The flora of southern Africa is not diverse enough to emulate hollies, part 1

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European holly (Ilex aquifolium, https://en.wikipedia.org/wiki/Holly, and see also https://www.inaturalist.org/taxa/516406-Ilex-colchica) and North American holly (Ilex opaca, https://www.inaturalist.org/taxa/60749-Ilex-opaca) are well-known for mainly non-biological reasons.

(Other similar species occur in China, Taiwan, Mongolia, Korea and Japan: https://www.inaturalist.org/taxa/164038-Ilex-cornuta and https://www.inaturalist.org/taxa/708962-Ilex-bioritsensis and https://www.inaturalist.org/taxa/431139-Ilex-pernyi.)

These plants happen to be evergreen and they happen to have cheerfully ruddy fruits, which remain attached during winter (https://ies-ows.jrc.ec.europa.eu/efdac/download/Atlas/pdf/Ilex_aquifolium.pdf).

Hence they have acquired symbolic meaning, around Christmas, when the rest of the vegetation is drab (https://www.researchgate.net/profile/John-Box/publication/266201917_The_festive_ecology_of_holly_ivy_and_mistletoe/links/542999f40cf27e39fa8e63c0/The-festive-ecology-of-holly-ivy-and-mistletoe.pdf).

However, when viewed through the lens of a naturalist, the familiar hollies of the Northern Hemisphere represent a noteworthy combination of adaptive features. This combination has also arisen - owing to evolutionary convergence - under completely different identities in other floras around the world.

The familiar hollies combine the following two adaptations:

• leaf-spines, which discourage nibbling by folivores (https://link.springer.com/article/10.1023/A:1009767931817 and https://academic.oup.com/botlinnean/article/171/3/441/2416188?login=false), and
• fleshy fruit-pulp, which encourages dispersal of seeds by birds (https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/12-0913.1 and https://bioone.org/journals/Madro%C3%B1o/volume-57/issue-1/0024-9637-57.1.1/Invasive-Hollies-span-classgenus-speciesIlex-span-Aquifoliaceae-and-Their-Dispersers/10.3120/0024-9637-57.1.1.short).

Leaf-spinescence is ecologically significant because it tends to occur in plants adapted to nutrient-poor soils, where foliage tends to be so fibrous that it is unpalatable. Such plants tend to be adapted for consumption by combustion rather than by animals.

(For flammability of hollies see https://d1wqtxts1xzle7.cloudfront.net/41212146/00b7d52af709026b27000000.pdf20160115-19908-hc7hac.pdf?1452874087=&response-content-disposition=inline%3B+filename%3DQUANTIFYING_AND_RANKING_THE_FLAMMABILITY.pdf&Expires=1645055085&Signature=FhtCe47Wu31e~IT8e5G5wPQjWGtLX7hn67O3pD7BJQL2CkIPdljRGG2MNgKMQQJGwC7ueQn6ycSbkpGUVdq6Gxnbj8erCgODyNSQRO5ONqDRnu~8ceqBEEW0PmfWoPthZ2RQYQlcYAeOPKq3ZFLIkiwSo4YAMLA3VSb3dSJmNBDO2z6mPsoKevDDD-NLM5a1gAaTfTnLHCWnEukKjTSAwN5r1E1qGecQjYMCaPQxCJZAp8LiHLazCj45fUBTOzYPW5J-ygBr9cv3IB7ffoKHqjEenscYCWaLkOeExpJmo5J-RzVK9-aiu4545bEz3Un~-pKcYGmDLny5CmuMB18f8w__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA and https://www.publish.csiro.au/WF/WF03075.)

Bright-hued, succulent fruit-pulp is ecologically significant because it tends to occur where vegetation is protected from intense wildfires, there is accumulation of organic matter in the soil, and potassium is consequently plentiful (https://www.jstor.org/stable/2844617 and https://www.semanticscholar.org/paper/The-Occurrence-of-Seeds-and-Fruits-Taken-by-Ants-in-Milewski/c8b16a7aa6d2b13a67965de9ab7f4fd9c2ec5a81).

There is obviously some incongruity between nutrient-poverty and potassium-richness, and between flammable and wildfire-free situations.

For this reason, the niches for plants combining leaf-spinescence with fleshy fruits tend to be restricted, and these plants are ecologically noteworthy wherever they occur.

to be continued...

Publicado el febrero 16, 2022 12:14 MAÑANA por milewski