Analysis of platform densities and other Marbled Murrelet habitat parameters from
existing databases .
21 March 2012
Alan Burger
aburger@uvic.ca
Ph: 250-378-2468
1. GENERAL BACKGROUND
The objective was to extract data from several existing data sources to provide summaries
of habitat indices useful for management of forests (e.g., determining the suitability of
potential Wildlife Habitat Areas, or the effects of logging a particular stand of forest).
The data were meant to complement other indices of habitat suitability, such as
algorithms based on forest cover data, air photo interpretation and low-level aerial
surveys, and provide ground-based measures of habitat suitability.
Data were drawn from multiple studies of murrelet habitat done over the past 20+ years.
Most data were derived from plots or transects. There were three primary sources:
i) Tree Database - the tree database assembled in 2009 in order to study factors affecting
the development of potential nest platforms (see Burger et al 2010 for details) – these
data were from many parts of the BC coast and had been previously archived in the SPI
system.
ii) MFLNRO data – provided by Connie Miller-Retzer and Tanya Dunlop. Data from
plots done in the 1990s and early 2000s related to forest management on SW Vancouver
Island. Because most of these plots sampled only trees  80 cm DBH, the tree data were
not combined with the previous tree data set.
iii) WFP data – provided by John Deal of Western Forest Products, these were data from
studies done by Deal and Bill Harper for CanFor in the later 1990s and early 2000s,
mainly in the Nimpkish landscape unit on Vancouver Island. The data included came
from the transect file provided by John Deal. There were no individual tree data from
these WFP transects. Because they overlapped in space an provided duplications, the plot
data provided by WFP were not included in the analysis.
See section 6.3 for references to published papers and reports related to these data.
2. FINAL PRODUCTS
The data are included in several Excel spreadsheets;
i) MaMu Platforms Tree & Plot 2012_03_21.xlsx - this contains the Tree Database data
for both individual trees and summarized by plots or transects – includes data from all
parts of the BC coast;
ii) AllTreeDataMFLNRO_2012-03-05.xlsx - this is the MFLNRO data formatted for
individual trees and (in the SUMMARY sheet) calculated for each plot or transect;
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iii) JD_mamu_transects 2012-03-09.xlsx – this has the transect data from WFP reformatted to match the data fields of the previous two files.
iv) MaMu_Platforms_VI_Combined_2012-03-21.xlsx – This contains the combined data
from all three data sources for Vancouver Island. Some of the data were cut from this file
if there were no plot areas available or if measures came from single trees (see details
below).
v) Streamlined VI data for GIS work (has the non-esstential parameters stripped out):
MaMu_Platforms_GIS_2012-03-21.xlsx
The following are notes made in the work with each data source.
3. NOTES FROM THE BC-COAST TREE DATABASE
3.1. Plot and Transect areas and calculating densities
Plot or transect area in ha was derived from the original data sets or reports.
a) Removal of sites with single trees
All sites which had a single tree were deleted – there were many samples which were not
from plots or transects (nest trees and trees sampled as lone trees) which could not be
used for showing platform densities etc.
b) Burger UVic and MOE Clayoquot Sound data
These were all sampled in standard 30x30 m plots (0.09 ha).
c) Plot areas on Haida Gwaii (see also Appendix 1)
Plot areas were provided by Irene Manley and Alvin Cober – see Excel file:
Manley_plot_areas_5March2012.xls
Notes from Irene Manley: All the sites in the files you attached are 30x 200m transects
(SS01 to SS26, SS30 to SS60, HW01 to HW33 and GR01 to GR32).
It sounds like there was some variation in the spatial references available but these
platform and platform tree data are all from transects. The other data on cards would
pertain to smaller plots within the transect. Hope this helps- Irene
d) Manley plots from the South Coast region
Plot areas were provided by Irene Manley – see Excel file:
Manley_plot_areas_5March2012.xls
Many of the sites with only 1 tree were nest trees that were sampled separately (n1, n2,
n3…. Etc) – these were excluded from the platform density data.
Irene Manley: Plots with A and B were edge interior paired plots in the same stand A =
edge and B interior.
Manley’s data used two methods:
a) 25 m radius circular plots
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b) 30 x 200 m transects
these were labeled and areas calculated based on Manley’s notes in March 2012.
e) Plot areas in the SFU data
Mike Silvergieter, who collated the SFU tree data, calculated the plot area for each
sample site (Excel spreadsheet: SFU plot size fr Silvergieter.xls)
Most of the SFU sites used in this analysis used the same protocol as Manley – a 25 m
radius circular plot.
Notes from Mike Silvergieter:
Here is the plot size I had calculated in square metres.
Remember that "SFU" protocol did not count potential platforms, and because of the
small subplots it often measured very few canopy trees. I ended up throw in out sites with
less than 5 trees since a subsampling exercise found so few trees did not represent the
area.
The SFU protocol measured the three nearest canopy trees to a central tree (so the centre
plot area varied- I calculated that using the farthest tree as the radius) and 12 additional
3m-radius plots up to 75m out.
Many of those were inaccessible and that I also took into account in the area.
Some of the RIC plots (25m radius) were also partial and that is reflected in the data as
well.
f) SFU data from Josh Malt
Many of the SFU data (31 sites in Nimpkish, WNVI; 18 sites around Desolation Sound,
SC) come from the study of Malt (2007; see also Malt and Lank 2007, 2009). Here the
plots were made at edge and interior sites (site labels have xxx-e and xxx-I, respectively).
See Malt 2007 page 65 for details: he measured 10 canopy trees within a 25 m radius, and
then also “Within each plot, we counted the total number of canopy trees with at least one
potential platform”. The 10 trees cannot be used to estimate platform or tree densities but
the remaining plots with 12-162 trees probably reflect densities of trees with at least one
platform.
This was confirmed by e-mail (9 March 2012) from Josh Malt:
For the most part, I think you’re right, as most of the measurements we took were only on
10 randomly selected trees. However, we also collected number of platform trees per
plot: n “Within each plot, we counted the total number of canopy trees with at least one
potential murrelet platform” (Habitat methods within chapter 3 of my thesis). We
calculated and used “platform tree density” metric in our analyses (see figure 3.3., as well
as results in our recent paper- Northwest Science 85: 549). So I can send you that data
from my thesis work, although it will probably take me a while to dig it up (and it will
have to wait until after I get back from vacation on March 22). For the habitat data from
the post-thesis work (i.e. from Squamish area, and southwest Vancouver Island) you’ll
have to talk to Jason or Mike. As far as the list you gave, it is possible that in the first
3
year in desolation sound (and/or after my thesis) that this additional data was collected. I
can also take a look for that within what I have.
3.2. Checking data
Because there was a lot of manipulation of these data in getting to the plot densities I did
a cross-check of the calculated densities, comparing measures like tree density, platform
density, mean DBH and other parameters with the original reports or source data. These
sources were checked:
 Burger et al. 2000a. For EVI data (Burger, A. E., V. Bahn and A. Young. 2000.
Assessment of nesting habitat for Marbled Murrelets in coastal Douglas-fir forests
of southeast Vancouver Island in 1998 and 1999. Unpublished report, University
of Victoria, Dept. of Biology.)
 Burger et al. 2000b for Carmanah and Coast data (Burger, A. E., V. Bahn and A.
R. M. Tillmanns. 2000. Comparison of coastal fringe and interior forests as
reserves for Marbled Murrelets on Vancouver Island. Condor 102:915-920.)
 Rodway & Regher 2002 for Clayoquot data (Rodway, M. S., and H. M. Regehr.
2002. Inland activity and forest structural characteristics as indicators of Marbled
Murrelet nesting habitat in Clayoquot Sound. Pp. 57-87 in Multi-scale studies of
populations, distribution and habitat associations of Marbled Murrelets in
Clayoquot Sound, British Columbia (A. E. Burger and T. A. Chatwin, eds.).
Ministry of Water, Land and Air Protection, Victoria, BC.
Mean values were generally identical or similar to those in the original reports. In some
cases some of the original data had been cut or additional plots added so comparisons
were not always expected to give identical results. No obvious problems were found.
4. NOTES FROM THE MFLNRO DATA
General – I did the analysis in small steps and at each stage checked the data to see if the
values coming out were reasonable, looked for outliers as indicators of possible errors.
Points 4.1 to 4.12 cover the work done with the individual tree data, the remaining points
cover some of the tree data but mostly the plot and density conversions.
4.1. Missing data
 I filled in a period (.) for the missing data for most of the fields we are likely to
use.
 For canopy stratum I estimated from the tree height and the heights of the other
trees in the plot whether it was a canopy, subcanopy (generally those <25 m) or
emergent ( 50m).
 I assumed none of these were a known nest tree (i.e. gave them all code 0).
4.2. Plot area – was calculated in hectares.
4.3. Elevation – the missing data here should be fairly easy to find using the UTM
location. I no longer have any programs that will do that but it would be worth doing
since elevation is often an important parameter for MaMu habitat.
Slope and aspect might be found from GIS topographic maps in the same way.
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4.4. Slope
Slopes were converted from % to the standard forest classification codes:
Slope
slope
slope
code
(%)
(degrees)
0
0-10
0 - 5.7
1
11-20
5.8 - 11.3
2
21-30
11.4 - 16.7
3
31-40
16.8 - 21.8
4
41-50
21.9 - 26.6
5
51-60
26.7 - 31.0
6
61-70
31.1 - 35.0
7
71-80
35.1 - 38.7
8
81-90
38.7 - 42.0
9
91-100
42.1 - 45
4.5. Aspect – degrees were converted into the 8 major compass bearings.
Valley location was converted to L – lower third; M – mid third; U – upper third. Very
few data have these values.
4.6. Productivity (Produnit)
Not many of the records have BEC site series but for those that do I looked up the
productivity from Green and Klinka (1994; section 6.3).
4.7. Very large trees with no numerical DBH
For trees with DBH given as 200+ (28 trees), 300+ (about 6 trees) and 400+ (1 tree) I
converted these to 210, 310 and 410 cm, respectively. Otherwise they would not be
included in any numerical analyses. I made a note of the original DBH recording in the
comments section.
4.8. Method to measure tree height – I assume it was all ME – measure some and
eyeball the rest.
4.9. Stratum. Some of the data were labeled A1, A2 and A3. From the biogeoclimatic
and soil classification systems:
Al: Dominant Trees
Al: A2: Main Canopy
A3: Trees
Based on tree height taller A1 trees ( 50 m) were labeled as Emergents (E).
4.10. Snags
I labeled all the snags in the snag column based on the comments.
This was tricky because there is obviously a lot of variation in what different people were
calling snags. Some snags had mistletoe scores of 5 and 6! One snag had 18 platforms. I
did not consider those trees labeled as snaggy or snags with branches to be true snags. I
will leave all the snags out of analyses for platform density.
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4.11. Epiphyte thickness.
Many of the records used the old A,I,B system (but without considering the I
intermediate) instead of the numerical 0, 1, 2, 3 system. It also seems that some records
have A as thin moss and B thick whereas others have it the other way around. Overall it
seems, when comparing these alphabetical scores that A corresponds to 1 or 2 and B
corresponds to 2 or 3. I assigned the numerical score depending on both the alphabetical
score and the extent of epiphyte cover (one seldom gets thick mats when the cover is 1
(trace) or even 2 (1-33%). I wouldn’t put any weight on the epiphyte thickness ratings for
these data. This is how I derived a numerical score:
Epiphyte cover
Thickness = A
Thickness = B
0 – none
0
0
1 – trace
1
1
2 – 1-33%
2
2
3 – 33-66%
2
3
4 – 66-100%
2
3
I also adjusted a few records that were almost certainly errors (epiphyte cover = 0 or 1
and thickness = 3).
4.12. Platform numbers converted to PLATCODE
We found that there was a lot of variation among observers in assessing platforms and
one way to overcome this was to convert the actual platform count into a more
compressed geometrically scaled score:
0 = 0 platforms; 1 = 1 platform; 2 = 2-5; 3 = 6-10; 4 >10.
I have a little Excel macro that does this easily.
4.13. UTM
Checked all UTM locations – no variation found within each plot location.
Created base for plot summaries
4.14. Mean values
Used pivot table to calculate mean values or other parameters. I did not bother with those
fields where there was very little data (age class, height class etc.).
4.15. Tree density.
Range is 18.0 to 152.0 trees per ha. Scanning through these densities the only one which
appears to be a real outlier is No Name Lakes NN# with 152 trees/ha. I highlighted this.
It might be worth checking to see if the area of the plot and tree number are correct.
Since many plots considered only larger trees (>80 cm DBH) these tree densities are
rather meaningless and not comparable with densities derived from the original tree
database.
4.16. Removal of snags.
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To be consistent with previous analyses (Burger et al. 2010) I excluded snags from all
subsequent analyses. In labeling snags I did not include those labeled as “snaggy” or
“snags with branches’ since some of these had platforms.
Some of the plots seem to have a lot of snags: Plot Klanawa_MAMU_B, TFL6-plot_205,
TFL6-plot_130-2. These are highlighted. Probably not a problem but might be worth a
second look at the snag labels.
4.17. DBH and Tree height.
Many of the plots sampled only the larger trees (>80 cm DBH). I calculated overall mean
DBH and tree height but these are not comparable with the original tree database.
The mean values for both DBH (112 cm) and Tree Height (40.8 m) are exceptionally
high. For contrast I calculated the overall mean for WNVI and EVI in the original tree
data: 46.0 cm and 25.0 m (N = 17,848 trees). Obviously most of the smaller trees were
not included in the MFLNRO data. Some sites like CA-3 have only trees >1 m DBH
included – obviously even the mid-sized and quite large trees were excluded in this plot.
Combining these tree data with the original database is therefore going to cause
problems and I recommend leaving them separate. We really need a detailed
description of the protocol used for these transects to be included along with the
data so users of this file know exactly what was done in the field for each plot.
To facilitate this process I set up a column showing the minimum DBH in each plot
(mostly 80 cm) to quickly identify those plots where there are only data from the biggest
trees.
4.18. Trees with DBH >60 cm.
The analysis by Burger et al. (2010) showed that for most regions of BC trees began to
get platforms when they were >60 cm DBH. I therefore calculated the density of trees
>60 cm per ha for each plot as an indicator of large trees likely to provide platforms. This
is actually meaningless with these data since most plots only included trees >80 cm. I
was going to delete these data.
4.19. Trees with DBH>80 cm.
Since most of the plots included only these big trees I selected this size for all plots.
Density of trees with DBH>80 cm is a good index of the availability of large trees.
4.20. Platforms and trees with platforms.
I calculated several parameters here:
 Density of platforms per ha (PLAT_DENSITY/ha).
 Density of trees with at least one platform per ha (PLAT_TREES/ha)
 Density of trees with two or more platforms per ha (has been used in some habitat
analyses on Vancouver Island) (PLAT2_TREES/ha)
Just for interest I calculated that 87% of all platforms were in trees with 2 platforms and
only 13% in trees with just one platform. Overall 29.2% of trees had only 1 platform and
70.8% had 2 or more.
4.21. Epiphyte cover and thickness, and Mistletoe
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I calculated:
 Mean epiphyte cover
 Mean epiphyte thickness
 Mean mistletoe score
4.22. Tree species.
There is evidence (Burger et al. 2010) that some species (Sitka Spruce, Hemlocks in
lower elevations, Yellow Cedar in higher elevations) are more likely to produce
platforms than others (W red-cedar is usually poor unless v large). I calculated the
number and density of likely species with DBH>80 using these criteria
(LIKELY_SP_TREE; LIKELY_SP/ha). I feel this measure is less likely to be really
useful since the major difference in platform development among the tree species seems
to occur at smaller diameters (see Fig. 3 in Burger et al. 2010). For interest I calculated
that 42% of the trees with DBH>80 cm were the likely species.
5. NOTES ON THE DATA FROM WESTERN FOREST PRODUCTS (JOHN DEAL)
Excel file: JD_mamu_transects.xlsx
5.1 Background
These data were originally collected in 1999-2003 by Canadian Forest Products in
the Nimpkish area of northern Vancouver Island (WNVI MaMu region). Some
descriptions of data in reports by Harper et al. (2001a,b,c, 2004). John Deal and Bill
Harper provided help in interpreting the data fields.
See Harper et al. (2001c) p. 12-16 for some explanations of data codes and criteria:
Platforms were defined as limbs 15 m above ground with moss or limbs 15 cm in
diameter.
Platforms were separated into those occurring on large trees ( 80 cm DBH) or
smaller trees (<80 cm DBH).
Large tree platforms per ha: this means numbers of platforms per ha in trees  80
cm DBH.
5.2 Productivity units
These were derived from the BEC variants and site series using Green and Klinka
(1994, pp. 197-215). Where there were more than one site series shown within the
same transect the average productivity score was used but rounded (higher) to a
whole number.
5.3 Data not in these files
The following parameters were not in the data files received:
 Plot dimensions and area (but not needed since critical data were given as
densities per ha)
 Age class of the stand (AGECL)
 Height class of the stand (HTCL)
 Location in the valley (Valloc)
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



Density of all trees & snags (DENS_stem
Density of live trees (DENS_livetrees)
Mean DBH of all live trees (DBH_mean)
Mean height of all live trees (HT_TREE_mean)
5.4 Additional useful parameters
The data provide a range of additional measures not calculated in the other platform
analyses. These are shown in with red highlighting on the column headers and
explained in the Codes sheet.
5.5. Data checking
After collating the data, pivot tables were used to check for errors by comparing the
results with the tables in Harper et al. (2001c). All matched perfectly.
5.6. References to reports
see below section 6.3
6. NOTES ON THE FINAL VANCOUVER ISLAND PLATFORM DATABASE
6.1. Mean DBH.
This is potentially a useful measure but has to be applied with caution since in some
plots and transects only large trees (e.g., >80 cm DBH or in some cases “canopy
trees”) were included and this will obviously skew the average. The column
Minimum tree size can be used to exclude those plots with only large trees, if
desired. I left this out of the final GIS database for this reason.
6.2. Landscape Units
In the WFP (Deal) data they have Landscape Units as well as Watersheds. Both
seem useful but it would be clumsy to make a whole new data field just for LU, so I
combined them into one column:
Lower Nimpkish
Atluck
Lower Nimpkish - Atluck
6.3 References for the various data sources.
It is almost impossible to assign data from a particular plot/transect to an individual
report or publication. Some of the data have not been cited in reports and some data
have been used in several publications.
MFLNRO_Miller-Retzer
Data collected by the then Ministry of Environment for Connie Miller-Retzer.
Giesbrecht, T. and R. Walker. 2001. Marbled Murrelet Dawn Terrestrial Survey of
TFL 44, 2001. Unpubl report prepared for BC Ministry of Sustainable Resource
Management, Port Alberni, B.C.
Grundmann, E. 1998a. MAMU Habitat '98 Corrigan LU. Unpublished report.
Grundmann, E. 1998b. MAMU Habitat '98 Toquart LU. Unpublished report.
9
Kremsater, L., H. Davis, & D. Byng. 1999. Developing GIS Algorithms to Predict
Black-tailed Deer Winter Range, Elk Winter Habitat, Marbled Murrelet Nesting
Habitat, and Black Bear Habitat in TFL #6. Prepared for Western Forest
Products.
Lindsay, D., & S. Leigh-Spencer. 1998. Marbled Murrelet Nesting Habitat Evaluation
of TFL 46.
Schroeder, B.K. 2000. Technical Report for the Ministry of Environment, Lands and
Parks Marbled Murrelet Project, 2000. Unpublished Report.
Schroeder, B.K. 2001a. Cameron Landscape Unit Habitat Transect plot Summary and
Notes. Unpublished report.
Schroeder, B.K. 2001b. Effingham Landscape Unit Habitat Transect plot Summary
and Notes. Unpublished report.
Schroeder, B.K. 2001c. Marbled Murrelet Presence/Not Detected Inventory: Barkley
Sound 2001. Unpublished report.
Schroeder, B.K. 2001d. Sproat Landscape Unit Habitat Transect plot Summary and
Notes. Unpublished report.
Schroeder, B.K. 2001e. Weyerhaeuser Marbled Murrelet Presence/Not Detected
Investigation, Mount Rosander 2001. Unpublished Report.
Schroeder, B.K. and C. Henderson. 2001. Marbled Murrelet Presence/Not detected
Inventory, Barkley Sound 2001. Unpubl. Report to B.C. Ministry of
Environment. Bernard K. Schroeder Consulting, Nanaimo. B.C.
Tripp, T., & S. Willmott. 2002. TFL 19 Wildlife Management Part II: Marbled
Murrelet Activity and Habitat Surveys for TFL19, Vancouver Island 2001.
Prepared for Western Forest Products.
Veach-Sinclair, L. 2000. Marbled Murrelet Nesting Habitat Evaluations in TFL 44 –
Weyerhaeuser. Unpublished report.
Webster, S. 2000. Technical Report for the MELP / Weyerhaeuser West Island
Timberlands Marbled Murrelet Project. Unpublished report.
MOE_Chatwin
Ministry of Environment data from the 1995-1998 in Clayoquot Sound study run by
Trudy Chatwin of the BC Ministry of Environment. Publications using these data and
explaining the methods:
Bahn, V., and D. Newsom. 2002a. Can marbled murrelet use of nesting habitat be
predicted from mapped forest characteristics? Pp. 89-99 In: Multi-scale studies
of populations, distribution and habitat associations of marbled murrelets in
Clayoquot Sound, British Columbia (A. E. Burger and T. A. Chatwin, eds.).
Ministry of Water, Land and Air Protection, Victoria, BC. URL:
http://env.gov.bc.ca/wld/documents/techpub/mamuwebs.pdf
Bahn, V., and D. Newsom. 2002a. Habitat suitability mapping for Marbled Murrelets
in Clayoquot Sound. Pp. 101-119 in Multi-scale studies of populations,
distribution and habitat associations of Marbled Murrelets in Clayoquot Sound,
British Columbia (A. E. Burger and T. A. Chatwin, eds.). Ministry of Water, Land
and Air Protection, Victoria, BC.URL:
http://env.gov.bc.ca/wld/documents/techpub/mamuwebs.pdf
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Burger, A. E. and T. A. Chatwin (eds.). 2002. Multi-scale studies of populations,
distribution and habitat associations of Marbled Murrelets in Clayoquot Sound,
British Columbia. Ministry of Water, Land and Air Protection, Victoria, BC.
Available at: http://env.gov.bc.ca/wld/documents/techpub/mamuwebs.pdf
Rodway, M. S., and H. M. Regehr. 2002. Inland activity and forest structural
characteristics as indicators of Marbled Murrelet nesting habitat in Clayoquot
Sound. Pp. 57-87 in Multi-scale studies of populations, distribution and habitat
associations of Marbled Murrelets in Clayoquot Sound, British Columbia (A. E.
Burger and T. A. Chatwin, eds.). Ministry of Water, Land and Air Protection,
Victoria, BC. URL:
http://env.gov.bc.ca/wld/documents/techpub/mamuwebs.pdf
MOE_HG
Data provided by Alvin Cober of MFLNRO collected by Ministry of Environment for
management of Marbled Murrelets on Haida Gwaii. Details available from Irene
Manley (contractor for most of the surveys) and Alvin Cober. Some early work was
summarized in this publication:
Manley, I. A., A. Harfenist, and G. Kaiser. 2001. Marbled Murrelet telemetry study on
Queen Charlotte Islands/Haida Gwaii. Unpublished report, Ministry of
Environment, Lands and Parks, Skeena Region, Smithers, BC.
McLennan, D., V. Veenstra and I. Manley. 2000. Preliminary landscape-level habitat
suitability algorithms for Marbled Murrelet and Queen Charlotte Goshawk on
the Queen Charlotte Islands/Haida Gwaii. Report to Ministry of Environment,
Lands and Parks, Smithers, BC. Oikos Ecological Services Ltd., Smithers, BC.
SFU
Data were from various studies related to known nest sites, audio-visual surveys
and other purposes. Provided by Dr. David (Dov) Lank and Michael Silvergieter.
These data were first collated by Silvergieter to be used in the tree database (see
Burger et al. 2010 cited below). Other publications:
Silvergieter, M. P. 2009. Multi-scale analyses of nest site selection and fledging
success by marbled murrelets (Brachyramphus marmoratus) in British
Columbia. MSc. Thesis, Department of Biological Sciences. Simon Fraser
University, Burnaby, BC.
SFU_Manley
Work done by Irene Manley for her SFU thesis and other related work – mostly on
the South Coast region
Manley, I. A. 1999. Behaviour and habitat selection of Marbled Murrelets nesting on
the Sunshine Coast. M.Sc. Simon Fraser University, Burnaby, B.C.
Manley, I.A , and T. Jones. 2000. Options for managing the nesting habitat of marbled
murrelets in the Sunshine Coast Forest District. Unpublished report, Ministry
of Environment, Lands and Parks, and International Forest Products, Surrey,
BC.
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Manley, I.A., F. L. Waterhouse, and A. S. Harestad. 1999. Nesting habitat of Marbled
Murrelets on the Sunshine Coast. Forest Research Extension Note EN-002, BC
Forest Service, Nanaimo, BC. 7 p. (Available at
http://www.for.gov.bc.ca/vancouvr/research/wildpub.htm)
SFU_Malt
These data were collected by Joshua Malt for his thesis on edge effects and Marbled
Murrelets. References:
Malt, J. M. 2007. The influence of habitat fragmentation on Marbled Murrelet
(Brachyramphus marmoratus) habitat quality in southwestern British
Columbia. MSc Thesis, Simon Fraser University, Burnaby, B.C.
Malt, J. M. and D. B. Lank. 2007. Temporal dynamics of edge effects on nest predation
risk for the Marbled Murrelet. Biological Conservation 140: 160-173.
Malt, J. M. and D. B. Lank. 2009. Marbled Murrelet nest predation risk in managed
forest landscapes: dynamic fragmentation effects at multiple scales. Ecological
Applications 19(5): 1274–1287.
UVic_Burger
Data from various studies by Alan Burger and his students and collaborators at
University of Victoria. Publications using these data and explaining the methods
(available online at http://web.uvic.ca/~mamu/mamu-publications.html):
Burger, A. E. and V. Bahn. 2004. Inland habitat associations of Marbled Murrelets on
southwest Vancouver Island, British Columbia. Journal of Field Ornithology
75:53-66.
Burger, A. E., V. Bahn and A. R. M. Tillmanns. 2000. Comparison of coastal fringe and
interior forests as reserves for Marbled Murrelets on Vancouver Island. Condor
102:915-920.
Burger, A. E., V. Bahn and A. Young. 2000. Assessment of nesting habitat for Marbled
Murrelets in coastal Douglas-fir forests of southeast Vancouver Island in 1998
and 1999. Unpublished report, University of Victoria, Dept. of Biology.
Burger, A.E., R.A. Ronconi, M.P. Silvergieter, C. Conroy, V. Bahn, I.A. Manley, A. Cober,
and D.B. Lank. 2010. Factors affecting the availability of thick epiphyte mats
and other potential nest platforms for Marbled Murrelets in British Columbia.
Canadian Journal of Forest Research 40(4): 727-746.
WFP_Deal
These data were provided by John Deal of Western Forest Products. The data were
collected in 1999-2003 by Canadian Forest Products in the Nimpkish area of
northern Vancouver Island (WNVI MaMu region). John Deal and Bill Harper (Osiris
Wildlife Consulting, Victoria) provided help in interpreting the data fields.
References relating to these data:
Harper, W. L., J. M. Cooper, and P. Chytyk. 2001a. Marbled Murrelet nesting habitat
in the draft Lower Nimpkish landscape unit, Vancouver Island: final report.
Unpublished report, Canadian Forest Products Ltd., Woss, BC.
Harper, W. L., J. M. Cooper, and P. Chytyk. 2001b. Marbled Murrelet nesting habitat
in the draft Upper Nimpkish landscape unit, Vancouver Island: year 2 progress
12
report and preliminary assessments. Unpublished report, Canadian Forest
Products Ltd., Woss, BC.
Harper, W. L., J. M. Cooper, and P. Chytyk. 2001c. Preliminary landscape model of
Marbled Murrelet nesting habitat in the Nimpkish Valley, Vancouver Island.
Unpublished report, Canadian Forest Products Ltd., Woss, BC.
Harper W.L., B.K. Schroeder and T. Tripp. 2004. Marbled Murrelet nesting habitat
surveys in TFL 37: 2003 transects and comparison with helicopter
reconnaissance mapping. Unpublished FIA report by Osiris Wildlife
Consulting, Victoria, BC for Canadian Forest Products Ltd., Woss, BC. 31 pp.
6.4. A few other things to check.
 I noticed that one of the MFLNRO plots has no UTM location (TFL6-plot_31)
7. NOTES – DERIVING PLATFORMS PER HA IN ONLY LARGE TREES >80 CM DBH
New data column labeled D_Plat80+ (density of platforms in trees with DBH 80 cm
or larger)
7.1. From larger BC-coast sample
a) This was calculated from the Tree data and included in the SUMMARY sheet in the
file: MaMu Platforms Tree & Plot 2012_03_21.xlsx
b) the VI material was then transferred to the file:
MaMu_Platforms_VI_Combined_2012-03-21.xlsx
7.2. From the MFLNRO data from Miller-Retzer
This was copied from the regular column D_Plat because all the trees sampled were
>80 cm
(Tanya – you will have to check that this is correct)
7.3. For the WFP data from John Deal
This was already in their data under the column PLAT_LARGE and was simply
copied over into the new column.
8. NOTES ON RETENTION OF DATA IN THE STREAMLINED GIS VERSION.
File: MaMu_Platforms_GIS_2012-03-21.xlsx
8.1. Deleting incomplete records:
 691 plots or transects in the original database
 133 plots from SFU and SFU_Malt removed because they sampled 10 trees
and did not provide density measures (no plot area)
 20 of the WFP_Deal sites were deleted because they lacked sufficient data.
 538 plots or transects remaining.
8.2. Deleting less useful parameters
13
I included parameters most likely to be used as habitat quality indicators. Some
potentially useful indicators were omitted because there were too few records. See
the table below for rationale for including or excluding parameters.
14
Table 1. Rational for including or excluding parameters from the GIS platform database.
No.
% of
Parameter
records
total
Used in the GIS platform database
Elevation
491
91.3
Yes – can be used to rapidly exclude high sites
SlopeCode
472
87.7
No – not a consistent predictor of habitat quality
Aspect
463
86.1
No – not a consistent predictor of habitat quality
BECsub
460
85.5
No – not a consistent predictor of habitat quality
S_series
460
85.5
No – not a consistent predictor of habitat quality
Produnit
433
80.5
Yes relatively low occurrence in the data but a
good indicator of tree growth
CRNCLOS
431
80.1
No – not a good habitat indicator
AGECL
328
61.0
No – low coverage and most in age 8 or 9
anyway
HTCL
383
71.2
No – should be available in FC or V
Valloc
383
71.2
No – not a consistently good habitat indicator
#tree+snag
461
85.7
No – used to calculate density
D_stem
459
85.3
No – not a good habitat indicator
#snags
355
66.0
No – not a good habitat indicator
#LiveTr
461
85.7
No – used to calculate density
D_livetree
459
85.3
No – not a good habitat indicator
DBH_mean
461
85.7
No - too many from plots with only trees >80 cm
included
DBH_min
461
85.7
No – included to show which plots had only big
trees
HT_mean
461
85.7
No - too many from plots with only trees >80 cm
included
#trees60+
461
85.7
No – used to calculate density
D_tree60+
459
85.3
No – more data for trees >80 cm DBH
#trees80+
461
85.7
No – used to calculate density
D_tree80+
536
99.6
Yes - shows density of large trees >80 cm DBH
PLAT_SUM
461
85.7
No – used to calculate density
D_Plat
536
99.6
Yes - density of platforms per ha
EPICOV_mean
538
100.0 Yes - an index of moss development
EPITHK_mean
461
85.7
Yes - an index of moss development
MISTL_mean
434
80.7
No - mistletoe not a major source of nest sites in
BC
#PLAT_TREES
461
85.7
No – used to calculate density
D_PlatTree
459
85.3
Yes - density of trees with 1 or more platforms
#PLAT2_TREES
461
85.7
No – used to calculate density
D_Plat2Tree
459
85.3
Yes - density of trees with 2 or more platforms
#Likely_Sp
461
85.7
No - tree species is usually only of secondary
concern for MaMu nesting and platform
availability
D_LikelySp
459
85.3
No - see note on tree species above
#LIKELY_60+
383
71.2
No - see note on tree species above
D_Likely60+
381
70.8
No - see note on tree species above
#LIKELY_80+
461
85.7
No - see note on tree species above
D_Likely80+
459
85.3
No - see note on tree species above
Further adjustments can be made as needed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Appendix 1. NOTES FROM IRENE MANLEY ON THE HAIDA GWAII
TRANSECTS
(extracted from McLennan, D., V. Veenstra and I. Manley. 2000. Preliminary landscapelevel habitat suitability algorithms for Marbled Murrelet and Queen Charlotte Goshawk
on the Queen Charlotte Islands/Haida Gwaii. Report to Ministry of Environment, Lands
and Parks, Smithers, BC. Oikos Ecological Services Ltd., Smithers, BC.).
3.2 FIELD SAMPLING METHODS
The general approach to field sampling was to establish 30m x 200m transects within a
representative area of targeted forest cover polygons, to describe physiographic
characteristics
(slope, aspect, elevation, parent materials), biogeoclimatic site series, general forest stand
structure, and forest structure attributes specific to Marbled Murrelet and Queen Charlotte
Goshawk habitat suitability. Sampling teams included specialists in ecology and stand
structure,
as well as Marbled Murrelet and Queen Charlotte Goshawk specialists.
3.2.1 Establishment of Sample Transect Strips
Sample transects 200m long and 30m wide (0.6 ha) were established within forest cover
polygons
by walking into the polygon for at least 70m to a point where stand characteristics
represented the
stand within the polygon (Figure 2). The starting point for the transect was determined by
using a
random number process to select a distance (within 10m) and bearing to the transect
starting
point. The closest suitable tree to that point was selected as the transect point of
commencement
(POC). The POC tree was clearly flagged, and an aluminum plate was attached, labeled
with the
project name, and with the transect number, distance, and bearing. The bearing for the
long axis
of the transect was oriented parallel at the longest dimension of the forest cover polygon.
Transects were laid out using a compass and hip chain with double flagging hung at a
minimum
of every 25m along the transect, and distance marked on the tape to help reference the
locations
of potential Marbled Murrelet nest trees. Any additional flagging required due to
visibility
problems was a single flag.
Figure 2: Schematic of sample transect used in the project. The diagram depicts a
transect that
includes two sites series.
3.2.2 Forest Ecosystem Sampling
All unique site series encountered along the sampling transects were described using RIC
(1998)
16
Ground Inspection Forms (GIFs), following codes and protocols outlined in DEIF (1998).
Information collected included site series, stand structural stage and modifiers, landform,
humus
form, soil texture, and a comprehensive list of plant species. GIF plot locations were
noted on the
transect maps for each polygon sampled so that the habitat data can be related directly to
the
ecosystem and stand structural data. The distributions of all site series-stand structural
stage
combinations along the sample strip were mapped on transect paper (see Figure 2).
3.2.3 Stand Sampling
Four variable radius prism plots with small fixed area subplots were established at 50m
intervals
(25m, 75m, 125m, 175m) along the sample strip, to provide a description of stand
structure.
Basal area factors (BAFs) of cruising prisms were selected so that between 8 and 12 'in'
trees
were captured at each point. Sweeps accounted for slope on steep ground. For all healthy
'in'
trees breast height diameter (DBH) was measured, and canopy position and species
noted. For
snags, DBH, canopy position, species, and tree appearance were evaluated. Seedlings and
saplings (<7.5cm dbh) and poles (7.5-17.5cm dbh) were counted by species in fixed
radius
subplots centred on the centre for the prism plots. At least one codominant 'in' tree was
sampled
for height and age in each variable radius plot. Height estimates were calculated
immediately in
the field and used to calibrate height estimates for the Marbled Murrelet sample trees.
3.2.4 Marbled Murrelet Habitat Suitability Sampling
Marbled Murrelet habitat suitability data was collected according to RIC (1997) methods,
except
for plot size and shape, as described above (Figure 2). The use of a transect strip instead
of a plot
allowed for a wider sample of sometimes sparsely or patchily distributed platform trees.
Evaluation and measurement of all suitable Marbled Murrelet nest trees was carried out
within
the 200m x 30m transect strip. Based on a visual evaluation while the transect centre line
was
being laid out, if it was estimated that there would be more than 60 nest trees in the
sample
transect, only one side of the transect was assessed for Marbled Murrelet nest trees. This
adjustment was made to speed up the sampling process when sample transects had high
densities
of nest platforms. For borderline trees, the distance from the transect centre line to the
17
middle
point at breast height of the potential sample tree was measured to ensure the tree fell
within the
sample strip. A tree that contained at least one suitable nesting platform was considered a
sample
tree, and species, diameter, height, platform density, epiphyte cover and mistletoe
infestation
were collected, following RIC (1997). Potential nesting platforms were broken into two
categories - 12-18 cm and >18cm in diameter. The smaller diameter platforms were
described for
the first field trip only. Each potential nest platform was classified into one of several tree
morphology categories, and diameter class, moss cover and moss thickness were
estimated.
3.2.5 Queen Charlotte Goshawk Habitat Suitability Descriptions
Queen Charlotte Goshawk habitat suitability was assessed at all ecosystem sample plots
to
provide correlation with the forest cover types and site series units, and to describe Queen
Charlotte Goshawk habitat suitability over the area occupied by each site series within
the sample
transect strip. At each assessment site a Wildlife Habitat Assessment (WHA) Form
(DEIF 1998)
was completed. Quality control and calibration for the Queen Charlotte Goshawk habitat
assessments was provided by Don Doyle MELP Nanaimo.
Irene Manley- Wildlife Biologist
Fish & Wildlife Compensation Program (FWCP)
103-333 Victoria St Nelson, BC V1L 4K3
ph: 250 352-6874 email: irene.manley@bchydro.com
www.fwcp.ca
18