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result(s) for
"long‐term study"
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Social influences on survival and reproduction
2019
For social species, the environment has two components: physical and social. The social environment modifies the individual's interaction with the physical environment, and the physical environment may in turn impact individuals’ social relationships. This interplay can generate considerable variation among individuals in survival and reproduction. Here, I synthesize more than four decades of research on the baboons of the Amboseli basin in southern Kenya to illustrate how social and physical environments interact to affect reproduction and survival. For immature baboons, social behaviour can both mitigate and exacerbate the challenge of survival. Only c. 50% of live‐born females and c. 44% of live‐born males reach the median age of first reproduction. Variation in pre‐adult survival, growth and development is associated with multiple aspects of the social environment. For instance, conspecifics provide direct care and are a major source of social knowledge about food and the environment, but conspecifics can also represent a direct threat to survival through infanticide. In adulthood, both competition (within and between social groups) and cooperative affiliation (i.e. collective action and/or the exchange of social resources such as grooming) are prominent features of baboon social life and have important consequences for reproduction and survival. For instance, adult females with higher social dominance ranks have accelerated reproduction, and adult females that engage in more frequent affiliative social interactions have higher survival throughout adulthood. The early life environment also has important consequences for adult reproduction and survival, as in a number of other bird and mammal species. In seasonal breeders, early life effects often apply to entire cohorts; in contrast, in nonseasonal and highly social species such as baboons, early life effects are more individual‐specific, stemming from considerable variation not only in the early physical environment (even if they are born in the same year) but also in the particulars of their social environment. An animal's survival and reproduction are determined by how it interacts with its environment; for social species, this includes both the physical and the social environment. The variation in resource distribution that results from social behavior can generate considerable variation in survival and reproduction. This study synthesizes more than four decades of long‐term research on the ecology and social behavior of baboons of the Amboseli basin to describe the challenges and opportunities presented by the physical and social environments, how they unfold over the course of an animal's life, and how animals meet them. Photo credit A.C. Markham
Journal Article
A fish tale
2021
Plastic is pervasive in modern economies and ecosystems. Freshwater fish ingest microplastics (i.e., particles <5 mm), but no studies have examined historical patterns of their microplastic consumption. Measuring the patterns of microplastic pollution in the past is critical for predicting future trends and for understanding the relationship between plastics in fish and the environment. We measured microplastics in digestive tissues of specimens collected from the years 1900–2017 and preserved in museum collections. We collected new fish specimens in 2018, along with water and sediment samples. We selected four species: Micropterus salmoides (largemouth bass), Notropis stramineus (sand shiner), Ictalurus punctatus (channel catfish), and Neogobius melanostomus (round goby) because each was well represented in museum collections, are locally abundant, and collected from urban habitats. For each individual, we dissected the digestive tissue from esophagus to anus, subjected tissue to peroxide oxidation, examined particles under a dissecting microscope, and used Raman spectroscopy to characterize the particles’ chemical composition. No microplastics were detected in any fish prior to 1950. From mid-century to 2018, microplastic concentrations showed a significant increase when data from all fish were considered together. All detected particles were fibers, and represented plastic polymers (e.g., polyester) along with mixtures of natural and synthetic textiles. For the specimens collected in 2018, microplastics in fish and sediment showed similar patterns across study sites, while water column microplastics showed no differences among locations. Overall, plastic pollution in common freshwater fish species is increasing and pervasive across individuals and species, and is likely related to changes in environmental concentrations. Museum specimens are an overlooked source for assessing historical patterns of microplastic pollution, and for predicting future trends in freshwater fish, thereby helping to sustain the health of commercial and recreational fisheries worldwide.
Journal Article
Long‐term declines in insect abundance and biomass in a subalpine habitat
by
Dalton, Rebecca M.
,
Underwood, Nora C.
,
Soulé, Michael E.
in
Agricultural land
,
Anthropogenic factors
,
Biomass
2023
Recent reports of insect declines have caused concern among scientists and the public. Declines in insect abundance and biomass are ubiquitous across many climatic zones and have been largely attributed to anthropogenic land use intensification and climate change. However, there are few examples of long‐term continuous data in relatively undisturbed environments, as opposed to agricultural landscapes. We sampled insects weekly from 1986 to 2020 in a protected subalpine meadow in Colorado, which is embedded in an undisturbed natural landscape. During the study period, summers became warmer, while winters became drier. Insect biomass declined by ∼47% and abundance declined by ∼61.5% over the last 35 years. Insect declines occurred in concert with changes in climate, as some climate factors were correlated with insect abundance and biomass. Specifically, insect abundance was lower during years with less summer precipitation and winter snowfall, and to a lesser degree with warmer temperatures. In subalpine systems, changes in precipitation and warmer temperatures are expected to continue under climate change; thus, continued insect declines might be expected even in relatively undisturbed habitats.
Journal Article
Concordance of long-term shifts with climate warming varies among phenological events and herbaceous species
2020
Many temperate herbs now flower earlier than a few decades ago. Little is known about other phenological events, despite the importance of life history integration for plant fitness. This study addresses the hypothesis that temporal shifts of multiple phenological events in herbs are concordant with temporal changes in weather. Explicitly showing that changes in timing of annual life cycle events are correlated with changes in weather-predicting variables provides support for the hypothesis that a phenological shift is concordant with climate change. Observations of six phenological events and five phenophases were made year-round for 25 yr for herb species in a deciduous forest fragment, Trelease Woods in Illinois, USA. Dates for 43 species were analyzed by linear mixed-effects models for events and phenophases and were compared to weather data from a nearby station. For early species, emergence was delayed by 1.5 d/decade, while end expansion advanced by 3.8 d/decade and begin dormancy advanced by 2.5 d/decade. For late species, end expansion advanced by 6.7 d/decade, while begin senescence delayed by 17.7 d/decade. Begin flowering and end flowering advanced similarly for both seasonal groups, at 3.8 to 4.2 d/decade. Some events showed no temporal change. Species differed greatly in the degree or direction of change, related to seasonality of event or length of phase. Overall, for a given species, most events are advancing (68.4%) and most durations are shortening (74.4%). In 12 of 13 cases, inter-annual variation in event date was predicted by a temperature-event–season combination variable, but in only six cases did both event date shift and weather variable warm through time. This finding supports the hypothesis that climate change is associated with changes in some, but not all, phenological events. This first long-term, multi-phase study of a community of temperate herb species indicates little temporal coherence of responses of multiple phases. Changes in date are event specific, phase specific, and species specific. This complexity of responses among species and uneven responses within a species' integrated annual cycle events has implications for evolutionary responses and more immediate interactions among plant, animal, and microbe species in this community.
Journal Article
Wildlife disease ecology from the individual to the population: Insights from a long-term study of a naturally infected European badger population
2018
1. Long-term individual-based datasets on host-pathogen systems are a rare and valuable resource for understanding the infectious disease dynamics in wildlife. A study of European badgers (Meles meles) naturally infected with bovine tuberculosis (bTB) at Woodchester Park in Gloucestershire (UK) has produced a unique dataset, facilitating investigation of a diverse range of epidemiological and ecological questions with implications for disease management. 2. Since the 1970s, this badger population has been monitored with a systematic mark-recapture regime yielding a dataset of > 15,000 captures of >3,000 individuals, providing detailed individual life-history, morphometric, genetic, reproductive and disease data. 3. The annual prevalence of bTB in the Woodchester Park badger population exhibits no straightforward relationship with population density, and both the incidence and prevalence of Mycobacterium bovis show marked variation in space. The study has revealed phenotypic traits that are critical for understanding the social structure of badger populations along with mechanisms vital for understanding disease spread at different spatial resolutions. 4. Woodchester-based studies have provided key insights into how host ecology can influence infection at different spatial and temporal scales. Specifically, it has revealed heterogeneity in epidemiological parameters; intrinsic and extrinsic factors affecting population dynamics; provided insights into senescence and individual life histories; and revealed consistent individual variation in foraging patterns, refuge use and social interactions. 5. An improved understanding of ecological and epidemiological processes is imperative for effective disease management. Woodchester Park research has provided information of direct relevance to bTB management, and a better appreciation of the role of individual heterogeneity in disease transmission can contribute further in this regard. 6. The Woodchester Park study system now offers a rare opportunity to seek a dynamic understanding of how individual-, group- and population-level processes interact The wealth of existing data makes it possible to take a more integrative approach to examining how the consequences of individual heterogeneity scale to determine population-level pathogen dynamics and help advance our understanding of the ecological drivers of host-pathogen systems.
Journal Article
Long-term persistence of experimental populations beyond a species’ natural range
by
Cross, Regan L.
,
Eckert, Christopher G.
in
Camissoniopsis cheiranthifolia
,
Crop production
,
Density
2021
Ecological experiments usually infer long-term processes from short-term data, and the analysis of geographic range limits is a good example. Species’ geographic ranges may be limited by low fitness due to niche constraints, a hypothesis most directly tested by comparing the fitness of populations transplanted within and beyond the range. Such studies often fail to find beyond-range fitness declines strong enough to conclude that geographic range limits are solely imposed by niche limits. However, almost all studies only follow transplants for a single generation, which will underestimate the importance of niche limitation because critical but infrequent range-limiting events may be missed and methodological issues may artificially boost the fitness of beyond-range transplants. Here, we present the first multi-generation beyond-range transplant experiment that involves adequate replication and proper experimental controls. In 2005, experimental populations of the coastal dune plant Camissoniopsis cheiranthifolia were planted at four sites within and one site beyond the northern limit. Fitness of initial transplants was high beyond the limit, suggesting that the range was limited by dispersal and not niche constraints. To better address the niche-limitation hypothesis, we quantified density and fitness of descendant C. cheiranthifolia populations 12–14 yr (∼10 generations) after transplant. Average annual fruit production and density of reproductive individuals were as high beyond the range as at four comparable experimental populations and eight natural populations within the range, and the beyond-range population had more than tripled in size since it was planted. This provides unprecedented support for the conclusion that northern range limit of C. cheiranthifolia results from something other than niche limitation, likely involving constraints on local dispersal.
Journal Article
Spring temperatures influence selection on breeding date and the potential for phenological mismatch in a migratory bird
by
Grindstaff, Jennifer L.
,
Bowers, E. Keith
,
Drilling, Nancy E.
in
Animal breeding
,
Animal Migration
,
Animal reproduction
2016
Climate change has affected the seasonal phenology of a variety of taxa, including that of migratory birds and their critical food resources. However, whether climate-induced changes in breeding phenology affect individual fitness, and how these changes might therefore influence selection on breeding date remain unresolved. Here, we use a 36-yr dataset from a long-term, individual-based study of House Wrens (Troglodytes aedon) to test whether the timing of avian breeding seasons is associated with annual changes in temperature, which have increased to a small but significant extent locally since the onset of the study in 1980. Increasing temperature was associated with an advancement of breeding date in the population, as the onset of breeding within years was closely associated with daily spring temperatures. Warmer springs were also associated with a reduced incubation period, but reduced incubation periods were associated with a prolonged duration of nestling provisioning. Nest productivity, in terms of fledgling production, was not associated with temperature, but wetter springs reduced fledging success. Most years were characterized by selection for earlier breeding, but cool and wet years resulted in stabilizing selection on breeding date. Our results indicate that climate change and increasing spring temperatures can affect suites of life-history traits, including selection on breeding date. Increasing temperatures may favor earlier breeding, but the extent to which the phenology of populations might advance may be constrained by reductions in fitness associated with early breeding during cool, wet years. Variability in climatic conditions will, therefore, shape the extent to which seasonal organisms can respond to changes in their environment.
Journal Article
Climate disturbances during critical periods pose risks to European hamster conservation efforts
by
Łopucki, Rafał
,
Wójciak, Janusz
,
Klich, Daniel
in
Central European region
,
Cereals
,
Clanga pomarina
2024
Aim Long‐term population studies provide invaluable insights into natural variability, particularly in ecology and conservation. We reconstruct the 31‐year dynamics of the European hamster population in a vast area within Central Europe. We identify key meteorological factors influencing population dynamics and project the potential impact of climate change on their conservation. Location Poland. Methods As an indicator of hamster population changes, we utilized data on the prey of the Lesser Spotted Eagle (Clanga pomarina) collected over 31 years (1993–2023) in the geographical region where the European hamster coexists. The reliability of ornithological data was validated. Results Meteorological factors play a critical role in driving hamster population changes. We found a strong correlation between population growth and warm weather patterns in October and November, as well as favourable conditions in March of the following year. These weather patterns allow hamsters to store larger food supplies and enter hibernation in better physiological condition, resulting in improved habitat and nutritional conditions upon emergence from hibernation in spring. Main Conclusions Our findings underscore the importance of considering meteorological factors in conservation risk assessments, especially when planning and evaluating hamster reintroduction programmes. The significant influence of meteorological conditions raises concerns about the future prospects of this species in the context of ongoing climate change. Disturbances during critical hamster periods, including unseasonal and prolonged temperature drops in spring following relatively warm winters, pose substantial risks to conservation efforts.
Journal Article
Secondary forest succession buffers extreme temperature impacts on subtropical Asian ants
by
Fellowes, John R.
,
Guénard, Benoit
,
Morgan, Brett
in
adaptive conservation
,
beta diversity
,
Biodiversity
2021
Secondary forest succession may restore microclimatic refugia for ectotherms and play a fundamental role in mitigating the combined effects of deforestation and climate warming on biodiversity; however, empirical evidence remains limited by short-term, coarsescale, and solely taxonomic-based approaches. We hypothesize that ant assemblage composition will respond differently to an increased frequency of extreme heat events between sites with and without microclimatic refugia provided by secondary forest's regrowth. We test this hypothesis by integrating comprehensive historic surveys (1992–1994) and contemporary resampling (2015–2017) of ant assemblages to investigate how soil surface temperatures (estimated by microclimatic models [30 × 30 m]) and physical parameters (e.g., canopy cover) over the past >20 yr drive changes in their taxonomic, functional, and phylogenetic diversity for open (grasslands and shrublands) and closed (secondary forests) habitat types. Our results show a significant spatial turnover in the ant assemblage composition in both habitat types over the past two decades. Furthermore, for taxonomic, functional and phylogenetic spatial beta diversity, temperature became the primary variable explaining the differences in species composition among sites in open habitats, but not in closed habitats. Nevertheless, leaf litter cover may, to a certain extent, provide some thermal buffer for litter-dwelling species exposed to extreme heat. On the contrary, within forests, canopy cover mitigated the adverse impact of extreme heat on ant assemblages, with a shift toward smaller body size observed over time only in sites with lower canopy cover. These findings highlight the importance of restored canopy in providing thermal buffering for understory ectotherms. While tropical forest restoration represents an essential component in enhancing species resilience under climate warming, additionally we considered that the restoration of microclimatic regimes across different land use types is essential to conserve tropical biodiversity across the deforested landscape.
Journal Article
Modifying connectivity to promote state change reversal
by
Herrick, Jeffrey E.
,
Okin, Gregory S.
,
Zhang, Junzhe
in
aeolian processes
,
Alluvial soils
,
alternative states
2020
Alternative states maintained by feedbacks are notoriously difficult, if not impossible, to reverse. Although positive interactions that modify soil conditions may have the greatest potential to alter self-reinforcing feedbacks, the conditions leading to these state change reversals have not been resolved. In a 9-yr study, we modified horizontal connectivity of resources by wind or water on different geomorphic surfaces in an attempt to alter plant–soil feedbacks and shift woody-plant-dominated states back toward perennial grass dominance. Modifying connectivity resulted in an increase in litter cover regardless of the vector of transport (wind, water) followed by an increase in perennial grass cover 2 yr later. Modifying connectivity was most effective on sandy soils where wind is the dominant vector, and least effective on gravelly soils on stable surfaces with low sediment movement by water. We found that grass cover was related to precipitation in the first 5 yr of our study, and plant–soil feedbacks developed following 6 yr of modified connectivity to overwhelm effects of precipitation on sandy, wind-blown soils. These feedbacks persisted through time under variable annual rainfall. On alluvial soils, either plant–soil feedbacks developed after 7 yr that were not persistent (active soils) or did not develop (stable soils). This novel approach has application to drylands globally where desertified lands have suffered losses in ecosystem services, and to other ecosystems where connectivity-mediated feedbacks modified at fine scales can be expected to impact plant recovery and state change reversals at larger scales, in particular for wind-impacted sites.
Journal Article