Here we present the first chironomid-inferred summer-temperature reconstruction for the late Holocene in the Netherlands. A core segment from lake Uddelermeer (Figure A) covering the period 2500 cal. yr. BP to 400 cal. yr. BP was analysed on a high-resolution for organic content, pollen, spores and NPPs (Figure B), and subfossil chironomid remains (Figure C). (Figure D). In the C-IT record, we could identify the presence of a cold Iron Age (IA), the Roman Warm Period (RWP), the Dark Age Cold Period (DACP) and the
Medieval Warm Period (MWP), with a 1.5 °C temperature drop from the RWP to the DACP. These warm and cold periods have been identified in a range of proxy records throughout NW Europe indicating a regional
climate trend (Figure E). In the record from lake Uddelemeer the DACP seems contemporaneous with a reforestation phase (Figure D) which is recognized in numerous palynological records throughout the
Netherlands and is commonly linked to a drop in population density following the decline of the Roman
Empire (Figure F). Additionally, this period appears to be characterized by large scale landscape changes in the Netherlands (Figure F). The timing of all these changes might suggest that climate developments had an (in)direct influence on landscape developments and cultural trends. The results of this study are presented in Gouw-Bouman et al. (revised/accepted ) Late Holocene ecological shifts and chironomid-inferred summer temperature changes reconstructed from lake Uddelermeer, the Netherlands. Palaeo3
Marjolein T.I.J. Gouw-Bouman 1 , Nelleke van Asch 2 , Stefan Engels 3 & Wim Z. Hoek 1
The Dark Age Cold Period
recorded in lake sediments in the Netherlands
B
100
150
200
250
300
350
400
450
500
550
Depth(cm)
400
600 800 1000
1200
1400
1600
1800
2000 2200 2400
Age (Cal. yr
.BP )
20
%
Endochironomus
albipennis-type
20 40
Lauterborniella
Parachironomus varus-type
20
Polypedilumnub eculosum
-type
Chironomini larvae
20
Microtendipes
pedellus-type
Polypedilumnub ifer-type
Dicrotendipes notatus-type
Pagastiellaorophila Dicrotendipes
nervosus-type
Polypedilumsordens-type Stenochironomus
Glyptotendipespallens-type Endochironomus tendens-type
Chironomus plum
osus-type
Cladopelmalateralis-type Dem
icryptochironomus Endochironomus
impar-type
Chironomus
anthracinus-type
Cryptochironomus Tribelos
Stictochironomus
20
Cladotanytarsus
mancus-type
20
Pseudochironomus
20
Tanytarsuspallidicornis-type
20
Tanytarsusmendax-type
Paratanytarsuspenicillatus-type Tanytarsusnemorosus-type
Tanytarsusgracilentus-type
20 40
Parakiefferiellabathoph ila-type
20
Corynoneuraedwardsi-type Psectrocladiussordidellus-type
Limnophyes/ Paralimnophyes Cricotopus
laricom alis-type
Pseudosmittia/ G eorthocladius
Cricotopus type P
Acamptocladius Heterotanytarsus
Cricotopus
intersectus-type
Pseudorthocladius Smittia/ P
arasmittia
Cricotopus obnixus-type
Psectrocladiuspsilop terus-type
Smittia/ P
arasmittia /Paracricotopus
Nanocladius
branchicolus-type
Cricotopus trifasciatus-type
20
Procladius
20
Ablabesmyia Zavrelim
yia
Chironomidae indet.
Tanypodinae ind
et
Tanytarsiniind et
Orthocladiinae indet
50 10 0 15 0 20 0
Headcapsules /sample
Zone
Ch2
Ch1d
Ch1c
Ch1b
Ch1a
Chironomini Tanytarsini Orthocladiinae Tanypodinae
Analyses N. van Asch, S. Engels & M. Wolma
Lithology
Green gy t t ja Bro wn-green gy t t ja Bro wn gy t t ja
Frequency (%)
C
E F
B Pollen, spores and chironomids (Figure C) indicate that the lake was mesotrophic and sustained a Littorellion in the period 2500 to 1140 cal. yr. From 1140 cal. yr. BP onward a shift to green gyttja coincides with an algal bloom indicating a shift from clear-water mesotrophic conditions to eutrophic turbid conditions in the lake. The temperature reconstruction from the eutrophic part of the profile is deemed unreliable. A reforestation is visible in zone Pb mainly attributable to Quercus, Fagus and Alnus. An increase in Cannabis-type in the top part of the core is related to hemp retting in the lake .
C The chironomid assemblage was mostly dominated by littoral species associated with
macrophytes such as Lauterborniella, Cladotanytarsus mancus-type and Parakiefferiella bathophila- type. The shift to high-nutrient conditions dominated by algae at 1140 cal. yr. BP is reflected in the
chironomid assemblage by increases in eurytopic taxa, such as Procladius and Ablabesmyia which are resistant to disturbances.
Location of lake Uddelermeer in the Netherlands (a) and LIDAR elevation map of the area around the lake (b)
1: lake Uddelermeer 2: lake Bleekemeer
3: Medieval fort 4: Brook
A
D
E NW European temperature reconstructions
A: C-IT, lake Uddelermeer NL (Figure D)
B: C-IT, Bigland Tarn UK (Barber et al. 2013) C: Tree ring inferred, Alps (Büntgen et al. 2011)
D: Compilation various records (Riechelmann & Gouw-Bouman 2019)
E: Compilation various records, N Hemisphere (Ljungqvist 2009) F: Compilation various records, global (Helama et al. 2017)
F Overview of events
IA: Iron Age; ROM: Roman period; EMA: Early Middle Ages Climate: C-IT lake Uddelermeer.
People: populations density in the Netherlands (Groenewoudt & van Lanen, 2018).
Forest: averaged Arboreal pollen percentages various records from the Netherlands.
Landscape: geomorphological changes (Pierik, 2017).
References
Barber K., Brown A., Langdon P., Hughes P. (2013) Comparing and cross-validating lake and bog palaeoclimatic records: A review and a new 5,000 year chironomid-inferred temperature record from northern England. Journal of Paleolimnology 49:497-512.
Büntgen U., Tegel W., Nicolussi K., McCormick M., Frank D., Trouet V., Kaplan J.O., Herzig F., Heussner K.U., Wanner H., Luterbacher J., Esper J. (2011) 2500 years of European climate variability and human susceptibility. Science 331:578-582.
Groenewoudt B.J., van Lanen R.J. (2018) Diverging decline. Reconstructing and validating (post-)Roman population trends (AD 0-1000) in the Rhine-Meuse delta (the Netherlands). Post Classical Archaeologies 8:30
Heiri O., Brooks S.J., Birks H.J.B., Lotter A.F. (2011) A 274-lake calibration data-set and inference model for chironomid-based summer air temperature reconstruction in Europe. Quaternary Science Reviews
Helama S., Jones P.D., Briffa K.R. (2017) Dark Ages Cold Period: A literature review and directions for future research. The Holocene 27:1600-1606
Ljungqvist F.C. (2009) Temperature proxy records covering the last two millennia: a tabular and visual overview. Geografiska Annaler: Series A, Physical Geography 91:11-29
Pierik H.J. (2017) Past human-landscape interactions in the Netherlands: Reconstructions from sand belt to coastal-delta plain for the first millennium AD. vol 139. Utrecht studies in earth sciences.
Utrecht University.
Riechelmann D., Gouw-Bouman M.T.I.J. (2019) Climate during the first millennium AD in NW Europe: a review of climate reconstructions from terrestrial archives. Quaternary Research 91:111-131
100
150
200
250
300
350
400
450
500 300
500
700 900
1100
1300
1500
1700
1900
2100
2300
20 40 60 80 20 40 60 80 100 20 40 20 20 20 20 20 40 20 40 20
409 432 208 334 26 58 59 58 90 174 348 357 318 366 409 317 392 313 368 358 288 367 342 313 353 310 328 312 353 373 391 340 373 273 309 321 312 337 363 320 334 339 318 319 325 312 328 302 334 321 345 314 342 348 324 347 354 355 338 350 293 317 337 322 323 355 296 326 334 317
20 40 60 20 40 60 80 100 20 20 20 20 40 60 20 50 100 150 50 100 150 200 100 200 300 400 500 20 20
Pd
Pc
Pb
Pa
Upland herbs Heather Cereals Marsh and swamp Aquatics Fungi
Analyses M.T.I.J. Gouw-Bouman
Green gyttja Brown-green gyttja brown dy
1 Utrecht University, Faculty of Geosciences, Dept. of Physical Geography, the Netherlands.
m.t.i.j.gouw-bouman@uu.nl; w.z.hoek@uu.nl
2 ADC Archeoprojecten, Amersfoort, the Netherlands, N.vanasch@archeologie.nl
3 Birkbeck University of London, Department of Geography,UK s.engels@bbk.ac.uk
D Temperature and vegetation. The chironomid-inferred July air temperature (C-IT) record was produced using a Norwegian-Swiss chironomid-climate calibration dataset (Heiri et al., 2011)
