Floral Splendour and Shortage of Nutrients - Soil: Reflections on the Basis of our Existence - page 41

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The flytrap. Plants that live in extremely nitrogen-deprived environments must adapt to survive.
The sticky leaves of this alpine butterwort have captured insects that the plant's enzymes will
slowly dissolve to provide a much-needed nitrogen supplement. Another carnivorous plant is the
marsh-dwelling sundew

to the surface, the leathery leaves and aromatic scent confirming the presence
of Rhododendron lapponicum —one of only two wild rhododendron species in
Sweden. In due course I found Alpine arnica, Arctic bellflower, and Arctic white
heather, three calcareous soil species. Joakim's mood began to lift. The highlight
came when we found Alpine butterwort, an insect-eating plant that evolved its car-
nivorous habits as a dietary supplement in nitrogen-poor soil. Alpine butterwort
is a low-growing plant with sticky leaves which trap insects and slowly dissolve
them with digestive enzymes. It is said that you can make sour milk from alpine
butterwort if you mash the leaves with a wooden spoon and add milk.
Eagle eyes are sometimes needed to spot nature's nuggets. But the more one
understands the interplay between soil and plants, the more one appreciates the
subtle changes that occur—changes that generally elude the layperson.
I learned a lot about horticulture when I spent a summer at Capellag￥rden
School in the village of Lilla Vickleby on the Baltic island of Öland. While I pot-
tered about in the vegetable patch, the other students would paint watercolours
of the unique Öland landscape, and the shifting colours of their work reminded
me of the light that Claes Grundsten so ably captured in his Sarek photographs.
The plaintive whistle of the golden plover can be heard in both places, and while
the Montagu's harriers that frequent Öland's agricultural landscape occur only in
southern Sweden, their elegant flight and narrow wings reminded me of the long-
tailed skuas I saw at Pielavalta.
The carpet of flowers is more vivid on Öland than on Sarek's hillsides. Öland's
limestone plateau, or alvar , is topped by calcareous soil that in early summer is
ablaze with orchids including Adam and Eve, military and burnt-tip.
A plant ecologist might be reluctant to label classic Öland specialties like
hoary rock-rose or fern-leaf dropwort as calcareous flora, even though they
grow exclusively on chalk and limestone soil. It is not the chalk or limestone
that holds the key here, but the calcium ions that drive phosphorus from the soil
solution when they form insoluble compounds with phosphate ions. Species like
dock and speedwell, which avoid calcareous soil, quickly suffer the effects of
phosphorus deficiency if they germinate in calcareous soil, in contrast to typical
alvar species which have adapted to life in calcium-rich earth by being able to
absorb phosphorus even when it is in short supply. Dock will, however, thrive
in topsoil from which calcium has leached due to acidic rainwater, and in such
conditions can pose a threat to other alvar-dependent species. Many calcareous
sandy steppe areas in the eastern Sk￥ne region of southernmost Sweden have
suffered degradation of this sort, though efforts to remove the topsoil or restore
calcium-rich soil to the upper layer have successfully benefited the calcareous
grassland flora.