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Appendix 1. Population estimates at occupied sites in British Columbia

Table A1. Population estimates at four currently occupied locations in British Columbia, based on egg mass counts. Note that sampling intensity does vary across years.
Extant locationPopulation YearTotal number of egg massesNumber of communal oviposition sitesEstimated number of breeding adults
Maintenance Detachment Aldergrovea1997904180
Maintenance Detachment Aldergrovea200029658
Maintenance Detachment Aldergrovea200131662
Maintenance Detachment Aldergrovea200234768
Maintenance Detachment Aldergrovea2003b12524
Maintenance Detachment Aldergrovea200410420
Maintenance Detachment Aldergrovea20057414
Maintenance Detachment Aldergrovea20068616
Maintenance Detachment Aldergrovea2007000
Maintenance Detachment Aldergrovea2008000
Maintenance Detachment Aldergrovea2009001 adult male observed
Maintenance Detachment Aldergrovea2010000
Mountain Slough199716232
Mountain Slough200043486
Mountain Slough2001c7012140
Mountain Slough2002c967192
Mountain Slough2003545108
Mountain Slough2004626124
Mountain Slough200549898
Mountain Slough2006NAdNAdNAd
Mountain Slough200737NAd74
Mountain Slough2008505100
Mountain Slough200945890
Mountain Slough20105213104
Maria Sloughe199738376
Maria Sloughe2000753150
Maria Sloughe20017110142
Maria Sloughe20021447288
Maria Sloughe2003f1276254
Maria Sloughe20041175234
Maria Sloughe20051254250
Maria Sloughe200699NAd198
Maria Sloughe200721NAd42
Maria Sloughe20086710134
Maria Sloughe2009451090
Maria Sloughe201067NAd134
Morris Valley20087715154
Morris Valley2009635126
Morris Valley201039778
All Four Sites19971449288
All Four Sites200014713294
All Four Sites200117228344
All Four Sites200227421548
All Four Sites200319315386
All Four Sites200418915378
All Four Sites200518115362
All Four Sites2006g1076214
All Four Sites2007g58NAd116
All Four Sites2008h19430388
All Four Sites2009 hi15323306
All Four Sites2010h15820g316
All Four SitesAverage16417328

b Includes a count of one pair observed in amplexus. Egg mass not located.

c Incomplete survey due to lack of permission to access private properties.

d Data not available.

e Release of metamorphic Oregon Spotted Frogs back into Maria Slough (year and number): 2002 (354); 2003 (381); 2004 (836); 2007 (846); and 2008 (1012).

f Assume female frogs lay one annual clutch of eggs, and a 1:1 sex ratio.

g Data not available from at least 1 site, so numbers are minimums.

h Totals include data from the new (fourth) population (Morris Valley) discovered in 2008.

i One site with multiple single egg masses that had moved due to water fluctuations.

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Appendix 2. Site-specific threat assessment

Table A2. Threats to Oregon Spotted Frog populations in B.C. by occupied site (expanded from Hayes 1997)
Threats/Limiting factorSiteaRelative impactsbSpatial/temporal naturecCertaintyd
 1. Habitat losses caused by human activities
MDACW - CC
 1. Habitat losses caused by human activities
MTSCW - HC
 1. Habitat losses caused by human activities
MSCL - HC
 1. Habitat losses caused by human activities
MOPW - CC
 2. Hydrological alteration
MDACW - CP
 2. Hydrological alteration
MTSPW - HC
 2. Hydrological alteration
MSPW - HC
 2. Hydrological alteration
MOCW - HC
 3. Habitat losses caused by natural succession
MDAPW - CC
 3. Habitat losses caused by natural succession
MTSCW - CC
 3. Habitat losses caused by natural succession
MSCW - CC
 3. Habitat losses caused by natural succession
MOCW - CP
 4. Insufficient habitat size
MDAN (18 ha)W - EP
 4. Insufficient habitat size
MTSN (20 ha)W - EP
 4. Insufficient habitat size
MSN (16 ha)W - EP
 4. Insufficient habitat size
MONW - EP
 5. Exotic predatorse
MDAP (Bf)W - CC
 5. Exotic predatorse
MTSC (Gf)W - CP
 5. Exotic predatorse
MSC (Bf, Gf)W - CP
 5. Exotic predatorse
MOULC
 6. Exotic, invasive vegetationf
MDAPW - CC
 6. Exotic, invasive vegetationf
MTSPW - CC
 6. Exotic, invasive vegetationf
MSPW - CC
 6. Exotic, invasive vegetationf
MONLC
 7. Genetic isolation due to habitat fragmentation (distance in km to nearest occupied site)
MDACW (50)P
 7. Genetic isolation due to habitat fragmentation (distance in km to nearest occupied site)
MTSCW (7)P
 7. Genetic isolation due to habitat fragmentation (distance in km to nearest occupied site)
MSCW (8)P
 7. Genetic isolation due to habitat fragmentation (distance in km to nearest occupied site)
MOCW (7)P
 8. Risk of drought and climate change
MDACW - EC
 8. Risk of drought and climate change
MTSCW - EP
 8. Risk of drought and climate change
MSCW - EP
 8. Risk of drought and climate change
MOCW - EP
 9. Water quality
MDAUW - ES
 9. Water quality
MTSCW - EC
 9. Water quality
MSCW - EC
 9. Water quality
MOUW - ES
 10. Disease
MDAUW - EC
 10. Disease
MTSUW - ES
 10. Disease
MSUW - ES
 10. Disease
MOUW - ES
 11. Low population numbers/small populations
MDAPW - CC
 11. Low population numbers/small populations
MTSCW - HC
 11. Low population numbers/small populations
MSCL - HC
 11. Low population numbers/small populations
MOPW - CC

a Site: MDA = Maintenance Detachment Aldergrove; MTS = Mountain Slough; MS = Maria Slough; MO = Morris.

b b Relative Impact: P = Predominant; C = Contributing; U = Unknown; N = None.

c Spatial/Temporal Nature: W = Widespread; L = Localized; C = Chronic; E = Episodic; H = Historical.

d Certainty: C = confirmed based on empirical data; P = Probable; S = Speculative.

e Exotic Predators: Bf = Bullfrog; Gf = Green Frog.

f Exotic, Invasive Vegetation: reed canary grass

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Appendix 3. Maps of survival habitat for Oregon Spotted Frog in B.C.

Figure A1. Area of survival habitat (yellow shadow) for Oregon Spotted Frog around Maria Slough, B.C.

Figure A1 illustrates the area of survival habitat for the Oregon Spotted Frog at Maria Slough, B.C.

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Figure A2. Area of survival habitat (yellow shadow) for Oregon Spotted Frog around the wetland at Morris Valley, B.C.

Figure A2 illustrates the area of survival habitat for the Oregon Spotted Frog at Morris Valley, B.C.

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Figure A3. Area of survival habitat (yellow shadow) for Oregon Spotted Frog around Mountain Slough, B.C.

Figure A3 illustrates the area of survival habitat for the Oregon Spotted Frog at Mountain Slough, B.C.

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Figure A4. Area of survival habitat (yellow shadow) for Oregon Spotted Frog around the wetland at Maintenance Detachment Aldergrove, B.C.

Figure A4 illustrates the area of survival habitat for the Oregon Spotted Frog at Maintenance Detachment Aldergrove, B.C.

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