The Importance of Qualitative Sampling Methods: Examining Species Abundance
and Diversity in a Kelp Forest
Brett Banka
Title: 2 pts
Abstract [[2, 0, 0, 0, 0, 2]] 4 pts
[[your abstract is very “system” focused rather than question focused… if you bring your
objective (question) up to front and precede it with sentence as to why this is your
objective, you have a more focused and informatinve Abstract.] The objective of this
survey was to determine the effectiveness and accuracy of qualitative sampling by
measuring species abundance and diversity in a subtidal environment. Kelp forest
ecosystems are highly dynamic in which they experience continuous temporal and spatial
changes at various magnitudes. An important topic in kelp forest ecology involves
examining the responses and recovery of these systems in the event of environmental
disturbances. The magnitude and impact of these environmental disturbances vary from
small-scale disturbances to large-scale El Nino Southern Oscillation (ENSO) events that
can affect the proper function and persistence of kelp forest ecosystems (Edwards 2003).
[[don’t use citations in an Abstract]] The patterns and variability in the distribution and
abundance of species in these systems are indicators of ecosystem function and overall
health (Edwards 2003). Qualitative sampling methods were used in this study to obtain
species abundance and diversity in a sub-tidal habitat of Hopkins Reef in Monterey Bay,
CA. [[don’t hyphenate subtidal.]] This study indicates that qualitative surveys are subject
to high variability but are often necessary when conducting research with parameters
such as time constraints and limited sampling methods when conducted in subtidal
environments.
Introduction [2, 2, 2, 2, 4, 2, 4, 0, 4, 4, 2] 28 pts
[In the future, I would switch the order of your first two paragraphs! Because this is all
about qualitative sampling, emphasize that by raising the question about this sampling
method first, THEN say why we want to explore its use in kelp forest ecosystems and
why it is important for our understanding of those systems.]
Kelp forest ecosystems are highly dynamic in which they experience continuous
temporal and spatial changes at various magnitudes. An important topic in kelp forest
ecology involves examining the responses and recovery of these systems in the event of
environmental disturbances. The magnitude and impact of these environmental
disturbances vary from small-scale disturbances to large-scale El Nino Southern
Oscillation (ENSO) events that can affect the proper function and persistence of kelp
forest ecosystems (Edwards 2003). Species diversity, coupled with species redundancy is
important in enabling marine subtidal communities to resist and recover from such
disturbance (Palumbi et al 2008). Kelp forests are among the most productive ecosystems
in the world and provide valuable habitat and resources that promote high species
abundance and diversity (Edwards 2003). Kelp forests are composed of spatially
heterogeneous mosaics of habitat-forming species that can support entire ecosystems
(Gorman and Connell 2009). The patterns and variability in the distribution and
abundance of species in these systems are indicators of ecosystem function and overall
health (Edwards 2003). [[true but a stretch, give me more reasons to study distrinbution
and abundance!]
Species abundance and diversity can be measured using quantitative or qualitative
methods. Quantitative sampling involves methods of analysis that uses numeric
representations, whereas, qualitative sampling analyzes non-numeric representations
(Yoshikawa et al 2008). These methods are often used to determine taxonomic
composition and species richness and diversity (Garcia-Criado and Trigal 2005).
Qualitative samples are often smaller than quantitative because they are often more
difficult to obtain due to time and collection constraints (Yoshikawa et al 2008). [[???
You mean the other way around, right???] Qualitative sampling methods were used in
this study to obtain species abundance and diversity in a sub-tidal habitat of Hopkins
Reef in Monterey Bay, CA. The objective of this survey was to determine the
effectiveness and accuracy [precision… we can’t assess accuracy] of qualitative
sampling by measuring species abundance and diversity in a sub-tidal environment.
The precision in qualitative sampling methods are prone to differences due to
conflicting analysis based on a subjective (1-5) scale ranging from absent, rare, present,
common, and abundant. This level of measurement can seem arbitrary and may be
interpreted in various ways. Therefore, we expected to observe a difference in qualitative
sampling results of species abundance and diversity between and among buddy pairs.
[don’t suggest you have expectations… suggests you are biased. You can say that this
arbitrariness could lead to great variation among observers so we wanted to test to see
whether and how much this was a problem.]] Variance component analysis determined
[[don’t give results here… say that you used this method to test your hypotheses.]] the
accuracy of this qualitative survey with respect to species abundance and diversity in
relation to: depth (shallow versus deep transect), buddy (difference between buddy pairs),
and meter (distance along transect cable). [State these as hypotheses!! We designed our
study to determine whether qualitative sampling could be used to test the following
hypotheses: that differences between buddies were less that among transects, that species
abundance differed between depth zones, that species abundance differed across the kelp
forest. Then use use these hypotheses to structure the Methods and Results sections.]]
There are some characteristics of certain species and taxonomy that may be
beneficial in using qualitative sampling methods. The behavior, morphology, and spatial
distribution of organisms can influence the effectiveness and accuracy of qualitative
sampling. Good candidates for qualitative sampling include organisms that are sessile,
less mobile, non-cryptic, and easily visible. Poor candidates are those that are highly
mobile, reclusive, cryptic, and not readily visible. [wait just a damn minute here… you
are giving us results, instead of stating that you are going to test hypotheses that certain
traits of species lend them more or less appropriate for qualitative sampling by comparing
the precision of estimates of species with different traits.]] Of the three taxonomic groups
surveyed in this study, we hypothesize that qualitative sampling methods would favor
algae over invertebrates and then fish. [ but why? Tie this back to those traits you just
rattled off. Nice direction and hypothesis!]] [[OUTSTANDING use of citations!]]
Methods [2, 1, 0, 0, 0, 2, 2, 0, 1, 0, 2, 0, 4, 2, 4, 2, 2] 24 pts
First tell me something about the general approach… To determine the effectiveness of
qualitative surveys for characterizing the distribution and relative abundance of species in
kelp forest ecosystems and the species this approach is most applicable for, we conducted
field surveys to qualitatively measure the distribution and abundance of 20 species of
fish, inverts and algae in a central California kelp forest.
Study Area
This qualitative sampling survey was conducted in the sub-tidal kelp forest of Hopkins
Reef at Hopkins Marine Station in Monterey, CA (36°37'16.15"N Latitude,
121°54'6.28"W Longitude). This survey was conducted to determine the species diversity
[? or abundance?] and distribution along the transect cable on the deep-offshore and
shallow-near shore area using qualitative sampling methods. Data WERE!!! collected
between 0900 and 1100 on September 27, 2011. [excellent, but tell me something about
this kelp forest and cite literature that describes it (like Watanabe).]
Image 1) Map of Hopkins Reef transect cable
Qualitative Survey
Observational qualitative surveys were conducted by 14 dive teams on SCUBA to
estimate the species diversity of 6 species of algae, 9 species of fish, and 13 species of
invertebrates at Hopkins Reef (Table 1).
Table 1) Target Species List [[Make this title more informative and put it above the
Table… What is this table about? The five species of algae, plant, nine fishes, and 13
species of invertebrates that we ranked abundance of along our transects. ]]
Algae and Plants
1) Cystoseira osmundacea
2) Gigartina corymbifera
3) Dictyoneurum californicum
4) Macrocystis pyrifera
5) Dictyonueropsis reticulata
6) Phyllospadix spp. (sea grass)
Fishes
1) Oxylebius pictus (painted greenling)
2) Hexagrammos decagrammus (kelp greenling)
3) Sebastes mystinus (blue rockfish)
4) Sebastes carnatus (gopher rockfish)
5) Sebastes chrysomelas (blk/ylw rockfish)
6) Sebastes atrovirens (kelp rockfish)
7) Embiotoca jacksoni (black surfperch)
8) Embiotoca lateralis (striped surfperch)
9) Damalichthys vacca (pile perch)
Invertebrates
1) Asterina miniata (bat star)
2) Pycnopodia helianthoides (sun star)
3) Pisaster brevispinus (short spined star)
4) Pisaster giganteus (great spined star)
5) Urticina picivora (fish eating anemone)
6) Urticina lofotensis (white-spotted anem.)
7) Pachycerianthus fimbriatus (sand anem.)
8) Balanophyllia elegans (cup coral)
9) Tethya aurantia (ball sponge)
10) Calliostoma ligatum (ring topped snail)
11) Loxorhynchus grandis (sheep crab)
12) Haliotis rufescens (red abalone)
13) Strongylocentrotus fransiscanus
[[So you boned the following… you gave us various questions you were going to address
in the Intro, but now you are not telling us what those questions are and how you
designed the sampling and analyses to answer them. More importantly, you don’t
translate the questionsin to hypotheses and tell us how you will test the hypotheses.]]
Be careful… this is all in third person… try to switch itto first person…
Each dive team collected data at a designated survey marker at 5m intervals along a 70m
transect. At each marker, dive teams used meter tapes to deploy two 30m transects, one
on the deep-off shore (heading 90o) and one on the shallow-near shore (heading 270o).
[We recorded… Data WERE collected at each out and in leg of the 30m transect for both
deep-off shore and shallow-near shore surveys. Data WERE collected by each diver in a
(1m wide x 2m length x 1m high) volume of water on each side of the transect tape. We
assessed… The relative abundance of each target species was assessed on a 1-5 scale
(1=absent, 2=rare, 3=present, 4=common, and 5=abundant). Each member of each buddy
team collected data independently. We used… Variance components analysis to compare
results among the 14 dive teams to determine the pattern of variability introduced at each
level including: depth, buddy pair, and distance along the transect cable.
Results
Figure 1) Percentage of variance associated with: depth (deep versus shallow transect),
buddy (between buddy pair), and meter (distance along transect cable). Percentage of
variance was 23% for depth, 37% for buddy, and 40% for meter.
Figure 2) Percentage of variance components by taxonomy (algae, fish, and
invertebrates) associated with: depth (deep versus shallow transect), buddy (between
buddy pair), and meter (distance along transect cable). Percentage of variance of
taxonomy: algae (40% buddy, 10% depth, and 50% meter); fish (18% buddy, 22% depth,
and 60% meter); invertebrates (50% buddy and 50% depth).
Figure 3) Mean abundance for all species (fishes, algae, and invertebrates). Mean
abundance of taxonomy: fishes ~1.8; algae ~2.8; and invertebrates ~2.5.
Figure 4) Relative difference between buddies (%) based on rank data (1-5).
Figure 5) Percent disagreement between buddies based on presence and absence data.
Figure 6) Relative difference (%) between buddy pairs as a function of mean abundance
of species.
Discussion
This qualitative survey was conducted to measure the effectiveness and accuracy
of qualitative sampling methods in determining species abundance and diversity. Our
results coincide with our hypothesis that our results differed among buddy pairs. Our
results in figure 1 demonstrate that percentage variance is associated with differences in
depth, buddy pair, and distance along the transect cable. The factors of depth and meter
were expected to account for larger proportions of variance based on differences between
locations. The percentage of variance associated with the buddy factor accounted for
approximately 37% of variance. Factors responsible for this variance may be due to
different interpretations of the (1-5) abundance scale between buddy pairs. Other factors
may be due to inconsistency in sampling methods conducted by different buddy pairs.
Overall, the buddy factor had a substantial effect on our sampling methods.
The percentage of variance components by taxonomy associated with depth,
buddy, and meter displayed that percentage of variance was responsible for 50% variance
for algae with respect to distance along the cable, as well as 60% for variance in fish;
whereas, variance in invertebrates had no effect with respect to distance along the cable.
Reasons for no variance in invertebrate abundance and diversity is due to the 50%
variance in the buddy factor and 50% variance with respect to depth. Again, the buddy
factor is responsible for a substantial amount of variance.
The mean abundance for all species was separated into taxonomy (figure 3).
Mean abundance increased in taxonomic order of fish (~1.8) to invertebrates (~2.5) to
algae (~2.8) as we expected in our hypothesis. This result could be heavily influenced by
ability to sample organisms based on their level of assessment difficulty. Therefore, fish
being highly mobile makes it more difficult to sample, in contrast to algae that are sessile
and non-mobile.
The relative difference between buddies was assessed based on percentage of
difference and rank data scale (1-5) (figure 4). All results indicated a consistent
difference between buddies for all taxonomic groups. This result supports our hypothesis
that there is a difference between buddy pairs when assessing species on a qualitative
scale from absent, rare, present, common, and abundant. Differences in this assessment
may be due to difference in the interpretation of abundances of organisms based on the
(1-5) scale. The (1-5) scale was not discussed between or among buddy pairs prior to the
survey, therefore, leaving a broad gap for various personal interpretations.
Percent disagreement between buddies was also assessed based on presence and
absence data, which was analyzed and sorted into species and taxonomic groups (figure
5). Only two of the 28 species assessed had no disagreement based on presence and
absence. These species were giant kelp Macrocystis pyrifera and the bat star Asterina
miniata. Percent disagreement for these species could be low due to their assessment
characteristics that make them easier to identify and survey than other species.
The percentage of relative difference between buddy pairs was assessed with
respect to mean abundance of species (figure 6). The difference in disagreement peaked
at nearly ~80% at mean abundance level 2 (rare). Different assessment of whether a
species is rare or not can be highly variable based on personal interpretation.
This study exemplifies that qualitative surveys are subject to high variability but
are often necessary when conducting research with parameters such as time constraints
and limited sampling methods when conducted in sub-tidal environments. Qualitative
sampling is often used to measure the abundance of species to determine the qualitative
composition of a community. The assessment of the composition of species abundance
and diversity is often useful in indicating the structure of an ecosystem. Ecosystem
structure can indicate the stability of a system and it’s ability to respond to disturbance.
Not only are kelp forests are vulnerable to environmental disturbance; they are also
sensitive to destructive anthropogenic influences. Human-induced disturbances can lead
to altered productivity and structure of kelp forest habitats resulting in regime-shifts that
can wipe out entire kelp forest communities (Gorman and Connell 2009). Kelp forest
systems and the species abundance and diversity they support are important indicators of
the health of temperate sub-tidal marine environments.
References [3, 3] = 6 pts [don’t capitalize journal articles…
Edwards, M. 2004. Estimating scale-dependency in disturbance impacts: El Niños and
Giant Kelp Forests in the Northeast Pacific. International Association for Ecology
138:436-447
Garcia-Criado, F. and Trigal, C. 2005. Comparison of several techniques for sampling
macroinvertebrates in different habitats of a North Iberian pond. Hydrobiologia
545:103-115
Gorman, D., and Connell, S. (2009) Recovering subtidal forests in human-dominated
landscapes. Journal of Applied Ecology 46:1258-1265
Palumbi, S. et al (2008). Ecosystems in action: lessons from marine ecology about
recovery, resistance, and reversibility. Bioscience 58:33-42
Yoshikawa, H. et al (2008). Mixing qualitative and quantitative research in
developmental science: uses and methodological choices. Developmental
Psycology 44:344-354