The Effects of Wave Force on Species Richness and Abundance
– a study of Clayoquot Sound’s First Beach, and a literature review

Introduction
The primary research aim of the study presented here was to determine the effect of exposure to wave force on the distribution of macrofauna in sandy beaches on Flores Island, Clayoquot Sound.

Many similar—albeit generally more complex—studies can be found in the literature, such as McLachlan et al. (1993), which examined the control exerted by the physical environment of beaches on “species richness, abundance, and biomass of the intertidal benthic macrofauna”, where the beaches examined occupied the spectrum from reflective to dissipative in their wave regimes.

The study, along with others described below, found that species richness is highest on dissipative beaches where macrofauna exposure to wave energy is least and species richness is lowest on reflective beaches where exposure to wave energy is highest.

In keeping with most temperate beaches (Schlacher et al., 2008), the beaches of Flores Island are “low gradient dissipative” (Gardner, 2015, p. 35), thus predicting a relatively high species richness and abundance; however, the particular orientation of these beaches makes “them subject to energetic wave action” (p. 35), thus confounding to an uncertain degree expectations regarding species richness and abundance.

Another fact of the morphology of the south short of Flores Island is the limited prevalence of tidal flats and estuaries (p. 30), which—as will be discussed below—can be an important variable in the occurrence of species on nearby beaches.

Further, while eolian processes and systems of dunes are critical morphological features of many beaches and thus determinative in species richness and abundance, “dunes are not well-developed on the south shore of Flores Island” (p. 49), where the best examples are found on Second Beach – not on First or “Stinking Seaweed” Beach where the study was conducted; eolian factors and dunes were thus not a variable under consideration in the present study, and thus are also not covered in the literature review conducted and presented below. A minor secondary research aim was the examination of the effect of macrofauna on beaches via bioturbation; given the secondary nature of this aim, bioturbation is not a point of focus in the literature review conducted.

Another primary aim of the present study was an extensive literature review, in order to properly understand, situate, and motivate the research conducted, and to interpret and place into context the results obtained.
As will be noted, the broadest driving concern is environmental, given the threats posed to sandy beaches and their ecologies, particularly by way of climate change, along with other more direct human interventions, and given the environmental, ecological, and socio-historical prominence of Clayoquot Sound (Greenpeace, n.d.).

For example, one motivation for the study was for it to be an initial step in determining the potential for the arthropod macrofauna sampled to act as indicator species for the ecological health of the beaches of Clayoquot Sound, ideally enabling quicker, more cost-effective monitoring methods; more on this below.

Given the pressures of climate change, having spatially and temporally extensive data is of paramount importance, which in turn demands that data collection be as efficient as possible.
In terms of the potential for the use of an indicator species for sandy beaches, the story of the significant declines in marbled murrelet in Clayoquot Sound—as much as 60% by one estimate (Burger, 1995, p. 295)—should provide both an exemplar and a wakeup call; “the Marbled Murrelet’s sensitivity to changes in its forest and marine environments make it valuable as an “indicator” species for the health of these ecosystems” (BHAS, 2015) and serves as a potential model for the sort of indicator species which would be ideal in the monitoring of sandy beach ecologies.

More broadly, a chief hope for the present study was to contribute data on beach morphologies and ecologies, data which might serve to fill in research gaps critical to ecological theory on these ecosystems and related conservation efforts.

Background
In an extensive article, Schlacher et al. (2008) sets out the key definitional features of sandy beach ecosystems, the issues which complicate data collection and sampling of sandy beach study, challenges facing efforts to manage beaches, and the impacts of climate change.

The key motivation for the article is the observation that beaches are unique in their vulnerability to threats posed by population growth, demographic shifts

Compare and contrast the factors of an internal and external analys...