pinecone/core-2020-05-10-deduplication huggingface dataset:
Long-term continental changes in wing length, but not bill length, of a long-distance migratory shorebird

Citation: Lank, D. B., Xu, C., Harrington, B. A., Morrison, R. I. G., Gratto-Trevor, C. L., Hicklin, P. W., . . . Ydenberg, R. C. (2017). Long-term continental changes in wing length, but not bill length, of a long-distance migratory shorebird. Ecology and Evolution, 7(9), 3243-3256. doi:10.1002/ece3.2898We compiled a >50-year record of morphometrics for semipalmated sandpipers (Calidris pusilla), a shorebird species with a Nearctic breeding distribution and intercontinental migration to South America. Our data included >57,000 individuals captured 1972–2015 at five breeding locations and three major stopover sites, plus 139 museum specimens collected in earlier decades. Wing length increased by ca. 1.5 mm (>1%) prior to 1980, followed by a decrease of 3.85 mm (nearly 4%) over the subsequent 35 years. This can account for previously reported changes in metrics at a migratory stopover site from 1985 to 2006. Wing length decreased at a rate of 1,098 darwins, or 0.176 haldanes, within the ranges of other field studies of phenotypic change. Bill length, in contrast, showed no consistent change over the full period of our study. Decreased body size as a universal response of animal populations to climate warming, and several other potential mechanisms, are unable to account for the increasing and decreasing wing length pattern observed. We propose that the post-WWII near-extirpation of falcon populations and their post-1973 recovery driven by the widespread use and subsequent limitation on DDT in North America selected initially for greater flight efficiency and latterly for greater agility. This predation danger hypothesis accounts for many features of the morphometric data and deserves further investigation in this and other species. © 2017 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd
Food availability as a major driver in the evolution of life-history strategies of sibling species.

Life-history theory predicts trade-offs between reproductive and survival traits such that different strategies or environmental constraints may yield comparable lifetime reproductive success among conspecifics. Food availability is one of the most important environmental factors shaping developmental processes. It notably affects key life-history components such as reproduction and survival prospect. We investigated whether food resource availability could also operate as an ultimate driver of life-history strategy variation between species. During 13 years, we marked and recaptured young and adult sibling mouse-eared bats (Myotis myotis and Myotis blythii) at sympatric colonial sites. We tested whether distinct, species-specific trophic niches and food availability patterns may drive interspecific differences in key life-history components such as age at first reproduction and survival. We took advantage of a quasi-experimental setting in which prey availability for the two species varies between years (pulse vs. nonpulse resource years), modeling mark-recapture data for demographic comparisons. Prey availability dictated both adult survival and age at first reproduction. The bat species facing a more abundant and predictable food supply early in the season started its reproductive life earlier and showed a lower adult survival probability than the species subjected to more limited and less predictable food supply, while lifetime reproductive success was comparable in both species. The observed life-history trade-off indicates that temporal patterns in food availability can drive evolutionary divergence in life-history strategies among sympatric sibling species
The blubber adipocyte index: A nondestructive biomarker of adiposity in humpback whales (Megaptera novaeangliae)

The ability to accurately evaluate the energetic health of wildlife is of critical importance, particularly under conditions of environmental change. Despite the relevance of this issue, currently there are no reliable, standardized, nonlethal measures to assess the energetic reserves of large, free-roaming marine mammals such as baleen whales. This study investigated the potential of adipocyte area analysis and further, a standardized adipocyte index (AI), to yield reliable information regarding humpback whale (Megaptera novaeangliae) adiposity. Adipocyte area and AI, as ascertained by image analysis, showed a direct correlation with each other but only a weak correlation with the commonly used, but error prone, blubber lipid-percent measure. The relative power of the three respective measures was further evaluated by comparing humpback whale cohorts at different stages of migration and fasting. Adipocyte area, AI, and blubber lipid-percent were assessed by binary logistic regression revealing that adipocyte area had the greatest probability to predict the migration cohort with a high level of redundancy attributed to the AI given their strong linear relationship (r = −.784). When only AI and lipid-percent were assessed, the performance of both predictor variables was significant but the power of AI far exceeded lipid-percent. The sensitivity of adipocyte metrics and the rapid, nonlethal, and inexpensive nature of the methodology and AI calculation validate the inclusion of the AI in long-term monitoring of humpback whale population health, and further raises its potential for broader wildlife applications.Griffith Sciences, Griffith School of EnvironmentFull Tex
A complex speciation-richness relationship in a simple neutral model

Speciation is the "elephant in the room" of community ecology. As the
ultimate source of biodiversity, its integration in ecology's theoretical
corpus is necessary to understand community assembly. Yet, speciation is often
completely ignored or stripped of its spatial dimension. Recent approaches
based on network theory have allowed ecologists to effectively model complex
landscapes. In this study, we use this framework to model allopatric and
parapatric speciation in networks of communities and focus on the relationship
between speciation, richness, and the spatial structure of communities. We find
a strong opposition between speciation and local richness, with speciation
being more common in isolated communities and local richness being higher in
more connected communities. Unlike previous models, we also find a transition
to a positive relationship between speciation and local richness when dispersal
is low and the number of communities is small. Also, we use several measures of
centrality to characterize the effect of network structure on diversity. The
degree, the simplest measure of centrality, is found to be the best predictor
of local richness and speciation, although it loses some of its predictive
power as connectivity grows. Our framework shows how a simple neutral model can
be combined with network theory to reveal complex relationships between
speciation, richness, and the spatial organization of populations.Comment: 9 pages, 5 figures, 1 table, 50 reference
Universal expressions of population change by the Price equation:
  natural selection, information, and maximum entropy production

The Price equation shows the unity between the fundamental expressions of
change in biology, in information and entropy descriptions of populations, and
in aspects of thermodynamics. The Price equation partitions the change in the
average value of a metric between two populations. A population may be composed
of organisms or particles or any members of a set to which we can assign
probabilities. A metric may be biological fitness or physical energy or the
output of an arbitrarily complicated function that assigns quantitative values
to members of the population. The first part of the Price equation describes
how directly applied forces change the probabilities assigned to members of the
population when holding constant the metrical values of the members---a fixed
metrical frame of reference. The second part describes how the metrical values
change, altering the metrical frame of reference. In canonical examples, the
direct forces balance the changing metrical frame of reference, leaving the
average or total metrical values unchanged. In biology, relative reproductive
success (fitness) remains invariant as a simple consequence of the conservation
of total probability. In physics, systems often conserve total energy.
Nonconservative metrics can be described by starting with conserved metrics,
and then studying how coordinate transformations between conserved and
nonconserved metrics alter the geometry of the dynamics and the aggregate
values of populations. From this abstract perspective, key results from
different subjects appear more simply as universal geometric principles for the
dynamics of populations subject to the constraints of particular conserved
quantitiesComment: v2: Complete rewrite, new title and abstract. Changed focus to Price
  equation as basis for universal expression of changes in populations. v3:
  Cleaned up usage of terms virtual and reversible displacements and virtual
  work and usage of d'Alembert's principle. v4: minor editing and correction
Population structure of Purple Sandpipers (Calidris maritima) as revealed by mitochondrial DNA and microsatellites

The Purple Sandpiper (Calidris maritima) is a medium-sized shorebird that breeds in the Arctic and winters along northern Atlantic coastlines. Migration routes and affiliations between breeding grounds and wintering grounds are incompletely understood. Some populations appear to be declining, and future management policies for this species will benefit from understanding their migration patterns. This study used two mitochondrial DNA markers and 10 microsatellite loci to analyze current population structure and historical demographic trends. Samples were obtained from breeding locations in Nunavut (Canada), Iceland, and Svalbard (Norway) and from wintering locations along the coast of Maine (USA), Nova Scotia, New Brunswick, and Newfoundland (Canada), and Scotland (UK). Mitochondrial haplotypes displayed low genetic diversity, and a shallow phylogeny indicating recent divergence. With the exception of the two Canadian breeding populations from Nunavut, there was significant genetic differentiation among samples from all breeding locations; however, none of the breeding populations was a monophyletic group. We also found differentiation between both Iceland and Svalbard breeding populations and North American wintering populations. This pattern of divergence is consistent with a previously proposed migratory pathway between Canadian breeding locations and wintering grounds in the United Kingdom, but argues against migration between breeding grounds in Iceland and Svalbard and wintering grounds in North America. Breeding birds from Svalbard also showed a genetic signature intermediate between Canadian breeders and Icelandic breeders. Our results extend current knowledge of Purple Sandpiper population genetic structure and present new information regarding migration routes to wintering grounds in North America.Natural Sciences and Engineering Research Council of Canada; Environment CanadaPeer Reviewe
Behavioral evidence of hunting and foraging techniques by a top predator suggests the importance of scavenging for preadults

Scavenging may be a regular feeding behavior for some facultative raptor species oc-cupying  low  quality  habitats  and/or  with  little  experience  in  hunting  techniques. However, its importance has been largely underestimated due to methodological limi-tations in identifying the real proportion in the diet. Here, through direct observations, we  assessed  the  hunting  and  foraging  success  of  the  threatened  Spanish  imperial eagle Aquila adalberti determining the influence of age, sex, breeding status, habitat quality, prey type, and landscape characteristics. From 465 observations, Spanish im-perial eagles used hunting in flight (42%), scavenging (30%), hunting from a perch (16%) and kleptoparasitism (12%). Our model suggests that Prey size and Prey type best ex-plain  hunting  success,  followed  by  Landscape  and  Sex.  Our  findings  suggest  that Spanish imperial eagles increase hunting success with age, with scavenging and klep-toparasitism regularly used as juveniles. The absence of relationships with any of the variables considered suggests that kleptoparasitism is an opportunistic behavior used sporadically. Scavenging is also independent of habitat quality and landscape charac-teristics. Accordingly, low prey density is not a driver of carrion use for preadult indi-viduals,  suggesting  that  a  lack  of  hunting  ability  obliges  this  age- class  to  use  this alternative feeding technique regularly. As a result, the threatened Spanish imperial eagle population is also prone to mortality related to the illegal use of poison baits and, potentially, veterinary drugs (i.e., diclofenac).A.M. was supported by a Ramón y Cajal research contract by the Ministry of Economy and Competitiveness (RYC- 2012- 11867)
Evolutionary stability and the rarity of grandmothering

The provision of intergenerational care, via the Grandmother Hypothesis, has
been implicated in the evolution of post-fertile longevity, particularly in
humans. However, if grandmothering does provide fitness benefits, a key
question is why has it evolved so infrequently? We investigate this question
with a combination of life-history and evolutionary game theory. We derive
simple eligibility and stability thresholds, both of which must be satisfied if
intergenerational care is first to evolve and then to persist in a population.
As one threshold becomes easier to fulfill, the other becomes more difficult,
revealing a conflict between the two. As such, we suggest that, in fact, we
should expect the evolution of grandmothering to be rare.Comment: 4 pages, 1 figure. Submitte
Shifts in species richness, herbivore specialization, and plant resistance along elevation gradients.

Environmental gradients have been postulated to generate patterns of diversity and diet specialization, in which more stable environments, such as tropical regions, should promote higher diversity and specialization. Using field sampling and phylogenetic analyses of butterfly fauna over an entire alpine region, we show that butterfly specialization (measured as the mean phylogenetic distance between utilized host plants) decreases at higher elevations, alongside a decreasing gradient of plant diversity. Consistent with current hypotheses on the relationship between biodiversity and the strength of species interactions, we experimentally show that a higher level of generalization at high elevations is associated with lower levels of plant resistance: across 16 pairs of plant species, low-elevation plants were more resistant vis-à-vis their congeneric alpine relatives. Thus, the links between diversity, herbivore diet specialization, and plant resistance along an elevation gradient suggest a causal relationship analogous to that hypothesized along latitudinal gradients
Adaptation to fluctuating environments in a selection experiment with Drosophila melanogaster

A fundamental question in life-history evolution is how organisms cope with fluctuating environments, including variation between stressful and benign conditions. For short-lived organisms, environments commonly vary between generations. Using a novel experimental design, we exposed wild-derived Drosophila melanogaster to three different selection regimes: one where generations alternated between starvation and benign conditions, and starvation was always preceded by early exposure to cold; another where starvation and benign conditions alternated in the same way, but cold shock sometimes preceded starvation and sometimes benign conditions; and a third where conditions were always benign. Using six replicate populations per selection regime, we found that selected flies increased their starvation resistance, most strongly for the regime where cold and starvation were reliably combined, and this occurred without decreased fecundity or extended developmental time. The selected flies became stress resistant, displayed a pronounced increase in early life food intake and resource storage. In contrast to previous experiments selecting for increased starvation resistance in D. melanogaster, we did not find increased storage of lipids as the main response, but instead that, in particular for females, storage of carbohydrates was more pronounced. We argue that faster mobilization of carbohydrates is advantageous in fluctuating environments and conclude that the phenotype that evolved in our experiment corresponds to a compromise between the requirements of stressful and benign environments
Changes in phytophagous insect host ranges following the invasion of their community: Long-term data for fruit flies

The invasion of an established community by new species can trigger changes in community structure. Invasions often occur in phytophagous insect communities, the dynamics of which are driven by the structure of the host assemblage and the presence of competitors. In this study, we investigated how a community established through successive invasions changed over time, taking the last invasion as the reference. The community included four generalist and four specialist species of Tephritidae fruit flies. We analyzed a long-term database recording observed numbers of flies per fruit for each species on 36 host plants, over 18 years, from 1991 to 2009. Community structure before the last invasion by Bactrocera zonata in 2000 was described in relation to host plant phylogeny and resource availability. Changes in the host range of each species after the arrival of B. zonata were then documented by calculating diversity indices. The flies in the community occupied three types of niches defined on the basis of plant phylogeny (generalists, Solanaceae specialist, and Cucurbitaceae specialists). After the arrival of B. zonata, no change in the host range of specialist species was observed. However, the host ranges of two generalist species, Ceratitis quilicii and Ceratitis capitata, tended to shrink, as shown by the decreases in species richness and host plant α-diversity. Our study shows increased host specialization by generalist phytophagous insects in the field following the arrival of an invasive species sharing part of their resources. These findings could be used to improve predictions of new interactions between invaders and recipient communities. (Résumé d'auteur
The effects of elevated temperature and dissolved ρCO2 on a marine foundation species

Understanding how climate change and other environmental stressors will affect species is a fundamental concern of modern ecology. Indeed, numerous studies have documented how climate stressors affect species distributions and population persistence. However, relatively few studies have investigated how multiple climate stressors might affect species. In this study, we investigate the impacts of how two climate change factors affect an important foundation species. Specifically, we tested how ocean acidification from dissolution of CO2 and increased sea surface temperatures affect multiple characteristics of juvenile eastern oysters (Crassostrea virginica). We found strong impacts of each stressor, but no interaction between the two. Simulated warming to mimic heat stressed summers reduced oyster growth, survival, and filtration rates. Additionally, we found that CO2-induced acidification reduced strength of oyster shells, which could potentially facilitate crab predation. As past studies have detected few impacts of these stressors on adult oysters, these results indicate that early life stages of calcareous marine organisms may be more susceptible to effects of ocean acidification and global warming. Overall, these data show that predicted changes in temperature and CO2 can differentially influence direct effects on individual species, which could have important implications for the nature of their trophic interactions.ECU Open Access Publishing Fun
Habitat use and spatial fidelity of male South American sea lions during the nonbreeding period

Conditions experienced during the nonbreeding period have profound long-term effects on individual fitness and survival. Therefore, knowledge of habitat use during the nonbreeding period can provide insights into processes that regulate populations. At the Falkland Islands, the habitat use of South American sea lions (Otaria flavescens) during the nonbreeding period is of particular interest because the population is yet to recover from a catastrophic decline between the mid-1930s and 1965, and nonbreeding movements are poorly understood. Here, we assessed the habitat use of adult male (n = 13) and juvenile male (n = 6) South American sea lions at the Falkland Islands using satellite tags and stable isotope analysis of vibrissae. Male South American sea lions behaved like central place foragers. Foraging trips were restricted to the Patagonian Shelf and were typically short in distance and duration (127 ± 66 km and 4.1 ± 2.0 days, respectively). Individual male foraging trips were also typically characterized by a high degree of foraging site fidelity. However, the isotopic niche of adult males was smaller than juvenile males, which suggested that adult males were more consistent in their use of foraging habitats and prey over time. Our findings differ from male South American sea lions in Chile and Argentina, which undertake extended movements during the nonbreeding period. Hence, throughout their breeding range, male South American sea lions have diverse movement patterns during the nonbreeding period that intuitively reflects differences in the predictability or accessibility of preferred prey. Our findings challenge the long-standing notion that South American sea lions undertake a winter migration away from the Falkland Islands. Therefore, impediments to South American sea lion population recovery likely originate locally and conservation measures at a national level are likely to be effective in addressing the decline and the failure of the population to recover
Strength of density feedback in census data increases from slow to fast life histories

Life-history theory predicts an increasing rate of population growth among species arranged along a continuum from slow to fast life histories. We examine the effects of this continuum on density-feedback strength estimated using long-term census data from >700 vertebrates, invertebrates, and plants. Four life-history traits (Age at first reproduction, Body size, Fertility, Longevity) were related statistically to Gompertz strength of density feedback using generalized linear mixed-effects models and multi-model inference. Life-history traits alone explained 10 to 30% of the variation in strength across species (after controlling for time-series length and phylogenetic nonindependence). Effect sizes were largest for body size in mammals and longevity in birds, and density feedback was consistently stronger for smaller-bodied and shorter-lived species. Overcompensatory density feedback (strength <−1) occurred in 20% of species, predominantly at the fast end of the life-history continuum, implying relatively high population variability. These results support the idea that life history leaves an evolutionary signal in long-term population trends as inferred from census data. Where there is a lack of detailed demographic data, broad life-history information can inform management and conservation decisions about rebound capacity from low numbers, and propensity to fluctuate, of arrays of species in areas planned for development, harvesting, protection, and population recovery.Salvador Herrando-Pérez, Steven Delean, Barry W. Brook & Corey J. A. Bradsha