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1.
BMC Prim Care ; 25(1): 129, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38658815

RESUMO

BACKGROUND: In the Netherlands, population-based cancer screening programmes (CSPs) are organized aiming at cervical, breast and colorectal cancer. For a CSP to be effective, high participation rates are essential; however, there is an alarming downward trend, including wide regional variation in screening uptake. General practitioner (GP) involvement can have a stimulating effect on screening participation. Current GP involvement is however, limited, varies between the programmes and has changed over time. Unexplored is what GPs think of their role(s) in the CSPs. The aim of this study was therefore to map the perceptions and beliefs of GPs regarding their current and future role in the Dutch CSPs. METHODS: A mixed-methods sequential explanatory study was conducted in the Leiden/The Hague area of the Netherlands, between the end of 2021 and 2022. A questionnaire was developed and distributed among 110 GPs. The aggregated results obtained from the questionnaires served as starting points for conducting semi-structured interviews, with purposefully selected GPs. With this sequential approach we aimed to further enhance the understanding of the questionnaire data, and delved into the topics that emerged from the questionnaire responses. RESULTS: In total, 46 GPs completed the online questionnaire (response rate 42%). Subsequent five semi-structured comprehensive interviews were conducted. GPs indicated that they frequently encounter the CSP in their daily practice and consider it important. They also emphasised it is important that GPs remain closely involved with the CSPs in the future. Nevertheless, GPs also repeatedly mentioned that they are not eager to take on more logistical/organizational tasks. They are however willing to empower CSPs in a positive manner. CONCLUSION: GPs were generally positive about the CSPs and their current role within these programmes. Nevertheless, several options have been proposed to improve the CSPs, especially to increase screening uptake for populations in a socioeconomically disadvantaged position. Since it is of utmost importance to screen those who are most at risk of developing the screening-specific tumours, efforts should be made to achieve this goal.


Assuntos
Atitude do Pessoal de Saúde , Detecção Precoce de Câncer , Clínicos Gerais , Papel do Médico , Humanos , Países Baixos/epidemiologia , Clínicos Gerais/psicologia , Detecção Precoce de Câncer/psicologia , Feminino , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Neoplasias Colorretais/diagnóstico , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/psicologia , Adulto , Neoplasias do Colo do Útero/diagnóstico , Programas de Rastreamento/métodos , Programas de Rastreamento/psicologia
2.
Ecol Evol ; 13(7): e10269, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37475724

RESUMO

Cost-effective use of limited conservation resources requires understanding which data most contribute to alleviating biodiversity declines. Interventions might reasonably prioritise life-cycle transitions with the greatest influence on population dynamics, yet some contributing vital rates are particularly challenging to document. This risks managers making decisions without sufficient empirical coverage of the spatiotemporal variation experienced by the species. Here, we aimed to explore whether the number of studies contributing estimates for a given life-stage transition aligns with that transition's demographic impact on population growth rate, λ. We parameterised a matrix population model using meta-analysis of vital rates for the common eider (Somateria mollissima), an increasingly threatened yet comparatively data-rich species of seaduck, for which some life stages are particularly problematic to study. Female common eiders exhibit intermittent breeding, with some established breeders skipping one or more years between breeding attempts. Our meta-analysis yielded a breeding propensity of 0.72, which we incorporated into our model with a discrete and reversible 'nonbreeder' stage (to which surviving adults transition with a probability of 0.28). The transitions between breeding and nonbreeding states had twice the influence on λ than fertility (summed matrix-element elasticities of 24% and 11%, respectively), whereas almost 15 times as many studies document components of fertility than breeding propensity (n = 103 and n = 7, respectively). The implications of such mismatches are complex because the motivations for feasible on-the-ground conservation actions may be different from what is needed to reduce uncertainty in population projections. Our workflow could form an early part of the toolkit informing future investment of finite resources, to avoid repeated disconnects between data needs and availability thwarting evidence-led conservation.

3.
BMJ Open ; 13(6): e071354, 2023 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-37355264

RESUMO

OBJECTIVES: Throughout Europe, many countries offer population-based cancer screening programmes (CSPs). In the Netherlands, two implemented CSPs are targeting people of 50 years and older, aiming at breast cancer (BC) and colorectal cancer (CRC). In order for a CSP to be (cost-)effective, high participation rates and outreach to the populations at risk are essential. People living in highly urbanised areas and big cities are known to participate less in CSPs. The aim of this study was to gain further insight into the participation patterns of a screening-eligible population of 50 years and over, living in a highly urbanised region, over a longer time period. DESIGN: A retrospective observational study. SETTING: Participation data of the regional screening organisation, linked to the cancer incidence data derived from the Netherlands Cancer Registry, concerning the city of The Hague, between 2005 and 2019. Attendance groups were defined as attenders (attending >50% of the invitations) and non-attenders (attending ≤50% of the invitations), and were mutually compared. RESULTS: The databases contained 106 377 unique individuals on the BC screening programme (SP) and 73 669 on the CRC-SP. Non-attendance at both CSPs was associated with living in a lower socioeconomic status (SES) neighbourhood and as a counter effect, also associated with a more unfavourable, relatively late-stage, tumour diagnosis. When combining the results of the two CSPs, our results imply high screening adherence over time. Women who did not participate in both CSPs were older, and more often lived in neighbourhoods with a lower SES score. CONCLUSIONS: Since low screening uptake is one of the factors that contribute to increasing inequalities in cancer survival, future outreach strategies should be focused on engaging specific non-attending subgroups.


Assuntos
Neoplasias da Mama , Neoplasias Colorretais , Humanos , Feminino , Países Baixos/epidemiologia , Detecção Precoce de Câncer , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/epidemiologia , Europa (Continente) , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/epidemiologia , Programas de Rastreamento
4.
Rapid Commun Mass Spectrom ; 37(15): e9533, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37127435

RESUMO

RATIONALE: Organisms that grow a hard carbonate shell or skeleton, such as foraminifera, corals or molluscs, incorporate trace elements into their shell during growth that reflect the environmental change and biological activity they experienced during life. These geochemical signals locked within the carbonate are archives used in proxy reconstructions to study past environments and climates, to decipher taxonomy of cryptic species and to resolve evolutionary responses to climatic changes. METHODS: Here, we use laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) as a time-resolved acquisition to quantify the elemental composition of carbonate shells and skeletons. We present the LABLASTER (Laser Ablation BLASt Through Endpoint in R) package, which imports a single time-resolved LA-ICP-MS analysis, then detects when the laser has ablated through the carbonate as a function of change in signal over time and outputs key summary statistics. We provide two examples within the package: a fossil planktic foraminifer and a tropical coral skeleton. RESULTS: We present the first R package that automates the selection of desired data during data reduction workflows. This is achieved by automating the detection of when the laser has ablated through a sample using a smoothed time series, followed by removal of off-target data points. The functions are flexible and adjust dynamically to maximise the duration of the desired geochemical target signal, making this package applicable to a wide range of heterogenous bioarchives. Visualisation tools for manual validation are also included. CONCLUSIONS: LABLASTER increases transparency and repeatability by algorithmically identifying when the laser has either ablated fully through a sample or across a mineral boundary and is thus no longer documenting a geochemical signal associated with the desired sample. LABLASTER's focus on better data targeting means more accurate extraction of biological and geochemical signals.


Assuntos
Terapia a Laser , Oligoelementos , Espectrometria de Massas/métodos , Lasers , Carbonatos
5.
R Soc Open Sci ; 10(5): 221256, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37181799

RESUMO

Evolutionary computation is a group of biologically inspired algorithms used to solve complex optimization problems. It can be split into evolutionary algorithms, which take inspiration from genetic inheritance, and swarm intelligence algorithms, that take inspiration from cultural inheritance. However, much of the modern evolutionary literature remains relatively unexplored. To understand which evolutionary mechanisms have been considered, and which have been overlooked, this paper breaks down successful bioinspired algorithms under a contemporary biological framework based on the extended evolutionary synthesis, an extension of the classical, genetics focused, modern synthesis. Although the idea of the extended evolutionary synthesis has not been fully accepted in evolutionary theory, it presents many interesting concepts that could provide benefits to evolutionary computation. The analysis shows that Darwinism and the modern synthesis have been incorporated into evolutionary computation but the extended evolutionary synthesis has been broadly ignored beyond: cultural inheritance, incorporated in the sub-set of swarm intelligence algorithms, evolvability, through covariance matrix adaptation evolution strategy (CMA-ES), and multilevel selection, through multilevel selection genetic algorithm (MLSGA). The framework shows a gap in epigenetic inheritance for evolutionary computation, despite being a key building block in modern interpretations of evolution. This leaves a diverse range of biologically inspired mechanisms as low hanging fruit that should be explored further within evolutionary computation and illustrates the potential of epigenetic based approaches through the recent benchmarks in the literature.

6.
Genetics ; 223(4)2023 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-36810660

RESUMO

Adaptive genetic diversity in crop wild relatives (CWRs) can be exploited to develop improved crops with higher yield and resilience if phylogenetic relationships between crops and their CWRs are resolved. This further allows accurate quantification of genome-wide introgression and determination of regions of the genome under selection. Using broad sampling of CWRs and whole genome sequencing, we further demonstrate the relationships among two economically valuable and morphologically diverse Brassica crop species, their CWRs, and their putative wild progenitors. Complex genetic relationships and extensive genomic introgression between CWRs and Brassica crops were revealed. Some wild Brassica oleracea populations have admixed feral origins; some domesticated taxa in both crop species are of hybrid origin, while wild Brassica rapa is genetically indistinct from turnips. The extensive genomic introgression that we reveal could result in false identification of selection signatures during domestication using traditional comparative approaches used previously; therefore, we adopted a single-population approach to study selection during domestication. We used this to explore examples of parallel phenotypic selection in the two crop groups and highlight promising candidate genes for future investigation. Our analysis defines the complex genetic relationships between Brassica crops and their diverse CWRs, revealing extensive cross-species gene flow with implications for both crop domestication and evolutionary diversification more generally.


Assuntos
Brassica rapa , Brassica , Brassica/genética , Filogenia , Domesticação , Brassica rapa/genética , Produtos Agrícolas/genética
8.
BMC Public Health ; 22(1): 1925, 2022 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-36243684

RESUMO

BACKGROUND: The Netherlands hosts, as many other European countries, three population-based cancer screening programmes (CSPs). The overall uptake among these CSPs is high, but has decreased over recent years. Especially in highly urbanized regions the uptake rates tend to fall below the minimal effective rate of 70% set by the World Health Organization. Understanding the reasons underlying the decision of citizens to partake in a CPS are essential in order to optimize the current screening participation rates. The aim of this study was to explore the various perspectives concerning cancer screening among inhabitants of The Hague, a highly urbanized region of the Netherlands. METHODS: A Q-methodology study was conducted to provide insight in the prevailing perspectives on partaking in CSPs. All respondents were inhabitants of the city of The Hague, the Netherlands. In an online application they ranked a set of 31 statements, based on the current available literature and clustered by the Integrated Change model, into a 9-column forced ranking grid according to level of agreement, followed by a short survey. Respondents were asked to participate in a subsequent interview to explain their ranking. By-person factor analysis was used to identify distinct perspectives, which were interpreted using data from the rankings and interviews. RESULTS: Three distinct perspectives were identified: 1). "Positive about participation", 2). "Thoughtful about participation", and 3). "Fear drives participation". These perspectives provide insight into how potential respondents, living in an urbanized region in the Netherlands, decide upon partaking in CSPs. CONCLUSIONS: Since CSPs will only be effective when participation rates are sufficiently high, it is essential to have insight into the different perspectives among potential respondents concerning partaking in a CSP. This study adds new insights concerning these perspectives and suggests several ideas for future optimization of the CSPs.


Assuntos
Detecção Precoce de Câncer , Neoplasias , Humanos , Programas de Rastreamento , Neoplasias/diagnóstico , Neoplasias/prevenção & controle , Países Baixos , Inquéritos e Questionários
10.
Int J Womens Health ; 13: 549-556, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34135643

RESUMO

BACKGROUND: Many countries organize population-based cervical cancer screening programs (CSP). In the Netherlands, eligible women are invited by mail. Marginalized women living in unstable conditions and homeless women often fail to receive the invitation letter. These women also experience access barriers to regular healthcare. Consequently, despite presumably being at higher risk of developing cervical cancer due to prevalent risk factors, marginalized women are rarely screened for cervical cancer. The aim of the study was to identify the prevalence of (pre)cancerous abnormalities among marginalized women, and subsequently explore invitation approaches to enhance their screening participation. METHODS: A cross-sectional intervention study was conducted in Rotterdam, the Netherlands. Between February and May 2019, marginalized women aged 20-60 years were invited to participate in cervical screening. A participant was considered screen-positive when they tested positive for high-risk human papilloma virus (HR-HPV) and showed cytological abnormalities. Data of the study population were compared with regional data of the Dutch CSP. Various invitation approaches were used to recruit women. RESULTS: Out of 74 included women, 12 participants (16%) were found screen-positive, against 3.4% in women screened by the Dutch CSP. The prevalence ratio for the study population was 4.4 (95% CI 1.9-8.6) compared with women screened by the Dutch CSP. Using a direct, pro-active approach resulted in participation of 92% of the included women. CONCLUSION: Marginalized women have an increased risk of (pre)cancerous cervical abnormalities in screening, compared with women screened by the Dutch CSP. A direct pro-active approach was the most effective to stimulate screening participation. Enhancement of screening uptake for this population needs special effort.

11.
Acta Chir Belg ; 121(5): 351-353, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32019461

RESUMO

Cutaneous angiosarcoma (cAS) is a rare and aggressive malignant vascular tumor, which mostly occurs in the head and neck region. The outcome of cAS is poor and timely diagnosis is paramount, but often delayed because of the slow onset and the variance in presentation. This paper reports on a case of an 88-year old woman who presented with a persisting "hematoma" in the left retro-auricular region. Although considered at initial differential diagnosis, no signs of malignancy were identified in histopathology and imaging in the diagnostic work-up. At first, short-term follow-up showed no progression of the lesion. But 3 months after the first presentation additional biopsies were taken, because of rapid expansion of the lesion. The initial histopathological findings were most consistent with a benign vascular lesion, with signs of hemorrhage and reactive inflammation. However, the additional immunohistochemical analysis showed the presence of MYC oncoprotein, which confirmed the clinical suspicion of angiosarcoma. Because size and location of the lesion rendered complete resection unattainable, radiotherapy was commenced, but no significant volume reduction could be achieved. Therefore, palliative irradiation was initiated. The patient passed away 1 month later. Clinical diagnosis is often difficult and little is known about imaging of cAS. Histology and immunohistochemistry can be misleading, as cAS are easily mistaken for other lesions. Most studies report that multimodality treatment with surgery and radiotherapy is preferable, but this can be challenging in the head & neck region.


Assuntos
Hemangiossarcoma , Neoplasias Cutâneas , Idoso de 80 Anos ou mais , Biópsia , Diagnóstico Diferencial , Feminino , Hemangiossarcoma/diagnóstico , Hemangiossarcoma/terapia , Humanos , Imuno-Histoquímica , Neoplasias Cutâneas/diagnóstico
12.
Ecol Evol ; 10(20): 11579-11590, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33144985

RESUMO

The size structure of plankton communities is an important determinant of their functions in marine ecosystems. However, few studies have quantified how organism size varies within species across biogeographical scales. Here, we investigate how planktonic foraminifera, a ubiquitous zooplankton group, vary in size across the tropical and subtropical oceans of the world. Using a recently digitized museum collection, we measured shell area of 3,799 individuals of nine extant species in 53 seafloor sediments. We first analyzed potential size biases in the collection. Then, for each site, we obtained corresponding local values of mean annual sea-surface temperature (SST), net primary productivity (NPP), and relative abundance of each species. Given former studies, we expected species to reach largest shell sizes under optimal environmental conditions. In contrast, we observe that species differ in how much their size variation is explained by SST, NPP, and/or relative abundance. While some species have predictable size variation given these variables (Trilobatus sacculifer, Globigerinoides conglobatus, Globigerinella siphonifera, Pulleniatina obliquiloculata, Globorotalia truncatulinoides), other species show no relationships between size and the studied covariates (Globigerinoides ruber, Neogloboquadrina dutertrei, Globorotalia menardii, Globoconella inflata). By incorporating intraspecific variation and sampling broader geographical ranges compared to previous studies, we conclude that shell size variation in planktonic foraminifera species cannot be consistently predicted by the environment. Our results caution against the general use of size as a proxy for planktonic foraminifera environmental optima. More generally, our work highlights the utility of natural history collections and the importance of studying intraspecific variation when interpreting macroecological patterns.

13.
Proc Natl Acad Sci U S A ; 117(49): 30980-30987, 2020 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-33229561

RESUMO

Sea-level rise resulting from the instability of polar continental ice sheets represents a major socioeconomic hazard arising from anthropogenic warming, but the response of the largest component of Earth's cryosphere, the East Antarctic Ice Sheet (EAIS), to global warming is poorly understood. Here we present a detailed record of North Atlantic deep-ocean temperature, global sea-level, and ice-volume change for ∼2.75 to 2.4 Ma ago, when atmospheric partial pressure of carbon dioxide (pCO2) ranged from present-day (>400 parts per million volume, ppmv) to preindustrial (<280 ppmv) values. Our data reveal clear glacial-interglacial cycles in global ice volume and sea level largely driven by the growth and decay of ice sheets in the Northern Hemisphere. Yet, sea-level values during Marine Isotope Stage (MIS) 101 (∼2.55 Ma) also signal substantial melting of the EAIS, and peak sea levels during MIS G7 (∼2.75 Ma) and, perhaps, MIS G1 (∼2.63 Ma) are also suggestive of EAIS instability. During the succeeding glacial-interglacial cycles (MIS 100 to 95), sea levels were distinctly lower than before, strongly suggesting a link between greater stability of the EAIS and increased land-ice volumes in the Northern Hemisphere. We propose that lower sea levels driven by ice-sheet growth in the Northern Hemisphere decreased EAIS susceptibility to ocean melting. Our findings have implications for future EAIS vulnerability to a rapidly warming world.

14.
Nat Ecol Evol ; 3(8): 1217-1224, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31285573

RESUMO

Animals exhibit an extraordinary diversity of life history strategies. These realized combinations of survival, development and reproduction are predicted to be constrained by physiological limitations and by trade-offs in resource allocation. However, our understanding of these patterns is restricted to a few taxonomic groups. Using demographic data from 121 species, ranging from humans to sponges, we test whether such trade-offs universally shape animal life history strategies. We show that, after accounting for body mass and phylogenetic relatedness, 71% of the variation in animal life history strategies can be explained by life history traits associated with the fast-slow continuum (pace of life) and with a second axis defined by the distribution of age-specific mortality hazards and the spread of reproduction. While we found that life history strategies are associated with metabolic rate and ecological modes of life, surprisingly similar life history strategies can be found across the phylogenetic and physiological diversity of animals.


Assuntos
Características de História de Vida , Reprodução , Animais , Filogenia
15.
Proc Biol Sci ; 285(1883)2018 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-30051846

RESUMO

Changes in biodiversity at all levels from molecules to ecosystems are often linked to climate change, which is widely represented univariately by temperature. A global environmental driving mechanism of biodiversity dynamics is thus implied by the strong correlation between temperature proxies and diversity patterns in a wide variety of fauna and flora. Yet climate consists of many interacting variables. Species probably respond to the entire climate system as opposed to its individual facets. Here, we examine ecological and morphological traits of 12 633 individuals of two species of planktonic foraminifera with similar ecologies but contrasting evolutionary outcomes. Our results show that morphological and ecological changes are correlated to the interactions between multiple environmental factors. Models including interactions between climate variables explain at least twice as much variation in size, shape and abundance changes as models assuming that climate parameters operate independently. No dominant climatic driver can be identified: temperature alone explains remarkably little variation through our highly resolved temporal sequences, implying that a multivariate approach is required to understand evolutionary response to abiotic forcing. Our results caution against the use of a 'silver bullet' environmental parameter to represent global climate while studying evolutionary responses to abiotic change, and show that more comprehensive reconstruction of palaeobiological dynamics requires multiple biotic and abiotic dimensions.


Assuntos
Evolução Biológica , Mudança Climática , Foraminíferos/citologia , Foraminíferos/fisiologia , Características de História de Vida , Animais , Temperatura , Zooplâncton/citologia , Zooplâncton/fisiologia
16.
Nat Commun ; 8(1): 1106, 2017 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-29062052

RESUMO

Closely related taxa are, on average, more similar in terms of their physiology, morphology and ecology than distantly related ones. How this biological similarity affects geochemical signals, and their interpretations, has yet to be tested in an explicitly evolutionary framework. Here we compile and analyze planktonic foraminiferal size-specific stable carbon and oxygen isotope values (δ13C and δ18O, respectively) spanning the last 107 million years. After controlling for dominant drivers of size-δ13C and size-δ18O trends, such as geological preservation, presence of algal photosymbionts, and global environmental changes, we identify that shared evolutionary history has shaped the evolution of species-specific vital effects in δ13C, but not in δ18O. Our results lay the groundwork for using a phylogenetic approach to correct species δ13C vital effects through time, thereby reducing systematic biases in interpretations of long-term δ13C records-a key measure of holistic organismal biology and of the global carbon cycle.


Assuntos
Evolução Biológica , Isótopos de Carbono/análise , Foraminíferos/genética , Isótopos de Oxigênio/análise , Isótopos de Carbono/metabolismo , Ecologia , Foraminíferos/química , Foraminíferos/classificação , Foraminíferos/metabolismo , Isótopos de Oxigênio/metabolismo , Plâncton/química , Plâncton/classificação , Plâncton/genética , Plâncton/metabolismo , Especificidade da Espécie
17.
Am Nat ; 190(3): 350-362, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28829645

RESUMO

The influence of within-species variation and covariation on evolutionary patterns is well established for generational and macroevolutionary processes, most prominently through genetic lines of least resistance. However, it is not known whether intraspecific phenotypic variation also directs microevolutionary trajectories into the long term when a species is subject to varying environmental conditions. Here we present a continuous, high-resolution bivariate record of size and shape changes among 12,633 individual planktonic foraminifera of a surviving and an extinct-going species over 500,000 years. Our study interval spans the late Pliocene to earliest Pleistocene intensification of northern hemisphere glaciation, an interval of profound climate upheaval that can be divided into three phases of increasing glacial intensity. Within each of these three Plio-Pleistocene climate phases, the within-population allometries predict evolutionary change from one time step to the next and that the within-phase among-population (i.e., evolutionary) allometries match their corresponding static (within-population) allometries. However, the evolutionary allometry across the three climate phases deviates significantly from the static and phase-specific evolutionary allometries in the extinct-going species. Although intraspecific variation leaves a clear signature on mean evolutionary change from one time step to the next, our study suggests that the link between intraspecific variation and longer-term micro- and macroevolutionary phenomena is prone to environmental perturbation that can overcome constraints induced by within-species trait covariation.


Assuntos
Evolução Biológica , Meio Ambiente , Fenótipo , Animais , Clima
18.
Nat Ecol Evol ; 1(2): 29, 2017 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-28812611

RESUMO

One of the best-supported patterns in life history evolution is that organisms cope with environmental fluctuations by buffering their most important vital rates against them. This demographic buffering hypothesis is evidenced by a tendency for temporal variation in rates of survival and reproduction to correlate negatively with their contribution to fitness. Here, we show that widespread evidence for demographic buffering can be artefactual, resulting from natural relationships between the mean and variance of vital rates. Following statistical scaling, we find no significant tendency for plant life histories to be buffered demographically. Instead, some species are buffered, whereas others have labile life histories with higher temporal variation in their more important vital rates. We find phylogenetic signal in the strength and direction of variance-importance correlations, suggesting that clades of plants are prone to being either buffered or labile. Species with simple life histories are more likely to be demographically labile. Our results suggest important evolutionary nuances in how species deal with environmental fluctuations.

19.
Ecology ; 98(9): 2456-2467, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28646625

RESUMO

Recent studies suggest that evolutionary changes can occur on a contemporary time scale. Hence, evolution can influence ecology and vice-versa. To understand the importance of eco-evolutionary dynamics in population dynamics, we must quantify the relative contribution of ecological and evolutionary changes to population growth and other ecological processes. To date, however, most eco-evolutionary dynamics studies have not partitioned the relative contribution of plastic and evolutionary changes in traits on population, community, and ecosystem processes. Here, we quantify the effects of heritable and non-heritable changes in body mass distribution on survival, recruitment, and population growth in wild bighorn sheep (Ovis canadensis) and compare their importance to the effects of changes in age structure, population density, and weather. We applied a combination of a pedigree-based quantitative genetics model, statistical analyses of demography, and a new statistical decomposition technique, the Geber method, to a long-term data set of bighorn sheep on Ram Mountain (Canada), monitored individually from 1975 to 2012. We show three main results: (1) The relative importance of heritable change in mass, non-heritable change in mass, age structure, density, and climate on population growth rate changed substantially over time. (2) An increase in body mass was accompanied by an increase in population growth through higher survival and recruitment rate. (3) Over the entire study period, changes in the body mass distribution of ewes, mostly through non-heritable changes, affected population growth to a similar extent as changes in age structure or in density. The importance of evolutionary changes was small compared to that of other drivers of changes in population growth but increased with time as evolutionary changes accumulated. Evolutionary changes became increasingly important for population growth as the length of the study period considered increased. Our results highlight the complex ways in which ecological and evolutionary changes can affect population dynamics and illustrate the large potential effect of trait changes on population processes.


Assuntos
Evolução Biológica , Herbivoria , Animais , Canadá , Ecossistema , Feminino , Dinâmica Populacional
20.
Ecol Evol ; 6(17): 6354-65, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27656279

RESUMO

Herbivores are major drivers of ecosystem structure, diversity, and function. Resilient ecosystems therefore require viable herbivore populations in a sustainable balance with environmental resource availability. This balance is becoming harder to achieve, with increasingly threatened species reliant on small protected areas in increasingly harsh and unpredictable environments. Arid environments in North Africa exemplify this situation, featuring a biologically distinct species assemblage exposed to extreme and volatile conditions, including habitat loss and climate change-associated threats. Here, we implement an integrated likelihood approach to relate scimitar-horned oryx (Oryx dammah) and dorcas gazelle (Gazella dorcas) density, via dung distance sampling, to habitat, predator, and geographic correlates in Dghoumes National Park, Tunisia. We show how two threatened sympatric ungulates partition resources on the habitat axis, exhibiting nonuniform responses to the same vegetation gradient. Scimitar-horned oryx were positively associated with plant species richness, selecting for vegetated ephemeral watercourses (wadis) dominated by herbaceous cover. Conversely, dorcas gazelle were negatively associated with vegetation density (herbaceous height, litter cover, and herbaceous cover), selecting instead for rocky plains with sparse vegetation. We suggest that adequate plant species richness should be a prerequisite for areas proposed for future ungulate reintroductions in arid and semi-arid environments. This evidence will inform adaptive management of reintroduced ungulates in protected environments, helping managers and planners design sustainable ecosystems and effective conservation programs.

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