It’s been a while since the last ecology quiz. This month’s puzzle should be a lot simpler than the last one.
A century ago, an irrigation channel, 100s of kilometers long, was built. The channel crossed many creek-lines, altering the natural flow patterns. In the photo above, two creeks run to the north (top). The creek on the left now banks up south of the channel, and a weir wall regulates flows to the north. The weir reduces flows along the creek and affects a string of intermittent wetlands further downstream.
In 1945, when the first air photo was taken, one of these wetlands was bone dry. Large trees were scattered across it, as shown below. Their numbers may have been reduced by earlier clearing, especially in the south-west. The black line east of the wetland is another channel.
In 2006, the wetland was again dry, but was very different to the 1940s. A big dam had been built to the north, the western half was cropped, but the eastern side remained uncleared. In fact, over the 60 year period, plant cover increased greatly in the east, as can be seen in the two photos below.
This month’s quiz is a simple one. Can you guess the name of the species that increased? And can you explain why it increased?
Rather than give a prize to the first correct answer (as I did last time), we’ll see which species is most popular. I’ve suggested ten options in the poll below. Please select an option then click on the Vote button. You can then see which species was most popular by clicking the ‘View Results’ link below the poll.
Please also post a comment to explain why the changes may have occurred or to ask questions. You can view earlier blogs about some of these species by searching for their common names in the search pane to the right.
In the next blog, I’ll provide the answers and discuss the ecology of the area.