How does the Namib desert support three species of megaherbivores?
(writing in progress)
Fog from the cold Atlantic, containing iodine
Water and silt run into, not through, the desert
Freshwater springs (even Oryx needs to drink in this environment)
Diggings by termites
Plants mutualistic with large herbivores, e.g. Vachellia (carob-type pods) and melons
Succulent plants, including Euphorbia (https://www.researchgate.net/profile/W-Dean/publication/292791473_An_association_between_a_stem_succulent_Euphorbia_damarana_and_a_leaf_succulent_Aloe_asperifolia_in_the_Namib_Desert/links/5d80f2ca92851c22d5dec589/An-association-between-a-stem-succulent-Euphorbia-damarana-and-a-leaf-succulent-Aloe-asperifolia-in-the-Namib-Desert.pdf) and ?geophytes
Proboscidean facilitates other herbivores, by digging to water and breaking down pods and other plant matter
Nutrient-rich enough to grow flushes of short-live herbaceous plants after light rain (some ephemerals can set seed in less than two weeks after germination)
Comentarios
In the Namib, Commiphora remains leafless for years at a time.
https://www.inaturalist.org/observations/108934002 and https://www.inaturalist.org/observations/154827197
https://www.inaturalist.org/observations/162151160
https://www.inaturalist.org/observations/161599866
https://www.youtube.com/watch?v=vki-PDxn4fM
My notes on this documentary about the Namib, which I watched on 30 December 2001:
Clear footage of Loxodonta africana in dry riverbeds, particularly the Hoanib (https://en.wikipedia.org/wiki/Hoanib), and also on stony foothills and at an isolated spring-fed pool among the dunes, with Tamarix usneoides (https://www.inaturalist.org/observations/157993166 and https://www.inaturalist.org/observations/162441160) and clumps of Acanthosicyos horrida (https://www.inaturalist.org/observations/162502159 and https://www.inaturalist.org/observations/164262077).
A mature male individual of Loxodonta africana is shown shaking a large tree of Faidherbia albida (https://www.inaturalist.org/observations/48005400) to loosen the reddish ripe pods (https://www.inaturalist.org/observations/148646261 and https://www.inaturalist.org/observations/161839404). Loxodonta africana is also shown ostensibly eating the faeces (particularly the twig content) of its own species.
Footage of Struthio camelus australis, Canis mesomelas mesomelas, Papio ursinus raucana, Antidorcas marsupialis hofmeyri, Oryx gazella (including oryx and elephant in the same frames in the desert landscape), Giraffa giraffa angolensis, and Diceros bicornis bicornis (https://www.inaturalist.org/observations/51613933). In the case of the last species, we see copulation, at the end of which the male falls off, landing heavily on its side.
Footage of S. c. australis, O. gazella, and A. m. hofmeyri drinking.
Diceros bicornis is shown eating a) unpalatable Welwitschia mirabilis (https://www.inaturalist.org/taxa/53821-Welwitschia-mirabilis), as if mainly for the water content, b) greenish stems of Euphorbia damarana (https://www.inaturalist.org/taxa/524175-Euphorbia-damarana), consumed wholesale, and c) specifically the yellowish fruits of E. damarana (which are at least thumbnail size), by means of the semi-prehensile upper lip.
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