[Tdwg-obs] Survey and Monitoring
jones at nceas.ucsb.edu
Wed Nov 16 00:40:17 CET 2005
The discussion so far has been right on, but I'd like to add a few more
comments about ecological surveys and monitoring. So far the emphasis
has been on single, identifiable species. I fully agree with Lynn's
comment that we also need an emphasis on identification of organisms to
higher taxonomic ranks, functional groupings, life-history stages, and
other ecological classifications.
In ecological survey work there is always a tradeoff between sampling
extent and intensity, and that often results in a desire to lower effort
per sample via either using reduced precision in identification or by
using various subsampling techniques.
Observers don't always identify organisms to species, or they may use
functional groupings or other ecological classifications for their
identifications. I've seen this with people that sample zooplankton
(many copepods are extremely difficult to identify efficiently),
intertidal invertebrates and algae, and forest mosses, among many others.
In addition, within a single sampling location (e.g., a plot or quadrat)
sampling effort often varies depending on the species or maybe some
life history stage. For example, in some forest survey work I've done
the trees above a certain size class are censused, geolocated, and
characterized fully, while below the size cutoff they are only counted.
Shrubs, saplings, and seedlings may be treated differently, and
subsampling may vary among species. Seedlings of abundant species may
be subsampled more than rare species to save time. As a consequence,
any standard needs to be able to associate spatial sampling designs and
subsampling procedures with both taxonomic and other distinguishing
characteristics of the sampled community. This means that records
within a sampling unit (e.g., a plot) and within a species may be
collected using different protocols.
Finally, some methods for estimating abundance (e.g., percent cover)
frequently also count non-organismal features such as substrate (soil,
rock, etc). In both the intertidal zone and forests, surveys might
include % cover of sessile organisms as well as bare rock or other
substrates, and the totals may not add up to 100% where there is 3d
structure. I think we need to accomodate these other categories as they
are critical for analyzing coverage data as it is commonly collected.
Enjoying the discussion,
Denis Lepage wrote:
> Last email from me for tonight, I promise.
>>Overall I like the direction of Denis's proposed definition, but I have a comment and a question.
>>Comment - I propose to explicitly expand the definition of an obervation to include both organisms and ecological communities (such as vegetation).
> Here's a slight change that might work: "An observation is the characterization of the occurrence of an organism (or a community of organisms) through a collection event with a defined protocol and spatiotemporal location. Individual observations are non-independant entities that can be linked to each other through their common characteristics."
> The main difference I see is that in the case of ecological communities, you are not only monitoring occurrence (presence/absence), but also changes in the other characteristics of your community.
> I think providing a separate definition for Monitoring would also be useful. Monitoring and observational data are 2 different things, although they are obviously intertwined (and sometimes confused). In the case of population monitoring, you are interested in changes of abundance of a population over space and time (and you typically use observation events as sample points to infer larger population changes). In the case of community monitoring, you are usually more interested in changes in the ecolological characteristics of a particular area (and you also use observation events to do that).
>>And a question - does the "defined protocol" need to be a
>>published document, or can the protocol be more informal? I
>>think that the observer should provide some minimal
>>documentation of how they made that particular spatiotemporal
>>observation, but I'd imagine there's quite a bit of high
>>quality observation in existence that was collected
>>opportunistically and not necessarily using a published protocol.
> No, defined protocol didn't imply a scientifically rigorous one or a published one. "Casual data collection" could be a defined protocol. I couldn't think of a better term.
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jones at nceas.ucsb.edu Ph: 907-789-0496
National Center for Ecological Analysis and Synthesis (NCEAS)
UC Santa Barbara http://www.nceas.ucsb.edu/ecoinformatics
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