I'm interested in the differences between wet and dry seasons in tropical rainforest in general and Papua New Guinea in particular.

https://en.wikipedia.org/wiki/Wet_season says

Dry and rainy months are characteristic of tropical seasonal forests: in contrast to tropical rainforests, which do not have dry or wet seasons, since their rainfall is equally distributed throughout the year.

My immediate reaction was that this cannot possibly be true, e.g. I have seen videos of the water level in the Amazon basin rise and fall by double-digit meters in wet versus dry season. But it does carve out an exception for 'tropical seasonal forests'; maybe the author is using some unusual terminology where 'tropical rainforest' is used much more narrowly than is usual?

According to https://weatherspark.com/y/144392/Average-Weather-in-Port-Moresby-Papua-New-Guinea-Year-Round

Port Moresby experiences extreme seasonal variation in monthly rainfall. Rain falls throughout the year in Port Moresby. The month with the most rain in Port Moresby is March, with an average rainfall of 190 millimetres. The month with the least rain in Port Moresby is September, with an average rainfall of 20 millimetres.

So there is definitely a big difference between wet and dry season in amount of rainfall. What implications does this have?

I've seen documentaries of wet versus dry season in the African savanna, and there are large visible differences in the amount of water on the ground, in the effects on vegetation and animal behavior, which are well summarized here: https://www.armstrongsafaris.com/post/what-are-the-differences-between-the-rainy-season-and-the-dry-season

But from looking at videos of New Guinea and other tropical rainforests, there are no such visible differences. Aside from the aforementioned change in water level in the Amazon basin, I haven't seen any visible differences whatsoever. But it seems intuitively and by analogy, that such a big difference in rainfall, should make some difference.

So what actual effect does wet versus dry season have on the ground, apart from probability of being rained on? Does it change animal behavior? Do trees tend to produce fruit in one season rather than the other? Are there other differences I'm not thinking of?


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Browse other questions tagged or ask your own question.