CLIMATE CHANGE, WILDLIFE AND ENDANGERED SPECIES Jan A. Randall, Professor Emeritus of Biology, San Francisco State University There seems to be almost total agreement among scientists that temperatures on earth are increasing to disrupt the planet’s climate system and cause shifts in regional patterns of temperature and precipitation (Hume 2005). Changes in climate threaten to decrease biodiversity, the sum of species and their genetic diversity, by altering environmental conditions so quickly that species cannot readily adapt (McLaughlin et al. 2002). Because each species plays an important role in the life web of its biotic community there should be increased concern about the responses of species to changes exacerbated by climate variation. Species already under stress from habitat loss and fragmentation, introduction of exotic species and pollution are especially vulnerable to the detrimental influences of global warming (Hannah et al. 2005). Because species often respond to climate change individually rather than as communities, the Endangered Species Act (ESA) is even more important now than in the past. There must be increased efforts under provisions of the ESA to identify and protect species vulnerable to the detrimental influences of climate change. The following examples illustrate the broad and varied scope of how climate change may directly or indirectly affect species’ survival and reproduction. TIMING: ADVANCEMENT OF SPRING EVENTS AND SHIFTS IN LIFE CYCLES The advancement of spring events has been documented on all but one continent and in all major oceans (Parmesan 2006). This change in timing is important because many plants and animals use a combination of day length and temperature as cues to initiate life cycle changes associated with reproduction. For example, advances in spring temperatures affect when buds burst and plants bloom, insect emerge from dormancy and animals mate. Plant-animal interactions such as pollination and seed dispersal depend on synchrony between species, and species depend on the appearance of specific foods at critical times. Global warming disrupts the timing by the advance of warm temperatures so that life cycles of organisms become asynchronous. An animal therefore may not have enough food to feed its young because life cycles no longer coincide (Visser and Both 2005). Already in the Antarctic nine species of birds are, on average, arriving nine days later to nest and laying their eggs two days later. Bird migrations. Bird migrations to northern latitudes are carefully timed to coincide with food supplies necessary for successful reproduction. Thus bird migration appears especially sensitive to warming temperatures. There is a great deal of variation in responses of birds to the advance of spring temperatures, and it is often unclear how flexible birds are to the advance of spring and which species may adapt while others may not (Parmesan 2006). If birds migrate north from the wintering grounds on the usual schedule because conditions there have not changed they may arrive at their breeding grounds past the peak of food production. These conditions may severely restrict reproductive success so populations of migratory birds in the US should be carefully monitored to determine whether the birds time their arrival with food supply as global temperatures continue to increase. SHIFTS IN RANGES AND LOCAL ABUNDANCE Latitudinal Shifts: Birds, Butterflies and Foxes. Northward expansion of bird species in North America and Europe has been widely observed over the past 50 years (McCarty 2001). Nine of 27 bird species examined in North America exhibited a significant northward shift in the northern extent of their distributions over a 26-year period. They included Inca doves, summer tanagers, blue-winged warblers, golden warblers, Kentucky warblers, hooded warblers and blue-grey gnatcatchers (Hitch and Leberg, in press). A similar trend is well documented in Great Britain (Thomas and Lennon 1999). Over the past 30–100 years, 34 of 52 species of European butterflies in the northern boundaries of their geographic ranges showed northward shifts, one species shifted southward, and there was no change in the remaining 17 species (Parmesan et al. 1999). What do these shifts in range mean for endangered species? Although many species seem able to expand their ranges northward without detrimental effects these expansions should be closely watched for limitations to the expanding species and for competition with local species. For instance, in the past 70 years the red fox (Vulpes vulpes) has expanded its range northward while the arctic fox’s (Alopex lagopus) range has contracted toward the Arctic Ocean. Because the red fox is less-well adapted to cold conditions than the Arctic fox its expansion seems related to warming trends, and retreat of the Arctic fox seems caused by the competitively superior red fox (Hersteinsson and Macdonald 1992). Altitudinal Shifts: Retreating Up the Mountain. In mountains, climates change more rapidly with elevation (about 1° C per 160 m) than with latitude so rapid changes in montane communities are expected as global warming increases (MacCarty 2001). Already, altitudinal changes in species’ distributions are becoming well documented as species shift their ranges upward seeking cooler and avoiding warmer conditions (Pounds et al. 2005). For instance, the Edith’s Checkerspot butterfly has shifted it range upward by 100 m in the Sierra Nevada mountains of California (Parmesan 1996). There have been local extinctions of a montane mammal, the little, non-hibernating rabbit that lives in high elevations on talus slopes of the Rocky Mountains, the pika (Ochotona princeps) (Beever et al. 2003). Seven of 25 populations (28%) of pikas reported earlier in the 20th century appear to have experienced recent extirpations. Because of their obligate association with discontinuously distributed talus habitat, pikas are especially vulnerable to warmer temperatures and could act as early sentinels of changes in other montane mammal species. Polar Bears and Penguins. Some of the strongest signals of global warming are from polar regions. Large increases in air temperature and extensive melting of ice shelves have been observed in the Antarctic, and the Arctic is warming nearly twice as fast as the rest of the world (Croxall et al. 2002). These dramatic changes in the environment are bound to change the distribution and abundance of marine organisms and ecosystems in the polar regions. Already there is evidence of decline in some populations of Adélie and Emperor penguins in the Antarctic and increased concern about the polar bear in the Arctic. Polar bear populations are facing threats previously unprecedented during recorded history in the Arctic. Recent climate change scenarios based upon modeling of climate trend data predict that the Arctic region will experience major changes in the upcoming decades (Schliebe 2007). Polar bears do not occur in large numbers and they have a very slow reproductive rate so their ability to replace themselves is very limited and population growth extremely slow. Their long life span helps to offset the low reproductive potential, but combination of the loss of sea ice making it more difficult to capture seals, the main food source, and human factors of hunting, oil spills and shipping activity are increasing the impact on polar bears. Global warming is a factor in the declines of populations of polar bears in Hudson and Baffin Bay in northern Canada. The early breakup of sea ice from warmer spring temperatures limits access of polar bears to seals, and they suffer an increased weight loss. The continuing fall in the average weight of bears in the Hudson Bay may be affecting the females’ ability to reproduce and the survival of their young (Stirling and Parkinson 2006). Climate warming may also alter pathways of pollutants entering the Arctic. The high fat diet and position as a top predator make polar bears especially susceptible to high concentrations of organic pollutants which affect the endocrine and immune systems and subsequent reproduction (Derocher et al. 2004). Where Have All the Frogs Gone? Amphibian populations seem to be declining at an unprecedented rate (Blaustein and Wake 1990). Many amphibian species are on the brink of extinction, with 427 species (7.4%) listed as Critically Endangered (the IUCN category of highest threat), compared with 179 birds (1.8%) and 184 mammals (Stuart et al. 2004). In California alone the mountain yellow-legged frog and the Yosemite toad are missing from most of their range in the Sierra Nevada. The arroyo toad of Southern California has vanished from three-fourths of its range, and range of the red-legged frog that once lived throughout Southern California is down to one remote area of Riverside County. Many factors seem to be involved in the decline of amphibians: ultraviolet radiation, pesticide use, pollution, pathogens, and habitat destruction from urbanization and agriculture. Global warming is sometimes correlated with die-offs, but no one has been able to show conclusively that global climate change is responsible for the major, sudden frog decline in amphibians (Beebee 1995, 2002). Thus causes are multiple but climate is certainly involved and has been directly linked to the sudden extinction of the golden toad (Bufo periglenes) in the Costa Rican cloud forest (Pounds and Crump 1994). The unusually warm and dry conditions also resulted in the local extinction of the harlequin frog (Atelopus varius) and drastic declines in populations of other species (Pounds et al. 2006 ). Whales and Fish: Shifting Plankton Blooms. There is strong evidence for systematic changes in plankton abundance and community structure over recent decades in many areas worldwide. There have been global shifts in phytoplankton and zooplankton communities in concert with regional oceanic climate shifts as well as range shifts and changes in time of peak biomass (Parmesan 2006). Antarctic krill, which are a key component of the diet of whales and other marine mammals, have declined in abundance during the past 25 years. This decline has been linked to reduced food availability for krill in the form of phytoplankton blooms in summer and ice algae in winter (Hays et al. 2005). Another dramatic impact of the reorganization of plankton communities is on commercial fisheries. During their larval stages, all fish consume zooplankton and some adult fish continue to be at least partly planktivorous. Synchrony between the peak in plankton abundance and the arrival of fish larvae in the plankton is thought to be crucial in determining the survival of fish. Pests and Disease: Disappearing Forests and the Pine Beetle. Climate warming can contribute to the spread of disease by increasing pathogen development and transmission rates, relaxing over-wintering restrictions on pathogen life cycles and modifying host susceptibility to infections (Harvell et al. 1999). A pathogen that has broadened its range because of climate warming is in the Rocky Mountains of the United State. The mountain pine beetle (Dendroctonus ponderosae) is helping to destroy vast tracks of forest land by spread of the fungus they transmit (pine blister rust) that kills the trees. The beetle has responded to warmer temperatures by altering its life cycle so that now it takes one year for a generation instead of two allowing an increase in the population abundance and attack on more trees (Parmesan 2006). PRECIPITATION PATTERNS Global climate change causes weather patterns to fluctuate locally so that some areas become drier and others wetter. In either case plant types may change to cause significant changes in the associated animals leading to local extinctions. Changes in precipitation patterns in the arid regions of the southwestern United States have resulted in local extinctions caused by a shift from arid grassland to desert shrub (Brown et al. 1997). Formerly abundant species of two seed eating rodents and two species of harvester ant declined and disappeared in southeastern Arizona. One species, the banner-tailed kangaroo rat Dipodomys spectabilis, is a keystone species and its disappearance affected abundance of several other species including lizards, burrowing owls and rattlesnakes. Several species of kangaroo rat in western United State are already threatened or endangered (six in California) making these species vulnerable to extinction if there is a shift in habitat vegetation in their limited ranges. TURTLES AND TEMPERATURE DEPENDENT SEX DETERMINATION Populations with temperature dependent sex determination may be unable to evolve rapidly enough to adjust to even minor changes in temperature. The sex of developing turtle embryos is determined by environmental temperature. Painted turtle (Chrysemys picta) eggs raised under warmer conditions produce female offspring, whereas males are produced under cooler conditions. Painted turtles could suffer local extinctions in the near future, solely as a result of the skewed sex ratio and resulting demographic problems created by a warming climate. A sustained increase in temperature (4oC) could result in the extinction of this species because no males would be produced (Janzen 1994). In another example, the endangered logger-head sea turtle (Caretta caretta) had 87-99% female hatchlings in a region where sand temperatures were high (Mrosovsky and Provancha 1992). CORAL BLEACHING The biodiversity of coral reefs is extraordinary and any changes in reef-building communities are likely to have huge impacts on marine biodiversity (Hoegh-Guildberg 2005). Coral live in a symbiotic relationship with algae that provide food for the coral through photosynthesis. Coral bleaching occurs when the algae are expelled from the coral because of stress from factors such as increased salinity, disease, or increased sea surface temperatures. Because reef-building coral that lose their symbionts may experience mortality rates of up to 90%, long-term warming trends, coupled with extreme El Nino events, have raised concerns that global warming will trigger more frequent and widespread episodes of bleaching to cause irreparable damage to diversity in the reefs (Harvell et al. 2002). Because some coral are so sensitive that 100% bleaching is reached with temperature increases of slightly less than 1°C, many reefs may be reaching their thermal tolerance limits now (Hoegh-Guldberg 2005). WILD FIRES Increased wildlife activity is strongly associated with increased spring and summer temperatures and an earlier spring snowmelt. In the United States higher large-wildfire frequency, longer wildfire durations, and longer wildfire seasons began to occur in Northern Rockies forests in the mid-1980s with the greatest increases in mid-elevation, areas where land-use histories have had relatively little effect on fire risks (Westerling et al. 2006). These intense fires can cause severe damage to the habitat and potentially help drive species with limited ranges toward extinction. CONCLUSION The effects of climate change are varied and pervasive with the detrimental consequences for biodiversity already apparent. Without quick and decisive action many of the species that we know and love may eventually reach a state of no return. The Endangered Species Act should be strengthen rather than weakened and sufficient funding provided to implement provisions of the act and to compensate land owners. Under the ESA there should be increased listing of new endangered species based on the best scientific evidence available before populations decline to critical levels, increased habitat protection including all habitat within critical habitat areas, a halt to projects that have been determined to threaten species with extinction, and implementation of recovery plans. To maintain continuity in protection (state boundaries are irrelevant to wildlife) Federal oversight of endangered species listing and protection should continue in cooperation with state governments. Through these efforts we can mitigate the influences of climate change on biodiversity and meet our responsibility to protect endangered species and the special places they call home. Prepared by Jan Randall for the Endangered Species Coalition www.stopextinction.org Endangered Species Day website www.stopextinction.org/EndangeredSpeciesDay For more information, contact Sarah Matsumoto at firstname.lastname@example.org REFERENCES Beebee, T. J. C. 1995. Amphibian breeding and climate. Nature 374: 219–220. Beebee, T. J. C. 2002. Amphibian phenology and climate change. Conservation Biology 16: 1454. Beever, E. A., Brussard, P. F. & Berger, J. 2003. Patterns of apparent extirpation among isolated populations of pikas (Ochotona princeps) in the Great Basin. Journal of Mammalogy 84:37-54. Blaustein, A. R. & Wake, D. B. 1990. Declining amphibian populations: a global phenomenon? Trends in Ecology and Evolution 5:203–204. Brown, J. H., Valone, T. J. &. Curtin, C. G. 1997. 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