In the 1980s, I spent a year investigating aquatic ecosystems of small streams in watersheds occupied by the city of Baltimore, Maryland. The study was a sort of scoping effort designed to help identify urban ecosystem indicators of impairment and restoration potential. We measured the abundance and diversity of sediment-dwelling invertebrate and finfish communities, and characterized associated habitat quality at each study site along a gradient of urban development intensity, from very rural to inner city.
Among our findings was a tidbit relevant to our lesson this week. Throughout the various sub watersheds and tributary stream networks, there were population remnants of many surprisingly sensitive species. In other words, where habitat patches remained, biodiversity reflected same, even when the chunks of quality habitat were small and very isolated. To me, this indicated surprisingly high potential for restoring healthier ecosystem structures and processes. There is nothing inherent about the watershed or the landscape excluding most species. The provision of appropriate habitat will bring them back. In my career since, which has been largely devote to the assessment and restoration of urban ecosystems, I have tested this hypothesis and it generally holds true. [While the technical details of the Baltimore work are not particularly relevant here, in case you have a more-than-casual interest you can find a couple of reports from the same program a decade later when the investigators had a rigorous grasp of methods and data analysis at http://www.dnr.state.md.us/irc/docs/00007773.pdf and
http://www.dnr.state.md.us/irc/docs/00008954.pdf . One report is for the more intensely urbanized waterways within Baltimore City, one is for the suburban-to-rural surrounding county. If you examine the tables listing fish species and their frequency in the samples, you will see my point. A number of species are represented very infrequently. But they do exist, and where habitat is appropriate they cannot only survive, they can thrive.]
The Shatt-al Arab marshes at the Arabian Gulf delta of the Tigris and Euphrates rivers is by light years the largest and most important wetland in the arid Middle East. The extensive reed marshes have existed for millennia, and many animal species evolved in-place and are characteristic. In addition, the marshes are crucial for feeding and resting during the enormous bird migrations that move from Africa to Europe and central Asia via Arabia and the Middle East. Furthermore, the energy fixed in the biomass of the reeds is broken down as detritus and the nutrients and energy passed along in turn to the marine ecosystems of the Gulf. In other words, the high levels of fish and shellfish production, and the reef life and rich fauna of mud and sand shallows throughout the Gulf, depend on the Shat-al Arab for trophic support. [Years ago in a souk in Kuwait I found a food shop selling fist-sized chunks of a hard, crumbly, yellow material. The texture was dry and chalky, but the flavor was oddly rich and slightly sweet. My Arabic being abysmal, and the shopkeeper’s English little better, I could not gain any traction on identifying the stuff. In typical fashion, when it became apparent that something interesting was happening, other shopkeepers, bystanders, and shoppers joined us, some whose English was excellent. I was able to establish that the material was used in soups, and often as a restorative for sickness or fatigue. It also devolved that it was a rustically old-fashioned ingredient—younger people in the market had never eaten it. But nobody could explain what it was or where it came from. I bought a chunk and took it to show the students in the class I was teaching at the Kuwait Foundation for the Advancement of Science. They gave me the same info—soup, sick—but also didn’t know what it was. A couple of them called their grandmothers overnight and the next day revealed that it was pollen collected from the Shatt-Al Arab reed marshes. I later found it to be generally available at at least a shop or two in any market, usually being purveyed alongside a similarly shaped and textured bone-dry chalky residue made from camel’s milk cheese or yogurt.]
For various political and military reasons the marshes, at the apex of the Gulf where Iran, Iraq, and Kuwait converge, are in a strategically vulnerable location. A useful history of the regional environment and its strategic importance is available at
http://www1.american.edu/ted/ice/iraniraq.htm .
Note that the material at the ICE web site, which is based on events of the Iran-Iraq war of the 1980s and published in 1998 according to the text, has, of course, been overtaken by more recent events. A thorough and up-to-date summary of the region, its environmental issues, and their relationships to various military conflicts written by Steven Lee Meyers was published last summer by the New York Times. It is available at:
http://www.nytimes.com/2010/06/13/science/earth/13shatt.html
and is the most objective [if you punch “Shatt-al Arab” into a browser, a substantive proportion of the hits will involve organizations with specific, not necessarily scientific, perspectives] and current summary I’ve been able to locate.
In brief, the waterways and wetlands of Shatt-Al Arab have been in gradual decline for a long time. Upstream waters were being committed, saline waters were intruding, pesticides and industrial chemical inputs were at risk levels in at least some locations, and some of the resources were being overharvested. However, during the Iran-Iraq war, things took an acute turn. Iraq re-engineered the hydrologic system to deliberately dry most of the area. The wetland character immediately altered, and most of the region shifted from an aquatic to an incipient and developing terrestrial system. Reedbeds declined, water disappeared, mud dried. It was a wide-scale environmental change of enormous consequences, affecting European songbird populations, Gulf fisheries, and most painfully, perhaps, the indigenous people whose culture was closely attuned to the big wetland.
The regional hydrology was re-plumbed following Saddam Hussein’s ouster to attempt to convert it back to wetland. But ecosystem recovery has lagged. Pre-war constraints—lack of fresh water flow, salt water encroachment, agriculture, and possibly transport of chemicals and sediments into the area from upstream—not only continue, the magnitude of some has increased. In addition, changes in landform occurring while the water was cut off may take a long time to re-equilibrate to the regional wetland character.
But restoration has at least begun. And the message from Baltimore’s intensely urbanized ecosystems is encouraging. As habitat quality recovers, much of the biota has the potential to follow suit. It will take time, there will be difficulties, and if regional constraints (such as low fresh water throughput) are not released, ultimate conditions may be far from ideal. But to the extent that hydrology and other physical and chemical conditions are restored, the ecological services flowing from the biology will again accrue.
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