What intrigued me was this statement by Nekola, the author of the review:
Botkin spends almost two chapters talking about how essential disturbance, particularly fire, is to the maintenance of diversity in many USA grassland and conifer forest communities. However, he then chooses to ignore the accumulating empirical evidence documenting catastrophic biodiversity losses across many taxa groups following the reintroduction of fire into reserves (e.g., [8,9]). Such works suggest that the widespread improper use of fire management represent [sic] one of the single most harmful immediate threats to biodiversity within the USA today.”
My first thought was that “he can’t be talking about forests… wouldn’t we have heard about “catastrophic biodiversity losses across many taxa groups?””. And one could assume (perhaps) that wildfires would have similar impacts to prescribed fires? The “single most harmful immediate threat to biodiversity within the USA today.” Whew! On this blog you might think it’s the few surviving lumber mills, or perhaps breaking up habitat with houses, or some people think oil and gas development may make things difficult for the sage grouse.
So my finely tuned feelers went up and I looked at the cites (8 and 9).
Swengel, A.B. (1996) Effects of fire and hay management on the abundance of prairie butterflies. Biological Conservation 76, 73–85.
Nekola, J.C. (2002) Effects of fire management on the richness and
abundance of central North American grassland land snail faunas.
Anim. Biodivers. Conserv. 25, 53–66
I was intrigued by 9 so went to look it up. Here’s the paper and below is the abstract.
Effects of fire management on the richness and abundance of central North American grassland land snail faunas.— The land snail faunas from 72 upland and lowland grassland sites from central North America were analyzed. Sixteen of these had been exposed to fire management within the last 15 years, while the remainder had not. A total of 91,074 individuals in 72 different species were observed. Richness was reduced by approximately 30% on burned sites, while abundance was reduced by 50–90%.
One–way ANOVA of all sites (using management type as the independent variable), a full 2–way ANOVA (using management and grassland type) of all sites, and a 2–way ANOVA limited to 26 sites paired according to their habitat type and geographic location, demonstrated in all cases a highly significant (up to p < 0.0005) reduction in richness and abundance on fire managed sites. Contingency table analysis of individual species demonstrated that 44% experienced a significant reduction in abundance on firemanaged sites. Only six species positively responded to fire. Comparisons of fire response to the general ecological preferences of these species demonstrated that fully 72% of turf–specialists were negatively impacted by fire, while 67% of duff–specialists demonstrated no significant response. These differences were highly significant (p = 0.0006). Thus, frequent use of fire management represents a significant threat to the health and diversity of North American grassland land snail communities. Protecting this fauna will require the preservation of site organic litter layers, which will require the increase of fire return intervals to 15+ years in conjunction with use of more diversified methods to remove woody and invasive plants.
Remember, Nekola said “single most harmful immediate threat to biodiversity within the USA today.” Not to be disrespectful, but did anyone at the journal actually review/edit/read this?
So now to the constancy thing.. if we read “catastrophic biodiversity losses across many taxa groups following the reintroduction of fire into reserves” we have to wonder what the point you are measuring the “loss” from and why. This may be a switch as Botkin points out from the idea of “climatic climax” to “what was there before Europeans was the right condition” to “what is there now is the right condition.”
For non-scientists, just remember scientists make all kinds of claims in their summaries and abstracts (and university press offices add their own spin). You often need to look for yourself for the connection between facts found and conclusions drawn (as we say in the more humble world of administrative appeals). My impression is that when I was growing up in science we were very careful about that link and that our major professors would get on our case if we were not. And I’d say that what’s in the research articles themselves tends to be more careful. It’s when the article is cited that writers claims’ become exaggerated. If claims seem too broad to be true, they are probably leaps of hype. Nowadays it is easy to check in most cases thanks to the internet.