Daniel K. Gibson-Reinemer

Elemental signatures in otoliths of hatchery rainbow trout (Oncorhynchus mykiss): distinctiveness and utility for detecting origins and movement

Otolith chemistry in freshwater has considerable potential to reveal patterns of origin and movement, which would benefit traditional fisheries management and provide a valuable tool to curb the sp...

Widespread and enduring demographic collapse of invasive common carp (Cyprinus carpio) in the Upper Mississippi River System

Populations of invasive species that undergo rapid expansions after establishment in a new system can also be subject to collapse. Although the dynamics of the establishment and expansion phases and their ecological effects are well documented, substantially fewer studies document collapses despite their importance for understanding invasion dynamics. Two long-term fish monitoring programs sample the fish assemblage of the Upper Mississippi River System. These data provide an opportunity to document the collapse of common carp (Cyprinus carpio), a globally invasive freshwater fish species. Here we describe their population trajectory over several decades and examine several hypotheses to explain the decline, including: boom-bust population dynamics; suppression by native predators; resource exhaustion; improvements in environmental conditions; and disease. The observed trends appear to be most consistent with the hypothesis that disease was the most important factor contributing to the collapse. In particular, cyprinid herpesviruses have been shown to affect common carp in a manner consistent with the observed decreases in catch rates and increases in size distributions. The apparent role of a viral agent in causing the decline of common carp across one of the largest river basins in North America suggests similar collapses may occur elsewhere.

Hydrology controls recruitment of two invasive cyprinids: bigheaded carp reproduction in a navigable large river

In the Mississippi River Basin of North America, invasive bigheaded carp (silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis, also referred to as Asian carp) have spread rapidly over the past several decades. In the Illinois River, an important tributary of the Upper Mississippi River, reproduction appears to be sporadic and frequently unsuccessful, yet bigheaded carp densities in this river are among the highest recorded on the continent. Understanding the causative factors behind erratic recruitment in this commercially-harvested invasive species is important for both limiting their spread and managing their harvest. We analyzed weekly catch records from 15 years of a standardized monitoring program to document the emergence of age-0 bigheaded carp in relation to environmental conditions. The appearance of age-0 fish was generally linked to hydrographic attributes, which probably serve as a cue for spawning. However, we found profound differences in the number of age-0 fish among years, which varied by as much as five orders of magnitude in successive years. The strong link between summer flooding and age-0 fish production we observed emphasizes the importance of understanding the hydrologic context in which sustained invasions occur. Despite evidence of sporadic recruitment, bigheaded carp populations in the Illinois River appear to be consistent or increasing because of particularly strong, episodic year classes.

Ecological Recovery of a River Fish Assemblage following the Implementation of the Clean Water Act

The twentieth century spanned an era that included nadirs in environmental quality and subsequent efforts to improve ecological conditions. The Illinois Waterway, a large river system in Illinois, experienced prolonged degradation followed by a dramatic recovery. In the 1950s, a standardized sampling program was initiated that has continued for six decades. The resulting record documents profound ecological changes, demonstrating the potential for river ecosystems to recover following the successful implementation of large-scale policies, notably the Clean Water Act. Over six decades, native species diversity has increased, and one of the most prolific invasive fish species has collapsed. In addition, the sampling record highlights the recovery of socioeconomically valuable sport-fish populations. We examined the causes and consequences of change in a large river using data from a long-term monitoring program with unique spatial and temporal extent. The trends documented in the Illinois Waterway are relevant for the restoration of river systems worldwide.

Estimating the Effects of Environmental Variables and Gear Type on the Detection and Occupancy of Large-River Fishes in a Standardized Sampling Program Using Multiseason Bayesian Mixture Models

AbstractSampling in non-wadeable rivers presents methodological challenges for monitoring fish species. Changing environmental conditions may affect the ability to accurately capture species (i.e., detection) and consequently may lead to inappropriate inferences on occupancy rates. We used hierarchical Bayesian multiseason mixture models to estimate occupancy and detection of 41 of 52 fish species in the Kankakee River, Illinois, by using data from a standardized monitoring program. Fish were sampled with AC boat electrofishing and shoreline seining over 7 years. Some centrarchids (e.g., Smallmouth Bass Micropterus dolomieu) were efficiently sampled by boat electrofishing, whereas most other species had low detection probabilities. Moderate changes in environmental conditions, such as water velocity and temperature, produced moderate changes in detection and occupancy. Generally, when species had high detection probabilities, changes in environmental conditions produced relatively small changes in the est...

A Vacant Niche: How a Central Ecological Concept Emerged in the 19th Century

The niche is a central concept in ecology. The ecological niche has long been viewed as a metaphor (e.g., Haefner 1980), but what has not been fully appreciated about the niche is that it was a metaphor with a long history and particular entailments. Ecologists frequently describe the niche concept as developed independently by Joseph Grinnell, citing his 1917 paper on California thrashers, and Charles Elton, in his 1927 book, Animal Ecology (e.g., Odum 1971, Hutchinson 1978, Real and Levin 1991). Far less frequently, a manuscript on evolution in lady-beetles by Roswell Johnson (Johnson 1910) is credited with first using the term several years before Grinnell. Johnson (1910) wrote, “one expects the different species in a region to occupy different niches in the environment,” and for this, he is credited as the first person to introduce the term to ecology (Gaffney 1973, Hutchinson 1978). Importantly, the niche concept was imprecisely defined in the first decades after it was introduced. Hutchinson (1978) wrote that, although both Grinnell and Johnson used the term niche, they were “never quite clear what sort of unit [the niche] was.” Later, with regard to the competitive exclusion principle, Hutchinson commented that the term niche was still used “without there being a very clear idea as to what the thing was in which the two closely allied species did not coexist” (Hutchinson 1978). A contemporary definition of the niche is “the physical and biological conditions that the species needs to grow, survive, and reproduce” (Cain et al. 2008). This modern view combines the physical conditions emphasized by Grinnell and the biotic interactions emphasized by Elton.

Tracking the Trajectory of Change in Large River Fish Communities Over 50 Y

Abstract Multivariate statistics are commonly used by ecologists to study spatial and temporal community dynamics to better inform management decisions. Since these methods are a universal tool to analyze data, it is important to assess their effectiveness using long-term datasets in well-studied systems. The objectives of this study were to identify trends in the fish communities and to characterize the community trajectory (i.e., directional or nondirectional) of the Illinois River, a large tributary to the Mississippi River, using nonmetric multidimensional scaling (NMDS). Although NMDS has been used to evaluate community trajectory in multivariate space over time in smaller rivers, there has been less attention given to larger rivers, which may exhibit different dynamics. To evaluate changes in large river fish communities, we used a long-term electrofishing monitoring dataset (1957–2013) that includes fish abundance data from six reaches of the Illinois River, Illinois, U.S.A. Temporal changes in Illinois River fish communities were evident in NMDS ordinations. Larger changes in NMDS ordinations were associated with improving water quality conditions, whereas the invasion of bigheaded carp (silver carp Hypophthalmichtys molitrix and bighead carp H. nobilis) produced smaller and less variable changes. Across all six reaches of the Illinois River, the trajectory of fish communities was directional in multivariate space, with no return to an initial or predisturbance condition. Community trajectory in larger and more heavily-modified rivers may be substantially different and more complex than that of smaller and less heavily modified rivers.