Having reached mammals in our meanderings, and the human involvement in global plant dispersal (admirably explored in Michael Pollanβs book The Botany of Desire) notwithstanding, we couldnβt ignore our nearest and dearest living relative, the critically-endangered chimpanzee (Pan troglodytes verus), in this curious catalogue of βchory. Kimberley Hockings et al. report on the dispersal of human-cultivated cocoa (Theobroma cacao) by wild chimpanzees in a forest-farm matrix habitat in the village of Bossou (southeastern Republic of Guinea, West Africa) (International Journal of Primatology 38: 172β193, 2017; doi: 10.1007/s10764-016-9924-y).
Although humans are quite adept at tending and dispersing this plant, the chimpanzee contribution β averaging 407 m (range: 4β1130 m) from the cocoa plantation β is arguably a bonus from the plantβs perspective. However, unless the seedlings that developed from translocated seeds were in an established cocoa plantation β where human farmers would tend to them β they did not set fruit. So, a human association is still needed. But, and almost straying into territory that considers the rights of non-human animals, Hockings et al. conclude that their βlocal-scale findings emphasize the complex behavioral and ecological interconnections between coexisting humans and primates in agricultural landscapes and generate interesting questions regarding primate niche construction and crop βownershipβ related to who βplantsβ the crop.β
Emphasising the important role of primates in plant dispersal more generally, Barbara Haurez has examined the part played by western lowland gorillas (Gorilla gorilla gorilla) in Gabon (Africa). Her conclusion is that these primates are important to the regeneration and dynamics of Congo Basin forests. Unfortunately, in the wild, the western lowland gorilla is critically endangered, due to such threats as their capture, killing, and cooking by humans who consider eating such βbush meatβ, a highly-prized βdelicacyβ. But not only is such thoughtless slaughter bad for the gorillas, it is not good for the ecology of the areas where these magnificent mammals live and where they help to maintain plant numbers and diversity. One would like to think that work of scientists such as Huarez will encourage βthe implementation of gorilla conservation strategies as critical to ensuring the preservation of tropical forest ecosystemsβ.
And itβs not just the mobile, living gorillas that have value for plant dispersal and forest regeneration. Augustin Basabose considers the value of seed-loaded dung of apes. To date, planting native tree seedlings is the most common strategy for restoring tropical forests. An additional strategy, proposed by Basabose, is to use intact seeds found in gorilla and chimpanzee faeces as a cost effective and non-invasive way to restore native forested habitats in the Kahuzi-Biega National Park, a UNESCO World Heritage Site. Preliminary results are encouraging with very high % germination of such dung-extracted plant species as Allophyllus kivuensis and Syzygium parvifolium.
However, rather than the time-consuming, labour-intensive practice of searching for seeds within, and extracting them from, the ape faeces, mightnβt a better way be to spread the balls of dung over the area to be replanted letting nature take its course and allowing the seeds to germinate naturally amongst the nutrient-rich faecal material? In that way, a more natural planting could be achieved with the seedlings emerging from the dung competing with each other so that only the fittest individuals survived. Plus, by leaving the seeds within the excrement they will have the added boost of extra β and free β nutrients to get them started on their journey of growth and establishment. One can even imagine balls of dung being liberally strewn over the area to be revegetated in a quite literal scat–tergun wayβ¦
[This is part 3 of a multi-part series of short items celebrating the creatively imaginative and enterprising ways in which plants dupe poor unsuspecting animals into doing their sexual biddingβ¦]Image credits: Chimpanzee by Thomas Lersch; Gorilla from Adrian Pingstone
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