Download Determination of Primary Placeholder Habitat Associations in a Kelp

Determination of Primary Placeholder Habitat
Associations in a Kelp Forest Ecosystem through UPC
Analysis [[3/4 clear indication of the study system, but doesn’t hint at the larger
ecological questions]]
Ian Moffitt
[[9/14 - Overall Clarity – line-by-line edits provided for the intro only, try to apply
these concepts to the rest of the paper and consider in your future work.
 Don’t use jargon, where a simpler word would achieve the same thing, and
definitely don’t use any words if you don’t understand what they mean!
 Make sure each sentence has a clear subject and a verb (i.e. a
PERSON/THING that is DOING something) to avoid passive voice and make
your writing easy to understand.
 Carefully review rules of punctuation and learn how to use commas, colons,
and semi-colons correctly.
 Carefully choose your connecting words (e.g. whereas, while, however, in
contrast, thus) so that they are appropriate to the sentence, because each of
these words means something slightly different.
 Read your sentences out loud to yourself (you’ll only look a little crazy) to
make sure that they flow naturally and are not broken into too many
unnecessary clauses; if they don’t flow naturally try reordering the clauses/
ideas.
 Try varying sentence length for a mixture of longer sentences that connect
multiple concepts and short sentences that make a single clear point.
 Don’t forget to connect the dots between ideas, just because you understand
how two ideas presented in adjacent sentences are related, does not mean
it’s clear to your reader.
 Call on your classmates to proof read for you! They can help identify where
your writing is unclear so that you can fix it BEFORE you turn your paper in!
Abstract: [[no abstract was required for this assignment. A true abstract should
summarize the whole paper including key questions, context, methods, results, and
conclusions]]
UPC transects were performed at Hopkins Marine Station to quantify the
occurrences of different substrate types, relief types, and species associations with both
of these habitat characteristics. This was done in an attempt to understand how niche
partitioning can attribute to the maintenance of the biodiversity found in the kelp
forest ecosystem.
Introduction: [[10/20 This introduction could be improved by: 1) beginning with
the big ecological question, how diversity is maintained in the face of interspecific
competition, and using the scientific literature to create the context for this
question, 2) identifying how this study addresses questions about niche
diversification and partitioning, 3) introducing the clear and specific questions this
study was designed to address and their associated hypotheses (in paragraph
format), and 4) addressing why your study is novel and adds to the field of
ecology.]]
Kelp forest ecosystem structure is [[dynamics are about changes through
time]] thought to be affected by species [[primary placeholder is an awkward
phrase that doesn’t make a lot of sense out of context]] associations with different
geological factors, such as substrate and relief type. These associations vary in
strength and may form the basis for inter-specific interactions that form the
complex trophic web of the kelp forest. Associations between benthic habitat
characteristics and sessile organisms are important to understand because they
help to explain the incredible amount of diversity found in the kelp forest ecosystem
as established through niche partitioning. [[you should be using citations in this
section. A better introductory paragraph would start by explaining broader
ecological context (with citations) and why we care to understand the factors that
maintain diversity in the face of competition. Then you can describe how specieshabitat associations help us examine niche diversification]]
UPC [[need to spell out uniform point contact]] transects were performed at
Hopkins Marine Station to analyze species-habitat associations with respect to
substrate and relief in the kelp forest ecosystem. Depending on the relative
proportion of each type, species associations were statistically determined to
strongly correlate, moderately correlate, or weakly correlate to these geologic
features. Strongly positive correlations between geologic features and primary
placeholder type can be used to evaluate niche diversification in that certain species
are found to occur there more often than would be expected by chance, indicating
that they have adapted to survive better than other organisms in that area. If two
organisms are found to exhibit strong associations with the same type of habitat,
there is a possibility that the organisms are competing for space. Strongly negative
correlations are important in that they suggest a particular primary placeholder is
either incapable of surviving in a habitat or was outcompeted by another species in
the past (Watanabe 1983). [[This is a great explanation of how results can be
interpreted, but it doesn’t really belong in the introduction.]] We hope to identify
different patterns of species-substrate associations that suggest niche partitioning
to help explain how the diversity of species in the kelp forest is maintained. Hopkins
is an ideal location to test this hypothesis because it is located in a no-take marine
reserve that frees it from most anthropogenic influences that could bias the data.
There is also a large amount of primary placeholder diversity as well as ample
variation in substrate and relief type.
Methods:
[[8/18 - The methods section should begin by briefly describing the general
approach (observational, UPC method to characterize primary substrate holders,
substrate type, and relief). Then talk about the system and expand on why it’s a
good site for this study (something that should be introduced in the intro). Then you
need to identify the specific hypotheses and explain how your data collection
methods will allow you to test each hypothesis. After you’ve explained WHY you did
things the way you did, you want to provide a detailed description of methods,
including data analysis..]]
Site:
We conducted a UPC survey at Hopkins Marine Station (36º36’N,
121º54’W) of Stanford University. The geology of the site is ideal for
determining species associations with different habitats. Large granitic
outcrops in shallow water give rise to moderate and high relief bedrock
surrounded by sand flats in deeper water (Watanabe 1983). The survey was
conducted on April 10, 2012 in the morning when the weather was overcast,
in-water visibility was about 5 meters, and the conditions were placid. The
tide was very low (-0.87 ft) which contributed to a depth range of seven to
ten meters. [[could explain a little more clearly WHY the characteristics of
this site are good for this kind of study]]
Approach:
[[start with the more general approach and why it is suited to
answering your questions, then link specific methods to each of your
hypotheses and explain how they’ll allow you to test thos hypotheses before
you launch into all the details]] The UPC transects were conducted by ten
buddy pairs using SCUBA along the permanent transect cable from 90-135
meters. Each buddy team collected 120 data points for a total of 1,200 [[good
to have total number of data points!]]. The uniform points were picked to
occur at every half meter along a 30 meter transect performed on and off
shore (270, 90 degrees respectively). Transects were split in half by each
group composed of a buddy team, so one person was always 2.5 meters in
front of the other. The substrate and primary placeholder was determined
indiscriminately as the object located directly underneath the previously
determined uniform point along the transect. Relief was recorded by
determining the maximum height change in a .5/.5 meter window of the
uniform data point.
Four types of substrate were differentiated as sand, cobble (<10 cm),
boulder (10cm-1m), and bedrock (>1m). Four classifications of relief were
differentiated as flat (0-10 cm), slight (10cm-1m), moderate (1-2m), and high
(>2m). The primary placeholders that were counted are referred to in Figure
1.
Figure 1 [[ I like the table to list
species]]
Inanimate
Red Algae
Coralline
Brown Algae
Tube Worms
Bare rock
Branched
Crustose
Cystoseira
Solitary
osmundacia
tubeworm
Dictyoneurum
Diopatra ornata
Bare sand
Leafy
Articulated
californicum
Shell debris
Bushy
------------------
Egregia
Phragmatopoma
menziesii
californica
Sediment
Lacy
------------------
Desmarestia
Dodecaceria spp
Dead
Encrusting
------------------
Macrocystis
--------------------
holdfast
red
----------------
Turf
holdfast
------------------
Laminariales
--------------------
holdfast
-----------------
------------------
------------------
Dictyotales
--------------------
spp.
Snails
Cnidarians
Tunicates
Other
Serpulorbis
Corynactis
Colonial tunicate
Scallop
squamigerus
californica
Petalochonchus
Cup coral
Solitary tunicate
Embedded
monteryensis
cucumber
-----------------------
Other anemone
------------------------- Barnacle
-----------------------
Hydroids
------------------------- Bryozoan
-----------------------
Stylaster
------------------------- Sponge
californica
-----------------------
-------------------------- ------------------------- Mussel
Species-Habitat associations
The substrate and relief data were combined with the species data to
determine a standardized measure for the deviation from substrate-species and
relief-species associations expected by chance. The values obtained take into
consideration the total occurrence of a particular type of substrate and use that as
the “expected” level of species association. Deviations from this “expected” value
that are >2 or <-2 are considered to be strong associations, deviations <2 and >1 or
>-2 and <-1 are considered moderate, and all other deviations are considered weak.
Only strong associations were considered in this study to determine if specieshabitat interactions were occurring in the ecosystem.
Results:
[[7/16 - would be improved by inclusion of: 1) general results (from first two graph
pages that Pete presented, 2) description of the results relative to each hypothesis
including whether associations were positive or negative and whether or not the
results supported your hypotheses, and 3) inclusion of more figures and better
figure formatting (try using a 1x2 table for your figures with the actual figure/table
in one cell and the caption in the other an combine all the figures into a single
section, either within the results section or at the end of the paper to avoid
formatting problems and interrupted flow)]]
Substrate and Relief
We found that the substrate was composed of 40% sand, 6% cobble,
20% boulder, and 34% bedrock. 42% of the relief type was slight, 40% was
flat, 14% was moderate and 6% was high. Most of the flat relief was
associated with the sandy substrate while the slight, moderate, and high
reliefs were associated with the bedrock and boulder substrates. [[good
general results]]
Species Associations with Relief [[good to organize by hypothesis, but you
need more details here!!]]
Eleven primary substrate holders exhibited strong interactions with the four
levels of relief (See Figure 2). [[you should describe some of these in the text]]
Species Associations with Substrate
Eighteen primary substrate holders exhibited strong interactions with the
four substrate types (See Figure 3) [[you should describe some of these in the text]]
Figure 2
Figure 3
Figure 2 represents the deviation from
expected values of 4 types of relief with
respect to species associations. From left
to right the order of relief is: flat, slight,
moderate, and high
Figure 3 represents the deviation
from expected values of four
types of substrate with respect to
species associations. From left to
right the order of substrate is:
sand, cobble, boulder, and
bedrock.
Discussion:
[[13/22 – You did a good job of tying the discussion back to the big ecological
questions introduced in the introduction, and a fairly good job of summarizing the
results and interpreting them, including possible mechanisms for the species-
habitat associations you observed (both why they exist and how they’re
maintained). However, to improve the discussion, you should: 1) more clearly
address whether or not your results support your hypotheses, including problems
with your study design that may have influenced your results, and 2) use the
scientific literature to provide context for your results (i.e. compare to previous
similar studies including AT LEAST 2-4 citations in the discussion, not all of them
from readings and lectures!)]].
The strong associations of certain primary placeholders to specific types of
relief and substrate compel us to ask why and how they occur in higher densities on
these particular habitats. An analysis of why the strong associations between
species and habitat type occur allows us to better understand the mechanism
through which the biodiversity in the region is maintained. Furthermore,
understanding how different benthic species interact in close proximity to one
another, gives us insight into how these organisms may have evolved and how they
are still evolving through competitive interactions to better adapt to a niche.
Species Interactions with substrate
Articulated coralline algae spores recruit best to boulder substrates (Figure
3) (http://www.mbari.org/staff/conn/botany/reds/ian/artcor/ecology.htm)
Although the articulated coralline did exhibit a positive association to bedrock as
well, it did not exhibit a strongly positive association (Not shown in results). This
could have been due to error in the sampling as it is somewhat difficult to
distinguish between the different types of red algae, or it could be indicative of
strong competition for space on bedrock, causing the competitive exclusion of
articulated coralline spore recruits. Its strong associations with moderate relief (see
results) confirm its preference for boulders and bedrock (it was found that boulders
and bedrock are typically moderate to high relief) and further suggest that it cannot
recruit to sandy substrate.
Indeed, all of the red algae recorded for this survey, exhibited negative
associations with sand except for the lacy reds (see Figure 3). Interestingly, the
branching, crustose, and encrusting red algae co-occurred on bedrock while the
articulated, branching, bushy, and leafy coralline algae co-occurred on boulders.
Since all of these associations are strong, it is quite possible the algae that spatially
co-occurs is competing for space, or recruiting to a unique microscopic cue on the
substrate. The red algae that associates independently (crustose and encrusting red
are distinct from articulated, bushy, and leafy) has most likely already undergone
competitive interactions in the past leading to niche diversification. Furthermore, it
should be noted that the branching reds may exhibit competitive superiority or have
less specific recruitment cues, in that they strongly associate to both boulder and
bedrock substrate.
The strongly positive association of cup coral to bedrock and high relief
reflects its preference for rocky areas exposed to more water flow that provide
better feeding conditions, but may also be indicative of the larval dispersal of the
organism. Cup corals (specifically Balanophyllia elegans) do not have larvae that
disperse long distances (Altieri 2003). The larvae crawl along the substrate and
usually do not disperse more than 1.3 meters away from the parent individual
(Altieri 2003). From an ecological standpoint, this suggests that if one individual is
able to colonize a rock, soon many individuals will colonize any free space on that
rock, leading to very high population densities in isolated areas. Another colonial
Anthozoan known as Corynactis californica was observed to occupy a very similar
niche. This suggests that some competitive interactions may currently be taking
place between the two species (Chadwick 1991).
Another potential for competitive interactions can be seen in the strong
positive associations of both barnacles and colonial tunicates to bedrock and high
relief (see results). It has been noticed that colonial tunicates (particularly
Didemnum spp.) often grow over barnacles at Hopkins (Kim, Zarri personal
communication). These organisms may be undergoing competitive interactions that
could lead to niche partitioning over evolutionary time.
The findings of this study show that there are patterns of association
between substrate/relief type and different primary placeholder species. Strong,
positive habitat associations among different species suggest competitive
interactions are taking place to establish niche partitioning. Strong, negative
associations show that an organism is incapable of colonizing an area because of its
own recruitment limitations or because it was outcompeted evolutionarily. It is
important to understand the habitat associations of primary placeholders if one is to
understand how and why the amount of biodiversity present in the kelp forest
ecosystem can be maintained.
Citations: [4/6 – at LEAST 6 references were required for this assignment and
please review guidance on formatting references!]]
Altieri, A.H.2003. Settlement cues in the locally dispersing temperate cup coral
Balanophyllia elegans. Biological Journal 204: 241-245
Chadwick,N.E.1991. Spatial distribution and the effects of competition on some
temperate Scleractinia and Corallimorpharia. Marine Ecology Progress Series 70:
39-48
Ehrenreich, I.2001
http://www.mbari.org/staff/conn/botany/reds/ian/artcor/ecology.htm
Watanabe,J.M.1984. The influence of recruitment, competition, and benthic
predation on spatial distributions of three species of kelp forest
gastropods(Trochidae: Tegula)