Małgorzata Korczak-Abshire

Diaspores and phyto-remains accidentally transported to the Antarctic Station during three expeditions

The aim of the project was to assess the size and species range of alien plant diaspores and phyto-remains transported into the Polish Antarctic Station during three Antarctic expeditions. Our study clearly demonstrates that many diaspores can be quite easily unintentionally transported in good conditions to the Antarctic. In the analyzed material there were present diaspores of invasive species. All identified species belong to 20 families. The most abundant were Asteraceae and Poaceae species. The most interesting finding was the presence of caryopses of Poa annua, the first alien angiosperm species which already established a stable breeding population in the Antarctic. Base on our results, we can predict that risk of establishment of anther alien plant species in the vicinity of “Arctowski” Station is very high.

Records of white-rumped sandpiper (Calidris fuscicollis) on the South Shetland Islands

A programme to monitor non-breeding bird species in the vicinity of Arctowski Station, King George Island, South Shetlands, Antarctica, has been conducted over the past 30 years. The white-rumped sandpiper Calidris fuscicollis (Vieillot 1819) seems to occur now as a vagrant in South Shetlands area more frequently than previously. This trend, and the annual variation in numbers that have been observed could be a result of short term and longer term variation in weather and climate conditions during the austral spring and summer months when this species is observed. A higher air temperature, which is a result of predominant northern winds bringing relatively warm and moist air, would probably result in more open habitats and better food resources that would allow the birds to persist or survive.

What affects the probability of biological invasions in Antarctica? Using an expanded conceptual framework to anticipate the risk of alien species expansion

Successful alien species invasion depends on many factors studied mostly in post invasion habitats, and subsequently summarized in frameworks tailored to describe the studied invasion. We used an existing expanded framework with three groups of contributing factors: habitat invisibility, system context and species invasiveness, to analyze the probability of alien species invasions in terrestrial communities of Maritime Antarctic in the future. We focused on the first two factor groups. We tested if the expanded framework could be used under a different scenario. We chose Point Thomas Oasis on King George Island to perform our analysis. Strong geographical barrier, low potential bioclimatic suitability and resource availability associated with habitat invasibility significantly reduce the likelihood of biological invasion in Antarctica. An almost full enemy release (low pressure of consumers), the high patchiness of the habitat, and the prevalence of open gaps also associated with habitat invasibility increase the possibility of invasion. The dynamics of functional connectivity, propagule pressure and spatio-temporal patterns of propagule arrival associated with human activity and climate change belonging to the system context contribute to an increase in the threat of invasions. Due to the still low land transport activity migration pathways are limited and will reduce the spread of alien terrestrial organisms by land. An effective way of preventing invasions in Antarctica seems to lie in reducing propagule pressure and eliminating alien populations as early as possible. The expanded conceptual framework opens up wider possibilities in analyzing invasions taking place in different systems and with multiple taxa.

Estimating nest‐level phenology and reproductive success of colonial seabirds using time‐lapse cameras

1. Collecting spatially extensive data on phenology and reproductive success is important for seabird conservation and management, but can be logistically challenging in remote regions. Autonomous time‐lapse camera systems offer an opportunity to provide such coverage. 2. We describe a method to estimate nest‐level breeding phenology and reproductive success of colonial pygoscelid penguins using photographs from time‐lapse cameras. The method derives from stereotypical patterns of nest attendance, where predominantly two adults are present before and during laying, but switch to one adult during incubation. The switch approximates the date of clutch completion and is estimated by fitting a smoothing spline to daily nest attendance data, identifying candidate dates that switch from two adults to one and selecting the date when the first derivative of the spline is minimized. Clutch initiation and hatch dates are then estimated from the mean, species‐specific interval between laying (pygoscelid penguins typically lay two eggs) and the duration of the incubation period. We estimated these intervals for each species from historical field data. The phenology is adjusted when photographs indicate egg or chick presence prior to their estimated lay or hatch dates. The number of chicks alive in each study nest on its creche date determines reproductive success estimates. The method was validated with concurrent direct observations for each species and then applied to a camera network in the Antarctic Peninsula region to demonstrate its utility. 3. Mean egg laying and incubation intervals from direct observations were similar within species across sites. In the validation study, the mean clutch initiation, hatch and creche dates were generally equivalent between photographs and direct observations. Estimates of reproductive success were identical. Applying the method to a time‐lapse network suggested relatively high reproductive success for all species across the region and corroborated general understanding of latitudinal trends and species‐level plasticity in phenology. 4. The method accurately estimated phenology and reproductive success relative to direct observations and appears well‐suited to operationalize regional time‐lapse camera networks. The estimation method should be applicable for other seabirds with stereotypical nest attendance patterns from which breeding phenology could be estimated.