As a great yurt are the heavens

Covering the steppe in all directions

Blue, blue is the sky

Vast, vast is the steppe

Here the grass bends with the breeze

Here are the cattle and sheep

- Mongol Poem

Giourga, H. , N. S. Margaris and D. Vokou. 1998. Effects of Grazing

Pressure on Succession Process and Productivity of Old Fields on

Mediterranean Islands. Environmental Management 22:4:589-596.

This study looked at successional recovery of natural vegetation on lands

historically cultivated but later abandoned. The abandoned sites on 5

Mediterranean islands were used for grazing by sheep and goats.

Abandonment ranged from 5 to 40 years before the study. Vegetation

succession after cultivation was compared to succession following a fire,

which may have some valid similarities. Annuals are among the first

colonizers and decline as woody species eventually move into a disturbed

site. However, the researchers found that grazing was severely affecting

recovery of the vegetation and biomass production. In addition, the

nonrecovering vegetation and decreasing biomass production could not

adequately support the grazing animals. This study demonstrates the

effects of grazing animals on vegetation patterns, although it is somewhat

artificial because populations are controlled by humans rather than

natural equilibrium.

Petuch, E. J. 1995. Molluscan Diversity in the Late Neogene of Florida:

Evidence for a Two-Staged Mass Extinction. Science 270:275.

This paper uses recent data to challenge two earlier and opposing

conclusions: 1) that Floridian molluscan diversity decreased during the

Pliocene-Pleistocene mass extinction, but somewhat rebounded later; and 2)

that, although Floridian fauna experienced extinctions over the

Pliocene-Pleistocene periods, invasion and speciation balanced maintained

overall diversity. Relying on analysis of eight gastropod families

(representing different trophic levels) appearing in beds from 3 mya

through the late Pleistocene, the author concludes that species diversity

declined, rebounded, then declined dramatically at the end of the studied

period. Six of the families show a much lower species diversity in Recent

Florida. Some of the families demonstrated a loss of species diversity by

a factor greater than eight. The broad, two-staged molluscan mass

extinction may indicate complete ecosystem collapse.

Williams, D. M. 1996. The Barbed Walls of China: A Contemporary

Grassland Drama. The Journal of Asian Studies 55, no. 3: 665-691.

Nomadic Mongols have lived for thousands of years on the steppes of

Northern China. Pressures on traditional Mongol culture include the

invasion of grasslands by Chinese for farming and natural loss of land to

desertification. Chinese policy has been to change open range grazing

land (steppe grasslands) to commercial livestock lands run by Chinese farm

collectives. Parcelization of lands has created hardships for Mongol

people as well as significant ecosystem degradation. The Han Chinese

outlook on steppe grasslands can be compared to the American outlook of

grasslands. Land should be privatized and parceled. The result has been

predictable but with an interesting twist. Settled Mongols have been

given land. Those Mongols wealthy enough to have fencing often choose not

to graze this land, preferring to use open grazing land for their cattle

and saving their private land for personal hay reserves. The open

grasslands that were thought to be protected by land privatization have

become overgrazed and degraded while small patches of steppe grasslands

thrive in fenced areas. Another unforeseen side affect on Mongol culture

has been that the changing landscape mosaic has caused confusion for

traditional herdsman who are unsure of how to read the new landscape. The

frustration has resulted in herdsman giving up traditional grazing methods

that allowed a sustainable grassland ecology for a more lackadaisical

approach that further degrades the steppe grassland.

van Jaarveld, A.S., S. Freitag, S. Chown, C. Muller, S. Koch, H. Hull, C.

Bellamy, M. Kruger, S. Endrody, M. Mansell, and C. Scholtz. Biodiversity

Assessment and Conservation Strategies. Science 279:2106-2109.

This article was short but nearly unintelligible. The gist of the article

is that methods of assessing vegetation diversity and community diversity

need to be reassessed.

Zimov, S.A., S.P. Davidov, Y.V. Voropaev, S.F. Prosiannikov, I.P.

Semiletov, M.C. Chapin, and F.S. Chapin. 1996. Siberian CO2 Efflux in

Winter as a CO2 Source and Cause of Seasonality in Atmospheric CO2.

Climatic Change 33:111-120.

Seasonal fluctuations of atmospheric CO2 concentrations are approximately

twice the expected values in northern latitudes. Although there is a

large carbon sink between 30 and 60 lattitudes, there appears to be a net

efflux of CO2 in lattitudes above 60, especially above the

permafrost-dominated Arctic. The tundra region of this study is

characterized by a mosaic of wet tundra, shrub tundra, forest tundra, and

boreal larch forest. The study observed soil and vegetation CO2

fluctuations over a three year period. Of a variety of tundra vegetation

mosaics, grass-dominated sites were the only sites to actually have a net

influx of CO2. The scientists next extrapolated their results to a larger

scale to determine whether the observations could potentially account for

the CO2 efflux. Assuming that 8% of the earths surface and atmospheric

CO2 pool is above 66 N, their results could potentially account for 3-42%

of the observed annual fluctuations. Northern soils have accumulated

carbon since the Pleistocene due to permafrost characteristics of low

temperature and saturated soils. The change from carbon accumulating to

carbon outputting may be from a warming of permafrost soils from global

warming or lass of thermally-insulating moss and lichen cover.

Zimov, S.A., G.M. Zimova, S.P. Daviodov, A.I. Daviodova, Y.V. Voropaev,

Z.V. Voropaeva, S.F. Prosiannidov, I.V. Semiletova, and I.P. Semiletov.

1993. Winter Biotic Activity and Production of CO2 in Siberian Soils: A

Factor in the Greenhouse Effect . Journal of Geophysical Research

98:5017-5023.

This paper correlates local atmospheric concentrations of CO2 with

subsurface concentrations of CO2 in permafrost near latitude 70oN in

Siberia. Variations in the concentrations were found to be synchronous

and seasonal. Formation of a dry layer (DL) beneath the frozen upper

layer during October promotes activity of aerobic organisms, increasing

production of CO2 at the same time that consumption of CO2 through

photosynthesis is reduced. Lower temperatures in January freeze the

available water in the DL, inhibiting aerobic activity and reducing

production of CO2 . Porosity of the frozen layer above the DL permits

exchange of gases with the atmosphere. Annual increases of global

atmospheric CO2 coincide with the active period of CO2 production in the

DL. The paper concludes that recent increased CO2 concentrations in the

atmosphere may be linked with increased CO2 emissions from soil