milewski 的日誌
期刊歸檔用於 2023年10月
2023年10月01日
Which is the smallest sexual organism?
(writing in progress)
Does any sexual organism complete its lifecycle in less than 24 hours?
(writing in progress)
2023年10月04日
Gaits and other aspects of locomotion in hippotragin bovids
Estes (1991), on page 116, states the following about postures and locomotion in tribe Hippotragini of family Bovidae:
"The oryxes and addax walk in an amble, as expected. Sables and roans are more variable, cross-walking when going slow and changing to an amble at a quicker walk. Oryxes nod their heads like topis when walking fast, especially the scimitar-horned oryx...The addax throws its wide-hoofed feet slightly sideways to avoid brushing against the opposite limb, but places one foot behind the other, leaving a single line of tracks. The trot is not a regular gait in this tribe but may appear as a transition between walk and gallop, and a style-trot is performed in situations of excitement or alarm. Oryxes have a particularly beautiful flowing trot with a suspension stage during which all feet are off the ground and the head is turned synchronously from side to side...Trotting scimitar-horned oryxes hold their chins raised with horns back...The gallop differs considerably among species. The sable and roan bound higher and flex their legs more than the rest, whereas the addax has a flat gallop with minimal flexing, appearing stiff-kneed. It and the Arabian oryx are considered to be the slowest and clumsiest runners in the tribe, perhaps reflecting their adaptations to sandy substrates. Both have great endurance when traveling on sand...Oryx gazella is probably the fastest and most enduring horse antelope, though less fleet than gazelles or topis. When running at full gallop, the chin is held out so that the horns lie back in line with the neck."
The purpose of this Post is to illustrate as many of these points as possible.
WALKING
There are many photos on the Web of hippotragins walking. This is particularly true for Hippotragus.
So far, I have found no evidence of any walking gait other than an amble.
In the following photos, the amble is diagnosed by the facts that either
- the fore hoof lifts before the hind hoof on the same side has landed, or
- the hind hoof lifts only after the opposite fore hoof has landed.
The action is clearly shown in https://www.pond5.com/stock-footage/item/132191888-majestic-sable-antelope-male-walks-wildwildlife-slow-motion.
Oryx dammah
https://upload.wikimedia.org/wikipedia/commons/7/75/Scimitar_Oryx_Nov09_Werribee.jpg
https://www.alamy.com/scimitar-horned-oryx-oryx-dammah-image348482464.html
https://www.buckvalley.com/hunting-for-scimitar-horned-oryx.html
https://zooinstitutes.com/animals/scimitar-horned-oryx-zoologicka-zahrada-dvur-kralove-8006.html
https://www.alamy.com/stock-photo-scimitar-horned-oryx-oryx-dammah-woburn-safari-park-117908871.html
Oryx leucoryx
https://stock.adobe.com/images/arabische-oryx/739224523?prev_url=detail
https://zooinstitutes.com/animals/arabian-oryx-negev-zoo-112014.html
https://depositphotos.com/photo/oryx-5451367.html
https://depositphotos.com/photo/oryx-16635087.html
https://depositphotos.com/photo/oryx-18814501.html
https://depositphotos.com/photo/oryx-6845558.html
https://stock.adobe.com/images/oryx/1055064?prev_url=detail
https://www.inaturalist.org/observations/108925858
https://www.inaturalist.org/observations/126459790
https://www.inaturalist.org/observations/59677278
https://www.inaturalist.org/observations/1218405
https://www.inaturalist.org/observations/177965278
https://www.inaturalist.org/observations/151272992
https://www.inaturalist.org/observations/149569899
https://www.inaturalist.org/observations/126459796
Hippotragus niger:
https://m.facebook.com/giraffewalks/photos/906091940295842/
https://www.inaturalist.org/observations/153914784
https://www.inaturalist.org/observations/75355905
https://www.inaturalist.org/observations/68297460
https://www.inaturalist.org/observations/34416354
https://www.inaturalist.org/observations/7026088
Hippotragus equinus:
https://www.naturefootage.com/video-clips/PCO190208_0619/roan-antelope-walking-exits
https://www.naturefootage.com/video-clips/PCO190208_0612/roan-antelope-young-male-walking-exits
https://www.inaturalist.org/observations/110614701
https://www.inaturalist.org/observations/144361858
https://www.inaturalist.org/observations/6441967
https://www.inaturalist.org/observations/1242319
https://www.inaturalist.org/observations/6441919
https://www.inaturalist.org/observations/180405972
https://www.inaturalist.org/observations/6183437
https://www.shutterstock.com/image-photo/roan-antelope-savanna-habitat-1744621331
https://www.inaturalist.org/observations/5578805
https://www.shutterstock.com/image-photo/roan-antelope-hippotragus-equinus-savanna-found-1391679617
https://www.inaturalist.org/observations/186394723
https://www.inaturalist.org/observations/5578610
https://www.shutterstock.com/image-photo/roan-antelope-hippotragus-equinus-savanna-found-1391679614
https://www.inaturalist.org/observations/109859169
https://www.inaturalist.org/observations/5221643
https://www.inaturalist.org/observations/109860938
https://www.inaturalist.org/observations/5095524
https://www.inaturalist.org/observations/11028813
https://www.shutterstock.com/image-photo/roan-antelope-hippotragus-equinus-savanna-found-1391679626
https://www.inaturalist.org/observations/5095492
https://www.istockphoto.com/photo/roan-antelope-gm1372038132-441249902?phrase=roan+antelope
https://www.inaturalist.org/observations/4971288
https://www.inaturalist.org/observations/4922939
https://www.inaturalist.org/observations/103681178
https://www.istockphoto.com/photo/roan-antelope-gm1372038132-441249902?phrase=roan+antelope
Addax nasomaculatus:
https://www.youtube.com/watch?v=0WcG532I4is
scroll in https://binderparkzoo.org/animal/addax/
https://vivanicemk.live/product_details/78336358.html
https://fossilrimblog.wordpress.com/2015/01/06/age-matters/
https://www.123rf.com/photo_110255623_addax-walking-in-jebil-national-park-in-tunisia.html
https://www.shutterstock.com/image-photo/addax-walking-jebil-national-park-tunisia-1181753344
https://www.shutterstock.com/image-photo/antelope-addax-pen-zoo-2334248611
https://www.shutterstock.com/image-photo/scimitar-horned-addax-nasomaculatus-144751531
https://www.istockphoto.com/photo/an-antelope-addax-gm1555694218-526772994?phrase=addax+antelope
https://www.istockphoto.com/photo/screwhorn-antelope-gm160142579-17826274?phrase=addax+antelope
https://nhpbs.org/wild/bovidae7.asp
https://creatures-of-the-world.fandom.com/wiki/Addax
Oryx callotis
https://www.inaturalist.org/observations/18775851
Oryx beisa
https://www.inaturalist.org/observations/39632550
https://www.inaturalist.org/observations/36824792
https://www.inaturalist.org/observations/28853647
https://www.inaturalist.org/observations/31507
TROTTING
Hippotragus
https://www.shutterstock.com/image-photo/sable-antelope-bull-trotting-on-sand-495410068
https://www.inaturalist.org/observations/25107302
Oryx
https://www.barhbarhunting.com/scimitar-horned-oryx-antelope
https://www.inaturalist.org/observations/135570419
Oryx leucoryx
https://www.instagram.com/anoopmanikkothphotography/p/CveYdhrPcrQ/
scroll in https://www.arabnews.com/node/1963486/saudi-arabia
GALLOPING/CANTERING
Addax
https://www.dreamstime.com/addax-nasomaculatus-male-running-image171232417
https://www.juzaphoto.com/galleria.php?t=507916&l=en
DISCUSSION
I have yet to find any footage showing the particular actions mentioned by Estes w.r.t. trotting in Oryx.
I am surprised at the sheer number of photos on the Web that happen to show exactly the right moment, in the stride-cycle, for a diagnosis of the amble. This is extreme in the case of H. equinus (29 photos, above).
I suspect that this is not merely coincidence, but rather a consequence - in part - of selection by photographers of the most 'symmetrical' among a sequence of photos all taken within a few seconds.
2023年10月05日
Ecology of Malolotja Nature Reserve in Eswatini, on the eastern escarpment of southern Africa
@richardgill @andrew_hankey @tonyrebelo @jeremygilmore @kyle_campbell1 @troos @botaneek @pieterwinter @nicky @adriaan_grobler @wynand_uys @craigpeter @charles_stirton @sedgesrock @kenneth_oberlander @rion_c @ricky_taylor @bartwursten @geoffnichols @katebraunsd @suemilton-dean @graham_g
Malolotja Nature Reserve (https://en.wikipedia.org/wiki/Malolotja_National_Park and https://en.wikipedia.org/wiki/Songimvelo-Malolotja_Transfrontier_Conservation_Area and https://jonnyhale.co.uk/guides/swaziland-travel-guide/malolotja-nature-reserve-swaziland/ and http://www.traveladventures.org/continents/africa/malolotja-national-park08.html) lies along the northwestern border of Eswatini (https://en.wikipedia.org/wiki/Eswatini).
It is ecologically similar to the eastern edge of the Highveld (https://en.wikipedia.org/wiki/Highveld), which - strictly speaking - lies several hundred km to the west.
The following description of this conservation area is based on an unpublished report written by Ken L Tinley in 1978, in support of a proposal to upgrade the nature reserve to the status of national park.
GENERAL SETTING
Imagine yourself near Forbes Reef (https://www.mindat.org/loc-233780.html), on the ridge dividing the valleys of the Inkomati (https://en.wikipedia.org/wiki/Komati_River) and Mbuluzi (https://en.wikipedia.org/wiki/Mbuluzi_River) streams.
You view the landscape to the north, which falls within Malolotja Nature Reserve. More specifically, you view the confluence of the ravines of the Inkomati and the Malolotja streams.
The skyline, from left to right, consists of the Silotwane range, with the Shokohla range in the distance; then the Makonjwa range, rising to the blunt peak of Josefskop (1757 m a.s.l.); then the Emlembe range, with its even blunter peak at 1852 m a.s.l. The middle distance consists of steep, treeless slopes. Trees are confined to drainage lines and the tor-fields traversing the crests of the low hills in the foreground, a few kilometres from where you stand.
VEGETATION IN RELATION TO LANDFORMS
Catena on Ngwenya range, in the south-western sector of the Park, near the iron ore mine (https://whc.unesco.org/en/tentativelists/5421/):
- at highest altitudes, treeless grassland
- on upper slopes, low savanna of Protea (https://www.inaturalist.org/taxa/521002-Protea-roupelliae), on latosols (https://en.wikipedia.org/wiki/Latosol), with or without weathered tors ((https://www.dictionary.com/browse/tor))
- on mid-slopes, treeless grassland on shallow soil (held together by root-mats of grasses) over angular subsurface stones, which include abundant hand-axe implements dating to the stone age
- on lower slopes, treeless grassland on colluvial soils, lacking the subsurface stones
Catena on granite in eastern sector of the Park:
- at highest altitudes, treeless grassland
- on upper slopes, patches of thicket on tor-fields of Bornhardt cores (https://en.wikipedia.org/wiki/Bornhardt)
- on mid-slopes and lower slopes, treeless grassland on pink to red, sandy latosol. The surface is extremely resistant to erosion when bared, especially in areas influenced by dolerite. The subsoil deeper than 1 m grades into a layer of friable, leached kaolinite, which erodes extremely rapidly if exposed
Catena on eastern slopes of Ngwenya and Silotwane ranges:
- at highest altitudes, treeless grassland traversed by woody vegetation (Englerophytum-Pterocarpus-Faurea) on tor-ridges (https://www.inaturalist.org/taxa/468538-Englerophytum-magalismontanum, https://www.inaturalist.org/observations/21694030)
- on upper slopes, thickets on sink-holes. Elsewhere, patches of marsh on peat, drained by incised streams bearing Syzygium cordatum, which invades as erosion proceeds upslope into the marshes (https://www.inaturalist.org/taxa/338719-Syzygium-cordatum)
- on lower slopes, tree-ferns on incised pipe-drainage
Catena in ravines:
- at highest altitudes, woody vegetation on tor-ridges
- on upper slopes, Xerophyta and Aloe on rock faces (https://www.inaturalist.org/taxa/601609-Xerophyta-retinervis-retinervis)
- on midslopes, thicket on talus and rocky outcrops
- on lower slopes, scattered tree-cycads (Encephalartos paucidentatus, https://www.inaturalist.org/taxa/135949-Encephalartos-paucidentatus)
- in drainage lines, narrow tracts of riverine forest of Breonadia, Anthocleista, Syzygium (https://www.inaturalist.org/taxa/429244-Breonadia-salicina, https://www.inaturalist.org/taxa/132972-Anthocleista-grandiflora)
Floors of ravines:
- marshes and peat-bogs on organic hydromorphic soils, built up by fen peat, produced by hygrophilous sedges and grasses
SOILS
Please see http://eswatinibiodiversity.com/nature_reserves/malolotja_geomorphology.asp
Over most of Malolotja Nature Reserve, the bedrock consists of quartzites and conglomerates. Granites occur along the eastern sector, near the main road to Piggs Peak (https://en.wikipedia.org/wiki/Piggs_Peak). The northern Makonjwa valley is formed on phyllites, greywackes and cherts. Intercalated with these are small outcrops of serpentinites and schists.
All these rocks weather to a mainly sandy texture. The main soils in Malolotja Nature Reserve are yellow and red ferralitic soils (https://en.wikipedia.org/wiki/Ferrallitisation), mostly of a sandy or sandy clay texture.
Piercing the above metamorphic rocks are dolerite dykes of various dimensions. Here, the soils are red latosols, more loamy than those described above.
GENERAL PATTERNS IN THE VEGETATION
As interpreted by Tinley (1978):
Treeless grassland in Malolotja Nature Reserve is generally associated with either
- poor drainage, or
- latosols, where any seasonal waterlogging in summer is followed by edaphic drought in winter.
Woody vegetation is generally associated with moist but well-drained (aerobic) sites and substrates.
Thus,
- treeless grassland predominates over all aspects of the rounded terrain of hills and valleys, on substrates with either seasonal waterlogging or extreme seasonal variation in moisture, and
- thicket/forest, by contrast, is confined to substrates with moderate moisture, viz. the incised heads of valleys, rock outcrops, sinkholes, and streambanks.
"Most of the thicket/forest habitats which occur on the valley sides are in relatively fresh donga incisions of old valley head vleis, indicating that they are young developing communities, and not relics as is prevalently thought. Although the sharp edges of most thicket/forest habitats is due to the singeing by annual fires, their spatial patterns are determined primarily by perch-based dispersion of seeds and by soil moisture balance" (Tinley 1978).
According to the vegetation classification system of Acocks (https://archive.org/details/veldtypesofsouth00acoc):
Most of Malolotja Nature Reserve is covered by the Piet Retief Sourveld division (Acocks Type 63) of the Highveld Grassland formation.
The second-largest area is occupied by the Northeastern Mountain Sourveld (Acocks Type 8), on lower parts of the upland in the escarpment zone,
The smallest area is occupied by Lowveld Sour Bushveld (Acocks Type 9), confined to the main river valleys and the tor-field outcrops.
TYPES OF TREELESS GRASSLAND
Highest altitudes:
Most of the terrain in Malolotja Nature Reserve is below 1830 m a.s.l. Only the highest parts of the Ngwenya range are likely to provide habitat for the short grasses of montane grassland. e.g. Festuca (https://www.inaturalist.org/taxa/585885-Festuca-scabra and https://www.inaturalist.org/taxa/585881-Festuca-costata) and Merxmuellera (https://www.inaturalist.org/observations?place_id=6986&taxon_id=577222&view=species)
Medium altitudes:
The main type of treeless grassland in Malolotja Nature Reserve is the Piet Retief type (Acocks type 63). This vegetation is usually < 50 cm high, the flowering stalks reaching 80 cm.
These grasslands are dotted by termitaria, mainly of Trinervitermes (https://www.inaturalist.org/observations?place_id=any&taxon_id=567388&view=species).
These termitaria form relatively nutrient-rich microsites in an otherwise nutrient-poor landform, and feature small patches of the lawn-forming grass Cynodon dactylon (https://www.inaturalist.org/taxa/58371-Cynodon-dactylon).
Where there is continual grazing and the termitaria are eroded, the resulting flattened patches support enlarged lawns of C. dactylon, with diameters up to 7-10 m.
Typical grasses include:
- Alloteropsis semialata (https://www.inaturalist.org/taxa/369723-Alloteropsis-semialata)
- Cenchrus alopecuroides (https://www.inaturalist.org/taxa/1030051-Cenchrus-alopecuroides)
- Diheteropogon amplectens (https://www.inaturalist.org/taxa/506862-Diheteropogon-amplectens)
- Elionurus muticus (https://www.inaturalist.org/taxa/279598-Elionurus-muticus)
- Eragrostis racemosa (https://www.inaturalist.org/taxa/584580-Eragrostis-racemosa)
- Harpochloa falx (https://www.inaturalist.org/taxa/586759-Harpochloa-falx)
- Koeleria capensis (https://www.inaturalist.org/taxa/578668-Koeleria-capensis)
- Loudetia simplex (https://www.inaturalist.org/taxa/489495-Loudetia-simplex)
- Microchloa altera (https://www.inaturalist.org/taxa/703849-Microchloa-altera)
- Microchloa caffra (https://www.inaturalist.org/taxa/589984-Microchloa-caffra)
- Monocymbium ceresiforme (https://www.inaturalist.org/taxa/506886-Monocymbium-ceresiiforme)
- Themeda triandra (https://www.inaturalist.org/taxa/208571-Themeda-triandra)
- Tristachya leucothrix (https://www.inaturalist.org/taxa/595724-Tristachya-leucothrix)
- Urelytrum agropyroides (https://www.inaturalist.org/taxa/595883-Urelytrum-agropyroides)
- Urochloa serrata (https://www.inaturalist.org/taxa/866976-Urochloa-serrata)
Lowest altitudes:
Patches of tall treeless grassland occur in moist sites on the floors and sides of valleys. These consist of
- Andropogon (https://www.inaturalist.org/observations?place_id=7478&taxon_id=71966&view=species),
- Setaria (https://www.inaturalist.org/observations?place_id=7478&taxon_id=50055&view=species), and
- Hyparrhenia (https://www.inaturalist.org/observations?place_id=7478&taxon_id=71939&view=species).
All these grasslands are subjected to annual fires. Some areas are also burnt in mid-summer, i.e. twice per year.
VEGETATION ON ROCK-FACES
Large, bare rock-faces occur mainly in the eastern sector, where exfoliating domes of granite occur.
In these and other areas of bare rock, a large variety of herbaceous and woody plants occurs in the joints and crevices. Typical examples include Xerophyta and Aloe, and the striking, red-flowered Streptocarpus dunnii (https://www.inaturalist.org/taxa/489705-Streptocarpus-dunnii).
Lower down in some valleys, tree cycads (Encephalartos paucidentatus), reaching heights of 6-7 m, occur in the crevices of otherwise bare (except for lichens) rock-faces.
TYPES OF SAVANNA
Savannas occur
- at high altitudes (Protea rouppelliae up to 3 m high),
- on tor-fields, at medium to low altitudes and
- in valleys.
Savanna on tor-fields includes the following trees, spaced more than three crown-diameters apart:
- Englerophytum magaliesmontanum
- Ekebergia pterophylla (https://www.inaturalist.org/taxa/584385-Ekebergia-pterophylla)
- Faurea spp. (https://www.inaturalist.org/observations?place_id=any&taxon_id=183417&view=species)
- Protea spp. (https://www.inaturalist.org/observations?place_id=7143&taxon_id=129714&view=species)
- Pterocarpus angolensis (https://www.inaturalist.org/taxa/340243-Pterocarpus-angolensis)
Savanna in valleys contains, e.g.
- Vachellia sieberiana (https://www.inaturalist.org/taxa/559085-Vachellia-sieberiana)
- Vachellia natalitia (https://www.inaturalist.org/taxa/595955-Vachellia-natalitia)
- Euphorbia ingens (https://www.inaturalist.org/taxa/334379-Euphorbia-ingens)
- Sclerocarya caffra (https://www.inaturalist.org/taxa/181936-Sclerocarya-caffra)
- Bauhinia galpinii (https://www.inaturalist.org/taxa/159197-Bauhinia-galpinii)
TYPES OF THICKET/FOREST
Riverine forest:
Narrow tracts of streambank forest occur in a few areas, e.g. the gorge below Malolotja Falls. These consist mainly of tall trees of Breonadia salicina (https://www.inaturalist.org/taxa/159197-Bauhinia-galpinii).
Additional spp. of trees include
- Anthocleista grandiflora
- Syzygium cordatum (https://www.inaturalist.org/taxa/338719-Syzygium-cordatum)
- Ficus sycomorus (https://www.inaturalist.org/taxa/340164-Ficus-sycomorus)
- Rauvolfia caffra (https://www.inaturalist.org/taxa/133184-Rauvolfia-caffra)
In the headward-eroding streambeds are lines of S. cordatum or tree-ferns (Cyathea dregei, https://www.inaturalist.org/taxa/320739-Cyathea-dregei). In the lower valleys, above the level of the riverine trees, there are thickets, formed by scandent Senegalia ataxacantha (https://www.inaturalist.org/taxa/567417-Senegalia-ataxacantha) and B. galpinii.
Thicket on rock outcrops:
This forms patches, in which typical spp. include:
- Apodytes dimidiata (https://www.inaturalist.org/taxa/489301-Apodytes-dimidiata)
- Buddleia spp. (https://www.inaturalist.org/taxa/211103-Buddleja-salviifolia and https://www.inaturalist.org/taxa/581467-Buddleja-pulchella)
- Cephalanthus natalensis (https://www.inaturalist.org/taxa/581875-Cephalanthus-natalensis)
- Cussonia spicata (https://www.inaturalist.org/taxa/143538-Cussonia-spicata)
- Diospyros whyteana (https://www.inaturalist.org/taxa/541445-Diospyros-whyteana)
- Ficus spp. (https://www.inaturalist.org/observations?place_id=7143&taxon_id=50999&view=species)
- Halleria lucida (https://www.inaturalist.org/taxa/402272-Halleria-lucida)
- Kiggelaria africana (https://www.inaturalist.org/taxa/119178-Kiggelaria-africana)
- Maesa lanceolata (https://www.inaturalist.org/taxa/133587-Maesa-lanceolata)
- Maytenus acuminata (https://www.inaturalist.org/taxa/557508-Maytenus-acuminata)
- Myrsine africana (https://www.inaturalist.org/taxa/70260-Myrsine-africana)
- Nuxia congesta (https://www.inaturalist.org/taxa/185371-Nuxia-congesta)
- Osyris lanceolata (https://www.inaturalist.org/taxa/342039-Osyris-lanceolata)
- Podocarpus latifolius (https://www.inaturalist.org/taxa/132930-Podocarpus-latifolius)
- Pittosporum viridiflorum (https://www.inaturalist.org/taxa/166935-Pittosporum-viridiflorum)
- Psychotria capensis (https://www.inaturalist.org/taxa/431505-Psychotria-capensis)
- Pterocelastrus spp. (https://www.inaturalist.org/observations?place_id=7143&taxon_id=526209&view=species)
- Rapanea melanophloeos (https://www.inaturalist.org/taxa/578244-Rapanea-melanophloeos)
Thicket on sinkholes:
Many of the spp. listed above also occur where the soil surface has collapsed above underground pipe drainages. Here, one of the first colonisers is the tree-fern, Cyathea dregei.
Thicket on termite mounds:
A few small patches of thicket occur on mounds of Macrotermes (https://www.inaturalist.org/observations?place_id=7143&taxon_id=346639&view=species), on the lower slopes of the Malolotja and Inkomati drainages. Their species-composition is unrecorded.
Southern afrotemperate thicket (allied to https://en.wikipedia.org/wiki/Southern_Afrotemperate_Forest) :
This type is floristically similar to thicket on rock outcrops. It is restricted to a few small patches, occurring
- in west-facing ravines of the Ngwenya range, and
- at higher altitudes, at the heads of valleys on east-facing aspects of the Makonjwa range, in the north of Malolotja Nature Reserve.
Additional spp. include
- Syzygium gerrardii (https://www.inaturalist.org/taxa/595101-Syzygium-gerrardii)
- Neocussonia umbellifera (https://www.inaturalist.org/taxa/1269678-Neocussonia-umbellifera)
- Combretum kraussii (https://www.inaturalist.org/taxa/135386-Combretum-kraussii)
- Xymalos monospora (https://www.inaturalist.org/taxa/132925-Xymalos-monospora)
- Curtisia dentata (https://www.inaturalist.org/taxa/490221-Curtisia-dentata)
- Zanthoxylum davyi (https://www.inaturalist.org/taxa/469304-Zanthoxylum-davyi)
- Prunus africana (https://www.inaturalist.org/taxa/435322-Prunus-africana)
- Cassipourea malosana (https://www.inaturalist.org/taxa/342720-Cassipourea-malosana)
AQUATIC VEGETATION
The most extensive areas of marsh and acidic bog, remaining intact, are on then southern margin of Malolotja Nature Reserve.
Two large areas of valley sedge peat occur, viz.
- in the headwaters of the Malolotja river/stream, and
- at the source of the Mbuluzi river/stream.
These herbaceous bogs support a large variety of plants, among which sedges, orchids, and lilies are abundant.
Typical of the bogs is a flowering sequence, in which each species, or group of species, shows a temporary visual dominance.
PASTURE VALUE OF TREELESS GRASSLANDS
All the grasslands in Malolotja Nature Reserve are poor as pastures. This is because the soils are leached and nutrient-poor, producing fibrous, protein-poor plant matter.
The grasses are palatable to grazers only during the growing season, which occurs during the rainy summers and lasts for 3-4 months. Instead of being eaten, the grasses are consumed largely by fire.
The carrying capacity, for livestock or wild ungulates, is estimated to be one stock unit (454 kg) per hectare, and this applies only to the 4-5 months of summer.
Tinley (1978) states:
"A most important finding of long-term pasture experiments, is that mowed veld yields up to eight times as much herbage as burnt veld. In sourveld the period of palatability is extended by mowing in midsummer...Ideally, therefore, as much mowing as possible should be undertaken in preference to burning."
LARGE HERBIVORES
Tinley (1978) pointed out that perhaps the wild ungulate most suited to reintroduction in Malolotja Nature Reserve was the blesbok (Damaliscus pygargus phillipsi).
This has been borne out by the local viability of the blesbok, proven over the ensuing 45 years (https://www.inaturalist.org/observations?nelat=-26.1397456197085&nelng=31.11894708029149&place_id=any&swlat=-26.1424435802915&swlng=31.1162491197085&taxon_id=152870).
The blesbok is particularly adapted to the nutrient-poor grasslands of the Highveld, by virtue of its relatively small body size and seasonally frugal metabolism.
With respect to the springbok (Antidorcas marsupialis marsupialis, https://www.inaturalist.org/taxa/42283-Antidorcas-marsupialis), Tinley (1978) wrote:
"We are assured by Mr Ted Reilly that springbok were recorded from the western sector of Swaziland in the past. However, the remnant springbok populations in the adjacent eastern Highveld of the Transvaal are all associated with the alkaline and saline sweetveld shortgrass pastures occurring round the margins of the isolated pan systems found in this region. Springbok do survive in sourveld, but as the animals in Mlilwane and the Krugersdorp Lion Park show, their physical condition is poor almost throughout the year, and in these areas they feed almost exclusively on the sweetveld patches of kweek, Cynodon, growing on termite mounds."
ACKNOWLEDGMENT
It is Ken L Tinley, not I, who performed the fieldwork for this report. My role has been to bring a long unpublished piece of work to light, by means of a complete edit and nearly-complete rewriting. Because Tinley submitted his report to the government of the then Swaziland 45 years ago, his work risks vanishing from the public record. Furthermore, the paucity of observations from Malolotja Nature Reserve in iNaturalist shows that this area has been neglected/underplayed by naturalists. I trust that this Post will help to renew interest in a reserve which failed to be raised to the status of national park, but deserves appreciation.
2023年10月07日
A record, for posterity, of the floristic composition of strandveld at Kommetjie-Scarborough, Cape Peninsula, Western Cape, South Africa
@tonyrebelo @jeremygilmore @troos @botaneek @vynbos @daverichardson @yvettevanwijk1941 @cmerry @rion_c @dianastuder @sedgesrock @charles_stirton @kenneth_oberlander
I have before me an unpublished report, about 30 years old, written by D M Mann, then a student at the University of Cape Town (https://en.wikipedia.org/wiki/University_of_Cape_Town).
It is titled 'Dynamic dune communities: their structure and the threats that face them', and documents the flora of certain small, coastal remnants of indigenous vegetation on the outskirts of the metropolitan area of Cape Town (https://en.wikipedia.org/wiki/Cape_Town).
The following show the general scenery:
https://www.gettyimages.co.uk/detail/photo/long-beach-with-the-village-kommetjie-in-the-royalty-free-image/1033726788?adppopup=true
https://en.wikipedia.org/wiki/Scarborough,_Western_Cape#/media/File:Scarborough_Western_Cape_Coastline_and_City_View.jpg
At the time, these remnants were beset by several degrading influences, particularly
- invasion by the Australian small trees, Acacia cyclops (https://www.inaturalist.org/taxa/75249-Acacia-cyclops) and Acacia saligna (https://www.inaturalist.org/taxa/75255-Acacia-saligna), and
- recreational trampling by Homo sapiens, resulting in damage to plants by windblown sand.
However, the vegetation remained intact enough that D M Mann was able to find a total of 27 sample plots (each 5 m X 10 m), in which to record the composition of the undisturbed vegetation, naturally exempt from wildfire, called 'strandveld' (https://en.wikipedia.org/wiki/Cape_Flats_Dune_Strandveld#:~:text=Wolfgat%20Nature%20Reserve-,Flora,Olifantsbos%2C%20Macassar%20and%20Gordons%20Bay.).
My interest in what might otherwise be forgotten as merely a small, unpublished study is based on the following perspective.
Unlike fynbos (https://en.wikipedia.org/wiki/Fynbos), which is ecologically fragile, strandveld is arguably resilient from various forms of disturbance. Therefore, strandveld may have long-term prospects for conservation in suburban settings. Even the problem of usurpation by Australian acacias may, in time, tend to resolve itself as the introduced plants integrate into the flora and become increasingly subject to damage by invertebrates.
Therefore, it may prove valuable to have a permanent record of the original floristic composition.
The study area was the coastal strip between Kommetjie (https://en.wikipedia.org/wiki/Kommetjie) and Scarborough (https://en.wikipedia.org/wiki/Scarborough,_Western_Cape), including
- Soetwater Nature Reserve (https://www.capebirdclub.org.za/event/outing-rondevlei-nature-reserve-leader-merle-chalton-november-2020-2/ and https://m.facebook.com/profile.php?id=1101903723188071&_rdr and https://www.capebirdclub.org.za/portfolio/soetwater-enviro-centre-03-november-2020/) and
- Witsand (https://www.google.com.au/maps/@-34.144546,18.3396759,12.99z?entry=ttu)
The substrate in the sample-plots is sand, derived from the beach rather than sandstone. This sand is partly calcareous, containing calcitic grains derived from the fragmented shells of marine organisms. The pH varied from 8 (alkaline) to 7 (neutral, where organic matter has accumulated under large, clonal shrubs of Sideroxylon inerme).
The strandveld sampled ranged from stands of low shrubs, including littoral elements associated with the edge of the beach, to stands of S. inerme, in which there were few additional plant species other than the liane Cynanchum obtusifolium (https://www.inaturalist.org/observations/36974049) - which in the study area occurred exclusively on S. inerme.
D M Mann recorded the cover-abundance of each species in each of the sample plots, according to the percentage categories used in the Braun-Blanquet system (https://link.springer.com/article/10.1007/bf01866672). However, I will not attempt to report the data here, at that level of detail.
RESULTS
Taking all of the sample plots collectively, the indigenous flora was as follows.
AIZOACEAE
Carpobrotus edulis (https://www.inaturalist.org/taxa/49322-Carpobrotus-edulis)
Jordaaniella dubia (https://www.inaturalist.org/taxa/532788-Jordaaniella-dubia)
Ruschia macowanii (https://www.inaturalist.org/taxa/491674-Ruschia-macowanii)
Tetragonia fruticosa (https://www.inaturalist.org/taxa/528778-Tetragonia-fruticosa)
AMARYLLIDACEAE
Brunsvigia orientalis (https://www.inaturalist.org/taxa/132796-Brunsvigia-orientalis)
ANACARDIACEAE
Searsia glauca (https://www.inaturalist.org/taxa/564119-Searsia-glauca)
Searsia laevigata (https://www.inaturalist.org/taxa/493489-Searsia-laevigata)
Searsia lucida (https://www.inaturalist.org/taxa/593894-Searsia-lucida)
ASCLEPIADACEAE
Cynanchum africanum (https://www.inaturalist.org/taxa/119577-Cynanchum-africanum)
Cynanchum obtusifolium (https://www.inaturalist.org/taxa/583200-Cynanchum-obtusifolium)
ASPARAGACEAE
Asparagus aethiopicus (https://www.inaturalist.org/taxa/75603-Asparagus-aethiopicus)
Asparagus lignosus (https://www.inaturalist.org/taxa/505800-Asparagus-lignosus)
ASTERACEAE
Osteospermum incanum (https://www.inaturalist.org/taxa/596722-Osteospermum-incanum)
Osteospermum moniliferum (https://www.inaturalist.org/taxa/404420-Osteospermum-moniliferum)
Chrysocoma coma-aurea (https://www.inaturalist.org/taxa/129068-Chrysocoma-coma-aurea)
Cinereria geifolia (https://www.inaturalist.org/taxa/582265-Cineraria-geifolia)
Eriocephalus africanus (https://www.inaturalist.org/taxa/430981-Eriocephalus-africanus)
Helichrysum crispum (https://www.inaturalist.org/taxa/586894-Helichrysum-crispum)
Helichrysum dasyanthum (https://www.inaturalist.org/taxa/545839-Helichrysum-dasyanthum)
Helichrysum litorale (https://www.inaturalist.org/taxa/570762-Helichrysum-litorale)
Helichrysum niveum (https://www.inaturalist.org/taxa/586980-Helichrysum-niveum)
Ifloga repens (https://www.inaturalist.org/taxa/1391564-Ifloga-repens)
Metalasia muricata (https://www.inaturalist.org/taxa/527592-Metalasia-muricata)
Othonna coronopifolia (https://www.inaturalist.org/taxa/591071-Othonna-coronopifolia)
Senecio elegans (https://www.inaturalist.org/taxa/79044-Senecio-elegans)
Senecio arniciflorus (https://www.inaturalist.org/taxa/594188-Senecio-arniciflorus)
CAMPANULACEAE
Wahlenbergia tenella (https://www.inaturalist.org/taxa/596191-Wahlenbergia-tenella)
CELASTRACEAE
Cassine peragua (https://www.inaturalist.org/taxa/527633-Cassine-peragua)
Gymnosporia buxifolia (https://www.inaturalist.org/taxa/586670-Gymnosporia-buxifolia)
Pterocelastrus tricuspidatus (https://www.inaturalist.org/taxa/526208-Pterocelastrus-tricuspidatus)
Robsonodendron maritimum (https://www.inaturalist.org/taxa/593220-Robsonodendron-maritimum)
CRASSULACEAE
Cotyledon orbiculata (https://www.inaturalist.org/taxa/76462-Cotyledon-orbiculata)
Crassula tetragona (https://www.inaturalist.org/taxa/76467-Crassula-tetragona)
CUCURBITACEAE
Kedrostis nana (https://www.inaturalist.org/taxa/431200-Kedrostis-nana)
CYPERACEAE
Ficinia filiformis (https://www.inaturalist.org/taxa/585915-Ficinia-filiformis)
Ficinia ramosissima (https://www.inaturalist.org/taxa/569401-Ficinia-ramosissima)
Ficinia trichodes (https://www.inaturalist.org/taxa/585949-Ficinia-trichodes)
Schoenus cuspidatus (https://www.inaturalist.org/taxa/894562-Schoenus-cuspidatus)
Tetraria capillacea (https://www.inaturalist.org/taxa/595254-Tetraria-capillacea)
EBENACEAE
Euclea racemosa (https://www.inaturalist.org/taxa/526223-Euclea-racemosa)
GENTIANACEAE
Chironia baccifera (https://www.inaturalist.org/taxa/426224-Chironia-baccifera)
FABACEAE
Aspalathus hispida (https://www.inaturalist.org/taxa/580489-Aspalathus-hispida)
Indigofera brachystachya (https://www.inaturalist.org/taxa/587756-Indigofera-brachystachya)
Psoralea fruticans (https://www.inaturalist.org/taxa/1434303-Psoralea-fruticans)
LAMIACEAE
Salvia aurea (https://www.inaturalist.org/taxa/380967-Salvia-aurea)
LAURACEAE
Cassytha ciliolata (https://www.inaturalist.org/taxa/461729-Cassytha-ciliolata)
MYRICACEAE
Myrica cordifolia (https://www.inaturalist.org/taxa/527591-Morella-cordifolia)
MYRSINACEAE
Myrsine africana (https://www.inaturalist.org/taxa/70260-Myrsine-africana)
OLEACEAE
Chionanthus foveolatus (https://www.inaturalist.org/taxa/582167-Chionanthus-foveolatus)
Olea exasperata (https://www.inaturalist.org/taxa/578517-Olea-exasperata)
PLUMBAGINACEAE
Limonium scabrum (https://www.inaturalist.org/taxa/426220-Limonium-scabrum)
POACEAE
Ehrharta villosa (https://www.inaturalist.org/taxa/409471-Ehrharta-villosa)
Pentameris barbata (https://www.inaturalist.org/taxa/591740-Pentameris-barbata)
Tribolium hispidum (https://www.inaturalist.org/taxa/595630-Tribolium-hispidum)
POLYGALACEAE
Muraltia spinosa (https://www.inaturalist.org/taxa/526214-Muraltia-spinosa)
Polygala myrtifolia (https://www.inaturalist.org/taxa/181610-Polygala-myrtifolia)
RANUNCULACEAE
Knowltonia capensis (https://www.inaturalist.org/taxa/568954-Knowltonia-capensis)
RESTIONACEAE
Restio eleocharis (https://www.inaturalist.org/taxa/527597-Restio-eleocharis)
Restio leptoclados (https://www.inaturalist.org/taxa/703947-Restio-leptoclados)
RHAMNACEAE
Phylica ericoides (https://www.inaturalist.org/taxa/470408-Phylica-ericoides)
ROSACEAE
Cliffortia obcordata (https://www.inaturalist.org/taxa/582413-Cliffortia-obcordata)
RUBIACEAE
Galium tomentosum (https://www.inaturalist.org/taxa/586115-Galium-tomentosum)
RUTACEAE
Agathosma imbricata (https://www.inaturalist.org/taxa/568505-Agathosma-imbricata)
SANTALACEAE
Colpoon compressum (https://www.inaturalist.org/taxa/527438-Colpoon-compressum)
Thesium fragile (https://www.inaturalist.org/taxa/1180365-Thesium-fragile)
SAPOTACEAE
Sideroxylon inerme (https://www.inaturalist.org/taxa/362175-Sideroxylon-inerme)
SCROPHULARIACEAE
Chaenostoma hispidum (https://www.inaturalist.org/taxa/570499-Chaenostoma-hispidum)
Lyperia tristis (https://www.inaturalist.org/taxa/589507-Lyperia-tristis)
THYMELAEACEAE
Passerina paleacea (https://www.inaturalist.org/taxa/591427-Passerina-paleacea)
VISCACEAE
Viscum capense (https://www.inaturalist.org/taxa/119585-Viscum-capense)
ZYGOPHYLLACEAE
Roepera flexuosa (https://www.inaturalist.org/taxa/560274-Roepera-flexuosa)
2023年10月08日
Australia is a land of reptiles, but not particularly large ones, part 1: turtles, tortoises, lizards, and snakes
@herping_with_berks @colin25 @tyroneping @alexanderr @tonyrebelo @jeremygilmore @cvanderson @calebcam @tom-kirschey @herping_with_sean @bushboy @nwatinyoka @m_burger @viperidae4ever @rion_c @leo_du_toit @wolfgang_wuster @daniel_liepack @ruan_stander @johannesvanrooyen @jouberth @michael_jacobi @ockertvs @snakesrcool @asimakis_patitsas @zdunek_herp @max_tibby @patrick_campbell @halvard_midtun @grahamarmstrong @charliev @mattcampbellaus @ritt @ptexis @adammyates @ethan241 @albertogn
Australia seems to be a land of reptiles.
For example,
- nowhere else can claim more than 45 species coexisting in one hectare of semi-desert (https://www.jstor.org/stable/2462175 and http://www.zo.utexas.edu/faculty/pianka/Rarity.html and https://www.jstor.org/stable/j.ctt1m3nzwt) ;
- the longest lizard ever known, viz. the extinct giant varanid, Megalania prisca (https://en.wikipedia.org/wiki/Megalania), lived on the Darling Downs (https://en.wikipedia.org/wiki/Darling_Downs) in Queensland in the Pleistocene;
- the inland taipan (Oxyuranus microlepidotus) is reputed to have the strongest venom on Earth (https://en.wikipedia.org/wiki/Inland_taipan).
Why is it, then, that
- several niches for reptiles are oddly empty in Australia, and
- the largest living reptiles here are generally smaller than those elsewhere?
It is body mass - not length - that is most important when assessing the size of animals.
Body mass - although seldom measured - determines the energy consumption of a species and its likely demands from, and effects on, an ecosystem.
Length is a particularly poor indicator of body size in reptiles, which vary from linear snakes to hemispherical tortoises.
Readers may ho-hum to hear that the saltwater crocodile (Crocodylus porosus, https://www.inaturalist.org/taxa/26068-Crocodylus-porosus) weighs more than the scrub python (Simalia kinghorni, https://www.inaturalist.org/observations?place_id=any&taxon_id=540202&view=species) of similar extreme length of 6 metres. However, the news that this difference is 30-fold may raise an eyebrow.
This principle applies also within crocodilians, snakes, and lizards, in which the girth of the body is as important for body mass as is the total length.
Bulk is critical to reptiles, partly because it greatly affects the rate of reproduction. The greater the body mass of females, the more eggs or live-young are produced at a time.
Females are, in this context, the more important sex. It takes only one male individual to inseminate many female individuals. Furthermore, some reptiles are parthogenetic, making males redundant. Although particularly large males tend to command attention, they do not necessarily contribute much to the overall energetics of the species.
It is females that are immediately indispensible for survival.
Reptiles provoke exaggeration (when reporting data), macho, and hyperbole (when interpreting data), even among the educated.
Therefore, I sought out well-documented records of maximum body sizes. These are remarkably few for females.
I have tried to avoid other pitfalls. For example,
- reptiles may continue to grow long after reaching adulthood, and
- body masses may be doubled when large prey is swallowed whole.
Bearing these caveats in mind, how does Australia compare with other southern continents at the same latitudes?
TESTUDINES (https://en.wikipedia.org/wiki/Turtle)
The living fauna of testudines in Australia falls short in two respects.
Firstly, this is the only inhabited continent that lacks any land tortoise. By contrast, tortoises weighing more than 30 kg are widespread in southern Africa (Stigmochelys pardalis, https://www.inaturalist.org/taxa/40092-Stigmochelys-pardalis) and South America (Chelonoidis denticulatus, https://www.inaturalist.org/taxa/539451-Chelonoidis-denticulatus), at similar latitudes.
Secondly, the freshwater testudines of Australia are limited in body size. The largest species is Carettochelys insculpta, (https://www.inaturalist.org/taxa/39536-Carettochelys-insculpta) of tropical Australia, which can reach 22.5 kg, and lays no more than 30 eggs at a time.
By contrast,
- Trionyx triunguis (https://www.inaturalist.org/taxa/39553-Trionyx-triunguis) of Africa reaches 95 cm and 40 kg, and can lay more than 100 eggs at a time, and
- Podocnemis expansa (https://www.inaturalist.org/taxa/40147-Podocnemis-expansa) of the Amazon reaches 107 cm and more than 70 kg, and lays up to 136 eggs at a time.
Thus, species extending south to the same latitudes and living in comparable habitats are 2-3-fold more massive than any testudines living in Australia.
CROCODILIA (https://en.wikipedia.org/wiki/Crocodilia)
It has long been customary to regard northern Australia as having the largest crocodiles on Earth. However, this is questionable.
Crocodylus porosus (https://www.inaturalist.org/taxa/26068-Crocodylus-porosus) is only marginally Australian, and is not necessarily more massive than Crocodylus niloticus (https://www.inaturalist.org/taxa/341972-Crocodylus-niloticus) of Africa.
Crocodylus porosus is the most marine of crocodilians, and no individual has been shown to live its full life within Australia.
The largest crocodilian at similar latitudes in South America is Melanosuchus niger (https://www.inaturalist.org/taxa/116532-Melanosuchus-niger), which not only is restricted to fresh water, but spends much of its time in the Amazon rainforests themselves. This species is shorter than its Australian counterpart, but is so heavily armoured that it may rival it in the maximum body mass of females.
Even if we accept that a few exceptional individual males of C. porosus might once have reached 7 m long in Australia, so did C. niloticus in southern Africa, which is the more massive species with a proportionately short tail.
C A W Guggisberg, in his book 'Crocodiles: their natural history, folklore and conservation' (https://catalogue.nla.gov.au/catalog/2003481), reports that a specimen shot in 1903 in Malawi, southern Africa, by Hans Besser, "an excellent field naturalist whose reliability cannot be questioned," was 7.6 m long, despite its tail having been shortened further by partial amputation.
The Guinness book of animal records (1995, https://www.amazon.com.au/Guinness-Book-Animal-Records/dp/0851126588) states: "The longest authenticated record of recent years is a male saltwater crocodile (Crocodylus porosus) just over 7 m...long, which lives in the Bhitarkanika Wildlife Sanctuary, Orissa State, India." (Note that the record individual of the Australian species, C. porosus, was not in Australia but on the Asian mainland.)
Crocodylus niloticus is less sexually dimorphic than C. porosus, suggesting that females of the Australian species (which reach only 3 m) may fall short of females of the southern African species. Researcher H B Cott (https://en.wikipedia.org/wiki/Hugh_B._Cott) recorded a female individual of C. niloticus to be 5.6 m long. This is borne out by the fact that the southern African species can lay clutches of up to 95 eggs, compared to only 72 in the case of C. porosus of Asia and Australia.
VARANIDAE (https://en.wikipedia.org/wiki/Varanidae)
Varanus giganteus (https://www.inaturalist.org/taxa/39453-Varanus-giganteus) of Australia, despite its reputation (https://www.google.com.au/search?q=Perenty+australia%27s+giant+lizard&sca_esv=571840155&sxsrf=AM9HkKmC2jnLMvgturnDMJLSkaIyWmwNQw%3A1696838772669&source=hp&ei=dLQjZfHKJZTL2roPxKmj4Ak&iflsig=AO6bgOgAAAAAZSPChPlONWx-0RIfi-8vxQ5Zvx498N47&ved=0ahUKEwjx1KGCweiBAxWUpVYBHcTUCJwQ4dUDCAw&uact=5&oq=Perenty+australia%27s+giant+lizard&gs_lp=Egdnd3Mtd2l6IiBQZXJlbnR5IGF1c3RyYWxpYSdzIGdpYW50IGxpemFyZDIFECEYoAFItWdQiwhY11ZwAXgAkAEAmAG7A6ABmz-qAQowLjMuMjMuNS4xuAEDyAEA-AEBqAIUwgIHECMY6gIYJ8ICFhAuGAMYjwEY5QIY6gIYtAIYjAPYAQHCAhYQABgDGI8BGOUCGOoCGLQCGIwD2AEBwgIHECMYigUYJ8ICBBAjGCfCAgsQABiABBixAxiDAcICCxAuGIoFGLEDGIMBwgILEC4YgwEYsQMYgATCAggQABiABBixA8ICERAuGIAEGLEDGIMBGMcBGK8BwgIOEC4YgAQYsQMYxwEY0QPCAgwQIxiKBRgnGEYYgALCAgUQLhiABMICCxAuGIAEGLEDGIMBwgILEC4YgAQYxwEYrwHCAggQLhiABBixA8ICDhAuGIAEGMcBGK8BGJgFwgIFEAAYgATCAgsQLhivARjHARiABMICDRAuGIMBGLEDGIAEGArCAgcQABiABBgKwgIcEC4YgwEYsQMYgAQYChiXBRjcBBjeBBjfBNgBAsICBxAuGIAEGArCAhYQLhiABBgKGJcFGNwEGN4EGN8E2AECwgIIEAAYFhgeGArCAgcQIRigARgKwgIHEC4YDRiABMICBhAAGBYYHsICCBAAGAgYHhgNwgIIEAAYigUYhgPCAhYQLhgNGIAEGJcFGNwEGN4EGN8E2AECwgIFEAAYogTCAggQABiJBRiiBLoGBggBEAEYC7oGBggCEAEYFA&sclient=gws-wiz#fpstate=ive&vld=cid:a3482070,vid:bsC1dzwPs2k,st:0), is less massive (up to 15 kg) than its largest congener in southern Africa, namely Varanus niloticus, which is as long but more thickset.
S Spawls and his co-authors, in their authoritative 'Field guide to the reptiles of East Africa' (2002, https://www.abebooks.com/9780126564709/Field-Guide-Reptiles-East-Africa-0126564701/plp), state that V. niloticus has been recorded to reach at least 2.5 m long in southern Africa - implying a body mass over 20 kg. This is borne out by the fact that the Australian species, V. giganteus, lays up to 11 eggs, whereas V. niloticus lays up to 60 eggs, per clutch.
The Australian species does, however, beat any South American lizard in maximum size.
The family Varanidae is absent from the Americas. Although the tegus (largest members of Teiidae) are mainly carnivorous lizards remarkably similar to varanids, they fall short in size.
The largest is Salvator rufescens (https://www.inaturalist.org/taxa/318759-Salvator-rufescens) of semi-arid thorn scrub (chaco, https://en.wikipedia.org/wiki/Gran_Chaco) in South America. With a snout-vent length exceeding 50 cm, and a total length of up to 1.3 m, S. rufescens is larger than any agamid (https://www.inaturalist.org/observations?place_id=6744&taxon_id=31096&view=species) or scincid (https://www.inaturalist.org/observations?place_id=6744&taxon_id=36982&view=species), but smaller than several species of varanid, in Australia.
The largest lizard in South America is herbivorous, but still falls short of the Australian V. giganteus: Iguana iguana (https://www.inaturalist.org/taxa/35342-Iguana-iguana) of the Amazon, which reaches up to 10 kg.
SERPENTES (https://en.wikipedia.org/wiki/Snake)
Both the venomous and the non-venomous snakes of Australia fall short of their southern African or South American counterparts in maximum size.
Even if extreme lengths attributed to Oxyuranus scutellatus (https://www.inaturalist.org/taxa/35170-Oxyuranus-scutellatus), viz. more than 3 m, are true, they do not exceed the values attributed to the longest venomous snakes elsewhere.
More importantly, the lack of Viperidae (https://www.inaturalist.org/observations?place_id=any&taxon_id=30667&view=species), which are thickset compared to Elapidae, limits the maximum body mass of venomous snakes in Australia.
The largest in Australia is probably the tropical form of Pseudechis australis (https://www.inaturalist.org/taxa/35161-Pseudechis-australis), which is thickset compared to O. scutellatus and can also exceed 2 m.
However, P. australis falls short of Bitis gabonica (https://www.inaturalist.org/taxa/30853-Bitis-gabonica) of southern Africa and Lachesis muta (https://www.inaturalist.org/taxa/73840-Lachesis-muta) of South America, both of which occur at similar latitudes. This is mainly because B. gabonica has a far greater body width (up to 17 cm, corresponding to a girth of up to 37.5 cm) than any snake in Australia.
R M Isemonger, in his book 'Snakes of Africa' (https://www.abebooks.com/signed-first-edition/Snakes-Africa-Isemonger-R.M-Books-PTY/22383738528/bd), recorded an individual of B. gabonica with length 1.75 m and body mass 8.4 kg. This species produces up to 60 offspring at a time, compared to only up to 20 for P. australis of Australia.
According to 'The Guinness book of animal facts and feats' (https://find.slv.vic.gov.au/discovery/fulldisplay/alma996223373607636/61SLV_INST:SLV), B. gabonica has probably the longest fangs (up to 5 cm), and the greatest average yield of venom, of any snake on Earth. Lachesis muta is not as thickset as B. gabonica, but is more thickset than any long venomous snake in Australia, and clearly exceeds the maximum length of P. australis (3.4 m vs 2.7 m).
This gives the South American species, L. muta, a maximum body mass of probably more than 10 kg, without peer in Australia.
Simalia kinghorni, largest snake in Australia, is so slender that it has never been recorded to exceed 26 kg, and can lay only up to 20 eggs per clutch. Research by R G Shine (https://www.publish.csiro.au/wr/wr04084 and https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/jzo.12837) has shown that large male individuals of S. kinghorni are about 50% more massive than their mates.
The southern African Python natalensis (https://www.inaturalist.org/taxa/111451-Python-natalensis), although no longer than 5.6 m, may exceed 100 kg, and it is females that are largest, laying up to 100 eggs per clutch. Furthermore, the largest prey item (59 kg) known to have been swallowed by an African python, belonging to Aepyceros melampus (https://www.inaturalist.org/taxa/42278-Aepyceros-melampus), is itself more than double the body mass of the largest snake in Australia.
Eunectes murinus (https://www.inaturalist.org/taxa/32213-Eunectes-murinus) of the Amazon, which exceeds 200 kg, is at least as long (up to 8.5 m) as the Australian S. kinghorni, and incomparably more thickset. Females of E. murinus are much more massive than males.
to be continued in https://www.inaturalist.org/journal/milewski/85595-australia-is-a-land-of-reptiles-but-not-particularly-large-ones-part-2-the-great-south-land-here-be-slight-dragons#...
Australia is a land of reptiles, but not particularly large ones, part 2: 'The Great South Land: Here Be Slight Dragons'
...continued from https://www.inaturalist.org/journal/milewski/85581-australia-is-a-land-of-reptiles-but-not-particularly-large-ones-part-1-turtles-tortoises-lizards-and-snakes#
Although Australia is continent-size, it falls short of its surrounding islands in the maximum size of living reptiles.
- The largest of all agamids, Hydrosaurus amboinensis (https://www.inaturalist.org/taxa/1120224-Hydrosaurus-amboinensis), occurs not in Australia but on the islands of eastern Indonesia (https://en.wikipedia.org/wiki/Indonesia).
- The skincid Corucia zebrata (https://www.inaturalist.org/taxa/37194-Corucia-zebrata) of the Solomon Islands (https://en.wikipedia.org/wiki/Solomon_Islands), although arboreal, is reputed to be more massive than even the largest Tiliqua (a genus of unusually thickset, terrestrial skinks) in Australia.
- Not only does Varanus komodoensis (https://www.inaturalist.org/taxa/39449-Varanus-komodoensis and https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2748693/) of Indonesian islands (https://upload.wikimedia.org/wikipedia/commons/4/4c/Komodo_dragon_distribution.gif) far outsize its Australian congeners, but the largest varanid in New Guinea (Varanus salvadorii, https://www.inaturalist.org/taxa/39440-Varanus-salvadorii) is also longer, and possibly more massive, than V. giganteus of Australia.
- The largest gekkonid on Earth is Rhacodactylus leachianus (https://www.inaturalist.org/taxa/33862-Rhacodactylus-leachianus) of New Caledonia (https://en.wikipedia.org/wiki/New_Caledonia).
- Even in the case of Pygopodidae (https://en.wikipedia.org/wiki/Pygopodidae), a family restricted to Australasia, the largest species (Lialis jicari, https://www.inaturalist.org/taxa/36977-Lialis-jicari) appears to occur in New Guinea, not Australia.
- The only rhynchocephalians (https://en.wikipedia.org/wiki/Rhynchocephalia) remaining on Earth have survived in New Zealand (Sphenodon punctatus, https://www.inaturalist.org/taxa/200834-Sphenodon-punctatus), not in Australia.
There is a general tendency for the largest animals to have males larger than females. For examples, elephants, giraffes, and kangaroos all have mature males double the body mass of mature females.
Perhaps one reason is that, at the upper limit of body sizes that a habitat can support, animals economise on the number of mature males by means of extreme polygamy and competition among males.
In the extreme sexual dimorphism of the largest crocodilians and lizards, Australia may be unremarkable. However, in the case of snakes, Australia is opposite to the other southern continents, because both P. australis and S. kinghorni have males larger than females, whereas the converse applies to vipers, rock pythons, and anacondas.
If comparisons were standardised to females, the slightness of the Australian reptiles might be even more pronounced than I have shown. For example, it remains possible that the largest female varanid in Australia is less massive than the largest female iguana in South America, which can lay up to 45 eggs per clutch.
Herbivorous reptiles are thickset, partly because greens can only be digested by means of fermentation in bulky guts. The most striking gap in the reptile fauna of Australia is its lack of herbivores, particularly land tortoises but also lizards.
Agamidae and Iguanidae are closely related, and Intellagama lesueurii (https://www.inaturalist.org/taxa/146186-Intellagama-lesueurii) of Australia may resemble juveniles of Iguana iguana. However, no agamid in Australia is herbivorous.
Thus, remarkably, the largest female individual of any kangaroo alive today (35 kg) is smaller than the largest female individual of any tortoise alive today in southern Africa and probably South America - which are likewise grazers.
The lack of herbivorous reptiles in Australia is not explained by isolation.
- As part of Gondwana, Australia and South America supported giant land tortoises (Meiolania, probably up to 500 kg, https://en.wikipedia.org/wiki/Meiolania). This group survived on Lord Howe Island (https://en.wikipedia.org/wiki/Lord_Howe_Island), just east of Australia, as recently as the Pleistocene.
- Modern tortoises have proved to be excellent colonisers of islands.
- Iguanids may also have a Gondwanan ancestor, and in any event have reached remote islands such as the Galapagos (https://en.wikipedia.org/wiki/Gal%C3%A1pagos_Islands), Madagascar (https://en.wikipedia.org/wiki/Madagascar), and Fiji (https://en.wikipedia.org/wiki/Fiji).
ECOLOGICAL EXPLANATION
An important factor may be fire.
All vegetation types in Australia burn, other than a few small pockets of 'rainforest' (https://www.dcceew.gov.au/sites/default/files/documents/mvg1-nvis-rainforests-and-vine-thickets.pdf). By contrast, part of southern Africa and much of South America are free of wildfires.
It is obvious that crocodiles, freshwater turtles, and anacondas are safe from flames. However, scorching is one of the greatest threats to tortoises massive enough to thwart large predators.
Stigmochelys pardalis (https://en.wikipedia.org/wiki/Leopard_tortoise) is commonest and largest-bodied in vegetation such as that dominated by a giant purslane (Portulacaria afra, https://www.inaturalist.org/taxa/326086-Portulacaria-afra) in the Eastern Cape of South Africa. This succulent thicket occurs under a semi-arid climate at the latitude of southern New South Wales (https://en.wikipedia.org/wiki/New_South_Wales), but differs radically from mallee (https://www.anbg.gov.au/photo/vegetation/mallee-woodlands-shrublands.html and https://en.wikipedia.org/wiki/Mallee_(habit)) in being fire-proof.
The largest non-venomous snakes on all three southern continents are restricted to fire-free vegetation. However, a difference remains in the availability of prey such as the fast-growing hares (https://www.inaturalist.org/observations?place_id=113055&taxon_id=43094&view=species), pigs (https://www.inaturalist.org/observations?place_id=113055&taxon_id=42118&view=species), and antelopes (https://www.inaturalist.org/observations?place_id=113055&taxon_id=42241&view=species) of Africa.
Eunectes murinus (https://en.wikipedia.org/wiki/Green_anaconda) also eats prey with no counterparts in Australia, such as giant rodents (https://en.wikipedia.org/wiki/Capybara), and depends on floating meadows that are far more extensive than any similar vegetation on Australian floodplains.
Where does this leave the extinct giant varanid, Megalania prisca (https://prehistoric-fauna.com/Varanus-priscus)?
In a book devoted to this species, 'Dragons in the dust' (https://catalogue.nla.gov.au/catalog/3095349), R E Molnar explains that only a few bones of this species have ever been found, so that its full skeleton can be reconstructed only by guesswork. Past attempts to do so have - perhaps falsely - used the extant Varanus komodoensis as a model.
I have no reason to doubt that mature males may have reached 6 m. However, estimated body masses are another matter. If the extinct giant varanid was slender, in line with other Australian reptiles, its body mass might not have exceeded 250 kg - perhaps inferior to the largest extinct species of Varanus from the fossil beds of the Siwalik Hills (https://en.wikipedia.org/wiki/Sivalik_Hills) in mainland Asia.
Please bear in mind the surviving members of the same family:
.Varanus komodoensis and the largest congener at similar latitudes in New Guinea, to the east, both reach 3 m long, but differ perhaps 6-fold in maximum body mass.
Bulk counts, which is why Varanus salvadorii - although it may turn out to be the longest lizard alive on Earth today (https://www.researchgate.net/figure/Varanus-salvadorii-is-the-largest-monitor-lizard-of-New-Guinea-and-the-only_fig13_236013907) - has yet to gain a reputation as a dragon.
2023年10月12日
A comparison of fecal pellets between the moose (Alces alces) and the common eland (Taurotragus oryx)
@muir @kevinatbrakputs @beartracker @paradoxornithidae @photogenie
The feces of the moose (Alces alces) and its namesake the common eland (Taurotragus oryx) are so similar that they seem indistinguishable, at a macroscopic level.
This similarity applies to
- a seasonal difference, in which the feces are distinctly pelletised only at times when succulent green food is unavailable,
- size and shape of the pellets, and the variation in both, and
- the texture of the contents of the pellets, which is relatively coarse for ruminants (e.g. compare Bos taurus and Giraffa giraffa).
The number of photos of feces on the Web are several orders of magnitude greater for the moose than for the common eland. However, there are just enough photos for the latter species to allow the comparison below.
ALCES ALCES
https://www.inaturalist.org/observations/183568029
https://www.inaturalist.org/observations/187205878
https://www.inaturalist.org/observations/186764594
https://www.inaturalist.org/observations/186455292
https://www.inaturalist.org/observations/185673679
https://www.inaturalist.org/observations/183822178
https://www.inaturalist.org/observations/185524086
https://www.inaturalist.org/observations/183639684
https://www.inaturalist.org/observations/183271551
https://www.inaturalist.org/observations/182518957
https://www.inaturalist.org/observations/181301581
https://www.inaturalist.org/observations/181000203
TAUROTRAGUS ORYX
https://www.inaturalist.org/observations/106423609
https://www.inaturalist.org/observations/115207648
https://www.inaturalist.org/observations/113743011
https://www.inaturalist.org/observations/77094002
https://www.inaturalist.org/observations/61026612
https://www.inaturalist.org/observations/44146771
https://www.inaturalist.org/observations/98480195
https://www.inaturalist.org/observations/44116265
https://www.inaturalist.org/observations/70331422
https://www.inaturalist.org/observations/103712571
https://www.inaturalist.org/observations/29268023
https://www.inaturalist.org/observations/23928468
2023年10月13日
Body sizes and diets in the herbivorous guild in Trans-Himalaya
TRANS-HIMALAYA https://en.wikipedia.org/wiki/Transhimalaya
SPITI VALLEY https://en.wikipedia.org/wiki/Spiti
Lepus oiostolus 3 kg 36 grass
https://www.inaturalist.org/taxa/43124-Lepus-oiostolus
Marmota himalayana 6 kg
https://www.inaturalist.org/taxa/46094-Marmota-himalayana
Procapra picticaudata 14 kg 3-16% grass
https://www.inaturalist.org/taxa/42372-Procapra-picticaudata
Pantholops hodgsonii 32 kg 32-71 % grass
https://www.inaturalist.org/taxa/42382-Pantholops-hodgsonii
Pseudois nayaur 55 kg mainly grass
https://www.inaturalist.org/taxa/42313-Pseudois-nayaur
https://www.alamy.com/stock-photo-india-jammu-kashmir-ladakh-gata-loops-flock-of-wild-ibex-88956100.html?imageid=857EBC32-C2B9-4BD0-831B-D982A0B40DED&p=65641&pn=1&searchId=78f028135ba3c478783fd154ae2d36fb&searchtype=0
Capra sibirica sakeen 76 kg mainly grass
https://www.inaturalist.org/taxa/42351-Capra-sibirica
https://www.autentic.com/67/pid/1392/The-Himalayan-Ibex-Monarchs-of-the-Mountains.htm
https://www.natureinstock.com/search/preview/himalayan-ibex-capra-sibirica-hemalayanus-male-they-live-at-elevations-of/0_12570777.html
https://www.naturepl.com/stock-photo-nature-image01612182.html
https://www.inaturalist.org/observations/167171059
https://www.flickr.com/photos/125836731@N08/33477449935
https://www.inaturalist.org/observations/186435121
Capra hircus females 33 kg males 35 kg
https://www.inaturalist.org/taxa/123070-Capra-hircus
Ovis ammon 87 kg 24-88% grass
https://www.inaturalist.org/taxa/42392-Ovis-ammon
Ovis aries females 34 kg males 35 kg
https://www.inaturalist.org/taxa/121578-Ovis-aries
Equus kiang 275 kg 84-100% grass
https://www.inaturalist.org/taxa/43338-Equus-kiang
Equus asinus females 97 kg males 83 kg
https://www.inaturalist.org/taxa/148030-Equus-asinus
Equus caballus females 248 kg
https://www.inaturalist.org/taxa/209233-Equus-caballus
Bos mutus 413 kg 44-96% grass
https://www.inaturalist.org/taxa/890122-Bos-mutus
Bos grunniens females 228 kg males 368 kg
https://www.inaturalist.org/taxa/889089-Bos-grunniens
Bos taurus females 191 kg
https://www.inaturalist.org/taxa/74113-Bos-taurus
Variation in walking gaits in ungulates, part 2: the moose walks like the pygmy hippo, while warthogs walk like giraffes
@paradoxornithidae @matthewinabinett @beartracker @tandala @oviscanadensis_connerties @elliotgreiner @dejong @muir @maxallen @aguilita @jwidness @ptexis @christiaan_viljoen
...continued from https://www.inaturalist.org/journal/milewski/85161-variation-in-walking-gaits-in-ungulates-why-some-hoofed-mammals-cross-walk-whereas-others-amble-part-1#
Two salient findings emerge from part 1 of this Post. Neither has, as far as I know, been pointed out in the previous literature on gaits (https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2907.1973.tb00179.x and https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.1968.tb03031.x and https://uwspace.uwaterloo.ca/handle/10012/14529).
The surprises are as follows:
Firstly, the moose (Alces alces, https://www.inaturalist.org/taxa/522193-Alces-alces) and the pygmy hippo (Hexaprotodon liberiensis, https://www.inaturalist.org/taxa/74192-Choeropsis-liberiensis) share the same walking gait, despite their great differences in body shape, particularly the proportional lengths of the legs.
In both cases, the gait is a semi cross-walk.
Secondly, the common warthog (Phacochoerus africanus, https://www.inaturalist.org/taxa/42122-Phacochoerus-africanus) and giraffes (Giraffa) share the same walking gait, despite their great differences in body size and shape, particularly the proportional lengths of the legs (https://dissolve.com/video/Locked-off-shot-two-warthog-eating-rights-managed-stock-video-footage/002-D118-68-503 and https://www.theatlantic.com/personal/archive/2013/04/friday-fauna-3-tall-giraffes-and-1-short-warthog/274723/ and https://www.travelblog.org/Photos/2106756 and https://www.istockphoto.com/photo/giraffe-oryx-warthog-species-diversity-at-a-waterhole-in-the-etosha-national-park-gm647776896-117801181).
In both cases, the gait is an amble.
The following illustrates the difference between the semi cross-walk of the common eland and the amble of giraffes.
Please focus on the limbs on the far side of the figure.
In the common eland (https://www.inaturalist.org/observations/182080028), the fore hoof lifts only when the hind hoof is placed right behind it.
By contrast, in giraffes (https://unsplash.com/photos/4NxLCYwza6g and https://classroomclipart.com/image/photo/reticulated-giraffes-walking-in-grasslands-kenya-picture-38-42926.htm), the fore hoof has already lifted by the time that the hind hoof approaches it.
This difference is not just the result of giraffes having long legs. Warthogs (https://www.alamy.com/southern-warthog-phacochoerus-africanus-sundevallii-side-view-of-an-adult-walking-on-the-ground-mpumalanga-south-africa-image354035050.html?imageid=02D8ECD0-F02C-4C14-BB66-E8696810999C&p=240867&pn=1&searchId=50bc9da712002d08dc43c752e0d32504&searchtype=0) have legs proportionately shorter than those of the common eland, yet the fore hoof has already lifted by the time that the hind hoof approaches it.
The fact that warthogs - the shortest-legged of the 'plains game' of Africa - walk like giraffes has never, as far as I know, been pointed out before.
https://www.shutterstock.com/image-photo/giraffe-warthog-drinking-together-waterhole-1184950966
These findings are noteworthy, because
- it is easy to assume that the amble of giraffes is a function of their long legs (https://academic.oup.com/jmammal/article-abstract/41/2/282/933378?login=false),
- the moose is by far the longest-legged of deer, and
- all other suids, plus peccaries (https://www.shutterstock.com/image-photo/javelina-aka-wild-skunk-pig-peccary-1171187206 and scroll to 9th photo in https://a-z-animals.com/animals/collared-peccary/pictures/ and https://www.freeimages.com/photo/javelina-walking-1337436), cross-walk.
An additional surprise is that Okapia differs from Giraffa in its walking gait - a point missed by Anne Innis Dagg despite her close scrutiny of both genera. Please see comment below, titled OKAPIA JOHNSTONI.
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