Ask porcupine researcher Christy Bragg the obvious question – How does she collar a large, territorial rodent armed with sharp quills? – and she’ll tell you: “Carefully . . . after it’s sedated.”
But of course.
More to the point, then: Why does Bragg traipse around after dark, toting traps and custom-made GPS collars, scouting southern Africa for burrows occupied by Hystrix africaeaustralis, a species that, far from being threatened, is downright common?
Charismatic though porcupines are, she brags, these herbivores also work as “ecosystem engineers” in the Succulent Karoo and therefore rank as VIPs in this arid biodiversity hotspot.
Through widespread foraging pits, soil turnover and numerous burrows, porcupines help maintain endangered plant populations as well as plant diversity in the Koue Bokkeveld, says the University of Cape Town researcher.
The Critical Ecosystem Partnership Fund, with Boekenhoutskloof Wine Estate, sponsors Bragg’s work in Nieuwoudtville, a study site filled with diverse and threatened vegetation.
“It’s a treasure-trove of geophytes,” she says, referring to plants with underground storage organs. “(Here is) the greatest species richness of geophytes anywhere in the world.
“And of course a porcupine’s favorite food is a geophyte, so there are lots of porcupines here. It is the interaction between plant and porcupine that fascinates me.”
The porcupines’ digging for geophytes encourages soil turnover, provides fertile sites for plant recruitment and ultimately enhances productivity and diversity.
“This happens,” Bragg explains, “because soil, nutrients and organic matter and water collects in these little holes and makes them rich fertile oases in the landscape.”
Straddling the boundary between the Cape Floristic Region and the Succulent Karoo biodiversity hotspots, the Bokkeveld Plateau has great plant diversity (1,350 species) and many species found nowhere else. Renosterveld vegetation is threatened: Less than 2 percent remains in South Africa and just 30 percent of Renosterveld that was in Nieuwoudtville is left.
Bragg’s research goal is to compare porcupines’ foraging patterns across different ecosystems.
Eventually, she aims to have 16 collars on porcupines – five each in the Succulent Karoo, the Nama Karoo and the Kalahari Desert, and one on a Franschhoek farm owned by Boekenhoutskloof Wine Estate in the Cape Floristic Region Hotspot.
The two recently collared porcupines were guinea pigs, so to speak. After their trapping and sedation came the really prickly step: affixing custom-made collars between the crest quills of their heads and their long back quills.
“The porcs have very small quills or spines covering the whole of their bodies and we let the collar rest on these,” Bragg explains. “We then became a bit innovative and made sure the collar wouldn’t slide up and down the neck by fastening the crest quills over the collar together with a cable tie. This does not hurt the porcupine at all and prevents the collar from chafing against the neck.”
Come sunset the day after the capture/collaring, Bragg sat glued to her laptop, monitoring the individuals’ real-time movements.
“And lo and behold, the female from the Dolerite Koppies came out of her burrow, made off into the Koppies for some geophyte nibbling, went to visit a neighboring burrow (probably showing off her new necklace) and then spent a while in front of her burrow, no doubt eating the snacks I left for her in case she didn’t feel up to foraging that night,” Bragg reports. “I am tracking both porcs now and getting some amazing data already.”