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Abstract The world is losing its biodiversity at an alarming rate and many agencies are committing to considerable investment in global conservation. Given the enormity of environmental issues, the funding available to managers is insufficient. Managers must make decisions about how to act within the bounds of this limited funding. Conservation decision-making is also limited by a lack of knowledge about the systems we are trying to conserve. Much of the information required for effective conservation is uncertain. In this thesis I focus on practical ways of approaching the immense predicament of how to make good conservation decisions in the face of these two limitations. In chapter two I provide both an optimal framework and analytic rule of thumb for allocating limited funding among subpopulations of a threatened species. My results show that the number of subpopulations we can effectively manage is driven by the economic constraints placed on management and the risk of extinction of the species we are trying to protect. We discover that it is rarely optimal to manage all the remaining isolated subpopulations of a threatened species. This highlights the importance of a triage approach to the management of subpopulations of a threatened species under the current climate of limited funding, leading us to coin the term ‘subpopulation triage’. One key area of uncertainty that links directly with how we allocate resources for conservation is uncertainty in the impact of our management actions on the systems we are trying to protect (the impact-investment curve). This relationship often drives the outcomes of our decision-making frameworks. In chapter three I investigate how uncertainty in the impact-investment curve, assumed in chapter two, alters our optimal management decision. Again, I find that limited conservation finances are a major limiting factor in the robustness of a strategy to our incomplete understanding. I discover that ‘subpopulation triage’ can be a natural consequence of robust decision-making. Uncertainty is not, however, always beyond our control. We can reduce it by diverting funding from management to collect data on our systems. This entails monitoring costs that must also be considered when making optimal conservation decisions. There are a number of reasons why we could monitor; to reduce our uncertainty in the status of threatened species where management is driven by species status; to aid learning about a component of the system we are managing; for both initial surveillance and adaptive approaches; and to report on the performances of conservation action to stakeholders. In chapter four I assess the benefit of initial surveillance to gain information on biodiversity value before we acquire a land parcel for the reserve network. The risk here is that the land parcel may be removed from the market during surveying. I describe both an optimal method, using stochastic dynamic programming (SDP), and a simple rule of thumb, for how to make such decisions. The solutions to this problem illustrate how optimal conservation is necessarily dynamic and that immediate implementation of a conservation plan may not always yield the best conservation outcome. Learning does not always need to take place in the absence of management. In chapter five I investigate adaptive learning for a threatened species where we must discriminate between multiple hypotheses of how the system works by implementing different management actions. We find that the optimal action depends on our belief in each model being the true model of our system, the benefit from each action under each model, and the number of sites available to implement an active adaptive strategy. In chapter six I investigate when one should learn about the state of the system through monitoring when management is state-dependent. Here our management of subpopulations of a threatened species is based on whether these subpopulations persist. I ask when should we survey or manage a subpopulation, and when, if ever, should we do nothing in a subpopulation of a threatened species. I find that management actions should not only be driven by the return on investment gained by managing a subpopulation but also by our certainty of the persistence of a subpopulation. This is the first work to show a direct trade-off between return on investment from conservation action and reduced uncertainty. One key evaluation method currently adopted worldwide is the use of ‘State of the Environment’ reporting. In chapter seven I assess the flaws of ‘State of the Environment’ reporting, the current method adopted worldwide for evaluating conservation policy. I show the positive biases inherent in such reporting and provide a new metric for reporting on conservation performance that is simple, transparent and provides an unbiased report on performance in reaching conservation objectives. I show that without honest reporting of conservation gains – and losses – we limit our ability to assess where we are in terms of conservation progress. Overall my thesis shows the need for managers to consider a triage approach to threatened species management, not as a process of giving up, but as a tool for ensuring species persistence in light of the urgency of most conservation requirements and the realities of financial and knowledge limitations. Indeed if conservation is a field dedicated to the protection of biodiversity then those responsible for decision-making––politicians, scientists and environmental managers––must use whatever approach gives the best outcome for the environment. Under current limitations, triage is often a necessity not an option.

Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The Superconducting Quantum Interference Device (SQUID) is one of the most sensitive magnetic field sensors in the world. These instruments can only be used optimally for geomagnetic research if placed far from man-made magnetic signals. Moving the SQUID to a remote site leads to several infrastructure-related problems including construction, power, data connectivity, and cryogenic cooling. This thesis investigates possible solutions to these problems and develops guidelines for designing future remote SQUID stations. A remote SQUID observatory typically consists of three structures placed approximately 40 m apart. These include: the control room, which houses all computers and supporting electronics, the power hut, which contains a regulated battery bank charged from a solar array that delivers DC power to the rest of the system, and the SQUID hut itself, which is thermally insulated by cavity walls. The SQUID is placed on an isolation pillar that decouples it from structural vibrations due to wind and outside temperature uctuations. The temperature inside the SQUID hut is also monitored as changes in temperature can result in small deformations of the SQUID mounting system which lead to changes in the SQUID's orientation. The changes in the orientation will appear as slow varying magnetic signals on the SQUID output. In principle, it is possible to compensate for these variations through post-processing. The SQUID needs to be cryogenically cooled to function. The SANSA SQUID is a High Temperature Superconductor (HTS) and operates using liquid nitrogen. Immersion cooling is used, as it is the simplest method, and produces the least amount of mechanical and electrical noise. Over time the liquid nitrogen will evaporate and needs to be replaced without significantly disrupting SQUID operations. A simple yet effective pumping scheme was developed that can transfer approximately 1.8 litres of liquid nitrogen every minute from a refill dewar. Monitoring of the liquid nitrogen level is an important management tool for a remote station, as refilling will be the primary reason for technicians to visit the site. The monitoring is achieved by placing the SQUID dewar on a specially designed non-magnetic load cell scale. The scale has been designed to limit the amount of tilting as the weight changes since this would also change the SQUID orientation. When a HTS SQUID is cooled in a large magnetic field, such as the Earth's field, Abrikosov vortices are likely to form in the superconducting material. As these vortices jump between pinning sites in the material, they increase the 1/f noise of the device and have been found to reduce the stability of the SQUID. Metal shields can be used to reduce the magnetic field, but are awkward to use and also reduce the magnitude of the signals of interest. In this thesis, a shielding method using Helmholtz coils is investigated. These coils are relatively simple and inexpensive to construct and do not attenuate the signals of interest. It was found that by cooling the SQUID in the reduced magnetic field, generated by the Helmholtz coils, the stability of the SQUID can be improved significantly. / AFRIKAANSE OPSOMMING: Die SQUID is die mees sensitiewe magneetveld sensors in die wêreld. Hierdie instrument kan slegs optimaal vir geometriese navorsing gebruik word indien dit ver van mensgemaakte magneetvelde opgestel word. Om die SQUID in 'n afgesonderde area op te stel veroorsaak verskeie probleme met betrekking tot infrastruktuur sover dit konstruksie, kragvoorsiening, en kriogeniese afkoeling aangaan. Hierdie tesis ondersoek moontlike oplossings vir die probleme en riglyne te ontwikkel vir die oprigting van toekomstige SQUID stasies. 'n Tipiese afgele SQUID observatorium bestaan gewoonlik uit 3 strukture wat 40m van mekaar opgestel is. Die beheerkamer bevat al die elektroniese apperaat, die kragkamer bevat 'n stel gereguleerde batterye wat deur sonpanele helaai word en DS krag verskaf aan die stasie en die SQUID-kamer wat deur middel van spoumure teen hitte gensoleer is. Die SQUID word op 'n gesoleerde pilaar geplaas om die invloed van vibrasies a.g.v. wind en wisselende buite temperature te verminder. Die temperatuur binne die SQUID kamer word ook noukeurig gemonitor aangesien wisseling in temperatuur geringe vervorming van die SQUID se montering kan veroorsaak wat 'n verandering van die SQUID se orintasie veroorsaak. Hierdie veranderings sal waargeneem word as stadige varirende sein in die SQUID se lesings. In beginsel is dit moontlik om vir dit te kompenseer deur middel van naprosessering. Die SQUID moet kriogenies afgekoel word om te funksioneer. Die SANSA SQUID is 'n Ho Temperatuur Supergeleier (HTS) en vloeibare stikstof word gebruik vir verkoeling. Afkoeling deur middel van indompeling word gebruik omdat dit die kleinste hoeveelheid meganiese en elektroniese versteuring veroorsaak. Die vloeibare stikstof verdamp mettertyd em moet vervang word sonder om die werking van die SQUID merkbaar te onderbreek. 'n Eenvoudige tog effektiewe oorpompstelsel is ontwikkel wat ongeveer 1.8 liter/minuut vloeibare stikstof vanuit 'n hervullings vakuum es kan oorpomp. Die meting van die vloeibare stikstof vlak is 'n belangrike aspek van die instandhouding van 'n afgele stasie aangesien dit die hoof rede sal wees vir tegnici om die perseel te besoek. Die meting word bewerkstellig deur die plasing van die SQUID se vakuum es op 'n spesiale ontwerpte, nie-magnetiese vrag sel skaal. Hierdie skaal is ontwerp om die mate van kanteling te beperk aangesien dit die orentasie van die SQUID kan benvloed. Wanneer 'n HTS SQUID binne in 'n groot magnetiese veld afgekoel word, is dit waarskynlik dat Abrikosov vortekse in die supergeleidende materiaal sal ontstaan. Soos hierdie vortekse rondspring in die materiaal vermeerder dit die 1/f ruis en daar is gevind dat die stabiliteit van die SQUID nadelig benvloed word. Metaal skilde kan gebruik word om die invloed van die magneetveld te verminder, maar is ongerie ik om te gebruik en verminder ook die sterkte van die seine wat waarneem wil word. In hierdie tesis word Helmholtz spoele ondersoek as 'n afskermings metode. Hierdie spoele is eenvoudig om te vervaardig en verminder nie die sterkte van waarneembare seine nie. Daar is gevind dat die stabiliteit van die SQUID merkbaar verbeter word deur afkoeling in 'n lae magnetiese veld soos bewerkstellig deur die Helmholtz spoele.