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University of Michigan Biological Station

The University of Michigan Biological Station (UMBS) was founded in 1909.

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Quantification of burrows between burrowing and non-burrowing species of crayfish

Aquatic
Project Abstract: 
Closely related species of crayfish construct and use a structurally diverse variety of shelters and burrows that serve as invaluable resources. Males of some species construct deep, complex burrows, which serve as resources that are beneficial in mate guarding and brood care (Richardson, 2007). Other species of crayfish create simple, shallow burrows that are utilized mainly for predator avoidance (Richardson, 2007). The differences in shelter construction and access between closely related species would guide my future research about the potential for burrows to act as both a resource and as a signal to influence female mate choice. I will be surveying crayfish population demographics for burrowing and non-burrowing crayfish species. I will be quantifying burrow structure by creating casts of burrow using polyester resin. Excavated burrows and collected crayfish will be quantified using 3D modeling software. I will analyze relationships between burrow characteristics, crayfish species, and crayfish characteristics using mixed models in R.
Investigator(s): 
Paul Moore
Cassidy Florey
Investigators: 
clflorey
Years Active: 
2018
Methods: 
I will be conducting my field work in locations throughout Northern Michigan, specifically Wilderness State Park and Cecil Bay (permits pending). Wilderness State Park and Cecil Bay have unique environmental features that are excellent habitat for species of crayfish. Cambarus diogenes will serve as a model species for primary burrowers, which construct their own burrows (Richardson, 2007). C. diogenes is present in Cecil Bay, which is characterized by Lake Michigan shoreline, wetlands, and swale complexes ideal for burrowing activity (personal communication, Paul Moore). Orconectes rusticus will serve as a model species for secondary burrowers, which adopt burrows constructed by other organisms (Richardson, 2007). O. rusticus can be found in the Carp River that flows through Wilderness State Park (personal communication, Paul Moore). In this study, I will be collecting location data on 10 identified male crayfish burrows for each species (20 burrows total). In order to quantify crayfish burrow structure, I will create casts of burrows using polyester resin (Rowden & Jones, 1995; Rudnick, Chan, & Resh, 2005). Once the structure is hardened, burrows will be excavated from the ground and transported back to UMBS for analysis. In the field, the crayfish located in the burrow will be extracted using yabby pumps before the cast is made, and sex, carapace size, chelae size, and age of crayfish will be determined. Data of burrow morphology and size will be collected using 3D modeling software (ImageJ). The total volume, depth, number of chambers, and other morphometrics will be collected from burrow. GPS location of the burrow will be recorded, as well as soil characteristics (water saturation and soil type). Using mixed models in R, I will analyze relationships between burrow characteristics (depth, area, volume, number of chambers, etc.) and crayfish species, crayfish characteristics, burrow location in habitat, and soil characteristics. The statistical analysis will be done to determine how much variation in burrow characteristics can be partitioned to species, habitat characteristics, or individual crayfish.