Monday, 26 September 2016

Temperate Rainforests

What comes to mind when someone says the word 'rainforest'? No points for saying 'rain'. Most people would imagine a steamy, tropical envioroment, lush and green, with palms and ferns growing everywhere, and monkeys and parrots frolicking in the canopy. This is the typical image of a rainforest, and it is one that I shared with most of the public up until a few years ago. Most people think that rainforests are restricted to tropical envioroments, making the words rainforest and jungle pretty much synonymous. This is actually a false image, and when you think about it, it makes sense. The definition of a rainforest is simply an area of woodland in which the annual rain level is between 250 and 450 centimetres - notice the exception of the word 'tropical'. It only makes sense that there would be 2 variations of rainforest: the tropical type, which we are used to, and the temperate type. And indeed, this is true, although many people don't realise it. The temperate rainforest habitat is just as fascinating as its tropical counterpart, but for a few years, my knowledge of it was pitiful in amount. Recently, a personal project on creating a speculative ecosystem lead me to do some more research on the habitat, and I was so fascinated by what I found, that temperate rainforest has immediately been promoted to high up on the list of my favourite habitats. I have decided to write a blog post about what I found out.

Perhaps one of the reasons that temperate rainforests are so little known is that they are not very common.

By Koppen_World_Map_Hi-Res.png: Peel, M. C., Finlayson, B. L., and McMahon, T. A.(University of Melbourne)derivative work: Me ne frego (talk) - Koppen_World_Map_Hi-Res.png, CC BY-SA 3.0,

The above is a map of the distribution of tropical rainforests. As you can see, the habitat is in large chunks in South and Central America, Africa, Madagascar, and in the south-west Asian islands.
 Now compare that to this:

 By KarlUdo - Own work, CC BY 3.0,
The above is the distribution of temperate rainforests. While they can be found in a variety of countries, they are in much smaller areas than in their tropical counterparts.

 Perhaps the most well-known definition of a temperate rainforest is by Alaback:

"Annual precipitation over 140 cm (55 in)
Mean annual temperature is between 4 and 12 °C (39 and 54 °F)."

However, this applies only to North American temperate rainforests.
In short, the habitat in general is anywhere where a forest recieves large amounts of rainfall, creating a typically damp habitat.

By Wsiegmund - Self-published work by Wsiegmund, CC BY 2.5,

An image taken in the Pacific temperate rainforest ecoregion, in North America. It is the largest temperate rainforest ecoregion in the world.
This location is of special interest for being a standout example of the habitat. In certain areas, the biomass is at least 4 times that of any similar area in tropical regions.

The Pacific temperate rainforests are mostly coniferous, but they do sometimes have an understory of deciduous shrubs and trees. It rains a lot during the winter, but not so much during the summer - however, during the latter season, fog creeps through the forest, letting water droplets collect on surfaces, which then drip to the ground, keeping the envioroment moist. The habitat is mostly coastal, which leads to an interesting combination of both marine and forest species - for example, salmon come in from the sea, and swim up the rivers which wind their way through the rainforest. The salmon, returning inland to spawn, attract predators, such as bears. Grizzly bears, although once more widespread in the habitat, are now mostly confined to areas north of the Canada-US border. Black bears and their beautiful white subspecies, the Kermode or spirit bear, are present here.
An unusual species found in this habitat is the marbled murrelet. This small seabird feeds mostly on sandeels, and will also feed on other small fish - but what's odd about this marine piscivore is its nesting habits. Most seabirds nest on cliffs, so that they are relatively safe from predators, and so they are beside the sea. However, the close proximity of the rainforest to the ocean has meant that the marbled murrelet has decided to take the jump to nest not on cliffs, but in the forest. It makes nests out of moss and lichen amongst the branches of conifers, sometimes up to 80 km inland!

 By Gus van Vliet (not with USFWS) - [1], Public Domain, 

A marbled murrelet swimming

The Appalachian temperate rainforest can be found in the southern Appalachian Mountains. There are multiple subcategories of forest that can be found within the habitat: at low elevation, mixed woodlands can be found, at middle elevation spruce is predominant, and at high elevation it is fir. The Appalachian rainforest is notable for its high diversity: around 10,000 species can be found here, including several endemic species of vertebrates. There are more than 30 salamanders that can be found here, as the damp envioroment is perfect conditions for them. Most do not have lungs, instead breathing directly through their skin.
There are also 2 species of endemic turtles. Perhaps most predominant are the fungi: there is an estimated 2000 species living here, with many more yet to be identified.

The Valdivian temperate rainforest is located in Chile, with a small part creeping into Argentina. They can easily be told apart from other temperate rainforests discussed so far by the plant life here. Angiosperms are the most predominant trees, but conifers are also present, in the form of monkey puzzles, fitzroyas, and others. Understories consisting of bamboo and ferns can also be found, home to species such as Chusquea quila, an endemic bamboo, and giant rhubarbs.

 By Albh - Own work, CC BY-SA 3.0,
The understory of the Valdivian temperate rainforest

There are a variety of unusual mammals present in this habitat, including the monito del monte. This small marsupial is a nocturnal, arboreal insectivore, occaisonally feeding on fruit. Worryingly, this endearing little mammal is declining, due to deforestation and fragmentation of habitat, and predation by introduced domestic cats. The locals also kill them because they believe they are bad luck, and they think that it causes diseases and is venomous - this has led to incidents such as houses been burnt down simply because this creature was seen inside. In reality, these animals are harmless, but may soon need our help if they are to survive.

 By José Luis Bartheld from Valdivia, Chile - Monito del Monte, CC BY 2.0,
A monito del monte clings to a bit of bamboo

The world's smallest deer, the pudú, is also found here, although it too is threatened. Finally, the smallest cat in the Americas makes its home here: the kodkod, or güiña.

 By Mauro Tammone -, CC BY 3.0,
A kodkod

 The Japanese temperate rainforest is a habitat found on Japanese islands, dominated by firs in alpine areas, and beeches and other broadleaves being predominant in areas of lower elevation. Up to 5300 species of plant can be found in this habitat, 40% of which are endemic to Japan.
Several unique creatures can be found in the Japanese temperate rainforest, such as birds like the black woodpecker, and mammals like the arboreal Japanese dormice, Japanese serow, and Japanese macaques. In the forest streams, the vulnerable Japanese giant salamander can be found.

Of course, this is just a brief look at the temperate rainforests. They are also present in New Zealand, Australia, UK, and elsewhere - but I decided to focus on the examples which were particularly unique, or simply interested me more than the others.

I think that the damp, foggy, dripping, mossy habitat of the temperate rainforest is a wonderful one - and the flora and fauna which live there are fascinating. Unfortunately, they are also threatened by habitat loss and other dangers.
I hope that you have enjoyed this look at the temperate rainforest, a unique and wonderful habitat, and have maybe been inspired to think about rainforests differently.

Until next time, keep on the wild side! 

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