Proximate environmental drivers of coral communities at Palmyra Atoll: Establishing baselines prior to removing a WWII military causeway

• Published in: Marine pollution bulletin Vol. 62; no. 8; pp. 1842 - 1851
• Main Authors: Williams, Gareth J., Knapp, Ingrid S., Maragos, James E., Davy, Simon K.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-08-2011; Elsevier
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Anthozoa - classification; Anthozoa - physiology; Applied ecology; Biological and medical sciences; Central Pacific; Cnidaria. Ctenaria; community structure; Coral communities; Coral decline; corals; correlation; Ecosystem; Ecotoxicology, biological effects of pollution; environmental factors; Environmental Monitoring - methods; Fundamental and applied biological sciences. Psychology; Geography; Geologic Sediments - analysis; Invertebrates; Marine; Marine and brackish environment; Military causeway; Military Personnel; Montipora; Pacific Ocean; Palmyra Atoll; Scleractinia; Sea water ecosystems; Sediment; sediments; Synecology; terraces; water flow; water pollution; World War II; Pacific Ocean; Syria, Palmyra; Palmyra Atoll; Coral decline; Sediment; Military causeway; Central Pacific; Coral communities; Sediments; Marine environment; Coelenterata; Coral; Atoll; Cnidaria; Invertebrata; Community; Military
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2011.05.002

► We modeled scleractinian coral cover and community structure with environment at Palmyra Atoll. ► Coral cover showed a negative relationship with levels of fine sediment influx. ► Fine sediment influx was the optimal predictor of coral community structure. ► Removing an existing WWII military causeway could increase sedimentation on the reefs. ► We predict negative impacts to the reefs if sedimentation were to increase as a result.
A management proposal aims to partly remove a WWII military causeway at Palmyra Atoll to improve lagoon water circulation and alleviate sedimentation stress on the southeast backreef, an area of high coral cover and diversity. This action could result in a shift in sedimentation across reef sites. To provide management advice, we quantified the proximate environmental factors driving scleractinian coral cover and community patterns at Palmyra. The proportion of fine sedimentation was the optimal predictor of coral cover and changes in community structure, explaining 23.7% and 24.7% of the variation between sites, respectively. Scleractinian coral cover was negatively correlated with increases in fine sedimentation. Removing the causeway could negatively affect the Montipora corals that dominate the western reef terrace, as this genus was negatively correlated with levels of fine sedimentation. The tolerance limits of corals, and sediment re-distribution patterns, should be determined prior to complete removal of the causeway.