18
$\begingroup$

Deserts are defined by their hostility to flora and fauna and a distinct lack of rain. Plains are simply relatively smooth areas of land. My question is how much area would be required to have a shift from a desert area to a plains area? I.E. If I started in a desert and walked in one direction, what is the realistic amount of distance I would have to walk to reach Grassy plains lands? If this is generally too broad then we can assume the dessert is a circle of roughly 4,000 square miles and anything past that border of about 33 miles from the center is no longer a dry and hot place. Could the grasslands start right at that border or would there be a dead zone where rain could fall and temperatures would be fine but little would grow?

$\endgroup$
  • 6
    $\begingroup$ Savanna, central Asia. Also deserts are dry but not neccesarily hot. $\endgroup$ – Mormacil May 8 '17 at 21:58
  • 1
    $\begingroup$ @Mormacil this is the correct answer. If you can elaborate, please do so, as an answer. $\endgroup$ – Mołot May 8 '17 at 22:04
  • $\begingroup$ @Mormacil It does answer one of the questions, what would grow in between, but does not give specifics or answer other parts of the question. $\endgroup$ – William C. May 8 '17 at 22:06
  • $\begingroup$ @WilliamC. hence I made it a comment and not an answer. I hope my answer helps you more. Savanna btw isn't between grassland and a desert, it is a grassland itself. Same goes for the plains in central Asia. $\endgroup$ – Mormacil May 8 '17 at 22:19
  • 1
    $\begingroup$ In some places, it can be just a few steps. For instance parts of the eastern side of the Sierra Nevada. where there's a valley and (not as high) mountains on the other side. The valley has lakes and wetlands that are fed by streams coming off the Sierra, which support grasslands. that are just a few steps from the sagebrush desert. $\endgroup$ – jamesqf May 9 '17 at 3:17
35
$\begingroup$

Consider the Great Sand dunes National Park enter image description here (image credit to national parks service, and in public domain in the USA)

Here an area of sand dunes is adjacent to scrubby grasslands. The dunes are held in place by a number of rivers running off the mountains. The rivers carry sand downstream, then when the rivers enter sink holes, the sand is deposited, and picked up by winds. This forms a region with a classic sandy desert appearance. The rainfall in the region does exceed the 250mm/year normally taken to define "desert" however, the high evaporation rate means that the sands are fully arid.

Beyond the rivers, shrubs and grasses can grow, even though rainfall is low, only about 280mm/year, this is sufficient for drought-tolerant grasses, and of course, the rivers bring additional water.

$\endgroup$
  • $\begingroup$ I love this. I guess you could also have a dryer area (less precipitation, under the 250mm limit) but have more running water in the form of streams meeting the main river providing more hydration to the one side of the river. This would allow the dunes side to be properly classified as desert while not drying out the other side of the river. $\endgroup$ – Baldrickk May 9 '17 at 10:41
  • 2
    $\begingroup$ I was going to say just look at Denver, but this is a pretty similar answer. Though just because there is sand does not mean there is a desert. And just because there is no sand does not mean there is no desert. $\endgroup$ – The Architect May 9 '17 at 16:21
22
$\begingroup$

Flood Plains in Deserts

Consider the Nile flood plain:

Image courtesy to Andrew (Leoboudv), CC BY 2.0, via Wikimedia

The boundary between the desert and fertile land is very dramatic; to answer your question, grassland is literally a step away. Of course, the land is fertile because of flooding, not rainfall, so you have to decide whether this satisfies your criteria for grassy plains lands.

You could object that this is agricultural land, and not a pure grassland per se. Since the flood plain predates human agriculture, though, at least at some point in the past, it must have been a "wild" grassland along the lines you ask for.

Oases

Of course, if we accept that grassy plain does not necessarily require to be fertile because of rainfall, oases are the next obvious answer coming to mind:

Public domain, via Pixabay

Again, the fertile land is directly adjacent to the desert. Increase the amount of water available in the source aquifer, and you can increase the size of the oasis to suit your needs (the biggest oasis in the world is apparently the Al Hasa oasis in Saudi Arabia, 100 km²). Note that the height difference between the desert and the oasis does not need to be so dramatic as in the picture, although some difference is necessary due to the way oases form.

$\endgroup$
  • 1
    $\begingroup$ Welcome to WorldBuilding jaytibann! Interesting answer. If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$ – Secespitus May 9 '17 at 14:22
19
$\begingroup$

Desert

Alright I'll turn it into an answer. So first things first. What is a desert? It's basically a very dry barren terrain. This can range from sandy Saharra to rocky Atacama or Arizona. It can also go from searing hot to cold depending on location. The Gobi desert is known as a cold desert with the occasional snow even.

Grassland

So how far do we need to go before we can find rain again or more important water? Not that far honestly. The aforementioned Gobi Desert is a rain shadow desert. This means mountains block rain for a bit. After that there is normal rain. This is in a way an extreme version of the dry side of a mountain. So on the mountainside you get a desert while in the valley below normal rain is falling. enter image description here There won't be a clear border though. A desert isn't dry or wet. It's a scale, largely dictated by terrain height. I think the shortest distance between full grassland and full desert will either by a rain shadow from a mountain or another form of cliff catching rain all together. Either way it will be a higher terrain blocking clouds.

As I mentioned some deserts here are some grasslands. American prairies, African savannas, plaines in Central Asia and the Steppes in Russia.

$\endgroup$
  • $\begingroup$ And if the land was mostly flat? Would it simply just depend on how far out from a water source they were? $\endgroup$ – William C. May 8 '17 at 23:55
  • 1
    $\begingroup$ @Mormacil the dry valleys in the antarctic are a very good example. It's not rained there in decades, on the other side of the hills, massive ice sheets. en.wikipedia.org/wiki/McMurdo_Dry_Valleys $\endgroup$ – Leliel May 9 '17 at 3:47
  • 5
    $\begingroup$ The massive ice sheets are also in a desert - very little precipitation falls on them, it's just that the ice flows in from a long way a way. $\endgroup$ – Martin Bonner May 9 '17 at 9:00
  • $\begingroup$ There also polar deserts. $\endgroup$ – Hauleth May 10 '17 at 7:43
6
$\begingroup$

Not far at all. Assuming your "grassy plains" defines the biome types of temperate steppe and grass savannah, there are places all over the world where those biomes abut either arid or semi-arid deserts or xeric shrubland.

enter image description here (from Wikipedia)

In this picture above we are looking for yellow areas next to red ones. We can see this happens in multiple places in North America, Asia, and Australia.

In practice these will typically be transition zones, not abrupt borders. But you shouldn't have to go more than a few score miles to be able to tell the difference.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.