Application and limitations of the Artemisia/Chenopodiaceae pollen ratio in arid and semi-arid China

The Holocene ◽  
2012 ◽  
Vol 22 (12) ◽  
pp. 1385-1392 ◽  
Author(s):  
Yan Zhao ◽  
Hongyan Liu ◽  
Furong Li ◽  
Xiaozhong Huang ◽  
Jinghui Sun ◽  
...  
Keyword(s):  
Arid Regions ◽  
Positive Relationship ◽  
Vegetation Types ◽  
Pollen Data ◽  
Data Synthesis ◽  
Modern Pollen ◽  
Vegetation Zones ◽  
Desert Areas ◽  
Vegetation And Climate ◽  
Semi Arid

The Artemisia/Chenopodiaceae (A/C) ratio is assumed to be a useful index for reconstructing moisture changes in arid and semi-arid regions. Thorough modern pollen studies are still lacking to understand the reliability and limitation of A/C ratio as a moisture indicator, however. Here we review how well this ratio can be applied in arid and semi-arid China on the basis of new surface pollen data, previous data synthesis and other publications. Results indicate that variance in the A/C ratio can permit identification of modern vegetation types and that the A/C ratio generally has a positive relationship with annual precipitation. However, soil salinity, vegetation community composition, human activity and sample provenance (e.g. soil and lake sediments) will affect the values of the A/C ratio in different vegetation zones and therefore the A/C ratio is not comparable in different regions. We argue that the A/C ratio can only be used to reconstruct vegetation types and climate change in regions with precipitation <450–500 mm, and in steppe, steppe desert and desert areas. Careful studies should be undertaken to understand the modern pollen–vegetation–climate relationships in various regions before using the A/C ratio to interpret vegetation and climate.

scholarly journals Relación lluvia de polen-vetación en selvas de Quintana Roo

2017 ◽  
pp. 31 ◽  
Author(s):  
Gerald A. Islebe ◽  
Rogel Villanueva-Gutiérrez ◽  
Odilón Sánchez-Sánchez
Keyword(s):  
Zea Mays ◽  
Quintana Roo ◽  
Vegetation Types ◽  
Pollen Data ◽  
Indicator Taxa ◽  
Modern Pollen ◽  
Pollen Content ◽  
Ordination Techniques ◽  
Ordination Analysis ◽  
Pollen Rain

Modern pollen rain was studied along a 450 km long transect between Cancun-La Unión (Belizean border). Ten moss samples were collected in different vegetation types and analyzed for pollen content. The data were analyzed with classification (TWINSPAN), ordination analysis (DCA) and different association indices. Classification and ordination techniques allowed us to recognize three different pollen signals from semievergreen forest (with Maclura, Apocynaceae, Moraceae, Sapotaceae, Araceae, Cecropia, Celtis, Eugenia and Bursera), acahual (with con Coccoloba, Metopium, Anacardiaceae, Urticales, Melothria, Croton, Palmae) and disturbed vegetation (with Zea mays, Mimosa and Asteraceae ) . The degree of over-representation and underrepresentation of the pollen data with respect to the modem vegetation was established, being under-represented mostly entomophilous species. We can conclude that the actual pollen signal can be used for calibrating paleosignals, if clear groups of indicator taxa can be established.

Vegetation and Climate Interactions in Semi-Arid Regions

1993 ◽  
Vol 46 (4) ◽  
pp. 373
Author(s):  
David L. Scarnecchia ◽  
A. Henderson-Sellers ◽  
A. J. Pitman
Keyword(s):  
Arid Regions ◽  
Climate Interactions ◽  
Vegetation And Climate ◽  
Semi Arid

scholarly journals Pollen-based vegetation and climate reconstruction of the Ferdynandovian sequence from Łuków (eastern Poland)

2013 ◽  
Vol 53 (1) ◽  
pp. 115-138 ◽  
Author(s):  
Irena Agnieszka Pidek
Keyword(s):  
Plant Communities ◽  
Air Temperature ◽  
Climate Changes ◽  
Vegetation History ◽  
Middle Pleistocene ◽  
Pollen Data ◽  
Modern Pollen ◽  
Climate Indicators ◽  
Oceanic Climate ◽  
Vegetation And Climate

ABSTRACT Early middle Pleistocene deposits from Łukow, correlated with the Cromerian complex, represent rare bi-partite Ferdynandovian pollen sequence encompassing two interglacial warmings (F1 and F2) separated by F1/2 cooling/glaciation and related to MIS 15-13. The paper presents pollen-based palaeoecological and palaeoclimate investigations in which plant climate indicators were applied. Additionally modern pollen dataset from the Roztocze region was used to evaluate vegetation history in terms of forest communities and presence and abundance of tree taxa sensitive to air temperature and humidity. Climate changes derived from pollen data indicate strong oceanic features of the climate of the first interglacial (F1) resembling those typical for the beginning of the Eemian, followed by cooling (F 1/2) with plant communities typical of the Pleistocene steppetundra, which undoubtedly indicate strong continentality, and subsequent return of more oceanic climate (F2) with mean remperature of the warmest month exceeding 18°C. Both pollen succession and climate changes recorded in the Łukow sediments correlate well with other bi-partite successions known from eastern part of European Lowlands.

BIODIVERSITY OF HALOPHYTES IN SEMI-ARID REGIONS CASE OF ZAHREZ GHARBI AND ZAHREZ CHERGUI (ZAAFRANE-DJELFA) IN ALGERIA

2020 ◽  
Vol 76 (11) ◽  
Author(s):  
Senni Rachida ◽  
De Belair Gerard ◽  
Abdelkrim Hacene
Keyword(s):  
Arid Regions ◽  
Semi Arid

Water Resources Management in the Semi-Arid Central Valley of California

1987 ◽  
Vol 19 (9) ◽  
pp. 97-106
Author(s):  
J. J. Vasconcelos
Keyword(s):  
Resource Management ◽  
Ground Water ◽  
Water Resource ◽  
Water Resource Management ◽  
Arid Regions ◽  
Central Valley ◽  
The United States ◽  
Policy Makers ◽  
Ground Water Resource ◽  
Semi Arid

Hater resource managers in semi-arid regions are faced with some unique problems. The wide variations in precipitation and stream flows in semi-arid regions increase man's dependence on the ground water resource for an ample and reliable supply of water. Proper management of the ground water resource is absolutely essential to the economic well being of semi-arid regions. Historians have discovered the remains of vanished advanced civilizations based on irrigated agriculture which were ignorant of the importance of proper ground water resource management. In the United States a great deal of effort is presently being expended in the study and control of toxic discharges to the ground water resource. What many public policy makers fail to understand is that the potential loss to society resulting from the mineralization of the ground water resource is potentially much greater than the loss caused by toxic wastes discharges, particularly in developing countries. Appropriations for ground water resource management studies in developed countries such as the United States are presently much less than those for toxic wastes management and should be increased. It is the reponsibility of the water resource professional to emphasize to public policy makers the importance of ground water resource management. Applications of ground water resource management models in the semi-arid Central Valley of California are presented. The results demonstrate the need for proper ground water resource management practices in semi-arid regions and the use of ground water management models as a valuable tool for the water resource manager.

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