Genetic isolation and morphological divergence mediated by high-energy rapids in two cichlid genera from the lower Congo rapids

<p>Abstract</p> <p>Background</p> <p>It is hypothesized that one of the mechanisms promoting diversification in cichlid fishes in the African Great Lakes has been the well-documented pattern of philopatry along shoreline habitats leading to high levels of genetic isolation among populations. However lake habitats are not the only centers of cichlid biodiversity - certain African rivers also contain large numbers of narrowly endemic species. Patterns of isolation and divergence in these systems have tended to be overlooked and are not well understood.</p> <p>Results</p> <p>We examined genetic and morphological divergence among populations of two narrowly endemic cichlid species, <it>Teleogramma depressum </it>and <it>Lamprologus tigripictilis</it>, from a 100 km stretch of the lower Congo River using both nDNA microsatellites and mtDNA markers along with coordinate-based morphological techniques. In <it>L. tigripictilis</it>, the strongest genetic break was concordant with measurable phenotypic divergence but no morphological disjunction was detected for <it>T. depressum </it>despite significant differentiation at mtDNA and nDNA microsatellite markers.</p> <p>Conclusions</p> <p>The genetic markers revealed patterns of philopatry and estimates of genetic isolation that are among the highest reported for any African cichlid species over a comparable geographic scale. We hypothesize that the high levels of philopatry observed are generated and maintained by the extreme hydrology of the lower Congo River.</p

Congo River Lamprologus

40 p. : ill., maps ; 26 cm.Electronic version available in portable document format (PDF).Includes bibliographical references (p. 38-40).The Congo River Lamprologus are revised and two new species are described. Lamprologus teugelsi, n.sp., from Malebo Pool and the lower Congo River rapids, and L. tigripictilis, n.sp., from the lower Congo River rapids, are readily distinguished from the remaining Congo River Lamprologus based on counts, measurements, osteology, and color pattern. Monophyly of the Congo River Lamprologus species is tentatively accepted and a key to the group is provided. All available collection localities for re-identified Lamprologus material from the Congo River are plotted for each species. Maps of collection localities reveal large distributional voids, suggesting that Congo River lamprologine diversity remains incompletely sampled

Remarkable Response of Native Fishes to Invasive Trout Suppression Varies With Trout Density, Temperature, and Annual Hydrology

Recovery of imperiled fishes can be achieved through suppression of invasives, but outcomes may vary with environmental conditions. We studied the response of imperiled desert fishes to an invasive brown (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) suppression program in a Colorado River tributary, with natural flow and longitudinal variation in thermal characteristics. We investigated trends in fish populations related to suppression and tested hypotheses about the impacts of salmonid densities, hydrologic variation, and spatial–thermal gradients on the distribution and abundance of native fish species using zero-inflated generalized linear mixed effects models. Between 2012 and 2018, salmonids declined 89%, and native fishes increased dramatically (∼480%) once trout suppression surpassed ∼60%. Temperature and trout density were consistently retained in the top models predicting the abundance and distribution of native fishes. The greatest increases occurred in warmer reaches and in years with spring flooding. Surprisingly, given the evolution of native fishes in disturbance-prone systems, intense, monsoon-driven flooding limited native fish recruitment. Applied concertedly, invasive species suppression and efforts to mimic natural flow and thermal regimes may allow rapid and widespread native fish recovery

Exploring Metapopulation-Scale Suppression Alternatives for a Global Invader in a River Network Experiencing Climate Change

Invasive species can dramatically alter ecosystems, but eradication is difficult, and suppression is expensive once they are established. Uncertainties in the potential for expansion and impacts by an invader can lead to delayed and inadequate suppression, allowing for establishment. Metapopulation viability models can aid in planning strategies to improve responses to invaders and lessen invasive species’ impacts, which may be particularly important under climate change. We used a spatially-explicit metapopulation viability model to explore suppression strategies for ecologically-damaging invasive brown trout (Salmo trutta), established in the Colorado River and a tributary within Grand Canyon National Park. Our goals were to: 1) estimate the effectiveness of strategies targeting different life stages and subpopulations within a metapopulation, 2) quantify the effectiveness of a rapid response to a new invasion relative to delaying action until establishment; and 3) estimate whether future hydrology and temperature regimes related to climate change and reservoir management affect metapopulation viability and alter the optimal management response. We included scenarios targeting different life-stages with spatially-varying intensities of electrofishing, redd destruction, incentivized angler harvest, piscicides, and a weir. Quasi-extinction (QE) was obtainable only with metapopulation-wide suppression targeting multiple life-stages; subpopulations were most sensitive to age-0 and large adult mortality. The duration of suppression needed to reach QE for a large established subpopulation was triple compared to a rapid response to a new invasion. Isolated subpopulations were vulnerable to suppression; however, connected tributary subpopulations enhanced metapopulation persistence by serving as climate refuges. Water shortages driving changes in reservoir storage and subsequent warming would cause brown trout declines, but metapopulation QE was only achieved by re-focusing and increasing suppression. Our modeling approach improved our understanding of invasive brown trout metapopulation dynamics, which could lead to more focused and effective invasive species suppression strategies, and ultimately, maintenance of populations of endemic fishes

The Influence of Manga on the Graphic Novel

This material has been published in The Cambridge History of the Graphic Novel edited by Jan Baetens, Hugo Frey, Stephen E. Tabachnick. This version is free to view and download for personal use only. Not for re-distribution, re-sale or use in derivative works. © Cambridge University PressProviding a range of cogent examples, this chapter describes the influences of the Manga genre of comics strip on the Graphic Novel genre, over the last 35 years, considering the functions of domestication, foreignisation and transmedia on readers, markets and forms

The first case of aggressive mimicry among lamprologines in a new species of Lepidiolamprologus (Perciformes: Cichlidae) from Lake Tanganyika

Schelly, Robert, Takahashi, Tetsumi, Bills, Roger, Hori, Michio (2007): The first case of aggressive mimicry among lamprologines in a new species of Lepidiolamprologus (Perciformes: Cichlidae) from Lake Tanganyika. Zootaxa 1638: 39-49, DOI: 10.5281/zenodo.17961

Chapter 1: Introduction to a research agenda for environmental management – Through transdisciplinary, social science-rich environmental governance research

Forty-seven years after the first Earth Day, environmental management problems remain some of humanity’s greatest unsolved challenges. Climate change, resource scarcity, air and water pollution, and biodiversity losses continue and are, in some cases, worsening over time (Berkes et al., 2003). Developing the capacity to success-fully understand these problems and their solutions therefore remains an important research agenda item