Primary succession on the dry sea floor of the Aral Sea

Transcription

1 Primary succession on the dry sea floor of the Aral Sea Walter Wucherer University of Bielefeld, Department of Ecology

2 Contents Development of the Aralkum Desert Vegetation Districts of the Dry Sea Floor Flora of the Dry Sea Floor Succession on the loamy soils Succession on the sand soils Ecological peculiarities of the colonization Conclusions

3 Deserts of Central Asia Zaisan Emba Aral sea Syr-Darya Chu Balkhash Ili CASPIAN SEA # Bishkek # Almaty Issyk-Kul 42 Amu-Darya # Toshkent N 37 # Ashghabad # Dyushanbe 37 1: Kilometer Botanical-geografical classification of the deserts of Central Asia (Rachkovskaya et al. 2004) 81

4 Development of the Aralkum desert Water surface, km² Area of dry sea floor, km²

5 Development of the Aralkum desert What is this new desert? Which geological, geomorphological, edaphical and biological processes are affecting the present ecosystems development? Which mechanisms are governing the development of salt desert and of sand desert (barchanes)? Will there be an ecological limitation of colonisation by plants and where it will be?

6 Research activities in the region at the Aral Sea I Institute of Botany, Alma-Ata Complex research program under the leadership of the Geographical Institutes of Moskow Investigation of the negative effects of the drying process of the Aral Sea... II. III University of Kassel, DFG-Project Transect investigation at the coast of the Aral Sea University of Bielefeld, BMBF-Projects 1. Successional processes on the dry sea floor of the Aral Sea and perspective of the land use ( ) 2. Combating desertification and rehabilitation of the salt deserts in the Region at the Aral Sea ( )

7 Dry sea floor of the Aral Sea at the North Coast

8 Transect Karabulak at the North Coast of the Aral Sea

9 Floristic and vegetation districts I. Chenopodiaceae + Fabaceae + Poaceae II. Chenopodiaceae + Brassicaceae III. Chenopodiaceae + Poaceae + Polygonaceae IV. Chenopodiaceae + Limoniaceae + Tamaricaceae V. Chenopodiaceae VI. Chenopodiaceae + Fabaceae + Polygonaceae VII. Chenopodiaceae + Poaceae + Tamaricaceae VIII. Chenopodiaceae + Poaceae

10 Life Forms / Flora of the Dry Sea Floor % Chenopodiaceae Polygonaceae Brassicaceae Phanerophytes (shrubs) Chamaephytes (subshrubs) Hemicryptophytes Summer non-succulent Therophytes Summer Succulent Therophytes Spring Therophytes Plant life form spectrum of three dominant plant families of the dry seafloor of the Aral Sea Family Genera Species Species, % Chenopodiaceae Polygonaceae Brassicaceae Asteraceae Poaceae Fabaceae Boraginaceae Tamaricaceae Cyperaceae Zygophyllaceae Other families Floristic data on the vascular plants of the dry seafloor of the Aral Sea: the dominant 10 plant families and percentage of total flora

11 Succession on loamy soils Dominant Species Soil Types Stage Salicornia europaea Suaeda crassifolia Tripolium vulgare Marsh solonchak 1-2 I Climacoptera aralensis Petrosimonia triandra Bassia hyssopifolia Salt desert Coastal solonchak 3-10 II Climacoptera aralensis Climacoptera ferganica Halocnemum strobilaceum Salt desert Coastal solonchak Degraded solonchak III Halocnemum strobilaceum Haloxylon aphyllum Climacoptera ferganica Salt desert Degraded solonchak Takyr solonchak Salt shore IV Anabasis salsa Limonium suffruticosum Artemisia terrae-albae Xerosoils (burozems) >40 V

12 Stage I - Salicornia europaea plant community

13 Stage I - Salicornia europaea plant community

14 Stage II Bassia hyssopifolia plant community

15 Stage IV Halocnemum strobilaceum plant community

16 Stage II-IV Salt desert on the dry sea floor of the Aral Sea

17 Succession on loamy soils Cover, % Number of the plots former coast line recent coast line Dynamics of the cover of Salicornia europaea population (transect Bayan) Local succession (14 years)

18 Vegetation map of the transect Bayan (east coast of the Aral Sea)

19 Succession on sandy soils Dominant Species Soil Type gw: ground water (m) Stage Salicornia europaea Suaeda acuminata Atriplex fominii Marsh solonchak gw: I Atriplex fominii Horaninovia ulicina Salt deserts with barkhanes Coastal solonchak Degraded solonchak gw: II Horaninovia ulicina Haloxylon aphillum Stipagrostis pennata Barkhan deserts Degraded coastal solonchak gw: III Corispermum - species Stipagrostis pennata Calligonum - species Astragalus brachypus Barkhan deserts Sandy soils gw: IV Haloxylon persicum Calligonum - species Carex physodes Arenosoils gw: >3 >40 V Stabilization

20 Stage II Horaninovia ulicina-atriplex fominii plant community

21 Stage III Haloxylon aphyllum-atriplex fominii plant community

22 Stage IV Stipagrostis pennata-haloxylon aphyllum plant community

23 Succession on sandy soils ,0 Number of species Vegetation cover (%) 10,0 1,0 0, Time after the drying out (years) 0, Time after the drying out (years) Total number of species Number of therophites Number of perennials Stipagrostis pennata Calligonum - species Agriophyllum squarrosum Salsola paulsenii Change of the number species Dynamics of the cover of several psammophyte species

24 Ecological peculiarities of the plant colonisation of the dry seafloor The coast of the Aral Sea as a floristical centre Expansion of plant species Development of unique plant communities and ecosystems Development of monotonous widespred vegetation units Development of unexpected plant combinations Development of new ecological attributes by the plant species Contrasting fluctuating dynamics

25 Establishment of Haloxylon aphyllum on the dead rest of Phragmites australis

26 Halostachys caspica-petrosimonia brachiata plant community

27 Conclusions The dry sea floor (Aralkum desert) is the largest area worldwide where a primary succession takes place. It has continued for 40 years The flora of the dry seafloor is an immigration-flora that developed since It consists of 34 plant families, with 134 genera and 300 species The dry seafloor and the coastline of the Aral Sea is one of the diversity centers for Chenopodiaceae and Polygonaceae (Calligonum) in Central Asia The typical pattern of landscapes, of vegetation types and soils of the dry seafloor is arranged along stripes

28 Conclusions The succession on the dry sea floor is a complex process, interrelated with exogenesis, endoexogenesis and syngenesis Hundreds of species became the opportunity to fill out or to expand their distributional area. Unique compositions by various plant species have developed The ecological situation on the dry seafloor is very changeable and the dry seafloor is a big dynamic ecosystem. It is a huge experiment, a laboratory of nature with thousands of local events