a. Develop and implement a range-wide monitoring program: Information on population status is needed throughout the Caribbean, Gulf of Mexico, and western Atlantic, both inside and outside U.S. jurisdiction. Additionally, monitoring is required to evaluate the effectiveness of specific actions to abate threats in targeted local areas. Thus, a range-wide monitoring program for elkhorn and staghorn corals needs to be implemented, as substantial variation in population status is known (e.g., eastern Caribbean populations of elkhorn coral are more genotypically diverse and have higher colony density than western Caribbean populations (Baums et al. 2006)). Clearly, this spatial scale requires extensive international cooperation and coordination as the majority of both species lie outside of U.S. territories. Funding and cooperative mechanisms must be identified to enable standardized monitoring throughout this extensive geo-political area. The program will be implemented at two scales —abundance and demographic monitoring. Initiation: Immediately. Duration: On-going. Cost (for all sub-actions): $1,000,000 per year.
i. Implement a habitat-stratified random sampling approach for abundance assessment: To address Recovery Criterion 1 (population abundance), a habitat-stratified random sampling approach is required throughout these species’ ranges. By estimating an absolute colony density and relative abundance (percent cover) within each habitat strata, these estimates can be extrapolated to the entire species range with a quantifiable level of confidence. Miller et al. (2007, 2008b) have executed this type of sampling throughout the Florida Keys, and this program could be used as a model, repeated on a five year interval, to evaluate Criterion 6. To facilitate development of this abundance assessment, high-quality habitat maps must be produced (Action 4b). Existing and potential habitat, based on historic occurrence, needs to be inventoried and characterized. This will require defining what quality of habitat is necessary for recovery, including parameters for the benthos and water column. The characterization will be accomplished using a combination of tools (e.g., remotely-sensed data, in situ observations). Primary focus will be on U.S. jurisdictions, but international habitats are also necessary for recovery.
ii. Develop and implement a standardized demographic approach to monitoring: In order to evaluate Recovery Criteria related to recruitment and genotypic diversity, a standardized demographic approach to monitoring (e.g., Williams et al. 2006), including assessment of recruitment and genotyping of colonies within established plots, should be implemented where feasible (i.e., intermediate density stands). The lesser physical stability of individual staghorn coral colonies makes them less amenable than elkhorn coral to this approach but should be attempted (see Knowlton et al. (1990) for cable tie marking and “stick diagram” approach for tracking tagged colonies). A standardized demographic approach will also maximize the utility of the data for population modeling and projection and provides the best opportunity to
determine: 1) the relative importance of various threats (e.g., predation, disease, breakage), and 2) if the prevalence and impact of these threats is changing over time (see Williams and Miller 2012). Permanent plots and marked colonies should be established in all U.S. jurisdictions and multiple additional areas/countries. Additional standardized protocols should be established for thickets, where individual colonies can not be reliably delineated. Thicket protocols might involve standard quadrat/percent cover sampling and/or video mosaics combined with in situ prevalence estimates for different types of threats and should also include measurements of the size and spatial extent of the thickets. It may also be appropriate to include low-altitude aerial photographs with ground truthing.
Recovery Plan for Elkhorn and Staghorn Corals
iii. Evaluate robust reference populations: Alongside the distributed effort on demographic monitoring of population status, a minimum of three to five robust reference populations (extant thickets) will be targeted for each species spread throughout the range for intensive monitoring and research to determine potential demographic, genetic, and/or environmental factors that may account for their robust status. Many aspects of uncertainty delineated in this plan (e.g., predation and disease carrying capacity, sexual and asexual recruitment rates in healthy populations) can be addressed by comparing such robust reference populations with nearby populations which are in a more typical, degraded state. Environmental, toxicological, and ecological parameters should be monitored at these robust reference populations and nearby degraded populations (suggested as part of the demographic monitoring described in Action 5aii, above) to discern the causal differences.
This program may include a coarser-level field protocol to determine these species’ statuses at each site through time. The appropriate protocol must be developed; however, it should include both species-focused parameters and environmental parameters.
iv. Periodically monitor water quality parameters range-wide: Identify and quantify a suite of contaminants (e.g., pesticides, pharmaceuticals, heavy metals, polycyclic aromatic
hydrocarbons, personal care products) to be monitored in both the water column and in sediments. This type of analysis is somewhat expensive and only needs to be done periodically to determine if these compounds are present in the coral reef ecosystem. If found, monitoring for specific compounds should be conducted routinely to track trends. Additionally, quarterly sampling for the more standardized oceanographic parameters, such as nutrients, salinity, chlorophyll a, pH, alkalinity, TOC, DOM, turbidity, etc. should be performed.
b. Identify and map genotypes: All monitoring and in-water inventory activities should include biopsy sampling to analyze genotypic diversity in the monitored populations. This information should be tracked in an inventory database for these species, as described in Action 4a, above and coordinated with Action 3a (Genetic tool development).
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