Ramellogammarus similimanus Portland Metro’s own freshwater crustacean species: What we know and don’t know Bill Gerth Oregon State University Department of Fisheries & Wildlife Amphipods • Small, shrimp-­‐like crustaceans • Also called scuds or side-­‐swimmers • Most species are marine, but reasonable number in freshwater In freshwater • found in a variety of habitats • can be very abundant where they are present •  important in aquaJc food webs –  OLen found in fish diet –  Feeding varies, generally consume/shred decaying plant material or feed opportunisJcally •  interesJng reproducJve behavior –  Mate-­‐guarding –  Female carries the eggs unJl they hatch How to recognize amphipods • Small, shrimp-­‐like crustaceans • Laterally compressed, segmented bodies • 7 pairs of legs (14 legged) • Abdomen has extra appendages • 2 pairs of antennae Abdomen with extra appendages 2 pairs of antennae 7 pairs of legs— first 2 pairs modified What types of amphipods are common in the Portland Metro area? 3 amphipod genera common in habitats that are usually sampled: Crangonyx, Hyalella, and Ramellogammarus •  Crangonyx and Hyalella species widespread in North America •  Ramellogammarus species found in the Pacific Northwest and nowhere else Crangonyx Hyalella Ramellogammarus Not much known about Ramellogammarus species Why? •  Only in the Pacific Northwest •  UnJl recently, the genus Ramellogammarus not even included in major keys for North American freshwater invertebrates–so specimens misidenJfied as Gammarus. (updated keys: Pennak, 2001; Thorp & Covich, 2009) •  Even when the genus is ID’d correctly, Ramellogammarus species rarely disJnguished in biomonitoring samples •  Because of this, we know pre\y li\le about the ecology & distribuJon of these species, which contribute to our regional biodiversity. What do we know about Ramellogammarus species? Most of published info about the genus Ramellogammarus and its species in Bousfield & Morino, 1992. Key to disJnguish the 9 known species, but limited informaJon on distribuJons Based on specimens available at the Jme, •  Most species thought to occur in streams very close to the Pacific Coast •  Two species, R. similimanus & R. oregonensis, were known to occur in Portland Our Ramellogammarus studies •  Began in 2005, when we started noJcing Ramellogammarus specimens collected from unexpected locaJons. •  Since then, we have worked to learn more about Ramellogammarus species and their distribuJons. •  In this effort, we amassed the world’s largest collecJon of Ramellogammarus specimens. RelaRonships among Ramellogammarus species RelaJonships based on DNA analyses R. oregonensis R. species 1 R. californicus 1 R. species 2 R. ramellus 2 R. columbianus/ li@oralis R. columbianus/ vancouverensis 3 R. similimanus •  Our recent DNA analyses suggest 3 species groups •  The 2 Portland-­‐area species from divergent lineages CollecRon locaRons for R. oregonensis •  Even in 1992, R. oregonensis was known to be somewhat widespread-­‐-­‐Found in Portland area, but not confined there •  now known distribuJon is larger than previously known—found in many types of habitats Bousfield & Morino 1992 Our collecJons 2005—2013 CollecRon locaRons for R. similimanus •  Bousfield and Morino’s paper: R. similimanus only known from specimens collected in 1958 at a single locaRon—Crystal Springs in SE Portland—co-­‐occurred with R. oregonensis •  This species was largely ignored aLer it was discovered •  ALer 50 years of obscurity, we found this species again in springs on Reed College campus in 2008. •  R. similimanus & R. oregonensis co-­‐occurred in springs heads, but only R. oregonensis in creek just downstream. CollecRon locaRons for R. similimanus •  Since then, expanded the known distribuJon by targeJng collecJons in/near springs in Portland east of the Willame\e and in southern Vancouver, WA •  and by examining archived biomonitoring samples from streams in Portland Metro parks •  Only found in springs east of the Willame\e– again R. similimanus & R. oregonensis both in springs heads, but only R. oregonensis in habitats downstream. •  Found in streams without R. oregonensis west of the Willame\e Currently R. similimanus is only known from the Portland Metro area •  If they really do only occur here CELEBRATE!
! Few if any other metro areas have species they can call their own •  However, only occurring in a metro area can also lead to a risk of exJncJon Double-­‐whammy of exRncRon risks •  R. similimanus appears to be a narrow-­‐range endemic species = species that only occurs in a limited geographic area or habitat •  these types of species at greater risk of exJncJon than species with wider geographic distribuJons Ø  many or all of the individuals in a the species could be affected by environmental disturbance in a small geographic area •  Because urbanizaJon generally degrades aquaJc habitat and water quality, narrow-­‐range endemic aquaJc species that only occur in urban or urbanizing areas have an even higher exJncJon risk. What we don’t know •  We sJll need more informaJon to be able to implement appropriate conservaJon measures. •  Do any R. similimanus populaJons exist outside of the Portland Metro area? •  How sensiJve is R. similimanus to watershed urban development? What’s next in our lab •  ConJnue to collect in areas around R. similimanus’ currently known distribuJon to determine if they can be found outside Portland Metro. •  Build on the DNA informaJon we have to developed in our previous research Ø  Develop tools to detect R. similimanus DNA in water samples—eliminate the need to collect specimens •  Use informaJon on where R. similimanus occurs to model the environmental tolerances of this species Want to help? Here’s how you can… •  Provide biomonitoring data Ø  Places where Ramellogammarus specimens were found previously are ideal locaJons to resample and determine species •  Provide archived samples/specimens Ø  If you have archived specimens, I would be happy to ID the species •  Look for Ramellogammarus specimens in aquaJc habitats near your home or work Ø  Collect gently: Disrupt habitat as li\le as possible Collect the largest specimens available—can’t ID species if < 3mm long Don’t collect more than 20 specimens from any one locaJon Take Home Messages •  Ramellogammarus species are an important part of our regional biodiversity •  R. similimanus appears to be a narrow-­‐range endemic species confined to the Portland Metro area Ø  The species could easily disappear with li\le noJce unless we are careful Ø  More informaJon is needed to make appropriate conservaJon plans •  If you know want to join Team Ramellogammarus, please get in touch [email protected] Thanks to invaluable supporters •  My collaborator, Alan Herlihy. •  Everyone in the Lytle lab (OSU-­‐Zoology): especially Emily Harnield-­‐Kirk Thanks to invaluable supporters •  Many, many folks who collected specimens in the field with me or sent me specimens. Thanks to invaluable supporters •  Mentors who helped make this work possible Judy Li Christopher Rogers •  Funding was provided by the Oregon State University General Research Fund Happy Holidays and Go Team Ramellogammarus! [email protected] Q: Are other data available from Portland area aquaRc habitats? A: Yes—a 2001 Metro study of macroinvertebrates in streams Ø  Samples processed in our lab, but before keys to ID Ramellogammarus widely available Ø  Specimens in archived samples re-­‐examined 54 stream sampled at parks throughout the Metro area What’s next in our lab •  ConJnue to collect in areas around R. similimanus’ currently known distribuJon to determine how widely they truly occur. •  Build on the DNA informaJon we have to developed in our previous research Ø  Develop tools to detect R. similimanus DNA in water samples—eliminate the need to collect specimens •  Use informaJon on where R. similimanus occurs to model the environmental tolerances of this species