Microhabitat influences morphospecies richness on Costa Rican rocky reefs


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Microhabitat influences morphospecies richness on Costa Rican rocky reefs

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Microhabitat influences morphospecies richness on Costa Rican rocky reefs
Translated Title:
El microhábitat influye la riqueza de morfoespecies en arrecifes piedrosos costarricenses
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Hawkins, Brooke
Medina, Eric
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Niche (Ecology) ( lcsh )
Nicho (Ecología) ( lcsh )
EAP Fall 2017
EAP Otoño 2017
Costa Rica--Guanacaste--Cuajiniquil
Costa Rica--Guanacaste--Cuajiniquil
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Microhabitat can be important in understanding small-scale habitat use of marine populations. This study examines the role of microhabitat, defined as a combination of substrate feature, as well as spatial heterogeneity on the biodiversity of rocky reefs off the coast of Cuajiniquil, Guanacaste, Costa Rica. We surveyed twenty quadrats from three sites, recording the benthic animal morphospecies we observed, the microhabitats they occupied, and measured physical attributes of each habitat. We found that stony caves harbor more morphospecies in a given area than other microhabitats, but that rocky flats and stony pools host more unique morphospecies in total. We also found that sandy substrates have lower morphospecies diversity than other substrates. There was a positive correlation between microhabitat diversity and morphospecies diversity within a quadrant. Our results suggest that microhabitats contribute to reef diversity in different ways. For instance, some have a higher density of morphospecies richness, while others contribute more unique morphospecies to reefs overall. Spatial heterogeneity also plays a key role. While heights and widths are poor indicators for biodiversity, the number of microhabitats present have a positive relationship with diversity. ( ,, )
Abstract:
Los microhábitats puede ser importantes para comprender el uso del hábitat a pequeña escala de las poblaciones marinas. Este estudio examina el papel de microhábitats, definido como una combinación de características del sustrato, así como la heterogeneidad espacial en la biodiversidad de los arrecifes rocosos frente a la costa de Cuajiniquil, Guanacaste, Costa Rica. Examinamos veinte cuadrantes en tres sitios, registrando las morfoespecies de animales bentónicos que observamos, los microhábitats que ocupaban y medimos las características físicas de cada hábitat. Las cuevas pedregosas albergaron más morfoespecies en un área determinada que otros microhábitats, y las planicies rocosas y las pozas pedregosas albergaron más morfoespecies únicas en total. También encontramos que los sustratos arenosos tienen una diversidad de morfoespecies más baja que otros sustratos. Hubo una correlación positiva entre la diversidad de microhábitats y la diversidad de morfoespecies dentro de un cuadrante. Nuestros resultados sugieren que los microhábitats contribuyen a la diversidad de los arrecifes de diferentes maneras. Por ejemplo, algunos tienen una mayor densidad de riqueza de morfoespecies, mientras que otros aportan morfoespecies más únicas a los arrecifes en general. La heterogeneidad espacial también juega un papel clave. Si bien las alturas y el ancho son indicadores deficientes para la biodiversidad, el número de microhábitats presentes tiene una relación positiva con la diversidad.
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Student affiliation: Department of Biology, Ecology, Behavior, and Evolution Section, University of California, San Diego; Department of Ecology and Evolutionary Biology and Department of Latin American Satino Studies, University of California, Santa Cruz.
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Hawkins & Medina 1 M icrohabitat influences morphospecies richness on Costa Rican rocky reefs Brooke Hawkins Department of Biology, Ecology, Behavior, and Evolution Section University of California, San Diego Eric Medina Department of Ecology and Evolutionary Biology & Department of Latin American Latino Studies University of California, Santa Cruz EAP Tropical Biology and Conservation Program, Fall 2017 1 5 December 2017 ABSTRACT Microhabitat can be important in understanding small scale habitat use of marine populations. This study examines the role of microha bitat, defined as a combination of substrate feature as well as spatial heterogeneity on the biodiversity of rocky reefs off the coast of Cuajiniquil, Guanacaste, Costa Rica. We surveyed twenty quadrats from three sites, recording the benthic animal morph ospecies we observed, the microhabitats they occupied, and measured physical attributes of each habitat. We found that stony caves harbor more morphospecies in a given area than other microhabitats, but that rocky flats and stony pools host more unique mor phospecies in total. We also found that sandy substrates have lower morphospecies diversity than other substrates. There was a positive correlation between microhabitat diversity and morphospecies diversity within a quadrant. Our results suggest that micro habitats contribute to reef diversity in different ways. For instance, some have a higher density of morphospecies richness, while others contribute more unique morphospecies to reefs overall Spatial heterogeneity also plays a key role. While h eights and widths are poor indicators for biodiversity, the number of microhabitats present have a positive relationship with diversity. EL microh‡bitat influye la riqueza de morfoespecies en arrecifes piedrosos costarricenses RESUMEN Los microh‡bitats puede ser importantes para comprender el uso del h‡bitat a peque–a escala de las poblaciones marinas. Este estudio examina el papel de microh‡bitats, definido como una combinaci—n de caracter’sticas del sustrato, as’ como la heterogeneidad es pacial en la biodiversidad de los arrecifes rocosos frente a la costa de Cuajiniquil, Guanacaste, Costa Rica. Examinamos veinte cuadrantes en tres sitios, registrando las morfoespecies de animales bent—nicos que observamos, los microh‡bitats que ocupaban y medimos las caracter’sticas f’sicas de cada h‡bitat. Las cuevas pedregosas albergaron m‡s morfoespecies en un ‡rea determinada que otros microh‡bitats, y las planicies rocosas y las pozas pedregosas albergaron m‡s morfoespecies œnicas en total. TambiŽn en contramos que los sustratos arenosos tienen una diversidad de morfoespecies m‡s baja que otros sustratos. Hubo una correlaci—n positiva entre la diversidad de microh‡bitats y la diversidad de morfoespecies dentro de un cuadrante. Nuestros

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Rocky Reef Microhabitat Hawkins & Medina 2 resultados sugier en que los microh‡bitats contribuyen a la diversidad de los arrecifes de diferentes maneras. Por ejemplo, algunos tienen una mayor densidad de riqueza de morfoespecies, mientras que otros aportan morfoespecies m‡s œnicas a los arrecifes en general. La hete rogeneidad espacial tambiŽn juega un papel clave. Si bien las alturas y el ancho son indicadores deficientes para la biodiversidad, el nœmero de microh‡bitats presentes tiene una relaci—n positiva con la diversidad Our understanding of marine habitats i s integral to addressing our world's largest issues such as food security, mass extinctions, and the effects of climate change. Reefs are important marine habitats that are defined as rigid structures near the surface of the water. They are economically im portant to coastal communities, acting as incubators for juvenile fish that later support commercial fisheries and for attracting e cotourism. Reefs are built on materials that vary from the bodies of ecosystem engineer species to the remains of geologic ev ents such as canyons and rock rubble (Graham et al 2013). These structures encourage diversity, and because of this reefs have become a focus for ecological investigation and conservation efforts. Reefs are diverse marine habitats because of the struct ural complexity they provide ( Crowder & Cooper 1982 Greenburg 2015). Structural complexity is important to a variety of ecosystems, including forests, seagra ss, and kelp beds (Graham et al. 2013). In reefs specifically, substrates such as coral, mollusk shells, and rocks are three dimensional structures that create microhabitats allowing for greater species diversity and abundance ( Crowder & Cooper 1982 ). Reefs are not homogen ous throughout and small scale characteristics such as substrates, like kelp cov er ( Levin 1991 ), and features, like coral branch sizes ( Kane et al. 2009 ), can be used to describe microhabitat. In past studies, microhabitat has been found to have significant implications for ecological processes such as fish recruitment and community d istribution (Levin 1991 ). In the past 50 years, literature about coral reef structural complexity has exponen tially increased (Graham et al. 2013) but it i s crucial to understand that coral reefs are not the only type of ecologically important reef. On the East Coast of the United States, reefs formally existed from generations of oyster shells piled on top of each other (Greenburg 2015) and on the Pacific Coast of Costa Rica, there are diverse communities being supported by rocky reefs ( Myers et al. 2 011, Phillips & Perez Cruet 1983 ). Our study aims to better understand the relationship that microhabitats have with the biodiversity observed along rocky reefs off the coast of Cuajiniquil, Guanacaste, Costa Rica. We consider biodiversity to be the coun t of benthic animal morphospecies distinguishable using the naked eye. We address two questions. First, what is the relationship between biodiversity and microhabitat? For this study, we define microhabitat as a combination of substrate and feature where s ubstrate is a surface that organisms live on, and a feature refers to the shape and orientation of a substrate. Structures that provide topographic complexity can better protect organisms from predation and are thus preferred (Wellington 1981). Because of this established understanding, we predicted that individual microhabitats that provide more protection, such as pools and caves, would foster significantly more diverse communities. Our second question is what is the relationship between biodiversity and small scale spatial heterogeneity? We used the

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Rocky Reef Microhabitat Hawkins & Medina 3 variation found in heights and widths of features to determine spatial heterogeneity for this project. We predicted that areas that are more spatially heterogeneous would also have higher diversity. By develo ping our understanding of microhabitats found in rocky reefs and their implications for biodiversity, we can learn about the most ecologically significant structures for maintaining diverse reefs. In the future, this knowledge can be used to inform efforts in reef restoration, conservation, and population mapping. MATERIALS AND METHODS Overview For this study, we defined microhabitat as a combination of substrate (Table 1) and feature ( Table 2 ). We defined substrate as a non living surface that organisms were observed living on, and we describe d feature as the shape and orientation of a substrate We surveyed twenty quadrats in seven sampling sessions with one to four quadrats surveyed per session We collected data from 18 November 2017 to 24 N ovember 2017 at three different sites around Cuajiniquil: La Islita, Bajo Rojo, and Isla David. We randomly selected 30 cm x 30 cm quadrat s along a 20 meter transect parallel to shore, at a depth within our snorkeling limits. In each quadrat, we recorded information about the microhabitat s spatial heterogeneity, and benthic animal morphospecies observed. We described each morphospecies and documented their presence and absence in each microhabitat. Table 1. Substrates obse rved with corresponding code, description, and sample size. A substrate is a non living surface we observed organisms living on The substrate code is used in the x axis of Figure 2 The sample size is the number of quadrats which contained the given feature. Substrate Code Description Sample Size Rock R Rocky bottom N = 11 Sand S Sandy bottom N = 9 Stone P Detached rock sitting on top of another substrate N = 12 Wood O Sunken log N = 1 Table 2 Features observed with corresponding code, description, and sample size. A feature is the shape and orientation of a substrate The feature code is used in the x axis of Figure 3 The sample size is the number of quadrats which contained the given feature. Feature Code Description Sample Size Flat F Mostly flat area N = 18 Crack C Space of one substrate bet ween different substrate(s) Example: sand between two stones N = 14 Cave V Vertical divot N = 8

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Rocky Reef Microhabitat Hawkins & Medina 4 Pool P Horizontal divot N = 12 Shelf S Area beneath an overhanging rock or stone N = 3 Edge E Side of rock or stone N = 1 Microhabitat We recorded the benthic animal morphospecies in each quadra t with the naked eye We inspected the substrate s and feature s within the quadrat, recorded every morphospecies observed and noted what substrate (s) and feature (s) each morphospecies occupied. To ensure each quadrat was observed thoroughly, we continued surveying a quadrat until we found no new morphospecies for two consecutive free div es. In order to answer our question about the relationship between microhabitat and biodiversity, we calculated the mean number of morphospecies per m icrohabitat within each quadrat and compared the averages across microhabitats using a box and whisker plo t. Statistical significance was determined using a one way ANOVA in R. We plotted all microhabitat categories, but any category with a sample size of less than three was excluded from the one way ANOVA. We then repeated this analysis for substrates and for features independently. Spatial Heterogeneity We recorded data on the physical attributes of microhabitats In each quadra t, we took ten random measure ments ( five heights and five widths ) using a measuring tape We chose heights to measure by drawing an imaginary X in the center of the quadrat, and measuring features at the center and the four corners of the X. To choose widths, we drew another imaginary X at a 45 degree angle from the first and measured features at the center and four cor ners of that X. We used the range in measurements, the maximum minus the minimum, with in a quadrat as a measure of spatial heterogeneity. We graphed morphospecies richness against measurement ranges on a scatterplot, and tested the statistical significance of the correlation by calculating Pearson's coefficient of correlation in R. We then repeated the analysis, this time comparing morphospecies richness against the microhabitat richness found in each quadrat. RESULTS Overview In the quadrats we surveyed, w e observed a total of 3 1 different morphospecies (Table 3 ) and 14 different microhabitats ( Table 4 ). We recorded which microhabitat(s) each morphospecies occupied (Table 5), and determined the unique number of morphospecies found in each microha bitat (List 1). Table 3. Every observed morphospecies with description. Morphospecies Description Barnacle A Small, white, and in large quantities when found. Grows on flat surfaces. Barnacle B Larger than Barnacle A. Found in caves and in lower

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Rocky Reef Microhabitat Hawkins & Medina 5 quantities than Barnacle A. Does not aggregate. Bivalve A Common in intertidal zone. About the size of a quarter. Dark colored and often has plants growing on it. Bivalve B Bivalve found in caves and with a smooth light colored shell. Bivalve C Has fleshy structure that ret reats into shell when touched. Black and White Brittle Star Usually smaller than Black Brittle Star. Most of body is black with white stripes along tentacles. Black Brittle Star Entire body is black One of the two most common organisms we observed Has black bristles coming off of tentacles and usually lighter on the underside. Black Urchin The most common urchin found in the reefs we surveyed. Blue Bell Tunicate Commonly found attached to flat surfaces on rocks. Brightly c olored sedentary invertebrates that often grow together. Blue Chromis Brightly colored small fish. Often protecting a den. Branched Fan Worm A Red and with thicker branches than B & C. When agitate d retreats like a feather duster worm or s ea a nemone. Has fleshy branches that look like algae but retreat s into a tube structure when touched. Branched Fan Worm B Gray. When agitated, retreats like a feather duster worm or s ea a nemone. Has fleshy branches that look like algae but retreat s into a tube struct ure when touched. Branched Fan Worm C Black. When agitated, retreats like a feather duster worm or s ea a nemone. Has fleshy branches that look like algae but retreat s into a tube structure when touched. Chiton Flat mollusk that is common throughout our sites. Identified by i ts oval, flat shape and a hole on the top of its shell facing upward. Circular Mol l usk Observed several times, but only once in quadrat. Often flat on a substrate and has a shell that curves around the body but remains flat against substrate. Thin shell often different shades of brown. Blends in very well. Crustacean A Thin body with many legs. A dark brown color. Crustacean B Colored red with white spots along body. Observed feeding often. Appears to be a type of cleaning shrim p. Feather Duster Worm Sedentary worm that creates tube and uses fan structure to filter feed. We've seen many colors, but classify them into one morphospecies. Gastropod A Snail living in rocky caves, and flat surfaces of rocks. Reddish brown color with white dots along shell. Shell has rough texture. Gastropod B Smaller pink snail with smooth shell. Gastropod C Much larger than Gastropod A and B. Has a dark pink and re d brown splotched shell. Relatively smooth.

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Rocky Reef Microhabitat Hawkins & Medina 6 Hancock's Tube Blenny Tube blenny with large red eyes and a green blue body. Has distinct brown patches on body. Limpet Dark shelled mollusk that sticks to flat surfaces. Pencil Urchin Solitary urchin with visibly white star on body. Has low quantity of dull thick spines. Purple and White Urchin Seen once, has white and purple spots along spines. Red and White Brittle Star Observed once in Islita. Red and white coloration on tentacles. Red Head Goby Benthic fish often found sitting on the surface of a substrate. Red eyes and clear body. Sand Colored Goby Small fish that blends in well with substrate. Usually f ound siting on flat surface of substrate. Sea Anemone A Dull colored and very common especially in Islita. Often covers entire substrates. Has fleshy brown or gray tentacles. Sea Anemone C Small body with long white tentacles. Table 4 Microhabitats observed with corresponding code and sample size Each mi crohabitat is a unique combination of substrate and feature. Note that not all possible combinations of substrate and feature were observed. The microhabitat code is used in the x axis of Figure 1. The sample size is the number of quadrats which contained the microhabitat. Observed Microhabitat Microhabitat Code Sample Size Rocky Flat RF N = 10 Rocky Crack RC N = 5 Rocky Cave RV N = 5 Rocky Pool RP N = 7 Rocky Shelf RS N = 2 Sandy Flat SF N = 2 Sandy Crack SC N = 8 Sandy Shelf SS N = 1 Stony Flat PF N = 1 0 Stony Crack PC N = 5 Stony Cave PV N = 4 Stony Pool PP N = 6 Stony Edge PE N = 1

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Rocky Reef Microhabitat Hawkins & Medina 7 Wooden Flat OF N = 1 Table 5. Data collected on morphospecies presence and absence by microhabitat See microhabitat codes in Table 3. Zero indicates absence, one indicates presence. Microhabitat Morpho species RF RC RV RP RS SF SC SS PF PC PV PP PE OF Barnacle A 1 0 0 0 0 0 0 0 0 0 0 0 0 0 Barnacle B 1 1 0 1 0 0 0 0 0 0 0 0 0 0 Bivalve A 1 0 0 0 0 0 0 0 0 0 0 0 0 0 Bivalve B 1 0 1 0 0 0 0 0 0 0 0 1 0 0 Bivalve C 0 0 0 0 0 0 0 0 0 0 0 1 0 0 Black and White Brittle Star 0 0 1 1 0 0 1 0 0 1 1 1 0 0 Black Brittle Star 0 1 0 1 0 0 1 0 0 1 1 0 0 0 Black Urchin 0 1 1 1 0 1 1 0 0 1 1 0 0 0 Blue Bell Tunicate 1 0 0 0 0 0 0 0 1 0 0 1 1 0 Blue Chromis 0 0 0 0 0 0 0 0 0 0 0 1 0 0 Branched Fan Worm A 0 0 0 0 0 0 0 0 0 0 0 1 0 0 Branched Fan Worm B 0 0 0 0 0 0 0 0 0 1 1 0 0 0 Branched Fan Worm C 0 0 0 0 0 0 0 0 0 1 1 0 0 0 Chiton 1 1 0 0 0 0 0 0 1 0 0 0 0 0 Circular Mo l lusk 1 0 0 0 0 0 0 0 0 0 0 0 0 0 Crustacean A 0 1 0 0 0 0 0 0 0 0 0 0 0 0 Crustacean B 0 0 0 0 0 0 0 0 0 0 1 0 0 0 Feather Duster Worm 1 1 1 1 1 1 1 0 0 1 0 1 0 0

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Rocky Reef Microhabitat Hawkins & Medina 8 Gastropod A 1 0 1 0 0 0 1 0 1 0 0 0 0 0 Gastropod B 1 0 0 0 0 0 0 0 1 1 0 0 0 0 Gastropod C 0 0 0 0 1 0 0 0 0 0 0 0 0 0 Hancock's Tube Blenny 1 0 0 0 0 0 0 0 0 0 0 1 0 0 Limpet 1 0 0 0 0 0 0 0 1 0 1 1 0 0 Pencil Urchin 0 0 0 0 0 0 1 0 0 0 1 0 0 0 Purple and White Urchin 0 0 1 0 0 0 0 0 0 0 0 0 0 0 Red and White Brittle Star 0 0 0 1 0 0 0 0 0 0 0 0 0 0 Red Head Goby 0 1 1 1 0 0 0 0 0 0 1 1 0 0 Sand Colored Goby 1 0 1 0 0 0 0 1 1 0 0 1 0 1 Sea Anemone A 1 1 1 1 0 0 0 0 1 0 1 1 0 0 Sea Anemone B 0 1 0 1 0 0 1 0 1 1 0 0 1 0 Sea Anemone C 0 0 0 0 0 0 0 0 1 0 0 0 0 0 List 1 List of microhabitats that have unique morphospecies, organized alphabetically by microhabitat. Refer to Table 3 for microhabitat code. The number in parentheses indicates the number of morphospecies u nique to that given microhabitat The following morphospecies are those unique to that microha bitat. Note that not all microhabitats are included, because not all microhabitats contain unique morpho species. RF (3): Barnacle A, Bivalve A, Circular Mol l usk RC (1): Crustacean A RV (1): Purple and White Urchin RP (1): Red and White Brittle Star RS (1): Gastropod C PF (1): Sea Anemone C PV (1): Crustacean B

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Rocky Reef Microhabitat Hawkins & Medina 9 PP (3): Bivalve C, Blue Chromis, Branched Fan Worm A Microhabitat Morphospecies richness varie d with microhabitat (Figure 1). Only one microhabitat, stony caves, emerged with significantly higher morphospecies richness than the others (one way ANOVA, p = 0.033 ). We also evaluated morphospecies richness against substrate (Figure 2) and feature (Figure 3). Sandy substrates had significantly lower morphospecies richness than rocky or stony subs trates (one way ANOVA, p = 0.004 ). T here were no significant differences between features ( one way ANOVA p = 0.1 4 2 ). Figure 1 Morphospecies richness plotted by microhabitat. Morphospecies richness is counted as the number of morphospecies seen in a mi crohabitat per quadrat. We defined microhabitat as a unique combination of substrate and feature. The first letter of the microhabitat code refers to

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Rocky Reef Microhabitat Hawkins & Medina 10 substrate, and the second refers to feature. S ee Table 4 for microhabitat codes on x axis and correspondin g sample sizes. Empty circles denote outliers. Figure 2. Morphospecies richness plotted by substrate. Morphospecies richness is counted as the number of morphospecies seen in a substrate per quadrat. We defined substrate as a non living surface we observed organisms living on See Table 1 for substrate codes on x axis and corresponding sample sizes. Empty circles denote outliers. Figure 3. Morphospecies richness plotted by feature. Morphospecies richness is counted as the number of morphospeci es seen in a feature per quadrat. We defined feature as the shape and

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Rocky Reef Microhabitat Hawkins & Medina 11 orientation of the substrate See Table 2 for feature codes on x axis and corresponding sample sizes. Empty circles denote outliers. Spatial Heterogeneity We investigated the correlation between mo rphospecies richness and range in height and width measurements for each quadrat (Figure 4), and found no significant relationship ( correlation coefficient = 0. 111 p = 0. 638 ). However, there was a p ositive correlation between morphos pecies richness and microhabitat richness in a quadrat ( Figure 5 ) that is statistically significant (correlation coefficient = 0. 563 p = 0. 009 ). Figure 4 Morphospecies r ichness plotted against range of measurement by quadrat. Morphospecies richness is counted as the number of morphospecies seen in a quadrat. The range of measurements was calculated by subtracting the minimum measurement from the maximum measurement of heights and widths in each quadrat. Heights and widths are not distinguished in this calculation. Each point represents one quadrat (N=20).

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Rocky Reef Microhabitat Hawkins & Medina 12 Figure 5 Morphospecies richness plotted against microhabitat richness by quadrat Each point represents one quadrat (N=20). DISCUSSION Microhabitat This study furthers our understanding of the ecological implications of microhabitats in rocky reefs. We are concerned with what combinations of substrate and feature may have influence on the diversity found in rocky reefs. We found that stony cave microhabitats have a highe r diversity of morphospecies than other micr ohabitats (Figure 1). There was one organism found only in this microhabitat (List 1), and three organisms found in this microhabitat that only appear in stony c aves and one other microhabitat (Table 5). This sug gests that stony caves, in our samples, are not acting simply as habitat for a high number of morph o species, but are in fact attracting unique morphospecies that do not app ear in other microhabitats. T his relationship suggest s that the characteristics of s tony caves have influence on the diversity of benthic animals found in reefs. This corroborates past studies that find reef organism s prefer habitats that offer more protection (Wellington 1981). It is important to consider that even though there is a si gnificant difference between stony caves and other microhabitats this does not necessarily mean that they are of more importance to rocky reefs. This simply tells us that this microhabitat encourages a higher density of unique morphospecies. In fact, othe r microhabitats contained a higher number of unique morphospecies; r ocky flat s and stony pool s each had three unique morphospecies. This suggests tha t they too

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Rocky Reef Microhabitat Hawkins & Medina 13 play important roles for benthic animal diversity in rocky reefs but simply do no t have the gre atest density of unique species in a given area It is also worth considering that this study is li mited by its small sample size. I n total we had 139 observations that were broken down into 14 different microhabitats. This breaks down our sample size to an average of approximately 10 observations per microhabitat leaving our findings susceptible to non representative samples and skewed trends. We also found that substrate corresponds to biodiversity: sandy substrates have significantly fewer morphospecies than rocky and stony substrates (Figure 2). There was no trend between any specific feature and morphospecies richness (Figure 3). Our findings suggest that rock and stone create structures that promote morphospecies richness that exists in r ocky reefs. This corroborates past studies that have established the importance of structural complexity ( Graham et al. 2013 ). Our results also suggest that no singular feature contributes more to morphospecies richness than other features do. Beyond this, our findings contribute to the existing literature about microhabitats in rocky reefs. It suggests that substrate influences the ecological processes we observe and are thus a useful consideration for future s tudies looking at microhabitat and benthic ani mal diversity in rocky reefs. Spatial Heterogeneity We did not find the predicted positive correlation between measurement ranges and microhabitat diversity (Figure 4). The lack of a trend between these two factors indicates that height and width measurem ents of random features are poor indicators of morphospecies diversity within a given microhabitat. Instead, we found that the combination of microhabitats found within quadrat s played a role in biodiversity. We detected a trend that diversity increased wi th the number of microhabitats present in quadrat s ( Figure 5 ). The significance of this finding is a better understanding of the mechanism spatial heterogeneity has for creating more diverse reefs. Initially we hypothesize d that an increase in spatial het erogeneity would promote diversity, but this was in regard to heights and widths of features such as rock edges and pool depths not the manner in which features were shaped. This may suggest that we must begin thinking of heterogeneity in different terms. Our findings emphasize the importance of contextualizing microhabitats. Perhaps there is no specific combination of characteristics that promote biodiversity, but it is the quantity of combinations that exist in a space that will lead to healthy reefs. I mplications Literature concerning the importance of microhabitat is often specifically looking at how one species interacts with a habitat (Levin 1991, Hegazy et al. 2007) Our study deviates from previous literature about microhabitats because we are trying to understand the e ffect s microhabitat may have on a wider community of benthic organisms as opposed to focusing on one species W e gained insights for determining benthic animal diversity in rocky reef microhabitats. We identified one specific microhabitat and one particular substrate that significantly influenced biodiversity and found that feature may not hav e a relationship with diversity. This is a starting point for understanding the mechanism s at play in structurally complex habitats. We have learned that heterogeneity in habitat goes beyond our measurements of heights and widths of

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Rocky Reef Microhabitat Hawkins & Medina 14 features and perhaps looking at microhabitats in context with surrounding microhabitats will prove fruitful for determining benthic animal diver sity in rocky reefs. ACKNOWLEDGEMENTS We would like to thank Frank Joyce and SofÂ’a Arce Flores for their guidance throughout our project and time in Costa Rica. Thank you Minor and Lara family for all of the support you provided us while in Cuajiniquil. Thank you to our wonderful classmates that supported us throughout the data collection process: Rebecca Ash, Zac hary Durall, Nathan Howell, Stephanie Li, Jennay Argiris, John LaBonte, and Eliot Headley. Thanks also goes to Kathy Dao and Georgia Van Tyne for their helpful feedback on this paper. Thanks again to SofÂ’a for helping us translate. Finally, thank you to Flor Lara and t o t he Castro Campos family for warmly housing us during our stay in Cuajiniquil. LITERATURE CITED Crowder LB, and WE Cooper. 1 982. Habitat structural complexity and the interaction between bluegills and their prey. Ecology 63: 1802 1813 Graham, N.A.J. and K.L. Nash. 2013. The importance of structural comp lexity in coral reef ecosystems Coral Reefs 32: 315 326. Greenberg, Paul. 2015. "Oysters." American Catch: The Fight for Our Local Seafood The Penguin Press. Hegazy, Ahmad K. and Hanan F. Kabiel. 2007. Significance of microhabitat heterogeneity in the spatial pattern and size class structure of Anastatica hierochuntica L. Ac ta Oecologica 31: 332 342. Kane, Corinne N. Andrew J. Brooks Sally J. Holbrook, and Russell J. Schmitt. 2009. The role of microhabitat preference and social organization in determining the spatial distribution of a coral reef fish Environ Biol Fish 84: 1. Levin, Phillip S. 1991. Effects of microhabitat on recruitment variatio n in a Gulf of Maine reef fish Marine Ecology Progress Series 75 : 183 189. Myers, Mark C., Jonathan W agner, and Christopher Vaughan. 2011. Long term comparison of the fish community in a Costa Rican rocky shore marine reserve. Rev. Biol. Trop. 59: 233 246. Phillips, Peter C., and Mikie J. Perez Cruet. 1983. A comparative survey of reef fishes in Caribbean and Pacific Costa Rica. Revista de Biologica Tropical X: XX XXX. Wellington, Gerar d M. 198 2 Depth Zonation of Corals in the Gulf of Pa nama: Control and Facilitation by Resident Reef Fish Ecological Monographs 52: 223 241. APPENDIX Data Table 6 Data collected on benthic animal morphospecies. Sample is unique identifier for each quadrat. Date is in dd mon format. Quadrat indicates quadrat location in meters along 20 m

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Rocky Reef Microhabitat Hawkins & Medina 15 transect Quadrat order is used in Figure 6 to evaluate a possible observation b ias. Quadrat order has the following values: F = first, M = middle, L = last, NI = not included. Depth is measured in centimeters. See substrate codes in Table 1. See feature codes in Table 2. Sample Date Site Quadrat Quadrat Order Depth Morphospecies Substrate Code Feature Code 1 18 Nov Islita 1 NI 249.4 Blue Bell Tunicate R F 1 18 Nov Islita 1 NI 249.4 Black Brittle Star R C 1 18 Nov Islita 1 NI 249.4 Black Urchin R V 1 18 Nov Islita 1 NI 249.4 Gastropod A R V 1 18 Nov Islita 1 NI 249.4 Feather Duster Worm S F 1 18 Nov Islita 1 NI 249.4 Sea Anemone A R F 1 18 Nov Islita 1 NI 249.4 Sea Anemone A R P 1 18 Nov Islita 1 NI 249.4 Sea Anemone A R C 2 18 Nov Isla David 25 F 134.4 Gastropod A R F 2 18 Nov Isla David 25 F 134.4 Bivalve A R F 2 18 Nov Isla David 25 F 134.4 Barnacle A R F 2 18 Nov Isla David 25 F 134.4 Barnacle B R F 2 18 Nov Isla David 25 F 134.4 Chiton R F 3 18 Nov Isla David 22 L 138 Black Urchin R P 3 18 Nov Isla David 22 L 138 Black Urchin R C 3 18 Nov Isla David 22 L 138 Sea Anemone A R C 3 18 Nov Isla David 22 L 138 Sea Anemone A R P 3 1 8 Nov Isla David 22 L 138 Sea Anemone B R C 3 18 Nov Isla David 22 L 138 Sea Anemone B R P 3 18 Nov Isla David 22 L 138 Bivalve B R F

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Rocky Reef Microhabitat Hawkins & Medina 16 3 18 Nov Isla David 22 L 138 Barnacle A R F 3 18 Nov Isla David 22 L 138 Chiton R C 3 18 Nov Isla David 22 L 138 Black Brittle Star R C 3 18 Nov Isla David 22 L 138 Black Brittle Star R P 3 18 Nov Isla David 22 L 138 Feather Duster Worm R C 3 18 Nov Isla David 22 L 138 Feather Duster Worm R P 3 18 Nov Isla David 22 L 138 Barnacle B R C 3 18 Nov Isla David 22 L 138 Barnacle B R P 4 19 Nov Islita 3 F 236.5 Black Urchin R P 4 19 Nov Islita 3 F 236.5 Red Head Goby R C 4 19 Nov Islita 3 F 236.5 Red Head Goby R P 4 19 Nov Islita 3 F 236.5 Sea Anemone A R C 4 19 Nov Islita 3 F 236.5 Feather Duster Worm R F 4 19 Nov Islita 3 F 236.5 Red and White Brittle Star R P 4 19 Nov Islita 3 F 236.5 Bivalve A R F 4 19 Nov Islita 3 F 236.5 Gastropod A R F 4 19 Nov Islita 3 F 236.5 Gastropod B R F 5 19 Nov Islita 12 M 280 Black Urchin R P 5 19 Nov Islita 12 M 280 Feather Duster Worm R S 5 19 Nov Islita 12 M 280 Blue Bell Tunicate R F 5 19 Nov Islita 12 M 280 Red Head Goby R V 5 19 Nov Islita 12 M 280 Sand Colored Goby R V 6 19 Nov Islita 15 M 358 Sea Anemone A R F

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Rocky Reef Microhabitat Hawkins & Medina 17 6 19 Nov Islita 15 M 358 Limpet R F 6 19 Nov Islita 15 M 358 Feather Duster Worm R P 7 19 Nov Islita 18 L 421 Sand Colored Goby R F 7 19 Nov Islita 18 L 421 Black Urchin R P 7 19 Nov Islita 18 L 421 Limpet R F 8 20 Nov Bajo Rojo 3 F 201.3 Limpet P F 8 20 Nov Bajo Rojo 3 F 201.3 Sand Colored Goby P F 9 20 Nov Bajo Rojo 10 M 192.3 Red Head Goby R V 9 20 Nov Bajo Rojo 10 M 192.3 Crustacean A R C 9 20 Nov Bajo Rojo 10 M 192.3 Black Urchin R C 9 20 Nov Bajo Rojo 10 M 192.3 Sea Anemone A R V 9 20 Nov Bajo Rojo 10 M 192.3 Gastropod B R F 9 20 Nov Bajo Rojo 10 M 192.3 Bivalve B R V 9 20 Nov Bajo Rojo 10 M 192.3 Limpet R F 10 20 Nov Bajo Rojo 12 M 226.3 Pencil Urchin S C 10 20 Nov Bajo Rojo 12 M 226.3 Limpet P P 10 20 Nov Bajo Rojo 12 M 226.3 Bivalve B P P 10 20 Nov Bajo Rojo 12 M 226.3 Black Brittle Star P C 10 20 Nov Bajo Rojo 12 M 226.3 Hancock's Tube Blenny P P 11 20 Nov Bajo Rojo 18 L 221 Limpet P F 11 20 Nov Bajo Rojo 18 L 221 Limpet P V 11 20 Nov Bajo Rojo 18 L 221 Purple and White Urchin R V 11 20 Nov Bajo Rojo 18 L 221 Feather Duster Worm R F

PAGE 18

Rocky Reef Microhabitat Hawkins & Medina 18 11 20 Nov Bajo Rojo 18 L 221 Circular Molusk R F 11 20 Nov Bajo Rojo 18 L 221 Black Brittle Star R P 11 20 Nov Bajo Rojo 18 L 221 Black and White Brittle Star R P 11 20 Nov Bajo Rojo 18 L 221 Blue Bell Tunicate P P 11 20 Nov Bajo Rojo 18 L 221 Black Urchin P V 11 20 Nov Bajo Rojo 18 L 221 Hancock's Tube Blenny R F 12 22 Nov Bajo Rojo 3 F 291 Sea Anemone A P V 12 22 Nov Bajo Rojo 3 F 291 Limpet P F 12 22 Nov Bajo Rojo 3 F 291 Branched Fan Worm A P P 12 22 Nov Bajo Rojo 3 F 291 Bivalve C P P 12 22 Nov Bajo Rojo 3 F 291 Black Urchin S C 12 22 Nov Bajo Rojo 3 F 291 Blue Bell Tunicate P F 12 22 Nov Bajo Rojo 3 F 291 Crustacean B P V 12 22 Nov Bajo Rojo 3 F 291 Black and White Brittle Star P V 12 22 Nov Bajo Rojo 3 F 291 Black and White Brittle Star P P 12 22 Nov Bajo Rojo 3 F 291 Feather Duster Worm P P 12 2 2 Nov Bajo Rojo 3 F 291 Pencil Urchin P V 13 22 Nov Bajo Rojo 7 L 329.5 Black and White Brittle Star P V 13 22 Nov Bajo Rojo 7 L 329.5 Black Urchin S F 13 22 Nov Bajo Rojo 7 L 329.5 Black Urchin S C 13 22 Nov Bajo Rojo 7 L 329.5 Limpet P F

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Rocky Reef Microhabitat Hawkins & Medina 19 13 22 Nov Bajo Rojo 7 L 329.5 Sea Anemone A P V 13 22 Nov Bajo Rojo 7 L 329.5 Sea Anemone A P P 13 22 Nov Bajo Rojo 7 L 329.5 Branched Fan Worm C P C 13 22 Nov Bajo Rojo 7 L 329.5 Branched Fan Worm C P V 13 22 Nov Bajo Rojo 7 L 329.5 Branched Fan Worm B P C 13 22 Nov Bajo Rojo 7 L 329.5 Branched Fan Worm B P V 14 23 Nov Islita 3 F 347.4 Sand Colored Goby O F 14 23 Nov Islita 3 F 347.4 Sea Anemone B P F 14 23 Nov Islita 3 F 347.4 Sea Anemone B P E 14 23 Nov Islita 3 F 347.4 Sea Anemone C P F 14 23 Nov Islita 3 F 347.4 Blue Bell Tunicate P F 14 23 Nov Islita 3 F 347.4 Blue Bell Tunicate P E 14 23 Nov Islita 3 F 347.4 Feather Duster Worm R F 14 23 Nov Islita 3 F 347.4 Gastropod A S C 15 23 Nov Islita 11 M 318.3 Black and White Brittle Star S C 15 23 Nov Islita 11 M 318.3 Blue Bell Tunicate P F 15 23 Nov Islita 11 M 318.3 Sea Anenome A P F 15 23 Nov Islita 11 M 318.3 Feather Duster Worm P C 15 23 Nov Islita 11 M 318.3 Feather Duster Worm S C 15 23 Nov Islita 11 M 318.3 Sand Colored Goby S S 16 23 Nov Islita 12 M 321.4 Sea Anemone B P F 16 23 Nov Islita 12 M 321.4 Sea Anemone C P F

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Rocky Reef Microhabitat Hawkins & Medina 20 16 23 Nov Islita 12 M 321.4 Feather Duster Worm S C 17 23 Nov Islita 16 L 309 Sea Anemone B P F 17 23 Nov Islita 16 L 309 Sea Anemone B P C 17 23 Nov Islita 16 L 309 Sea Anemone B S C 17 23 Nov Islita 16 L 309 Sea Anemone C P F 17 23 Nov Islita 16 L 309 Blue Bell Tunicate P F 17 23 Nov Islita 16 L 309 Black Brittle Star S C 17 23 Nov Islita 16 L 309 Feather Duster Worm S C 18 24 Nov Bajo Rojo 2 F 228.5 Blue Chromis P P 18 24 Nov Bajo Rojo 2 F 228.5 Sand Colored Goby P P 18 24 Nov Bajo Rojo 2 F 228.5 Red Head Goby P P 18 24 Nov Bajo Rojo 2 F 228.5 Gastropod C R S 18 24 Nov Bajo Rojo 2 F 228.5 Black Urchin R C 18 24 Nov Bajo Rojo 2 F 228.5 Black Urchin R V 18 24 Nov Bajo Rojo 2 F 228.5 Feather Duster Worm R V 18 24 Nov Bajo Rojo 2 F 228.5 Black and White Brittle Star R V 18 24 Nov Bajo Rojo 2 F 228.5 Bivalve B R V 19 24 Nov Bajo Rojo 8 M 218.5 Red Head Goby P V 19 24 Nov Bajo Rojo 8 M 218.5 Black Brittle Star P V 19 24 Nov Bajo Rojo 8 M 218.5 Gastropod A P F 19 24 Nov Bajo Rojo 8 M 218.5 Gastropod A S C 19 24 Nov Bajo Rojo 8 M 218.5 Sea Anemone B P F

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Rocky Reef Microhabitat Hawkins & Medina 21 19 24 Nov Bajo Rojo 8 M 218.5 Pencil Urchin P V 19 24 Nov Bajo Rojo 8 M 218.5 Crustacean B P V 20 24 Nov Bajo Rojo 11 L 187.7 Chiton P F 20 24 Nov Bajo Rojo 11 L 187.7 Gastropod B P F 20 24 Nov Bajo Rojo 11 L 187.7 Gastropod B P C 20 24 Nov Bajo Rojo 11 L 187.7 Black Urchin P C 20 24 Nov Bajo Rojo 11 L 187.7 Black and White Brittle Star P C 20 24 Nov Bajo Rojo 11 L 187.7 Branched Fan Worm A P P Table 7 Data collected on microhabitat spatial heterogeneity Sample is unique identifier for each quadrat. Date is in dd mon format. Quadrat indicates quadrat location in meters along 20 m transect Depth is measured in centimeters. See substrate codes in Table 1. See feature code s in Table 2. Type indicates if measurement is height or width, and has the following values: H = height, W = width. Measure is the measurement of the feature in centimeters. Sample Date Site Quadrat Depth Substrate Code Feature Code Type Measure 1 18 Nov Islita 1 249.4 R E H 52 1 18 Nov Islita 1 249.4 R E H 21 1 18 Nov Islita 1 249.4 R E H 32 1 18 Nov Islita 1 249.4 R E H 22 1 18 Nov Islita 1 249.4 S C W 4.5 1 18 Nov Islita 1 249.4 S C W 2.3 1 18 Nov Islita 1 249.4 S C W 4.3 1 18 Nov Islita 1 249.4 S C W 1.6 1 18 Nov Islita 1 249.4 S C W 2.3 2 18 Nov Isla David 25 134.4 R P H 9.2 2 18 Nov Isla David 25 134.4 R P H 7.4 2 18 Nov Isla David 25 134.4 R P H 5.1 2 18 Nov Isla David 25 134.4 R P H 4.7

PAGE 22

Rocky Reef Microhabitat Hawkins & Medina 22 2 18 Nov Isla David 25 134.4 R E H 6.7 2 18 Nov Isla David 25 134.4 R P W 1.3 2 18 Nov Isla David 25 134.4 R P W 0.3 2 18 Nov Isla David 25 134.4 R P W 2 2 18 Nov Isla David 25 134.4 R P W 1.3 2 18 Nov Isla David 25 134.4 R P W 2.2 3 18 Nov Isla David 22 138 R E H 6.8 3 18 Nov Isla David 22 138 R P H 1.9 3 18 Nov Isla David 22 138 R P H 5 3 18 Nov Isla David 22 138 R P H 6.7 3 18 Nov Isla David 22 138 R P H 5.4 3 18 Nov Isla David 22 138 R P W 6.7 3 18 Nov Isla David 22 138 R P W 3.9 3 18 Nov Isla David 22 138 R P W 4.1 3 18 Nov Isla David 22 138 R P W 4.5 3 18 Nov Isla David 22 138 R P W 2.8 4 19 Nov Islita 3 236.5 R P H 4.6 4 19 Nov Islita 3 236.5 R P H 5.3 4 19 Nov Islita 3 236.5 R P H 0.4 4 19 Nov Islita 3 236.5 R P H 10.1 4 19 Nov Islita 3 236.5 R P H 1.4 4 19 Nov Islita 3 236.5 R P W 4.1 4 19 Nov Islita 3 236.5 R P W 3.5 4 19 Nov Islita 3 236.5 R P W 2.6 4 19 Nov Islita 3 236.5 R P W 2.8 4 19 Nov Islita 3 236.5 R P W 5.6 5 19 Nov Islita 12 280 R E H 3.7

PAGE 23

Rocky Reef Microhabitat Hawkins & Medina 23 5 19 Nov Islita 12 280 R P H 2.8 5 19 Nov Islita 12 280 R P H 6.8 5 19 Nov Islita 12 280 R P H 6.7 5 19 Nov Islita 12 280 R P H 4.3 5 19 Nov Islita 12 280 R P W 5.2 5 19 Nov Islita 12 280 R P W 4.8 5 19 Nov Islita 12 280 R P W 7.5 5 19 Nov Islita 12 280 R P W 2.4 5 19 Nov Islita 12 280 R V W 7.6 6 19 Nov Islita 15 358 R P H 2.1 6 19 Nov Islita 15 358 R P H 3.3 6 19 Nov Islita 15 358 R P H 2.2 6 19 Nov Islita 15 358 R P H 1.8 6 19 Nov Islita 15 358 R P H 2.6 6 19 Nov Islita 15 358 R P W 6.4 6 19 Nov Islita 15 358 R P W 2.3 6 19 Nov Islita 15 358 R P W 5.3 6 19 Nov Islita 15 358 R P W 2.4 6 19 Nov Islita 15 358 R P W 1.9 7 19 Nov Islita 18 421 R F H 0 7 19 Nov Islita 18 421 R F H 0 7 19 Nov Islita 18 421 R F H 0 7 19 Nov Islita 18 421 R F H 0 7 19 Nov Islita 18 421 R F H 0 7 19 Nov Islita 18 421 R F W 0 7 19 Nov Islita 18 421 R F W 0 7 19 Nov Islita 18 421 R F W 0 7 19 Nov Islita 18 421 R F W 0 7 19 Nov Islita 18 421 R F W 0 8 20 Nov Bajo Rojo 3 201.3 P E H 5.4 8 20 Nov Bajo Rojo 3 201.3 P E H 9.3 8 20 Nov Bajo Rojo 3 201.3 P E H 11.2 8 20 Nov Bajo Rojo 3 201.3 P E H 5.6 8 20 Nov Bajo Rojo 3 201.3 P E H 4.2 8 20 Nov Bajo Rojo 3 201.3 S C W 2.5

PAGE 24

Rocky Reef Microhabitat Hawkins & Medina 24 8 20 Nov Bajo Rojo 3 201.3 S C W 2.2 8 20 Nov Bajo Rojo 3 201.3 S C W 1.9 8 20 Nov Bajo Rojo 3 201.3 S C W 2.2 8 20 Nov Bajo Rojo 3 201.3 S C W 1.1 9 20 Nov Bajo Rojo 10 192.3 R V H 5.3 9 20 Nov Bajo Rojo 10 192.3 R V H 7.9 9 20 Nov Bajo Rojo 10 192.3 R V H 4.4 9 20 Nov Bajo Rojo 10 192.3 R V H 8.6 9 20 Nov Bajo Rojo 10 192.3 R V H 6.2 9 20 Nov Bajo Rojo 10 192.3 R V W 5.6 9 20 Nov Bajo Rojo 10 192.3 R V W 6.6 9 20 Nov Bajo Rojo 10 192.3 R V W 4.3 9 20 Nov Bajo Rojo 10 192.3 R V W 13.5 9 20 Nov Bajo Rojo 10 192.3 R V W 5.5 10 20 Nov Bajo Rojo 12 226.3 P P H 3.4 10 20 Nov Bajo Rojo 12 226.3 P E H 18.4 10 20 Nov Bajo Rojo 12 226.3 P E H 6.7 10 20 Nov Bajo Rojo 12 226.3 P E H 2.4 10 20 Nov Bajo Rojo 12 226.3 P E H 1.8 10 20 Nov Bajo Rojo 12 226.3 P P W 1.4 10 20 Nov Bajo Rojo 12 226.3 S C W 3.5 10 20 Nov Bajo Rojo 12 226.3 S C W 3.4 10 20 Nov Bajo Rojo 12 226.3 S C W 1.3

PAGE 25

Rocky Reef Microhabitat Hawkins & Medina 25 10 20 Nov Bajo Rojo 12 226.3 P P W 1.4 11 20 Nov Bajo Rojo 18 221 P V H 6 11 20 Nov Bajo Rojo 18 221 P V H 3.2 11 20 Nov Bajo Rojo 18 221 S C H 6.6 11 20 Nov Bajo Rojo 18 221 P V H 1.3 11 20 Nov Bajo Rojo 18 221 P V H 2.2 11 20 Nov Bajo Rojo 18 221 P V W 4.1 11 20 Nov Bajo Rojo 18 221 P V W 2.6 11 20 Nov Bajo Rojo 18 221 P V W 3.1 11 20 Nov Bajo Rojo 18 221 P V W 1.6 11 20 Nov Bajo Rojo 18 221 P V W 0.8 12 22 Nov Bajo Rojo 3 291 P P H 5.2 12 22 Nov Bajo Rojo 3 291 P E H 40.6 12 22 Nov Bajo Rojo 3 291 P P H 11.1 12 22 Nov Bajo Rojo 3 291 P V H 5.2 12 22 Nov Bajo Rojo 3 291 P P H 7.7 12 22 Nov Bajo Rojo 3 291 P P W 5.5 12 22 Nov Bajo Rojo 3 291 P C W 7 12 22 Nov Bajo Rojo 3 291 P P W 8.8 12 22 Nov Bajo Rojo 3 291 P P W 2.9 12 22 Nov Bajo Rojo 3 291 P P W 5.7 13 22 Nov Bajo Rojo 7 329.5 P E H 14.7 13 22 Nov Bajo Rojo 7 329.5 P E H 2.1

PAGE 26

Rocky Reef Microhabitat Hawkins & Medina 26 13 22 Nov Bajo Rojo 7 329.5 P E H 6.4 13 22 Nov Bajo Rojo 7 329.5 P E H 5.4 13 22 Nov Bajo Rojo 7 329.5 P E H 7.4 13 22 Nov Bajo Rojo 7 329.5 P C W 10.3 13 22 Nov Bajo Rojo 7 329.5 P P W 1.4 13 22 Nov Bajo Rojo 7 329.5 P P W 5.3 13 22 Nov Bajo Rojo 7 329.5 P P W 4.7 13 22 Nov Bajo Rojo 7 329.5 P C W 2.3 14 23 Nov Islita 3 347.4 P E H 11.2 14 23 Nov Islita 3 347.4 P E H 8.4 14 23 Nov Islita 3 347.4 P E H 6.9 14 23 Nov Islita 3 347.4 P E H 6.4 14 23 Nov Islita 3 347.4 P E H 34.6 14 23 Nov Islita 3 347.4 S C W 4.2 14 23 Nov Islita 3 347.4 S C W 7.9 14 23 Nov Islita 3 347.4 S C W 6.7 14 23 Nov Islita 3 347.4 S C W 10 14 23 Nov Islita 3 347.4 S C W 6.2 15 23 Nov Islita 11 318.3 P E H 21 15 23 Nov Islita 11 318.3 P E H 15.4 15 23 Nov Islita 11 318.3 P S H 29.3 15 23 Nov Islita 11 318.3 P E H 14.7 15 23 Nov Islita 11 318.3 P E H 19.4 15 23 Nov Islita 11 318.3 S C W 16.8 15 23 Nov Islita 11 318.3 P F W 24.9 15 23 Nov Islita 11 318.3 S C W 6.2 15 23 Nov Islita 11 318.3 S C W 7.6 15 23 Nov Islita 11 318.3 S C W 19.6 16 23 Nov Islita 12 321.4 P E H 7.4 16 23 Nov Islita 12 321.4 P E H 5.3 16 23 Nov Islita 12 321.4 P E H 3 16 23 Nov Islita 12 321.4 P E H 10.3 16 23 Nov Islita 12 321.4 P E H 7.4

PAGE 27

Rocky Reef Microhabitat Hawkins & Medina 27 16 23 Nov Islita 12 321.4 S C W 3.4 16 23 Nov Islita 12 321.4 S C W 6.1 16 23 Nov Islita 12 321.4 S C W 6.6 16 23 Nov Islita 12 321.4 S C W 5.4 16 23 Nov Islita 12 321.4 P P W 2.1 17 23 Nov Islita 16 309 P E H 20.6 17 23 Nov Islita 16 309 P E H 7.9 17 23 Nov Islita 16 309 P E H 11.5 17 23 Nov Islita 16 309 P E H 50.1 17 23 Nov Islita 16 309 P E H 4.4 17 23 Nov Islita 16 309 S C W 3.8 17 23 Nov Islita 16 309 S C W 1.9 17 23 Nov Islita 16 309 S C W 2.3 17 23 Nov Islita 16 309 S C W 10.1 17 23 Nov Islita 16 309 S C W 15.3 18 24 Nov Bajo Rojo 2 228.5 R E H 4.9 18 24 Nov Bajo Rojo 2 228.5 R P H 4.4 18 24 Nov Bajo Rojo 2 228.5 R E H 6.5 18 24 Nov Bajo Rojo 2 228.5 R V H 8.2 18 24 Nov Bajo Rojo 2 228.5 R E H 6.1 18 24 Nov Bajo Rojo 2 228.5 R P W 6.7 18 24 Nov Bajo Rojo 2 228.5 S C W 5.3 18 24 Nov Bajo Rojo 2 228.5 S C W 2 18 24 Nov Bajo Rojo 2 228.5 R P W 2.6 18 24 Nov Bajo Rojo 2 228.5 R V W 3.4 19 24 Nov Bajo Rojo 8 218.5 P E H 16 19 24 Nov Bajo Rojo 8 218.5 P V H 6.3 19 24 Nov Bajo Rojo 8 218.5 P V H 2.3 19 24 Nov Bajo Rojo 8 218.5 P V H 4.8

PAGE 28

Rocky Reef Microhabitat Hawkins & Medina 28 19 24 Nov Bajo Rojo 8 218.5 P V H 6.8 19 24 Nov Bajo Rojo 8 218.5 P V W 8.7 19 24 Nov Bajo Rojo 8 218.5 P V W 9.9 19 24 Nov Bajo Rojo 8 218.5 P V W 2.1 19 24 Nov Bajo Rojo 8 218.5 S C W 7.1 19 24 Nov Bajo Rojo 8 218.5 P V W 3.5 20 24 Nov Bajo Rojo 11 187.7 P E H 10.4 20 24 Nov Bajo Rojo 11 187.7 P E H 33.5 20 24 Nov Bajo Rojo 11 187.7 P E H 41.3 20 24 Nov Bajo Rojo 11 187.7 P E H 22.2 20 24 Nov Bajo Rojo 11 187.7 P P H 1.8 20 24 Nov Bajo Rojo 11 187.7 P P W 2.7 20 24 Nov Bajo Rojo 11 187.7 P P W 3.4 20 24 Nov Bajo Rojo 11 187.7 S C W 2.8 20 24 Nov Bajo Rojo 11 187.7 P P W 1.4 20 24 Nov Bajo Rojo 11 187.7 S C W 2.1 Observation Bias We were interested in the potential bias in the number of morphospecies we observed based on the relative order quadrats were surv eyed within a sampling session. Based on our personal experience collecting data in the field, we noticed that we started each session warm and well rested, and became cold and tired as sampling continued. Therefore, we hypothesized that we observed more morphospecies in quadrats observed earlier in each s ampling session We compared when a quadrat was measured and the number of morphospecies recorded (Figure 6 ). We found no significant relationship between the number of morphospecies we recorded and the relative order we surveyed the quadrat ( one way ANOVA, p = 0. 373 ), which does not support our ide a that our search effort changed throughout a sampling session. This makes us confident that our observations were not skewed or biased due to the order in which we observed the quadrats.

PAGE 29

Rocky Reef Microhabitat Hawkins & Medina 29 Figure 6 Morphospecies richness plotted against order in which q uadrat was recorded within a given sampling session There were seven sampling sessions. Quadrats were only included if at least two quadrats were surveyed in the sampling session (N=19). Sample size varies: First (N=6), Middle (N=7), Last (N=7). We also wondered if the depth at which we surveyed quadrats had any effect on our observations, based on the idea that deeper areas are harder to observe for long periods due to being limited by how long we could hold our breath s Therefore, w e predicted that we w ould notice fewer morphospecies in deeper quadrats. However, after comparing measured depth and morphospecies richness (Figure 7), we found no significant relationship between the two variables (correlation coefficient = 0.3 68 p = 0. 109 ). This does no t s upport our hypothesis, which makes us confident that our sampling m ethods were sound and unbiased with regards to depth.

PAGE 30

Rocky Reef Microhabitat Hawkins & Medina 30 Figure 7 Morphospecies richness plotted against d epth Each point represents one quadrat (N=20).


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