DATE=6/25/99

TYPE=AGRICULTURE TODAY #2106

NUMBER=7-32284

TITLE=INSECTS, PLANTS AND CLIMATE CHANGE

BYLINE=ROB SIVAK

TELEPHONE=202-619-2023

DATELINE=WASHINGTON

EDITOR=SMART

CONTENT=

[ATT: INSECTS, PLANTS, ENVIRONMENT, CLIMATE CHANGE]

INTRO: A NEW STUDY CONCLUDES THAT A GLOBAL WARMING EVENT 55

MILLION YEARS AGO TURNED A TEMPERATE REGION OF THE

WESTERN UNITED STATES INTO A LUSH TROPICAL FOREST -- AND

TRIGGERED A SURGE IN PLANT-EATING INSECTS. THE STUDY,

PUBLISHED THIS WEEK IN THE JOURNAL SCIENCE, SUGGESTS A

MORE RAPID WARMING OF THE GLOBAL CLIMATE TODAY COULD

CAUSE MAJOR CHANGES IN THE WAY MODERN PLANTS AND INSECTS

INTERACT. ROB SIVAK HAS DETAILS:

TEXT: CO-AUTHORS PETER WILF AND CONRAD LABANDEIRA

(LAH-BAHN-DARE-UH) -- PALEOBIOLOGISTS WITH THE

SMITHSONIAN'S NATURAL HISTORY MUSEUM IN WASHINGTON, D-C.

-- BASE THEIR STUDY ON PLANT FOSSILS COLLECTED AT

SEVERAL SITES IN SOUTHERN WYOMING. THE FOSSILS DATE FROM

THE COOLER PALEOCENE EPOCH OF 65 TO 58 MILLION YEARS AGO

TO THE MUCH WARMER EOCENE PERIOD, FROM 58 TO 38 MILLION

YEARS AGO. PETER WILF SAYS THAT DURING A THREE

MILLION-YEAR PERIOD OF STILL UNEXPLAINED GLOBAL WARMING

IN THE EARLY EOCENE, THE TEMPERATE-ZONE FLORA OF ANCIENT

WYOMING UNDERWENT A PROFOUND TRANSFORMATION:

TAPE: CUT ONE -- WILF :23

"OVER THIS THREE MILLION YEAR PERIOD, WITH A RISE IN

TEMPERATURE OF ABOUT SEVEN DEGREES CENTIGRADE, THERE

WAS AN EIGHTY PERCENT TURNOVER IN THE FLORA. VERY FEW

THINGS THAT WERE AROUND IN THE COOLER PALEOCENE WERE

STILL AROUND BY THE TIME OF THE THERMAL MAXIMUM. AND THE

OTHER THING THAT HAPPENED WAS THAT THERE WERE MORE KINDS

OF PLANTS. AND NOT ONLY WERE THERE MORE KINDS OF PLANTS

BUT THEIR (MORE) MODERN RELATIVES HAD A MORE TROPICAL

SIGNATURE."

TEXT: AS THE SCIENTISTS PORED OVER THE RICH FOSSIL RECORD OF

THIS CHANGING FLORA, THEY SAW NOT ONLY THE DELICATE CELL

AND VEIN PATTERNS IN THE PETRIFIED LEAVES BUT CLEAR

SIGNS AS WELL OF DAMAGE FROM CATERPILLARS, LEAF MINERS

AND OTHER HERBIVOROUS INSECTS. AND MORE IMPORTANT, SAYS

PETER WILF, THAT INSECT DAMAGE WORSENED MARKEDLY AS THE

CLIMATE BECAME MORE TROPICAL:

TAPE: CUT TWO -- WILF :20

"THE FIRST THING WE SEE IS THAT THE PROBABILITY THAT A

GIVEN LEAF WILL BE CONSUMED IS HIGHER WHEN IT'S WARMER,

ON AVERAGE FOR ALL SPECIES. AND A SECOND THING THAT WE

SEE IS THAT, FOR A PARTICULAR SPECIES, MORE THINGS ARE

EATING IT. SO THERE IS MORE HERBIVORE PRESSURE. AND THIS

MATCHES WHAT WE SEE IN MODERN FORESTS."

TEXT: RESEARCHER CONRAD LABANDEIRA SAYS THE FOSSIL STUDY

OFFERS A CLEAR MESSAGE FOR THOSE CONCERNED ABOUT THE

EFFECTS OF CLIMATE CHANGE ON TODAY'S PLANTS AND ANIMALS:

TAPE: CUT THREE -- LABANDEIRA :18

"ONE THING WE CAN SAY IS WHAT WILL RESULT WHEN WE HAVE

THIS PROFOUND PERTURBATION OF THE CLIMATE. THAT WE CAN

SAY. AND WE CAN SAY THAT THIS IS A PREDICTIVE

CONSEQUENCE OF WHEN YOU HAVE TURNOVER IN THE FLORA, AND

TEMPERATURES INCREASE IN INTENSITY."

TEXT: BUT BOTH RESEARCHERS CAUTION THAT THE CHANGES DOCUMENTED

IN THE FOSSIL RECORD DON'T NECESSARILY PROVIDE A ROADMAP

FOR THE ECOLOGICAL CHANGES THAT COULD BE TRIGGERED BY

HUMAN-INDUCED, AND MUCH MORE RAPID GLOBAL WARMING TODAY.

UNIVERSITY OF UTAH BOTANIST PHYLLIS COLEY, AN EXPERT IN

MODERN FOREST ECOLOGIES, AGREES THAT THE SMITHSONIAN

RESEARCHERS DESCRIBE A UNIQUE, PRE-HUMAN ENVIRONMENT,

WITHOUT DIRECT PARALLEL ON TODAY'S CROWDED PLANET:

TAPE: CUT FOUR -- COLEY :33

"IN THEIR SYSTEM, THERE IS THE OPTION FOR PLANTS AND

ANIMALS TO BOTH MIGRATE AND ALSO ACTUALLY TO EVOLVE, AND

MUCH OF WHAT THEY ARE SEEING IS BASICALLY A

CO-EVOLUTIONARY 'ARMS RACE' IN WHICH BOTH THE HERBIVORES

AND THE PLANTS ARE ADAPTING TO EACH OTHERS' DEFENSES AND

COUNTER-DEFENSES. THERE, WE ARE LOOKING AT THE RESULT OF

EVOLUTION. WHEREAS IN CURRENT GLOBAL CLIMATE CHANGE, WE

ARE SIMPLY GOING TO BE SEEING THE DISRUPTION OVER A VERY

SHORT TIME SCALE OF PLANT-HERBIVORE INTERACTIONS."

TEXT: STILL, PHYLLIS COLEY SAYS THE FOSSIL STUDY PRESENTED BY

PETER WILF AND CONRAD LABANDEIRA SHEDS NEW LIGHT ON THE

DYNAMICS OF TROPICAL FORESTS AND ON HOW

CLIMATE-SENSITIVE PLANT-INSECT RELATIONSHIPS CAN BE.

THOSE RELATIONSHIPS ARE AT THE HEART OF MOST LAND

ECOSYSTEMS AND ARE CRITICAL TO GLOBAL AGRICULTURE. MS.

COLEY SAYS KNOWING HOW PLANTS AND INSECTS CO-EXIST --

WHETHER 55 MILLION YEARS AGO OR TODAY -- IS FUNDAMENTAL

TO UNDERSTANDING LIFE ON EARTH. IN WASHINGTON, I'M ROB

SIVAK.

NEB/RMS/NES

25-Jun-99 2:25 PM EDT (1825 UTC)

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Source: Voice of America