Late Holocene vegetation in the Azraq Wetland Reserve, Jordan

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Author's personal copy Quaternary Research 76 (2011) 345–351

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Short Paper

Late Holocene vegetation in the Azraq Wetland Reserve, Jordan Wallace B. Woolfenden a,⁎, Linah Ababneh b a b

120 Wilson Road, Swall Meadows, CA 93514, USA P.O. Box 864, Bishop, CA 93514, USA

a r t i c l e

i n f o

Article history: Received 12 December 2010 Available online 16 September 2011 Keywords: Vegetation dynamics Pollen analysis Wetlands Azraq Wetland Reserve, Jordan

a b s t r a c t Shifts in aquatic and terrestrial vegetation associations and hydrology during the past N 3100 yr are indicated by the pollen and sediment sequences in a core retrieved from the Azraq wetland, Jordan. The pollen sequence provides evidence for a relatively stable wetland during the period of study until ca. AD 1400 when the wetland apparently declined as desert shrubland expanded. Springs continually supplied fresh water that maintained the shallow pools and marsh. In periods of increased winter precipitation, runoff from the surrounding wadis may have inundated the wetland and deposited silts and clays. During dryer episodes the influx of winter storm water would have been much less but the springs would have still provided water to the wetland and deposited peat. This is shown by the sequences of clay, silty and sandy clay loam, and peat in the core. © 2011 University of Washington. Published by Elsevier Inc. All rights reserved.

Introduction Detailed records of Holocene vegetation are scant in the southern Levant (Enzel et al., 2003) and especially from the Jordanian Plateau and desert because lakes and wetlands are sparse and unevenly distributed. Several late Holocene pollen records are available from Hula Lake, Birkat Ram, Lake Kinnert and the Dead Sea in the southern Levant (Baruch, 1986; Baruch and Bottema, 1999; Schwab et al., 2004; Neumann et al., 2007, 2010). Pollen records from Jordan have been compiled from archeological sites, various alluvial, colluvial, and lacustrine deposits, surface samples and hirax middens (Cordova, 2009). The formerly extensive Azraq wetland in eastern Jordan is suitable for a paleoecological record because of its biogeographical setting as an isolated desert oasis with a continuous water supply and exceptional biodiversity. The present study involves the analysis of a sediment core recovered from the Azraq wetland. The Azraq Basin and Wetland The Azraq Basin is a large depression in the northeastern desert of the Hashemite Kingdom of Jordan on the east slope of the Jordanian Plateau, about 100 km east of Amman (Fig. 1). A flat-bottomed playa, namely the Qa c (playa) al-Azraq, is at the center of the basin at an elevation of 506 m (Besançon et al., 1989) (Fig. 2). The Qa c al-Azraq is usually flooded following winter storms by wadis draining towards

⁎ Corresponding author. E-mail address: [email protected] (W.B. Woolfenden).

the center of the basin. These storms form a temporary fresh to brackish lake 2–3 m deep with broad muddy margins (Besançon et al., 1989). Adjacent to the qa c is the Azraq wetland (Fig. 2), a complex of spring-fed marshes and fresh water pools, formerly about 2900 m long west to east and 2000 m wide north to south. The wetland was historically sustained by a large basalt aquifer underlying the basin and recharged by runoff from the Jebel Druze, 80 km to the north in southern Syria, and from ground water from the west. Most of the wetland and qa c, which have a unique biodiversity, is included in the Azraq Wetland Reserve, administered by The Royal Society for the Conservation of Nature (http://www.rscn.org.jo/). The modern climate is arid with a mean annual precipitation of about 80 mm for the basin and 56 mm at the village of Azraq Janubi (FAO, 2010). The basin has dry warm summers with rains during the cool winters from the Cyprus Low of the eastern Mediterranean Sea (Cordova, 2007). Interannual rainfall variability is high and half of the annual precipitation can fall in one day. The annual maximum to minimum temperature range (1962–1990) is 36.1–2.8°C (FAO, 2010). Present day vegetation The present vegetation surrounding the qa c – classified as SaharoArabian (Al-Eisawi, 1996) – reflects the arid climate and is dominated by sparse shrubs of Chenopodiaceae associated with annual succulents and grass (Al-Eisawi, 1996). Comparatively dense vegetation with a more diverse association of species, including tamarisk (Tamarix spp.) is restricted to the wadis. Wadi Al-Butm, on the southwest side of the basin and tributary to the qa c is unique for its extensive stands of pistachio trees (Pistacia atlantica). Vegetation in

0033-5894/$ – see front matter © 2011 University of Washington. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.yqres.2011.08.007

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Figure 1. Map of Jordan showing the location of the Azraq wetland (Wahat al-Azraq) study area.

the qa c is dominated by salt-tolerant plants on silt dunes, such as the shrub Nitraria retusa (gharqad) and Tamarix passerinoides and halophytes bordering the qa c dominated by succulent chenopods such as Halopeplis amplexicaulis, Suaeda asphaltica (seablite) and Halocnemum strobilaceum, and the grass Aeluropus littoralis (AlEisawi, 1996). Fresh water vegetation of the Azraq wetland, growing in organically rich sediments termed Phragmites peat, is arrayed along a changing gradient from Typha domingensis (cattail) in the pools, Phragmites australis (reeds), Juncus sp. (rushes), Imperata cylindrical and Tamarix amplexicaulis at the edges. Sonchus maritimus, and Inula crithmoides, are also dominant plants. P. australis is the primary freshwater colonizer, followed by T. domingensis. Seasonally dry brackish water bodies support Scirpus maritimus (alkali bulrush), Chara sp. (muskgrass), Ruppia sp. (ditch-grass) and Zannichellia palustris (horned pondweed) (Al-Eisawi, 1996). Extensive irrigated agricultural land in and around the wetland contributes to the modern pollen rain (Fariz and Hatough-Bouran, 1998). Ground water pumping of the Azraq Basin aquifers for supplying Amman and Irbid, and irrigating fields in the area began in 1963 (Nelson, 1974) and escalated in the 1980s and 1990s (Fariz and Hatough-Bouran, 1998). This resulted in a drastic drop in the water table and near desiccation of the wetland by December, 1992, and the cessation and near drying of the spring pools by 1994 followed by a near-total ecosystem collapse of the wetland (Fariz and HatoughBouran, 1998). An extensive rehabilitation of the wetland, beginning in 1994, included the dredging of pools, cleaning and deepening major wadis, and reverse pumping water to the ponds although approximately less than a third of the wetland was restored (Fariz and

Hatough-Bouran, 1998). Despite the drying of the wetland and subsequent restoration work Sirhani Pool (Fig. 2), which was selected for coring, may have remained wet with no significant human disturbance (Esaid, W., Azraq Tourism Officer, personal communication, 2008). If the pool had dried, however, the 2 yr between drying and rewetting would have had a minimal impact on the surface peat and pollen. Methods In 2008, a sediment core (AZ3-08) was retrieved in water depth of 20 cm at the northeast edge of Sirhani Pond (Figs. 2 and 3) with a Livingston square-rod piston corer. Total core length is 179.5 cm with 86% recovered. Dense clays at the bottom of core prevented further sediment retrieval. The core drives were described and sampled at Yarmouk University in Irbid. The texture classes of the sediments were estimated using standard field methods (e.g., Soil Survey Division Staff, 1993). Seven radiocarbon samples were taken from peat layers. Pollen extraction was done at the Department of Geography, University of Nevada, Reno. A total of 48 1 cm³ samples were processed according to standard methods modified from Faegri and Iverson (1989). Clay sediments were either pretreated with pyrophosphate or completely treated with sodium polytungstate flotation. Of the total processed samples 23 were selected for pollen identification and tabulation at 400× or 1000× power with a binocular microscope. No pollen was present in the clay sediments. Statistical analysis and plotting was done with Tilia software (Grimm, 1992) and the Constrained Incremental Sum of Squares

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Figure 2. Satellite image of the Azraq wetland and qac. The present artificially maintained marsh and pools are clustered in the extreme western area opposite the town of Azraq Janubi (Shishan). The coring site of Sirhani Pool is indicated. From Google Earth (Imagery dates: Oct. 26, 2003–Apr. 10, 2009).

Cluster Analysis (CONISS) program (Grimm, 1987) was used to numerically resolve pollen zones. As it was critical to tabulate aquatic P. australis separately from terrestrial Poaceae species pollen all grass pollen with a diameter less than 24 μm was classified as P. australis. This identification was based on published measurements of 28 grass species indicating that P. australis pollen is the smallest of all listed pollens with no overlap with any other species known in Jordan (Bonnefille and Riollet, 1980).

Results Core description and chronology The summary description of core AZ 3-08 is given in Table 1 and AMS radiocarbon analyses of three peat samples is given in Table 2. An age-depth model was not plotted because of possible differential sedimentation rates of clay, silty and sandy clay loam, and peat.

Figure 3. Photograph of Sirhani Pool, view to south. The square rod sediment corer marks where the core was retrieved. Tamarix passerinoides and Juncus sp. grow along the shore in the background and Typha domingensis, young Phragmites australis, Sonchus maritimus, and the grass, Imperata cylindrical are in the foreground.



Table 1 Summary description of Core Az 3–08, Sirhani Pool. Unit

Depth (cm)

Description

XIV

0–18/20

XIII

18/20–44.5

XII XI

44.5–51.5 51.5–69

X

69–87

IX VIII

87–89.5 89.5–99.5

VII

99.5–109

VI

109–110

V IV III

110–132.5 132.5–137.5 137.5–144.5

II

144.5–150.5

1

150.5–179.5

Black (10 yr 2/1, wet) sticky, plastic peat. The top 2 cm is very fibrous with small roots. One large root, 0.5 mm dia. × 21 cm long, and a Phragmites australis stem sheath. One small root fragment ~ 2 mm dia. Smooth, wavy, angled boundary to: Mottled very dark gray (10 yr 3/1, wet) to dark gray (10 yr 4/1, wet) and gray (10 yr 5/1, wet), sticky, plastic to slightly sticky, plastic sandy clay loam. Roots are not present. Moderate fraction of very coarse to fine sand and pebbles. Sand is friable carbonates. Color is predominately dark gray (10 yr 4/1, wet) at 34.5–42 cm and color is predominately very dark gray (10 yr 3/1, wet) with carbonate sand fraction decreasing at 42.5–44.5 cm. Diffuse, wavy boundary to: Very dark gray (10 yr 3.1, wet) sticky, plastic sandy clay loam to silty clay. Fine roots present ~ 48 cm. Diffuse boundary to: Black (7.5 yr 2/0, wet) plastic, sticky to very sticky peat. Very small carbonate sand fraction present. Sand decreases to almost nil at 61–62 cm At 63–64 cm fibrous peat with abundant small roots and friable sand is present, which is very slightly sticky, very slightly plastic when crushed. At 66–69 cm Roots larger (N 1 mm dia.). Phragmites australis stem fragment. Sand not present after 67 cm. Diffuse boundary to: Black (7.5 yr 2/0, wet) slightly sticky, slightly plastic peat. Very small sand fraction. The peat is fibrous with abundant small roots at 69–71 cm. By 83 cm the sand fraction is gone. Diffuse boundary to: Black (10 yr 2/1, wet) sticky, plastic peat. Roots and sand absent. Diffuse boundary to: Slightly mottled and striated black (10 yr 2/1, wet) and very dark gray (10 yr 3/1, wet) very slightly sticky, slightly plastic organic sandy loam Moderate fraction of fine to coarse sand with subangular granules to small cobbles. Particles dry to black and are friable. They appear to be hardened peat. At 92 cm sand fraction decreases and the texture becomes more plastic. Few fine roots present. Texture becomes a more plastic silty clay loam from 96.5–99.5. Faint abrupt boundary to: Faint striations (2–5 mm thick) of very dark gray (10 yr 3/1, wet) and dark gray (10 yr 4/1, wet) slightly sticky, slightly plastic to plastic silty clay loam. There is a tendency down core toward very dark grayish brown (10 yr 3/2, wet) to dark grayish brown (10 yr 4/2). Fine to medium (≤1 mm) roots become more frequent at about 101 cm. At about 104.5 cm the colors become mottled (mottles ~ 5 mm dia.) with the addition of black (10 yr 2/1, wet). At about 107 cm the color becomes more uniformly banded between very dark gray and black. Abrupt boundary to: Very dark gray (10 yr 3/1, wet) sticky, slightly plastic to plastic sandy clay loam to loamy sand. Large fraction of very coarse to medium coarse carbonate sand present. Abrupt boundary to: Dark gray (N4/, wet) very sticky, very plastic gleyed clay. Abrupt boundary to: Black (7.5 yr 2/0, wet) sticky, plastic peat. Few fine to medium roots (≤1 mm). Diffuse, wavy and irregular boundary to: Black (10 yr 2/1, wet) slightly sticky, slightly plastic to plastic peaty silty clay loam. Roots are gone by ~ 140.5 cm. [Note: there is a clay smear a t 136–141.5 cm (1.5 cm wide × 5.5 cm long), and wedged into the core to 1 cm deep.] Diffuse, wavy boundary to: Mottled black (10 yr 2/1, wet) very dark gray (10 yr 3/1, wet) and dark gray (10 yr 4.1, wet) silty clay loam. Few small roots, some clay mottles 0.5 × 15 cm. A few sand grains at boundary. Abrupt, wavy- irregular boundary to: Dark greenish gray (5G 4/1, wet) very sticky, very plastic gleyed clay. There is a thick smear of silty sediments on the sides of the core at this depth.

In general, a dark greenish clay layer of unknown depth at the core bottom is followed by a 13 cm layer of silty clay loam and by a 5 cm peat stratum that ends at ca. 1370 BC. A second, 22.5 cm, dark gray clay layer after this date is overlain by a 1 cm layer of carbonate sands and then by a 19.5 cm sequence of silty clay loam to sandy loam followed by a relatively long 38 cm peat layer with a top age of ca. AD 600. Next, a 32 cm silty clay to sandy clay loam layer is succeeded at ca. AD 1430 by fibrous peat at the surface. The silty to sandy clay loams also contain carbonate sand.

the qa c and wetland during winter rainfall supplements the predominant pollen airfall. Pollen was not present in the clay strata; thus, the bottom clay was excluded in the pollen diagram. The only macrofossils in the cores are stem fragments of mature Phragmites ausralis in the top peat and at a depth of 66–69 cm, although only small reeds are growing around the pool at present. The pollen diagram is given in Figure 4 and the pollen zones are described as follows. Zone 1A (149–132 cm)

Pollen sequence Preservation of most of the pollen ranges from good to fair and frequencies were sufficient for 302 or more pollen grain tabulations. However, six samples show either fair to poor preservation or sparse numbers of pollen grains, or both. Four samples contain pollen frequencies low enough that, for practical purposes, total pollen counts were restricted to 205 or less pollen grains. Poorly preserved and sparse pollen are found in all the polliniferous sediment types. Abundant micro-charcoal is present in all but the top peat deposits and in one sandy clay loam sample at 91–90 cm, immediately below peat. The flat topography and large area of Azraq Basin simplifies and expands the source area for the pollen rain, although local pollen is probably over-represented because the area of the wetland is large. Transportation of pollen by wadi systems that deliver flood waters to Table 2 AMS radiocarbon dates from Sirhani Pool (core AZ3-08). Depth (cm)

Lab number

Age (14C yr BP)

2σ Calibrated age (cal yr BP)

2σ Calibrated age (cal yr BC/AD)

16.0–17.0 51.5–52.5 132.5–133.5

Beta-270405 Beta-270404 Beta-270403

500 ± 40 1440 ± 40 3110 ± 40

550–500 1400–1290 3400–3250

AD 1400–1450 AD 550–660 1450–1300 BC

Note. The BETA Analytic, Inc. calibration of radiocarbon dates used the INTCAL04 database (Reimer et al., 2004).

Phragmites pollen is a relatively high ~ 38% in the dark silty clay loam and increases to 45% in the peat. Chenopodeaceae (~ 9.5%), Artemesia (6–4%), and Tamarix (3–0.8%) pollen are also relatively frequent in the silty clay loam but decrease to 3%, 0.9% and 0.1%, respectively, in the peat deposit. Typha is a minor aquatic element and increases to 5% in the peat, and Cyperaceae is absent in the zone. Zone 1B (107–90 cm) Zones 1A and 1B are separated by a hiatus in the pollen sequence in a clay stratum. The two zones are more similar to each other relative to the other pollen zones. Phragmites pollen begins with a frequency of 30% and increases to 39% while Chenopodeaceae, Artemesia, and Tamarix have peak frequencies of 16%, 9.5%, and 7% and drop to 3%, and 4% at the top of the zone. The frequencies of Artemesia and Tamarix, and also Quercus (2%) are the highest in the pollen sequence. Typha and Cyperaceae remain low and absent, and the aquatic Zannichellia palustrus-type (horned pondweed) appears only once in the core at 3%. Zone 2 (83–48 cm) This zone encompasses most of the longest peat deposit in the stratigraphy. There is a continued increase of Phragmites pollen from

Figure 4. Pollen percentage diagram for AZ3-08 during the past N3100 yr. The shaded curves are an ×5 exaggeration of the pollen percentages that are plotted in black. No pollen is present in the clay stratum. The clay at a depth from 150.5 cm to the bottom of the core at 179.5 cm also contains no pollen and is not included in the diagram. Pollen zones were calculated from a Constrained Incremental Sum of Squares Cluster Analysis (CONISS) program (Grimm, 1987).

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the previous zones attaining the highest frequencies in the pollen sequence at ~ 46%. The other major aquatics begin to reach higher percentages: Cyperaceae (probably Scirpus maritimus) appears for the first time in this zone, reaching 2% and Typha has a peak early in the zone at 14%. Chenopodeaceae pollen maintains frequencies similar to the previous zones but fluctuates between a high of 19% at 53–52 cm and the lowest percentage in the pollen sequence at 0.2% (68–67 cm). This low Chenopodeaceae percentage coincides with a peak in Phragmites and Tamarix. Liguliflorae pollen (probably Sonchus maritimus) rises to 10% from previously low frequencies of less than a percent at 61–60 cm. Populus pollen has a single peak at 2%; otherwise, it is absent in the rest of the zone. Artemisia is at its lowest abundance (b1%) and is also absent from the record in the middle of the zone. Zone 3 (41–16 cm) Phragmites pollen decreases to 21% while Cyperaceae and Typha percentages increase with fluctuations to coinciding peaks of 6–8% and 17–29%, respectively. The second peaks are within the base of the top peat deposit. Chenopodeaceae frequencies are fairly stable between 11% and 8% and Tamarix frequencies vary between 1% and 6%. Populus pollen peaks twice at ~4%. Liguliflorae continues at relatively moderate frequencies (4–8%) from Zone 2. Pinus pollen reaches its highest percentage in the record at N1%. Zone 4 (13–0 cm) According to the CONNIS analysis this zone is more numerically dissimilar than Zones 1A to 3. It is entirely within the top peat deposit. Phragmites pollen decreases to a low of 10% in the upper centimeter of the core. Chenopodeaceae increases to its highest frequencies in the pollen sequence, from 28% to a maximum of 47.5% at the surface of the peat. Artemisia increases to 4%. Liguliflorae varies between 1% and 4.0% and Plantago major-type is at its highest frequencies in the core from 4% to 9% at the peat surface. Tamarix fluctuates between 1% and 4.5%. Cyperaceae decreases from its peak in Zone 3 to 0.5% and 1% at the peat surface, and Typha also decreases from its high peak in Zone 3 to 6% but then increases to over 12%. Discussion and conclusions The pollen assemblages show a variation in relative frequencies among local aquatic types and surrounding Saharo-Arabian desert types that indicate changes in relative species abundance within the vegetation associations. There are, however, no changes in the pollen assemblages during the past N3100 yr that would indicate a replacement of the Saharo-Arabian vegetation type with another type such as the Irano-Turanian shrub-steppe (Al-Eisawi, 1996). A modern surface sample from the Azraq wetland is similar to the surface peat sample, characterized by a high proportion of Phragmites pollen (Cordova, 2009). Major trends in the pollen sequence are (a) a dominance of Phragmites within the second peat layer (Units IX–XI) (b) a decrease in Phragmites and in Cyperaceae and Typha beginning at a depth of ca. 41 cm, (c) an increase in Liguliflorae beginning ca. 60 cm, (d) very low frequency in Artemisia between ca. 82 cm and ca. 15 cm and relatively high frequencies between ca. 149 cm and ca. 90 cm, (e) and dominance of Chenopodeaceae and Plantago major-type from about 12 cm to the surface (after AD 1400–1450 according to the radiocarbon date on the top peat). Except for pollen from the desert trees of Tamarix and Populus, tree pollen such as Quercus, Olea and Pinus was probably carried from the western mountain ranges by prevailing winds. Olea in the surface peat sample may also have originated from nearby cultivated olive orchards. The opposing frequencies of Phragmites

to Typha and Cyperaceae may signify fluctuations between Typhadominated fresh water pools and Phragmites habitat, and fluctuations in the extent of brackish water. The total aquatic pollen sequence provides evidence for a relatively stable wetland during the period of study until ca. AD 1400 (ca. 16 cm) when the wetland apparently declined as desert shrubland expanded. This expansion is indicated by a relatively large increase in Chenopodeaceae and perhaps by an increase in Artemisia and Plantago major pollen. Artemisia herba-alba is a dominant element of the shrubsteppe vegetation (Irano-Turanian region) to the west of the desert at the present time (Al-Eisawi, 1996). Therefore, an increase in Artemisia pollen could indicate (a) an eastern expansion of the shrub-steppe, (b) more local storms and floods, (c) an increase in wind from the west. Carefully, we suggest that all these three options are directly related to an increase in average rainfall and runoff. Desiccation of the wetland by modern groundwater pumping may account, in part, for the pollen assemblage in the top first centimeter of the peat. Two years of wetland drying (see above), however, would not likely be visible in the pollen record given that the pollen assemblages in the entire peat deposit (Unit XV) for the past ca. 500 yr indicates a relatively dry environment. There are apparently three sequences of sedimentary environments shown in the core, each sequence consisting of clay, silty and sandy clay loam, and peat. The top third sequence has silty clay strata. The sedimentary environments may have been sustained and enhanced by episodes of the two sources of water to the wetland which occur annually (Besançon et al., 1989). Recent observations before groundwater pumping show that springs continually supplied fresh water at a relatively high rate that have maintained the shallow pools and marsh. Winter runoff from the wadis has a heavy bedload of sandy-silty sediments, which is deposited on the surface of the qa c. In the past, clays have also been deposited in the qa c (Besançon et al., 1989, Fig. 9). All the sediments in the core indicate that they were deposited in low water flow velocity in accordance with the shallow (ca. 3 m) gradient from about 509 m on the periphery of the qa c (including Sirhani Pool) to ca. 506 m at the center (Besançon et al., 1989). In periods of increased precipitation, water may have inundated the wetland and deposited silts and clays. During dryer episodes the influx of winter storm water onto the qa c would have been much less but the springs would have still provided water to the wetland. In both cases wetland vegetation would have been sustained, only the sediments would have varied. This hydrological variation may reflect changing climate regimes at comparable scales. Acknowledgments This study was primarily funded by a Fulbright scholarship awarded in 2008. We thank Ahmad Abu-Siniyeh and Marwan Husni Ga'gaa' for field assistance; and Dawud Al-Eisawi, Omar Al-Shoshan, Carlos E. Cordova, Caroline Davies, Jamil Lahham, Hanan I. Malkawi, Enas Sakkijha, Wesam Talal Esaid, Alain McNamara and the staff of the Jordanian-American Fulbright Commission, and the American Center for Oriental Research for assistance and advice that helped facilitate the research. Two anonymous reviewers greatly improved the manuscript. References Al-Eisawi, D., 1996. Vegetation of Jordan. UNESCO Regional Office for Science and Technology for the Arab States, Cairo. Baruch, U., 1986. The late Holocene vegetational history of Lake Kinneret (Sea of Galilee), Israel. Paléorient 12 (2), 37–48. Baruch, U., Bottema, S., 1999. A new pollen diagram from Lake Hula: vegetational, climatic, and anthropogenic implications. In: Kawanabe, H., Coulter, G.W., Anna, C.,

Author's personal copy W.B. Woolfenden, L. Ababneh / Quaternary Research 76 (2011) 345–351 Roosevelt, A.C. (Eds.), Ancient Lakes: Their Cultural and Biological Diversity. Kenobi Productions, Ghent, Belgium, pp. 75–86. Besançon, B., Geyer, B., Sanlaville, P., 1989. Contribution to the study of the geomorphology of the Azraq Basin, Jordan. In: Copeland, L., Hours, F. (Eds.), The Hammer on the Rock, Studies in the Early Paleolithic of Azraq, Jordan: Maison de L'Orient Méditerranéen C.N.R.S.-Université Lumière-Lyon 2 Lyon (France), Oxford Press Archaeological Series No. 5, B.A.R. S540, pp. 31–64. Bonnefille, R., Riollet, G., 1980. Pollens des savanes d'Afrigne Orientale. Editions du Centre National de la Recherche Scientifique, Paris, p. 140. Cordova, C.E., 2007. Millennial Landscape Change in Jordan. The University of Arizona Press, Tucson. Cordova, C.E., 2009. Palynology of anthropicized landscapes in Jordan: a survey of modern and fossil records of Quercus, Pistacia, and Olea pollen. In: Dean, R.M. (Ed.), Center for Archaeological Investigations, Occasional Paper No. 37. Southern Illinois University, pp. 1–26. Enzel, Y., Bookman (Ken Tor), R., Sharon, D., Gvirtzman, H., Dayan, U., Ziv, B., Stein, M., 2003. Late Holocene climates of the Near East deduced from Dead Sea level variations and modern regional winter rainfall. Quaternary Research 60, 263–273. Faegri, K., Iverson, J., 1989. Textbook of Pollen Analysis, 4th Edition. Wiley, Chichester. FAO (Food and Agriculture Organization of the United Nations), 2010. FAOClim-NET http//geonetwork3.fao.org/2010. Fariz, G.H., Hatough-Bouran, A., 1998. Case study: Jordan. Population dynamics in arid regions: the experience of the Azraq Oasis Conservation Project. In: de Sherbinin, A., Dompka, V. (Eds.), Water and Population Dynamics: Case Studies and Policy Implications. American Association of the Advancement of Science, Washington D.C., pp. 75–86.

351

Grimm, E.C., 1987. CONISS: a FORTRAN 77 program for stratigraphically constrained cluster analysis by the method of incremental sum of squares. Computers and Geosciences 13, 13–35. Grimm, E.C., 1992. Tilia and Tilia-graph: pollen spreadsheet and graphics programs. Programs and Abstracts, 8th International Palynological Congress, Aix-en-Provence, September 6–12, p. 56. Nelson, B., 1974. Azraq: Desert Oasis. Ohio University Press. Neumann, F.H., Kagan, Elisa J., Schwab, M.J., Stein, M., 2007. Palynology, sedimentology and palaeoecology of the late Holocene Dead Sea. Quaternary Science Reviews 26, 1476–1498. Neumann, F.H., Kagan, E.J., Leroy, S.A.G., Baruch, U., 2010. Vegetation history and climate fluctuations on a transect along the Dead Sea west shore and their impact on past societies over the last 3500 years. Journal of Arid Environments 74, 756–764. Reimer, P.J., Baillie, M.G.L., Bard, E., Bayliss, A., Beck, J.W., Bertrand, C., Blackwell, P.G., Buck, C.E., Burr, G., Cutler, K.B., Damon, P.E., Edwards, R.L., Fairbanks, R.G., Friedrich, M., Guilderson, T.P., Hogg, A.G., Hughen, K.A., Kromer, B., McCormac, F.G., Manning, S., Bronk Ramsey, C., Reimer, R.W., Remmele, S., Southon, J.R., Stuiver, M., Talamo, S., Taylor, F.W., van der Plicht, J., Weyhenmeyer, C., 2004. IntCal04 Terrestrial radiocarbon age calibration, 0–26 cal kyr BP. Radiocarbon 46, 1029–1058. Schwab, M.J., Neumann, F., Litt, T., Negendank, J.F.W., Stein, M., 2004. Holocene palaeoecology of the Golan Heights (Near East): investigation of lacustrine sediments from Birkat Ram crater lake. Quaternary Science Reviews 23, 1723–1731. Soil Survey Division Staff, 1993. Soil survey manual. Soil conservation service. U.S. Department of Agriculture Handbook, 18.