SFS Annual Meeting

5/21/2019  |   09:00 - 09:15   |  250 DE

GROWTH AND SURVIVAL JOINTLY PREDICT THE UPPER THERMAL LIMITS OF THE STONEFLY PTERONARCYS CALIFORNICA Species distribution models (SDMs) imply that temperature is a dominant factor influencing the distribution of freshwater macroinvertebrates. However, a strong SDM-derived relationship between temperature and probability of occurrence does not guarantee a causal association. If temperature predictors used in SDMs have a causal basis, we should be able to experimentally validate SDMs by assessing how fitness measures vary with temperature. We hypothesized that growth and survival would jointly predict upper temperature limits (UTLs) derived from SDMs. To test this hypothesis, we reared nymphs of Pteronarcys californica under 7 temperatures (13-24°C) and measured growth and survivorship in each treatment over 70 days. The product of growth and survivorship (fitness) in the lab experiments dropped to zero at 24°C. This value is higher than the UTL of 21°C estimated from two field datasets. However, the difference between the lab- and field-inferred UTLs is consistent with the generalization that realized niches (field) are more narrow than fundamental niches (lab). We conclude that temperature likely influences the distribution of P.californica through its effect on individual fitness. We are currently conducting similar experiments on several other species to more comprehensively test our hypothesis.

Donald Benkendorf (Primary Presenter/Author), Utah State University, donald.benkendorf@aggiemail.usu.edu;


Charles Hawkins (Co-Presenter/Co-Author), Utah State University, chuck.hawkins@usu.edu;


Presentation:
This presentation has not yet been uploaded.

5/21/2019  |   09:15 - 09:30   |  250 DE

RESOURCES AND HABITAT INTERACT TO AFFECT MACROINVERTEBRATE COMMUNITIES ACROSS AGRICULTURAL GRADIENTS IN TWO BIOMES. The intensity of agricultural land use within catchments simplifies macroinvertebrate community structure by homogenizing substrate, degrading water quality, and changing resource availability. How water quality and dispersal barriers from habitat fragmentation and loss of riparian area influence macroinvertebrate communities under varying agricultural land use (e.g., row crop vs. pasture) is less understood. Therefore, we quantified the relative effect of row-crop and pasture on macroinvertebrates using standardized artificial substrate samplers, in 10 Arkansas catchments across a pasture gradient (0-75%) and 10 Michigan catchments across a row-crop gradient (45-88%). We predicted row-crop would result in greater total density, fewer macroinvertebrate taxa, and lower functional diversity relative to pasture due to altered resources. Macroinvertebrate richness increased by 52% across the pasture gradient but decreased by 68% across the row-crop gradient. Taxa composition differed more across pasture than row-crop, likely due to greater variation in percent land cover. Functional groups shifted from filterers to predators with increasing row-crop, but not in the pasture gradient. Overall densities did not change because as predator density increased filterers decreased. Water quality and dispersal limitations may act as stronger filters in pasture influenced streams than row-crop influenced streams.

Matt Trentman (Co-Presenter/Co-Author), Flathead Lake Biological Station, University of Montana, matt.trentman@flbs.umt.edu;


Jennifer L. Tank (Co-Presenter/Co-Author), University of Notre Dame, tank.1@nd.edu;


Sally Entrekin (Co-Presenter/Co-Author), Virginia Tech, sallye@vt.edu;


Danielle Braund (Primary Presenter/Author), University of Central Arkansas, dbraund1@cub.uca.edu;


Presentation:
This presentation has not yet been uploaded.

5/21/2019  |   09:30 - 09:45   |  250 DE

POPULATION LEVEL VARIATION IN PESTICIDE TOLERANCE IN HEPTAGENIIDAE Anthropogenic activities can have significant ecological and evolutionary consequences on populations in natural systems. In the Midwest, neonicotinoid insecticides are widespread across the agricultural landscape and frequently detected in stream systems. The effects on heptageniidae mayflies is a major concern because they are highly sensitive to neonicotinoids and have some of the lowest reported EC50 values of any organism. Here we conducted EC50 tests on populations of heptageniids across a gradient of agricultural landcover to assess patterns of tolerance to the neonicotinoids clothianidin and thiamethoxam. Additionally, we collected water samples to assess temporal patterns of neonicotinoid presence in stream habitats. We found variation in neonicotinoid tolerance with EC50 values from 4.9 µg/L to 32 µg/L and 19.8 µg/L to 86.5 µg/L for clothianidin and thiamethoxam, respectively. However, agricultural landcover was not associated with neonicotinoid tolerance. Moreover, water samples demonstrated that the amount of agricultural landcover was not a strong predictor of neonicotinoids presence. Our data suggest that populations of heptageniidae mayflies can vary substantially in neonicotinoid tolerance. As mayflies are widely used in rapid bioassessment protocols, an important next step is determining whether these patterns are consistent with evolved tolerance.

Jason Hoverman (Co-Presenter/Co-Author), Purdue University, jhoverm@purdue.edu;


D. Riley Rackliffe (Primary Presenter/Author), Purdue University, dracklif@purdue.edu;


Presentation:
This presentation has not yet been uploaded.

5/21/2019  |   09:45 - 10:00   |  250 DE

HOW DO BEAVERS INTERACT WITH FLOW HOMOGENIZATION TO CHANGE AQUATIC INVERTEBRATE COMMUNITIES? In free-flowing, temperate rivers, beavers and their structures can enhance river ecosystems by increasing the diversity and abundance of fish, aquatic invertebrates, and riparian plants. However, natural desert rivers have stochastic flood and drought events which can limit beaver structures and populations. Additionally, the majority of rivers worldwide have homogenized flows through the reduction of flood and drought magnitude and frequency for flood control, hydropower, and other human needs. Utilizing a long-term dataset (2006 to 2018) from the Bill Williams River, Arizona, one of the most flow-homogenized rivers in the Western U.S., our research quantifies how beaver activity and flow homogenization interact to change the structure and function of aquatic invertebrate communities. We sampled aquatic invertebrates and collected physio-chemical data from one free-flowing reference site above Alamo Dam and two impacted sites below Alamo Dam. Our findings show that when combined with flow homogenization, beaver activity can become “too much of a good thing” by converting river corridors to a monoculture of pool habitats which reduces the diversity of species traits that could ultimately lead to more degraded ecosystems than flow homogenization alone.

David DuBose (Primary Presenter/Author), Oregon State University, dubosed@oregonstate.edu;


Laura McMullen (Co-Presenter/Co-Author), Oregon State University, laurabethmcm@gmail.com;


Jonathan Tonkin (Co-Presenter/Co-Author), University of Canterbury, jonathan.tonkin@canterbury.ac.nz;


Dave Lytle (Co-Presenter/Co-Author), Oregon State University, lytleda@oregonstate.edu;


Presentation:
This presentation has not yet been uploaded.

5/21/2019  |   10:00 - 10:15   |  250 DE

A COMPARISON OF MACROINVERTEBRATE DRIFT IN A 4TH ORDER REACH OF THE AU SABLE RIVER, MI. The Au Sable River (MI) is a 4th order blue ribbon trout stream that has experienced an array of changes during the past 50 years, including diversion of sewage effluent and removal of a low-head dam. We evaluated invertebrate drift for 24 hours at 3 sites on 3 dates to replicate drift studies conducted in 1969 and 1996. Drift typically peaked between midnight and 5 am and was dominated by mayflies. Drift was lowest during day light hours. Total drift abundance at a single sample location was reported to be 8,489 organisms day?¹ net?¹ before the sewage diversion (1969) and 4,535 organisms day?¹ net?¹ after effluent diversion (1996). In comparison, we estimated drift in 2018 to be 11,418 organisms day?¹ net?¹ at the same site. Although effluent diversion significantly reduced nutrient loading, 2018 invertebrate drift exceeded previous drift abundance suggesting that nutrient reductions have not diminished invertebrate drift.

Barney Boyer (Primary Presenter/Author), Grand Valley State University, boyerb@mail.gvsu.edu;


Presentation:
This presentation has not yet been uploaded.