Unrecognized Rare species from the southern Cape
It is quite difficult to decide which species should be included, or omitted, from a "Rares" list, largely due to the fact that the concept of rarity is a relative one, as was explained in PAN 9. Generally speaking, a lot of the western Cape taxa might be more threatened by man-made factors and are therefore more likely to be recognized as being rare than are equally rare species elsewhere. However, in less developed areas several taxa may be equally (but naturally) rare in the wild, and because of the lack of immediate threat do not make the Rares lists. I believe that these taxa should be included in Rares lists and that their rarity should be acknowledged. It is possibly high time that we have a workshop on this topic, so that we all have similar concepts of rarity, especially when it comes to the Cape fynbos species.
Here are some rare plant species whose status as published in PAN 9 I disagree with, and my reasons for thinking otherwise.
Jan Vlok, De Rust
Pa longicaulis. This species is now very rare and is largely confined to one large population (ca 500 plants) on private land. Some other small populations still exist, but are badly overgrazed. I believe that this species is under immediate threat of extinction, due to very regular fires to 'improve' the natural vegetation for grazing purposes. Probably fewer than 1 000 plants currently exist in the wild. Some of its habitat should urgently be included in a nature reserve (an unlikely event). [LRD]
Ld dregei. The species grows very slowly and regular fires have extirpated many of its populations. It also has a limited distribution range. [WRD]
Ld olens. I am surprised that you removed this species from the list. Its populations are invaded by very dense stands of Hakea, which must have had an adverse effect. It is still rare even though most of the known populations have now been cleared of alien vegetation. It is restricted to a small area where it is locally common. However, it remains threatened, as adjacent areas are still covered in alien vegetation, which might spread back into the area. [LRD]
Ld orientale. This species is now very rare, with only a few surviving populations in an unprotected area. Many populations were extirpated by afforestation. I only know of a few healthy populations (on the Vanstadensberg), but these are threatened by alien vegetation and possibly by further afforestation. [LRD]
Ld sorocephalodes. This species has suffered recently from too frequent fires and several populations may have been extirpated. I thus believe that it is on the decline. [WRD]
Mi splendidus. Many of the smaller populations of this species have been extirpated in the last decade. Thus it should be moved to a higher category. [WRS]
Pa reflexus. Many of the populations of this species have been extirpated in the last decade by afforestation and/or bad burning practises. Thus it should be moved to a higher category. [LRD]
Pr venusta. With a limited distribution, it is restricted to a specific habitat which has suffered from too frequent fires in the last few decades. Several populations of this species have been extirpated and numbers in the wild are dwindling: it is estimated that fewer than 10 000 mature plants survive in the wild. [WRD]
Ld ericifolium. Several populations still exist, but few occur in nature reserves. This species is locally abundant, but certainly no more than Pr cryophila [LRD] - it should be given an equivalent status. [WBD]
Ld loeriense. Several populations exist, but these are restricted to a relatively small geographical area. [LRD]
Ld nobile: Several populations exist, but the species is restricted to a relatively small area. Many of the populations are being burnt too frequently. [WBD]
Ld rourkei. Several populations, restricted to a relatively small area, exist. I have found several additional healthy populations on the Swartberg, but it is still uncommon enough to deserve a "Rare" status. [LRD]
Ls glabrum. This species is quite uncommon on the Outeniqua and Tsitsikamma mountains. I know the area quite well, but know of fewer than 10 healthy populations. [WRD]
Ls hamatum. This species is restricted to a very small area, where it is locally abundant in the first few years after a fire. Its very limited distribution should make it a good candidate for the Rare category. [LRD]
Ls pluridens. This species is never abundant and restricted to a relatively small area. Several of its populations have been reduced by too frequent fires, and very few occur in protected areas. [LRD]
Ls secundifolium. This species is restricted to narrow ecological band and also has a limited distribution. There is no reason to believe that it is abundant, although it does not seem to be under any immediate man-made threat. [LRD]
Mi chrysanthus. You omitted this species, but it should be regarded as rare due to its limited distribution. It does not seem to be under any immediate threat. [LRD]
Mi pauciflorus. This species appears to be quite abundant, where found, but it has a limited distribution, specialized habitat requirements and many populations are threatened by alien vegetation. [WRS]
Pa esterhuyseniae. This species is never very abundant at any of its locations. It is reasonably well protected, but does not occur over a wide area and seems to be restricted to a very few localities within this distribution range. [WRD]
Pr aristata. In a recent survey by the conservation officer fewer than 5 000 plants could be found in the Klein-Swartberg Mountains. Definitely fewer than 10 000 plants exist in the wild. Thus the species is much rarer than was previously realized. This species has a relatively small distribution, and fortunately it does not seem to be under any immediate threat. [LRS]
Pr convexa. Restricted to a relatively small area and although quite common where found, it is restricted to only a few extensive populations, all in a narrow habitat. Very little is conserved. I am inclined to believe that Pr pityphylla [WRD] and Pr nana [WRD] are equally rare, but have little data for these species. I would like to hear from our western Cape Atlassers if this is true. [WBD]
Pr pruinosa. In a survey by a conservation officer fewer than 500 plants could be found in the Klein-Swartberg Mountains. Fewer than 1000 mature plants probably exist in the wild: this species is thus much rarer than was previously realized. Although having a relatively small distribution, it does not seem to be under any immediate threat. [LRD]
Sp barbigera. A species which is never common within its relatively small distributional range. I know of only a few populations and it seems to have disappeared from some of its previous localities, e.g. Swartberg pass. [WBD]
Pr vogtsiae. This species is restricted to a relatively small area, where most of its habitat has already been destroyed by agriculture. I know of several populations, but am not sure if any more exist, so I should not like to assign it a specific status. [WRD]
Ld cordatum. Although a reasonably widespread species, I know of fewer than 20 populations. These tend to be small (fewer than 100 plants). It occurs on richer soils which are being converted to agriculture. A survey is required to determine its status. [WRD]
Pr nubigena. I do not know much about this species, but it is omitted from your list and I am aware of the fact that it is quite rare. Some of the Drakensberg atlassers might be able to give us a better idea of exactly how rare this species is. [non-Cape, but LRD]
Many thanks for your appraisal of the rarity status of the southern Cape Proteaceae. Hopefully the other conservation agencies will respond in due course. The status of species given in PAN 9 was based on Sue Tansley's paper (Biological Conservation 1989), which was the result of a meeting held in 1986: we therefore expect the status of some species to have changed.
When I assigned Proteaceae species to Rabinowitz categories (PAN 9: 14) I noticed several inconsistencies: The majority of species with distribution ranges less than 2600 km2 (e.g. a circle with a radius of 50 km) in range were categorized by the workshop as "naturally rare", but some were not. Of those which you considered to be "Rare" almost all are localized, mainly in the "Localized distribution, Habitat specialist, Dense population" (LRD) category. Your ranking thus helps to eliminate an inexplicable bias in the existing Rares list.
Only four species in your ranking do not fit into this scheme. These are: Ld eric, Ld nobi, Sp barb and Pr conv. These species have widespread distribution ranges and occur in dense populations. However, inexplicably, they occur in small populations which are far apart from one another (hence their large distribution ranges). Because so few plants exist in only a few populations these species require the rank of naturally rare. These species should form the focus of a more detailed survey in order to determine why they have such a strange pattern of occurrence. And this is yet another facet where atlassers can contribute tremendously to an understanding of protea ecology. Merely by filling in the gaps in our knowledge of species' distribution ranges, atlassers will provide the information needed to understand why these species are distributed so peculiarly. With a bit of thought atlassers may even discover the answer and be able to tell us why these species are rare.
Tony Rebelo, Bellville
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