scholarly journals Population decline of the cape petrel (Daption capense) on King George Island, South Shetland Islands, Antarctica

Polar Biology ◽  
2021 ◽  
Author(s):  
Christina Braun ◽  
Jan Esefeld ◽  
Larisa Savelieva ◽  
Hans-Ulrich Peter
Keyword(s):  
Environmental Changes ◽  
Environmental Variability ◽  
Anthropogenic Impacts ◽  
Population Decline ◽  
Monitoring Program ◽  
South Shetland Islands ◽  
Fildes Peninsula ◽  
Breeding Sites ◽  
Shetland Islands

AbstractThe Antarctic and the surrounding Southern Ocean are currently subject to rapid environmental changes and increasing anthropogenic impacts. Seabird populations often reflect those changes and so act as indicators of environmental variability. Their population trends may provide information on a variety of environmental parameters on the scale of years or decades. We therefore provide long-term data on the cape petrel (Daption capense) population from a long-term monitoring program on Fildes Peninsula, South Shetland Islands, Maritime Antarctic, an area of considerable human activity. Our data, covering a period of 36 years, indicate some variability, but no clear trend in the number of breeding pairs between the breeding seasons 1985 and 2006. However, beginning in the 2008 season, the population decreased significantly and reached a minimum in the 2020 season. The mean annual decrease between 2008 and 2020 was 10.6%. We discuss possible causes of this strong negative population trend. Anthropogenic disturbance only affects a few breeding sites in the area and is therefore unable, on its own, to explain the consistent population decline at all the breeding sites studied. We think it more likely that reduced food availability was the main cause of the drastic decline in the cape petrel population.

scholarly journals Geomorphology and landforms distribution in selected ice-free areas in the South Shetland Islands, Antarctic Northern Peninsula region

2016 ◽  
Vol 42 (2) ◽  
pp. 435 ◽  
Author(s):  
J. López-Martínez ◽  
T. Schmid ◽  
E. Serrano ◽  
S. Mink ◽  
A. Nieto ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Environmental Changes ◽  
Weather Conditions ◽  
South Shetland Islands ◽  
The South ◽  
Fildes Peninsula ◽  
Shetland Islands ◽  
Highly Sensitive ◽  
Remote Sensing Techniques ◽  
Maxwell Bay

Ice-free areas cover a small percentage of the land in the South Shetland Islands. However, they are significant as they contain ecosystems highly sensitive to environmental changes and are located within a region affected by global warming. These areas are dominated by periglacial, glacial, fluvial, and coastal processes and landforms, where permafrost is often present. Soil development is observed although vegetation cover is sparse and closely related to the geomorphology. The mapping and monitoring of ice-free areas is important as they are highly sensitive to climate change. The objective of this study was to characterize and map surface landforms in ice-free areas using traditional mapping methods as well as advanced remote sensing techniques. Geomorphological and topographical maps were initially obtained through field measurements and observations, and complemented with existing aerial photography at scales between 1:2000 and 1:25000. Thereafter, satellite-borne data became available and were included in the methodology to further determine the distribution of the landforms. In the Antarctic environment, Synthetic Aperture Radar (SAR) provides the most reliable images as data can be obtained in any weather conditions as well as during the day and night. Fully polarimetric SAR RADARSAT-2 were used to determine seven different terrain classes representing surface landforms in ice-free areas around Maxwell Bay (King George Island). The SAR remote sensing techniques were successfully applied to identify different periglacial, fluvial, glacial, coastal, as well as lithological landforms. Field data from Fildes Peninsula were used to train a supervised classifier to map further areas around Maxwell Bay. In this case, the ice-free areas around Maxwell Bay clearly show the dominance of periglacial landforms and processes. Therefore, these techniques can be used to compare past and future results and to monitor areas affected by changing environmental factors and increasing human activities.

scholarly journals A Metacommunity Approach to Improve Biological Assessments in Highly Dynamic Freshwater Ecosystems

BioScience ◽  
2020 ◽  
Vol 70 (5) ◽  
pp. 427-438 ◽  
Author(s):  
Núria Cid ◽  
Núria Bonada ◽  
Jani Heino ◽  
Miguel Cañedo-Argüelles ◽  
Julie Crabot ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Environmental Variability ◽  
Anthropogenic Impacts ◽  
Dispersal Limitation ◽  
Freshwater Ecosystems ◽  
Metacommunity Ecology ◽  
Intermittent Rivers ◽  
Biological Assessments ◽  
Quality Assessments ◽  
Flow Intermittence

Abstract Rapid shifts in biotic communities due to environmental variability challenge the detection of anthropogenic impacts by current biomonitoring programs. Metacommunity ecology has the potential to inform such programs, because it combines dispersal processes with niche-based approaches and recognizes variability in community composition. Using intermittent rivers—prevalent and highly dynamic ecosystems that sometimes dry—we develop a conceptual model to illustrate how dispersal limitation and flow intermittence influence the performance of biological indices. We produce a methodological framework integrating physical- and organismal-based dispersal measurements into predictive modeling, to inform development of dynamic ecological quality assessments. Such metacommunity-based approaches could be extended to other ecosystems and are required to underpin our capacity to monitor and protect ecosystems threatened under future environmental changes.

scholarly journals Long-term Annual Aerial Surveys of Submersed Aquatic Vegetation (SAV) Support Science, Management, and Restoration

2019 ◽  
Author(s):  
Robert J. Orth ◽  
William C. Dennison ◽  
Cassie Gurbisz ◽  
Michael Hannam ◽  
Jeni Keisman ◽  
...  
Keyword(s):  
Aquatic Vegetation ◽  
New Technologies ◽  
Anthropogenic Impacts ◽  
Monitoring Program ◽  
Commercial Fishing ◽  
Submersed Aquatic Vegetation ◽  
Essential Information ◽  
Aerial Surveys ◽  
The Impact

Abstract Aerial surveys of coastal habitats can uniquely inform the science and management of shallow, coastal zones, and when repeated annually, they reveal changes that are otherwise difficult to assess from ground-based surveys. This paper reviews the utility of a long-term (1984–present) annual aerial monitoring program for submersed aquatic vegetation (SAV) in Chesapeake Bay, its tidal tributaries, and nearby Atlantic coastal bays, USA. We present a series of applications that highlight the program’s importance in assessing anthropogenic impacts, gauging water quality status and trends, establishing and evaluating restoration goals, and understanding the impact of commercial fishing practices on benthic habitats. These examples demonstrate how periodically quantifying coverage of this important foundational habitat answers basic research questions locally, as well as globally, and provides essential information to resource managers. New technologies are enabling more frequent and accurate aerial surveys at greater spatial resolution and lower cost. These advances will support efforts to extend the applications described here to similar issues in other areas.

The winter distribution of chinstrap penguins from two breeding sites in the South Shetland Islands of Antarctica

Polar Biology ◽  
2007 ◽  
Vol 30 (10) ◽  
pp. 1231-1237 ◽  
Author(s):  
Wayne Z. Trivelpiece ◽  
Stacey Buckelew ◽  
Christian Reiss ◽  
Susan G. Trivelpiece
Keyword(s):  
South Shetland Islands ◽  
The South ◽  
Breeding Sites ◽  
Shetland Islands ◽  
Winter Distribution

scholarly journals Changes in Ciliate Communities Reveal Modification of Lake Functioning Over the Last Century

2021 ◽  
Author(s):  
Barouillet Cécilia ◽  
Valentin Vasselon ◽  
François Keck ◽  
Laurent Millet ◽  
David Etienne ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Anthropogenic Impacts ◽  
Elevation Gradient ◽  
Holistic View ◽  
Β Diversity ◽  
Functional Community ◽  
Littoral Zones ◽  
Benthic Food ◽  
Lowland Lakes

Abstract Ciliates are unicellular heterotrophic organisms that play a key role in the planktonic and benthic food webs of lakes, and represent a great potential as bioindicator. In this study, we used the top-bottom paleolimnological approach to compare the recent and past (i.e. prior to major anthropogenic impacts) ciliate communities of 48 lakes located along an elevation gradient using metabarcoding techniques applied on sedimentary DNA (sed-DNA). Our results show an overall decline in the β-diversity in recent time, especially in lowland lakes which are more strongly expose to local human pressure. Analyses of the functional groups indicate important restructuration of the trophic food web and changes that are consistent with several well documented environmental changes such as the widespread increase in deep water anoxia, changes in thermal stability and nutrient cycling. Our study demonstrates the potential offered by sed-DNA to uncover information about past ciliate communities on a wide variety of lakes and the potential of using ciliates as valuable indicators, integrating information from the pelagic to the benthic profundal (and littoral) zones. Through trait-based functional community approach, the ciliates provide additional valuable information on ecosystem functioning, thus offering more a holistic view on the long-term changes of aquatic ecosystems.

Aulacoseira glubokoyensis sp. nov. (Bacillariophyceae), a new centric diatom from the Maritime Antarctic region

Phytotaxa ◽  
2017 ◽  
Vol 328 (2) ◽  
pp. 149
Author(s):  
ANNA BEATRIZ JONES OAQUIM ◽  
GLEYCI A.O. MOSER ◽  
HEITOR EVANGELISTA ◽  
MARCUS VINÍCIUS LICÍNIO ◽  
BART VAN DE VIJVER
Keyword(s):  
Dendritic Spines ◽  
South Shetland Islands ◽  
Similar Species ◽  
Centric Diatom ◽  
King George Island ◽  
Maritime Antarctic ◽  
Antarctic Region ◽  
Fildes Peninsula ◽  
Shetland Islands ◽  
Scanning Electron

A new centric diatom, Aulacoseira glubokoyensis sp. nov., is described from the Maritime Antarctic region. The morphology of the species is illustrated using detailed light and scanning electron microscopy observations. Its main discriminating features include the presence of typical irregularly shaped dendritic spines, at least two rimoportulae, marginal striae on the discus and a very large Ringleiste. The new species is compared to similar species worldwide. Aulacoseira glubokoyensis has only been observed in a sediment core taken from Profound Lake on the Fildes Peninsula (King George Island, South Shetland Islands).

Population viability and spatial fish reproductive strategies in constant and changing environments: an individual-based modelling approach

1997 ◽  
Vol 54 (10) ◽  
pp. 2235-2246 ◽  
Author(s):  
C LePage ◽  
P Cury
Keyword(s):  
Reproductive Strategies ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Reproductive Function ◽  
Population Level ◽  
Population Viability ◽  
Natural Systems ◽  
The Individual ◽  
Modelling Approach

A spatially explicit individual-based model (IBM) helps to explain how two reproductive strategies, described as obstinate and opportunist, may be acting at the population level. Factors such as the spatial structure and the dynamics of the environment, the shape of the reproductive function, and spawning season duration are considered. Five simulations are presented to explore the importance of these factors in the success of two reproductive strategies experiencing in a first step, a constant, and in a second step, a changing environment. Simulations show that the obstinate strategy is characterized by high inertia and mainly selects optimal environmental conditions in the long term, whereas the opportunist strategy maintains diversity in site choice and allows the individual to explore environmental variability. Under drastic environmental changes, only a population combining both strategies avoids extinction. A low percentage of opportunists (about 1%) coupled with a high proportion of obstinates (about 99%) ensure population viability. Similar percentages have been observed in nature for philopatric species. The respective percentages of inertia and innovation that are needed in the functioning of natural systems are discussed.

scholarly journals The deglaciation of Barton Peninsula (King George Island, South Shetland Islands, Antarctica) based on geomorphological evidence and lacustrine records

Polar Record ◽  
2019 ◽  
Vol 55 (3) ◽  
pp. 177-188 ◽  
Author(s):  
Marc Oliva ◽  
Dermot Antoniades ◽  
Enrique Serrano ◽  
Santiago Giralt ◽  
Emma J. Liu ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Environmental Changes ◽  
Lacustrine Sediments ◽  
South Shetland Islands ◽  
King George Island ◽  
Glacial Retreat ◽  
Radiocarbon Dates ◽  
Shetland Islands ◽  
Ice Cap ◽  
Barton Peninsula

AbstractBarton Peninsula is an ice-free area located in the southwest corner of King George Island (South Shetland Islands, Antarctica). Following the Last Glacial Maximum, several geomorphological features developed in newly exposed ice-free terrain and their distribution provide insights about past environmental evolution of the area. Three moraine systems are indicative of three main glacial phases within the long-term glacial retreat, which also favoured the development of numerous lakes. Five of these lakes were cored to understand in greater detail the pattern of deglaciation through the study of lacustrine records. Radiocarbon dates from basal lacustrine sediments enabled the reconstruction of the chronology of Holocene glacial retreat. Tephra layers present in lake sediments provided additional independent age constraints on environmental changes based on geochemical and geochronological correlation with Deception Island-derived tephra. Shrinking of the Collins Glacier exposed the southern coastal fringe of Barton Peninsula at 8 cal ky BP. After a period of relative stability during the mid-Holocene, the ice cap started retreating northwards after 3.7 cal ky BP, confining some glaciers within valleys as shown by moraine systems. Lake sediments confirm a period of relative glacial stability during the last 2.4 cal ky BP.

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