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PROCEEDINGS OF THE NORAC SIXTH Georeferencing | Abundance Indices | BBS Data Use | Proceedings contents list GEOREFERENCING Tim O'Connell There is strong potential for linking GAP analysis with atlas work. What else can we do with atlas data?
Problems
DISCUSSION Makes sense to come up with list of habitats that need special effort Extensive mining in areas of Pennsylvania have created water quality problems that have affected LOWA distribution. Mark Wimer: If we have a species distribution map and habitat distribution map, which way should it go? If there is a high level of effort and an absence means something, atlas data can be used to correct the habitat model. Overlaying potential habitat and current distribution on maps can help to direct field efforts. Kim Smith: No GAP projects received funding for vertebrate distribution ground truthing. Atlas projects provide excellent opportunities to ground truth GAP information on birds, which probably over-estimates distributions. Washington overlaid GAP vegetation data and atlas data. Chris Elphick: Nevada selected blocks stratified by vegetation, with simultaneous ground truthing of vegetation map. They hope to use this information to create models and develop probabilities of species occurrence in blocks not sampled, based on vegetation occurrence. Hugh Kingery: Habitat data collection is important because species may be using more habitats than the literature suggests, or may be not occurring in some habitats where literature says they occur. There also may be geographic differences in habitat use. Charlie Smith: Vegetation and bird data need to be in the same temporal scale. Not all animals occupy all the habitats they are known to use. NY can produce two lists of help to the next round of atlasers - species known to be there during the last atlas, and species predicted to be there by GAP analysis, based on vegetation. Chair: Charles Francis Understanding abundance is important at habitat and geographic scales. British approach is to correlate abundance with frequency of occurrence. Ontario is considering having counts of species in given area surveyed. DISCUSSION Ted Floyd: Agrees that abundance data is better than just presence/absence, but feels it complicates presentation and statistical analysis. Charles Francis: The product is a database, a book can present any subset of data you want. Statistics dealing with abundance data easier than that for presence/absence data. Ted Floyd - Volunteers won't understand what it will be used for, or how it will be used in atlas, which is what they care about. It needs to be presented in the atlas. Charlie Smith: It is important to ask what you want to learn from this data that you can't get from another source. Different states and provinces have different needs. Need to consult with a biometrician before beginning if you are going to collect it. Abundance is the most challenging question we have to answer in wildlife biology. Garbage in, garbage out. Charles Francis: With presence/absence data, absence doesn't mean anything. Rick West: Britain used absolute abundances, but we seem to be talking about relative abundance. If so, mini-routes like Maryland did seem to be a good approach. Charles Francis: British estimates of absolute abundance are not very precise. One could have a double sampling scheme and get absolute abundance on a subset of sites and extrapolate. Any sampling scheme we come up with to get absolute abundance would have to use a tiered sampling scheme. We are most likely to get relative abundance data. Joan Walsh: Probably not all volunteers would want to collect abundance data or be good at it, but a subset would be willing to do it and would do a good job. Could have some people doing mini-routes to get this data rather than trying to get everyone to do it. Mike Cadman: When you do timed surveys, you need people with equivalent skills. One of the joys of atlasing is that people with lower skills can still participate, it just takes them longer. Joan Walsh: There would need to be training for mini-routes. Doug Kibbe: You wouldn't get equivalent results from all observers. I agree with the others who have spoken. Have you considered using pre-determined abundance categories? Charles Francis: Another approach they were considering is keeping a daily checklist. The accumulated checklists for a block gives a relative measure of abundance by number of checklists with a given species. Another approach is to estimate species numbers on each trip. Hugh Kingery: Habitat matters! It is most efficient to go to areas of a block with the greatest variety of species. This ignores the high numbers of widespread species in the remainder of the block where habitat is more homogeneous. Charlie Smith: At the state level, the proportion of blocks occupied is highly correlated with BBS data for relative abundances. Doug Gross: Cautionary notes from experience as a coordinator in rural Pennsylvania. People may be overestimating the number of people who will participate. Many birders aren't interested in atlasing. I'm concerned that if we get too engrossed with numbers we will turn off potential participants. Mark Wimer: We used orders of magnitude as an estimate of what was in the entire square, but it can be hard to tell what to do with it. The reality of atlasing is that people return to given areas. Every region has heroes, and if we take that person away to do counting or some other technique, it may cause a problem in getting regular block coverage. It is more important to get to out-of-the way places and survey for species under-represented in BBS. Ted Floyd: If there is a positive correlation between frequency and abundance and if the primary goal is prediction of occurrence in areas not surveyed, you don't need abundance data unless there is very fine-grained heterogeneity of habitat. Charlie: There are now extensive requirements for gaining access to private lands. We will be restricted to roadside surveys or written permission, which is big change from last atlas. This will restrict much atlasing to public lands and roadside observations. People do atlasing because it is fun and easy. If we make it too complicated if won't be fun. Chris Elphick: I don't think numbers need to be part of an atlasing effort. This can be accomplished by other means. Dan Brauning: One thing atlases do is push participants' competence to higher levels. Is abundance data meaningful at the scale at which it would be collected? Charles Francis: If participants recorded numbers and scale Christmas Count style, it can be flexible and useful. Abundance data can be atlas-specific. Projects can make it optional to collect this data, but if the database is centralized it needs to be able to accommodate it. Dan Brauning: Projects can just use the folks willing to go above and beyond to collect this data, and not require everyone to do it. Charles Francis: If observers submit day sheets we don't need a summary sheet. We need a database structure that allows participants to record what they are willing to record, above and beyond core data. In Australia, it can be either presence/absence or numbers. Mike Cadman: Atlas camaraderie is important with everyone working on the same thing together. We don't want to dilute this. Charles Francis: It is a marketing issue, and can be a tiered approach. There are flexible ways of getting more information out of atlasers without taxing all of them by using a two-tiered approach. Ontario will be grappling with this topic and others can listen in on the discussion by e-mail. back to top | proceedings contents list BBS DATA AND ITS
USE TO Presented by Keith Pardiek BBS history
Methodology
Past uses of BBS data by atlas projects
Atlas limitations of BBS data
What BBS can provide
DISCUSSION Kim Smith: BBS data from Arkansas was used to test distributions in Arkansas habitat models. Routes were buffered routes for errors. Predictability for some species was terrible, but for others was 100 percent correct. Can use BBS data with atlas data to check accuracy of BBS. Bruce Peterjohn: Some species are better served than others by BBS because of their biology. Carol Foss: Documenting which species are not accurately covered by the BBS could help to discourage inappropriate use of BBS data for other purposes. back to top | proceedings contents list The NORAC website is hosted and maintained by Bird Studies Canada |
