scholarly journals Hydrologic filtering of fish life history strategies across the United States: implications for stream flow alteration

2015 ◽  
Vol 25 (1) ◽  
pp. 243-263 ◽  
Author(s):  
Ryan A. McManamay ◽  
Emmanuel A. Frimpong

<em>Abstract</em>.—The flow regime is considered the primary driver of physical processes in riverine ecosystems; thus we expect that the trait composition of fish assemblages might respond similarly to hydrologic variability, even at broad spatial scales. Here, we test the hypothesis that freshwater fish life history strategies on two continents (southern United States and eastern Australia) converge along gradients of hydrologic variability and primary productivity at the drainage scale. Our results show that the fishes of the United States and Australia conform to the three-dimensional adaptive space arising from the trade-offs among three basic demographic parameters of survival, fecundity, and onset and duration of reproductive life. Species from both continents represent the endpoints in adaptive space defining the periodic (19% versus 33% for the United States and Australia, respectively), opportunistic (69% versus 52%), and equilibrium life history strategies (12% versus 15%). We found evidence that fish life history composition of drainage basins in the two continents have converged across similar gradients of hydrologic variability and productivity despite phylogenetic and historical differences. Moreover, these relationships were largely consistent with predictions from life history theory. Increasing hydrologic variability has promoted the greater prevalence of opportunistic strategists (a strategy that should maximize fitness in environmental settings dominated by unpredictable environmental change) while concurrently minimizing the persistence of periodic-type species (a strategy typically inhabits seasonal, periodically suitable environments). Our study provides a conceptual framework of management options for species in regulated rivers because life history strategies are the underlying determinants for population responses to environmental change and therefore can be used to classify typical population responses to flow alteration or mitigation via environmental flow prescriptions.


2015 ◽  
Vol 113 (2) ◽  
pp. 310-315 ◽  
Author(s):  
Keelah E. G. Williams ◽  
Oliver Sng ◽  
Steven L. Neuberg

Why do race stereotypes take the forms they do? Life history theory posits that features of the ecology shape individuals’ behavior. Harsh and unpredictable (“desperate”) ecologies induce fast strategy behaviors such as impulsivity, whereas resource-sufficient and predictable (“hopeful”) ecologies induce slow strategy behaviors such as future focus. We suggest that individuals possess a lay understanding of ecology’s influence on behavior, resulting in ecology-driven stereotypes. Importantly, because race is confounded with ecology in the United States, we propose that Americans’ stereotypes about racial groups actually reflect stereotypes about these groups’ presumed home ecologies. Study 1 demonstrates that individuals hold ecology stereotypes, stereotyping people from desperate ecologies as possessing faster life history strategies than people from hopeful ecologies. Studies 2–4 rule out alternative explanations for those findings. Study 5, which independently manipulates race and ecology information, demonstrates that when provided with information about a person’s race (but not ecology), individuals’ inferences about blacks track stereotypes of people from desperate ecologies, and individuals’ inferences about whites track stereotypes of people from hopeful ecologies. However, when provided with information about both the race and ecology of others, individuals’ inferences reflect the targets’ ecology rather than their race: black and white targets from desperate ecologies are stereotyped as equally fast life history strategists, whereas black and white targets from hopeful ecologies are stereotyped as equally slow life history strategists. These findings suggest that the content of several predominant race stereotypes may not reflect race, per se, but rather inferences about how one’s ecology influences behavior.


1892 ◽  
Vol 24 (11) ◽  
pp. 270-273
Author(s):  
E. W. Doran

Although this is a common insect in many parts of the United States, it is not generally found in great numbers in any locality, and, notwith standing its general distribution, the various staes of the insect seem not to have been describe or figured.While I am not yet able to clear up all the points in its history, I have studied the insect in all its stages, though I have not reared it from the egg to maturity, on account of the time required for it to develop—in all probability three years.


2019 ◽  
Vol 20 (1) ◽  
pp. 3-21
Author(s):  
Johanna Söderström

The article argues for the utility of life diagrams as a methodological and analytical tool across various life history projects. Using research on post-war political mobilization among former combatants (in Colombia, Namibia and the United States), the article demonstrates how a life diagram can modify the interview and become a useful analytical tool. During the interview the diagram helps both the research participant and the interviewer to compare different events, weigh various experiences, and ensure that all periods of the life are covered even if the interview is not done chronologically. During the analysis, the diagram offers a contrast with the transcript of the interview, and the shape of the life diagram can be compared across interviews in search of similar types. This visual turn can help address issues of empowerment, through promoting the research participants’ own interpretation of their lives.


1962 ◽  
Vol 94 (10) ◽  
pp. 1103-1107 ◽  
Author(s):  
C. E. Brown

The Bruce spanworrn, Operophtera bruceata (Hulst), is most common in the mid latitudes of the North American Continent; in Canada it occurs from Newfoundland to the interior of British Columbia (Prentice, In Press) and has been reported from Vermont and Wisconsin in the United States (Craighead, 1950.) Three outbreaks of this insect have been recorded in Alberta. The first occurred in 1903 (de Gryse, 1925) and was apparently of short duration. The second reported by Wolley Dod (1913) occurred in 1913 and denuded hundreds of acres of aspen poplar. Heavy defoliation in the third outbreak became evident in 1957 (Brown, 1957) but an examination of Forest Insect Survey records revealed that population buildup began about 1951. The outbreak continued to expand until 1958 and began to decline in 1959; by 1961 populations were again low except for one or two isolated areas where moderate to low populations persisted. At the peak of the outbreak in 1958 approximately 50,000 square miies were moderately or heavily infested and many more lightly infested.


2017 ◽  
Vol 12 (3) ◽  
pp. 293-314 ◽  
Author(s):  
Katie Dingeman ◽  
Yekaterina Arzhayev ◽  
Cristy Ayala ◽  
Erika Bermudez ◽  
Lauren Padama ◽  
...  

The United States deported 24,870 women in 2013, mostly to Latin America. We examine life history interviews with Mexican and Central American women who were apprehended, detained, and experienced different outcomes. We find that norms of the “crimmigration era” override humanitarian concerns, such that the state treats migrants as criminals first and as persons with claims for relief second. Removal and relief decisions appear less dependent on eligibility than geography, access to legal aid, and public support. Women’s experiences parallel men’s but are often worsened by their gendered statuses. Far from passively accepting the violence of crimmigration, women resist through discourse and activism.


2012 ◽  
Vol 144 (1) ◽  
pp. 93-107 ◽  
Author(s):  
Jan Ševčík ◽  
Jostein Kjærandsen ◽  
Stephen A. Marshall

AbstractThe cave-living and monobasic fungus gnat genusSpeoleptaEdwards is reviewed with a description of the first Nearctic species,Speolepta vockerothisp. nov., from Canada (caves in Ontario and British Columbia) and the United States (Alaska). Its morphology, life history, and biology are documented and compared with the single European speciesSpeolepta leptogaster(Winnertz). A further new species,Speolepta orientalissp.nov., is described based on a single male from northern Vietnam, representing the first record of this genus from the Oriental Region.


1870 ◽  
Vol 2 (4) ◽  
pp. 43-44
Author(s):  
V. T. Chambers

Seeing in the last number of the Canadian Entomologist, a description of the egss of A. Luna, reminds me to ask of you the explanation of a curious circumstance in the life-history of one bred by me from the larva last year. I will premise that I am writing without my notes, and therefore cannot give figures accurately, but can give the facts. There may be nothing very strange about it, but two of the best entomologists in the United States inform me that it is entirely new to them. It is this:–Some time in the latter part of the summer of 1868 I took, feeding on walnut leaves, a mature larva of A. Luna; from which I did not houi to rear the mature insect, because I counted on the larva over twenty eggs like those of a Tachina, Underneath some of the eggs I could discern with a lens a minute opening through which the fly-larva had entered the body of the Luna larva. The skin of the latter was more or less discoloured under each egg, but under some-under many in fact there was a dense black spot, sometimes two lines in diameter.


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