Marine sci­en­tists have grown increas­ingly con­cerned over the loss of marine bio­di­ver­sity and the need to under­stand the con­se­quences of these changes has become vital. Pro­ceed­ings of the National Academy of Sci­ences (PNAS) has pub­lished the find­ings of a study using sea­weed species rich­ness co-​​authored by Matthew Bracken, assis­tant pro­fessor of biology at the Marine Sci­ence Center at North­eastern University.

Titled “Com­ple­men­tarity in marine bio­di­ver­sity manip­u­la­tions: Rec­on­ciling diver­gent evi­dence from field and meso­cosm exper­i­ments”, the paper con­tends that short-​​term exper­i­ments detect only a subset of pos­sible mech­a­nisms that operate in the field over the longer term because they lack suf­fi­cient envi­ron­mental het­ero­geneity to allow expres­sion of niche dif­fer­ences. The study sug­gests that short-​​term exper­i­ments are not lengthy enough to cap­ture population-​​level responses. It is likely that many pub­lished exper­i­ments under­es­ti­mate the strength of diver­sity on ecosystem processes in nat­ural ecosystems.

Bio­di­ver­sity is changing on a global scale due to fac­tors such as habitat destruc­tion by humans,” said Bracken. “This study allowed us to explore the con­se­quences of bio­di­ver­sity change using sea­weed species rich­ness. The results are exciting because as our exper­i­ments became more real­istic, and were con­ducted for a longer time, the effects of bio­di­ver­sity on pro­duc­tion were stronger.”

Until recently, the ability of sci­en­tists and researchers to use existing data to assess vari­a­tion in the strength of diver­sity effects has been lim­ited by dif­fer­ences in approaches spe­cific to par­tic­ular study sys­tems. Many studies of ter­res­trial plant species rich­ness have found diver­sity effects, but this pat­tern has been less gen­eral in marine sys­tems where many studies have found little or no effects.

The article fea­tured in PNAS asserts that the effect of sea­weed species rich­ness on sea­weed bio­mass dif­fered dra­mat­i­cally between short– and long-​​term field exper­i­ments. The results of the study sup­port the idea that exper­i­mental dura­tion influ­ences the strength of the diver­sity effect. In con­clu­sion, researchers sug­gest that short-​​term assembly exper­i­ments and longer-​​term exper­i­ments in nat­ural marine sys­tems in com­bi­na­tion might allow one to better clarify the mech­a­nisms that do and do not operate to link diver­sity and function.

For more infor­ma­tion, please con­tact Samantha Fodrowski at 617–373-5427 or s.​fodrowski@​neu.​edu.

About North­eastern

Founded in 1898, North­eastern Uni­ver­sity is a pri­vate research uni­ver­sity located in the heart of Boston. North­eastern is a leader in inter­dis­ci­pli­nary research, urban engage­ment, and the inte­gra­tion of class­room learning with real-​​world expe­ri­ence. The university’s dis­tinc­tive coop­er­a­tive edu­ca­tion pro­gram, where stu­dents alter­nate semes­ters of full-​​time study with semes­ters of paid work in fields rel­e­vant to their pro­fes­sional inter­ests and major, is one of the largest and most inno­v­a­tive in the world. The Uni­ver­sity offers a com­pre­hen­sive range of under­grad­uate and grad­uate pro­grams leading to degrees through the doc­torate in six under­grad­uate col­leges, eight grad­uate schools, and two part-​​time divi­sions. For more infor­ma­tion, please visit www​.north​eastern​.edu.