High Living; above the treeline: #1

This is another in an irregular (and hitherto informal) series on habitats. Earlier ones were on intercontinental habitats mangroves and sandstone, and a uniquely Australian one, the mallee. I have ideas for future ones on rainforests (probably with separate offerings on tropical and temperate rainforests and cloud forests), deserts, woodlands, grasslands and wetlands, but any other suggestions welcomed!

Today however I'm starting at the top, as it were. 'Alpine' is a term used often just to refer to mountains (originally specifically referring to European mountain ranges, though the etymology, from Latin, is unclear), but ecologically it has a more precise definition. It is that area above the treeline, where conditions are too harsh - specifically with insufficient solar energy - to support trees. It is defined around the world as the elevation at which the mean temperature of the warmest month is below 10 degrees Celsius. Below that there is simply not enough available solar energy to build and maintain the massive trunks and supporting root systems that define a tree. The line is often quite abrupt, though locally the altitude will vary locally depending on the landscape; trees might grow higher in sheltered situations on sunny slopes. And of course it is lower towards the poles and higher in the tropics, so some of what follows on the treeless zones in the far south of South America does not necessarily relate to high mountains. 

Treeline at 1800 metres above sea level (masl from here on) in the Australian alps
in Kosciuszko NP, far southern NSW, at 36.5 degrees south.

Across the Pacific and much further south at 52 degrees of latitude, the treeline at
Puerto Natales in Chilean Patagonia is at only 1200masl. 

However nearby in Torres del Paine National Park, the influence of constant winds from the huge Southern Patagonian Ice Field, the second largest ice field in the world* outside the polar regions, brings the tree line down to 500masl. (*The only larger one is in south-eastern Alaska.) The vast grassy and heathy plains there are part of the Patagonian Steppe, most of which is found in Argentina.

The spectacular Torres del Paine skyline from the south.

These lakes at Torres del Paine are less than 100masl; the forest doesn't extend far above
them on the Horns. 

This spectacular range however is not in the Andes chain. It is instructive (and equally, I hope, attractive!) to look at some Andean mountains up the chain from Tierra Del Fuego to northern Ecuador, almost on the equator, noting how the treeline rises as we go north.

Here near Ushaia in Argentinian Tierra del Fuego at 55 degrees south, the world's longest 
(and second highest) mountain range ends - or rather rather disappears under the ocean 
to reappear briefly as Cape Horn. The treeline here is at 500-600masl.

Volcano Calbuco, in the Lake District of northern Chilean Patagonia at 41 degrees south
 (a little further north than Hobart). Here the trees end at approximately 1300masl.

Nearby, above Lago Llanquihue ('yahn-KEE-way') is the perfect volcanic dome of Orsono.

This is not a particularly high mountain by Andean standards at 2600masl, and 
as we'd expect from the situation on Calbuco, the trees only go about halfway up.

Then we go much further north, deep into the tropics in Ecuador (I'll show some landscapes in between soon, but they mostly don't involve specific mountains). 

Volcano Chimborazo, in the centre of the Ecuadorian Andes, a truly mighty mountain and
the highest in Ecuador. It's snowy peaks are 6300masl, and the clearly delineated treeline is
 here at 3500masl (much higher than the highest point in Australia, on top of Mt Kosciuszko),
as it is for the next two Ecuadorian volcanoes, not much further north.

Volcano Cotopaxi, a 5900m active volcano clearly visible from Quito; this however was
taken from Papallacta Pass about 80km away, while heading east over the Andes to the Amazon basin.

Sunrise on Volcano Antisana, 5800masl, from the deck of the lovely Wild Sumaco Lodge
on the eastern slope of the Andes, 70km away. It is only 50km from the equator.

And before we take a much closer look at the ground on some very high mountain ranges, here are three more tropical mountains that I feel privileged to have seen as well, on a couple of other continents. 

The spectacular mass of Mount Kinabalu in Sabah, Malaysian Borneo, 6.5 degrees 
north of the equator. It's peak is at 4100masl and the clear treeline is 3400masl.

Mount Kenya (for which the country was named, incidentally) is less than 20k south
of the equator, which actually runs across its lower slopes. A fraction of the original
glaciers can just be seen in this somewhat murky photo; the Kenyan Wildlife Service
predicts that they will disappear by about 2050. The treeline is at 3500m and 
with a high point of 5200masl, only one African mountain is taller...

Young Cheetahs playing in front of magnificent Mount Kilimanjaro, in fading light
in northern Tanzania (taken from Amboseli NP, to the north across the border in Kenya). 
It is 3 degrees south of the equator, rises to 5900masl (4900 metres above the plains)
and the treeline is at 3800 metres - two vertical kilometres above Kosciuszko's
highest Snow Gums!

Treelines themselves are interesting, as a transition zone from forest or subalpine woodland to treeless heathland or grassland (or a mix of the two). Generally up here the trees are sparser and more stunted as they struggle at their ecological limits. The understorey here includes species that are shared with the true alpine zone above it, though up there are also plants which specialise in the harsh treeless zone. 

Elfin forest at Acjanaco Pass at about 3800masl on the Manu Road from Cusco to
the Amazon basin in the southern Peruvian Andes.

At the upper edge of the elfin forest we can just see the start of the high altitude 
treeless grasslands of the Puna in the mist.

Within the elfin forest though is a wealth of flowering plants, especially orchids, and birdlife. 

Epidendrum ardens, endemic to the Peruvian cloud forests.

Odontoglosssum (or Cyrtochilum) mystacinum, another cloud forest specialist,
also found in Ecuador and Bolivia. 

In some places bamboos form part of the highest forests.

Bamboo Chusquea sp. just below the treeline at 3400masl in the Talamanca Range
in central Costa Rica.

In El Cajas National Park near Cuenca in southern Ecuador there is an interesting situation. The treeline in general is around 3300masl as we'd expect in the tropics, but there is an exception. The remarkable Queñoa trees Polylepis spp. (family Rosaceae) can form thickets far above the treeline, to over 4000masl, at the highest elevation of any tree in the world. 

Polylepis thicket high in El Cajas NP.

Polylepis growing above the otherwise treeless boggy páramo in El Cajas NP.

In Australia the trees that form the treeline are Snow Gums - Eucalyptus pauciflora on the mainland and E. coccifera in Tasmania. Beneath them are plants which continue upwards to grow on the harsh treeless alpine heaths.

Old gnarled Snow Gums at 1770masl at Charlottes Pass, Kosciuszko NP, 
only just below the treeline.

Daisies growing among the Snow Gums at about 1700masl on Mount Ginini
in the Brindabella Ranges above Canberra. This is below the Kosciuszko treeline,
but in addition this is a bit north of Kosciuszko so we'd expect the treeline to be a bit higher.
There is very little true alpine habitat in the ACT.

Pineapple Grass Astelia alpina (actually a lily, family Asteliaceae) growing
under Tasmanian Snow Gums at Mount Field NP, Tasmania. It is a common
plant in alpine bogs in Tasmania. The treeline here is at 1200masl, which
matches that of mountains at the same latitude in Patagonia.

So what does it look like above the snowline where the trees can't survive? I can only offer photos from South and Central America and Australia - I've not been that high in either Borneo or Africa. (I was planning to include Ireland but have realised that the landscape has been so cleared of trees over the last couple of millennia that the original treeline does not exist.) 

Mat plants and 'cushions' - opposites to a tree - reduce wind resistance and enable shoots to be protected inside the foliage. 

Hard cushions of Azorella sp., Family Apiaceae, are prominent in the landscape around
Chivay and the Colca Canyon, at over 3600masl in the southern Peruvian Andes.

In the Australian Alps (and elsewhere in the world) many unrelated species form dense mats across
the ground and rocks. This is Snow Beard-heath Leucopogon montanus. 
Most other Leucopogons I know grow as shrubs.

In the central-southern Andes of southern Peru, Bolivia and Patagonia (ie Chile and Argentina) the puna comprises vast areas of dry grasslands.

Puna as far as we can see, at 4000masl in the Andes above Cusco, southern Peru.

Puna below the Horns, Torres del Paine NP, Chilean Patagonia.

Further north (from northern Peru), the páramo is boggier and with a more heathy/shrubby vegetation.

The view from 4200masl of El Cajas NP, páramo and ponds.

Páramo at 3400masl in the central highlands of Costa Rica, dominated by low shrubs.

Eventually there are altitudes where very little grows at all. I'm no mountaineer; the highest I've been on the ground is 4900masl (by vehicle!) at Patapampa Pass in southern Peru, where the landscape is as barren as anything I've seen, beyond which is a magnificent vista of volcanoes on the horizon. I am fortunate in not being particularly susceptible to altitude sickness, but the short walk from the vehicle to the little lookout was a bit of a struggle! Needless to say, the local women selling crafts by the roadside were entirely unfazed by it.  

This is far from the upper limits of plant growth, which is over 6000masl in 
the Himalayas, and I think that this is literally a scorched landscape 
from past eruptions by the nearby volcanoes.

Volcanoes Ampato, Sabancaya and Hualca Hualca, between 10 and 20km away from
Patapampa Pass. Sabancaya is very much an active volcano and erupts constantly
(part of the cloud just above it is actually smoke), but I don't know when lava last flowed this far.

And finally some Australian alpine landscapes, which provide less than 0.1% of the continent's landmass; it is a very old and eroded continent and the mean altitude is only 300masl. 

Looking east from near the summit of Mount Kosciuszko, the highest point of Australia (not
including the sub-Antarctic territories) at a mere 2228masl.

Looking across the granite landscape to Lake Cootapatamba, the highest lake in Australia.
It is a cirque lake, gouged out by glaciers in the most recent glaciation, 
some 15,000 to 20,000 years ago.

The brief summer flowering is spectacular; here is a field of snow daisies Celmisia sp. on the
Main Range of Kosciuszko NP.

Along with the adjoining Victorian Alps, the only other Australian alpine areas of significance are in Tasmania to the south, where its higher latitude compensates for the lower altitudes.

Granites and heath on kunanyi / Mount Wellington above Hobart.

Cloud, granite and heath on Ben Lomond NP, a spectacular mountain plateau
in north-eastern Tasmania.

Wombat Moor on Mount Field, west of Hobart.

And that might be enough of mountains for one sitting. Next time I'll conclude this blog with a post on some high altitude plants; I'd been planning to do a joint post on plants and animals, but it would have been a long one, perhaps testing your patience unreasonably. So two posts still to come on this topic. Thanks for staying with me, despite the cold and the thin air.

NEXT POSTING THURSDAY 23 JULY

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Birds and Flowers

As we in the south of the world head into the colder time of the year, the north is welcoming spring. In Australia we are still firmly (and quite properly) restricted in our activities, though mostly not entirely confined to home. None of us can safely enjoy nature to the extent we're used to, but for most of us there's always something. My small contribution is to offer little windows onto various aspects of the natural world and at the moment something that might bring a smile seems called for. Birds and flowers both meet that requirement - in combination I reckon there's a lot of happy distraction.

Rainbow Lorikeet Trichoglossus moluccanus on Coral Tree flower (Erythrina sp.),
near Nowra, southern New South Wales.
[The big blazing pea flowers of this South American tree are a feature of the landscape
round that part of the world (where they are often mistaken for the unrelated
Illawarra Flame Tree Brachychiton acerifolius); they are all hybrids, apparently deriving from
plants growing in New Zealand. Anyway, that's a digression!]

Many parrots chew on flowers, but most of them do so destructively, taking the nectar for energy and the pollen for protein; some may incidentally transfer pollen to other flowers but they're unlikely to be offering much of a service to the plants.

Austral Parakeet Enicognathus ferrugineus feeding on Notro Embothrium coccineumat the Cuevo de Milodon* near Puerto Natales, southern Chile. This is the world's southern-most
parrot, and the beautiful Notro (very like the Australian waratahs and closely related to them)
is widespread in Patagonia.
(*Go to 10th photo in link.)

Crimson Rosella Platycercus elegans feeding on Banksia marginata, Australian National University.
As you can see there is nothing delicate about this feeding - the lovely bird is just ripping flowers from the spike.

Mitred Parakeets Psittacara mitratus below Macchu Pichu, Peru.
This seems to be a pea flower, perhaps another Erythrina; unlike the lorikeet above they are dimembering the flowers.

Parrots aren't the only birds that take advantage of good nectar sources without transferring pollen. A group of South American tanagers bears the name flowerpiercer, which says it all! With a sharp, often curve-tipped bill, they stab the base of the flower and 'steal' the nectar without encountering the pollen.

Black-throated Flowerpiercer Diglossa brunneiventris, Chivay,
northern Peruvian Andes. This one was caught in the act of stabbing the flower base.

Glossy Flowerpiercer Diglossa lafresnayii, Yanacocha NP near Quito, Ecuador,
showing its highly specialised piercing bill.

However at some stage the lorikeets began to feed more precisely, pushing past pollen-bearing anthers to get to the nectar and in the process collecting large quantities of pollen on the face feathers and roughened tongue. Or rather, the plants began 'employing' them rather than insects, investing in copious nectar to make the parrots actively seek out the flowers; in return the plant got a larger pollinator which could take far more pollen away, and carry it much further. 

Studies on captive lorikeets showed that Yellow Gum (or Blue Gum depending on where you are) Eucalyptus leucoxylon has flowers in which the pollen is ripe before the flowers can receive pollen, to avoid self-fertilisation. Moreover the filaments which hold the pollen anthers bend over into a dense dome which effectively excludes insects. A single visit by a Rainbow Lorikeet could remove over 2000 pollen grains; when they visited older flowers ready to accept pollen they delivered on average over 120 grains per female stigma. Another strategy adopted by some - perhaps most - bird-focussed flowers is to offer nectar that is both abundant and dilute, so of limited interest to insects.

Musk Lorikeet Glossopsitta concinna, Coles Bay, Tasmania.
This little flock was feeding on a Western Australian street tree,
Red-flowering Gum Corymbia (Eucalyptus) ficifolia.
Red flowers attract birds, while not being very conspicuous to insects, which see best at the other end of the spectrum
(blues to yellows). Remember the Coral Tree flowers too.

Red-collared Lorikeet Trichoglossus rubritorquis in Darwin,
feeding on Umbrella Tree Schefflera actinophylla, a native of northern Australia.

Scaly-breasted Lorikeet Trichoglossus chlorolepidotus, Goondiwindi Botanic Gardens, south Queensland.
Birds are not restricted to red flowers, though they do seek them out.

Varied Lorikeet Psitteuteles versicolor on paperbark melaleuca, Kakadu National Park, Northern Territory.

Nectar specialising is basic to lorikeets; we have just seen evidence of it in three different genera.

Moreover, quite independently a few other parrot groups have become nectar specialists and thus pollinators as well. One of these comprises only the Australian Swift Parrot Lathamus discolor which migrates from its breeding grounds in the Blue Gum forests (E. globulus for this Blue Gum) of Tasmania to the box woodlands of south-eastern Australia.

Swift Parrot on Mount Majura, Canberra. This lovely little parrot is tragically now listed nationally
as Critically Endangered, due to habitat loss in both Tasmania and the mainland, and
unexpected nest depredations by Sugar Gliders introduced from the mainland.

A study showed that the Blue Gums depend heavily on Swift Parrots for pollination. Just one visit to a flower by a Swift Parrot leads on average to more than 75% of the seed set possible for that flower. Single visits by native insect pollinators led to no seed set, and by introduced bees no more than 7%.

Other parrots which are regarded as nectar specialists are the little hanging parrots Loriculus spp. of southern Asia, and the Neotropical genus Brotogeris. 

Plain Parakeet B. tirica in the Atlantic forests near Sao Paulo, Brazil.

Among other birds, three families are regarded as the key nectar specialisers; the Australian honeyeaters, the Neotropical hummingbirds and the African and Asian (and Australian, just) sunbirds. Unsurprisingly all have evolved relatively long slender decurved bills for probing tubular flowers - such flowers exclude most insect pollinators (though not some moths with extravagantly long proboscises). Pollen is carried mostly on forehead feathers - see the dusting on these two birds.

Eastern Spinebill male Acanthorhynchus tenuirostris Australian National Botanic Gardens.
This is the most specialised of Australian honeyeaters, with the longest bill relative to its size.
Hence we'll come back to it shortly.

New Holland Honeyeater Phylidonyris novaehollandiae with Calothamnus sp., Cape le Grande NP,
Western Australia. This is a common and widespread species in heathlands of southern Australia.

Nectar is almost pure sugar, so such specialists must also find another source of protein; pollen provides some, but most prey on insects to supplement their diet. Perhaps also unsurprisingly, but interestingly, there are examples in all three groups where some species have secondarily re-evolved shorter beaks to focus more heavily on insects again.

Allow me to introduce some members of these groups, each of which I am very fond of, though of course I know the honeyeaters best. Like the lorikeets, honeyeaters take up the nectar by capillary action with a rapidly moving tongue.

Banded Honeyeater Cissomela pectoralis; both this and the next bird were feeding in flowering
eucalypts in Nitmiluk (formerly Katherine Gorge) NP, Northern Territory.

Bar-breasted Honeyeater Ramsayornis fasciatus.

The Umbrella Tree flowers that attracted the Red-collared Lorikeet above, also brought in a range of honeyeaters - we watched it all while eating lunch on the verandah of the excellent Darwin Museum, looking out to the Timor Sea. (Though to be honest I was mostly looking upwards.)

Brown Honeyeater Lichmera indistincta, a widespread small honeyeater across most of Australia
except the south-east.

Helmeted Friarbird Philemon buceroides and White-gaped Honeyeater Stomiopera unicolor,
both restricted to the north, and both obviously bigger than the Brown, above.
The friarbirds form a small group of large honeyeaters.

And feeding on the same paperbark as the Varied Lorikeet (above) in Kakadu - and indeed with it - was another friarbird, the Silver-crowned Friarbird Philemon argenticeps.

Another group of large honeyeaters comprises the wattlebirds - named for the red fleshy wattles on the face of the first species encountered, the Red Wattlebird Anthochaera carunculata (some subsequent species inconveniently lacked this feature).

Red Wattlebird on grevillea, Australian National Botanic Gardens.
They don't normally feed on the ground, but will adapt as required.

Little Wattlebird Anthochaera chrysoptera on Banksia marginata, Lower Glenelg NP, Victoria.
The non-wattled wattlebird is common in near-coastal south-eastern Australia.

Western Wattlebird A. lunulata on Banksia speciosa, Esperance, Western Australia.
This one was long lumped with the previous one.

Dusky Honeyeater Myzomela obscura (or Dusky Myzomela, though this use of the genus name is pretty much
unknown in Australia) on a grevillea cultivar in a Darwin garden.

Eastern Spinebill male (above) and females (below),
respectively on a Grevillea sp. (or perhaps Hakea sp.) in a garden near Kyogle in northern NSW,
and an Eremophila sp. in the Australian National Botanic Gardens.

Grey-headed Honeyeater on Grevillea wickhamii, Watarrka NP, central Australia.

Scarlet Honeyeater Myzomela sanguinolenta on bottlebrush, Callistemon sp., Cape Hillsborough NP, Queensland.
A delightful little bird which deserves a better photo than this.

Yellow-faced Honeyeater Caligavis chrysops on another bottlebrush, this one in our Canberra back yard.

And for the record here's a member of one group of honeyeaters - the miners, though they're not the only ones - with short stout beaks to reflect a primarily insect diet.

Bell Miner Manorina melanophrys, Melbourne.

By now you're probably honeyeatered out, so time for some sunbirds; I find these little gems very hard to photograph - they never seem to stay still - so there might be a couple of pics here that I'd not normally impose on you, mostly for the sake of featuring at least one Asian one.

Olive-backed Sunbird Cinnyris jugularis female (above) and pair (below) getting deep into garden flowers
in Cairns, north Queensland. This is Australia's only sunbird, presumably relatively recently arrived,
being found as far north as China.

 

Eastern Double-collared Sunbird Cinnyris mediocris, Lake Nakuru, Kenya.
This was in a garden, feeding on South American fuchsias. Moreover I'm reliably assured
that this is Fuchsia magellanica from the icy depths of Patagonia; tough plants!
They of course evolved to a partnership with hummingbirds.
And I have to say that this is a most uncomfortable-looking pose.

Beautiful Sunbird Cinnyris pulchella, Serengeti NP, Tanzania.
An especially tiny sunbird, and spectacular.

Immature male Scarlet-chested Sunbird Chalcomitra senegalensis, Serengeti NP, Tanzania.
The mature male is black with a green forehead.

Temminck's Sunbird Aethopyga temminckii, Mount Kinabalu, Sabah, Malaysian Borneo.

And there is at least one equivalent to the short-billed insectivorous honeyeaters among the sunbirds too.

Ruby-cheeked Sunbird Chalcoparia singalensis, Ai Batang NP, Sarawak, Malaysian Borneo.

Which brings us to our final major nectar-slurping group of birds, the hummingbirds, a huge family mostly from tropical South and Central America. They are stunners, so without further ado here are a few with, of course, flowers. If there are too many you can of course just skip through, but I do hope you've got enough time not to do that! Their hovering abilities are of course legendary.

Eastern Mountaineer Oreonympha nobilis at wild tobacco flowers, Nicotiana sp., Huaycarpay,
southern Peruvian Andes. It is found only in a couple of valleys near Cusco.

Blue-mantled Thornbill Chalcostigma stanleyi, El Cajas NP, southern Ecuador,
at over 4000 metres above sea level.

Blue-tailed Emerald Chlorostilbon mellisugus in the rain at Aguas Verdes private reserve, northern Peru.
(More on this wonderful place here.) As you will see again below, lodges and gardens often
plant these verbenas to attract hummers.

Sapphire-vented Puffleg Eriocnemis luciani at Passiflora flowers,
El Cajas NP (see above).

Green Violetear Colibri thalassinus on wild tobacco, Sacred Valley near Cusco, southern Peru.
(Its taxonomy is a bit fluid at the moment, but this will suffice our needs.)

Oasis Hummingbird female Rhodopis vesper Azapa, northern Chile, a hummer of the desert coastline.

Rufous-crested Coquette female Lophornis delattrei, Aguas Verdes (see above).

Wire-crested Thorntail, male above, and female below, Aguas Verdes again.
This is one of my favourite hummingbirds.

 

And my final hummingbird is included (without a flower) because it is atypically 'naughty' in not probing the flower as intended, but takes a short cut to the nectar by punching a hole through the flower's base - like the flowerpiercers above.

Geoffroys's Wedge-billed Hummingbird Schistes geoffroyi, Mindo Valley, northern Ecuador.
Note the short sharp bill.

And finally (no, really!) just a couple of more minor examples of other families which partake of nectar - one does so pretty much exclusively but only contains two species, the other has many species but nectar is only taken as a part of some of their diets.

Silvereyes  Zosterops lateralis (here on a grevillea in the Australian National Botanic Gardens)
certainly pollinate flowers, but not as a major part of their life.

Cape Sugarbird Promerops cafer on a heathy plateau north of Cape Town.
One of only two species in its family, it relies heavily on protea flowers.

OK, I really hope you're not fed up with birds and flowers after this post, which became something of an odyssey! Hopefully I was able to entertain and perhaps inform you a little, both of which should be of some help in these strange, challenging times.

NEXT POSTING THURSDAY 30 APRIL.
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