Plants eaten by the African bush elephant in the Cape Floristic Region, part 1

One of the remarkable biogeographical features of southern Africa is the incidence, until recently, of up to four species of megaherbivores (elephants, rhinos and hippos) under temperate climates - in vegetation quite different from that usually associated with Africa.

What is particularly surprising is that the largest-bodied of all, the African bush elephant (Loxodonta africana), has survived to this day near the southern tip of the continent (https://en.wikipedia.org/wiki/Knysna_elephants), at a latitude in line with Buenos Aires, Los Angeles, Sydney and Casablanca.

The diet of the African bush elephant near its southernmost limit is of interest because the location of the last survivors:

Because the remaining population has dwindled to just one individual, no further data are likely to be collected on the diet of Loxodonta africana at this edge of its habitat.

So now seems a good time to review the various mainly anecdotal/inferential strands of information (e.g. https://journals.co.za/doi/pdf/10.10520/AJA00423203_2578 and Milewski, A. V. (2002) Elephant diet at the edge of the Fynbos Biome, South Africa. Pachyderm 32: 29-38).

The following refers to my own study based on the observations of forest guards Wilfred Oraai and Karel Maswati.

FOLIAGE (and bark*)

Trees of afromontane forest (https://en.wikipedia.org/wiki/Afromontane):

Shrubs of thicket and/or the edges/understorey of afromontane forest:

Herbaceous plants (including lianes and tree-ferns) in afromontane forest/thicket:

Shrubs of fynbos (https://en.wikipedia.org/wiki/Fynbos):

Herbaceous plants of fynbos:

to be continued...

Posted by milewski milewski, January 14, 2022 01:40

Comments

Most interesting read, may I ask what is your perspective on the topic of elephant population carrying capacity in south africa (ie. what could the theoretical optimal be for the cape floristic region..)?

Posted by gingko_biloboa1 3 days ago (Flag)

@gingko_biloboa1 Hi Michael, Many thanks for your comment and question. I cannot quantify carrying capacity, but I may be able to point out some relevant principles. There is little doubt that L. africana moved extensively from season to season and in response to wildfires, making the carrying capacity of any given vegetation type or small compartment of land rather meaningless. The dwindling and imminent extinction of the population in the Knysna area may be because this population has long been unable to follow the former migratory/nomadic routes. The overall density of the population of L. africana in the Cape Floristic Region, with its vegetation of fynbos, renosterveld, and afromontane forest, was probably as great as that of the miombo ecosystem that covers much of southern-central Africa, and it probably exceeded that of the miombo ecosystem in Angola, a country in which megaherbivores seem to have been remarkably scarce even before European arrival. So there is no reason to believe that L. africana prefers tropical over temperate climates. Loxodonta africana seems to be most abundant on substrates with moderate nutrient-richness, becoming scarcer on both nutrient-rich substrates and nutrient-poor substrates. Fynbos and miombo woodland are both nutrient-poor vegetation types, but the Cape Floristic Region and the miombo ecosystem include patches of nutrient-richer soils. So what I am suggesting is that the population of L. africana in the southwestern Cape of South Africa was overall about on a par with much of Africa. When we think of the natural community of herbivores in the Cape Floristic Region as a whole, we should think of L. africana as not only part of this community but an important part - despite the likelihood that L. africana was transient in any given patch. Confining the 'Knysna elephants' to afromontane forest/fynbos has not worked in the longer term, and no other conservation area in the Cape Floristic Region is extensive and varied enough in its substrates to allow the reintroduction of the species as a fully wild animal. For me one of the most remarkable aspects of the 'Knysna elephants' is that the most massive land mammal on Earth, by virtue of its intelligence and ability to hide from humans, has managed to survive as a wild animal in an area from which Taurotragus oryx (https://en.wikipedia.org/wiki/Common_eland) and all the other mammals larger than Potamochoerus larvatus (https://en.wikipedia.org/wiki/Bushpig) were exterminated many decades ago. This persistence has been despite the fact that the afromontane forest/fynbos habitat of the Knysna area (https://en.wikipedia.org/wiki/Knysna) is unable to support a breeding population of L. africana and because of the exceptional attunement of L. africana to human ways over its entire evolutionary history as a species. Does this answer help?

Posted by milewski 3 days ago (Flag)

Thank for the reply. Very detailed explanation

Posted by gingko_biloboa1 3 days ago (Flag)

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