Lauren J. Chapman

Lauren J. Chapman
McGill University | McGill · Department of Biology

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248
Publications
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Publications

Publications (248)
Article
Predation risk exerts significant pressure on the survival of prey species and has many indirect impacts on their habitat use, energy allocation, and community dynamics. Prey must consistently assess their surroundings by using multiple information sources to monitor predation risk and respond accordingly. In aquatic environments, chemical signals...
Article
Full-text available
Lake Nabugabo is a small satellite lake separated from Lake Victoria by hypoxic swamps that impose a biogeographic barrier to fish assemblages. Some species occur exclusively in Nabugabo while others show high differentiation across this barrier, yet air-breathing fishes show nearly zero genetic differentiation between the two lakes. We hypothesize...
Article
Freshwater organisms face multiple threats to their ecosystems, including warming associated with climate change and low dissolved oxygen (environmental hypoxia), which are both increasing in frequency and extent in freshwater systems. Understanding tolerance thresholds for these environmental stressors as well as the plasticity of responses is the...
Article
High turbidity and elevated water temperature are environmental stressors that can co-occur in freshwater ecosystems such as when deforestation increases solar radiation and sedimentary runoff. However, we have limited knowledge about their combined impacts on fish behaviour and physiology. We explored independent and interactive effects of sedimen...
Article
Elevated water temperatures and low dissolved oxygen (hypoxia) are pervasive stressors in aquatic systems that can be exacerbated by climate change and anthropogenic activities, and there is growing interest in their interactive effects. To explore this interaction, we quantified the effects of acute and long‐term hypoxia exposure on the critical t...
Presentation
Dissolved oxygen is a key environmental parameter for aquatic life. In two sets of experiments we evaluated the effect of long-term changes in the dissolved oxygen environment on the morpho-physiology and behaviour of the weakly electric fish Petrocephalus degeni. First, we captured fish from a severely hypoxic habitat in Uganda and acclimated them...
Article
Full-text available
The role of phenotypic plasticity during colonization remains unclear due to the shifting importance of plasticity across timescales. In the early stages of colonization, plasticity can facilitate persistence in a novel environment; but over evolutionary time, processes such as genetic assimilation may reduce variation in plastic traits such that s...
Article
Full-text available
Natural variation in environmental turbidity correlates with variation in the visual sensory system of many fishes, suggesting that turbidity may act as a strong selective agent on visual systems. Since many aquatic systems experience increased turbidity due to anthropogenic perturbations, it is important to understand the degree to which fish can...
Article
Full-text available
Although some lineages of animals and plants have made impressive adaptive radiations when provided with ecological opportunity, the propensities to radiate vary profoundly among lineages for unknown reasons. In Africa’s Lake Victoria region, one cichlid lineage radiated in every lake, with the largest radiation taking place in a lake less than 16,...
Article
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Hypoxia is a widespread environmental stressor that shapes fish physiology and morphology. Plasticity in traits that improve oxygen uptake and delivery or reduce oxygen requirements may be critical for fish to cope with fluctuating dissolved oxygen (DO) conditions in their natural habitat or adapt to new environments. In this study, we characterize...
Article
Anthropogenic environmental degradation has led to an increase in the frequency and prevalence of aquatic hypoxia (low dissolved oxygen concentration, DO), which may affect habitat quality for water-breathing fishes. The weakly electric black ghost knifefish, Apteronotus albifrons, is typically found in well-oxygenated freshwater habitats in South...
Chapter
Freshwater organisms face multiple threats associated with habitat degradation, pollution, and eutrophication, in addition to overharvesting and species invasions. Furthermore, there is mounting evidence that freshwaters are highly sensitive to climate change. This chapter provides an overview of contemporary environmental changes in inland waters...
Article
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Inland fisheries support the livelihoods of millions of people in riparian communities worldwide but are influenced by increasing climate variability and change. Freshwater fishing societies are among the most vulnerable to climate change given their dependence on highly threatened aquatic resources. As climate change intensifies, building adaptive...
Article
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Many of the world’s most biodiverse regions are found in the poorest and second most populous continent of Africa; a continent facing exceptional challenges. Africa is projected to quadruple its population by 2100 and experience increasingly severe climate change and environmental conflict—all of which will ravage biodiversity. Here we assess conse...
Article
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To understand animal ecology, observation of wildlife in the natural habitat is essential, but particularly challenging in the underwater realm. Weakly electric fishes provide an excellent opportunity to overcome some of these challenges because they generate electric organ discharges (EODs) to sense their environment and to communicate, which can...
Article
Fishing pressure can have strong impacts on fish populations, driving declines in abundance and, occasionally, changing life history traits. However, much of our current understanding of these phenomena derives from studies conducted decades or even centuries after the onset of fishing. Newly established fisheries provide an excellent opportunity t...
Chapter
For fishes, the availability of dissolved oxygen (DO) can affect performance and fitness traits and influence distribution patterns. Hypoxia occurs naturally in habitats characterized by low mixing and/or light limitation such as dense wetlands and profundal zones of deep lakes. In addition, human activities are increasing the frequency and extent...
Article
Full-text available
Effective conservation requires that species recovery measures are informed by rigorous scientific research. For imperilled freshwater fishes and mussels in Canada, numerous research gaps exist, in part owing to the need for specialized research methods. The Canadian Freshwater Species at Risk Research Network (SARNET) was formed and identified or...
Article
Full-text available
Understanding population-level habitat requirements is important for the effective conservation of imperilled species, especially for those with fragmented distributions. This study examined fine-scale distribution of the threatened pugnose shiner (Notropis anogenus) in the upper St. Lawrence River, Ontario, Canada. Occupancy modelling, multivariat...
Article
Full-text available
Critical thermal maximum (CTmax) is often used as an index of upper thermal tolerance in fishes; however, recent studies have shown that some fishes exhibit agitation or avoidance behavior well before the CTmax is reached. In this study, we quantified behavioral changes during CTmax trials in two Amazonian cichlids, Apistogramma agassizii and Meson...
Article
• Climate change has emerged as an increasingly important threat to freshwater systems. To cope with rapidly changing thermal regimes, freshwater fishes must either relocate or adjust through genetic adaptation and/or phenotypic plasticity. Short-term responses to elevated water temperature have been well studied in freshwater fishes; however, far...
Article
Full-text available
For freshwater fishes, elevated water temperatures associated with climate warming and hypoxia can co-occur and are likely to interact as both affect oxidative metabolism. We quantified the effects of acclimation to elevated temperature and hypoxia on the thermal tolerance of pugnose shiner (Notropis anogenus), a cyprinid fish threatened in its Can...
Article
Full-text available
Anthropogenic environmental degradation has led to an increase in the frequency and prevalence of aquatic hypoxia (low dissolved oxygen concentration, DO), which may affect habitat quality for water-breathing fishes. The weakly electric black ghost knifefish, Apteronotus albifrons, is typically found in well-oxygenated freshwater habitats in South...
Article
Full-text available
Foundation species structure communities by creating habitat and modifying environmental conditions, and there is increasing interest in how foundation species, such as corals and mangroves, interact with one another as these interactions can have cascading effects on diversity and abundance of associated organisms. Given recent reports of corals l...
Article
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We tested whether thermal tolerance and aerobic performance differed between two populations of Nile perch (Lates niloticus) originating from the same source population six decades after their introduction into two lakes in the Lake Victoria basin in East Africa. We used short‐term acclimation of juvenile fish to a range of temperatures from ambien...
Article
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Phenotypic responses to the environment may be controlled via cytosine methylation (5mC) and its effects on gene expression. We test whether hypoxia influences plastic or heritable changes in the quantity of 5mC in the genomes of a widespread African cichlid, the Egyptian mouth-brooder, Pseudocrenilabrus multicolor (Schöller, 1903). Fish were colle...
Article
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Some of the most dramatic and well-studied impacts of introduced predators involve their ecological effects on native prey communities. However, how native predators respond to introduced predators has received less attention. Here, we examined the potential impacts of an introduced predatory fish (Cichla monoculus, the peacock bass) on the diet an...
Article
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Even though the idea that modes of speciation other than allopatric speciation are possible in nature is now widespread, compelling examples of ecological speciation in sympatry remain rare. We studied an undescribed radiation of haplochromine cichlids in a young crater lake in western Uganda, and in the small river that is nearby but has currently...
Article
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Aquatic ecosystems in tropical regions remain understudied and their long-term dynamics poorly understood. In East Africa, a better understanding of how natural communities of primary producers in small freshwater ecosystems respond to climatic variability is needed to improve management and conservation of aquatic resources. This study explored th...
Article
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Equatorial fishes, and the critically important fisheries based on them, are thought to be at-risk from climate warming because the fishes have evolved in a relatively aseasonal environment and possess narrow thermal tolerance windows that are close to upper thermal limits. We assessed survival, growth, aerobic performance and critical thermal maxi...
Article
• Land use changes can strongly influence stream ecosystems, yet these effects remain poorly documented in many hotspots of deforestation such as tropical Africa. The few studies conducted in this region have mostly focused on structural aspects of stream integrity; sparse data are available for key ecosystem processes such as ecosystem metabolism...
Article
Full-text available
Fishes faced with novel thermal conditions often modify physiological functioning to compensate for elevated temperatures. This physiological plasticity (thermal acclimation) has been shown to improve metabolic performance and extend thermal limits in many species. Adjustments in cardiorespiratory function are often invoked as mechanisms underlying...
Article
Fruiting, flowering, and leaf set patterns influence many aspects of tropical forest communities, but there are few long-term studies examining potential drivers of these patterns, particularly in Africa. We evaluated a 15-year dataset of tree phenology in Kibale National Park, Uganda, to identify abiotic predictors of fruit phenological patterns a...
Article
In ectotherms, anthropogenic warming often increases energy requirements for metabolism, which can either impair growth (when resources are limiting) or lead to higher predator feeding rates and possibly stronger top–down trophic interactions. However, the relative importance of these effects in nature remains unclear because: (1) thermal adaptatio...
Article
Prenatal exposure to environmental endocrine disruptors can affect development and induce irreversible abnormalities in both humans and wildlife. The northern part of Kibale National Park, a mid-altitude rainforest in western Uganda, is largely surrounded by industrial tea plantations and wildlife using this area (Sebitoli) must cope with proximity...
Article
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Increasing water temperatures due to anthropogenic climate change are predicted to negatively impact the aerobic metabolic performance of aquatic ectotherms. Specifically, it has been hypothesized that thermal increases result in reductions in aerobic scope (AS), which lead to decreases in energy available for essential fitness and performance func...
Article
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Understanding the cross-scale nature of how natural resource trading links to local extraction patterns remains a topic of great relevance to stewardship and sustainable use of ecological systems. Microeconomic influences on a society’s pattern of smallscale natural resources utilization can exacerbate resource overuse, especially under increased p...
Article
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Increased sedimentary turbidity associated with human activities is often cited as a key stressor contributing to the decline of fishes globally. The mechanisms underlying negative effects of turbidity on fish populations have been well documented, including effects on behavior (e.g. visual impairment) and/or respiratory function (e.g. clogging of...
Article
Full-text available
Key to predicting the response of fishes to climate change is quantifying how close fish are to their critical thermal limits in nature and their ability to adjust their thermal sensitivity to maintain performance. Here, we evaluated the effects of body size and habitat on aerobic scope (AS) and thermal tolerance of Nile perch Lates niloticus (L.),...
Article
Full-text available
The introduction of the large piscivorous Nile perch Lates niloticus (L.) into Lake Nabugabo, Uganda, coincided with a collapse of the native fish community and the development of a fishing industry dominated by Nile perch. Some native fish have persisted in the face of Nile perch predation through use of hypoxic wetlands that may serve as both str...
Article
Full-text available
As climate warming threatens the persistence of many species and populations, it is important to forecast their responses to warming thermal regimes. Climate warming often traps populations in smaller habitat fragments, not only changing biotic parameters, but potentially decreasing adaptive potential by decreasing genetic variability. We examined...
Article
Full-text available
Species that cross strong environmental gradients are expected to face divergent selective pressures that can act on sexually-selected traits. In the present study, we examine the role of hypoxia and carotenoid availability in driving divergence in two sexually-selected traits, male colour and reproductive behaviour, in the African cichlid Pseudocr...
Article
Full-text available
Land use changes such as deforestation and agricultural expansion strongly affect stream biodiversity, with several studies demonstrating negative impacts on stream alpha diversity. Effects of forest conversion on stream beta diversity are much harder to predict, both because empirical studies are few and because competing theories suggest opposite...
Article
Full-text available
Rising water temperature associated with climate change is increasingly recognized as a potential stressor for aquatic organisms, particularly for tropical ectotherms that are predicted to have narrow thermal windows relative to temperate ectotherms. We used intermittent flow resting and swimming respirometry to test for effects of temperature incr...
Article
Periodicity and timing of opaque zone formation in otoliths of introduced redbelly tilapia, Tilapia zillii (Gervais), in Crater Lake Nkuruba, Uganda, were validated using marginal increment. Age and growth were assessed through readings of biannuli in thin-sectioned sagittal otoliths. Deposition of opaque zone formation in T. zillii otoliths was bi...
Article
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This study focused on variation in fish mercury (Hg) concentrations in 185 Nile perch (Lates niloticus) samples collected across four different habitat types in Lake Nabugabo, Uganda, a tropical lake located proximate to Lake Victoria. We quantified the stomach contents of Nile perch using the % index of relative importance, as well as, nitrogen an...
Article
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Tropical inland fishes are predicted to be especially vulnerable to thermal stress because they experience small temperature fluctuations that may select for narrow thermal windows. In this study, we measured resting metabolic rate (RMR), critical oxygen tension (Pcrit) and critical thermal maximum (CTMax) of the widespread African cichlid (Pseudoc...
Article
Aquatic hypoxia (low oxygen) provides a useful system for exploring ecological and evolutionary consequences of living under extreme conditions. It is also an environmental stressor of accelerating interest due to human activities that have increased the extent of hypoxic waters on a global scale. This chapter characterizes the distribution of hypo...
Chapter
Many inland capture fisheries are threatened by intensive fishing and degradation of water quality, both of which stem ultimately from high human population growth rates. There is a growing body of evidence that fishing, by imposing high selective mortality, can lead to changes in life history traits of harvested fish species that may in turn alter...
Article
Human activities, such as species introductions, are dramatically and rapidly altering natural ecological processes, and often result in novel selection regimes. To date, we still have a limited understanding of the extent to which such anthropogenic selection may be driving contemporary phenotypic change in natural populations. Here we test whethe...
Article
The methylated form of mercury (methylmercury) is a potent neurotoxicant and a contaminant of concern for fisheries because of its potential effects on ecosystem and human health. In Africa, inland fisheries are a crucial component of food and economic security, yet little information is available on Hg contamination trends. The authors compiled pu...
Article
Full-text available
2014. Coupled human and natural system dynamics as key to the sustainability of Lake Victoria's ecosystem services. Ecology and Society 19(4):
Article
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External body colour is an important trait contributing to phenotypic diversity and individual fitness in fish species. In this study, we use a combination of experimental techniques and field observations to examine patterns of colour divergence in the introduced Nile perch population of Lake Nabugabo, Uganda. We aim to determine whether the propo...
Article
Introduced species can have profound direct ecological impacts on native species, yet their potential indirect effects remain relatively unexplored. For instance, introduced predators may directly affect some native species via predation, which may in turn have indirect consequences for other species that are released from competition. We explore t...
Conference Paper
Full-text available
Inland fisheries represent an important source of protein and income for many communities, particularly in the tropics. It has been shown that ectotherms living in climatically stable tropical environments tend to be thermal specialists, and that some of them achieve their optimal metabolic performance at temperatures near their upper tolerance lim...
Article
Full-text available
The use of non‐lethal experiments to elucidate behavioural and physiological thresholds to environmental stressors can provide valuable data for identifying threats to, and critical habitat of, imperilled species. Increased turbidity contributes to population declines and loss of fish diversity globally, but the complex direct and indirect effects...
Article
Full-text available
African tropical lakes provide vital ecosystem services including food and water to some of the fastest growing human populations, yet they are among the most understudied ecosystems in the world. The consequences of climate change and other stressors on the tropical lakes of Africa have been informed by long-term analyses, but these studies have l...
Article
Gene flow among populations in different selective environments should favor the evolution of phenotypic plasticity over local adaptation. Plasticity in development is a common response to long-term hypoxia in some widespread African fishes, including Pseudocrenilabrus multicolor, a cichlid that exploits both normoxic (high oxygen) rivers/lakes and...
Article
Full-text available
Habitat‐associated trait divergence may vary across ontogeny if there are strong size‐related shifts in selection pressures. We quantified patterns of phenotypic divergence in Nile perch (Lates niloticus) from ecologically distinct wetland edge and forest edge habitats in Lake Nabugabo, Uganda, and we compared patterns of divergence across three si...
Article
Full-text available
Population level response to hypoxia has become an issue of global significance because of increased frequency and intensity of hypoxic events worldwide, and the potential for global warming to exacerbate hypoxic stress. In this study, we sequenced two nuclear intronic regions and a single mitochondrial region across seven populations of the Africa...
Article
Aquatic hypoxia is generally viewed as stressful for aerobic organisms. However, hypoxia may also benefit organisms by decreasing cellular stress, particularly that related to free radicals. Thus, an ideal habitat may have the minimum O2 necessary to both sustain aerobic metabolism and reduce the need to scavenge free radicals and repair free radic...
Article
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Parallel adaptive radiation events provide a powerful framework for investigations of ecology's contribution to phenotypic diversification. Ecologically driven divergence has been invoked to explain the repeated evolution of sympatric dwarf and normal lake whitefish (Coregonus clupeaformis) species in multiple lakes in eastern North America. Nevert...
Article
Wetlands in the Lake Victoria basin serve as structural and hypoxic refugia for some native fishes against predation by introduced Nile perch ( Lates niloticus ); however, little is known about the fine‐scale patterns of distribution and abundance of these refuge inhabitants. This study sought to quantify wetland ecological gradients and determine...
Article
Full-text available
Nile perch (Lates niloticus) was introduced to the Lake Victoria basin in the 1950s and 1960s and eventually became one of the most valuable commercial species of East Africa's inland fisheries. Intense fishing-induced mortality may be contributing to dramatic ecological change in this species (reductions in body size and catch rate) and reinforcin...
Article
Aquatic hypoxia can affect predator-prey interactions by altering the success rate of the predator and/or the vulnerability of prey. For example, in the Lake Victoria basin of East Africa, native prey exploit hypoxic wetlands as refugia from predation by introduced Nile perch (Lates niloticus). Here, it is predicted that species exploitation of wet...
Article
Damselfly larvae, important predators and prey in many freshwater communities, may be particularly sensitive to hypoxia because their caudal lamellae (external gills) are frequently lost. In this study, we address how lost lamellae interact with low oxygen to affect respiration and behavior of the widespread North American damselfly Ischnura posita...