The New Scientist, a well-reputed science magazine, ran an editorial recently headed, “Let’s put an end to biosentimentality.”
It argued that “While a few introduced species have wreaked havoc, some biologists argue that most increase biodiversity, both directly and by spurring evolution.” It points out that a large number of extinctions within the next century are essentially inevitable and we “cannot be choosy about future sources of diversity.”
Eucalyptus is not one of the species that “wreak havoc” – despite numerous myths to the contrary. Far from invading native areas, a study showed that in fact tree cover declined in several Bay area parks in the 60 years ending 1997. It is a victim of fires, rather than a major contributor; the fires start in the exceedingly flammable grass and shrublands. It does not kill birds by beak-gumming, as some people have argued. It does not kill plants growing beneath it through excessive allelopathy… and so on.
The ecosystem on Mt Sutro is a very special one, with a large number of plant species and bird species, and an unstudied number of reptiles, small mammals, fungi, and insects. It’s easy to fail to recognize what is there, since it hasn’t been properly studied. But a knee-jerk conversion to native plants and a fragmenting of this treasure, a forest that looks, feels like an old-growth functional cloud forest and ecosystem will reduce biodiversity, not increase it.