Dear Sol,

Your question appears broadly understandable (there may be a generic consensus that biodiversity, complexity and stability "go together"), but it may also be rather difficult if not impossible to address, as you seem to be trying to relate two poorly defined variables.

You may want first to clarify exactly what you mean by "forest biodiversity" and "vegetation complexity", for instance by narrowing down the scope of these concepts until specific quantitative measurements can be made on each.

At the same time, you seem to be interested in approaching these issues and their inter-relationships from a remote sensing perspective. This would only be possible if one or more variable or process of interest actually affected the transfer of radiation in those environments to such an extent that a "signal" could be detected in those measurements, above and beyond the "noise" of all other processes controlling them.

Lastly, you mention "niche availability", "foliage height density" and "bird species": It is my understanding that different bird species (like insects) may occupy different niches at different heights in the canopy, though these may or may not relate to "foliage height density", or most probably "not only to that canopy property". To the extent "niches" represent "preferred habitats", relevant environmental factors might include solar radiation exposure, temperature (min, max, etc.), protection from precipitation (rain, snow) or wind, safety from predators, access to food, etc.

Once you clarify your operational concepts and limit your inquiry to a more specific question, it will become easier to discuss possible relations between essential variables and to explore whether remote sensing may contribute to the investigation.

I hope this helps. Cheers, Michel.

FHD can be seen as a measure of vegetation complexity. Bird richness and related diversity metrics are one way of enumerating forest biodiversity. You could examine if relationship exists between these two. Please see this link too: http://ausable.org/images/uploads/general/ResearchPPT_LW.pdf

Mixed model effect using R also might be interesting!

Logistic regression modelling in R is useful for this approach.

Simpson index and Shanon Winer index areuseful for this approach

Hi. You can contact Dr. Trevor Price, he is working on birds diversity and speciation in Himalayas. Attached is his latest work.

Thanks for the helpful advice everyone, this has been really useful.

I'm working on the effect of Growing Space (small grown gaps) Spatial Pattern (in 2D) on understory vegetation diversity (shannon diversity index). GSSP can be easily derived from lidar or very high resolution images (better if infra-red).

Results seem promising! Remind me in a couple of month and I'll send you results (hopefully a published article).

It could be interesting to apply this approach also to animal community diversity.

Good luck

Ugo 

Dear Sol Milne,

As suggestion, take a look in some statistics that I used in my article: Xaud et al. 2013.

Tropical forest degradation by mega-fires in the northern Brazilian Amazon

http://www.sciencedirect.com/science/article/pii/S0378112712007128

Forest Ecology and Management

Volume 294, 15 April 2013, Pages 97–106. doi:10.1016/j.foreco.2012.11.036

You can get a preprint copy in my hp at Researchgate

researchgate.net/profile/Haron_Xaud

Best Wishes,

Haron Xaud