Total score: 79/100

Title [[4/4 – includes all the important bits of information]]

Associations Between Substrate Type and the Mobile Invertebrate Community Structure in the Hopkins Marine Station Kelp Forest, Monterey, California

Emily Tucker

May 17, 2012

ABSTRACT [[not required for this assignment, but this one is a bit long and detailed

Niche partitioning and habitat structure are important factors that have dominated species relations and determine the biotic communities of organisms. In this study, we look at the associations between the swath species [[not everyone knows what you mean by “swath species”]] composition and habitat as well as uniform point contact (UPC) species composition and habitat [[again you should not assume that people know what this means]]. In addition to the niche implications, this combined analysis of UPC and Swath will give us insight into the fundamental vs. realized niches of various kelp forest species. Data was collected at Hopkins Marine Life Refuge in Monterey, California, 36°36’N, 121°54’W on April 10, 2012. In the first collection, we preformed an observational study using the uniform point contact method of sampling in order to characterize the primary substrate holders, the relief, and the type of substrate. In our second data collection we used a swath transect on the 17th of April 2012 that was two meters wide and thirty meters long, subdivided into five-meter sections. By comparing these two sets of data we are trying to determine if there is a correlation between species/species or species/substrate. Analysis of variance (ANOVA) was used to determine if there were associations between species and habitat, and species and species. We will use a variance component table to determine if habitat or species is more important for predicting where macro invertebrates will reside. The results obtained from the ANOVA indicate strong relationships between swath and UPC species, as well as species and the habitat attributes on which they are found. There were also strong associationsbetween the swath species and the UPC species. We used a relatively small, spatial scale to measure the substrate relief and species found there. Despite the challenges associated with sampling underwater we still see patterns of association indicating that there are strong relationships between organisms and their niches in the kelp forest.

Clarity [[12/14 – watch out for passive voice! Also work on shortening your writing so that your main points pop out more clearly. What you write is good, but sometimes the important bits can get lost]]

INTRODUCTION [[16/20 – You do a good job of introducing the big ecological questions, but you should go into a bit more depth there before you seque into your own questions/hypotheses and the specifics of the study. Overall, a bit on the long side, but you clearly understand the concepts!]]

Niche partitioning and habitat structure are important factors that dominate species relations and determine the biotic communities of organisms. If there’s no niche for an organism to occupy, or overlap between species’ roles is too great, one will either have to adapt to inhabit a new niche, leave the area, or die out [[good, you introduce the big questions and the “so what” nicely here, but you should probably expand on this a bit and ground it in the scientific literature]]. Ecosystems in general provide us with a better understanding of the interaction among organisms. Terrestrial ecosystems have been well sampled but aquatic ecosystems, specifically kelp forests, have been vastly understudied. This is increasingly not the case, as they are more easily accessible with the utilization of scuba and their proximity to shore however there are challenges that are not present in the sampling of terrestrial ecosystems.

In this report we will use the data collected from the UPC as well as data collected using a swath [[you can’t assume people know what this means!]]. Combining these two data sets gives a depiction of the association strengths between substrate type and relief in relation to the mobile invertebrate community found atop these substrates. In addition to the niche implications, this combined analysis will give insight into the fundamental vs. realized niches of various kelp forest species.

The study was conducted on the same meter mark in the same location at Hopkins Marine Life Refuge, Monterey, California as the previous UPC data collection. Because the study was conducted in a kelp forest, the species diversity found there is high; this will give us a broad range of species interactions and consequentially, more associations that can be recognized . Kelp forests provide good habitat for a multitude of species ranging from micro invertebrates to large vertebrate predators. This is due to the fast growth rates and availability as a food source of Macrocystis pyrifera (Wantanabe, 1984). The kelp, in this case Macrocystis pyrifera extends from the rocky substrate up to the surface of the water thereby creating habitatomesin many different areas ofthroughout the water column. In this study we are concerned only with the benthic interactions but having high species diversity is important to a healthy ecosystem. The fact that this is a marine reserve that is in the protection of the bay makes this an applicable site to do research. The species are not battling with treacherous conditions that will bring species numbers down, nor is there excessive contamination of the water or large amounts of anthropogenic disturbances to the communities with fishing or harvesting of kelp.[[the most important thing is the diversity of habitats and species present, because this makes it possible for you to DETECT species-habitat associations. If all the habitat was uniform …]]

In this study we are combining two types of sampling methods to get a complex picture of the associations between the macro and micro invertebrates found at Hopkins and their associations with the substrate types found there. UPC is a way to categorize organisms that are primary placeholders on the substrate. Often times these organisms are too small or numerous (cup corals) or just not feasible to count due to growth patterns (things like sponges or encrusting red coralline algae that would need percent cover counts). UPC chooses randomly assigned points along a transect tape and looks at the organism directly beneath that point so percent cover or the amount of the species present is not an issue. UPC also takes broad assessments of what kind of relief is under that point and what kind of relief is around it. Swath sampling looks at the larger mobile invertebrates such as crabs, sea stars and mollusks. These are mobile creatures that live on top of the substrate and the primary placeholders. In our first hypothesis we predict that the presence of certain types of primary placeholders sampled in the UPC will be indicative of the macro-invertebrates sampled in the swath that are found there. The second part to hypothesis one states that there will be associations between the habitat attributes (substrate type and relief) and the macro-invertebrates that make their homes on top of this substrate. Our second hypothesis takes into account hypothesis one and its speculated results that there will be associations between species/species and species/habitat and goes further by stating that between the two types of associations that we are looking at one (either UPC species or substrate) will be more indicative of macro-invertebrate swath species found there. In short, there will be different association strengths between the two associations. Our third hypothesis is looking solely at the interactions between the UPC species and the swath species and their associations or disassociations with each other individually. These interactions will give a more complex picture if what kinds of micro-invertebrates are interacting with specific species on a more individual level. Interspecies associations would be indicative of fundamental and realized niches. Determining the fundamental vs. realized niches allows us to see where a species can live and where it is actually found. The differences between the two can lead to inferences as to what is driving these species to occupy a fraction of the space they are suitable for (e.g. competition for light, food, space, etc.). If it were to be the case that species/species were stronger than species/habitat one could look into the species that were being affected and look at the key ecosystem engineers. Ecosystem engineers are organisms that are influencing the availability of resources to other organisms and both positively and negatively affect the species richness of a particular ecosystem (Jones, C.G., Lawton, J.H., Shachak, M., 1997). Such manipulation of the habitat could lead to competition for space, indicative of niche partitioning. If it were found [passive voice] that species/habitat associations were stronger it would be more indicative of the boundaries of realized vs. fundamental niches. We predict that there will be stronger species/habitat associations. It is also hypothesized [passive voice] that there will be strong associations and disassociations for specific species that we have sampled in this ecosystem. These species interactions are more evidence that while species may have a broad range of depths or substrate that they can tolerate, they only inhabit a fraction due to other interaction whether it’s with the environment or with other species. [[This description of the questions and hypotheses is good, but overly long for the intro, you should try to condense it in the future]]

Our study is helping discover the relationships between these species and their interactions not through its uniqueness of technique but in its scale. We are sampling on a five-meter scale which enables us to delve into the species to species relationships at a greater level of detail. [[good job getting at the novelty of this study!]]

METHODS [[16/18 – nice job, you could use subheadings to make it a bit easier to follow and make sure you describe the data analysis completely]]

Data was collected at Hopkins Marine Life Refuge in Monterey (HMLR), California, 36°36’N, 121°54’W in April 10, 2012. In the first collection we preformed an observational study using the uniform point contact method of sampling (UPC) in order to characterize the primary substrate holders, the relief, and the type of substrate. In our second data collection we used a swath transect on the 17th of April 2012 that was two meters wide and thirty meters long that was subdivided into five-meter sections [to count what?]. Both data collections were done using SCUBA. This sampling allowed us to categorize the macro-invertebrates found and their relative abundances along the same transect as the UPC collection. We linked the two sets of data using analysis of variance to determine the relative importances of species/species interactions versus species/habitat interactions. [[you need a bit more info here]]

HMLR is a good site for this research because it is protected from harsh winds and strong wave action. In addition to being protected from rough weather, its anthropogenic use is limited to those doing research. The ecosystem has not been fished or otherwise disturbed by having organisms taken from it. It has a diverse substrate of granite boulders and bedrock with variable relief, and a high turnover of Macrocystis (Wantanabe 1984). In many cases the variability of a habitat has important implication for the structure of the ecosystem around it (Karr 2011). At Hopkins Marine Station the substrate is highly variable and in this case its large amounts of relief create increased surface area for the invertebrate communities to occupy. Because the substrate is so packed with life and there is rarely a patch of bare rock, interactions are inevitable and visible in the fundamental vs. realized niches that these species are occupying.

Hypothesis 1: Associations between swath and UPC species and associations between these species and substrate

In the UPC analysis we sampled ten points within each five-meter block. Each point was recorded as having a specific kind of substrate type, primary placeholder, and relief. This data was then superimposed onto the swath data (Figure 1). Like the UPC collection, swath collections were done on the same heading and were divided into five-meter blocks. By comparing these two sets of data we are trying to determine if there is any kind of correlation between species/species or species/substrate. Analysis of variance was used to determine if there were associations between species and habitat and species and species. We believe that there will be associations between both species/species and species substrate. [[nice!! This is exactly what I was looking for]]

Figure 1. A spatial scale representation depicting the UPC transect and the sSwath transect. Analytically the two were lined up as is demonstrated here. Species substrate and relief were counted in the UPC swath and compared to the macro-invertebrates that were found in the swath. The upper line represents the UPC data collection and it’s five meter increments with ten pointed sampled within each increment. The lower set of boxes represents the swath data collection separated into five-meter boxes.

Hypothesis 2: Differences between association strengths

We used the same method of taking the data collected with the UPC and running it with the data collected with the swath.We did this in order to see if there was any correlations between the species and substrate found at a small-scale level with the species found at a more macro level. By utilizing the different categories of placeholder species, relief, and substrate we can analyze the associations with the macro-invertebrate species separately to determine if there are varying strengths of associations. In addition, we can test whether species or habitat is more indicative of thetypes of macro-invertebrates found in each location. We used a variance component table to determine if habitat or species is more important for predicting where macro invertebrates will reside.

Hypothesis 3: Strong associations/disassociations for specific species

When we collected our data, both for the UPC and the swath we looked at specific species.This enables us so see if there are specific micro-to-macro species associations or disassociations. We believe that there will be significant associations and disassociations between the two species categories L. gibberosa/C. stelleri and M. pyrifera/C. osmundacea. We chose to look at four species in pairs and the ones we chose were Lithopoma gibberosa/Cryptochiton stelleri (two mobile mollusks) and Macrocystis pyrifera and Cystoseria osmundacea (two sessile algal species). We are interested in the mollusks because they are both grazers that occupy the same fundamental niche. Being mobile they are physically capable of occupying each kind of substrate sampled but our results will indicate where it is they actually are found, and with what other UPC species they associate. The two algal species are important to sample because they are the only algae for which we have data. They are sessile organisms that occupy roughly the same niche and require the same things for survival (light, space, nutrients etc.). They both create habitat for others but one is a canopy species while the other is an understory species.The different growth characteristics of these two algal species could effect their niche partitioning.

At Hopkins Marine Station there is a permanent cable installed along the bottom of the ocean on a 0° to 180° heading with meter tags every 5 meters. Ourteam of divers based transects off these five-meter tags. The diving was done in pairs using 30m transects. Each pair did two transects on two different dives, one on a 90° heading from the cable and one on a 270° heading off a specific meter mark from 90 to 135. In order to do the UPC data collection, the meter tape was held flush to the bottom while each buddy sampled either the first 5 spots or the second five spots at .5m increments within each five-meter segment of the tape. The substrate immediately under the meter tape at the respective increment was recorded. If the tape had fallen over a ravine where the tape could not be held flush, the substrate estimated to be under the point on the meter tape was counted. The depth range over which the study was done was 7.3m to 12.3m.

The buddy pairs were the same for the swath and each pair went to the same meter mark that they had sampled before along the permanent cable. Each pair had a thirty meter tape that was run out on a 90° heading on the first dive and a 270° heading on the second dive. The swath was one meter on each side of the tape and was subdivided on the data sheet into five-meter blocks (Figure 2). We were looking at specific species of sea stars, anemones, urchins, cucumbers, crustaceans, mollusks, tunicates and one sponge. If, in a five-meter segment, there were more than fifteen individuals of one species the meter mark at which the number fifteen was reached and the counting ceased for that species in that section five-meter section.