Landslide investigations during pandemic restrictions: initial assessment of recent peat landslides in Ireland

Landslides involving peat are relatively common in Ireland, upland areas of Great Britain and subantarctic islands. Bogflows and bog slides are less common types of peat failure and almost unknown outside Ireland. Unusually, three of these occurred in 2020 including one bogflow at a windfarm that gained much adverse media attention, and a small but damaging peat slide was also reported. The aim of this paper is to determine the extent to which the new bog slide and bogflows are consistent with previous examples in terms of their contexts, characteristics and possible causes, particularly relating to commercial forestry operations. Aerial video footage of all three landslides obtained by local people using drones, and ground-based footage of one of them in progress, allowed a detailed examination of their characteristics and contexts to be made despite the global travel and activity restrictions caused by the coronavirus pandemic. The windfarm bogflow appears to have resulted from removal of toe support by an earlier peat flow that was itself probably caused by construction of an access road; the other two landslides were most likely triggered by rainfall. All three are consistent with previous examples of their respective types in their general characteristics and appear to be associated with well-known causal factors including hydrological, topographic and/or forestry influences. Forestry operations probably contributed to the occurrence of two of the landslides and restricted the expansion of two of them.

Gastrointestinal Microbiota and Parasite-Fauna of Wild Dissostichus eleginoides Smitt, 1898 Captured at the South-Central Coast of Chile

Dissotichus eleginoides has a discontinuous circumpolar geographic distribution restricted to mountains and platforms, mainly in Subantarctic and Antarctic waters of the southern hemisphere, including the Southeast Pacific, Atlantic and Indian oceans and in areas surrounding the peninsular platforms of subantarctic islands. The aim of this work was to determine and characterize the gastrointestinal parasitic and microbial fauna of specimens of D. eleginoides captured in waters of the south-central zone of Chile. The magnitude of parasitism in D. eleginoides captured in waters of the south-central zone of Chile is variable, and the parasite richness is different from that reported in specimens from subantarctic environments. Next-generation sequencing (NGS) of the microbial community associated to intestine showed a high diversity, where Proteobacteria, Firmicutes, and Bacteriodetes were the dominant phyla. However, both parasitic and microbial structures can vary between fish from different geographic regions

Trophic interactions and ecosystem management at the New Zealand Subantarctic Islands

<p>Ecosystem-based management (EBM) has become an increasingly popular concept for government agencies to incorporate into management planning strategies. The basic idea behind EBM is that an ecosystem remains intact, resilient and productive in the long-term, to provide for ecological, social, cultural and economic benefits. The problem that decision makers face is that there is often little information regarding the structure and functioning of ecosystems upon which to base meaningful decisions. A further complication is that governance of the environment is highly sectoral both across government and within agencies. This often leads to fractured management between the terrestrial, freshwater and marine environments, potentially risking biodiversity loss and the stability of ecosystems. Small oceanic islands may potentially be model ecosystems for undertaking ecological studies, due to their constrained spatial extent and often unmodified condition. The New Zealand Subantarctic Islands, which are remote and largely unmodified, provide a natural laboratory to study the structure and functioning of ecosystems. I undertook stable isotope and water nutrient sampling to describe the trophic structure, trophic interactions and the drivers of the Antipodes and Bounty Islands, two of the islands in New Zealand’s Subantarctic region. These islands have high conservation value and are an important area for breeding seabirds and marine mammals, but there have been no studies at these islands to understand how they function and what the connections are between the terrestrial and marine environments. Using the stable isotope signatures of nitrogen (δ¹⁵N) and carbon (δ¹³C) from a wide range of common marine and terrestrial species at both islands, I described the trophic structure of each island. I found that the islands had a similar number of trophic levels and that omnivory was present beyond secondary consumers and below top level predators. Antipodes Island had a more complex food web than the Bounty Islands, but both islands showed strong linkages between the terrestrial and marine environments at both a local scale and with habitats beyond the sovereignty area of New Zealand. A basic two-source mixing model was used to determine the carbon sources that were important at each island. It was found that the Antipodes Island marine communities were influenced by phytoplankton, but that kelp was also an important contributor of carbon to consumers’ diets. In contrast, at the Bounty Islands, phytoplankton was the sole carbon source in marine communities. Terrestrial species at both islands had a marine-derived carbon component to their diets, with Antipodes Island terrestrial species incorporating a combination of terrestrial-derived and marine-derived carbon. The Bounty Islands’ terrestrial species were completely reliant on marine-derived carbon that was linked to phytoplankton. To further test the diets of species, Isosource was used to reconstruct the diets of the most common marine invertebrates and terrestrial species, again demonstrating strong marine-terrestrial links. To determine if there was any correlation between the distance from shore, water nutrient concentrations and phytoplankton stable isotope signatures, samples were collected in open ocean sites across the Campbell Plateau and within 12 nautical miles of each island. It was found that the nitrate levels of Antipodes Island water samples decreased with distance towards the island and that nitrate and dissolved reactive phosphorous levels increased with distance towards the Bounty Islands. This research has clearly demonstrated that there is a strong link between the marine and terrestrial realms at both islands and at spatial scales beyond the islands. The current management of the islands requires this new information to be taken into consideration in future management planning, so that trophic connections are maintained across realms. Further work is required across government and within agencies to bring legislation, policy and science into an integrated framework across sectors. This will allow environmental managers to reduce threats at the ecosystem level to minimise biodiversity loss and the risk of degradation of ecosystems, to protect New Zealand’s long-term biodiversity, social, cultural and economic prosperity.</p>

Trophic interactions and ecosystem management at the New Zealand Subantarctic Islands

<p>Ecosystem-based management (EBM) has become an increasingly popular concept for government agencies to incorporate into management planning strategies. The basic idea behind EBM is that an ecosystem remains intact, resilient and productive in the long-term, to provide for ecological, social, cultural and economic benefits. The problem that decision makers face is that there is often little information regarding the structure and functioning of ecosystems upon which to base meaningful decisions. A further complication is that governance of the environment is highly sectoral both across government and within agencies. This often leads to fractured management between the terrestrial, freshwater and marine environments, potentially risking biodiversity loss and the stability of ecosystems. Small oceanic islands may potentially be model ecosystems for undertaking ecological studies, due to their constrained spatial extent and often unmodified condition. The New Zealand Subantarctic Islands, which are remote and largely unmodified, provide a natural laboratory to study the structure and functioning of ecosystems. I undertook stable isotope and water nutrient sampling to describe the trophic structure, trophic interactions and the drivers of the Antipodes and Bounty Islands, two of the islands in New Zealand’s Subantarctic region. These islands have high conservation value and are an important area for breeding seabirds and marine mammals, but there have been no studies at these islands to understand how they function and what the connections are between the terrestrial and marine environments. Using the stable isotope signatures of nitrogen (δ¹⁵N) and carbon (δ¹³C) from a wide range of common marine and terrestrial species at both islands, I described the trophic structure of each island. I found that the islands had a similar number of trophic levels and that omnivory was present beyond secondary consumers and below top level predators. Antipodes Island had a more complex food web than the Bounty Islands, but both islands showed strong linkages between the terrestrial and marine environments at both a local scale and with habitats beyond the sovereignty area of New Zealand. A basic two-source mixing model was used to determine the carbon sources that were important at each island. It was found that the Antipodes Island marine communities were influenced by phytoplankton, but that kelp was also an important contributor of carbon to consumers’ diets. In contrast, at the Bounty Islands, phytoplankton was the sole carbon source in marine communities. Terrestrial species at both islands had a marine-derived carbon component to their diets, with Antipodes Island terrestrial species incorporating a combination of terrestrial-derived and marine-derived carbon. The Bounty Islands’ terrestrial species were completely reliant on marine-derived carbon that was linked to phytoplankton. To further test the diets of species, Isosource was used to reconstruct the diets of the most common marine invertebrates and terrestrial species, again demonstrating strong marine-terrestrial links. To determine if there was any correlation between the distance from shore, water nutrient concentrations and phytoplankton stable isotope signatures, samples were collected in open ocean sites across the Campbell Plateau and within 12 nautical miles of each island. It was found that the nitrate levels of Antipodes Island water samples decreased with distance towards the island and that nitrate and dissolved reactive phosphorous levels increased with distance towards the Bounty Islands. This research has clearly demonstrated that there is a strong link between the marine and terrestrial realms at both islands and at spatial scales beyond the islands. The current management of the islands requires this new information to be taken into consideration in future management planning, so that trophic connections are maintained across realms. Further work is required across government and within agencies to bring legislation, policy and science into an integrated framework across sectors. This will allow environmental managers to reduce threats at the ecosystem level to minimise biodiversity loss and the risk of degradation of ecosystems, to protect New Zealand’s long-term biodiversity, social, cultural and economic prosperity.</p>

Speciation, Connectivity and Self-Recruitment Among Mollusc Populations from Isolated Oceanic Islands

<p>The conventional view that marine populations are demographically ‘open’ and exchange migrants (juveniles or adults, but mostly larvae) has been challenged by recent genetic studies and the discovery of significant genetic subdivision among populations on small geographic scales. Despite the numerous publications on the matter, the extent to which some/all marine populations rely on self-recruitment and whether this reliance is stable in time and space currently remains unanswered. This is particularly true for populations from isolated oceanic archipelagos, such as the New Zealand (NZ) subantarctic islands and the Kermadec Islands. The specific objectives of this thesis were to: 1) assess the genetic diversity, phylogeography and contemporary levels of dispersal and self-recruitment in populations of the Cellana strigilis limpet complex, endemic to the NZ subantarctic islands; 2) conduct a morphometric analysis of the C. strigilis complex to complement its molecular investigation; 3) develop and optimize specific microsatellite markers for Nerita melanotragus, a marine gastropod of the Kermadec Islands and New Zealand North Island rocky shores; 4) assess the genetic structuring and levels of connectivity of N. melanotragus populations within the Kermadec Islands, within NZ North Island, and between the Kermadec Islands and NZ; and 5) compare the genetic structuring of N. melanotragus at the Kermadec Islands to that of NZ North Island populations, to test for any “island effect” on connectivity levels, and test for possible gene flow between the two groups. Genetic investigation of the C. strigilis complex confirmed the presence of two distinct lineages, separated by their sister species Cellana denticulata. Morphometric analyses were congruent with molecular analyses, and were used to provide a new taxonomic description of the C. strigilis limpet complex: two species were recognized, Cellana strigilis and Cellana oliveri. The role of the subantarctic islands during the last glacial maximum was highlighted, and the colonisation history of the islands by the two Cellana species was explained. Contemporary levels of connectivity (gene flow) among the different populations of the two lineages were low, or non-existant, revealing their high reliability on self-recruitment. However, the analysis detected a recent migration event in one of the two lineages. Considering the geographical distance of the islands and the life history of the Cellana species, the use of mediated dispersal means (e.g., rafting on a natural substrate such as kelp) seems very likely. Ten novel polymorphic microsatellite loci were developed for N. melanotragus, and seven of those were used to investigate the levels of connectivity and self-recruitment in six populations from the Kermadec Islands, and nine populations from the east coast of NZ North Island. According to what can be expected for a species with a long pelagic larval duration (PLD), genetic homogeneity was recorded for the Kermadec Islands populations. A lack of genetic structuring was also found for the nine populations on the NZ North Island, which is congruent with the literature in this geographic area. However, what was surprising was the high level of genetic homogeneity found between the Kermadec Islands and the NZ North Island, meaning that the two groups are effectively exchanging individuals. Hence, the Kermadec archipelago can be considered “open” at the scale of the South Pacific, for N. melanotragus populations. This Ph.D. highlights the importance of having the correct taxonomy for conservation and connectivity studies, and gives a better understanding of the historical and contemporary patterns of genetic connectivity in the NZ offshore islands. It illustrated how historical events, such as the last glacial maximum, can shape local genetic diversity, and how this historical pattern can be maintained because of limited contemporary gene exchange. Also, this thesis demonstrated that remote populations could be strongly connected to mainland populations, contributing to the resilience of both systems and confirming the necessity of integrating remote oceanic habitats in the creation of effective Marine Protected Areas (MPA) networks to protect the marine environment.</p>

Speciation, Connectivity and Self-Recruitment Among Mollusc Populations from Isolated Oceanic Islands

<p>The conventional view that marine populations are demographically ‘open’ and exchange migrants (juveniles or adults, but mostly larvae) has been challenged by recent genetic studies and the discovery of significant genetic subdivision among populations on small geographic scales. Despite the numerous publications on the matter, the extent to which some/all marine populations rely on self-recruitment and whether this reliance is stable in time and space currently remains unanswered. This is particularly true for populations from isolated oceanic archipelagos, such as the New Zealand (NZ) subantarctic islands and the Kermadec Islands. The specific objectives of this thesis were to: 1) assess the genetic diversity, phylogeography and contemporary levels of dispersal and self-recruitment in populations of the Cellana strigilis limpet complex, endemic to the NZ subantarctic islands; 2) conduct a morphometric analysis of the C. strigilis complex to complement its molecular investigation; 3) develop and optimize specific microsatellite markers for Nerita melanotragus, a marine gastropod of the Kermadec Islands and New Zealand North Island rocky shores; 4) assess the genetic structuring and levels of connectivity of N. melanotragus populations within the Kermadec Islands, within NZ North Island, and between the Kermadec Islands and NZ; and 5) compare the genetic structuring of N. melanotragus at the Kermadec Islands to that of NZ North Island populations, to test for any “island effect” on connectivity levels, and test for possible gene flow between the two groups. Genetic investigation of the C. strigilis complex confirmed the presence of two distinct lineages, separated by their sister species Cellana denticulata. Morphometric analyses were congruent with molecular analyses, and were used to provide a new taxonomic description of the C. strigilis limpet complex: two species were recognized, Cellana strigilis and Cellana oliveri. The role of the subantarctic islands during the last glacial maximum was highlighted, and the colonisation history of the islands by the two Cellana species was explained. Contemporary levels of connectivity (gene flow) among the different populations of the two lineages were low, or non-existant, revealing their high reliability on self-recruitment. However, the analysis detected a recent migration event in one of the two lineages. Considering the geographical distance of the islands and the life history of the Cellana species, the use of mediated dispersal means (e.g., rafting on a natural substrate such as kelp) seems very likely. Ten novel polymorphic microsatellite loci were developed for N. melanotragus, and seven of those were used to investigate the levels of connectivity and self-recruitment in six populations from the Kermadec Islands, and nine populations from the east coast of NZ North Island. According to what can be expected for a species with a long pelagic larval duration (PLD), genetic homogeneity was recorded for the Kermadec Islands populations. A lack of genetic structuring was also found for the nine populations on the NZ North Island, which is congruent with the literature in this geographic area. However, what was surprising was the high level of genetic homogeneity found between the Kermadec Islands and the NZ North Island, meaning that the two groups are effectively exchanging individuals. Hence, the Kermadec archipelago can be considered “open” at the scale of the South Pacific, for N. melanotragus populations. This Ph.D. highlights the importance of having the correct taxonomy for conservation and connectivity studies, and gives a better understanding of the historical and contemporary patterns of genetic connectivity in the NZ offshore islands. It illustrated how historical events, such as the last glacial maximum, can shape local genetic diversity, and how this historical pattern can be maintained because of limited contemporary gene exchange. Also, this thesis demonstrated that remote populations could be strongly connected to mainland populations, contributing to the resilience of both systems and confirming the necessity of integrating remote oceanic habitats in the creation of effective Marine Protected Areas (MPA) networks to protect the marine environment.</p>

Studies on Echinoderms of the Southern Pacific Ocean

<p>The collection comprises ten genera (of which one is new) and ten species. Neopsolidium n.g., type species Psolidium convergens (Herouard) has dorsal deposits in the form of small perforated plates up to 0.4 mm in diameter, and cups. The holothurian fauna of southern Chile is generalised, containing few restricted species, and sharing many elements with distant subantarctic islands and with Antaretics.</p>

Studies on Echinoderms of the Southern Pacific Ocean

<p>The collection comprises ten genera (of which one is new) and ten species. Neopsolidium n.g., type species Psolidium convergens (Herouard) has dorsal deposits in the form of small perforated plates up to 0.4 mm in diameter, and cups. The holothurian fauna of southern Chile is generalised, containing few restricted species, and sharing many elements with distant subantarctic islands and with Antaretics.</p>

A southern Māori perspective on stories of Polynesian polar voyaging

As Ngāi Tahu (southern Maori), we take issue with widespread reference in scholarly publication to Polynesian voyagers reaching the Antarctic, an idea that originated in the translation of Rarotongan traditions in the nineteenth century. Analysis of those indicates that they contain no plausible reference to Antarctic seafaring. Southern Māori interests have extended into the Subantarctic Islands for 800 years but there is no reference to Antarctica in our historical traditions. Our archaeology and history document a southern boundary to Māori occupation at Port Ross (Auckland Islands), despite habitable islands existing further south. We think it is very unlikely that Māori or other Polynesian voyaging reached the Antarctic.