Beam Knowledge Rep Sept 04

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Participants

September 21st

Restricted to certain axis; spatial patterns (naturally occuring gradients); abundance; temporal
In a particular control plot, how are things changing, and are those changes in the same trajectory (in the same gradient change)?
Ton of data in range management
Q: Are most of these datasets freely available on the web; are people sharing them? A: Few available on web ... Q: But is it possible to get them? A: It is a very divergent / diverse community. Q: W

September 22nd

Some overlapping stuff on every biodiversity analysis
Methods / Design focus
Analysis focus
Mark: Goal is to compartmentalize that provides general utility for next project, for some other analysis; a standard type of function that we want to capture and describe to use for others
Bob: At one point there was a database with various scripts that provided the full spectrum of data integration

Predicting species response to increased rousource availability (history, questions, dataset)
what happens when you increase productivity (experimentally), and then look at what happens to diversity
N (nitrogen) Fertilization experiments (KBS oldfields, ARC heath)

if you add nitrogen, it generally increases productivity (Gough et al. 2000)
Every experiment found that as you increase productivy it decreases diversity, which doesn't follow the natural productivity/species-richness curve (this is gaining interest: we are increasing productivity of systems in general with environmental change going on, e.g., urbanization increases nitrogen/fertizilation, and a desire to know the result on diversity)
What is Primary Productivity "can of worms"

Want to aggregate data at many different scales / communities to get many types of graphs; you want to ultimately go from smallest possible scale to largest scale
decision making that goes in, before any analysis happens. This goes into the data discovery/integration. Deana: can we build a repository of methodologies.
primarily using herbaceous sites
you do a broad category of the dataset, but not the details (a little bit of woody stuff, ...)
Bob: need a step where someone can look at the methodology ...
Rich: Need to capture what it is you are measuring; it isn't as much a methodology issue
Bob: Clark and Clark paper covers some of this (Bob said he'd dig up the ref)

most of the time, productivity scales well, i.e., it is a linear scaling, e.g., anpp vs. area is a linear relationship. so for exmaple, even though they are smaller plots, you can get g/m^2 measures. Basically, productivity doubles as area doubles...
n addition decresases species diversity: plot at lter sites of anpp (above-ground primary productivity) versus relative species density; species density is the number of species observed in a given area
two studies, measures at different scales: either you simulate or measure a species area curve, and extrapolate to different areas.
N fertilization positivevly effects productivity negatively effects diversity

N fert. interacts with environment; species sorting (dominance composition) negatively effects diversity

in the case of increased fertility, can we predict what species we will lose? What species will become dominant?
are these responses contingent on system characteristics?

dataset: 8 lter sites, 28 community types (mainly vegetation classifications, based on the experiments/manipulations done at the sites); 831 species
dataset characteristics

n added (g/m^2/yr), 10 (ARC), 9.5 (CDR), 60/wk (GCE), etc.
Form of N: NH4-NO3 pellets (ARC), Liguid Urea-N, NH4-NO3 pellets, etc.
Treatment plot size (m^2): differs from 900 to .25
Sample plot size (m^2): .25 to 10 (these don't differ that much really: .32, .30, .25, 1) ... it isn't, however, appropriate to compare directly, without the species area curves, the .3's with the 1's
Replication: 2 to 10
Duration (yrs): 2 to 13

Often times, a matrix like this is constructed at the beginning of doing a "synthesis", and the most important points to track for each site are: treatment, sample size, duration, and replication.

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This particular version was published on 22-Sep-2004 11:00:39 PDT by SDSC.bowers.