scholarly journals Effects of species invasion on population dynamics, vital rates, and life histories of the native species

2017 ◽  
Author(s):  
Simone Vincenzi ◽  
Alain J Crivelli ◽  
Dusan Jesensek ◽  
Ellen Campbell ◽  
John C Garza
Keyword(s):  
Population Dynamics ◽  
Rainbow Trout ◽  
Native Species ◽  
Life Histories ◽  
Life History Theory ◽  
Individual Growth ◽  
Growth Trajectories ◽  
Natural Environments ◽  
Vital Rates ◽  
Marble Trout

AbstractInvasions occurring in natural environments provide the opportunity to study how vital rates change and life histories evolve in the presence of a competing species. In this work, we estimate differences in reproductive traits, individual growth trajectories, survival, life histories, and population dynamics between a native species living in allopatry and in sympatry with an invasive species of the same taxonomic Family. We used as a model system marble trout Salmo marmoratus (native species) and rainbow trout Oncorhynchus mykiss (non-native) living in the Idrijca River (Slovenia). An impassable waterfall separates the stream in two sectors only a few hundred meters apart: a downstream sector in which marble trout live in sympatry with rainbow trout and a upstream sector in which marble trout live in allopatry. We used an overarching modeling approach that uses tag-recapture and genetic data (> 2,500 unique marble and rainbow trout were sampled and SNP-genotyped) to reconstruct pedigrees, test for synchrony of population dynamics, and model survival and growth while accounting for individual heterogeneity in performance. The population dynamics of the two marble trout populations and of rainbow trout were overall synchronous. We found higher prevalence of younger parents, higher mortality, and lower population density in marble trout living in sympatry with rainbow trout than in marble trout living in allopatry. There were no differences in the average individual growth trajectories between the two marble trout populations. Faster life histories of marble trout living in sympatry with rainbow trout are consistent with predictions of life-history theory.

scholarly journals Within and among-population variation in vital rates and population dynamics in a variable environment

2015 ◽  
Author(s):  
Simone Vincenzi ◽  
Marc Mangel ◽  
Dusan Jesensek ◽  
John Carlos Garza ◽  
Alain J Crivelli
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
Debris Flows ◽  
Life Histories ◽  
Population Variation ◽  
Population Differences ◽  
Vital Rates ◽  
Marble Trout ◽  
Over Time

Understanding the causes of within- and among-population differences in vital rates, life histories, and population dynamics is a central topic in ecology. To understand how within- and among-population variation emerges, we need long-term studies that include episodic events and contrasting environmental conditions, data to characterize individual and shared variation, and statistical models that can tease apart population-, shared-, and individual contribution to the observed variation. We used long-term tag-recapture data and novel statistical and modeling techniques to investigate and estimate within- and among-population differences in vital rates, life histories and population dynamics of marble trout Salmo marmoratus, a endemic freshwater salmonid with a narrow range. Only ten populations of pure marble trout persist in headwaters of Alpine rivers in western Slovenia. Marble trout populations are also threatened by floods and landslides, which have caused the extinction of two populations in recent years. We estimated and determined causes of variation in growth, survival, and recruitment both within and among populations, and evaluated trade-offs between them. Specifically, we estimated the responses of these traits to variation in water temperature, density, sex, early life conditions, and the occurrence of extreme climatic events (e.g., flash floods and debris flows). We found that the effects of population density on traits were mostly limited to the early stages of life and that individual growth trajectories were established early in life. We found no clear effects of water temperature on survival and recruitment. Population density varied over time, with flash floods and debris flows causing massive mortalities and threatening population persistence. Apart from flood events, variation in population density within streams was largely determined by variation in recruitment, with survival of older fish being relatively constant over time within populations, but substantially different among populations. Marble trout show a fast to slow continuum of life histories, with slow growth associated with higher survival at the population level, possibly determined by food conditions and age at maturity. Our work provides unprecedented insight into the causes of variation in vital rates, life histories, and population dynamics in an endemic species that is teetering on the edge of extinction.

scholarly journals Effects of species invasion on population dynamics, vital rates and life histories of the native species

2018 ◽  
Vol 61 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Simone Vincenzi ◽  
Alain J. Crivelli ◽  
Dušan Jeseňsek ◽  
Ellen Campbell ◽  
John C. Garza
Keyword(s):  
Population Dynamics ◽  
Native Species ◽  
Life Histories ◽  
Vital Rates ◽  
Species Invasion

scholarly journals Estimates of vital rates and predictions of population dynamics change along a long-term monitoring program

2017 ◽  
Author(s):  
Simone Vincenzi ◽  
Dusan Jesensek ◽  
Alain J. Crivelli
Keyword(s):  
Population Dynamics ◽  
Salmo Trutta ◽  
Monitoring Program ◽  
Individual Growth ◽  
Vital Rates ◽  
Size Change ◽  
Marble Trout ◽  
Average Survival ◽  
Future Population

AbstractDespite the widespread recognition of the importance of monitoring, only a few studies have investigated how estimates of vital rates and predictions of population dynamics change with additional data collected along the monitoring program. We investigate how using the same models estimates of survival, individual growth, along with predictions about future population size change with additional years of monitoring and data collected, using as a model system freshwater populations of marble (Salmo marmoratus), rainbow (Oncorhynchus mykiss), and brown trout (Salmo trutta L.) living in Western Slovenian streams. Fish were sampled twice a year between 2004 and 2015. We found that in 3 out of 4 populations, a few years of data (3 or 4 sampling occasions, between 300 and 500 tagged individuals for survival, 100 to 200 for growth) provided the same estimates of average survival and growth as those obtained with data from more than 15 sampling occasions, while the estimation of the range of survival required more sampling occasions (up to 22 for marble trout), with little reduction of uncertainty around the point estimates. Predictions of mean density and variation in density over time did not change with more data collected after the first 5 years (i.e., 10 sampling occasions) and overall were within 10% of the observed mean and variation in density over the whole monitoring program.

scholarly journals Sympatry with the devil? Niche-based approach explains the mechanisms allowing coexistence of native and non-native salmonids

2016 ◽  
Author(s):  
Camille Musseau ◽  
Simone Vincenzi ◽  
Dušan Jesenšek ◽  
Stéphanie Boulêtreau ◽  
Frédéric Santoul ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Native Species ◽  
Niche Breadth ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Growth Period ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Niche Shift ◽  
Marble Trout

AbstractNiche-based hypotheses have been proposed to explain processes and mechanisms of success in the establishment of non-native species into native communities. Competition due to niche overlap may lead to native species niche shift and to native species replacement. To understand the ecological consequences of trophic interactions between non-native rainbow trout and native and endangered marble trout, we used as model system the Idrijca river (Western Slovenia) in which marble trout occurs either in allopatry (MTa) or in sympatry (MTs) with rainbow trout (RTs). We focused on different metrics of niche change such as centroid shift, niche overlap and trophic niche breadth using stable isotope analysis (δ15N and δ13C). Our results showed plasticity in niche overlap between MTs and RTs and niche shift of marble trout when occurring in sympatry with RTs, but not due to a niche replacement of MTs by RTs. Niche breadth of marble trout increases in sympatry and the trophic position during the growth period was higher for MTs than MTa.

scholarly journals Harsh environments and "fast" human life histories: What does the theory say?

2015 ◽  
Author(s):  
Ryan Baldini
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Theory ◽  
Environmental Changes ◽  
Human Life ◽  
Life History Evolution ◽  
Harsh Environments ◽  
Harsh Environment ◽  
Common Belief ◽  
Vital Rates

A common belief among human life history researchers is that "harsher" environments - i.e., those with higher mortality rates and resource stress - select for "fast" life histories, i.e. earlier reproduction and faster senescence. I show that these "harsh environments, fast life histories" - or HEFLH - hypotheses are poorly supported by evolutionary theory. First, I use a simple model to show that effects of environmental harshness on life history evolution are incredibly diverse. In particular, small changes in basic but poorly understood variables - e.g., whether and how population density affects vital rates - can cause selection to favor very different life histories. Furthermore, I show that almost all life history theory used to justify HEFLH hypotheses is misapplied in the first place. The reason is that HEFLH hypotheses usually treat plastic responses to heterogeneous environmental conditions within a population, whereas the theory used to justify such hypotheses treat genetic responses to environmental changes across an entire population. Counter-intuitively, the predictions of the former do not generally apply to the latter: the optimal response to a harsh environment within a large heterogeneous environment is not necessarily the optimal strategy of a population uniformly inhabiting the same harsh environment. I discuss these theoretical results in light of the current state of empirical research.

Bonobo population dynamics: Past patterns and future predictions for the Lola ya Bonobo population using demographic modelling

2018 ◽  
Author(s):  
Lisa J. Faust ◽  
Claudine André ◽  
Raphaël Belais ◽  
Fanny Minesi ◽  
Zjef Pereboom ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Pan Troglodytes ◽  
Growth Trajectories ◽  
Demographic Model ◽  
Pan African ◽  
Demographic Modelling ◽  
Projected Changes ◽  
Demographic Patterns ◽  
Future Population ◽  
Future Growth

Wildlife sanctuaries rescue, rehabilitate, reintroduce and provide life-long care for orphaned and injured animals. Understanding a sanctuary’s population dynamics—patterns in arrival, mortality and projected changes in population size—allows careful planning for future needs. Building on previous work on the population dynamics of chimpanzees (Pan troglodytes) in sanctuaries of the Pan African Sanctuary Alliance (PASA; Faust et al. 2011), this chapter extends analyses to the only PASA bonobo sanctuary. Its authors analysed historic demographic patterns and projected future population dynamics using an individual-based demographic model. The population has been growing at 6.7 per cent per year, driven by arrivals of new individuals (mean = 5.5 arrivals per year). Several model scenarios projecting varying arrival rates, releases and breeding scenarios clarify potential future growth trajectories for the sanctuary. This research illustrates how data on historic dynamics can be modelled to inform future sanctuary capacity and management needs. Les sanctuaires de faune secourent, réhabilitent, réintroduisent, et fournissent des soins pour toute la vie aux animaux orphelins et blessés. Comprendre les dynamiques de la population d’un sanctuaire—les motifs d’arrivée, mortalité, et de changements projetés de la taille de la population—permet une planification prudente pour les nécessités du futur. En se basant sur le travail déjà fait sur les dynamiques de la population chimpanzé (Pan troglodytes) dans les sanctuaires du Pan African Sanctuary Alliance (PASA; Faust et al. 2011), nous étendons notre analyse au seul sanctuaire bonobo par PASA. Nous avons analysé les motifs démographiques historiques et avons projeté les futures dynamiques de la population en utilisant un modèle démographique basé sur l’individu. La population augmente de 6.7 per cent par an, poussée par l’arrivée de nouveaux individus (moyenne = 5.5 arrivées par an). Plusieurs scénarios modèles montrent une trajectoire de potentielle croissance pour le sanctuaire. Cette recherche illustre comment modeler les données sur les dynamiques historiques pour informer la capacité future du sanctuaire et les besoins gestionnaires.

scholarly journals Demographic effects of interacting species: exploring stable coexistence under increased climatic variability in a semiarid shrub community

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana I. García-Cervigón ◽  
Pedro F. Quintana-Ascencio ◽  
Adrián Escudero ◽  
Merari E. Ferrer-Cervantes ◽  
Ana M. Sánchez ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Species Coexistence ◽  
Climatic Factors ◽  
Demographic Data ◽  
Climatic Variability ◽  
Biotic Interactions ◽  
Vital Rates ◽  
Climatic Fluctuations ◽  
Demographic Models ◽  
Shrub Community

AbstractPopulation persistence is strongly determined by climatic variability. Changes in the patterns of climatic events linked to global warming may alter population dynamics, but their effects may be strongly modulated by biotic interactions. Plant populations interact with each other in such a way that responses to climate of a single population may impact the dynamics of the whole community. In this study, we assess how climate variability affects persistence and coexistence of two dominant plant species in a semiarid shrub community on gypsum soils. We use 9 years of demographic data to parameterize demographic models and to simulate population dynamics under different climatic and ecological scenarios. We observe that populations of both coexisting species may respond to common climatic fluctuations both similarly and in idiosyncratic ways, depending on the yearly combination of climatic factors. Biotic interactions (both within and among species) modulate some of their vital rates, but their effects on population dynamics highly depend on climatic fluctuations. Our results indicate that increased levels of climatic variability may alter interspecific relationships. These alterations might potentially affect species coexistence, disrupting competitive hierarchies and ultimately leading to abrupt changes in community composition.

scholarly journals Within- and among-population variation in vital rates and population dynamics in a variable environment

2016 ◽  
Vol 26 (7) ◽  
pp. 2086-2102 ◽  
Author(s):  
Simone Vincenzi ◽  
Marc Mangel ◽  
Dusˇan Jesensˇek ◽  
John C. Garza ◽  
Alain J. Crivelli
Keyword(s):  
Population Dynamics ◽  
Population Variation ◽  
Vital Rates ◽  
Variable Environment

scholarly journals Robustness of life histories to environmental variability in complex versus simple life cycles

2021 ◽  
Author(s):  
Annie Jonsson
Keyword(s):  
Growth Rate ◽  
Life Histories ◽  
Environmental Variability ◽  
Life Cycles ◽  
Relative Advantage ◽  
Complex Life Cycle ◽  
Life Stages ◽  
Vital Rates ◽  
Habitat Separation ◽  
Simple Life

AbstractMost animal species have a complex life cycle (CLC) with metamorphosis. It is thus of interest to examine possible benefits of such life histories. The prevailing view is that CLC represents an adaptation for genetic decoupling of juvenile and adult traits, thereby allowing life stages to respond independently to different selective forces. Here I propose an additional potential advantage of CLCs that is, decreased variance in population growth rate due to habitat separation of life stages. Habitat separation of pre- and post-metamorphic stages means that the stages will experience different regimes of environmental variability. This is in contrast to species with simple life cycles (SLC) whose life stages often occupy one and the same habitat. The correlation in the fluctuations of the vital rates of life stages is therefore likely to be weaker in complex than in simple life cycles. By a theoretical framework using an analytical approach, I have (1) derived the relative advantage, in terms of long-run growth rate, of CLC over SLC phenotypes for a broad spectrum of life histories, and (2) explored which life histories that benefit most by a CLC, that is avoid correlation in vital rates between life stages. The direction and magnitude of gain depended on life history type and fluctuating vital rate. One implication of our study is that species with CLCs should, on average, be more robust to increased environmental variability caused by global warming than species with SLCs.

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