10/22/02

Now for the results from "library" day...

Critical area
I found yet more information on the "critical area" idea. This one actually gave me enough facts that I would feel confident telling other groups that there is no critical area - we need as much area as we can get. According to the article, which documented the results of the Lovejoy experiment in Manuas. After just two year, the large flocks of mixed species birds disapeared in the 1 and 10 hectare square plots. After 10 years, all animals with very large ranges (army ants, bird flocks that follow army ants, and animals like capuchin monkeys) had completely disapeared from even a 100 hectare square. However, the study did give some other useful information. More by accident than anything else, researchers discovered that areas that were surrounded by secondary growth forest retained their species diversity much better than areas that were covered by shrubs or grass. This information came from:
Holmes, Bob. (1998). Life on the Edges.
New Scientist, 151, 38-39.

Use of bats as bioindicators
Amazingly enough, I was able to find an entire paper on the use of bats as bioindicators in Amazon rainforests. The paper didn't use what I consider "practical" means for montioring bats; they misted with four nine meter nets in some odd shape. I think that the bat detectors described here would be a better way of analyzing bat populations. Since different bats use different frequencies, we can tell which kinds of bats are where, and, hopefully, can somehow measure the intensity of sound at a certain frequency. The article also gave several reasons why bats make good indicators:
1. easy to find - lots of species
2. bats occupy just about every consumer trophic level. (Unfortunately, none of them create their own energy. Ain't that sad?)
3. they often select specific habitats
4. they are important to ecological processes - seed dispersal, pollination, insect population
The paper also suggests that bats of the subfamily Phyllostominae are used, as they are very sensative to habitat disturbance.
Medellin, Rodrigo A. (2000). "Bat Diversity and Abundance as Indicators of Disturbance in Neotropical Rain forests." Conservation Biology, 14(6), 1666-1675

Insects
We had been considering using insects as bioindicators, but had somewhat shied away from it because it seemed so difficult. This article agreed with our conclusion, stating that selecting and testing insects as bioindicators is difficult. It also says that there are very few examples of ecologists being able to use insects as reliable bioindicators for conservation and planning.
McGeoch, Melodie A. (1998). "The Selection, Testing, and Application of Terrestrial insects as bioindicators". Biological Reviews of the Cambridge Philosophical Society, 73(2), 181-201.

10/15/02

Source:
http://lba.cptec.inpe.br/lba/indexi.html -> "Biomass fire consumption and carbon release rates of rainforest-clearing experiments conducted in Northern Mato Grosso, Brazil"

experiment: 5 1-ha plots were taken and burned. Each had different characteristics of location and timing of the fire
See figure 2 in paper for the setup
Plots A and B: investigate edge effect with pastures
C: investigate edge effect with forest
D and E: provide differences between two curing periods

Results: Leaving area to dry out for a year before burning it causes the fire to spread faster cleared area with 1, 4, and 9 ha led to co2 release rates of 21%, 41.8%, and 47.5% respectively, with curing periods of three months. An area of 4 ha with a curing period of 15 months released 61.5% of carbon into atmosphere.
Estimate: Carbon release to atmosphere is 69 Mg/ha, for an estimated biomass consumption of 50%

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Source: Biological Dynamics of Forest Fragment Project (http://www.mnh.si.edu/biodiversity/bdffp.htm)

This project was originally started to determine the minimum contiguous area needed to maintain an ecologically stable area. However, as the project progressed, researchers discovered that much more than just land area controlled the stability of an area of forest.

Some effects on edges of fragmented forests:

Decrease in species richness of birds, some insects, primates, bees, and termites. Increase in species richness of small mammals, amphibians, and butterflies Changes in composition of communities of butterflies and small mammals Within taxonomic groups there is a predictable size effect of fragmentation on community evolution Serious structural changes in forest Changes in resource distribution (fruits, and insects) Negative effects on tree survival and leaf fall Animal response to edge is variable Animal response to barrier created by pasture is also variable Importance of matrix habitat for understanding the dynamics of populations and communities in fragments Discovery of second-order effects of isolation: ecological processes (decomposition and pollination) are affected by fragmentation Demonstration of non-applicability of Theory of Island Biogeography to reserve design for amphibians

This creates somewhat of a problem. Other groups have been wanting ideas on how large of an area is necessary to maintain an acceptable level of fauna biodiversity, but this project pretty much says its not possible.

10/13/02

Currently, we have come to the conclusion that pretty much all of our goals fall into two categories, characterizing and montioring. By characterizing, we mean:

creating a template profile for individual species identifying "indicator" species that show the health of the fauna population as a whole determining how much area and base physical condition the environment needs to sustain fauna life (work with air, water, soil, and flora groups on that)

by monitoring we mean:

Determine what needs to be monitored in order to measure population health adapting current monitoring technology to be more effective (or, if needed, creating new monitoring techonlogy)

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