scholarly journals Shift towards Opportunistic Life-History of Sleeper in Response to Population Decline over Multi-Decadal Overfishing

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2582
Author(s):  
Miao Xiang ◽  
Andrew L. Rypel ◽  
Fei Cheng ◽  
Jiao Qin ◽  
Lei Zhang ◽  
...  

Understanding long-term changes in life-history traits is central to assessing and managing freshwater fisheries. In this study, we explored how life-history traits have shifted in association with long-term change in population status for a native fish species (freshwater sleeper, Odontobutis sinensis, a by-catch species of shrimp traps) in the middle Yangtze lakes, China. We assessed the life-history traits of the species from Honghu Lake in 2016, where abundance had been dramatically lower following about 60 years of high fishing pressure, and made comparisons to similar data from Liangzi Lake (1957), when fishing intensity was low and abundance was high, and Bao’an Lake (1993–1994), when about 10 years of intense exploitation had occurred and abundance had greatly declined. Modern Honghu Lake sleeper exhibit life-history traits that are substantially more opportunistic compared to both of the historical populations. Modern fish were larger at age-1 and had significantly faster growth rates, a higher prevalence of sexually mature individuals and increased fecundities. Fish from the historical samples were larger and had higher age class diversity and delayed sexual maturation. Combined, the data suggest that faster growth towards early sexual maturation and reduced body sizes are associated with destabilized populations and ecosystems. Similar life-history patterns are common in other declined fish populations under exploitation. Recovering historic fish life-history dynamics requires conservation management policies aimed at reducing harvest and improving floodplain habitats.

Oecologia ◽  
2008 ◽  
Vol 159 (2) ◽  
pp. 463-472 ◽  
Author(s):  
Teddy Albert Wilkin ◽  
Andrew G. Gosler ◽  
Dany Garant ◽  
S. James Reynolds ◽  
Ben C. Sheldon

2007 ◽  
Vol 13 ◽  
pp. 333-336
Author(s):  
S.A. Härri ◽  
J. Krauss ◽  
C.B. Müller

Plant-endophyte associations can have major impacts on the dynamics of consumer interaction-webs but long-term effects of mycotoxins and the ability of herbivores to adapt to these toxins have not been studied. To understand the potential of aphids to cope with mycotoxins, we compared the life-history parameters for aphids conditioned for several generations on endophyte-infected plants with those of endophyte-naïve aphids on both endophyteinfected and endophyte-free grasses. Aphids conditioned on endophyte-infected plants produced more offspring during the first days of adulthood than endophyte-naïve aphids independent of the endophyte infection of the test environment. However, the endophyte-conditioned aphids tended to have a shorter lifespan, which resulted in similar numbers of total offspring produced for endophyte-conditioned and endophyte-naïve aphids. The difference in life-history parameters caused by the conditioning environment suggests that the effects of endophytes on herbivore life-history traits may represent an adaptive change that should be considered in future studies of endophyte-herbivore interactions. Keywords: Rhopalosiphum padi, Neotyphodium lolii, Lolium perenne, common strain, adaptation, long-term effects, microbes, endosymbionts, reproductive strategy, life-history traits


2021 ◽  
Vol 376 (1823) ◽  
pp. 20190745
Author(s):  
Svenja B. Kroeger ◽  
Daniel T. Blumstein ◽  
Julien G. A. Martin

Studies in natural populations are essential to understand the evolutionary ecology of senescence and terminal allocation. While there are an increasing number of studies investigating late-life variation in different life-history traits of wild populations, little is known about these patterns in social behaviour. We used long-term individual based data on yellow-bellied marmots (Marmota flaviventer) to quantify how affiliative social behaviours and different life-history traits vary with age and in the last year of life, and how patterns compare between the two. We found that some social behaviours and all life-history traits varied with age, whereas terminal last year of life effects were only observed in life-history traits. Our results imply that affiliative social behaviours do not act as a mechanism to adjust allocation among traits when close to death, and highlight the importance of adopting an integrative approach, studying late-life variation and senescence across multiple different traits, to allow the identification of potential trade-offs.This article is part of the theme issue ‘Ageing and sociality: why, when and how does sociality change ageing patterns?’


Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 839
Author(s):  
Becky K. Kerns ◽  
Michelle A. Day ◽  
Dana Ikeda

Conifer removal in interior woodland ecosystems of the western US is a common management treatment used to decrease fire hazard and shift woodlands to more historical states. Woody material is frequently removed by skidding material off site and via slash pile burning. Assessing the long-term outcomes of seeding treatments after such ground disturbing activities is critical for informing future management and treatment strategies. Using two designed experiments from a central Oregon juniper woodland, we resampled slash piles and skid trails 8 years after seeding. Our objectives were to assess the long-term vegetation response to conifer removal, ground disturbance, and seeding source (cultivar and local) in slash piles and skid trails. We found that seeded species persisted in the long term, but abundance patterns depended on the species, seed source, and the type of disturbance. In general, there were more robust patterns of persistence after pile burning compared to skid trails. Seeding also suppressed exotic grass cover in the long term, particularly for the local seed source. However, the invasion levels we report are still problematic and may have impacts on biodiversity, forage and fire behavior. Our short-term results were not predictive of longer-term outcomes, but short- and long-term patterns were somewhat predictable based on species life history traits and ecological succession. The use of a mix of species with different life history traits may contribute to seeding success in terms of exotic grass suppression. Lastly, our results suggest that locally adapted seed sources may perform as well or better compared to cultivars. However, more aggressive weed treatments before and after conifer removal activities and wider seeding application may be needed to effectively treat exotic grass populations.


2016 ◽  
Vol 172 ◽  
pp. 56-66 ◽  
Author(s):  
Ilaria Bernabò ◽  
Antonello Guardia ◽  
Rachele Macirella ◽  
Settimio Sesti ◽  
Antonio Crescente ◽  
...  

2021 ◽  
Author(s):  
Sébastien Lion ◽  
Sylvain Gandon

AbstractWhat is the influence of periodic environmental fluctuations on life-history evolution? We present a general theoretical framework to understand and predict the long-term evolution of life-history traits under a broad range of ecological scenarios. Indeed, this analysis yields time-varying selection gradients that help dissect the influence of the fluctuations of the environment on the competitive ability of a specific life-history mutation. We use this framework to analyse the evolution of key life-history traits of pathogens, such as transmission and virulence. These examples reveal how periodic fluctuations of the environment can affect the evolution of pathogens, and illustrate the usefulness and broad applicability of this new approach.


Diversity ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 598
Author(s):  
Carla L. Atkinson ◽  
Daniel D. Knapp ◽  
Lora L. Smith

Seasonally inundated wetlands contribute to biodiversity support and ecosystem function at the landscape scale. These temporally dynamic ecosystems contain unique assemblages of animals adapted to cyclically wet–dry habitats. As a result of the high variation in environmental conditions, wetlands serve as hotspots for animal movement and potentially hotspots of biogeochemical activity and migratory transport of nutrient subsidies. Most amphibians are semi-aquatic and migrate between isolated wetlands and the surrounding terrestrial system to complete their life cycle, with rainfall and other environmental factors affecting the timing and magnitude of wetland export of juveniles. Here we used a long-term drift fence study coupled with system-specific nutrient content data of amphibians from two small wetlands in southeastern Georgia, USA. We couple environmental data with count data of juveniles exiting wetlands to explore the controls of amphibian diversity, production and export and the amphibian life-history traits associated with export over varying environmental conditions. Our results highlight the high degree of spatial and temporal variability in amphibian flux with hydroperiod length and temperature driving community composition and overall biomass and nutrient fluxes. Additionally, specific life-history traits, such as development time and body size, were associated with longer hydroperiods. Our findings underscore the key role of small, isolated wetlands and their hydroperiod characteristics in maintaining amphibian productivity and community dynamics.


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