Research

The ability to understand or predict how an organism will utilize, manipulate, or adapt to its surrounding environment is of tremendous value and importance. Habitat alteration and destruction, overharvesting, invasive species introduction, and increased atmospheric CO2 concentrations are having substantial influences on the environment. Unfortunately, our understanding of the connectivity between a species and its surrounding environment is often incomplete, hindering the abilities of resource managers to accurately predict the impacts or implications of future environmental change, or to assess impediments to restoration and rehabilitation efforts.

My research seeks to improve our understanding of animal – environmental connectivity, and how habitat requirements and interactions change over the course of an animal’s life. Further, through the use of spatially explicit habitat modeling and on-site field surveys, my work looks to explore this connectivity to develop assessment methods to identify impediments to recovery and restoration attempts of species of conservation concern. By developing assessment protocols for species that allow for effective monitoring of status through all stages of an animal’s life, my research provides a framework to evaluate current restoration strategies and to determine future management actions.

Dissertation:

For my dissertation research, I use spatially explicit habitat models and information on fish dispersal and habitat preferences to examine links between lake sturgeon and their surrounding environment. Using this information, I then generate habitat suitability models to identify patches of suitable habitat for young lake sturgeon in hard to survey large river systems, where our understanding of young lake sturgeon behavior is particularly lacking. Information on the quality, quantity, and spatial distribution of these patches is then used to aid in resource management - sponsored restoration efforts of sturgeon in these systems. The specific aims of my dissertation research are 1) to develop early-stage specific habitat suitability models that take into account habitat needs and preferences of lake sturgeon during their first 1 to 2 years of life in large river systems, and 2) to use these models to accurately predict patterns in lake sturgeon – environmental connectivity and identify essential habitat patches in target river systems.

Currently, I am developing habitat models that take into account known patterns of newly hatched lake sturgeon (larvae) dispersal in the large rivers that make up GLCCs (specifically the St. Clair River), and combining this with information on habitat quality and composition in this river. Specifically, input parameters include annual field surveys describing distribution patterns of lake sturgeon larvae as they disperse from their spawning sites of origin, and habitat features such as prey availability, river depth, and river current speed that are present throughout the distribution range of these larvae. These parameters are combined and modeled in a Geological Information System (GIS) format. GIS is a powerful tool in ecology, which enables researchers to project georeferenced data on environmental attribute onto a 2D or 3D landscape and to identify spatial and / or ecological relationships between select features and the organism of interest. The above mentioned features are known to exert a strong influence on age 1 to 2 lake sturgeon distribution in other, smaller rivers, and are believed to exert a similar influence on sturgeon in my research. Model outputs are in the form of spatially explicit maps indicating the quality, quantity, and spatial distribution of areas with varying likelihoods of harboring age 1 to 2 lake sturgeon or possessing suitable habitat features that may attract and support targeted individuals. Initial model results have indicated an abundance of suitable habitat present in my study system and have encouraged a joint venture between myself, the Michigan DNR (MDNR), and the U.S. Fish and Wildlife Service (USFWS) in an attempt to validate model output. In order to ascertain the ability of these models to accurately portray true fish – habitat relationships, additional field surveys are conducted in areas of varying habitat features. Age, location, and habitat characteristics for each captured lake sturgeon at the point of collection are pooled with lake sturgeon surveys conducted by other agencies interested in the lake sturgeon status in the system (MDNR, USFWS).

Additionally, I am developing a sampling protocol to be adapted from the work in my own case system and applied to management efforts on lake sturgeon in other large river systems comprising the GLCCs, specifically the Detroit and Niagara rivers. This protocol draws on outputs of similarly constructed habitat models and stresses a system – specific survey approach rather than a more traditional “one size fits all” strategy as is generally used in large scale management plans.

Successful completion and implementation of these models will enable resource managers to identify areas within these river systems containing essential habitat qualities for young lake sturgeon. A relationship linking sturgeon to these areas can then be investigated which will provide managers with a greater understanding of the link between lake sturgeon and their environment during this crucial period of their life. While these models and sampling methodologies have been specifically designed in the hopes of linking early life stages of lake sturgeon and aiding in rehabilitation efforts in these large rivers, the inherent theoretical framework behind these models; examining stage-specific animal – environmental connectivity, has many applications which can be further developed for use in other systems with other organisms of interest.

Master's Thesis and Bachelors:

As a Master’s student at Auburn University, Auburn, AL., my thesis “Effects of recreational divers on coral reef at Key Largo, FL.” focused on human impacts on the coral reef ecosystems of the Northern Florida Keys, and assessed how current management practices worked to reduce this impact. My thesis addresses the main issue of minimal governmental involvement in regulating recreational diver behavior in the Florida Keys, resulting in local dive shops being heavily responsible for promoting diver behavior that supports reef conservation. My study assessed patterns of dive frequency, diver behavior, and coral damage at selected coral reef sites near Key Largo. Variation in the proportion of damaged corals were determined among sites that varied in dive frequency, which allowed me to assess the relationship between rates of recreational diving and damage to reef corals. Observations of diver behavior were used to examine the connection between currently enforced management practices such as dive briefings given by dive shops, dive guides, and public awareness programs and the varying effects these have on frequencies of diver-coral contact. Furthermore, I am examined dive shops in the NOAA sponsored Blue Star program (shops that have voluntarily agreed to promote sound reef conservation awareness), and compared them with dive shops not in this program. This study was the first to examine these relationships on Florida reefs, and provided an update to the few studies on tourist impact to coral reefs in Florida conducted ˃20 years ago.

My undergrad research at Central Michigan University, Mt. Pleasant, MI., focused on investigating the environmental/biological drivers that determine the composition and function of the microbial community within pitchers of the northern pitcher plant (Sarracenia purpurea). Over the course of this project, I utilized standard molecular techniques such as DNA extraction, polymerase chain reacation (PCR), analyzed microbial community assemblages using Denaturing Gradient Gel Electrophoresis (DGGE) and carried out standard cloning and sequencing techniques. The two main objectives of this project were 1) to determine the ability of the pitcher plant is able to self-control the microbial communities located within the microhabitats (leave, liquid, sediment) of the pitcher bulb, and 2) characterize the immense and unique microbial diversity residing within the pitcher itself and explore how this composition may change in response to increased atmospheric nitrogen gas.

Peer-Review Publications___________________________________________________________________________________________________________________________________________________________________

Krieger, J. R., Lynch, M. A., and J. S. Diana. (In Preparation). Habitat utilization and seasonal shifts in fish assemblage composition of two large Laurentian Rivers. Transactions of the American Fisheries Society.

Young, R., Krieger, J. R., Roseman, E. F., and J. S. Diana. (In Review). Assessing the spatiotemporal distribution of larval lake sturgeon (Acipenser fulvescens) within the St. Clair River delta, Michigan. Journal of Great Lakes Research.

Krieger, J. R., and J. S. Diana. 2016. Development and evaluation of a habitat suitability model for young lake sturgeon (Acipenser fulvescens) in the North Channel of the St. Clair River, MI. Canadian Journal of Fisheries and Aquatic Sciences. 74: 1000-1008. DOI 10.1139/cjfas-2016-0357. Link

Krieger, J. R., and N. E. Chadwick. 2013. Recreational diving impacts and the use of pre-dive briefings as a management strategy on Florida coral reefs. Journal of Coastal Conservation. 17: 179-189. Link

Krieger, J. R., and P. S. Kourtev. 2012. Bacterial diversity in three distinct sub-habitats within the pitchers of the Northern Pitcher Plant, Sarracenia purpurea. FEMS Microbiology Ecology. 79: 555-567. Link

Krieger, J. R., and P. S. Kourtev. 2012. Detection of methanogenic archaea in the pitchers of the Northern Pitcher Plant, Sarracenia purpurea. Canadian Journal of Microbiology. 58: 189-194. Link

Other Publications_____________________________________________________________________________________________________________________________________________________________________________

Krieger, J. R. 2015. “Lake trout, Lake whitefish, Rainbow smelt, Walleye, and Yellow perch – Lake Huron.” Seafood Watch Seafood Report. Monterey Bay Aquarium, Monterey, CA. Available at: Link

Krieger, J. R. 2015. “Lake trout, Lake whitefish, Rainbow smelt, Walleye, and Yellow perch – Lake Michigan.” Seafood Watch Seafood Report. Monterey Bay Aquarium, Monterey, CA. Available at: Link

On-Line Publications__________________________________________________________________________________________________________________________________________________________________________

Krieger, J. R. 2016 (Feb. 18th). Look Out Below! Impacts of Recreational Divers on Coral Reefs. [Web Blog Post]: Link