this model to a “naive” model that assumed each sample was independent and thus allowed for pseudoreplication (treating non-independent samples from the same animal as independent samples). The full and naive models differed in which parameters were considered significant and differed in how much variance was explained.

DOI: 10.1111/1365-2664.13140

Ed: Although treating repeated measures from individuals is an important step in analysis, as the authors highlight, the broader issue that this study exposes, is the problem of pseudoreplication. By removing the random effect for individual ID in the “naive” model, the authors were actually incorrectly increasing the effective sample size by assuming that the multiple samples from a given individual all contained unique information. Naturally, this would change how much variance could be explained by the model, and it could allow additional variables to be selected as significant, simply by inflating the sample size. The important take-home message here might be that researchers need to think clearly about pseudoreplication during study design (incorporating sufficient spatial or temporal separation in sampling to reduce pseudoreplication) and during statistical analysis (for example by using a random effect in a random effects or hierarchical model).




Sixth sense

Remote sensing offers the promise of being able to monitor biological populations in areas that are difficult or dangerous to reach, with ease, speed, and costs that might outperform traditional human observers. However, to date, remote sensing has mostly been used successfully when counting large animals across a relatively small spatial scale when the background substrate is relatively homogeneous. As this review in Methods in Ecology and Evolution shows, there are still a number of obstacles to overcome before remote sensing can play a larger role in monitoring biological populations. Some of these obstacles include the cost of high-resolution data, and the ability to automate the organism detection and counting process, which is currently still subject to error.

DOI: 10.1111/2041-210X.12973

Ed: This is a field ripe for further development and improvement, both in counting animal populations and plant populations (not addressed in the review).




Drones for clones

As an example of one of the scenarios where remote sensing may prove helpful in counting animal populations, Hodgson et al. (2018) performed rigorous ground-truthing for drone-based remote-sensing of a seabird colony. The authors created replicas of seabirds of known number so that they could compare the accuracy of ground-based counts by human observers with counts based on drone imagery processed manually or with a semi-automated process. The drone-based counts were more accurate than the ground-based counts.

DOI: 10.1111/2041-210X.12974

Ed: This study demonstrates an important aspect to any remote sensing study – the need for rigorous ground-truthing. The drone method appeared to work well in this contrived example, but, it should be noted that the background substrate – beach sand – was homogeneous and the replica birds on nests represented large detection targets. If a drone-based count is going to work for any animal population – this would probably be it.






Every dog has its … picture painted

This week’s conservation art profile:

Depicting 4454 wild dogs all individually hand painted. Caitlin O’Gorman’s representation of what is left in the wild. Oil on canvas. 2m x 1.8m

Caitlin grew up mostly in Ireland, and completed her final years of schooling in KwaZulu-Natal. She has sketched and painted for as long as she can remember. Our lives are full of accidental stories which take us in unexpected directions. One of the happiest accidents in Caitlin’s life was discovering the Michaelis School of Fine Art at the University of Cape Town. In 2018, she is in her fourth and final year as an undergraduate, and a key component of the year is a display of what drives and inspires the people in her class. For Caitlin it is conservation and therefore, she plans to work in collaboration with the Landmark Foundation to discover the inspiration for her project. Watch this space.

From Caitlin:

I am a fine art student currently in my fourth and final year of studying. I have always had a strong passion for wildlife and my art has resulted in always taking the shape of that subjectivity. In my practice in recent years, I attempt to convey to the viewers the emotions that I feel about wildlife and it’s current state. Although there is a lot of good happening with wildlife conservation, there is dramatic negative activity happening and I attempt to portray this human-wildlife co-existence in a way that challenges the viewer and engages them with a more emotive and connected response. As a visual representation of statistical information, I hope to allow the viewer to truly see the stats rather than read, and in turn to draw the viewer in to empathize with the subject.




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Pete Laver
Editor, BDIgest



Biodiversity and Development Institute

Lacewings at Little England, Beaufort West

Nesoleon boschimanus. Photo credit: Les Underhill (2018)

Report by Les Underhill

Lacewings are not one of the charismatic groups of insects, and have been poorly studied. They consume aphids and do pollination, so they are one of the key ecosystem service providers, and deserve better attention than what they have received to date. There is only one entomologist in South Africa who has focused on lacewings, Dr Mervyn Mansell, at the University of Pretoria. He says that, in South Africa, there are currently 415 described species in 14 families of lacewings. There are many taxa that await description, and he reckons that we should eventually end up with about 500–550 species for South Africa. For the whole of Africa, it is likely that there will prove to be 1000–1500 species.

On three trips to the Landmark Foundation’s farm at Little England in the Karoo north of Beaufort West a total of 18 lacewing have been photographed and uploaded to the LacewingMAP section of the Virtual Museum ( 13 have been identified to species level, three to genus and, for one, the photo was only good enough for the ID to be done to family. The number of species so far is a paltry six! But it is a start. These are the first ever records for this grid cell.

Mervyn Mansell, who does the identifications for LacewingMAP, reckons that we could expect at least 50 species in that area. “It is actually an extremely rich area for lacewings. Lots of fieldwork needs to be done here.”

The first six species for this grid cell are listed below. The species notes were written by Mervyn Mansell in his comments on the identification. The number of records to date is given, as well as the link to the record in LacewingMAP with what is currently the best available photo of the species in the grid cell. The distribution map for each species, based on the LacewingMAP database, is also provided. The take home message from these maps is plain: Our knowledge of the distributions of the lacewings is weak.

Systematic list of lacewings recorded on the farm Little England

Centroclisis maligna. Photo credit: Les Underhill (2018)

Centroclisis maligna (Myrmeleontidae)

This species is fairly common and widespread in the drier western parts of southern Africa. It is readily distinguished form other Centroclisis species by its reddish colour. The large robust three-toothed larvae live freely in sand and do not construct pitfall traps.

One record:


Creoleon mortifer. Photo credit: Les Underhill (2018)

Creoleon mortifer (Myrmeleontidae)

A common and widespread species, occurring throughout most of southern Africa and northward. It is highly variable, often with black streaks in the wings that have led to numerous synonyms. Rests with wings wrapped around the body. Larvae live freely in sand.

Two records:


Myrmeleon doralice. Photo credit: Les Underhill (2018)

Myrmeleon doralice (Myrmeleontidae)

This species is common and widespread throughout southern Africa, particularly in the drier areas. Larvae construct pits and are pinkish in colour. Although the adults are fairly common, the larvae are not frequently encountered, although they are pit builders, and usually occur in open exposed situations.

Three records: m


Nannoleon michaelseni. Photo credit: Les Underhill (2018)

Nannoleon michaelseni (Myrmeleontidae)

This species is widespread in South Africa and Namibia, and is fairly common in the drier western parts of the subregion. It is currently the only species in the genus, although another undescribed species is also known. It is characterized by the broad clear wings and long clavate antennae. Nothing is known of its biology.

Two records:


Nesoleon boschimanus. Photo credit: Les Underhill (2018)

Nesoleon boschimanus (Myrmeleontidae)

This species is widespread in South Africa and Namibia, and is fairly common in the drier western parts of the subregion. It is currently the only species in the genus, although another undescribed species is also known. It is characterized by the broad clear wings and long clavate antennae. Nothing is known of its biology.

Three records:


Dichochrysa tacta. Photo credit: Les Underhill (2018)

Dichochrysa tacta (Chrysopidae)

Another of the “brown” “green lacewings”. Fairly widespread and common in the drier western parts of South Africa. Not known from neighbouring countries. Larvae live freely on vegetation, where they are active predators.

Two records:


We are grateful to the Landmark Foundation for their warm hospitality at Little England. Mervyn Mansell’s role in doing the identifications and writing the comments is crucial to the success of this project.

The data were extracted from the LacewingMAP section of the Virtual Museum (Animal Demography Unit (2018). LacewingMAP Virtual Museum. Accessed at on 2018-04-02)


Bird ringing report – Paardeberg 2018/03/28

Cape robin-chat (Cossypha caffra). Photo credit: Dieter Oschadleus (2018)

Cape robin-chat – Virtual Museum record

Report by Dieter Oschadleus

The Paardeberg stands out as a mountainous island in an agricultural landscape between Paarl/Wellington and Malmesbury in the Swartland region of the Western Cape. Very little bird ringing has taken place here, so Les Underhill and I had a ringing session on Bowwood Farm on Wednesday.

The top species was Cape White-eye (n=22), followed by Southern Masked Weavers (n=8), where 2 of the latter were males in partial breeding plumage. The ring of one bird has been recovered in the Paardeberg area, a Cape Weaver ringed with ring 231054 in Tygerberg.

Thanks to Julian and Bridget Johnsen for hosting us!

Streaky-headed seedeater (Serinus gularis). Photo credit: Dieter Oschadleus (2018)

Streaky-headed seedeater – Virtual Museum record

Karoo prinia (Prinia maculosa). Photo credit: Dieter Oschadleus (2018)

Karoo prinia – Virtual Museum record

Cape weaver (Ploceus capensis). Photo credit: Dieter Oschadleus (2018)

Cape weaver – Virtual Museum record

Southern masked-weaver (Ploceus velatus). Photo credit: Dieter Oschadleus (2018)

Southern masked-weaver – Virtual Museum record

Olive thrush (Turdus olivaceus). Photo credit: Dieter Oschadleus (2018)

Olive thrush – Virtual Museum record

Cape white-eye (Zosterops virens). Photo credit: Dieter Oschadleus (2018)

Cape white-eye – Virtual Museum record

BDIgest Friday, 30 March 2018

In this week’s digest of research that caught our attention, we look at socio-economic and development issues associated with background climate oscillations and anthropogenic-driven climate change. We also look at climate change mitigation and biodiversity conservation, artificial selection pressures on a large carnivore, and methods of estimating population density in an elusive carnivore species.



Bet the farm – rolling the climate dice

Food security around the world is closely linked to climate variability, but in a recent article in Nature Communications we learn just how extensive the problem is. Crop productivity on two-thirds of the world’s cropland is significantly affected by three climate oscillations: El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and the North Atlantic Oscillation (NAO). The areas affected by the three oscillations are inhabited by approximately 4 billion people and contribute two-thirds of global food crop calorie production.

DOI: 10.1038/s41467-017-02071-5

Ed: Against this background, the implications of adding variability and unpredictability of anthropogenic-driven climate change would suggest that risk in crop farming and food security will only increase for half the world’s population.




Photo credit: CDC Global 2012 (CC BY 2.0)

The carbon sins of the rich shall be visited upon the poor

The world’s population is becoming increasingly urban, and recent rapid urbanisation has resulted in a proliferation of informal urban settlements or slums, which are home to > 800 million people. Some of this urban migration may be due to food security risk associated with climate variability (such as described in the article above). A compelling article in Ecological Indicators provides an important example of the social science required for assessing climate change vulnerability in these at-risk urban communities. In the particular slum community studied, overall vulnerability to climate change was high, there was a high information barrier (and hence low awareness of climate change impacts). As might be expected, for coping strategies, financial and food support were deemed important, followed by information support.

DOI: 10.1016/j.ecolind.2018.03.031

Ed: Interestingly, technological support was deemed least important for coping with climate change in slum communities, yet much attention is focused on technological interventions and relatively little attention is given to practical information and resource distribution.




Photo credit: Bobulix 2010 (CC BY-NC-ND 2.0)

Picking winners and losers – conserving carbon or biodiversity

Although the net impact of climate change is likely to be negative for biodiversity, there will be some taxonomic groups that benefit from climate change. Carbon conservation – specifically, conserving above-ground carbon stocks in tropical forests – is seen as one of the ways to combat climate change. Contrary to the putative net effects of climate change, it is tacitly assumed that this form of carbon conservation will promote biodiversity. A thought-provoking article in Science Advances suggests that the relationship between above-ground carbon stocks and biodiversity differs for different taxonomic groups, and may also differ in re-growth forests compared to old growth forests (within a taxonomic group). Thus, among the taxonomic groups studied, the relationship between carbon stocks and biodiversity could vary from positive to negative and could appear linear or non-linear. Choosing a single climate change mitigation strategy, such as conserving tropical forests to maximise carbon stocks, will inherently include trade-offs in biodiversity in certain taxonomic groups. A similar article in Science Advances from 2017 about using fire suppression in savannas to maximise carbon sequestration came to similar conclusions. Thus, more nuanced, integrated approaches that consider both carbon conservation and biodiversity conservation (across multiple taxonomic groups) may be required as we try to mitigate anthropogenic-driven climate change.

DOI: 10.1126/sciadv.aar6603

Ed: This is going to be a tricky concept to grapple with. Climate change in general is leading to population declines, geographic range shifts (and expansions or contractions). When biodiversity is already a climate change concern, how will we weigh the biodiversity benefits of mitigating climate change against the potential biodiversity costs (in some taxa) of maximising carbon conservation? As a species, we will need to become much better at assessing risks, attributing value, and optimising trade-offs.




Photo credit: Karlafg 2010 (CC-BY-SA-3.0)

Survival of the … slowest?

Typically, in harvested populations, the selection pressure of hunting or harvest should select for accelerated life history traits. However, research on a hunted population of brown bears in Sweden, published this week in Nature Communications, shows that when hunting regulations prevent the harvest of mothers with cubs, selection pressure may favour slower life history traits. Mothers that exhibit longer maternal care receive a survival benefit. Interestingly, this survival benefit cancels out the loss of reproductive opportunities associated with the slower breeding strategy, such that net fitness for the slower breeding females is similar to that of females following a “normal” maternal care strategy. Over the last 30 years, the proportion of litters in the population raised over 2.5 years has increased measurably relative to the proportion of litters raised over 1.5 years.

DOI: 10.1038/s41467-018-03506-3

Ed: A great demonstration of artificial selection at work … and over a relatively short time-frame for a long-lived large mammal.




Photo credit: Lukas Kaffer 2007 (CC-BY-SA-3.0)
Leopards are contagious too,
Be careful tiny tots,
They don’t give you a temperature
But lots and lots of spots
(Spike Milligan)

Spotty spotting of the spotted

A major issue in biodiversity research revolves around how to count animals in a population or estimate their population density reliably. This is particularly problematic for “cryptic” species that have low detection probabilities. Solitary felids often fit into this category, including leopards (Panthera pardus), which are largely nocturnal and have coat patterns that provide good camouflage. In a great study reported in the African Journal of Ecology, leopard density was estimated across a broad geographic region in South Africa (the Eastern Cape Province and Western Cape Province). The authors used movement data of collared animals and “captures” from remotely-triggered cameras to estimate density using two different techniques – which provided surprisingly similar final density estimates. These density estimates of approximately 1 leopard per 100 sq km are low compared to published estimates for populations elsewhere in the leopard’s geographic range (published, for example, here). Even within this region, density estimates varied greatly among sites (from 0.24 to 1.89 leopards per 100 sq km).

DOI: 10.1111/aje.12512

Ed: This study produced great congruence between two different methods of estimating leopard density, suggesting that the reported densities for the region are quite reliable. The study also opens up interesting questions about what drives variability in leopard population density (both within this geographic region, and across the leopard’s geographic range).






I can’t believe it’s not butter!

This week’s conservation art profile:

Malachite Kingfisher (oil painting … not a photo!) by Tanya Scott.

Tanya has recently completed an MSc at the University of Cape Town using the data from the bird atlas project in South Africa (Birds along a transect across KwaZulu-Natal: altitudinal preference and altitudinal migration). She represented South Africa in the half-marathon at the 29th Summer Universiade in Taipei City in 2017. Her last formal art education was at Westerford High School in Cape Town where the art teacher was Mr Anthony Cain.


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