Ecosystem Structure, Function, and Change Paper

(Great Lakes)

Shantera Bell

October 26, 2015

SCI/256

UOP

The Great Lakes region is rich with life and full of native species well adapted to survival. However, since the early 1800s, many non-native plants, animals and microscopic organisms have been introduced into the Great Lakes, either accidentally or intentionally. Great Lakes native species are diverse and interesting and contribute to a healthy ecosystem. There are many unique and interesting birds, fish and plants found in Michigan and throughout the region that are integral to the health of the Great Lakes ecosystem. More than 140 species of birds depend on Michigan’s coastal habitat during their life cycle. Coastal wetlands, beaches, sand dunes and remote islands provide food and shelter for both resident and migratory species.

Waterfowl such as Canvasback and Scaup are among the many species that use coastal wetlands as stopover sites to rest and refuel. Shorebirds including the endangered piping plover fly thousands of miles to nest on undisturbed beaches and remote Great Lakes islands.

Because of their use of the coastal lands, there are thousands of great locations to see both resident and migratory bird species throughout Michigan and the Great Lakes region. State parks, national parks, wildlife refuges and sanctuaries throughout the state all provide good bird-watching opportunities. Some sites along Michigan’s Great Lakes shoreline are even considered birding “hotspots” due to the number of species that pass through each spring and fall. More than 160 species of freshwater fish inhabit the waters of the Great Lakes.

Ancient fish, such as Lake Sturgeon and Longnose Gar also inhabit waters of the Great Lakes region. These fish have unique attributes that have allowed them to survive for millions of years. Each family of fishes in the Great Lakes region has physical traits that set it apart from others, called distinguishing characteristics.

As far as the plants goes, from wildflowers to cattails to dune grasses — plants provide pleasing backdrops and picturesque panoramas. However, they also contribute much more than beauty to a landscape. For example, in the Great Lakes, native shoreline plants help hold surface sands in place and provide food and shelter for wildlife.

Many coastal Great Lakes plants are well adjusted to hard living, managing to survive the threat of invasive species, harsh beach climates and fluctuating water levels.

The major structural and functional dynamics of your selected ecosystem:

GLERL’s Ecosystem Dynamics research program is building a strong base of understanding for the structure of the Great Lakes ecosystem and how its ecosystem processes function and respond to changing environmental conditions. An important goal of the Ecosystem Dynamics research is to study human-generated factors threatening the health and services of the Great Lakes. For example, long-term research in lakes Michigan and Huron focuses on how invasive species disrupt ecosystem processes affecting food webs, such as the decline of zooplankton populations or shifts in their migratory patterns, which can affect recreational and commercial fishing in the lakes.

In Lake Erie, the scientists are investigating the effect of harmful algal blooms (HABs) on the Great Lakes ecosystem and human health. They are particularly interested in the role played by invasive mussels and nutrients (phosphorus and nitrogen contained in fertilizers) in promoting the growth of HABs as well as year to year weather related factors that can affect the intensity of the HABs. Results from this research will provide valuable information for managing services that are threatened by HABs such as drinking water supplies, swimming and other recreational activities. To meet NOAA’s goal of a healthy Great Lakes, we must take a proactive approach in the conduct of our research to keep pace with the rapidly changing ecosystem conditions of the lakes. To improve our ability to predict these changes, Ecosystem Dynamics research supports the development and use of physical and ecological modeling at GLERL. The forecasts generated by these models provide resource managers with valuable information on future ecosystem conditions, supporting timely decision-making in managing our Great Lakes. Outcomes from Ecosystem Dynamic research play a critical role in preparing our region to more effectively restore and protect the Great Lakes and their ecosystem services.

Recognizing the value of a long-term perspective on how ecosystems change over time, GLERL has invested in researching the southern basin of Lake Michigan since the 1970s. GLERL's focus on Lake Michigan has led to the establishment of the Long-Term Research (LTR) program. GLERL's LTR approach integrates a core set of long-term observations on biological, chemical, and physical variables, with short-term process-based studies for understanding ecosystem change. Such information is essential for the development of new concepts, models, and forecasting tools to explore impacts of various stressors on the ecosystem.

How humans may have affected the cycling of matter in ecosystems, including effects to the nitrogen, phosphorus, or carbon cycle?

The most significant change in the structure of ecosystems has been the transformation of approximately one quarter (24%) of Earth’s terrestrial surface to cultivated systems. More land was converted to cropland in the 30 years after 1950 than in the 150 years between 1700 and 1850.

Between 1960 and 2000, reservoir storage capacity quadrupled; as a result, the amount of water stored behind large dams is estimated to be three to six times the amount held by natural river channels this excludes natural lakes. Since 1750, the atmospheric concentration of carbon dioxide has increased by about 34% (from about 280 parts per million to 376 parts in 2003). Approximately 60% of that increase (60 parts per million) has taken place since 1959. The effect of changes in terrestrial ecosystems on the carbon cycle reversed during the last 50 years. Those ecosystems were on average a net source of CO2 during the nineteenth and early twentieth centuries (primarily due to deforestation, but with contributions from degradation of agricultural, pasture, and forestlands) and became a net sink sometime around the middle of the last century (although carbon losses from land use change continue at high levels) (high certainty). Factors contributing to the growth of the role of ecosystems in carbon sequestration include afforestation, reforestation, and forest management in North America, Europe, China, and other regions; changed agriculture practices; and the fertilizing effects of nitrogen deposition and increasing atmospheric CO2 (high certainty).

The total amount of reactive, or biologically available, nitrogen created by human activities increased ninefold between 1890 and 1990, with most of that increase taking place in the second half of the century in association with increased use of fertilizers. (See Figures 1.5 and 1.6.) A recent study of global human contributions to reactive nitrogen flows projected that flows will increase from approximately 165 teragrams of reactive nitrogen in 1999 to 270 teragrams in 2050, an increase of 64%. More than half of all the synthetic nitrogen fertilizer (which was first produced in 1913) ever used on the planet has been used since 1985.

The use of phosphorus fertilizers and the rate of phosphorus accumulation in agricultural soils increased nearly threefold between 1960 and 1990, although the rate has declined somewhat since that time. The current flux of phosphorus to the oceans is now triple that of background rates (approximately 22 tera grams of phosphorus per year versus the natural flux of 8 tera grams).

How knowledge about that ecosystem’s structure and function can help or has helped to develop plans for its restoration or management?

River mouth ecosystems, or freshwater estuaries, are the focus of human and wildlife interactions with the Great Lakes. They are highly valued as the region’s urban, industrial, shipping and recreational centers; and home to recreational harbors, wildlife viewing and production, beaches and urban riverfronts. River mouths are also both the mixing zones where nutrients from upstream watersheds are incorporated into the Great Lakes ecosystem and important sites for fish nursery and passage to upstream spawning grounds. These estuarine processes have been broadly altered through watershed land use, floodplain development, harbor channel dredging, wetland filling, urban storm water, shoreline hardening, road and bridge construction, pier construction and the introduction of non-indigenous species. Despite the importance of river mouth ecosystems to humans, fish and wildlife, very little is known about how these ecosystems function or how anthropogenic changes have altered those natural processes. Our lack of understanding severely limits our ability to manage or restore these ecosystems effectively and efficiently.

References

GreenFactScientificBoard.com

www.miseagrant.umich.edu

wwwglerl.noaa.gov/pubs/posters/posters.html