scholarly journals The use of pseudo-multivariate standard error to improve the sampling design of coral monitoring programs

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8429
Author(s):  
Luis M. Montilla ◽  
Emy Miyazawa ◽  
Alfredo Ascanio ◽  
María López-Hernández ◽  
Gloria Mariño-Briceño ◽  
...  
Keyword(s):  
Community Structure ◽  
Coral Reef ◽  
Standard Error ◽  
Scleractinian Coral ◽  
Statistical Power ◽  
Sampling Design ◽  
Sampling Effort ◽  
Monitoring Programs ◽  
Coral Monitoring

The characteristics of coral reef sampling and monitoring are highly variable, with numbers of units and sampling effort varying from one study to another. Numerous works have been carried out to determine an appropriate effect size through statistical power; however, these were always from a univariate perspective. In this work, we used the pseudo multivariate dissimilarity-based standard error (MultSE) approach to assess the precision of sampling scleractinian coral assemblages in reefs of Venezuela between 2017 and 2018 when using different combinations of number of transects, quadrats and points. For this, the MultSE of 36 sites previously sampled was estimated, using four 30m-transects with 15 photo-quadrats each and 25 random points per quadrat. We obtained that the MultSE was highly variable between sites and is not correlated with the univariate standard error nor with the richness of species. Then, a subset of sites was re-annotated using 100 uniformly distributed points, which allowed the simulation of different numbers of transects per site, quadrats per transect and points per quadrat using resampling techniques. The magnitude of the MultSE stabilized by adding more transects, however, adding more quadrats or points does not improve the estimate. For this case study, the error was reduced by half when using 10 transects, 10 quadrats per transect and 25 points per quadrat. We recommend the use of MultSE in reef monitoring programs, in particular when conducting pilot surveys to optimize the estimation of the community structure.

scholarly journals Transects, quadrats, or points? What is the best combination to get a precise estimation of a coral community?

2019 ◽  
Author(s):  
Luis M. Montilla ◽  
Emy Miyazawa ◽  
Alfredo Ascanio ◽  
María López-Hernández ◽  
Gloria Mariño-Briceño ◽  
...  
Keyword(s):  
Community Structure ◽  
Coral Reef ◽  
Effect Size ◽  
Standard Error ◽  
Scleractinian Coral ◽  
Statistical Power ◽  
Coral Community ◽  
Sampling Effort ◽  
Precise Estimation

ABSTRACTThe characteristics of coral reef sampling and monitoring are highly variable, with numbers of units and sampling effort varying from one study to another. Numerous works have been carried out to determine an appropriate effect size through statistical power, however, always from a univariate perspective. In this work, we used the pseudo multivariate dissimilarity-based standard error (MultSE) approach to assess the precision of sampling scleractinian coral assemblages in reefs of Venezuela between 2017 and 2018 when using different combinations of number of transects, quadrats and points. For this, the MultSE of 36 sites previously sampled was estimated, using four 30m-transects with 15 photo-quadrats each and 25 random points per quadrat. We obtained that the MultSE was highly variable between sites and is not correlated with the univariate standard error nor with the richness of species. Then, a subset of sites was re-annotated using 100 uniformly distributed points, which allowed the simulation of different numbers of transects per site, quadrats per transect and points per quadrat using resampling techniques. The magnitude of the MultSE stabilized by adding more transects, however, adding more quadrats or points does not improve the estimate. For this case study, the error was reduced by half when using 10 transects, 10 quadrats per transect and 25 points per quadrat. We recommend the use of MultSE in reef monitoring programs, in particular when conducting pilot surveys to optimize the estimation of the community structure.

scholarly journals Metamorphosis of a Scleractinian Coral in Response to Microbial Biofilms

2004 ◽  
Vol 70 (2) ◽  
pp. 1213-1221 ◽  
Author(s):  
Nicole S. Webster ◽  
Luke D. Smith ◽  
Andrew J. Heyward ◽  
Joy E. M. Watts ◽  
Richard I. Webb ◽  
...  
Keyword(s):  
Community Structure ◽  
Coral Reef ◽  
Scleractinian Coral ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Marine Invertebrate ◽  
Principal Component ◽  
Coralline Algae ◽  
Larval Metamorphosis ◽  
Microbial Biofilms ◽  
Wide Range

ABSTRACT Microorganisms have been reported to induce settlement and metamorphosis in a wide range of marine invertebrate species. However, the primary cue reported for metamorphosis of coral larvae is calcareous coralline algae (CCA). Herein we report the community structure of developing coral reef biofilms and the potential role they play in triggering the metamorphosis of a scleractinian coral. Two-week-old biofilms induced metamorphosis in less than 10% of larvae, whereas metamorphosis increased significantly on older biofilms, with a maximum of 41% occurring on 8-week-old microbial films. There was a significant influence of depth in 4- and 8-week biofilms, with greater levels of metamorphosis occurring in response to shallow-water communities. Importantly, larvae were found to settle and metamorphose in response to microbial biofilms lacking CCA from both shallow and deep treatments, indicating that microorganisms not associated with CCA may play a significant role in coral metamorphosis. A polyphasic approach consisting of scanning electron microscopy, fluorescence in situ hybridization (FISH), and denaturing gradient gel electrophoresis (DGGE) revealed that coral reef biofilms were comprised of complex bacterial and microalgal communities which were distinct at each depth and time. Principal-component analysis of FISH data showed that the Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Cytophaga-Flavobacterium of Bacteroidetes had the largest influence on overall community composition. A low abundance of Archaea was detected in almost all biofilms, providing the first report of Archaea associated with coral reef biofilms. No differences in the relative densities of each subdivision of Proteobacteria were observed between slides that induced larval metamorphosis and those that did not. Comparative cluster analysis of bacterial DGGE patterns also revealed that there were clear age and depth distinctions in biofilm community structure; however, no difference was detected in banding profiles between biofilms which induced larval metamorphosis and those where no metamorphosis occurred. This investigation demonstrates that complex microbial communities can induce coral metamorphosis in the absence of CCA.

scholarly journals Sampling requirements and approaches to detect ecosystem shifts

2020 ◽  
Author(s):  
Rosalie Bruel ◽  
Easton R. White
Keyword(s):  
Statistical Power ◽  
Ice Cores ◽  
Ecosystem Change ◽  
Sample Collection ◽  
Labor Costs ◽  
Sample Processing ◽  
Community Assemblage ◽  
Monitoring Programs ◽  
High Statistical Power

AbstractEnvironmental monitoring is a key component of understanding and managing ecosystems. Given that most monitoring efforts are still expensive and time-consuming, it is essential that monitoring programs are designed to be efficient and effective. In many situations, the expensive part of monitoring is not sample collection, but instead sample processing, which leads to only a subset of the samples being processed. For example, sediment or ice cores can be quickly obtained in the field, but they require weeks or months of processing in a laboratory setting. Standard sub-sampling approaches often involve equally-spaced sampling. We use simulations to show how many samples, and which types of sampling approaches, are the most effective in detecting ecosystem change. We test these ideas with a case study of Cladocera community assemblage reconstructed from a sediment core. We demonstrate that standard approaches to sample processing are less efficient than an iterative approach. For our case study, using an optimal sampling approach would have resulted in savings of 195 person-hours—thousands of dollars in labor costs. We also show that, compared with these standard approaches, fewer samples are typically needed to achieve high statistical power. We explain how our approach can be applied to monitoring programs that rely on video records, eDNA, remote sensing, and other common tools that allow re-sampling.

Optimising methods for monitoring programs: Olympic marmots as a case study

2008 ◽  
Vol 35 (8) ◽  
pp. 788 ◽  
Author(s):  
Julia Witczuk ◽  
Stanislaw Pagacz ◽  
L. Scott Mills
Keyword(s):  
Large Scale ◽  
Sampling Design ◽  
Survey Design ◽  
Monitoring Program ◽  
Olympic National Park ◽  
Monitoring Programs ◽  
Stage Process ◽  
Declining Species ◽  
Changes Over Time

Monitoring of rare and declining species is one of the most important tasks of wildlife managers. Here we present a large-scale, long-term monitoring program for Olympic marmot (Marmota olympus) throughout its range across a logistically challenging mountainous park. Our multiple-stage process of survey design accounts for the difficulty imposed by access to remote habitats and funding constraints. The Olympic marmot is endemic to the Olympic Mountains, Washington State, USA. Although nearly all of its range is enclosed within Olympic National Park, declines and local extirpations of the species have been documented. We considered several possible alternative survey approaches, and propose a monitoring program designed to reflect extinction–recolonisation dynamics using presence–absence data. The sampling design is based on annual surveys of a set of at least 25 randomly selected clusters (closely located groups of sites with record of current or historical occupancy by marmots), and supplemented by sampling 15 never-occupied sites to test for new colonisations. The monitoring plan provides a framework that park managers can use for assessing changes over time in Olympic marmot distribution across the range of the species. Our sampling design may serve as a useful case study for establishing monitoring programs for other species with clumped distributions.

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