The phrase "decreasing availability of" is correct and usable in written English.
You can use it any time you want to describe a situation where a resource or commodity is becoming less easy to obtain or find. For example: "The decreasing availability of natural resources is causing economic instability in many countries."
Decreasing availability of oil and gas is a benefit, not a disadvantage.
The researchers, writing in Nature, say the quick decline may in part have been due to decreasing availability of krill, one of the penguins' staple foods.
Chancellor Alistair Darling told parliament that the scheme "is a further step in our efforts to tackle these problems, which have widened in recent weeks, with the increasing cost and decreasing availability of lending by banks and building societies".
With decreasing availability of water for agriculture and increasing demand for rice production, an optimum use of irrigation water and phosphorus may guarantee sustainable rice production.
Some of these are the ever-increasing population, less availability of arable land, global climate changes and decreasing availability of water for agriculture (Takeda and Matsuoka, 2008).
Both pastoralists' observations and existing meteorological data analysis showed an increasing incidence of recurrent droughts with decreasing availability of grazing and water resources.
Law-enforcement officials in 38 U.S. cities, however, have reported decreased availability of cocaine since January 2007.
That suggests other factors may be at work beyond the pace of global growth.One candidate is decreased availability of trade finance.
In the fasting state, the decreased availability of glucose results in predominant metabolism of fatty acids by the myocardium.
Conclusions Cardiopulmonary bypass significantly decreases availability of arginine, citrulline, and nitric oxide metabolites in the postoperative period.
Therefore, the reduction in extracellular levels in castrates was not due to decreased availability of DA; most likely it was due to decreased release.
