Small artificial impoundments have big implications for hydrology and freshwater biodiversity

Headwater streams are critical for freshwater ecosystems. Global and continental studies consistently show major dams as dominant sources of hydrological stress threatening biodiversity in the world’s major rivers, but cumulative impacts from small artificial impoundments concentrated in headwater streams have rarely been acknowledged. Using the Murray Darling River basin (Australia)and the Arkansas River basin (USA) as case studies, we examine the hydrological impact of small artificial impoundments. The extent of their influence is significant, altering hydrology in 280 - 380% more waterways when compared to major dams alone. Hydrological impacts are concentrated in smaller streams (catchment area < 100 km2), raising concerns that the often diverse and highly endemic biota found in these systems may be under threat. Adjusting existing biodiversity planning and management approaches to address the cumulative effects of many small and widely distributed artificial impoundments presents a rapidly emerging challenge for ecologically sustainable water management.

How a New Paradigm Explains Topographic Map Drainage System and Erosional Landform Evidence in the Fremont County Royal Gorge Area, Colorado, USA

A new Cenozoic geologic and glacial history paradigm (new paradigm) describes massive and prolonged continental ice sheet meltwater floods that eroded the Colorado Royal Gorge area and surrounding regions and which were diverted in east, northeast, and even north directions as uplift of a thick ice sheet created deep &ldquo;hole&rdquo; rim gradually occurred (the thick ice sheet was located where North American ice sheets are usually recognized to have existed). A deep &ldquo;hole&rdquo; rim segment followed what is now the northern and central Colorado east-west continental divide southward to the Arkansas River headwaters area and then continued south along the Sangre de Cristo Mountains crestline to at least the Purgatoire River-Canadian River drainage divide and may have continued east from that point along a less well-defined zone beginning with what is now the Purgatoire River-Canadian River drainage divide. Diverging and converging valley complexes, barbed tributaries, and Arkansas River and other drainage route direction changes (easily seen on United States Geological Survey detailed topographic maps) are interpreted to have developed as the south-oriented floodwaters first flowed across the rising deep &ldquo;hole&rdquo; rim to reach the south- and southeast-oriented Rio Grande River drainage basin and were subsequently blocked by deep &ldquo;hole&rdquo; rim uplift and diverted to flow in east, northeast, and north directions. The accepted Cenozoic geologic and glacial history paradigm (accepted paradigm) has to date been unable to satisfactorily explain the detailed topographic map drainage system and erosional landform evidence and the new and accepted paradigms are incommensurable and lead to quite different Cenozoic geologic and glacial histories.

The Battle of Helena, the Little Rock Campaign, and the Capture of Fort Smith, 1863

The Battle of Helena, the Little Rock Campaign, and the capture of Fort Smith led to Union control over the Arkansas River Valley and most of Arkansas to the north of the river. Militarily this resulted in impeding Confederate operations in Missouri, the establishment of a potential base of operations for Union campaigns in Texas, and easier logistical support for Union forces in Indian Territory. A major result of these movements was the emancipation of thousands of slaves. Politically they brought a restoration of a pro-Union government in Arkansas. The occupation of Little Rock produced renewed economic prosperity and, under the benevolent policies of Union Maj. Gen. Frederick Steele, a return of normal social activity among the civilian population, though producing privation and disruption of gender and age roles in the surrounding countryside.

Production Matters

Recent absorbed residue studies have confirmed that ceramic and shell containers were used for consuming Datura in precolumbian times. Until now, no one has identified what tools precolumbian people used to produce a concentrated hallucinogenic concoction. In this study, we used mass spectrometry to identify Datura residues (a flowering plant with hallucinogenic properties) in two late precolumbian composite bottles from the Central Arkansas River valley. Unlike the construction of most Mississippian bottles, the bottles in this study are unique because ceramic disks with a series of concentric perforations were incorporated in the bottles at the juncture of the bottle neck with the globular portion of the body. The organic residue analysis revealed Datura residues in both bottles. We argue that the internal clay disks served as strainers that allowed Datura producers to separate the hallucinogenic alkaloids from the Datura flower to produce a powerful liquid beverage.

Ecological genomics of divergence, admixture, and fitness in the smallmouth bass (Micropterus dolomieu)

The Smallmouth Bass (Micropterus dolomieu) is one of the most highly targeted sport fishes in the world. Anglers vie for the opportunity to catch Smallmouth Bass recreationally and competitively, spending billions of dollars every year on travel, equipment, and conservation permits. Along with their extreme popularity, they are of central importance in their native ecosystems throughout central and eastern North America. They are voracious apex predators, controlling top-down food web dynamics among fishes and invertebrates in both streams and natural lakes, and they act as obligate hosts in the life cycles of several freshwater mussels. A great deal is known about the general ecology of Smallmouth Bass and their role in aquatic communities across their extensive native distribution. Much less is known about levels and distribution of diversity within the species. In 1940, Carl Hubbs and Reeve Bailey published descriptions of two distinct subspecies: the Northern Smallmouth Bass (M. d. dolomieu), inhabiting the central and eastern portion of the range, and the Neosho Smallmouth Bass (M. d. velox), which is range-restricted to the Arkansas River Basin in the Central Interior Highlands. While the subspecies classification was largely accepted among taxonomists, it was predicated on only a few subtle morphological traits, including differences in coloration, body size, and the presence of glossohyal teeth. Researchers began to investigate genetic divergence among Smallmouth Bass populations at the end of the twentieth century. Some genetic structure has been detected, but the overall diversity and the evolutionary forces generating contemporary patterns have been considered extremely complex and therefore unresolved, especially where the Neosho and Northern subspecies ranges meet in the Central Interior Highlands. To address the need for a robust understanding of the divergence and evolution history of Smallmouth Bass in the Central Interior Highlands, I addressed three broad areas concerning the phylogeography and conservation of the species using a combination of morphological, genetic, and genomic data: 1) patterns of genetic and morphological differentiation between the Neosho and Northern Smallmouth Bass subspecies, 2) lineage diversification and the extent and origins of admixture within the subspecies, and 3) effects of admixture on individual growth and fitness in two streams within the Neosho Smallmouth Bass native range. Using neutral microsatellite markers and a combination of three independent Bayesian analysis methods, I detected complex and hierarchical population structure of Smallmouth Bass in the Central Interior Highlands. The broadest level of structure indicated two distinct genetic clusters corresponding to the Neosho and Northern subspecies, but with substantial and heterogenous patterns of admixture within some streams in the Neosho native range. At finer levels of structure, clusters corresponded to river drainages and to potentially distinct populations within drainages. The Northern and Neosho subspecies were morphologically distinct overall based on principal component analysis of five morphometric traits, but they significantly differed only in head length. Based on genome-wide variation at over 50,000 single nucleotide polymorphisms, the Neosho and Northern subspecies represented two diverged, monophyletic clades, each comprising two additional monophyletic lineages. Populations in Big Piney Creek and the Illinois Bayou within the Neosho range also showed signatures of local adaptation based on outlier FST analysis. Admixture in the Illinois River system within the Neosho range originated from a hatchery strain of Northern Smallmouth Bass found in Skiatook Lake, Oklahoma, while admixture in the Elk River, upper Arkansas River tributaries, and the Illinois Bayou and Big Piney Creek system originated from the White River in the Northern range. Demographic analysis revealed that admixture in these streams has occurred on different time scales, in some cases likely due to historic migration, and in other cases likely due to secondary contact, possibly as a result of anthropogenic introductions. In Big Sugar Creek and the Elk River, two Neosho Smallmouth Bass native streams known to be admixed with White River Northern Smallmouth Bass, individual growth did not differ between genetically pure Neosho, pure Northern, or admixed fish. However, in the Elk River alone, average length-at-infinity (maximum length) was lower for admixed fish than for either pure Neosho or pure Northern fish. We also found a significant negative relationship between multi-locus heterozygosity (based on fourteen microsatellite loci) and body condition, suggesting that increased intermixing may be causing outbreeding depression in these streams. The Neosho and Northern Smallmouth Bass constitute highly differentiated, locally adapted, and independently evolving lineages in the Central Interior Highlands. Despite divergence, there are also complex and extensive patterns of admixture in the Neosho range which may be contributing to lower fitness in two Neosho Smallmouth Bass streams. It will be crucial to consider these patterns and their potential outcomes in the development of management protocols for the preservation of endemic diversity within this economically and ecologically vital sportfish.

“We got in the pilot program to learn from it:” Features of Social Learning in Drought Contexts Along the Arkansas River in Colorado

Unintended consequences from decisions made in one part of a social-ecological system (SES) in response to climate hazards can magnify vulnerabilities for others in the same system. Yet anticipating or identifying these cascades and spillovers in real time is difficult. Social learning is an important component of adaptation that has the ability to facilitate adaptive capacity by mobilizing multiple actors around a common resource to manage collectively in ways that build local knowledge, reflective practices, and a broader understanding of contexts for decisions. While the foundations of social learning in resource management have been theorized in the literature, empirical examples of unintended consequences that trigger social learning are few. This article analyzes two cases of drought decisions made along the Arkansas River Basin in Colorado; in each, social learning occurred after actors experienced unanticipated impacts from others’ decisions. Methods include interviews with actors, both individual and institutional representatives of different sectors (e.g. recreation, agriculture, etc.), and a review of relevant historical and policy documents. The study identifies four features of social learning that aided actors’ responses to unanticipated consequences: first, governance structures that facilitated more holistic river management; second, relationship boundaries that expanded beyond small scale decisions to capture interactions and emergent problems; third, knowledge of others’ previous experience, whether direct or indirect; and fourth, creation of spaces for safer experimentation with adaptation changes. Results identify empirical examples of actors who successfully learned to adapt together to unexpected consequences and thus may provide insight for others collectively managing drought extremes.