scholarly journals Terrestrial ecosystems of the Antarctic Peninsula and their responses to climate change and anthropogenic impacts

2020 ◽  
pp. 84-97
Author(s):  
R. Bargagli ◽  
Keyword(s):  
Antarctic Peninsula ◽  
Native Species ◽  
Environmental Changes ◽  
Anthropogenic Impacts ◽  
Extreme Temperature ◽  
Terrestrial Ecosystems ◽  
Indigenous Species ◽  
Non Indigenous Species ◽  
Food Web Complexity ◽  
The Antarctic

Antarctica and the Southern Ocean are unique natural laboratories where organisms adapted to extreme environmental conditions have evolved in isolation for millions of years. These unique biotic communities on Earth are facing complex climatic and environmental changes. Terrestrial ecosystems in the Antarctic Peninsula Region (APR) have experienced the highest rate of climate warming and, being the most impacted by human activities, are facing the greatest risk of detrimental changes. This review provides an overview of the most recent findings on how biotic communities in terrestrial ecosystems of the Antarctic Peninsula Region (APR) are responding and will likely respond to further environmental changes and direct anthropogenic impacts. Knowledge gained from studies on relatively simple terrestrial ecosystems could be very useful in predicting what may happen in much more complex ecosystems in regions with less extreme temperature changes. The rapid warming of the APR has led to the retreat of glaciers, the loss of snow and permafrost and the increase of ice-free areas, with a consequent enhancement of soil-forming processes, biotic communities, and food web complexity. However, most human activity is concentrated in APR coastal ice-free areas and poses many threats to terrestrial ecosystems such as environmental pollution or disturbances to soilcommunities and wildlife. People who work or visit APR may inadvertently introduce alien organisms and/or spread native species to spatially isolated ice-free areas. The number of introduced non-indigenous species and xenobiotic compounds in the APR is likely to be greater than currently documented, and several biosecurity and monitoring activities are therefore suggested to Antarctic national scientific programs and tourism operators to minimize the risk of irreversible loss of integrity by the unique terrestrial ecosystems of APR.

scholarly journals Responses of Southern Ocean Seafloor Habitats and Communities to Global and Local Drivers of Change

2021 ◽  
Vol 8 ◽  
Author(s):  
Madeleine J. Brasier ◽  
David Barnes ◽  
Narissa Bax ◽  
Angelika Brandt ◽  
Anne B. Christianson ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Indigenous Species ◽  
Drivers Of Change ◽  
Regional Warming ◽  
Commercial Fish ◽  
Key Species ◽  
Antarctic Shelf ◽  
Non Indigenous Species ◽  
The Antarctic ◽  
Slow Growing

Knowledge of life on the Southern Ocean seafloor has substantially grown since the beginning of this century with increasing ship-based surveys and regular monitoring sites, new technologies and greatly enhanced data sharing. However, seafloor habitats and their communities exhibit high spatial variability and heterogeneity that challenges the way in which we assess the state of the Southern Ocean benthos on larger scales. The Antarctic shelf is rich in diversity compared with deeper water areas, important for storing carbon (“blue carbon”) and provides habitat for commercial fish species. In this paper, we focus on the seafloor habitats of the Antarctic shelf, which are vulnerable to drivers of change including increasing ocean temperatures, iceberg scour, sea ice melt, ocean acidification, fishing pressures, pollution and non-indigenous species. Some of the most vulnerable areas include the West Antarctic Peninsula, which is experiencing rapid regional warming and increased iceberg-scouring, subantarctic islands and tourist destinations where human activities and environmental conditions increase the potential for the establishment of non-indigenous species and active fishing areas around South Georgia, Heard and MacDonald Islands. Vulnerable species include those in areas of regional warming with low thermal tolerance, calcifying species susceptible to increasing ocean acidity as well as slow-growing habitat-forming species that can be damaged by fishing gears e.g., sponges, bryozoan, and coral species. Management regimes can protect seafloor habitats and key species from fishing activities; some areas will need more protection than others, accounting for specific traits that make species vulnerable, slow growing and long-lived species, restricted locations with optimum physiological conditions and available food, and restricted distributions of rare species. Ecosystem-based management practices and long-term, highly protected areas may be the most effective tools in the preservation of vulnerable seafloor habitats. Here, we focus on outlining seafloor responses to drivers of change observed to date and projections for the future. We discuss the need for action to preserve seafloor habitats under climate change, fishing pressures and other anthropogenic impacts.

Sydney Harbour: a review of anthropogenic impacts on the biodiversity and ecosystem function of one of the world

2015 ◽  
Vol 66 (12) ◽  
pp. 1088 ◽  
Author(s):  
M. Mayer-Pinto ◽  
E. L. Johnston ◽  
P. A. Hutchings ◽  
E. M. Marzinelli ◽  
S. T. Ahyong ◽  
...  
Keyword(s):  
Sustainable Management ◽  
Anthropogenic Impacts ◽  
Habitat Modification ◽  
Indigenous Species ◽  
Benthic Community Structure ◽  
Organic Contamination ◽  
The World ◽  
Sydney Harbour ◽  
Biodiversity And Ecosystem Function ◽  
Non Indigenous Species

Sydney Harbour is a hotspot for diversity. However, as with estuaries worldwide, its diversity and functioning faces increasing threats from urbanisation. This is the first synthesis of threats and impacts in Sydney Harbour. In total 200 studies were reviewed: 109 focussed on contamination, 58 on habitat modification, 11 addressed non-indigenous species (NIS) and eight investigated fisheries. Metal concentrations in sediments and seaweeds are among the highest recorded worldwide and organic contamination can also be high. Contamination is associated with increased abundances of opportunistic species, and changes in benthic community structure. The Harbour is also heavily invaded, but invaders’ ecological and economic impacts are poorly quantified. Communities within Sydney Harbour are significantly affected by extensive physical modification, with artificial structures supporting more NIS and lower diversity than their natural equivalents. We know little about the effects of fishing on the Harbour’s ecology, and although ocean warming along Sydney is among the fastest in the world, we know little about how the ecosystem will respond to warming. The interactive and cumulative effects of stressors on ecosystem functioning and services in the Harbour are largely unknown. Sustainable management of this iconic natural system requires that knowledge gaps are addressed and translated into coherent environmental plans.

Seawater warming at the northern reach for southern species: Gulf of Genoa, NW Mediterranean

2017 ◽  
Vol 98 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Carlo Nike Bianchi ◽  
Francesco Caroli ◽  
Paolo Guidetti ◽  
Carla Morri
Keyword(s):  
Mediterranean Sea ◽  
Native Species ◽  
Indigenous Species ◽  
Ligurian Sea ◽  
The North ◽  
Nw Mediterranean ◽  
The Mediterranean ◽  
Non Indigenous Species ◽  
Southern Species ◽  
North Western

Global warming is facilitating the poleward range expansion of plant and animal species. In the Mediterranean Sea, the concurrent temperature increase and abundance of (sub)tropical non-indigenous species (NIS) is leading to the so-called ‘tropicalization’ of the Mediterranean Sea, which is dramatically evident in the south-eastern sectors of the basin. At the same time, the colder north-western sectors of the basin have been said to undergo a process of ‘meridionalization’, that is the establishment of warm-water native species (WWN) previously restricted to the southern sectors. The Gulf of Genoa (Ligurian Sea) is the north-western reach for southern species of whatever origin in the Mediterranean. Recent (up to 2015) observations of NIS and WWN by diving have been collated to update previous similar inventories. In addition, the relative occurrences of both groups of southern species have been monitored by snorkelling between 2009 and 2015 in shallow rocky reefs at Genoa, and compared with the trend in air and sea surface temperatures. A total of 20 southern species (11 NIS and 9 WWN) was found. Two WWN (the zebra seabream Diplodus cervinus and the parrotfish Sparisoma cretense) and three NIS (the SW Atlantic sponge Paraleucilla magna, the Red Sea polychaete Branchiomma luctuosum, and the amphi-American and amphi-Atlantic crab Percnon gibbesi) are new records for the Ligurian Sea, whereas juveniles of the Indo-Pacific bluespotted cornetfish Fistularia commersonii have been found for the first time. While temperature has kept on increasing for the whole period, with 2014 and 2015 being the warmest years since at least 1950, the number of WWN increased linearly, that of NIS increased exponentially, contradicting the idea of meridionalization and supporting that of tropicalization even in the northern sectors of the Mediterranean basin.

Climate change driven massive extirpation of native species from the Israeli Mediterranean shelf

2020 ◽  
Author(s):  
Paolo G. Albano ◽  
Jan Steger ◽  
Marija Bošnjak ◽  
Beata Dunne ◽  
Zara Guifarro ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Native Species ◽  
Large Scale ◽  
Seawater Temperature ◽  
Maximum Size ◽  
Extreme Environment ◽  
Time Range ◽  
Indigenous Species ◽  
Shallow Subtidal ◽  
Non Indigenous Species

<p>We quantify a large-scale extirpation of native species from the Israeli Mediterranean shelf, a region strongly affected by rapidly changing environmental conditions and the introduction of non-indigenous species, based on an extensive sampling programme of mollusks on intertidal to subtidal soft and hard substrata. We reconstruct historical species richness from shelly death assemblages, quantify the time range they cover with radiocarbon dating, and compare their richness with today’s living assemblage diversity. The median native richness is 50% of the historical richness for the intertidal, but only 8% for the subtidal down to 40 m. Samples from the mesophotic zone show a much higher median of 42%, which is likely an underestimation due to sampling constraints. In contrast, non-indigenous species show assemblages matching the historical richness. Seasonality is very strong: autumn samples, after the summer heat peak, are highly impoverished in native species but enriched in non-indigenous ones. Additionally, a comparison between today’s and historical native species maximum size shows that shallow subtidal native populations are mostly non-reproductive. In contrast, non-indigenous species reach reproductive size. These results suggest that a recent large-scale change in environmental conditions is strongly favoring non-indigenous species and is the main cause behind the shallow subtidal native species decline. Such an environmental factor is likely seawater temperature that plays a greater role in the shallow subtidal than in the cooler mesophotic zone, and affects subtidal species more than intertidal ones, pre-adapted to a climatically extreme environment.</p>

scholarly journals Disturbance, colonization and development of Antarctic benthic communities

2006 ◽  
Vol 362 (1477) ◽  
pp. 11-38 ◽  
Author(s):  
David K.A Barnes ◽  
Kathleen E Conlan
Keyword(s):  
Temperature Stress ◽  
Benthic Communities ◽  
Larval Abundance ◽  
Indigenous Species ◽  
Benthic Organisms ◽  
Community Recovery ◽  
Sea Floor ◽  
Wind Speeds ◽  
Non Indigenous Species ◽  
The Antarctic

A decade has yielded much progress in understanding polar disturbance and community recovery—mainly through quantifying ice scour rates, other disturbance levels, larval abundance and diversity, colonization rates and response of benthos to predicted climate change. The continental shelf around Antarctica is clearly subject to massive disturbance, but remarkably across so many scales. In summer, millions of icebergs from sizes smaller than cars to larger than countries ground out and gouge the sea floor and crush the benthic communities there, while the highest wind speeds create the highest waves to pound the coast. In winter, the calm associated with the sea surface freezing creates the clearest marine water in the world. But in winter, an ice foot encases coastal life and anchor ice rips benthos from the sea floor. Over tens and hundreds of thousands of years, glaciations have done the same on continental scales—ice sheets have bulldozed the seabed and the zoobenthos to edge of shelves. We detail and rank modern disturbance levels (from most to least): ice; asteroid impacts; sediment instability; wind/wave action; pollution; UV irradiation; volcanism; trawling; non-indigenous species; freshwater inundation; and temperature stress. Benthic organisms have had to recolonize local scourings and continental shelves repeatedly, yet a decade of studies have demonstrated that they have (compared with lower latitudes) slow tempos of reproduction, colonization and growth. Despite massive disturbance levels and slow recolonization potential, the Antarctic shelf has a much richer fauna than would be expected for its area. Now, West Antarctica is among the fastest warming regions and its organisms face new rapid changes. In the next century, temperature stress and non-indigenous species will drastically rise to become dominant disturbances to the Antarctic life. Here, we describe the potential for benthic organisms to respond to disturbance, focusing particularly on what we know now that we did not a decade ago.

scholarly journals Are there Invasive Planktonic Microbes?

2019 ◽  
Vol 2 (2) ◽  
Keyword(s):  
Natural Population ◽  
Human Activities ◽  
Environmental Changes ◽  
Common Species ◽  
Species Level ◽  
Indigenous Species ◽  
Introduced Populations ◽  
Interannual Fluctuations ◽  
Non Indigenous Species ◽  
Gymnodinium Catenatum

The translocation of species by human activities is a problem that increases with the globalization. However, the examples of non-indigenous or exotic planktonic microbes can be questioned as they predominantly have cosmopolitan distributions and natural mechanisms for wide dispersion. In reality, the categorization of any species as non-indigenous requires solving two difficult issues: knowledge of where the ‘natural’ population is, and demonstration of a substantial geographic discontinuity between the supposed source and the introduced populations. With regard to planktonic microorganisms, a non-indigenous taxon could have been previously unnoticed during routine microscopical analyses due to: A) difficult identification at the species level in routine observations such as for the diatoms (Pseudo-nitzschia, Skeletonema, Thalassiosira, Pleurosigma), unarmoured dinoflagellates (Karenia, Karlodinium) and Raphidophytes, and B) species with strong interannual fluctuations of abundance, only detected during bloom periods when they are misinterpreted as newcomers (i.e., Coscinodiscus wailesii or Trieres chinensis, junior synonyms of C. cylindricus and T. regia, respectively, or Gymnodinium catenatum). Rather than attempting to add to the lists of non-indigenous species with planktonic microbes, the monitoring surveys should also pay attention in the less common species with important fluctuations of abundance, independent of tentative labels as exotic or indigenous, because they are potentially useful as bio-indicators of environmental changes.

scholarly journals Comparative feeding behaviour of native and introduced terrestrial snails tracks their ecological impacts

NeoBiota ◽  
2019 ◽  
Vol 47 ◽  
pp. 81-94 ◽  
Author(s):  
Tedi Hoxha ◽  
Steve Crookes ◽  
Ian MacIsaac ◽  
Xuexiu Chang ◽  
Mattias Johansson ◽  
...  
Keyword(s):  
Functional Response ◽  
Feeding Behaviour ◽  
Native Species ◽  
Ecological Impact ◽  
Land Snails ◽  
Ecological Impacts ◽  
Food Type ◽  
Indigenous Species ◽  
Competitive Abilities ◽  
Non Indigenous Species

A developing body of theory and empirical evidence suggest that feeding behaviour as measured by the functional response (FR) can assist researchers in assessing the relative potential, ecological impacts and competitive abilities of native and introduced species. Here, we explored the FRs of two land snails that occur in south-western Ontario, one native (Mesodonthyroidus) and one non-indigenous (Cepaeanemoralis) to Canada. The non-indigenous species appears to have low ecological impact and inferior competitive abilities. Consistent with theory, while both species conformed to Type II functional responses, the native species had a significantly higher attack rate (5.30 vs 0.41, respectively) and slightly lower handling time (0.020 vs 0.023), and hence a higher maximum feeding rate (50.0 vs 43.5). The non-indigenous species exhibited a significantly longer time to contact for a variety of food types, and appeared less discriminating of paper that was offered as a non-food type. The non-indigenous species also ate significantly less food when in mixed species trials with the native snail. These feeding patterns match the known low ecological impact of the introduced snail and are consistent with the view that it is an inferior competitor relative to the native species. However, field experimentation is required to clarify whether the largely microallopatric distributions of the two species in south-western Ontario reflect competitive dominance by the native species or other factors such as habitat preference, feeding preferences or predator avoidance. The relative patterns of feeding behaviour and ecological impact are, however, fully in line with recent functional response theory and application.

Non-indigenous marine macroalgae in native communities: a case study in the British Isles

2008 ◽  
Vol 88 (4) ◽  
pp. 693-698 ◽  
Author(s):  
Frederic Mineur ◽  
Mark P. Johnson ◽  
Christine A. Maggs
Keyword(s):  
Species Richness ◽  
Northern Ireland ◽  
Community Composition ◽  
Native Species ◽  
Positive Relationship ◽  
Marine Macroalgae ◽  
Indigenous Species ◽  
Species Introduction ◽  
Southern England ◽  
Non Indigenous Species

It has traditionally been considered that areas with high natural species richness are likely to be more resistant to non-indigenous species than those with lower numbers of species. However, this theory has been the subject of a debate over the last decade, since some studies have shown the opposite trend. In the present study, a macroalgal survey was carried out at 24 localities in Northern Ireland and southern England, using a quadrat approach in the lower littoral. The two opposing hypotheses were tested (negative versus positive relationship between native and non-indigenous species richness) in this marine environment. The effect of the presence of ‘impacts’, potential sources of disturbance and species introduction (e.g. marina, harbour or aquaculture), was also tested. A positive relationship was found between the number of non-indigenous species and the native species richness at the three different scales tested (quadrats, sites and localities). At no scale did a richer native assemblage appear to restrict the establishment of introduced species. The analyses revealed greater species richness and different community composition, as well as more non-indigenous species, in southern England relative to Northern Ireland. The presence of the considered impacts had an effect on the community composition and species richness in southern England but not in Northern Ireland. Such impacts had no effect on the non-indigenous species richness in either area.

A primer to metabarcoding surveys of Antarctic terrestrial biodiversity

2016 ◽  
Vol 29 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Paul Czechowski ◽  
Laurence J. Clarke ◽  
Alan Cooper ◽  
Mark I. Stevens
Keyword(s):  
High Throughput Sequencing ◽  
Environmental Changes ◽  
Indigenous Species ◽  
Terrestrial Habitats ◽  
Cryptic Taxa ◽  
Terrestrial Biodiversity ◽  
Non Indigenous Species ◽  
Changes Over Time ◽  
Continental Interior ◽  
Highly Uniform

AbstractIce-free regions of Antarctica are concentrated along the coastal margins but are scarce throughout the continental interior. Environmental changes, including the introduction of non-indigenous species, increasingly threaten these unique habitats. At the same time, the unique biotic communities subsisting in isolation across the continent are difficult to survey due to logistical constraints, sampling challenges and problems related to the identification of small and cryptic taxa. Baseline biodiversity data from remote Antarctic habitats are still missing for many parts of the continent but are critical to the detection of community changes over time, including newly introduced species. Here we review the potential of standardized (non-specialist) sampling in the field (e.g. from soil, vegetation or water) combined with high-throughput sequencing (HTS) of bulk DNA as a possible solution to overcome some of these problems. In particular, HTS metabarcoding approaches benefit from being able to process many samples in parallel, while workflow and data structure can stay highly uniform. Such approaches have quickly gained recognition and we show that HTS metabarcoding surveys are likely to play an important role in continent-wide biomonitoring of all Antarctic terrestrial habitats.

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