Science, Math, and Marbled Murrelets
I am trying to understand a scientific report on the population trend of the marbled murrelet. The report I am reading is the Marbled Murrelet Effectiveness Monitoring, Northwest Forest Plan: 2011 and 2012 summary report. This is the ungainly title of a 27- page report by the Northwest Forest Plan Interagency Regional Monitoring Program. Within in the confines of this blog, I am going to call this report the "Report" and its author, "Falxa et al." Gary Falxa is the Marbled Murrelet Module Lead and the "et al" are the ten other scientist-authors of this report.
Though I have shortened its name, I imagine you are not interested in the Report by Falxa et al. I was told it contains some good news for the marbled murrelet--that population numbers for 2011 and 2012 showed a slight increase. I would like to stop telling people that the murrelet populations in California, Oregon, and Washington have declined 29% between 2001 and 2010 (which, in fact, they did) and that the trend is continuing downward. But I have a problem: the meat of the Report by Falxa et al goes like this (ellipses indicate where parenthetical citations and references to tables occur):
"Population demographic models predicted population declines of 3 to 7 percent per year for the listed range, which includes Zone 6...Miller et al. (2012) reported a statistically significant decline of 3.7 percent per year for the combined population of Conservation Zones 1 through 5 for the 2001-2010 period. For the new analysis based on 2001-2012 data, no trend was detected at the 5 percent leve... While the trend line slope for this period is slightly negative...the 95 percent confidence interval for the trend slope includes zero... which also indicates no statistically significant trend. The reason for finding no significant trend through 2012, when Miller et al (2012) found a declining trend through 2010, is the increased estimate of murrelet abundance for both 2011 and 2012. In 2011, estimates of murrelet population size increased in all conservation zones except Zone 2, compared to estimates from recent years. In 2012, population estimates remained higher in some zones, most notably Stratum 1 of Zone 1 (Strait of Juan de Fuca, Washington), and the 2012 population estimate for all conservation zones combined (Washington south to San Francisco Bay) also remained above that of recent years, in large part an effect of the increase in Zone 1...."
"The sampling error associated with population estimates for such a mobile and patchily distributed species could have contributed to the increased estimates, as could other factors. Results of murrelet population monitoring in 2013 and beyond will help further clarify populations status and trend, as will explorations underway."
I thought by typing out the meaty paragraph above while reading it aloud to myself would increase my comprehension and have me rushing off to the store for a bottle of celebrator champagne. It did not.
I was frustrated and, after multiple readings, set the report aside and picked up the latest issue of Orion magazine. I quickly flipped to Derrick Jensen's "Upping the Stakes" column which, I think Jensen may have written after reading the Report by Falxa et al. It's about simple math and our planet-destroying unwillingness to embrace it. Here is some of what he writes:
"I know if there are 6 billion passenger pigeons and you subtract 1 billion, and then another billion, and keep subtracting them fast than the can add to their own population, then eventually there will be none. I know if there are uncountable salmon and you reduce their numbers to where you can count them, and they you keep subtracting, eventually there will be none....I know the same is true for native forests reduced from 100 percent to 2 percent, and for native grasslands and wetlands reduced to the same extent.
"I also know that if you take the number 315 (as in parts per million) and keeping adding to it, eventually you will get to 350. And if you keep adding to that, you'll bet to 400. And if you keep adding to that you'll get some approximation of hell."
"I don't understand why so many of us don't seem capable of subtracting and adding. Oh, sure, I understand that people come up with lots of rationalizations for avoiding simple math and they come up with lots of fancy names and algorithms to attempt to convince themselves that 100 minus 90 doesn't equal 10, or that 315 plus 85 doesn't equal 400, but whether you call it "managing forests," "generating hydroelectric power," "developing natural resources," "sustainable development," or any of a thousand other names, the subtraction and the addition continue."
It would be folly, given what we've done to our forests and oceans in the past few hundred years to think that the marbled murrelet was on the road to recovery. The scientists themselves cannot quite explain the murrelets' 2011 and 2012 population bump (and a "bump" is what some are calling it). The trend analysis at the end of the Report is full of questions. Were the population estimates the result of sampling error? Has the distribution (not the population) of the birds changed? Did functions of the model change between years? Did survey effort vary? Were more murrelets on the water in 2011 and 2012 because they were not in the forest on nests?
Nowhere is this question: Are we finally managing our forests to improve breeding success of marbled murrelets? Have our paltry restrictions on gillnetting somehow saved enough murrelets to increase the population? Have our aquatic reserves and shoreline management plans actually worked to protect the fish murrelet eat? Have more and more chicks successfully fledged because our spotty predator-control measures are paying off?
Let's not fool ourselves. Let's not pat ourselves on the back for an enigmatic "bump. " We have reduced our original old-growth coastal forests by 80 to 95% in the Pacific Northwest. Scientists who documented the 29% decline in murrelet populations between 2001 and 2010 noted that "[t]hese declines coincide with the reductions in the amount of nesting habitat." So...are we not looking at a corresponding and eventual 80-95% reduction in murrelets? Unfortunately, we cannot know how many murrelets there were "originally," so the question becomes 80 to 95 % of what?
Given that we are logging and losing more murrelet nesting habitat every year--and failing spectacularly at growing any new forests for future murrelets...well, it's simple math and, sadly, we seem all too willing to accept zero as the answer. But the sooner we embrace the possibility of zero, the sooner we can begin changing the equation.