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 3 R. columbianus/ li@oralis R. columbianus/ vancouverensis 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.
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 we don t know
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 william.gerth@oregonstate.edu
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! william.gerth@oregonstate.edu
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