RESEARCH: OUTCOMES, VIEWPOINTS & PERSPECTIVES

Combining pollen analysis with the records of cryptogam spores and non-pollen palynomorphs

The combination of pollen analysis with the records of cryptogam spores and other non-pollen palynomorphs has shown to be valuable for detailed reconstructions of the changing local environment of Quaternary sites from northern Europe.

In studies of palaeoclimatic reconstruction, it is of paramount importance to elucidate whether limnological changes correlate to events of vegetation change. However, research on non-pollen palynomorphs has formed little or no part of studies of the majority of Quaternary palynologists from southern Europe.

See examples of the valuable use of this approach in deposits from southern Spain:

CAÑADA DE LA CRUZ (38º 04' N, 2º 42' W, 1595 m a.s.l.). Shallow lake situated in a high-altitude mountain valley within the Sierra de Segura, Betic Cordillera. The pollen sequence has provided insights into the vegetation history of the region since c. 8320 yr BP. Abrupt changes in abundance of the pollen dominants are shown at about 7770 yr BP, 3370 yr BP, 2630 yr BP, 1525 yr BP, and 790 yr BP. The stratigraphy of palaeolimnological indicators is compatible with climatic control of vegetation stages. Zones C1, C3, and, to a lesser extent, C5, characterized by Closterium and Type 128, and increased minerogenic influx, may represent stages with comparatively poor-nutrient water in the context of low temperatures, and short summers leading to treeless catchment vegetation. In contrast, zones C2, C4, and C6, with characteristic Zygnemataceae-dominated assemblages, decomposing fungi, and hygrophyte pollen would represent moderate eutrophication and temporary colonisation of the lake by marginal vegetation within a more forested landscape and milder climate.
( SEE POLLEN DIAGRAMS OF THE HOLOCENE SITE OF CAÑADA DE LA CRUZ: CAÑADA I, CAÑADA II, CAÑADA III)

CANAL DE NAVARRÉS (39º 06' N, 0º 41' W, 225 m a.s.l.). Tectonic, endorheic valley, 1 to 2 km wide, running NW-SE in the limits of the Iberian Cordillera, province of Valencia, easter Spain. An upper lithological unit was formed under continuous sedimentation processes in a shallow lacustrine environment. Several pollen phases have been reported from the study of this section, the last one covering the period from c. 30,900 to 3160 yr BP. Above 145 cm, there is evidence of a change in the trophic conditions, shallow water and plant advancement into the lake, as shown by the curves of Cyperaceae, some fungal types (Type 359 and Glomus) and Zygnema-type. During N3PC, Type 128 and Closterium diminish and Botryococcus and zygnemataceous zygospores (Zygnema first and Spirogyra afterwards) increase. During N3PD, there are indicators of increased colonization of the lake margins and peat decomposition (e.g. pollen of Cyperaceae, Typha, Apium, spores of terrestrial ferns, fungal types like Gelasinospora, Fusiformisporites, Polyadosporites, Glomus).
( SEE POLLEN DIAGRAMS OF NAVARRES AND INTERPRETATION: NAVARRÉS I, NAVARRÉS II, NAVARRÉS III, NAVARRÉS IV, NAVARRÉS INTEPRETATION, NAVARRÉS LATEGLACIAL)

The algal succession observed since the Lateglacial is remarkable, and is characterized by the following assemblages: (N3PB) Types 128-Closterium-Botryococcus, (N3PC) Zygnema-Spirogyra-Botryococcus, (N3PD) Zygnema-Spirogyra-Mougeotia-Rivularia-Chara. This succession may be certainly related with a trophic change to increased alkalinization and concentration of oxidizable organic compounds in relatively warm water. Types 179, 983, 984, and 985 parallel this distribution, with the very abundant Type 983 showing a peak just when maxima for Quercus and Chara hispida are recorded. This Type must be related with a shallow freshwater lake environment. Finally there is an important increase of angiosperm seeds, notably Juncus articulatus, which suggests partial infilling.

VILLAVERDE (2º 22' W, 38º 48', 870 m.a.s.l.). Tufaceous peat deposit, 57 km west of the city of Albacete. The pollen stratigraphy has been used to infer past vegetation changes from c. 8700 to 1230 uncalibrated 14C yr BP within a well-defined catchment area that represents boundary conditions for semi-arid, plateau and mountain vegetation. The variations of the lithology suggest fluctuating water levels with the deposition of marls during periods of higher lake levels and the deposition of peats associated with advances of littoral emergent vegetation during lower lake levels. Associated microfossil assemblages (VM3, VM5) fit into this picture. The association Closterium-Type 128 may be characteristic of mesotrophic stages in lake hydroseres of the region. Type 119 and pollen of aquatic angiosperms (e.g. Potamogeton, Myriophyllum) correlate to this association. During short periods in VM2, and stages VM4, VM6, and VM7, there must have been increased organic input associated with lowered water levels. Increased turbidity would have diminished the reproductive capability of aquatic angiosperms and charophytes carpeting the bottom of the lake. Characteristic microfossil assemblages include Zygnematales, Rivularia, Types 182, 179, Glomus, and Polyadosporites. Together these palynomorphs suggest advances of peat- and sapropel-producing marsh environments, areas of temporary stagnant water and lake eutrophication. In comparison with the sapropelic VM2 and VM4 zones, the peats VM6 and VM7 appear to be formed under more terrestrial conditions, as is further indicated by the occurrence of Equisetum spores, Cyperaceae, Pseudoschizaea cysts, Polyadosporites, Glomus, and spore Types 984 and 985.
( SEE SUMMARY POLLEN DIAGRAM OF VILLAVERDE)

SILES (2º 30' W, 38º 24' N, 1320 m asl). Mountain lake, located 6 km west of the village of Siles, Jaén province, in the northern Segura mountains of southern Spain. The vegetational history covers from c. 20,300 to <505 cal yr BP. In agreement with the former studies Spain, the microfossil assemblage of Type 128 and Desmidiaceae is suggestive of comparatively poor-nutrient water stages in the context of low water temperatures. Zygnemataceae suggests meso- to eutrophic stagnant shallow water under milder climate and longer snow-free periods. Botryococcus suggests a rise of the water table to still more limnic conditions. Debarya behaves often as pioneer, but as most representatives of the Zygnemataceae, needs a relatively high water temperature to sporulate. Potamogeton and Myriophyllum develop in similar conditions to Zygnemataceae, but under less temporary water bodies. Advances of marginal vegetation are indicated by increases of Cyperaceae and Typha. Stages of seasonal desiccation associated with decomposing activity are suggested by peaks of fungal spores (Polyadosporites, Pluricellaesporites) and, especially, Pseudoschizaea cysts. The palaeolimnological sequence of Siles consists of twenty SM assemblage zones. It must be emphasized the recurrence of several intrazonal patterns. Thus, Zygnema is usually rising earlier than Spirogyra and Potamogeton, Mougeotia correlates to Zygnema peaks, Myriophyllum and Ranunculus correlate to Potamogeton peaks, Cyperaceae precedes Typha, and Asteraceae does Pseudoschizaea.
( SEE PALAEOLIMNOLOGICAL INTERPRETATION OF THE SILES SEQUENCE)
( SEE INTERPRETATION OF THE SILES PALYNO-RECORD)

GÁDOR The study site (2º 55` W, 36º 54` N, 1530 m a.s.l.) is a small lacustrine deposit (c. 400 x 350 m), 11 km northeast of the village of Berja, in the western flanks of the highest Sierra de Gádor (2250 m asl), Almería province, southeaster Spain. High amounts of Apium and Typha pollen, and Zygnemataceae spores suggest the existence of a semi-permanent body of shallow water during the zone G1. The rises of Pseudoschizaea since 5900 cal yr BP and xerophytic taxa since c. 5500 cal yr BP suggest that climate was drier during the onset of zone G2. The association of fire and dry climates is here supported by the significant positive correlations between microcharcoal, and Artemisia, xerophytes, and Pseudoschizaea, and the significant negative correlations between microcharcoal, and deciduous Quercus and other mesophytes. The coetaneous records of sordariaceous fungal spores and Riccia spores, and Polygonum aviculare pollen are probably indicative of heavy grazing in the lake catchment since c. 1700-1650 cal yr BP, prior to the grass expansion/forest decline characteristics of zone G5.
( SEE SUMMARY POLLEN DIAGRAM OF THE SITE OF GADOR)
( SEE INTERPRETATION OF THE PALAEOECOLOGICAL RECORD OF GADOR)

More in...

CARRIÓN, J.S.& NAVARRO, C. 2001. Cryptogam spores and other non-pollen microfossils as sources of palaeoecological information. Case-studies from Spain. Annales Botanici Fennici 39: 1-14

CARRIÓN, J.S. & VAN GEEL, B. 1999. Fine-resolution Upper Weichselian and Holocene palynological record from Navarrés (Valencia, Spain) and a discussion about factors of Mediterranean forest succession. Review of Palaeobotany and Palynology 106:209-236