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ALERT - December 4, 2006: Protect Our Woods joins allies to submit a response to the Draft Supplement to the Final Environmental Impact Statement (FEIS) for the German Ridge Restoration Project in Hoosier National ForestPart 20d. Indiana bat (Part 4 of 5)No Continued Supply of Roost TreesAnother problem is what will happen to the logged areas in the future. While the bats are now using them, what about in 5 or 10 years? What happens when the understories grow up? Will that interfere with the use of roosts? What impact does removing most of the big trees have on the site’s ability to produce a continual supply of roosts trees? Any large tree removed will never die and become a potential roost tree. What impact does this have on the bats? MacGregor’s data demonstrate that the bats avoid clearcuts: General forest was used by roosting Indiana bats at 1.5 to 2 times expected levels based on availability, making this a preferred roosting habitat for the bats. All roost trees that were found in general forest were in stands 50 years old or older, and most roosts were fairly large snags that once formed part of the overstory, in live overstory white oaks, or in natural canopy gaps created by ice, wind, or fire damage. This indicates that it may often take 50 years or longer for an even-aged stand to acquire characteristics (snags of suitable size, natural gaps and irregularities in the canopy, etc.) that provide good roosting habitat for Indiana bats. Clearcuts less that 35 years old made up a substantial part of the Indiana bat monitoring area (about 17%) during both years but received no roosting use by transmittered Indiana bats. The fact that young clearcuts were avoided as roosting habitat for Indiana bats was not surprising since there were virtually no snags available in these areas. Yet the draft claims, without any reference to a study, “even-aged management that includes provisions for snag retention may be used.” Draft at 31. Even-aged management is either clear cuts or two step clear cuts. When the snags blow over, the area is no longer suitable, as even-aged management does not provide a continual supply of roosts trees. It is interesting to note that when one looks at MacGregor’s results a pattern emerges. The higher the number of big trees in an area, the more the bats used it. Clear-cuts had no use, old style shelterwood cuts had almost no use, new style shelterwood had the next most use, and closed canopy forest had the most use. When you think about this, it makes sense to say that the more trees in the area, the more likely there will be suitable roosts. The plan should state “the more the big trees the better.” Canopy Closure Readings Are Misused We would also point out that many of the canopy closure readings are misused. To the bats, it is not how much sun reaches the forest floor where the canopy closure readings are taken. What matters is how much sun reaches the part of the tree that they are roosting in. Trees in a closed canopy forest can have more than enough sun for the bats. When a tree dies, it is exposed to the sun. Many trees that are taller than the surrounding trees die. When they die, they have 100% exposure to the sun. Likewise, sometimes trees die in groups, or a storm will come through and open areas. We often see claims that mature forests have 100% canopy closure. This is simply not true. Trees die and create canopy openings. Storms and other natural disturbances also create openings in the canopy. Lethal Temperatures for Bats The plan also needs to address lethal temperatures for the bats. In southern Illinois, lethal temperatures have been measured in roost trees. Thus, cutting trees to provide more sun on a tree could make the tree unsuitable for roosting.” Importance of Reproductive Success This brings up the issue of reproductive success. Many times claims are made that since the bats are using an area, it is good habitat for them. This conclusion cannot be drawn without looking at reproductive success and survival. This is particularly true for a species in a population collapse. As has been documented in numerous studies on birds, the mere presence of individuals in a habitat does not automatically mean that the population is stable or increasing. In fact, areas can function as ecological traps - luring individuals into the area, but then subjecting them and their reproductive habits to the many dangers of parasitism and predation. For example, bats could be found in an area where they are not successfully reproducing or surviving the season. What happens if someone concludes that since the bats are present, it must be good habitat, and then manages other areas bats could be in to be like the ecological trap? The Hoosier Plan and EIS doesn’t even mention reproductive success of Indiana bats, and does not propose or devise any ways to attempt to identify existing colonies and to determine what the reproductive success of the individual colonies is. It is literally going to be impossible, under the current draft, to determine what factors control or significantly influence reproductive success. Our discussions with Dr. Whitaker has indicated there where ways to determine reproductive success for the bats. The plan’s failure to address this at all is a clear error. What the plan needs to focus on, and which is totally deficient from the plan, is a method which will result in the identification and delineation of the existing colonies. Once those colonies are identified, comprehensive studies need to be undertaken to determine which maternity colonies are stable or increasing and which are ecological traps. It is only through this process that the recovery team and the USFWS will be able to determine which habitat factors significantly affect reproductive success. Click here for Part 20 e. Indiana bat (Part 5 of 5)Protect Our Woods
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