New paper on intertidal alternate states

UMaine Alert

Posted: April 19, 2024 - 1:32 PM

At approximately 9:24 a.m. on Friday, April 19, a University of Maine graduate student was struck by a university vehicle on Long Road at the University of Maine campus in Orono. The student reports that they are at a local hospital with minor injuries.

Emergency services, including the Orono Fire Department, University Volunteer Ambulance Corps, University of Maine Police Department, Orono Police Department and Penobscot County Sheriff’s Office responded to the scene.

The university vehicle involved in the incident was a Chevrolet Express van. It was being operated by a university employee.

Counseling services and support are available for students, faculty or staff who may have been affected. The Counseling Center can be reached at 207-581-1392 and the Dean of Students Office can be reached at 207-581-1406.

The scene has been cleared and Long Road is now accessible. An investigation is being conducted by the University of Maine Police Department with assistance from the Penobscot County Sheriff’s Office Crash Reconstruction Unit. Any witnesses to the incident are encouraged to contact Lt. Noel Santiago at noel.santiago@maine.edu.

April 7, 2017 Climate Change, New England Environment, Publications

Menge, B. A., M. Bracken, J. Lubchenco, and H. M. Leslie. 2017. Alternative state? Experimentally-induced Fucus canopy persists 38 years in an Ascophyllum-dominated community. Ecosphere, doi: 10.1002/ecs2.1725.

Experimental tests of the hypothesis that ecological communities can exist in “multiple stable states” are rare, and some argue, impossible, because of the unlikelihood that any system will meet the necessary criteria. These are that alternative states (1) are in the same location, (2) experience the same environment, (3) persist for multiple generations, (4) resist repeated perturbations, and (5) result from a pulse manipulation. In 1974, we initiated an experiment testing the ability of Ascophyllum nodosum-dominated rocky intertidal communities to recover from complete canopy removal. Manipulations were monitored frequently for 5 yr after clearance and resurveyed again after a 35-yr hiatus. After clearance, Ascophyllum was replaced immediately by another fucoid alga, Fucus spp, which continued to dominate the space through 1979 despite regular annual recruitment by Ascophyllum. Observations in 2009 revealed that Fucus spp. still dominated the cleared plots. Surveys in 2011 and 2013 demonstrated that Fucus persisted in experimental plots and Ascophyllum persisted in adjacent, unmanipulated plots. All criteria for testing an alternative state were met. Fucus persisted through multiple generations of both fucoids, a steady annual rain of recruits of both species, a high frequency of storm-driven perturbations, and it resulted from a pulse manipulation. Likely mechanisms include poor Ascophyllum recruitment directly under the Fucus spp. canopy despite abundant recruitment in adjacent areas, self-maintenance by Fucus spp. through high recruitment and fast growth, and recruitment facilitation of Fucus by the barnacle Semibalanus balanoides. Several lines of evidence indicate that other possible mechanisms including indirect facilitation of fucoids through predation on competitors (mussels), and positive or negative effects of littorine grazing, are unlikely. Although prior results in Maine suggested that the mussel Mytilus edulis was an alternative stable state, the new results suggest that Fucus spp. was the alternative state to Ascophyllum. During the nearly four decades of this experiment, a number of important species including fucoids, littorine grazers, and mussels all declined in abundance, most likely due to climate change. The presumed impact of climate change makes prediction of the long-term response of this system difficult, but it already differs dramatically from its structure in the 1970s.