title: Do long-tailed bats alter their evening activity in response to aircraft noise?

authors: Le Roux, Darren Shaun

subjects: aircraft activity

abstract: Human-generated noise may alter animal activity patterns and mask vocal signals. We used field-based observations and a playback experiment to investigate whether aircraft activity and noise alter the evening activity of New Zealand long-tailed bats (Chalinolobus tuberculatus) a cryptic threatened species. Low-altitude aircraft activity temporally overlapped bat activity near the runway of an international airport, but was unlikely to mask echolocation pulses as aircraft noise was most intense at ≤ 10 kHz. There was no statistically significant difference in mean bat activity during and after overflights compared with pre-aircraft activity. The experiment revealed that playback stimuli (aircraft passes and two controls: silent tracks and blackbird (Turdus merula) calls) differed in their effect on bat activity at two sites, one with low and one with high aircraft activity. Simulated aircraft noise and silent tracks reduced bat activity when compared with blackbird calls (P < 0.05). Bats may have found it easier to detect observers during the playback of silent tracks (sampling involved walking circuits with hand-held detectors), and may have reduced activity to a perceived threat. This result suggests that broadcasted aircraft noise is no more disturbing than researcher presence during playback trials. Evidence for a site × playback stimuli interaction (P = 0.054) suggests that bats at the site with high aircraft activity may have habituated to aircraft noise. Both correlative and experimental data suggests that aircraft activity and noise may not have major impacts on long-tailed bat activity.

text: Do long-tailed bats alter their evening activity in response to aircraft noise? Human-generated noise may alter animal activity patterns and mask vocal signals. We used field-based observations and a playback experiment to investigate whether aircraft activity and noise alter the evening activity of New Zealand long-tailed bats (Chalinolobus tuberculatus) a cryptic threatened species. Low-altitude aircraft activity temporally overlapped bat activity near the runway of an international airport, but was unlikely to mask echolocation pulses as aircraft noise was most intense at ≤ 10 kHz. There was no statistically significant difference in mean bat activity during and after overflights compared with pre-aircraft activity. The experiment revealed that playback stimuli (aircraft passes and two controls: silent tracks and blackbird (Turdus merula) calls) differed in their effect on bat activity at two sites, one with low and one with high aircraft activity. Simulated aircraft noise and silent tracks reduced bat activity when compared with blackbird calls (P < 0.05). Bats may have found it easier to detect observers during the playback of silent tracks (sampling involved walking circuits with hand-held detectors), and may have reduced activity to a perceived threat. This result suggests that broadcasted aircraft noise is no more disturbing than researcher presence during playback trials. Evidence for a site × playback stimuli interaction (P = 0.054) suggests that bats at the site with high aircraft activity may have habituated to aircraft noise. Both correlative and experimental data suggests that aircraft activity and noise may not have major impacts on long-tailed bat activity.

year: 2012

title: Vulnerability of traditional beef sector to drought and the challenges of climate change: The case of Kgatleng District, Botswana

authors: Masike, Sennye

subjects: cattle sector

abstract: Cattle’s rearing in Botswana is undertaken in two sectors: the communal and commercial. The communal sector is exclusively free range and therefore depends on biomass production. This makes the systems highly susceptible to drought. One strategy that has been devised by farmers to adapt to drought has been to overstock. However, this strategy may not be the best adaptation strategy as it leads to overgrazing and quick depletion of scarce biomass during the drought years. Climate change may increase the vulnerability of the communal cattle sector in the country mostly through changes and variability of rainfall. In the article, we determine the reliability of the rainfall in the Khurutshe area, Botswana. Vulnerability of the cattle sector to system severe failure is also determined. Lastly, the effects of climate change on return period of drought are investigated. Results indicate that the reliability index of rainfall in the Kgatleng District is 0.5. The vulnerability index of the cattle is estimated at 8000 per year. Lastly, using SimCLIM computer model climate change will shorten the return period of mild drought from 2 years to 1.6 years by 2050. These findings have serious implications on the recovery period of the cattle to withstand the next drought period.

text: Vulnerability of traditional beef sector to drought and the challenges of climate change: The case of Kgatleng District, Botswana Cattle’s rearing in Botswana is undertaken in two sectors: the communal and commercial. The communal sector is exclusively free range and therefore depends on biomass production. This makes the systems highly susceptible to drought. One strategy that has been devised by farmers to adapt to drought has been to overstock. However, this strategy may not be the best adaptation strategy as it leads to overgrazing and quick depletion of scarce biomass during the drought years. Climate change may increase the vulnerability of the communal cattle sector in the country mostly through changes and variability of rainfall. In the article, we determine the reliability of the rainfall in the Khurutshe area, Botswana. Vulnerability of the cattle sector to system severe failure is also determined. Lastly, the effects of climate change on return period of drought are investigated. Results indicate that the reliability index of rainfall in the Kgatleng District is 0.5. The vulnerability index of the cattle is estimated at 8000 per year. Lastly, using SimCLIM computer model climate change will shorten the return period of mild drought from 2 years to 1.6 years by 2050. These findings have serious implications on the recovery period of the cattle to withstand the next drought period.

year: 2008-03

title: Understanding the potential exposure of coastal marae and urupā in Aotearoa New Zealand to sea level rise

authors: Bailey-Winiata, Akuhata Patrick Stephen

subjects: Marae

abstract: In Aotearoa New Zealand, Māori are Indigenous and have inhabited these islands for the past 700 years. They have an intricate physical and spiritual connection to places and the environment. This is reflected in the Māori creation story, where Ranginui (sky father) and Papatūānuku (Earth mother) are the ancestral parents of Māori. Between these two gods is the marae, the Māori meeting house. Marae are where the domestic life of Māori traditionally ran its course, with marae being an overarching term to illustrate multiple buildings which each have a specific role to play within the community. Often, marae have an associated urupā (burial ground). Historically, marae and their associated urupā are positioned along the low-lying coast, providing easy access to kaimoana (sea food), transport and trade. However, coastal marae and urupā are at an increasing threat of inundation and erosion from sea level rise, and will also be impacted by other effects of climate change such as drought and other changes to weather patterns such as storms.
Many coastal marae and urupā are already experiencing the impacts of coastal flooding and erosion, however, little is known about the exposure of coastal marae and urupā to sea level rise nationally. Therefore, the main aim of this thesis is to explore the potential exposure of coastal marae nationally, with a particular focus on the Bay of Plenty coastal marae including coastal urupā. This aim was achieved by addressing three objectives. The first of which was to investigate the potential national exposure of coastal marae to a 100 year annual recurrence interval extreme sea level event, with the addition of sea level rise. Second, I conducted a nationally-focused assessment of the local coastal geomorphology surrounding coastal marae to determine the potential response of the coast to sea level rise. I also undertook a case study on the BOP which included a more detailed assessment of the geomorphology around the coastal marae and urupā in this region. Third, findings from these two objectives are brought together to consider the next steps to determine how to move forward with planning to manage coastal marae and urupā with sea level rise.
A spatial mapping approach using Arc GIS and existing datasets was used to address these aims, combining the Coastlines and Islands polygon, marae and urupā locational data and the Aotearoa New Zealand coastal hydrosystem classification system proposed by Hume in 2016. This showed that 191 marae around Aotearoa New Zealand are within 1 km of the coast and in the Bay of Plenty 41 urupā are within 1 km. I then used the bathtub modelling approach to get a national first-pass assessment of the potential exposure of these marae and urupā to a 100 year extreme sea level event at current mean sea level, with 10 cm increments of sea level rise up to 3 m. Six coastal marae were potentially exposed to a 100 year extreme sea level event at current mean sea level, with 41 coastal marae are potentially exposed to a 100 year extreme sea level event with a 3 m rise in mean sea level. The most common type of coastal geomorphology nationally and in the Bay of Plenty was shallow drowned valleys, with 72 coastal marae in this category. The response of these systems to sea level rise manifests as changes in the tidal regime and sediment transport dynamics which will affect inundation and erosion of low-lying areas, where many coastal marae and urupā are positioned.
Thus, it is clear that marae and urupā are nationally at risk to sea level rise, and their responses will be highly variable with geomorphology. But what are the next steps? There are many legislative documents such as the coastal climate change and hazards report by the Ministry for the Environment which suggests that the Dynamic Adaptive Policy Pathways strategy to address the uncertainty surrounding climate change, recommended as a method for future planning. Another is the pending reform of the Resource Management Act which will introduce a climate change adaptation act where support for managed retreat will be made available. However, any management strategies for marae, hapū and iwi will need to be cognisant of the tapū and māna that these places hold, and there will be no one size fits all approach.

text: Understanding the potential exposure of coastal marae and urupā in Aotearoa New Zealand to sea level rise In Aotearoa New Zealand, Māori are Indigenous and have inhabited these islands for the past 700 years. They have an intricate physical and spiritual connection to places and the environment. This is reflected in the Māori creation story, where Ranginui (sky father) and Papatūānuku (Earth mother) are the ancestral parents of Māori. Between these two gods is the marae, the Māori meeting house. Marae are where the domestic life of Māori traditionally ran its course, with marae being an overarching term to illustrate multiple buildings which each have a specific role to play within the community. Often, marae have an associated urupā (burial ground). Historically, marae and their associated urupā are positioned along the low-lying coast, providing easy access to kaimoana (sea food), transport and trade. However, coastal marae and urupā are at an increasing threat of inundation and erosion from sea level rise, and will also be impacted by other effects of climate change such as drought and other changes to weather patterns such as storms.
Many coastal marae and urupā are already experiencing the impacts of coastal flooding and erosion, however, little is known about the exposure of coastal marae and urupā to sea level rise nationally. Therefore, the main aim of this thesis is to explore the potential exposure of coastal marae nationally, with a particular focus on the Bay of Plenty coastal marae including coastal urupā. This aim was achieved by addressing three objectives. The first of which was to investigate the potential national exposure of coastal marae to a 100 year annual recurrence interval extreme sea level event, with the addition of sea level rise. Second, I conducted a nationally-focused assessment of the local coastal geomorphology surrounding coastal marae to determine the potential response of the coast to sea level rise. I also undertook a case study on the BOP which included a more detailed assessment of the geomorphology around the coastal marae and urupā in this region. Third, findings from these two objectives are brought together to consider the next steps to determine how to move forward with planning to manage coastal marae and urupā with sea level rise.
A spatial mapping approach using Arc GIS and existing datasets was used to address these aims, combining the Coastlines and Islands polygon, marae and urupā locational data and the Aotearoa New Zealand coastal hydrosystem classification system proposed by Hume in 2016. This showed that 191 marae around Aotearoa New Zealand are within 1 km of the coast and in the Bay of Plenty 41 urupā are within 1 km. I then used the bathtub modelling approach to get a national first-pass assessment of the potential exposure of these marae and urupā to a 100 year extreme sea level event at current mean sea level, with 10 cm increments of sea level rise up to 3 m. Six coastal marae were potentially exposed to a 100 year extreme sea level event at current mean sea level, with 41 coastal marae are potentially exposed to a 100 year extreme sea level event with a 3 m rise in mean sea level. The most common type of coastal geomorphology nationally and in the Bay of Plenty was shallow drowned valleys, with 72 coastal marae in this category. The response of these systems to sea level rise manifests as changes in the tidal regime and sediment transport dynamics which will affect inundation and erosion of low-lying areas, where many coastal marae and urupā are positioned.
Thus, it is clear that marae and urupā are nationally at risk to sea level rise, and their responses will be highly variable with geomorphology. But what are the next steps? There are many legislative documents such as the coastal climate change and hazards report by the Ministry for the Environment which suggests that the Dynamic Adaptive Policy Pathways strategy to address the uncertainty surrounding climate change, recommended as a method for future planning. Another is the pending reform of the Resource Management Act which will introduce a climate change adaptation act where support for managed retreat will be made available. However, any management strategies for marae, hapū and iwi will need to be cognisant of the tapū and māna that these places hold, and there will be no one size fits all approach.

year: 2021