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opencc-zeroNov 2020View details →

Local human population increase in the non-breeding areas of long-distance migrant bird species is only weakly associated with their declines, even for synanthropic species

Aim: To show how recent declines in populations of long-distance migrant birds are associated with recent increases in human population growth and agricultural intensification on their tropical non-breeding grounds, except for synanthropic species, where we expect the reverse. Location: Breeding populations throughout Europe and North America spending the non-breeding season throughout Africa, and Central and South America, respectively. Methods: We mapped 50 species of long-distance migrant birds from published tagging studies of 126 breeding populations and identified their breeding population trends from 2000-2015 from published Country or State census data. We then matched individual bird non-breeding locations, from each population, to local human population change and crop yield data. We used GLMs to predict whether bird population decline was associated with human population change or crop yield and whether this was dependent on if a species was synanthropic or not, controlling for absolute human population density, breeding and non-breeding location, migratory distance and phylogeny. We predicted that bird populations that spend the non-breeding season in areas of recent higher human population increase or agricultural intensification (crop yield), would show greater declines, but that declines would be less for species that frequently utilize anthropogenic habitats such as secondary woodland and farmland. Results: Bird population change, even for synanthropic species, showed a significant negative relationship with relative human population change and crop yield (but this was weak, <2% and 6% of variance respectively), and this relationship was the same for the Neotropics and Africa, despite African human population change being three times larger. Main conclusions: The results suggest that local human population change in the non-breeding area is likely to be only a relatively minor driver of migrant declines, and its effects may be through increases in agricultural intensification reducing carrying capacity but we currently lack local studies to confirm this.

Figure 5 from: Soreng RJ, Sylvester SP, Sylvester MDPV, Clark VR (2020) New records and key to Poa (Pooideae, Poaceae) from the Flora of Southern Africa region and notes on taxa including a diclinous breeding system in Poa binata. PhytoKeys 165: 27-50. https://doi.org/10.3897/phytokeys.165.55948

Figure 5 Poa nemoralis. A whole plant B close-up of inflorescence with spikelets in mostly lateral view. Image A of S.P. Sylvester et al. 3555 (US) B of S.P. Sylvester et al. 3555 (PRE).

Figure 1 from: Soreng RJ, Sylvester SP, Sylvester MDPV, Clark VR (2020) New records and key to Poa (Pooideae, Poaceae) from the Flora of Southern Africa region and notes on taxa including a diclinous breeding system in Poa binata. PhytoKeys 165: 27-50. https://doi.org/10.3897/phytokeys.165.55948

Figure 1 Poa binata. A whole plants B basal part of plant showing fibrous basal sheaths C, D portions of inflorescence. Image A of S.P. Sylvester et al. 3489 (US) B of S.P. Sylvester et al. 3412 (US) C of S.P. Sylvester et al. 3518 (US) D of S.P. Sylvester et al. 3677 (US).

Figure 4 from: Soreng RJ, Sylvester SP, Sylvester MDPV, Clark VR (2020) New records and key to Poa (Pooideae, Poaceae) from the Flora of Southern Africa region and notes on taxa including a diclinous breeding system in Poa binata. PhytoKeys 165: 27-50. https://doi.org/10.3897/phytokeys.165.55948

Figure 4 Poa infirma. A whole plants B–D close-up of inflorescence showing spikelets generally in lateral view and miniscule anthers (a). Image A, B of Smook 3576 (PRE0652756-0) C, D of Smook 3672 (PRE).

Figure 7 from: Soreng RJ, Sylvester SP, Sylvester MDPV, Clark VR (2020) New records and key to Poa (Pooideae, Poaceae) from the Flora of Southern Africa region and notes on taxa including a diclinous breeding system in Poa binata. PhytoKeys 165: 27-50. https://doi.org/10.3897/phytokeys.165.55948

Figure 7 Poa pratensis subsp. pratensis. A whole plant B junction of sheath and blade of tiller leaf showing glabrous collar C spikelet, lateral view D part of inflorescence with spikelets mostly in lateral view. Images of R.J. Soreng et al. ZA-33 (US).

Figure 8 from: Soreng RJ, Sylvester SP, Sylvester MDPV, Clark VR (2020) New records and key to Poa (Pooideae, Poaceae) from the Flora of Southern Africa region and notes on taxa including a diclinous breeding system in Poa binata. PhytoKeys 165: 27-50. https://doi.org/10.3897/phytokeys.165.55948

Figure 8 Poa trivialis. A whole plant B part of inflorescence with spikelets mostly in lateral view. Images of Meredith s.n. (PRE0021311-0).

Figure 6 from: Soreng RJ, Sylvester SP, Sylvester MDPV, Clark VR (2020) New records and key to Poa (Pooideae, Poaceae) from the Flora of Southern Africa region and notes on taxa including a diclinous breeding system in Poa binata. PhytoKeys 165: 27-50. https://doi.org/10.3897/phytokeys.165.55948

Figure 6 Poa pratensis subsp. irrigata. A whole plant B junction of sheath and blade of tiller leaf showing collar with ciliolate margin C part of inflorescence with spikelets in lateral view. Images of S.P. Sylvester et al. 3437 (US).

Figure 2 from: Soreng RJ, Sylvester SP, Sylvester MDPV, Clark VR (2020) New records and key to Poa (Pooideae, Poaceae) from the Flora of Southern Africa region and notes on taxa including a diclinous breeding system in Poa binata. PhytoKeys 165: 27-50. https://doi.org/10.3897/phytokeys.165.55948

Figure 2 Poa compressa. A whole plant B spikelets, lateral view C portion of inflorescence and leaf blade. Image A of S.P. Sylvester et al. 3439 (US) B of S.P. Sylvester et al. 3439 (PRE) C of J.P.H. Acocks 20227 (PRE).

Figure 3 from: Soreng RJ, Sylvester SP, Sylvester MDPV, Clark VR (2020) New records and key to Poa (Pooideae, Poaceae) from the Flora of Southern Africa region and notes on taxa including a diclinous breeding system in Poa binata. PhytoKeys 165: 27-50. https://doi.org/10.3897/phytokeys.165.55948

Figure 3 Poa iconia var. iconia. A whole plant B spikelet, lateral view C close-up of inflorescence. Images A, C of V.R. Clark & C. Kelly 269 (GRA0009104) B of V.R. Clark & C. Kelly 269 (PRE).

opencc-zeroNov 2020View details →

Data from: Latitudinal variation of arrival and breeding phenology of the pied flycatcher Ficedula hypoleuca using large-scale citizen science data.

Many species have advanced the timing of annual reproductive cycles in response to climatic warming, sometimes leading to asynchrony between trophic levels, with negative population consequences. Long-distance migratory birds, reliant on short seasonal food pulses for breeding, are considered particularly susceptible to such disjunction because late arrival may preclude optimal timing of egg-laying. It is unknown whether the relative timing of arrival and egg-laying is sufficiently plastic, in time and space, to enable an adaptive response when arrival times change relative to local food resources. We used citizen science data, describing pied flycatcher Ficedula hypoleuca arrival and egg-laying dates, to explore temporal (2013-2016) and spatial (across Great Britain) variation in the phenology of arrival, laying and their difference. To assess the long-term trend in arrival and laying at a single location, we used data from a long-term field study. The arrival-laying interval was consistently shorter in the north, driven by the contrast between spatial variation in arrival date and spatial invariance in laying date. To understand whether a short arrival-laying interval may have consequences for productivity, we assessed the association between this interval and clutch size. We found no statistically significant correlation between these two variables. To examine long-term changes in arrival and laying dates, we focussed on a single location in southwestern England. Both dates of first male arrival and first egg laid in a season advanced since 1986, with no evidence of interval shortening. Together, our results demonstrate spatial and annual variation in the arrival-laying interval, with no detected effect on fecundity. Thus, the interval from arrival to laying is likely dictated by spatially and temporally varying local conditions, suggesting these migrant birds may have the ability to adapt this interval to align with local conditions and mitigate potential mismatch impacts.

opencc-zeroDec 2020View details →

Data from: Mercury exposure in an endangered seabird: long-term changes and relationships with trophic ecology and breeding success

Mercury (Hg) is an environmental contaminant which, at high concentrations, can negatively influence avian physiology and demography. Albatrosses (Diomedeidae) have higher Hg burdens than all other avian families. Here, we measure total Hg (THg) concentrations of body feathers from adult grey-headed albatrosses (Thalassarche chrysostoma) at South Georgia. Specifically, we: (i) analyse temporal trends at South Georgia (1989–2013) and make comparisons with other breeding populations; (ii) identify factors driving variation in THg concentrations; and, (iii) examine relationships with breeding success. Mean ± SD feather THg concentrations were 13.0 ± 8.0 µg g-1 dw, which represents a threefold increase over the past 25 years at South Georgia and is the highest recorded in the Thalassarche genus. Foraging habitat, inferred from stable isotope ratios of carbon (δ13C), significantly influenced THg concentrations – feathers moulted in Antarctic waters had far lower THg concentrations than those moulted in subantarctic or subtropical waters. THg concentrations also increased with trophic level (δ15N), reflecting the biomagnification process. There was limited support for the influence of sex, age and previous breeding outcome on feather THg concentrations. However, in males, Hg exposure was correlated with breeding outcome – failed birds had significantly higher feather THg concentrations than successful birds. These results provide key insights into the drivers and consequences of Hg exposure in this globally important albatross population.

opencc-zeroDec 2020View details →

Personality-specific carry-over effects on breeding

Carry-over effects describe the phenomenon whereby an animal's previous conditions influence its subsequent performance. Carry-over effects are unlikely to affect individuals uniformly, but the factors modulating their strength are poorly known. Variation in the strength of carry-over effects may reflect individual differences in pace-of-life: slow-paced, shyly behaved individuals are thought to favour allocation to self-maintenance over current reproduction, compared to their fast-paced, boldly behaved conspecifics (the pace-of-life syndrome hypothesis). Therefore, detectable carry-over effects on breeding should be weaker in bolder individuals, as they should maintain allocation to reproduction irrespective of previous conditions, while shy individuals should experience stronger carry-over effects. We tested this prediction in black-legged kittiwakes breeding in Svalbard. Using miniature biologging devices, we measured non-breeding activity of kittiwakes, and monitored their subsequent breeding performance. We report a number of negative carry-over effects of non-breeding activity on breeding, which were generally stronger in shyer individuals: more active winters were followed by later breeding phenology and poorer breeding performance in shy birds, but these effects were weaker or undetected in bolder individuals. Our study quantifies individual variability in the strength of carry-over effects on breeding, and provides a mechanism explaining widespread differences in individual reproductive success.

opencc-zeroDec 2020View details →

Genetic diversity within and between British and Irish breeds: the maternal and paternal history of native ponies

The UK and Ireland have many native pony breeds, yet there is a lack of comprehensive research investigating their genetic diversity and phylogenetic interrelationships. Many studies contain a limited number of pony breeds, or small sample sizes for these breeds. This may result in erroneous grouping of pony breeds that otherwise have intricate interrelationships with each other and are not evaluated correctly when placed as a token subset of a larger dataset. This is the first study that specifically investigates the genetic diversity within and between British and Irish native pony breeds using large sample numbers from locations of their native origin. This study used a panel of microsatellite markers and sequence analysis of the mitochondrial control region to analyse the genetic diversity within and between 11 pony breeds from Britain and Ireland. A large dataset was collected and previously published data were used to place the British and Irish ponies in a global context. The native ponies of Britain and Ireland were found to have had a complex history and the interrelationships between the breeds were revealed. Overall, high levels of genetic diversity were present, including maintenance of rare ancient matrilines in the Welsh and Fell breeds. In contrast the Dartmoor showed limited maternal diversity. A number of unexpected shared ancestral origins were elucidated between some breeds. The data generated herein provides valuable information to guide and implement the conservation of increasingly rare native genetic resources.

Supplementary material 2 from: Lang A, Dolek M, Lee MS, Freese-Hager A, Otto M (2020) Selection of non-target Lepidoptera species to test Bt maize effects in the laboratory: which species and how to breed them? BioRisk 15: 45-65. https://doi.org/10.3897/biorisk.15.59823

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Supplementary material 1 from: Lang A, Dolek M, Lee MS, Freese-Hager A, Otto M (2020) Selection of non-target Lepidoptera species to test Bt maize effects in the laboratory: which species and how to breed them? BioRisk 15: 45-65. https://doi.org/10.3897/biorisk.15.59823

Reference list: breeding and rearing Lepidoptera

opencc-zeroDec 2021View details →

Data from: Greater sage-grouse survival varies with breeding season events in West Nile virus non-outbreak years

Greater Sage-Grouse (Centrocercus urophasianus) are a species of conservation concern and are highly susceptible to mortality from West Nile virus (WNV). Culex tarsalis, a mosquito species, is the suspected primary vector for transmitting WNV to sage-grouse. We captured, radio-tagged, and monitored female sage-grouse to estimate breeding season (April 15‒September 15) survival 2016-2017. Deceased sage-grouse were tested for active WNV; live captured and hunter harvested sage-grouse were tested for WNV antibody titers. Additionally, we trapped mosquitoes with CO2 baited traps 4 nights per week (542 trap nights) to estimate WNV minimum infection rate (MIR). Eight sage-grouse mortalities occurred during the WNV seasons of 2016 and 2017; 5 had recoverable tissue, and one of 5 tested positive for WNV infection. Survival varied temporally with sage-grouse biological seasons, not WNV seasonality. Survival was 0.68 (95% CI= 0.56–0.78; n=74) during the reproductive season (April 1−September 15). Mammalian predators were the leading suspected cause of mortality (40%), followed by unknown cause (25%), avian predation (15%), unknown predation (15%), and WNV (5%). These results indicate WNV was not a significant driver of adult sage-grouse survival during this study. Three sage-grouse (1.9%; 95% CI=0.5−5.9%) contained WNV antibodies. We captured 12,472 mosquitoes of which 3,933 (32%) were Culex tarsalis. Estimated WNV MIR of Culex tarsalis during 2016 and 2017 was 3.3 and 1.6, respectively. Our results suggest sage-grouse in South Dakota have limited exposure to WNV, and WNV was not a significant source of sage-grouse mortality in South Dakota during 2016 and 2017. Based on our finding that a majority of sage-grouse in South Dakota are susceptible to WNV infection, WNV could potentially have an impact on the population during an epizootic event; however, when WNV is at or near endemic levels, it appears to have little impact on sage-grouse survival.

Habitat-specific survival of golden-winged warblers (Vermivora chrysoptera) during the non-breeding season in an agricultural landscape

Nearctic-Neotropical migratory birds are considered priority species for conservation because they are subject to threats at distinct breeding, migratory and stopover locations throughout their annual cycle, and many species have undergone severe population declines. Research during the non-breeding season has focused on identifying the locations and habitats that migrants use, but wintering migrants are known to occupy habitats of both high and low quality, especially when the best sites are saturated by conspecifics. Thus, the presence or abundance of a species may not be a reliable indicator of winter habitat quality. The habitat associations of the golden-winged warbler Vermivora chrysoptera, a Nearctic-Neotropical migrant bird species of elevated conservation concern, are relatively well studied, yet conservation efforts are hindered by lack of information about basic demographic rates. In particular, no published estimates exist for non-breeding season survival, which can be a key vital rate affecting population viability, nor how survival rates vary among habitats, which is important to designing conservation programs to support populations during the winter period. We studied a color-banded population of golden-winged warblers in Costa Rica over a 3-year period and estimated overall survival rates, and the effects of habitat characteristics on survival. We found that monthly survival of juveniles (0.881) was lower than adult birds (0.978). Monthly survival during the non-breeding season (0.967) was higher than monthly survival during the rest of the annual cycle (0.930). Survival was negatively related to canopy height, and we observed a significant quadratic effect where survival peaked at intermediate levels of vine tangles and dead hanging leaves, which corresponds to habitat features associated with abundance in prior studies at this same site. Our findings contribute to our existing knowledge about the potential impacts of winter-season events on Nearctic-Neotropical migratory bird populations, and also informs potential conservation strategies for wintering golden-winged warblers.

Data from: Local prey shortages drive foraging costs and breeding success in a declining seabird, the Atlantic puffin

As more and more species face anthropogenic threats, understanding causes of population declines in vulnerable taxa is essential. However, long-term datasets, ideal to identify lasting or indirect effects on fitness measures such as those caused by environmental factors, are not always available. Here we use a single year but multi-population approach on populations with contrasting demographic trends to identify possible drivers and mechanisms of seabird population changes in the north-east Atlantic, using the Atlantic puffin, a declining species, as a model system. We combine miniature GPS trackers with camera traps and DNA metabarcoding techniques on four populations across the puffins' main breeding range to provide the most comprehensive study of the species' foraging ecology to date. We find that puffins use a dual foraging tactic combining short and long foraging trips in all four populations, but declining populations in southern Iceland and north-west Norway have much greater foraging ranges, which require more (costly) flight, as well as lower chick-provisioning frequencies, and a more diverse but likely less energy-dense diet, than stable populations in northern Iceland and Wales. Together, our findings suggest that the poor productivity of declining puffin populations in the north-east Atlantic is driven by breeding adults being forced to forage far from the colony, presumably because of low prey availability near colonies, possibly amplified by intraspecific competition. Our results provide valuable information for the conservation of this and other important North-Atlantic species and highlight the potential of multi-population approaches to answer important questions about the ecological drivers of population trends.

opencc-zeroDec 2014View details →

Data from: No apparent benefits of allonursing for recipient offspring and mothers in the cooperatively breeding meerkat

1. Cooperative behaviours by definition are those that provide some benefit to another individual. Allonursing, the nursing of non-descendent young, is often considered a cooperative behaviour and is assumed to provide benefits to recipient offspring in terms of growth and survival, and to their mothers, by enabling them to share the lactation load. However, these proposed benefits are not well understood, in part because maternal and litter traits and other ecological and social variables are not independent of one another, making patterns hard to discern using standard univariate analyses. 2. Here, we investigate the potential benefits of allonursing in the cooperatively breeding Kalahari meerkat, where socially subordinate females allonurse the young of a dominant pair without having young of their own. 3. We use structural equation modelling to allow us to account for the interdependence of maternal traits, litter traits and environmental factors. 4. We find no evidence that allonursing provides benefits to pups or mothers. Pups that received allonursing were not heavier at emergence and did not have a higher survival rate than pups that did not receive allonursing. Mothers whose litters were allonursed were not in better physical condition, did not reconceive faster and did not reduce their own nursing investment compared to mothers who nursed their litters alone. These patterns were not significantly influenced by whether mothers were in relatively good, or poor, condition. 5. We suggest that allonursing may persist in this species because the costs to allonurses may be low. Alternatively, allonursing may confer other, more cryptic, benefits to pups or allonurses, such as immunological or social benefits.