[Taxacom] Satellite images and invertebrate data points

Bob Mesibov mesibov at southcom.com.au
Wed Dec 6 16:48:32 CST 2006

Donat Agosti wrote:

"In this connect, I would also recommend that however does now, or plans to
do fieldwork, keeps a bit of a satellite image, if possible as close to the
date of the collection, projects the gps record on it to assure, the point
is in the habitat she was working in. If this is properly archived with the
necessary metadata, colleague in the future could not only get a point, but
also a piece of landcover and thus do some much more advanced studies."

I have been layering collecting points (and failed-search) points on 
satellite images for PowerPoint talks on "salvage sampling" of native 
invertebrates. My audiences always seem surprised at how little natural 
habitat remains for these animals. This is even true for people who know the 
area covered by the images. People seem to have a more subjective mental map 
on which tiny natural patches are larger, and the agricultural portions 
smaller, than is really the case.

I have also been collecting time-series of aerial photographs. In my field 
areas, these almost always show a substantial _increase_ in the coverage of 
native vegetation over the past 50-60 years. However, many of the expanded 
native areas have depauperate invertebrate faunas. The reason is historical. 
Almost the whole of the landscape in these areas was foolishly cleared and 
burned for agricultural development in the late 19th century. As time 
passed, patches unsuitable for agriculture were allowed to revegetate 
naturally, and in more enlightened times (since about 1975) some patches 
have been deliberately revegetated with natives. Invertebrates surviving in 
isolated remnants have been unable to recolonise these "new" and expanding 
patches because the distances are too great and the barriers 
(pasture/cropland) too difficult.

Thus some of the good-looking patches on today's satellite images have only 
my failed-search points. History "overrides" habitat as documented by 
satellite. For more on this issue, see

Lunt, I.D. & Spooner, P.G. 2005. Using historical ecology to understand 
patterns of diversity in fragmented agricultural landscapes. Journal of 
Biogeography 32(11): 1859-1873.

Dr Robert Mesibov
Honorary Research Associate, Queen Victoria Museum and Art Gallery
and School of Zoology, University of Tasmania
Home contact: PO Box 101, Penguin, Tasmania, Australia 7316
(03) 64371195; 61 3 64371195

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