title: Genetic diversity and potential responses of New Zealand Rotifera and Antarctic Collembola to environmental changes

authors: Collins, Gemma Elyse

subjects: Mitochondrial DNA

abstract: Environmental changes can impact the diversity and abundance of biotic communities as well as their dispersal among geographic regions. The availability of sensitive molecular techniques has enabled assessments of diversity at levels previously unattainable and allowed investigation of how biota are influenced by their environment. This thesis examines the use of mitochondrial DNA sequence variation in New Zealand freshwater rotifers (Rotifera) and Antarctic springtails (Collembola) to assess diversity and determine responses to environmental changes.
 
Using mitochondrial cytochrome c oxidase subunit I (COI) DNA sequences, I examined the diversity of New Zealand rotifers. The rotifer phylum is comprised of a variety of species and individuals are often abundant in freshwater systems globally. Species are associated with specific trophic states and in New Zealand are routinely monitored as biological indicators of ecosystem health. At present, species’ identification relies on morphological characters which is time consuming and requires appropriate taxonomic expertise. Here, I assessed the use of COI sequences as an alternative for the routine identification of New Zealand rotifers. A total of 177 individuals were sequenced from 45 morphologically-recognised taxa. High intraspecific variation was found among 14 species (3.4 - 39.0% divergence) and based on comparisons with sequences available on GenBank, 18 species were genetically distinct from their global conspecifics (>6.6% divergence). I conclude that these distinct haplotypes are potentially endemic among putatively cosmopolitan species. A better understanding of rotifer diversity in New Zealand will allow the detection and potential control of future non-indigenous species’ incursions. 

In order to assess the effects of environmental temperature changes on the genetic structure of populations, I examined the diversity of COI sequences of Antarctic springtails relative to the environmental conditions during which they were active. The target species, Gomphiocephalus hodgsoni, is known to harbour high genetic (COI) diversity as well as having considerable variation in their ability to tolerate sub-zero temperature – specifically, there appear to be “warm” and “cold” adapted individuals. I sequenced 151 individuals collected in pitfall traps near Spaulding Pond, Taylor Valley and found 19 unique COI haplotypes that separated into two distinct groups (1.6% divergence), with one haplotype group comprising 80% of the sequenced population. During two-hourly sampling, air temperature was the strongest predictor of activity between the two haplotype groups (R2 = 0.56) and when combined with subsurface soil temperature, relative humidity and photosynthetically active radiation, explanatory power increased to R2 = 0.71. Air temperatures are predicted to continue increasing across most of Antarctica which is expected to impact springtails by a detectable amount. Monitoring programmes focussed on the temporal and spatial changes in COI haplotype diversity may provide a sensitive measure of population responses to climate change. 

Collectively, these two studies contribute baseline data of the current genetic diversity and population structure among New Zealand rotifers and Antarctic springtails and provide a platform by which to monitor future environmental changes.

text: Genetic diversity and potential responses of New Zealand Rotifera and Antarctic Collembola to environmental changes Environmental changes can impact the diversity and abundance of biotic communities as well as their dispersal among geographic regions. The availability of sensitive molecular techniques has enabled assessments of diversity at levels previously unattainable and allowed investigation of how biota are influenced by their environment. This thesis examines the use of mitochondrial DNA sequence variation in New Zealand freshwater rotifers (Rotifera) and Antarctic springtails (Collembola) to assess diversity and determine responses to environmental changes.
 
Using mitochondrial cytochrome c oxidase subunit I (COI) DNA sequences, I examined the diversity of New Zealand rotifers. The rotifer phylum is comprised of a variety of species and individuals are often abundant in freshwater systems globally. Species are associated with specific trophic states and in New Zealand are routinely monitored as biological indicators of ecosystem health. At present, species’ identification relies on morphological characters which is time consuming and requires appropriate taxonomic expertise. Here, I assessed the use of COI sequences as an alternative for the routine identification of New Zealand rotifers. A total of 177 individuals were sequenced from 45 morphologically-recognised taxa. High intraspecific variation was found among 14 species (3.4 - 39.0% divergence) and based on comparisons with sequences available on GenBank, 18 species were genetically distinct from their global conspecifics (>6.6% divergence). I conclude that these distinct haplotypes are potentially endemic among putatively cosmopolitan species. A better understanding of rotifer diversity in New Zealand will allow the detection and potential control of future non-indigenous species’ incursions. 

In order to assess the effects of environmental temperature changes on the genetic structure of populations, I examined the diversity of COI sequences of Antarctic springtails relative to the environmental conditions during which they were active. The target species, Gomphiocephalus hodgsoni, is known to harbour high genetic (COI) diversity as well as having considerable variation in their ability to tolerate sub-zero temperature – specifically, there appear to be “warm” and “cold” adapted individuals. I sequenced 151 individuals collected in pitfall traps near Spaulding Pond, Taylor Valley and found 19 unique COI haplotypes that separated into two distinct groups (1.6% divergence), with one haplotype group comprising 80% of the sequenced population. During two-hourly sampling, air temperature was the strongest predictor of activity between the two haplotype groups (R2 = 0.56) and when combined with subsurface soil temperature, relative humidity and photosynthetically active radiation, explanatory power increased to R2 = 0.71. Air temperatures are predicted to continue increasing across most of Antarctica which is expected to impact springtails by a detectable amount. Monitoring programmes focussed on the temporal and spatial changes in COI haplotype diversity may provide a sensitive measure of population responses to climate change. 

Collectively, these two studies contribute baseline data of the current genetic diversity and population structure among New Zealand rotifers and Antarctic springtails and provide a platform by which to monitor future environmental changes.

year: 2015

title: International Terrorism: response and justifications

authors: Smith, Ron C.

subjects: terrorism

abstract: Old habits die hard and nowhere is this more evident than in talk about terrorism. For many this is still an incorrigibly contested concept, and thus the word and its cognates still tend to be used exactly as a particular speaker or writer may choose. This is clearly a state of affairs that hobbles rational debate. If we are effectively to deal with the problem of terrorism (and especially international terrorism) we must accept a clear definition of the concept and stop hiding behind arbitrary and self-serving usages. This should not be a difficult project since the United Nations has already sent out a conceptual framework and begun filling in the detail. Of course, this is only the first stage in combination terrorism. The second is to amend the behaviour of states so that they no longer support such activities. For this to be effective it may be this strict measures will be required.

text: International Terrorism: response and justifications Old habits die hard and nowhere is this more evident than in talk about terrorism. For many this is still an incorrigibly contested concept, and thus the word and its cognates still tend to be used exactly as a particular speaker or writer may choose. This is clearly a state of affairs that hobbles rational debate. If we are effectively to deal with the problem of terrorism (and especially international terrorism) we must accept a clear definition of the concept and stop hiding behind arbitrary and self-serving usages. This should not be a difficult project since the United Nations has already sent out a conceptual framework and begun filling in the detail. Of course, this is only the first stage in combination terrorism. The second is to amend the behaviour of states so that they no longer support such activities. For this to be effective it may be this strict measures will be required.

year: 2002

title: Walking into the past to explore the future: Utulizing larval densities to measure the effects of two climate change factors, temperature and salinity on Poorohe (common smelt, Retropinna retropinna) abundance in Te Puuaha o Waikato

authors: Robcke, Sidney

subjects: Common smelt

abstract: Poorohe (common smelt, Retropinna retropinna) are a highly valued kai species in Te Puuaha o Waikato (the lower 66 km of the Waikato River). Fisher whaanau have observed changes in the amount Poorohe that are harvested during annual fish harvests. Since Poorohe are particularly vulnerable to environmental changes, whaanau are particularly concerned about the how climate change might impact Poorohe populations. Climate change vulnerability assessments (CCVA) currently exist for several native New Zealand fish freshwater species; however, one does not yet exist for Poorohe. Previous larval distribution studies in the lower Waikato River only sampled as far downstream as Tuakau bridge (approximately 45km from the river mouth). These studies indicated that important spawning habitats likely existed downstream of Tuakau bridge. Temperature increases and saltwater intrusion have been identified as two climate change factors that will likely impact Poorohe in Te Puuaha o Waikato, because ambient temperatures have increased since the industrial revolution and the proximity of the study area to the ocean. A literature review was used to explore the experiences of fisher whaanau through the past, present and how the experiences will continue to change in a changing climate. The effects of temperature and saltwater intrusion on Poorohe populations were explored through replicating the methods of past research carried out in the 1980s and 2010s. Current river temperatures are in the optimal temperature range (12°C - 18°C) for Poorohe spawning. The saltwater wedge was suppressed by the high river flow during the eight-week sampling period, and it is unclear whether saltwater intrusion has an impact on Poorohe spawning. Larval densities did not significantly increase down river, which suggests large spawning habitat is not found downstream of Tuakau bridge. Furthermore, there were no decreases in larval densities in the two saltwater sites. This study has contributed to the available literature necessary to develop a CCVA for Poorohe and explored the cultural heritage of traditionally significant practices in Te Puuaha o Waikato relating to Poorohe.

text: Walking into the past to explore the future: Utulizing larval densities to measure the effects of two climate change factors, temperature and salinity on Poorohe (common smelt, Retropinna retropinna) abundance in Te Puuaha o Waikato Poorohe (common smelt, Retropinna retropinna) are a highly valued kai species in Te Puuaha o Waikato (the lower 66 km of the Waikato River). Fisher whaanau have observed changes in the amount Poorohe that are harvested during annual fish harvests. Since Poorohe are particularly vulnerable to environmental changes, whaanau are particularly concerned about the how climate change might impact Poorohe populations. Climate change vulnerability assessments (CCVA) currently exist for several native New Zealand fish freshwater species; however, one does not yet exist for Poorohe. Previous larval distribution studies in the lower Waikato River only sampled as far downstream as Tuakau bridge (approximately 45km from the river mouth). These studies indicated that important spawning habitats likely existed downstream of Tuakau bridge. Temperature increases and saltwater intrusion have been identified as two climate change factors that will likely impact Poorohe in Te Puuaha o Waikato, because ambient temperatures have increased since the industrial revolution and the proximity of the study area to the ocean. A literature review was used to explore the experiences of fisher whaanau through the past, present and how the experiences will continue to change in a changing climate. The effects of temperature and saltwater intrusion on Poorohe populations were explored through replicating the methods of past research carried out in the 1980s and 2010s. Current river temperatures are in the optimal temperature range (12°C - 18°C) for Poorohe spawning. The saltwater wedge was suppressed by the high river flow during the eight-week sampling period, and it is unclear whether saltwater intrusion has an impact on Poorohe spawning. Larval densities did not significantly increase down river, which suggests large spawning habitat is not found downstream of Tuakau bridge. Furthermore, there were no decreases in larval densities in the two saltwater sites. This study has contributed to the available literature necessary to develop a CCVA for Poorohe and explored the cultural heritage of traditionally significant practices in Te Puuaha o Waikato relating to Poorohe.

year: 2024-11-23