Assessment of final Kroll deer report
Editor's note: The following is an assessment of the deer trustee report written by Timothy Van Deelen, who is an assistant professor of forest and wildlife ecology at UW-Madison. He is an expert in conservation and management of large mammals in the Great Lakes region. Van Deelen had been appointed by the Wisconsin Natural Resources Board as a member of a citizen committees to review Wisconsin’s deer management units alternative deer harvest programs.
This is a preliminary review based on a first-pass reading of the Wisconsin deer trustee’s final report released July 9. There is much in this report that requires further study and discussion, but several people have asked me to provide an initial reaction. Here it is.
It must be said at the outset that I am pleasantly surprised. I was very critical of the lack of scientific content in the preliminary report and, by that standard, the final report is much improved. I outlined my criticisms (letter available at here) and had sent an e-mail raising important concerns early in the process (Jan. 16, 2012), hence I was gratified to see that my concerns were largely addressed in the final report. I have some quibbles, but I appreciate that the committee used the scientific peer-review as something of a model in preparing the final report.
The first 18 or so pages of the final report are a re-statement of the findings of the preliminary report and, as such, contained a restatement of points that I criticized. Thus, for example, the mis-reading of the SAK audit report of 2006 on the topic of SAK precision (the plus or minus 122 percent confidence interval for Wisconsin’s use of SAK, page 11) was included, but was given a fuller and correct treatment (confidence intervals cannot be known, page 21) later on in the final report.
Recommendations regarding population management: In broad strokes the final report recommends a de-emphasis of the use of SAK in the deer management process without abandoning it. This would be accomplished by recommendations for reserving SAK for statewide or regional population estimation, rather than deer management unit (DMU)- level population estimation and using SAK to infer trend (change over a three- to five-year time period) rather than point estimates (population size this year) at the DMU level. These changes would be consistent with recommendations coming out of the 2006 SAK audit report to aggregate DMUs to create large samples of input data. Similarly, the final report recommends doing away with population goals at the DMU-level and, instead, basing harvest levels on judgments about whether landowners, hunters and managers want the DMU-level population to increase, decrease, or stabilize. Judgments would depend on a suite on metrics (e.g. harvest levels, forest impacts, ag damage, car collisions, biodiversity impacts) in addition to deer density that would need to be developed. I found this section to be overly hopeful in terms of the opportunity for addressing deer management controversies because arguments over how many deer there should be would simply be replaced with arguments over what level of deer impacts are tolerable and which metrics should receive priority. Nonetheless, I think it’s better, in principle, to base management on deer impacts (provided they can be measured at the appropriate scale!), rather than numbers because deer number are really only a proxy for deer impacts.
The Final Report is fond of a putative quote from Dr. Robert Holsman (UW-Stevens Point) saying that SAK is indefensible because it’s a blend of science and value judgments (pages 11, 23, 28) – presumably because the value judgements (actually profession judgments about the input parameters) introduce subjectivity. I have discussed use of this quote with Dr. Holsman and it’s important to point out that the “quote” is a mischaracterization of what Dr. Holsman said – both in the language of the quote and in context with which its used in the Final Report. A couple of points. Dr. Holsman is a respected specialist in the human dimensions of wildlife management. His research indicates that most deer hunters don’t understand SAK and don’t really care about its technical issues in any case. However, Dr. Holsman also believes that SAK is too damaged from persistent controversies to be accepted among deer hunters who pay attention whatever its actual performance may be (i.e. indefensible). Dr. Holsman’s work is important and helps explain why the Final Report observes that persistent deer controversies in Wisconsin seem to be driven more by a small group of deer “opinion leaders” in hunter groups, rather than rank-and-file hunters (page 23). But on the value of professional judgment, I think the Final Report is too rigid. It’s true that the SAK, as used in Wisconsin, is a mix of professional judgment and science. Whether it’s diagnosing our diseases, managing our retirement accounts, or selecting a new hunting bow, we routinely rely on the professional judgments of professionals who understand things better than we do by virtue of their training and experience. In fact, Drs. Kroll, Holsman, Guynn, and myself are all professors in university wildlife programs. Much of what we do is geared towards producing professionals who can exercise sound judgments about wildlife on behalf of stakeholders – that’s a good thing (and Dr. Holsman would agree). In fact, use of SAK can be defended. Moreover, there are statistical techniques (Bayesian, simulation) that hold some promise for more rigorously incorporating professional judgments or deer hunter judgments into SAK estimates. This offers some hope that SAK can be improved and made more quantitatively probabilistic. This last point answers the Final Reports criticisms about the SAK being too deterministic. It doesn’t need to be.
Recommendations regarding regulations hunting seasons and bag limits: The Final Report recommends a simplification of hunting regulations and a process by which hunting regulations could change on three- to five-year cycle, rather than on an annual cycle. As a deer hunter, I could support this. As a supporter of responsible management, it’s important to point out that this comes at a cost in terms of being responsive to changing conditions. Other recommendations include raising fees (by minor amounts) for antlerless tags in some cases and limiting antlerless tags in others. The reasons given for these recommendations were a bit unclear, but seemed to focus on addressing hunter concerns that the DNR was somehow devaluing deer by making antlerless permit too readily available. Individually, these measures probably are trivial in terms of their impact on antlerless harvests, but I would be concerned that collectively they would make it more and more difficult to achieve responsible antlerless harvest.
Notably, this section contains a recommendation to “resolve” the baiting and feeding issue and the context (issues raised: deer becoming nocturnal, hunter conflicts, disease) indicate that the trustee’s and committee’s preferred way to resolve the issue is to end the practices. I give this recommendation a full-throated endorsement.
Recommendations regarding predation: The section on predation was the best one in terms of fairly representing the state of knowledge on the topic. The only thing really missing was some discussion of compensatory responses to variation in predation. This would put the accounting for number of deer killed by wolves per year (third paragraph, page 38) in a meaningful context and also provide a mechanism to explain why a literature review suggested no impact of predator control on deer population growth at high density (page 38) and why modeling exercises found only trivial impacts of predation on deer population parameters derived from harvest data in Wisconsin (page 37).
The recommendations coming under this section are particularly relevant right now since Wisconsin’s Natural Resources Board is scheduled to hold a hearing on a proposed wolf hunt on July 17. I whole heartedly endorse recommendations to update Wisconsin’s wolf management plan (No. 3, including meaningful human dimensions research) and to implement a hunt that “should be conservative …” (No. 4, page 42).
Recommendations regarding CWD: Recommendations included a call for more passive management of CWD in southern Wisconsin and I think this is exactly what we are seeing. Notably, the report scolded the DNR for not reacting aggressively enough in response to the discovery of a CWD positive in northern Wisconsin saying that: “A proper approach would have been use of a health check/surveillance team (discussed later) deployed immediately on such a finding. In addition, use of local observers and cooperators to find and report sick or dead deer would have provided a non-lethal first response. Once the geographic context is determined, the appropriate action should be focused, localized eradication.” To me, and except for the non-lethal first response, this sounds pretty close to the approach used in western Dane county when CWD was first discovered and for which the DNR was roundly criticized. Similarly, the trustee and committee members use the analogy of a brushfire in describing the appropriate management response to CWD (page 56). Dr. Thomas Heberlein, in his influential paper (Fire in the Sistine Chapel), severely criticized use of this same analogy by the DNR. Sometimes you can’t win.
Much of the further recommendations for improving landowner relationships, harvest reporting, generation of biological data, herd health monitoring cycle back to recommendations that Wisconsin implement a DMAP program (Deer Management Assistance Program). There is a detailed section that reviews DMAP characteristics in other states and make very specific recommendations for Wisconsin. This section looked to me like it was copied from some other document. The recommendations for minimum property sizes for participation gave me pause (500 to 1,000 acres) because it would exclude most hunter-landowners, but it makes sense at the same time because it’s not meaningful for a landowner to imagine they can manage a discrete deer population on their 40-acre hunting property. Deer home ranges are simply too large. I am not familiar with DMAP, but as with most things that promise to be a solution to a wide range of problems, I’ll need to be convinced.
More generally, the Final Report largely fails to consider what the cumulative impact of all of their recommendations are across Wisconsin’s landscape. Dr. Kroll is especially enthusiastic about “boots on the ground” cooperation between landowners and biologists and I can’t disagree. However, deer populations have impacts that occur at landscape spatial scales and persist through time on the order of hundreds of years. Hence, managers also have a responsibility for the bigger picture. I think it’s reasonable to believe that most DMAP enrollees will choose higher deer densities on their property. If you are a deer hunter, it’s rational to always choose more deer on your property because the benefits accrue to you while the costs may go to the forester down the road, the farmer nearby, the motorist driving up from somewhere else, or the future Wisconsin resident who inherits a landscape with a reduced diversity of wildflowers. The Final Report contains much talk about needing to find shared values between managers and landowners, but managers have a unique responsibility for the public trust management of resources. This responsibility generates a value that I am not convinced will be readily shared or recognized by hunter/ landowners.
Similarly, while the report notes that Wisconsin has higher harvests, more trophy potential, and better recruitment than comparable states, it misses the opportunity to educate hunters on the fact that elementary harvest management theory (McCullough’s [1975, 1984] SY theory) suggests that aggressive harvests are linked to higher sustained harvest, more trophy potential, and higher recruitment. Thus, advocating for more deer (less aggressive harvest) means fewer deer harvested sustainably, reduced trophy potential, and reduced recruitment. This phenomenon is the engine of quality deer management and was a key selling point for Dr. Alt’s reforming of deer policy in Pennsylvania. As McCullough (1984) himself notes, this phenomenon is utterly counterintuitive. But if landowners and hunters really understood the trade-offs involved, they might not be so enthusiastic about ever higher deer numbers.
The report recommends that harvest reporting enter the 21st century with use of electronic and internet-based data gathering at check stations. I concur.
In general again, the Final Report recommends lots of things that are going to place greater demands on DNR staff and likely will require the DNR to divert people and resources from other important things that the DNR does for the people of Wisconsin. Having worked with the deer management program of Wisconsin for many years, I am very familiar with the manager’s dilemma that they could do a much better job on this or that problem given more money, more time, or more personnel. Given the independent sources cited in the Final Report (QDMA, Pope and Young) one could mount a very credible argument that deer hunting in Wisconsin is about as good as it gets in North America. We routinely enjoy higher sustained harvests of both bucks and does and we produce more trophy bucks per unit area than our neighboring states and the other big deer states. Those are cold facts. Notably, the Final Report raises the issue of unrealistic hunter expectations early on (page 8) and then returns to the issue in the final section (Admonition). The first two full paragraphs on page 82 are spot-on and may be the most important points raised in the entire Final Report. I urge anybody reading my comments to go to page 82 of the Final Report and contemplate these paragraphs. I congratulate the trustee and committee members for their wisdom here. This needed to be said.