Advancing land-sea conservation planning: cross-system threats and competing values

Álvarez Romero, Jorge G. (2012) Advancing land-sea conservation planning: cross-system threats and competing values. PhD thesis, James Cook University.

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Overfishing, pollution, coastal development and climate change threaten marine biodiversity globally and compromise the services that marine ecosystems provide. Spatial management, including setting aside land for conservation, is central to curbing the global decline in biodiversity, but many threats originate from beyond the boundaries of protected areas. This is a particular problem in marine systems, which are influenced by many activities on land. Integrating land and sea conservation planning is therefore of utmost importance. Systematic conservation planning (SCP) provides a framework to identify areas where actions can be effective in addressing these threats, while minimising the costs of interventions. Methodologies to incorporate land-sea connections in conservation planning are developing quickly, but most conservation planning initiatives have not embraced an integrated approach. Recent advances in theories and tools in conservation planning can contribute to overcoming these limitations and explicitly incorporating land-sea connections. However, additional scientific knowledge is needed to address cross-system threats and to manage the complexities of conservation across realms.

The goal of my thesis is to improve understanding of fundamental elements in land-sea conservation planning and investigate how these can be incorporated into the planning process. More specifically, my project explores theoretical and methodological aspects of two decision-making problems associated with a land-sea approach: integrating cross system-threats (especially considering how land-based threats can affect marine and coastal spatial prioritisation), and considering competing values (i.e., spatial incongruence between terrestrial (upstream) and marine (downstream) values of coastal catchments). Three objectives bound the scope of my thesis: (1) to assess progress in land-sea planning theory and practice, and identify key elements to achieve land-sea integration, and the challenges thereof (Chapters 2 and 3); (2) to develop novel methods for incorporating cross-system threats, especially mapping and targeting land-based threats (Chapters 4 and 5); and (3) to explore coincidence between land values derived from terrestrial and marine conservation objectives (Chapter 6).

In order to address these objectives, first I reviewed the literature describing connections between land and sea, and how they have been incorporated into conservation planning (Chapter 2). Key results of this chapter include: a classification of land-sea processes, which also identifies potential planning strategies (design criteria, variable objectives, planning units, and movable areas) to incorporate these processes into planning. I also identified major cross-system threats and elements that planners should consider (sources, affected realms, directionality of influence, stressors, and areas for intervention). The main output of this chapter is an operational framework to guide land-sea planning informed by expert opinion and case studies that considered land-sea connections.

I then analysed marine planning initiatives in the Gulf of California (GoC) to investigate whether the elements identified in the framework have informed practical applications (Chapter 3). The GoC is an ideal case study for comparing areas identified as priorities in multiple marine conservation plans, with seven marine planning exercises undertaken in the past 15 years. Despite some convergence, I found important spatial differences in priorities between plans. The existence of multiple marine conservation plans in the GoC highlighted some of the complexities and benefits of having multiple sets of priorities. I also showed that the use of SCP methods has progressed slowly and I highlighted benefits and difficulties of applying SCP principles and tools.

A major gap in marine management of the GoC is the need to address land-sea connections, particularly land-based pollution which has been identified as a key threat to marine ecosystems. I used catchment modelling to assess the magnitude of the problem and to identify areas that require intervention for mitigation of land-based threats (Chapter 4). Different catchment modelling approaches to identify sources of nutrients and sediments vary in data requirements, outputs, and applications. I compared two catchment models commonly used to target catchment management (N-SPECT and SedNet) in terms of their approach (method and assumptions), data requirements (availability and preparation), performance (differences between modelled and observed runoff and suspended sediment loads), and outputs (similarity in spatial pattern of pollutant supply and end-of-river loads). I found that both models are generally applicable under limited data circumstances, but SedNet requires additional datasets and parameters. The patterns of supply are similar and outputs of both models are adequate for prioritising long-term management in land-sea planning applications. However, the lower performance of N-SPECT limits its application for plume and ecological modelling. Additional functionality in SedNet offers useful outputs for targeting catchment management. This includes accounting for the effects of reservoir trapping of suspended sediment.

In addition to mapping sources of land-based pollution, identifying the affected areas and the scale of influence on marine ecosystems is critical to assess the ecological impacts of degraded water quality. I developed an improved model of exposure to river plumes (based on satellite imagery) to assess the potential impact of land-based pollution, using the Great Barrier Reef (Australia) as a case study (Chapter 5). To build the model, first I mapped plumes and identified surface water (colour) classes using maximum-likelihood classification of enhanced satellite images. Second, I summarised weekly data and calculated annual frequency of plume occurrence and mean colour class values. Third, I calculated the proportional contribution of major rivers to the regional total suspended sediment (TSS) and dissolved inorganic nitrogen (DIN) loads. Following that step, I scaled the proportional contributions with a cost-distance function (known plume extents, peak flows and mean colour class). Finally, I calculated exposure by combining scaled contributions and frequency of occurrence. I then used the exposure model to quantify the extent of each exposure category (TSS/DIN) and the affected area of coral reefs and seagrass beds. I found that classification of true colour satellite images can be used to map plumes and to qualitatively assess exposure to river-borne pollutants. The model I developed is useful to study the spatial and temporal variation in exposure of coastal-marine ecosystems to riverine plumes. The observed inter-annual variation in exposure of habitats to pollutants stresses the need to incorporate the temporal component in exposure and risk models.

In Chapter 6, I used the outputs from the catchment model and a river plume models to develop an integrated land-sea plan for selected catchments in the GoC. I used the catchment model to map sources and loads of selected pollutants (TSS and TN). I also used a land use change model to calculate the probability of change to anthropic land use classes and the vulnerability of natural vegetation to clearing. Based on these two outputs, and the link between pollutant sources (catchments) and the affected marine areas (of varying conservation priority), I set two types of objectives to prioritise management of land areas: biodiversity conservation (protection of vertebrates and vegetation types, and aimed to target areas with a higher vulnerability to be converted into anthropic areas) and water quality objectives for catchment management (based on contribution to pollutant loads, vulnerability to clearing, magnitude of change from natural conditions and link to marine priority conservation areas). My results emphasise that integrating land use change in spatial prioritisation procedures is needed to better inform management for terrestrial conservation and water quality. Integrating catchment and river plume models is thus critical to assessing effectiveness of management actions to achieve water quality objectives.

In summary, my thesis advances conservation planning in five ways: (1) through the proposal of an operational framework that identifies and integrates elements crucial to integrated land-sea conservation planning; (2) by providing insights into convergence of priorities derived from different planning approaches and benefits and difficulties of having multiple sets of plans; (3) by identifying key factors influencing the selection of catchment models for regional land-sea planning applications; (4) by developing an improved plume exposure model to inform catchment management and design of MPA networks; and (5) by providing a method for integrating catchment, land use change and plume models for land-sea planning applications.

Item ID: 27690
Item Type: Thesis (PhD)
Keywords: marine conservation; biodiversity; conservation threats; marine protected areas; land-sea conservation; marine ecosystems; coastal ecosystems; coastal conservation; conservation planning; Gulf of California; river plumes; surface water; runoff; Great Barrier Reef; GBR; sediments; coastal sediments
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Publications arising from this thesis are available from the Related URLs field. The publications are:

Álvarez Romero, Jorge, Pressey, Robert L., Ban, Natalie C., Vance-Borland, Ken, Willer, Chuck, Klein, Carissa Joy, and Gaines, Steven D. (2011) Integrated land-sea conservation planning: the missing links. Annual Review of Ecology, Evolution, and Systematics, 42. pp. 381-409.

Álvarez-Romero, Jorge, Pressey, Robert L., Ban, Natalie C., Torre-Cosio, Jorge, and Aburto-Oropeza, Octavio (2013) Marine conservation planning in practice: lessons learned from the Gulf of California. Aquatic Conservation: marine and freshwater ecosystems , 23 (4). pp. 483-505.

Álvarez-Romero, Jorge G., Devlin, Michelle, da Silva, Eduardo Teixeira, Petus, Caroline, Ban, Natalie C., Pressey, Robert L., Kool, Johnathan, Roberts, Jason J., Cerdeira-Estrada, Sergio, Wenger, Amelia S., and Brodie, Jon (2013) A novel approach to model exposure of coastal-marine ecosystems to riverine flood plumes based on remote sensing techniques. Journal of Environmental Management, 119. pp. 194-207.

Devlin, M.J., McKinna, L.W., Álvarez-Romero, J.G., Petus, C., Abott, B., Harkness, P., and Brodie, J. (2012) Mapping the pollutants in surface riverine flood plume waters in the Great Barrier Reef, Australia. Marine Pollution Bulletin, 65 (4-9). pp. 224-235.

Bainbridge, Zoe T., Wolanski, Eric, Álvarez Romero, Jorge, Lewis, Stephen E., and Brodie, Jon E. (2012) Fine sediment and nutrient dynamics related to particle size and floc formation in a Burdekin River flood plume, Australia. Marine Pollution Bulletin, 65 (4-9). pp. 236-248.

Devlin, Michelle, Wenger, Amelia, Da Silva, Eduardo, Álvarez Romero, Jorge G., Waterhouse, Jane, and McKenzie, Len (2012) Extreme weather conditions in the Great Barrier Reef: drivers of change? In: Proceedings of the 12th International Coral Reef Symposium, pp. 1-5. From: 12th International Coral Reef Symposium, 9-13 July 2012, Cairns, QLD, Australia.

Ban, Natalie C., Januchowski-Hartley, Stephanie, Álvarez-Romero, Jorge, Mills, Morena, Pressey, Robert L., Linke, Simon, and de Freitas, Debora (2013) Marine and freshwater conservation planning: from representation to persistence. In: Craighead, F. Lance, and Convis, Charles L., (eds.) Conservation Planning: shaping the future. Esri Press, Redlands, CA, USA, pp. 175-217.

Date Deposited: 25 Feb 2015 02:21
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity @ 34%
05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050209 Natural Resource Management @ 33%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 33%
SEO Codes: 96 ENVIRONMENT > 9607 Environmental Policy, Legislation and Standards > 960701 Coastal and Marine Management Policy @ 40%
96 ENVIRONMENT > 9609 Land and Water Management > 960903 Coastal and Estuarine Water Management @ 20%
96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960507 Ecosystem Assessment and Management of Marine Environments @ 40%
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