Deceptive Beauties: The World of Wild Orchids - Hardcover

Ziegler, Christian

Hardcover

ISBN 10: 0226982971 ISBN 13: 9780226982977

Publisher: University of Chicago Press, 2011

Synopsis

Confucius called them the “king of fragrant plants,” and John Ruskin condemned them as “prurient apparitions.” Across the centuries, orchids have captivated us with their elaborate exoticism, their powerful perfumes, and their sublime seductiveness.

But the disquieting beauty of orchids is an unplanned marvel of evolution, and the story of orchids is as captivating as any novel. As acclaimed writer Michael Pollan and National Geographic photographer Christian Ziegler spin tales of orchid conquest in Deceptive Beauties: The World of Wild Orchids, we learn how these flowers can survive and thrive in the harshest of environments, from tropical cloud forests to the Arctic, from semi-deserts to rocky mountainsides; how their shapes, colors, and scents are, as Darwin put it, “beautiful contrivances” meant to dupe pollinating male insects in the strangest ways. What other flowers, after all, can mimic the pheromones and even appearance of female insects, so much so that some male bees prefer sex with the orchids over sex with their own kind?

            And insects aren’t the only ones to fall for the orchids’ charms. Since the “orchidelirium” of the Victorian era, humans have braved the wilds to search them out and devoted copious amounts of time and money propagating and hybridizing, nurturing and simply gazing at them. This astonishing book features over 150 unprecedented color photographs taken by Christian Ziegler himself as he trekked through wilderness on five continents to capture the diversity and magnificence of orchids in their natural habitats. His intimate and astonishing images allow us to appreciate up close nature’s most intoxicating and deceptive beauties.

About this title

About the Author

Christian Ziegler is a biologist-turned-photographer specializing in tropical natural history. He is a frequent contributor to National Geographic Magazine, GEO, and Smithsonian, among others. He is an associate for communication with the Smithsonian Tropical Research Institute and a founding fellow of the International League of Conservation photographers.

Excerpt. © Reprinted by permission. All rights reserved.

DECEPTIVE BEAUTIES

The World of Wild Orchids

By CHRISTIAN ZIEGLER

THE UNIVERSITY OF CHICAGO PRESS

Copyright © 2013 Christian Ziegler
All rights reserved.

ISBN: 978-0-226-98297-7

Contents

Foreword by Natalie Angier.................................................
12
Introduction by Michael Pollan.............................................
21
1 ADAPTATION...............................................................
35
2 DIVERSITY................................................................
95
3 POLLINATION..............................................................
137
BIBLIOGRAPHY...............................................................
179
SPECIES INDEX..............................................................
181
ACKNOWLEDGMENTS............................................................
182
RESOURCES / CREDITS........................................................
184

Excerpt

CHAPTER 1

ADAPTATION

They captivate with their beauty and seemingfragility, yet orchids belong to one of thehardiest, most adaptable plant families on Earth.With some 80 million years of evolution in theirpast, they've evolved to survive and thrive ina host of habitats, from semideserts to humidmangrove marshes, from the high hot canopyof tropical forests to the barren coldness ofarctic tundra.

AN EVOLVING STORY

As a young naturalist growing up in southwest Germany, I was enthralled byorchids. To me, they were wondrous, exotic, and rare. When I roamed the earlysummer hills in search of wildlife and plants, spotting an orchid was alwaysa particular thrill. I had learned where to look for them from a neighbor who was verybotanically inclined. He knew the exact places along roadways where little patches oforchids flourished, despite the fact that they had no business being there. He guessedthat they had arrived at their particular spot when the road was being built and a bit oflimestone soil containing orchid seeds had found its way into the road margins. Sincemany of these terrestrial orchids need limestone, I would also look for them in sward—sparse,poor meadowland that drains well. Orchids, I soon realized, had flowers thatdidn't look like other flowers, and various species of these lovely, delicate works of naturecould thrive in almost any environment, from rocky barren sward to shady wetlands.

I clearly remember a college field trip to a rolling grassland not far from myuniversity. We had come at exactly the right week in late May and found a good dozenspecies of pink orchids of the genus Orchis in the south-facing sward. Then we walkedup the meadow toward the vast Palatinate Forest, which runs all the way to the borderwith France, and there in the half-shade of the beeches along the forest edge were thedelicate orchids called little white forest birds. Going deeper into the Palatinate, wefound swamp orchids by a creek and in dark patches of woodland, brown orchids withnone of the chlorophyll that gives most plants their greenness. This variety, called thebird's-nest orchid, lives off the nutrients it receives from a symbiotic fungus.

No other plant family held quite the same fascination for me as orchids did, maybebecause of their relative rareness in northern Europe and certainly because of theirunusual appearance—their delicate shapes and configuration, the deep spurs that hidetheir nectar. They weren't structured like any other flowers, and they seemed somehowspecial in a mysterious way.

As the radius of my wanderings expanded, I had the opportunity to see someamazing orchid habitats across Europe. On a backpacking trip into the Swiss AlpsI saw orchids in abundance for the first time. I was astonished at the profusion oftheir blooms across the high mountain meadows, their pink spikes glowing amiddozens of other summer flowers and all of it backdropped by snow-capped peaks. Itwas breathtaking. There were at least a dozen species in those meadows, includingthe pyramid orchid that Charles Darwin had studied and written about. An orchidenthusiast himself, Darwin gathered wild orchids near his home in Kent andpropagated them. In fact, orchids inspired some of his most critical thinking onnatural selection. In his book The Various Contrivances by Which Orchids Are Fertilised byInsects, he explains the co-evolution of insects and orchids and calls them "amongst themost singular and most modified forms in the vegetable kingdom."

I shared Darwin's enthusiasm for these "singular" creatures, and on hikes I tookinto the Pyrenees, southern Italy, and Greece, I discovered a whole new realm of orchidspecies that I had not seen before. Some of them were oddly shaped, mimicking beesand other insects, while others grew to amazing sizes and had a sweet, honeyed scent.

In graduate school, on botanical research expeditions in the tropics of Asia, Africa,and Panama, I began to realize how narrow the European range of orchids was. Tropicalorchids seemed nothing like the ground-based European varieties I had known.Almost all orchid species in the warm rain forests lived as epiphytes, growing fromother plants, often high up in the canopy. The shapes, colors, and, in many cases, thescents, were out of this world. Their diversity seemed endless; hardly ever would I findtwo individuals of the same species.

My experience with orchids mirrors the global patterns of orchid distribution.While temperate areas tend to have fewer species and predominantly terrestrial ones,tropical orchids are much more diverse and most are epiphytic. Central Europe hasabout 250 species of orchids, yet Panama, barely one-tenth the size, has more than 1,300known species, with many newly discovered ones being reported every year.

That's typical of the difference between tropical and temperate places worldwide, andthe explanation for this lies deep in the Earth's past, in its geology and weather patterns.

KEEPING AHEAD OF CLIMATE CHANGE

For the 3.5 billion years that life has existed on Earth, this has been a warm planet,meaning most life probably evolved under conditions even warmer than what nowexists in tropical areas. The giant fern and horsetail forests that prevailed some 36oto 300 million years ago in the Carboniferous period evolved and flourished in a hot,moist climate. Over the course of many millions of years the organic deposits fromthese plants created the carbon fossil fuels—coal and oil—that we rely on today.

Modern flowering plants began to emerge about 140 million years ago in theCretaceous period. By 100 million years ago, they had diversified widely, probably coevolvingwith insects—the insects pollinating the flowers and the flowers feeding theinsects. The first orchids are thought to have appeared around 80 million years ago,among the flowering plants of the tropical forests. It's amazing to think of orchids as coexistingwith dinosaurs and yet the two shared the planet for a good 15 million years.

The tropical forests of today have existed and evolved without major interruptionsfor millions of years. Some, like the rain forests in parts of Africa and South America,date back an astonishing 65 million years. Of course they started with a differentand less diverse set of species, but these ancient, persisting habitats are more likelyto preserve species over time. That's why the majority of orchid species still inhabitthe tropics. And the greater number of potential pollinator species in these forestshas probably added to the orchids' evolutionary potential, accounting for the speciesrichness closer to the Equator, while the numbers drop off sharply toward the poles.

In contrast, temperate habitats are much younger and have been subject to moreintense temperature variations that can occur even yearly. Orchids have survived onlyas terrestrial species, so they can retreat underground during inclement seasons.

Climatic changes have occurred throughout the Earth's history, and they've neverbeen evenly distributed, always affecting the poles much more than areas close tothe Equator. Today, in fact, the polar regions of Earth are warming up at an alarmingrate, while the increase in temperature is happening at a much slower pace closer tothe Equator. During past periods of cooling, large areas of the temperate zone—a goodpart of which lies in the present-day United States, northern and western Europe, andChina—also cooled down significantly and were often covered with huge glaciers. Mostspecies could cope with the gradual cooling of the planet, but the glaciation events werefar more challenging, driving species and whole ecosystems south. In the past 500,000years alone, there have been five such periods of glaciation, and once each ended, lifehad to start virtually from scratch in the north.

Central Europe, the region that I grew up in, has been hit especially hard byglaciation-induced extinctions, even by temperate zone standards. Fossils fromMessel, a famous site close to Frankfurt in central Germany, point to the existence of avery diverse tropical forest there about 5o million years ago. Similar to what we find inBorneo today, this species-rich community included a wide variety of plant life, as wellas crocodiles, monkeys, and many bat, bird, and large insect species. Since then, theentire planet has cooled and, due to the movement of tectonic plates, Europe has glidednorth about 800 miles (1,300 kilometers). Over time, the ecosystems and many of thespecies of tropical Europe have migrated toward the Equator.

These European migrants faced a serious challenge as they moved south: the Alps.Other continents have north-south-running mountain systems, but this east-westbarrier often proved fatal for species on the retreat from approaching glaciations.Time and again, species got pushed against the Alps, and only the ones that could movefast enough to escape the ice and cold survived.

In plants these kinds of migrations require different processes than they do inanimals. While animals for the most part can move as individuals under their ownsteam—walking, flying, swimming—plants have to find different solutions. Themovement of plants takes place across generations, with each generation taking a singlestep, if the conditions are right. The movement phase in the life of plants is not in theadults, who are firmly set in a single place, but in the seeds. Seeds can cover amazingdistances, many miles sometimes. The agents of transport can be abiotic, such as windor water. More often animals take the role of dispersers, and seeds can travel longdistances in the fur, feathers, or guts of animals. Wherever the seed is transported,it will attempt to germinate. But only those that end up in a habitat with just the rightconditions become successful individuals of the next generation.

Imagine that a colder period is descending on the Northern Hemisphere. Overseveral hundreds or thousands of years, the average temperature slowly drops. For theplants of any given species adapted to that ecosystem, conditions keep getting worse onthe northern edge of the area, while they keep getting better toward the south. Seedsthat have been dispersed northward are less likely to be successful than the ones thatend up toward the south. So the distribution of the species in this ecosystem is slowly,step by step with each generation, shifting toward the south.

It's obvious under this scenario that different plant species will have very differenttravel speeds, depending mostly on how long it takes them to produce a new generationand on their average seed-dispersal distance. While annuals disperse every yearfrom their first year on and thus are able to respond quickly to climate changes,trees might have a generation time of ten or more years and can take a step only thatoften. This generally means that trees are slower responders to climate change thanannuals, but in fact some trees make up for the long generation time by having efficientlong-distance seed dispersal. In the case of epiphytic orchids, the plants bear hugequantities of minute, almost microscopic seeds that can be dispersed great distancesby the wind. That allows for rapid transit and the opportunity to colonize new habitats.

Plants and plant communities flow north and south over time, following the everchanging climate. If climate change is very rapid, as it is now, some or even manyspecies might not be able to move fast enough. They'll get run over by the changingconditions and sink into extinction.

The glaciations of the last million years have significantly influenced all Earth'stemperate ecosystems. After all, a mere 15,000 years ago large areas of North Americaand Europe were covered with ice sheets. The temperate species of today eithermigrated up from the south or originated from protected habitat islands that were notice-covered. The orchids of Europe and North America seem to be a mix of both.

As to the long-lived tropical forests, the periods of Earth's cooling had far lessimpact on them, manifesting mostly as a reduction in rainfall rather than a dropin temperature. In fact, the periods of cooling may have acted as "species pumps"—encouragingnew species to evolve. Here's how it worked: Reduced rainfall turnedparts of the jungle into savannah, interrupted by "islands" of forest. The habitatfragmentation isolated plant and animal species in these island communities, wherethey evolved new species. That helps explain the richness of flora and fauna in thetropics today and the vast diversity of orchids found there.

THE HIGH LIFE

The orchid family is exceptional, probably uniquely so, in its ecological diversity and itsability to tolerate environmental stresses of various kinds, especially a lack of nutrientsand water. Members of the orchid family are able to live in a range of habitats—fromsemideserts to the moistest forests. Some species inhabit swamps and can even live asfloating aquatic plants, while others flourish in alpine meadows and arctic tundra. Evenwhen shrubs and trees have petered out in the harsher northern temperate zone or athigh altitude, there are orchid species that hang on. In fact, orchids thrive in extremehabitats, pushing the edges of where plant life can exist on the planet.

Many orchids have evolved into epiphytes, plants that use others for structuralsupport without being parasitic. Epiphytes have no connection to the ground and musttherefore cover all their nutritional needs while attached to another plant. An estimated72 percent of orchids, or 15,000 to 20,000 species, live in the canopies of rain forests,making them the plant family with the highest number of epiphytic members.

The epiphytic life form probably evolved in the orchid family many timesindependently, because the ancestral orchids had a set of important pre-adaptationsthat equipped them for life in the treetops and in other marginal habitats. Amongthese pre-adaptations were their drought resistance; their low nutrient requirements;their special, more water-efficient type of photosynthesis; and their ability to producehuge numbers of tiny, easily dispersed seeds. The big disadvantage of the epiphyticexistence is the disconnection from the ground and thus from a steady and reliablesupply of nutrients and, most crucially, water.

Despite the fact that tropical rain forests receive abundant rain, the livingenvironment of an epiphyte high in the canopy can resemble a desert, with the stress ofextreme heat, radiation, and photo bombardment from the sun. All epiphytic orchidshave evolved a number of adaptations to cope with these conditions. Most have leatheryleaves with a thick outer wax layer that reduces water loss and also protects the plantfrom the intense UV that could destroy proteins and DNA. They also have a modifiedroot system, the roots covered with a spongelike layer of dead tissue called velamen.When it rains, the epiphytes' velamen captures water and stores it—an adaptation to therare, short, and heavy downpours that occur in the dry seasons of tropical rain forests.Another water-storage adaptation among orchids is their thickened stems, calledpseudobulbs, which store enough water to get the plant through a dry season. Orchidsthat produce pseudobulbs grow new ones each year.

While living high up in the canopy can have its stresses, this place in the sun isalso the greatest advantage of the epiphytes. With very little investment in a stem,these plants have access to sunlight and can concentrate on gathering it with almostall their tissue. A tree, in contrast, has to invest a lot more to get its own leaves intothe sun. Abundant sunshine is very beneficial for the process of photosynthesis, inwhich carbon (from atmospheric carbon dioxide) is captured by the plant. Probablythe most important and sophisticated adaptation in orchids is their way of doingphotosynthesis—a process called CAM, for Crassulacean Acid Metabolism. Thedefining feature of CAM is the ability to take CO₂ from the atmosphere at nightand store it until day, when the energy of sunlight is available to turn carbon intosugars. On a molecular level, this happens when electrons are knocked free by thelight and stored in energy-transporting molecules—much like the process in asolar panel. These molecules then provide the energy to build sugars from CO₂ andwater. So CAM allows orchids to keep their leaf openings closed in the daytime, thussignificantly reducing the loss of water.

Many scientists see these adaptations as a major reason for the impressivediversification of the orchid family. Drought resistance and low nutrient requirementsenabled the terrestrial orchids of the temperate zones to colonize such difficult habitatsas rocky, porous karst landscapes or nutrient-poor meadows and to diversify there. Asto the tropical epiphytes, the ancestral orchid forms were able to conquer an almostempty habitat: the branches of the canopy. Over time, via mechanisms like the repeatedfragmentation of the forest environment and co-evolution with pollinators, theseancestral forms radiated into the stunning array of orchids that we encounter today.

TEMPERATE FORESTS OF AUSTRALIA

The dry forests and woodlands of Western Australiaharbor a rich diversity of terrestrial orchids. Many ofthese eucalyptus-dominated forests frequently experiencefires that clear out the undergrowth and create idealconditions for orchids to be found by their pollinators.

EXTREME TROPICAL HABITATS

Along Caribbean coastlines, mangrove forests oftendefine the transition from ocean to land. From anorchid's perspective, these forests present a verychallenging habitat because of their high salinity andradiation and their limited freshwater. Still, someepiphytic orchids have conquered this special habitatand can be quite common in mangrove stands.

KARST HABITATS

Karst landscapes are difficult habitats for all plants.The Swiss cheese–like soils, composed of limestoneor old lava flows, drain extremely fast, so waterfrom rainfall runs off rather than being absorbed.Orchids, with their adaptations to drought, areespecially suited to this kind of habitat and canthrive in karst grasslands.

MACCHIA HABITAT

Winter rains and summer heat blanket some areasaround the Mediterranean in southern Europe,giving rise to a challenging plant habitat calledmacchia. Similar to the dense, low shrublands ofNorth American chaparral, macchia has poor, oftenlimy soil and limited water—ideal conditions for animpressive number of orchid species.

(Continues...)

Excerpted from DECEPTIVE BEAUTIES by CHRISTIAN ZIEGLER. Copyright © 2013 by Christian Ziegler. Excerpted by permission of THE UNIVERSITY OF CHICAGO PRESS.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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Edition details

• Publisher: University of Chicago Press
• Publication date: 2011
• Language: English
• ISBN 10: 0226982971
• ISBN 13: 9780226982977
• Binding: Hardcover
• Number of pages: 184