Sedimentary History of Mangrove Cays in Turneffe Islands, Belize: Evidence for Sudden Environmental Reversals

Mangrove Sedimentation and Response to Relative Sea-Level Rise

“…Hurricanes can devastate mangroves, causing windthrow and defoliation, which interrupt forest growth. These hurricanes can also erode the substrate and deposit unusually thick layers of sediment that result in forest mortality (Ellison 1999, McCloskey & Liu 2013. Subsurface processes identified following a storm include accretion or erosion that causes elevation change, shrinkage, root decomposition, root growth, and other changes of volume (Cahoon 2006, Smith et al 2009, Lovelock et al 2011b,…”

“…Clearly, there is a rate of SLR above which mangrove substrate cannot accumulate fast enough to keep pace with rising sea levels, but this rate remains difficult to determine from paleoenvironmental analyses, although high rates of adjustment have been identified. Peat sequences are interrupted by calcareous layers in other places, indicating periodic disruption by storms or seismic activity (McCloskey & Liu 2013). By contrast, the sea was at or above its present level for much of the past 7,000 years in the IndoPacific, and mangroves that occupied many of the coastal and deltaic plains that formed over this period have been replaced, with only a narrow fringe persisting along the modern shoreline.…”

Ancient Maya wood selection and forest exploitation: a view from the Paynes Creek salt works, Belize

“…Natural and anthropogenic processes and changes in forest composition impact foraging decisions in a dynamic feedback mechanism. In a coastal environment, changes in hydrology, including fresh water inputs and sea-level rise can impact forest patches through localized changes in nutrient balance, salinity, sedimentation, and inundation (Feller, 1995;McCloskey and Liu, 2013;Monacci et al, 2009Monacci et al, , 2011. Broader climatic affects, such as droughts, can cause considerable disruption to ecosystems, and has been linked to social change (Haug et al, 2003;Hodell et al, 1995;Kennett et al, 2012).…”

“…Extensive research on the environmental impacts on mangrove communities has recorded a variety of localized responses, including changes in forest composition, stature, and survival, although unfortunately there is limited high-resolution data for the time period associated with ancient Maya occupation (Ellison and Farnsworth, 1996;McCloskey and Liu, 2013;Monacci et al, 2009Monacci et al, , 2011. Ellison and Farnsworth (1996) note that, "direct and indirect anthropogenic impacts on mangal (mangrove communities) dwarf natural disturbances in their spatial scale and severity, and their temporal persistence, and are now considered to be major determinants of mangrove community composition and extent world-wide.…”

“…Sediment cores along the coast reveal a Holocene history of mangrove peat formation keeping pace with sea-level rise (MacIntyre et al, 2004;McKee and Faulkner, 2000). Localized disturbances and changes in the rate of net sea-level rise create periods of disrupted vegetation and sedimentation (McCloskey and Liu, 2013;McKee and Faulkner, 2000;Monacci et al, 2011). The abandonment of the Early Classic site, Chan B'i, and later inundation of the salt works in Paynes Creek, may be related to mangrove disturbance.…”