Riverine Ecology

[Turtle]

...That ivy can out-compete your native creepers? I'd be in there tearing it out by hand but it's all up the trees too. Does it root to the trees or just climb them. We have a few vines that get pretty bad but if I cut them at ground level they die in the trees. Fast native ground covers will grow even faster with VAM. ...

 

A few words on English Ivy, whether in riverine environments or no. I have battled a bad infestation along the banks of the Columbia River when I rented a place there. I have blogged on it in the Gardening & Horticultural Science thread if I recall.

 

1) The Ivy does not 'root' to trees and take nutirents from them, rather the 'root-like' structures simply secure it to the bark.

 

2) English Ivy has 2 distinct stages: a) the juvenile stage wherin the plant sends out leaders on the ground & up the trees, and in this stage the leaves are lobed. B) the adult stage begins once a leader is sufficiently high in a tree, and the plant then develops oval leaves and begins to flower & produce seed.

 

3) The ivy can add hundreds or even thousands of pounds of additional weight to trees, as well as adding a significantly greater wind-load on a tree by virtue of the abundant (and evergreen) foliage.

 

4) Herbicides have little effect on English Ivy, and removal is primarily by hand. Cut the big stems going up the trees, and that kills everything above the cut. (It takes quite a while to go brown). The juvenile runners have to be dug out and/or pulled up by hand.

 

PS 5) The network of runners on the trees can constrict them, and the network also collects debris which covers the bark & promotes decay and attack by insects.

 

As go the trees, so goes the bank. :beer:

 

In spite of local laws and a County weed control board that dictates homeowners remove this legally declared invasive species, I think few have any awareness, let alone careness, about this wide-sprread problem. :D

[freeztar]

I found this great paper about riparian zones (specifically, stream buffers) and thought I would share it. It's based in Georgia, but the info is general enough to be applicable elsewhere.

 

http://www.agecon.lsu.edu/WaterEconomics/pdf/buffer_litreview.pdf

[Essay]

Great Thread.

Thanks.

[Ahmabeliever]

I still can't find that study. Perhaps they've removed it because it was bollocks ;)

 

Nice links rade. This one that refutes the study I saw where riparian litter was considered insignificant rang a few bells.

 

Falling Leaves Much More Crucial To Stream Health Than Previously Thought, According To New Three-Year Study

 

The article talks about specific species that were not significantly reduced. Also that it was a 3 year study. I believe the earlier NZ study differed because - it was shorter - and, we have a high incidence of heavy rainfall over steep country which flushes out riparian debris at regular intervals. This is typical of NZ country.

 

Also, our aquatic insects are not as diverse as other countries because of these conditions, but apparently highly adaptable with more insects that can travel to and populate other water bodies (ie: a stage of the insect is airborne) when the environment demands it.

 

Which brings us back to evolution, the other thread that started me making comments that ended up in this thread. NZ has unique speciation due to isolation and geographic features. Another Galipagos! ;)

 

Nice link Freeztar. Bit of reading to go yet... I note in the contents what you say is true - no inclusion of benthic life. Still, it's a damn good resource.

[freeztar]

I still can't find that study. Perhaps they've removed it because it was bollocks :eek:

 

Perhaps Dr. Wallace found it? (from the link below)

"I first started thinking about this research when I saw an article that said there is no clear relationship between resources and invertebrate abundance in streams," said Wallace. "And I just didn't believe it. I suggested we test the assumption to find out."

 

Nice links rade. This one that refutes the study I saw where riparian litter was considered insignificant rang a few bells.

 

Falling Leaves Much More Crucial To Stream Health Than Previously Thought, According To New Three-Year Study

 

The article talks about specific species that were not significantly reduced. Also that it was a 3 year study. I believe the earlier NZ study differed because - it was shorter - and, we have a high incidence of heavy rainfall over steep country which flushes out riparian debris at regular intervals. This is typical of NZ country.

Yes, nice links Rade.

Although they don't specifically say so in the article, I think the populations that did not significantly decline were probably those they referred to as the steep moss-covered bedrock areas. It'd be nice to see the paper though so we could see the actual breakdown of species.

 

Also, our aquatic insects are not as diverse as other countries because of these conditions, but apparently highly adaptable with more insects that can travel to and populate other water bodies (ie: a stage of the insect is airborne) when the environment demands it.

Interesting. Have more info on this?

 

Nice link Freeztar. Bit of reading to go yet... I note in the contents what you say is true - no inclusion of benthic life. Still, it's a damn good resource.

 

Yeah, I'm still making my way through it myself. :)

[Ahmabeliever]

Yes I saw the good Dr had read the same material as me, or similar, in the past. There's your evidence sorry I couldn't find the original.

 

Now, NZ as a unique environment....

 

Here ya go, here's a quote from the abstract. There's more of this ilk around but it's a bit off track...

 

http://www.rsnz.org/publish/nzjmfr/1993/32.pdf

 

Here's a quote from the abstract...

 

The international significance of the New

Zealand freshwater macroinvertebrate fauna is

established, existing and potential threats to it are

reviewed, and regional patterns of invertebrate

distribution based on current information are

examined. Distinctive features of international

significance are the poor representation or absence of

some invertebrate groups, a high degree of speciation

amongst other groups, an apparently large number of

primitive species, a high degree of endemicity, and

the southern-most representatives of some cosmopolitan

groups.