The mid-Holocene Ulmus fall at Diss Mere, South-East England — disease and human impact?

There are five major hypotheses to explain the apparently synchronous, widespread, spectacular, specific, and sudden elm decline in north-west Europe — climatic change, soil change, competition, human impact, and pathogenic attack. The first four hypotheses predict slow declines (ca. 50–250 years), whereas the pathogen hypothesis predicts a rapid decline (ca. 10–20 years). Pollen analyses of annually laminated sediments from Diss Mere across the elm fall show that the Ulmus decline occurred within 7 years but that there was human impact in the surrounding forest for at least 160 years, including local cereal cultivation for at least 120 years, prior to the elm fall. At the time of the elm decline, there is no evidence for particularly warm or cold seasons or for any additional human interference. The magnitude and rate of the elm pollen decline are consistent with O. Rackham's hypothesis of a pathogenic attack taking place within woodland where the elm trees were already damaged as a result of human activity.

[1]  K. Fægri.  On the introduction of agriculture in western Norway , 1944 .

[2]  S. Fritz.  LAKE DEVELOPMENT AND LIMNOLOGICAL RESPONSE TO PREHISTORIC AND HISTORIC LAND-USE IN DISS, NORFOLK, U.K. , 1989 .

[3]  B. Huntley,et al.  An Atlas of Past and Present Pollen Maps for Europe , 1984 .

[4]  G. Brunskill.  FAYETTEVILLE GREEN LAKE, NEW YORK. II. PRECIPITATION AND SEDIMENTATION OF CALCITE IN A MEROMICTIC LAKE WITH LAMINATED SEDIMENTS1 , 1969 .

[5]  The Ulmus fall at the transition atlanticum-subboreal in pollen diagrams , 1968 .

[6]  A. Smith.  4. THE ATLANTIC–SUB‐BOREAL TRANSITION , 1961 .

[7]  J. Iversen.  The Development of Denmark's Nature since the Last Glacial , 1973 .

[8]  S. Peglar.  The development of the cultural landscape around Diss Mere, Norfolk, UK, during the past 7000 years , 1993 .

[9]  S. Peglar.  The mid-Holocene Ulmus decline at Diss Mere, Norfolk, UK: a year-by-year pollen stratigraphy from annual laminations , 1993 .

[10]  P. Rasmussen.  Leaf-foddering of Livestock in the Neolithic: Archaeobotanical Evidence from Weier, Switzerland , 1989 .

[11]  W. Watts.  3. POST-ATLANTIC FORESTS IN IRELAND , 1961 .

[12]  H. Birks,et al.  Vegetation and Land-Use History at Diss, Norfolk, U.K. , 1989 .

[13]  K. Edwards,et al.  Holocene palynology: II human influence and vegetation change , 1991 .

[14]  J. Iversen.  Problems of the Early Post-Glacial Forest Development in Denmark , 1960 .

[15]  S. A. Sturludóttir,et al.  The elm decline at Pawlaw Mire; an anthropogenic interpretation , 1985 .

[16]  B. Geel,et al.  Early human disturbance of the natural environment recorded in annually laminated sediments of Lake Gosciaz, central Poland , 1992 .

[17]  J. L. Reveal,et al.  Ancient Woodland, Its History, Vegetation and Uses in England , 1980 .