**4. Discussion**

68 Biodiversity Loss in a Changing Planet

Fig. 7. Biodiversity of seaweeds is listed for the last two climate regimes (1989-2000 and 2001-2010). All abundance ratings are included. Considerable effort took place in these three regions. WCVI = west coast Vancouver Island, JSTR = Johnstone Strait and SoG = Strait of Georgia. Numbers of dives are listed in parentheses for regime periods. Black bars = flowering plants, white = green algae, dark gray = brown algae, light gray = red algae (see

Table 2 for species with abundance rating of 2 or more).

Overall, biodiversity was quite stable in the two most heavily investigated regions, west coast Vancouver Island and Strait of Georgia, for the study period of 1967-2010. The long duration of this biodiversity monitoring has involved an expanding network of experts and the discovery and description of new species so that the biodiversity list has continually expanded. For that reason, most of the results presented necessarily dealt with a curtailed species list of 328 species identified during the first climate regime period. This biodiversity stability has occurred through successive climate regimes and despite the continuous reduction in seawater pH, through global warming and through the continued state of stock depletion of fished groundfish and other fish species during that period. It is beyond the

localized fluctuations between stable states.

possible influences.

British Columbia, Canada Through Climate Regimes, Overfishing and Ocean Acidification 71

biodiversity differences from adjacent areas of different habitat characteristics. As well, that paper discusses the effects of sea urchins in creating "urchin barrens" where seaweeds are essentially absent in a confined area for some period of years. The effect of sea otters (*Enhydra lutris*) on reducing sea urchin densities and enhancing abundance and diversity of seaweeds is well demonstrated (Estes & Duggins, 1995) and is considered to relate to ecological stable states in terms of community persistence, resilience and stability. Such studies are typically conscribed to encompass specific study sites, whereas the present data compilation pools data from many sites for many years. It is likely that persistence of communities fluctuates with episodes of herbivore densities, as with urchin barrens, and that the present large-scale compilation masks shorter-term, more

The assessment of the 1977, 1989 and 2001 climate regime shifts may be confounded by the effects of overfishing and changing seawater acidity, but there is no basis for integrating those different effects. Nonetheless, this data presentation demonstrates that long-term records of pH do exist and that acidification trends can be related to trends in taxonomic diversity. Many fishing effects took place before this entire survey period, however (Levy et al. 1996). There has been no decline in biodiversity correlated to the trend of ocean acidification, with the possible exception of the disappearance of bull kelp (*Nereocystis luetkeana*) from mid-latitudes of the Strait of Georgia, especially the Sunshine Coast, where decline of bull kelp occurred during the time of dropping pH (Lamb et al., 2011). It should be noted, however, that the disappearance of bull kelp in middle latitudes of the Strait of Georgia has coincided with the establishment of the highest densities of human population in that part of the Strait of Georgia and where currents are generally least powerful (Lamb et al., 2011). Finally, the Strait of Georgia has warmed by one degree Centigrade over this same period from 1970 (Beamish et al., 2010). The greatest challenge in ecosystem-based management is to determine causal relationships where multiple correlations appear to be evident. Climate regime shifts were selected as the parameter on which to base comparisons since regimes have supposedly reversed two times (possibly three) during this overall period, but the biodiversity of this region has emerged as quite stable despite all of these

There is only a very limited signal of climate regime shifts, particularly as reflected in changes in seaweed biodiversity after the regime shift of the year 2000. Seaweed identification was not well established by the present team during the first two regimes encompassed in the period from 1967-2010, so there is no long-term baseline for assessing seaweed biodiversity through time. Diversity of various seaweeds, however, showed signs of increasing at more northern latitudes and decreasing at the more southern latitudes in Washington state (outer coast Washington and Puget Sound), but the sampling effort may well have led to spurious appearance of lower seaweed occurrence in these southern areas. The most conservative data for the original list of 328 species shows stability. Note that few seaweeds occur in that list, so the apparent increase in seaweed diversity in recent years may relate to increased expertise in field identification. It can be discerned from Figures 4 and 5 that there was not only limited focus on seaweed identification in the early years, but that it took some time for groups of more plastic morphology like sponges and bryozoans to be registered in all areas. The greatest effort took place in the Strait of Georgia, which shows the greatest stability of biodiversity, probably to a considerable degree because of the level of effort. This was also a region

scope of this chapter to review the full literature on fisheries sustainability in the Strait of Georgia, but the reader may consult the review by Levy et al. (1996) to see a summary of historic declines in shellfish and finfish stocks in that region. There appear to have been no concomitant declines in overall biodiversity as one or another species has fluctuated in abundance. Consistent differences, however, persisted between adjacent regions, compared to the Strait of Georgia.

The region designations presented here are not based on any existing literature or governmental statistical areas for fisheries surveys. In fact, it may seem exceptional that smaller areas that seem to be inland seas are lumped together with outer coast areas such as the west coast of Vancouver Island (here including Queen Charlotte Strait inside the north end of Vancouver Island) and the extreme eastern end of the Strait of Juan de Fuca within the region of the outer coast of Washington. In the data compilation of Lamb et al. (2011) the occurrence of the exposed coast indicator species *Pyllospadix scouleri* and *Strongylocentrotus purpuratus* (Lamb & Hanby, 2005) on the southern coast of San Juan and Lopez Islands and the west coast of Whidbey Island was a rationale for designating these areas part of the fully wave-exposed outer coast rather than the protected inland seas of either Puget Sound or the Strait of Georgia, where all remaining portions of the San Juan Islands were included. The different, yet stable, biodiversities of the communities in these broad regions attest to the validity of the present region designations, and contrast rather markedly with some fisheries statistical areas. It might be well to conduct analyses of fisheries data in accordance with the present regional boundaries (Figure 1).

The literature is equivocal on whether a climate regime shift occurred in 1989, so results have been presented for both three and four climate regimes during the 1967-2010 period of this present study. Note that the first regime (here, 1967-1976) is actually considered to have persisted for a much longer time, from 1947-1976 (McFarlane et al., 2000). Whether the middle study period of 1977-2000 is considered to consist of just one climate regime or of two regimes (1977-1988, 1989-2000), the biodiversity appears (Figures 4, 5) to have been higher during that period than during either the first or last regimes. As well, differences between the second and third of the four regimes occurred (Figure 5), so that 1989 does appear to mark a climate regime shift, as proposed by McFarlane et al. (2000), from the standpoint of biodiversity, supporting the contention of Hare & Mantua (2000) that biodiversity accurately defines regime shifts. This is despite the evidence for increased observer expertise and improved capacity generally for taxonomic identifications based on field observation. Thus, there does appear to have been a slight overall reduction in biodiversity in recent years, in terms of the basic list of 328 species (mostly animals), in contrast to possible increases in seaweed biodiversity (based on the full species list).

The collation of species for one site at Whytecliff in four different climate regimes enabled a view of trends without concern over effects of habitat differences between sites within a region. The detailed data compilations for different areas within the Strait of Georgia region (Lamb et al., 2011) revealed that broad differences in biodiversity exist between different areas, apparently related to presence of high-energy tidal passes in areas like the southern Gulf Islands (Active Pass, Gabriola Pass, Porlier Pass) and Burrard Inlet (First Narrows, Second Narrows), where seaweed biodiversity is elevated in comparison to areas in middle latitudes of the Strait of Georgia. That study also showed considerable stability through time for those smaller areas in terms of their

scope of this chapter to review the full literature on fisheries sustainability in the Strait of Georgia, but the reader may consult the review by Levy et al. (1996) to see a summary of historic declines in shellfish and finfish stocks in that region. There appear to have been no concomitant declines in overall biodiversity as one or another species has fluctuated in abundance. Consistent differences, however, persisted between adjacent regions, compared

The region designations presented here are not based on any existing literature or governmental statistical areas for fisheries surveys. In fact, it may seem exceptional that smaller areas that seem to be inland seas are lumped together with outer coast areas such as the west coast of Vancouver Island (here including Queen Charlotte Strait inside the north end of Vancouver Island) and the extreme eastern end of the Strait of Juan de Fuca within the region of the outer coast of Washington. In the data compilation of Lamb et al. (2011) the occurrence of the exposed coast indicator species *Pyllospadix scouleri* and *Strongylocentrotus purpuratus* (Lamb & Hanby, 2005) on the southern coast of San Juan and Lopez Islands and the west coast of Whidbey Island was a rationale for designating these areas part of the fully wave-exposed outer coast rather than the protected inland seas of either Puget Sound or the Strait of Georgia, where all remaining portions of the San Juan Islands were included. The different, yet stable, biodiversities of the communities in these broad regions attest to the validity of the present region designations, and contrast rather markedly with some fisheries statistical areas. It might be well to conduct analyses of fisheries data in accordance with the present regional

The literature is equivocal on whether a climate regime shift occurred in 1989, so results have been presented for both three and four climate regimes during the 1967-2010 period of this present study. Note that the first regime (here, 1967-1976) is actually considered to have persisted for a much longer time, from 1947-1976 (McFarlane et al., 2000). Whether the middle study period of 1977-2000 is considered to consist of just one climate regime or of two regimes (1977-1988, 1989-2000), the biodiversity appears (Figures 4, 5) to have been higher during that period than during either the first or last regimes. As well, differences between the second and third of the four regimes occurred (Figure 5), so that 1989 does appear to mark a climate regime shift, as proposed by McFarlane et al. (2000), from the standpoint of biodiversity, supporting the contention of Hare & Mantua (2000) that biodiversity accurately defines regime shifts. This is despite the evidence for increased observer expertise and improved capacity generally for taxonomic identifications based on field observation. Thus, there does appear to have been a slight overall reduction in biodiversity in recent years, in terms of the basic list of 328 species (mostly animals), in

contrast to possible increases in seaweed biodiversity (based on the full species list).

The collation of species for one site at Whytecliff in four different climate regimes enabled a view of trends without concern over effects of habitat differences between sites within a region. The detailed data compilations for different areas within the Strait of Georgia region (Lamb et al., 2011) revealed that broad differences in biodiversity exist between different areas, apparently related to presence of high-energy tidal passes in areas like the southern Gulf Islands (Active Pass, Gabriola Pass, Porlier Pass) and Burrard Inlet (First Narrows, Second Narrows), where seaweed biodiversity is elevated in comparison to areas in middle latitudes of the Strait of Georgia. That study also showed considerable stability through time for those smaller areas in terms of their

to the Strait of Georgia.

boundaries (Figure 1).

biodiversity differences from adjacent areas of different habitat characteristics. As well, that paper discusses the effects of sea urchins in creating "urchin barrens" where seaweeds are essentially absent in a confined area for some period of years. The effect of sea otters (*Enhydra lutris*) on reducing sea urchin densities and enhancing abundance and diversity of seaweeds is well demonstrated (Estes & Duggins, 1995) and is considered to relate to ecological stable states in terms of community persistence, resilience and stability. Such studies are typically conscribed to encompass specific study sites, whereas the present data compilation pools data from many sites for many years. It is likely that persistence of communities fluctuates with episodes of herbivore densities, as with urchin barrens, and that the present large-scale compilation masks shorter-term, more localized fluctuations between stable states.

The assessment of the 1977, 1989 and 2001 climate regime shifts may be confounded by the effects of overfishing and changing seawater acidity, but there is no basis for integrating those different effects. Nonetheless, this data presentation demonstrates that long-term records of pH do exist and that acidification trends can be related to trends in taxonomic diversity. Many fishing effects took place before this entire survey period, however (Levy et al. 1996). There has been no decline in biodiversity correlated to the trend of ocean acidification, with the possible exception of the disappearance of bull kelp (*Nereocystis luetkeana*) from mid-latitudes of the Strait of Georgia, especially the Sunshine Coast, where decline of bull kelp occurred during the time of dropping pH (Lamb et al., 2011). It should be noted, however, that the disappearance of bull kelp in middle latitudes of the Strait of Georgia has coincided with the establishment of the highest densities of human population in that part of the Strait of Georgia and where currents are generally least powerful (Lamb et al., 2011). Finally, the Strait of Georgia has warmed by one degree Centigrade over this same period from 1970 (Beamish et al., 2010). The greatest challenge in ecosystem-based management is to determine causal relationships where multiple correlations appear to be evident. Climate regime shifts were selected as the parameter on which to base comparisons since regimes have supposedly reversed two times (possibly three) during this overall period, but the biodiversity of this region has emerged as quite stable despite all of these possible influences.

There is only a very limited signal of climate regime shifts, particularly as reflected in changes in seaweed biodiversity after the regime shift of the year 2000. Seaweed identification was not well established by the present team during the first two regimes encompassed in the period from 1967-2010, so there is no long-term baseline for assessing seaweed biodiversity through time. Diversity of various seaweeds, however, showed signs of increasing at more northern latitudes and decreasing at the more southern latitudes in Washington state (outer coast Washington and Puget Sound), but the sampling effort may well have led to spurious appearance of lower seaweed occurrence in these southern areas. The most conservative data for the original list of 328 species shows stability. Note that few seaweeds occur in that list, so the apparent increase in seaweed diversity in recent years may relate to increased expertise in field identification. It can be discerned from Figures 4 and 5 that there was not only limited focus on seaweed identification in the early years, but that it took some time for groups of more plastic morphology like sponges and bryozoans to be registered in all areas. The greatest effort took place in the Strait of Georgia, which shows the greatest stability of biodiversity, probably to a considerable degree because of the level of effort. This was also a region

No. 1, pp.424-439, ISSN 1942-5120

1, pp. 75-100, ISSN 0012-9615

55017-361-8, Madeira Park BC

pp. 885-1006, ISSN 1205-7533

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Publishing, ISBN 978-1-55017-471-7, Madeira Park BC

University of California, Davis).

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**7. References** 

British Columbia, Canada Through Climate Regimes, Overfishing and Ocean Acidification 73

Perry Poon, Eugene Ruff, Paul Scott, Kelly Sendall, Bob Van Syoc, Gary Williams, Bruce Wing and Bruce Whitaker. Also, from among many dive partners, thanks are specially owed to Bernie Hanby, Steve Martell, Paul Malcolm, Conor McCracken and Alejandro Frid for assistance in the field. Kris Moulton created the map of study regions. Portions of the diving for this work were supported by donations from members of the Howe Sound Research and Conservation Group and the Vancouver Aquarium Board of Directors, as well as by a grant from the SeaDoc Society through the Wildlife Health Center (School of Veterinary Medicine,

Beamish RJ, Sweeting RM, Lange KL, Noakes DJ, Preikshot D & Neville CM. (2010) Early

Byrne RH, Mecking S, Feely RA & Liu X. (2010) Direct observations of basin-wide

Dixson DL, Munday PL & Jones GP. (2010) Ocean acidification disrupts the innate ability of

Estes JA & Duggins DO. (1995) Sea otters and kelp forests in Alaska: generality and

Frid A & Marliave J. (2010) Predatory fishes affect trophic cascades and apparent

Hare SR & Mantua NJ. (2000) Empirical evidence for North Pacific regime shifts in

Lamb A & Edgell P. (2010) *Coastal Fishes of the Pacific Northwest* (2nd edition), Harbor

Lamb A, Gibbs D & Gibbs C. (2011) *Strait of Georgia Biodiversity in Relation to Bull Kelp* 

Lamb A & Hanby BP. (2005) *Marine Life of the Pacific Northwest,* Harbor Publishing, ISBN 1-

Levy DA, Young LU & Dwernychuk LW (Eds.). (1996) *Strait of Georgia Fisheries Sustainability Review*. West Coast Reproduction, ISBN 0-9680214-0-9, Vancouver BC Marliave J & Challenger W. (2009) Monitoring and evaluating rockfish conservation areas in

Marliave JB, Conway KW, Gibbs DM, Lamb A & Gibbs C. (2009) Biodiversity and rockfish

Canada. *Marine Biology* Vol. 156, No. 11, pp. 2247-2254, ISSN 0025-3162

marine survival of coho salmon in the Strait of Georgia declines to very low levels. *Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science* Vol. 2,

acidification of the North Pacific ocean. *Geophysical Research Letters* Vol. 37, No. 2,

fish to detect predator olfactory cues. *Ecology Letters* Vol. 13, No. 1, pp.68-75, ISSN

variation in a community ecological paradigm. *Ecological Monographs,* Vol. 65, No.

competition in temperate reefs. *Biology Letters* Vol. 6, No. 4, pp. 533-536, ISSN 1744-

1977 and 1989. *Progress in Oceanography* Vol. 47, Nos. 2-4, pp. 103-145, ISSN 0097-

*Abundance*. Pacific Fisheries Resource Conservation Council, ISBN 1-897110-70-6,

British Columbia. *Canadian Journal of Fisheries and Aquatic Sciences,* Vol. 66, No. 6,

recruitment in sponge gardens and bioherms of southern British Columbia,

where there was a tendency for continuing accumulation of additional species with repeated monitoring (Figure 3).

It is important to have continuity for single surveys such as the present in order to be able to evaluate relational databases that may in the future be derived from disparate studies that do not have equivalent metadata. The PMLS database has been used to assess bull kelp abundance (Lamb et al., 2011) and it has been found that biodiversity does not change when bull kelp disappears from a location. That publication by Lamb et al. (2011) also includes a complete species list with abundance data for the greater Strait of Georgia region, and serves as an adjunct to this present publication for reference purposes.
