Morphological Variation of Rusty Crayfish Orconectes rusticus (Cambaridae) with Gender and Local Scale Spatial Gradients

We tested for the influence of gender, stream, and urbanization on morphological variation in rusty crayfish (Orconectes rusticus) in an east-central Indiana, US watershed. We used geometric morphometrics to characterize shape and tested for differences among and within sites. Males had shallower rostrum, increased head width and length, decreased abdomen and cephalothorax width and length, and increased telson length compared to females. Morphology of males did not vary with stream or along an urban gradient. The morphology of females varied with stream and along an urban gradient. Female shapes from small creek sites were stouter and less fusiform than larger river specimens. Following an urban gradient, females exhibited an increasingly reduced abdominal and telson area and a more fusiform rostrum. Morphological variation is linked with adaptation and subsequent success of aquatic taxa. Disentangling the potential influences on crayfish morphology has implications for improved understanding of ecosystem structure and conservation

State-space models to describe survival of an endemic species in the Little Tennessee River basin

Endemic species are threatened by invasive species, habitat loss, and climate change. Endemic species are also an important group that maintains biodiversity. Understanding population dynamics of endemic species is needed to maintain or restore their populations. Advancements in models that describe population dynamics of endemic species and species of conservation need has been made possible by the application of novel quantitative methods. One such modeling tool is state-space modeling. These models provide a flexible framework to describe population dynamics using simple mortality models and more complex integrated population models. Here we develop a state-space model to describe survival and population size of the Sicklefin Redhorse (Catostomidae: Moxostoma sp.), a species of conservation concern from two rivers located in North Carolina, USA. This model is structured to combine information across similar rivers and to account for complex interactions of sex, time, variable sampling effort, and river discharge. Survival of Sicklefin Redhorse was found to vary by sex, and annual variability was not consistent across rivers. Discharge was negatively related to capture probability for males. Capture probabilities also differed across sex. Population estimates revealed a large difference between sex where males outnumbered females each year in both rivers. We conclude that electrofishing is not an efficient capture method but when used, should consider discharge. Discharge was not included in the survival model, however, the 3 years with the lowest survival in the Little Tennessee River coincided with the three lowest discharge years in the time series. Future work should investigate the difference in survival between the rivers

Geographic information systems habitat associations of large river fish assemblages from side-scan sonar

Access to thesis permanently restricted to Ball State community only.Access to abstract permanently restricted to Ball State community only.Thesis (Ph. D.)Department of BiologyGIS habitat associations of large river fish assemblages from side-scan sonar -- Large river fish assemblage variation during three consecutive years : trophic traits and habitat associations from side-scan sonar -- Silver carp habitat association : a comparison of incident-based electrofishing and radio-tagged fish during three consecutive years

Temporal and Spatial Morphological Variation of Northern Crayfish (Orconectes virilis).

We tested for the influence of gender, stream, and watershed on morphological variation in northern crayfish (Orconectes virilis) in Illinois. Crayfish collections spanning from 1950-present were analyzed from the Illinois Natural History Survey. We used geometric morphometrics to characterize shape and tested for differences among and within sites. Morphological variation is linked with adaptation and subsequent success of aquatic taxa. Disentangling the potential influences on crayfish morphology has implications for improved understanding of ecosystem structure and conservation

Temporal and Spatial Morphological Variation of Northern Crayfish (Orconectes virilis).

We tested for the influence of gender, stream, and watershed on morphological variation in northern crayfish (Orconectes virilis) in Illinois. Crayfish collections spanning from 1950-present were analyzed from the Illinois Natural History Survey. We used geometric morphometrics to characterize shape and tested for differences among and within sites. Morphological variation is linked with adaptation and subsequent success of aquatic taxa. Disentangling the potential influences on crayfish morphology has implications for improved understanding of ecosystem structure and conservation

Fish Assemblages, Substrate, and Current Velocity of the Wabash River.

We used side scan sonar to collect GIS data for a bathymetric map of the entire length of the Wabash River. Bathymetry data were supplemented with water velocity, substrate size, and woody debris in a GIS. Individual fish species were assigned separate layers to allow visualization of habitat patterns with fish occurrences. We used several ordination approaches to test for fish assemblage structure that varies with habitat variables

Morphological Variation of Rusty Crayfish Orconectes rusticus (Cambaridae) with Gender and Local Scale Spatial Gradients

We tested for the influence of gender, stream, and urbanization on morphological variation in rusty crayfish (Orconectes rusticus) in an east-central Indiana, US watershed. We used geometric morphometrics to characterize shape and tested for differences among and within sites. Males had shallower rostrum, increased head width and length, decreased abdomen and cephalothorax width and length, and increased telson length compared to females. Morphology of males did not vary with stream or along an urban gradient. The morphology of females varied with stream and along an urban gradient. Female shapes from small creek sites were stouter and less fusiform than larger river specimens. Following an urban gradient, females exhibited an increasingly reduced abdominal and telson area and a more fusiform rostrum. Morphological variation is linked with adaptation and subsequent success of aquatic taxa. Disentangling the potential influences on crayfish morphology has implications for improved understanding of ecosystem structure and conservation

Fish Assemblages, Substrate, and Current Velocity of the Wabash River.

We used side scan sonar to collect GIS data for a bathymetric map of the entire length of the Wabash River. Bathymetry data were supplemented with water velocity, substrate size, and woody debris in a GIS. Individual fish species were assigned separate layers to allow visualization of habitat patterns with fish occurrences. We used several ordination approaches to test for fish assemblage structure that varies with habitat variables