Caribbean-wide, long-term study of seagrass beds reveals local variations, shifts in community structure and occasional collapse

• Published in: PloS one 2014-03, Vol.9 (3), p.e90600
• Main Authors: van Tussenbroek, Brigitta I, Cortés, Jorge, Collin, Rachel, Fonseca, Ana C, Gayle, Peter M H, Guzmán, Hector M, Jácome, Gabriel E, Juman, Rahanna, Koltes, Karen H, Oxenford, Hazel A, Rodríguez-Ramirez, Alberto, Samper-Villarreal, Jimena, Smith, Struan R, Tschirky, John J, Weil, Ernesto
• Format: Article
• Language: English
• Subjects: Algae; Annual variations; Biology; Biomass; Biota; Caribbean Region; Coasts; Coral reefs; Earth Sciences; Environmental deterioration; Environmental Monitoring - methods; Environmental Monitoring - statistics & numerical data; Fishes; Grasses; Hurricanes; Hydrocharitaceae - growth & development; Morphology; Nutrients; Population Dynamics; Productivity; Sea turtles; Sediments; Studies; Thalassia testudinum; Water quality
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0090600

The CARICOMP monitoring network gathered standardized data from 52 seagrass sampling stations at 22 sites (mostly Thalassia testudinum-dominated beds in reef systems) across the Wider Caribbean twice a year over the period 1993 to 2007 (and in some cases up to 2012). Wide variations in community total biomass (285 to >2000 g dry m(-2)) and annual foliar productivity of the dominant seagrass T. testudinum (2000 g dry m(-2)) were found among sites. Solar-cycle related intra-annual variations in T. testudinum leaf productivity were detected at latitudes > 16°N. Hurricanes had little to no long-term effects on these well-developed seagrass communities, except for 1 station, where the vegetation was lost by burial below ∼1 m sand. At two sites (5 stations), the seagrass beds collapsed due to excessive grazing by turtles or sea-urchins (the latter in combination with human impact and storms). The low-cost methods of this regional-scale monitoring program were sufficient to detect long-term shifts in the communities, and fifteen (43%) out of 35 long-term monitoring stations (at 17 sites) showed trends in seagrass communities consistent with expected changes under environmental deterioration.