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Listen to part of a lecture in a plant ecology class.
聽一段植物生態學課程。
So far we have covered biodiversity in the hard wood forest here in the upper peninsula of Michigan from a number of angles.
目前為止，我們已經從多個角度講了密歇根上部半島闊葉林中的生物多樣性。
We've looked at everything from how biodiversity relates to species stability, to competition for forests resources and more.
我們已經講完全部內容了，從生物多樣性是怎樣聯系到物種穩定性，到競爭森林資源等。
But now I want to discuss what's called pedodiversity.
今天我想講講土壤多樣性。
Pedodiversity is basically soil diversity.
土壤多樣性即土壤的多樣性。
When we analyze pedodiversity within an area, we are measuring how much variability there is in soil properties and how many different types of soil there are in a particular area .
我們分析某個地區的土壤多樣性時，我們會測量土壤性質有多少可變性，及在某個地區內有多少種不同的土壤類型。
So we look at soil chemistry, for example, how much nitrogen or magnesium there's in the soil in one spot.
我們來看看土壤的化學性質，比如說，在某個地方的土壤里有多少氮和鎂。
And we compare it with the chemistry of the soil a short distance away.
然后我們將其與附近土壤的化學性質作比較。
Until recently, there hasn't been a whole lot of attention paid to pedodiversity.
直到最近，人們才開始關注土壤多樣性。
But that's changing rapidly.
但情況迅速改變。
More and more studies are being done in these fields.
越來越多人在此領域做研究。
There's a link between biodiversity and pedodiversity, an obvious relationship between soils and flora and fauna, which is why pedodiversity really should be considered in forest management .
生物多樣性和土壤多樣性之間是有聯系的，土壤和動植物之間的關系也非常明顯，這就是為什么在森林管理中，土壤多樣性也需要考慮在內。
A high degree of soil variability in a small area is common, particularly within forests.
小范圍地區內的土壤變化程度很高是很常見的，特別是在森林中。
If you compare soils from a forest with soils that don't come from a forest, the amount of variability will most likely be greater in the forest's soil.
如果你比較森林土壤和非森林土壤，前者的變化程度很可能更高。
It generally has more diversity.
一般森林土壤更多樣。
Um...OK. There are three main causes of pedodiversity within old-growth forest here in our region of Michigan.
在我們所處的密歇根區域的老齡森林中，造成土壤多樣性的原因主要有三。
One is tree species.
一是樹種。
Different species have different influences on soil formation and soil properties.
不同的樹種對土壤成分和土壤性質有不同的影響。
For example, pine trees drop pine needles.
比如說，松樹會掉落松針。
And those needles add a lot of acid to the soil.
這些松針給土壤增加了不少酸性。
The organic litter of another tree species might add less acid but more of something else.
另一種樹產生的有機廢物可能不會給土壤增加這么多酸性，但會增加別的東西。
A lot of different types of trees in an area might mean more pedodiversity.
若在某個區域有很多種不同的樹，很有可能意味著這兒的土壤多樣性程度很高。
Another cause? Gaps ... created when trees fall.
另一個原因？空地，當樹木倒下后就會產生空地。
You see, where there are gaps, open areas in the forest, the soil there changes.
在森林中有空地（開放區域）時，那兒的土壤就會發生改變。
Um... for instance, without a tree to absorb radiation from the Sun, to offer shade, the full intensity of that radiation reaches the ground.
舉個例子吧，（如果）沒有樹來吸收太陽輻射，沒有樹遮陰，太陽輻射以最大強度到達地面。
The soil where the tree used to be heats up.
樹木曾經所在地的土壤就會升溫。
And without a tree to soak up moisture from the ground, the soil remains wetter than in the surrounding forest.
而且沒有了樹來吸收地里的水分，這兒的土壤就會比周圍森林（的土壤）更濕潤。
