This project investigated how kairomone lures, camera traps, and counting software could together contribute to pest management. Images of cumulative daily catch of New Zealand Flower Thrips (NZFT) attracted to a ripe peach lactone (6-pentyl-2H-pyran-2-one; 6-PAP) were automatically loaded to the internet and compared with scanned bases checked weekly using in-house software and manual counting. Camera traps were able to provide thrips counts equivalent to delta traps, but daily and remotely. An 11-fold greater NZFT count occurred within 24 h in passive traps after polyethylene sachets loaded with 250 mg of 6-PAP were placed in trees. Intensive trapping, by placing 1, 2, 4, and 8 traps per tree (500 mg/trap), resulted in a maximum 32-fold increase in thrips per tree. While 6-PAP has proved to be a useful tool for monitoring NZFT numbers, our results suggest that it is not likely to be suitable for mass trapping. Future research should investigate NZFT behavior to better understand population movement on an area-wide basis. Camera traps can be a valuable tool for recording insect flight activity remotely, but the number of traps required for statistically reliable estimates may be prohibitive.

Refuges can be ecologically important, allowing access only to some species or individuals and providing prey protection from predators. Creation of refuges can be used to protect threatened species from introduced predators, which can have large negative impacts that are difficult to attenuate via other means. To design refuges for conservation purposes, refuge accessibility to different species must be understood. Traditional techniques are not adequate to measure or describe complex three-dimensional spaces which are often important refuges. We designed a novel predictive method for modeling threedimensional refuge space using video game software that simulates real-world physics (Unity, PhysX). We use the study system of endemic New Zealand skinks (Oligosoma spp.), their introduced predators, house mice (Mus musculus), and the habitat of interstitial spaces within rock piles to demonstrate how this modeling technique can be used to inform design of habitat enhancement for conservation. We used video game software to model realistic rock piles and measure their interstitial spaces, and found that the spaces we predicted matched those we measured in real rock piles using computed tomography (CT) scanning. We used information about the sizes of gaps accessible to skinks and mice and the results of our modeling to determine the optimal size of rocks to create refuges which would protect skinks from mice. We determined the ideal rock size to be those with graded diameters of 20-40 mm. The approach we developed could be used to describe interstitial spaces in habitats as they naturally occur, or it could be applied to design habitats to benefit particular species.

<p>Worldwide, human development is leading to the expansion and intensification of land use, with increasing encroachment on natural habitats. A rising awareness of the deleterious effects of habitat destruction on species and ecosystems has increased the use of strategies intended to mitigate these negative impacts. One increasingly common strategy is mitigation translocation, the movement of living organisms from a future development site to another location in an effort to mitigate damage caused. Mitigation translocations may be implemented due to legislation or regulations in many jurisdictions, and in many instances command more resources than purely conservation-motivated translocations. Although they are intended to reduce or offset harm, the effectiveness of mitigation translocations as a conservation strategy has been questioned.   I investigated the effectiveness of mitigation translocations for achieving conservation outcomes, using the study system of endemic New Zealand skinks. New Zealand’s skinks show a high level of endemism, are threatened by habitat loss and predation by introduced mammals, and are increasingly subject to mitigation translocations, making them an ideal study system for investigating mitigation outcomes. I investigated: whether mitigation translocations are meeting conservation goals; how the implementation and legal requirements of mitigation translocation relate to conservation goals; and how mitigation translocation practices might be improved to achieve better conservation outcomes.  A technique used in mitigation translocations of lizards in New Zealand is the construction of rock piles as habitat enhancement at the receiving site. I developed a novel use of computer game physics software to model the three-dimensional interstitial spaces within such rock piles, and used this model to design rock piles with the aim of protecting translocated skinks from mice (Mus musculus), New Zealand’s smallest introduced mammalian predator. The protection is achieved by selecting rocks to optimise the size of interstitial spaces to be accessible to skinks but not to the larger mice (or other larger predators). This rock pile design could be used to improve survival of skinks both in translocations and other situations such as backyard conservation or restoration. The modelling technique I developed could be used for investigation of refuge space more widely, for instance in other terrestrial systems or aquatic systems. I also took part in a mitigation translocation of lizards at Transmission Gully near Wellington, New Zealand. I used this translocation to test my rock pile design, and as a case study of the challenges facing mitigation translocations and the barriers to conservation success. In addition, I revisited nine historical mitigation translocations of skinks (7–14 years post translocation), took surveys of current populations to assess their success at meeting conservation goals, and found a success rate of 22%, considerably lower than conservation translocations of New Zealand skinks (success rate of 88.9%). Despite this, all but one met their goals of fulfilling legislative requirements.  Mitigation translocations fail to result in conservation benefit due to their implementation and goals. The goals of mitigation translocations are rooted in legislation, and vary due to inconsistent application of relevant laws (in New Zealand, the Wildlife Act 1953 and the Resource Management Act 1991), and the fact that the requirements under these laws do not necessarily reflect conservation goals. Additionally, mitigation translocations may be undertaken even when evidence indicates that meaningful conservation outcomes are unlikely (as in the case of the translocation at Transmission Gully). Failure may also be due to poor implementation; examples from case studies here include failure to control predators, low standards of planting at receptor sites, and small founder populations. To improve conservation outcomes, legal requirements for mitigation translocations should be implemented to require biologically-relevant goals (including a no net loss of biodiversity standard) and management techniques, and alternative methods of meeting conservation goals should be considered where appropriate.</p>

© 2021 The Authors. Refuges can be ecologically important, allowing access only to some species or individuals and providing prey protection from predators. Creation of refuges can be used to protect threatened species from introduced predators, which can have large negative impacts that are difficult to attenuate via other means. To design refuges for conservation purposes, refuge accessibility to different species must be understood. Traditional techniques are not adequate to measure or describe complex three-dimensional spaces which are often important refuges. We designed a novel predictive method for modeling three-dimensional refuge space using video game software that simulates real-world physics (Unity, PhysX). We use the study system of endemic New Zealand skinks (Oligosoma spp.), their introduced predators, house mice (Mus musculus), and the habitat of interstitial spaces within rock piles to demonstrate how this modeling technique can be used to inform design of habitat enhancement for conservation. We used video game software to model realistic rock piles and measure their interstitial spaces, and found that the spaces we predicted matched those we measured in real rock piles using computed tomography (CT) scanning. We used information about the sizes of gaps accessible to skinks and mice and the results of our modeling to determine the optimal size of rocks to create refuges which would protect skinks from mice. We determined the ideal rock size to be those with graded diameters of 20–40 mm. The approach we developed could be used to describe interstitial spaces in habitats as they naturally occur, or it could be applied to design habitats to benefit particular species.

<p>Worldwide, human development is leading to the expansion and intensification of land use, with increasing encroachment on natural habitats. A rising awareness of the deleterious effects of habitat destruction on species and ecosystems has increased the use of strategies intended to mitigate these negative impacts. One increasingly common strategy is mitigation translocation, the movement of living organisms from a future development site to another location in an effort to mitigate damage caused. Mitigation translocations may be implemented due to legislation or regulations in many jurisdictions, and in many instances command more resources than purely conservation-motivated translocations. Although they are intended to reduce or offset harm, the effectiveness of mitigation translocations as a conservation strategy has been questioned.   I investigated the effectiveness of mitigation translocations for achieving conservation outcomes, using the study system of endemic New Zealand skinks. New Zealand’s skinks show a high level of endemism, are threatened by habitat loss and predation by introduced mammals, and are increasingly subject to mitigation translocations, making them an ideal study system for investigating mitigation outcomes. I investigated: whether mitigation translocations are meeting conservation goals; how the implementation and legal requirements of mitigation translocation relate to conservation goals; and how mitigation translocation practices might be improved to achieve better conservation outcomes.  A technique used in mitigation translocations of lizards in New Zealand is the construction of rock piles as habitat enhancement at the receiving site. I developed a novel use of computer game physics software to model the three-dimensional interstitial spaces within such rock piles, and used this model to design rock piles with the aim of protecting translocated skinks from mice (Mus musculus), New Zealand’s smallest introduced mammalian predator. The protection is achieved by selecting rocks to optimise the size of interstitial spaces to be accessible to skinks but not to the larger mice (or other larger predators). This rock pile design could be used to improve survival of skinks both in translocations and other situations such as backyard conservation or restoration. The modelling technique I developed could be used for investigation of refuge space more widely, for instance in other terrestrial systems or aquatic systems. I also took part in a mitigation translocation of lizards at Transmission Gully near Wellington, New Zealand. I used this translocation to test my rock pile design, and as a case study of the challenges facing mitigation translocations and the barriers to conservation success. In addition, I revisited nine historical mitigation translocations of skinks (7–14 years post translocation), took surveys of current populations to assess their success at meeting conservation goals, and found a success rate of 22%, considerably lower than conservation translocations of New Zealand skinks (success rate of 88.9%). Despite this, all but one met their goals of fulfilling legislative requirements.  Mitigation translocations fail to result in conservation benefit due to their implementation and goals. The goals of mitigation translocations are rooted in legislation, and vary due to inconsistent application of relevant laws (in New Zealand, the Wildlife Act 1953 and the Resource Management Act 1991), and the fact that the requirements under these laws do not necessarily reflect conservation goals. Additionally, mitigation translocations may be undertaken even when evidence indicates that meaningful conservation outcomes are unlikely (as in the case of the translocation at Transmission Gully). Failure may also be due to poor implementation; examples from case studies here include failure to control predators, low standards of planting at receptor sites, and small founder populations. To improve conservation outcomes, legal requirements for mitigation translocations should be implemented to require biologically-relevant goals (including a no net loss of biodiversity standard) and management techniques, and alternative methods of meeting conservation goals should be considered where appropriate.</p>