Managing Marvelous Mangroves
Population growth, resource use and decline, habitat and biodiversity loss, food security, climate change and the spread of diseases are issues facing society at present and into the future (Harris, 2009). These issues are interconnected and respond to one another. In order to mitigate the impact of these issues, or eradicate them, we need to get smart and understand the complex adaptive system we utilise and the ecological principles that improve sustainable outcomes.
Why are mangroves complex?
Mangroves are examples of complex adaptive system. For a system to be considered ‘complex adaptive’ they must be spread out across various locations. Mangroves are found throughout the subtropics and tropical regions of the world between 30N and 37S, such as in the Asia-Pacific. However, they are also found in temperate South East Australia and New Zealand’s North Island (Harty, et al. 2009; Feller, et al. 2010). Generally, they are not found in more polar climates. Climatic factors influence the distribution of these ecosystems such as temperature and moisture, in addition with coastal processes such as tidal mixing and coastal currents, influencing propagule dispersal (McLeod & Salm, 2006). Furthermore, mangroves are non-homogenous, meaning they are made up of many different vegetation zones that provide a border between land and sea (Feller, et al. 2010). Furthermore, they have non-linear thresholds, which characterize the relationship between fishes and mangroves (Shielder, et al. 2017).
What do we have to do with it?
Mangrove ecosystems provide direct and indirect benefits to human activity, as well as sustaining biodiversity (Feller, et al. 2010). They have recreational, cultural, economic and industrial values to society. Thus, these ecosystems are often shared with humans and impacted by human activity. Adding an additional layer of complexity. In shared natural and human systems, such as mangroves, feedback loops are formed (Liu, et al. 2007). For instance, in response to the removal of mangroves, sediment features and the composition of animals that live in the seabed such as crabs, is changed. These changes will differ among habitats across various scales (Alfaro, 2010). Additionally, if sea-level rise increases and mangrove ecosystems are no-longer ‘vertically’ built then the ecosystem will become a sub-tidal system (Feller, et al. 2010)
Resilience is an ecological principle that can assist with achieving sustainability outcomes. Resilience is the capacity to be able to recover from an event/disturbance, i.e. storm, tsunami. (Holling, 2001). In human-nature ecosystems, humans contribute to maintaining resilience. As demonstrated in Wisconsin, where human-nature resilience is achieved by allowing Native American people to manage their lakes and lands sustainably (Liu, et al. 2007). Mangroves are generally resilience in the face of natural events, a study has shown that mangroves have demonstrated resilience over time, even in the face of shoreline fluctuation (Alongi, 2008).
How can we achieve sustainability?
To achieve sustainability there are various actions that need to take place. Firstly, humans need to reduce their ecological footprint. Secondly, a complex adaptive thinking hat needs to be worn. We must understand that within these socio-ecological systems, many other connections are occurring. Uncertainty and unpredictability are also a factor.
On a local scale, mangroves in New South Wales are transitioning into saltmarshes. This could be a feedback response to a variety of processes induced by natural events and human activity, such as:
• Sea level rise
• Increased rainfall, reducing soil salinity
• Increased nutrients
• Mangroves recolonizing cleared areas
• Modification of estuary entrance
In response to these feedbacks and maintaining resilience in mangrove ecosystems strategic planning policies. Protecting these ecosystems has been in embedded in the New South Wales Coastal Management Act, 2016 No. 20.
Kingsford (2011) conducted a synthesis of preservation management of wetlands and rivers under climate change. Kingsford (2011) suggests that mangroves can flourish by recovering flow regimes, altering dam operations and applying protected-area management and improving government and adaptive management. This ultimately will assist in improving the resilience of the ecosystem by managing connectivity and maintaining diversity.
Kingsford (2011) suggests management tools to enhance sustainability in mangrove ecosystems. It is suggested that stakeholder engagement is required to determine the anticipated condition of a particular ecosystem, then develop objectives for long term planning and management. He also discusses how strategic adaptive management is suitable for these complex ecosystems, which provides a framework for stakeholder engagement and involvement. Ultimately this approach links objective to targets, promotes transparency and accountability and management. Furthermore, strategic planning incorporates incompatible values and demands with technical information that influences land use planning and management actions. Additionally, Integrated Coastal Zone Management accounts for ecological, economic and social values (Harty, 2009).
By understanding complex adaptive systems, such as mangroves, we can incorporate ecological principles into community and stakeholder engagement activities to come to conclusions and ideas of how mangroves can be better management. Thus, this can be incorporated into policies and strategies that can take action to achieve sustainability outcomes.
Alongi, D. M. (2008). Mangrove forests: resilience, protection from tsunamis, and responses to global climate change. Estuarine, Coastal and Shelf Science, 76(1), 1-13. #
Harris, G. (2009). Seeking sustainability within complex regional NRM systems. In Natural Resource Management (Place and Purpose Symposium) (pp. 1001-1014). *
Harty, C. (2009). Mangrove planning and management in New Zealand and South East Australia–A reflection on approaches. Ocean & Coastal Management, 52(5), 278-286. *
Holling, C. S. (2001). Understanding the complexity of economic, ecological, and social systems. Ecosystems, 4(5), 390–405. https://doi.org/10.1007/s10021-001-0101-5 *
Kingsford, R. T. (2011). Conservation management of rivers and wetlands under climate change–a synthesis. Marine and Freshwater Research, 62(3), 217-222.
Liu, J., Dietz, T., Carpenter, S. R., Alberti, M., Folke, C., Moran, E., ... & Ostrom, E. (2007). Complexity of coupled human and natural systems. science, 317(5844), 1513-1516.*
Feller, I. C., Lovelock, C. E., Berger, U., McKee, K. L., Joye, S. B., & Ball, M. C. (2010). Biocomplexity in mangrove ecosystems. Annual review of marine science, 2, 395-417. #
McLeod, E., & Salm, R. V. (2006). Managing mangroves for resilience to climate change. World Conservation Union (IUCN). #
New South Wales Coastal Management Act, 2016. No 20. Retrieved from: https://legislation.nsw.gov.au/#/view/act/2016/20/full #
Shideler, G. S., Araújo, R. J., Walker, B. K., Blondeau, J., & Serafy, J. E. (2017). Non‐linear thresholds characterize the relationship between reef fishes and mangrove habitat. Ecosphere, 8(9), e01943. #