Historical Connectivity and Demography of the Ferocious Reef Crab, Eriphia ferox (Crustacea; Eriphiidae), Demonstrate That Taoyuan Algal Reef Is an Essential Population Source Along the East Taiwan Strait

The east Taiwan Strait is largely fringed by sandy and muddy habitats. However, a massive algal reef made of crustose coralline algae has been found along the coast off Taoyuan city in northwestern Taiwan. The porous structure of Taoyuan Algal Reef harbors high abundance and diversity in marine organisms, including the ferocious reef crab, Eriphia ferox. Such a pivotal geographic location and unique ecological features make Taoyuan Algal Reef a potential stepping stone connecting biotic reefs in the east Taiwan Strait, South China Sea to the south, and even the high latitude of Japan to the north. In this study, we examined the population connectivity and historical demography of E. ferox by analyzing mitochondrial cytochrome oxidase I (COI) fragments of 317 individuals sampled from 21 localities in the northwestern Pacific. Our analyses of haplotype network and pairwise FST comparisons revealed a lack of phylogeographical structure among E. ferox populations, implying the existence of a migration corridor connecting the South and East China Seas through the east Taiwan Strait. Multiple lines of evidence, including significant values in neutrality tests, unimodally shaped mismatch distributions, and Bayesian skyline plots elucidated the rapid population growth of E. ferox following the sea-level rise after Last Glacial Maximum (ca. 2–10 Ka). Such demographic expansion in E. ferox coincided with the time when Taoyuan Algal Reef started to build up around 7,500 years ago. Coalescent migration analyses further indicated that the large and continuous E. ferox population exclusively found in Datan Algal Reef, the heart of Taoyuan Algal Reef, was a source population exporting migrants both northward and southward to the adjacent populations. The bidirectional gene flow should be attributed to larval dispersal by ocean currents and secondary contact due to historical population expansion. Instead of serving as a stepping stone, our results support that Taoyuan Algal Reef is an essential population source for biotic reef-associated species along the east Taiwan Strait, and highlight the importance of conserving such a unique ecosystem currently threatened by anthropogenic development.

Distinguishing regeneration from degradation in coral ecosystems: the role of value

In this paper I argue that the value attributed to coral reefs drives the characterisation of evidence for their regeneration or degradation. I observe that regeneration and degradation depend on an understanding of what an ecosystem looks like when undegraded (a baseline), and that many mutually exclusive baselines can be given for any single case. Consequently, facts about ecological processes are insufficient to usefully and non-arbitrarily characterise changes to ecosystems. By examining how baselines and the value of reefs interact in coral and algal reef examples, I argue that considering the value of an ecosystem is a necessity when describing processes like regeneration and degradation. This connects value as studied in socio-ecological and economic research with values as discussed in the philosophy of science literature. It also explains why such a broad range of processes may be considered regenerative, including those which introduce significant novelty, as well as pointing towards ways to mediate related debates, such as those surrounding novel and ‘pristine’ ecosystems.

A UAV-RTK-LIDAR SYSTEM MEASUREMENTS OF WAVE ENERGY DISSIPATION OVER A SANDY BEACH AND AN ALGAL-REEF AREA

Wave energy dissipation is a significant factor affecting coastal hydrodynamics, coastline morphology, wave height transformation, and the nutrient uptake in the coral reef (Huang, Lenain et al. 2012). However, it is difficult to be measured since accurate and spatial-distributed measurements of sea surface elevations are required to compute this quantity. We used a UAV-RTK-Lidar system to test the possibility for the measurements of wave energy dissipation. The UAV system was validated to able to measure the ocean wave properties (Huang, Yeh et al. 2018). Two field experiments of measuring energy dissipation were conducted over an algal-reef and a sandy beach site, respectively. Nine and eight flights of UAV measurements on the algal reef and sandy beach were conducted for one tidal cycle. The measurements of wave properties by UAV were compared with those of in-situ instruments using pressure sensors.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/fBLbsBuK4AA

Natural Gas or Algal Reef: Survey-Based Valuations of Pro-Gas and Pro-Reef Groups Specifically for Policy Advising

Much energy-related construction causes environmental concern. Sometimes the environmental issue is so huge that it is difficult to make a policy decision even with the assistance of traditional valuation techniques. The third natural gas receiving station at Datan, Taiwan, is one example of this. The construction would be beneficial to energy security, economic development, and particulate matter (PM) 2.5 reduction. However, it would destroy a precious algal reef, which is a habitat for endangered species, biodiversity, and a unique ecological system. Thus, we used willingness-to-pay to show the strength of both pro-energy and pro-ecology opinions specifically to help with decision-making. First, respondents were asked to choose between the gas station and the reef. Then they were asked about their willingness to pay for that choice. We then estimated parametric/nonparametric models—traditional probit, structured probit, and Turnbull—to obtain reliable estimates. We found that the per-person value for pro-gas-station respondents was higher than that for pro-reef respondents, while the percentage of pro-reef respondents was higher than the percentage of pro-gas-station respondents. These results together form a clear policy implication for this case.