Climate change (in particular changes to carbon dioxide concentrations, temperature and precipitation) will affect the basic physical and chemical environment underpinning all life. Species will be affected individually by these changes, with flow-on effects for the structure and composition of current ecological communities. Ecosystem function and the services they provide will also be effected.

Climate change will result in shifts in suitable habitat for species, requiring species to move in order to adapt and survive. The ability of species to move in response to climate change within the Glenelg Hopkins region depends on their ability to disperse and the availability of suitable habitat. Improved connectivity through linking existing remnant vegetation provides many communities, species and their genes with the ability to move throughout the landscape. The movement of species is far more difficult to facilitate in coastal areas as species distributions are pushed southward and sea level rise and coastal erosion push northward limiting the available habitat and resulting in ‘coastal squeeze’.

Responses are likely to be species-specific due to complex interactions between changes in rainfall and temperature and the different thermal thresholds of species. Some species will be more vulnerable than others to extinction. Species may not be able to shift to areas with suitable climatic conditions due to being located in fragmented habitats, or because of their limited dispersal ability. Species with small, isolated or fragmented ranges, or those with low genetic variation and specific thermal requirements, will be more vulnerable and local extinctions are likely. Species currently listed as threatened are most vulnerable to extinction.

There are a range of factors that, in combination, form a cascade of responses and feedbacks within systems. The complexity of the effects of changes in climate on biotic interactions means it is difficult to predict responses. It is certain that overall declines in biodiversity will occur, and ecological monitoring will be essential in improving understanding of these processes. This will enable the development of strategies for effective biodiversity conservation and adaptive management[i].

Because the rate of climate change is likely to outpace the ability of most species to adapt, changes in the distribution of fauna and flora are expected to be a major response to climate change. Fauna which are sensitive to climatic conditions, particularly temperature, are generally expected to move poleward, towards higher latitudes and up-slope to higher altitudes in response to increasing temperatures. An average global shift poleward of 6.1 km per decade has been estimated[ii].

Increasing urbanisation, agriculture and land use change will potentially act as barriers to movement of species. If species are unable to cross the region’s urbanised and modified habitats in response to the changing climate they are likely to become extinct. The loss of marginal habitats including the coastal fringe is likely and interactions between a changing climate and habitat loss and change will result in species extinctions and an increasingly homogenised flora and fauna[iii].

To facilitate the best possible chance for species and community adaption, remaining habitats must be protected and managed, degraded habitats restored and connectivity between habitats increased. It is preferable to allow for natural distribution shifts and adaptation; however, genetic translocation may become an option. The movement of individuals and therefore genes could increase the genetic diversity and therefore the resilience of species[iv]. Assisted colonisation may also be possible for a small number of vulnerable species[v].  This is not only an issue for species currently within the Glenelg Hopkins region but also for species whose climatic envelope is not currently in the region, but will shift to be within the region in the future[vi].

Changes in life cycle events (phenology), such as flowering, emergence, breeding and migration, have been identified as one of the most important impacts of climate change on biodiversity. Such events are important determinants of species distributions, species interactions and the structure and function of all ecosystems. The response of species to climate in Australia has been predicted to occur on average four days earlier per decade[vii]. There is a lack of long-term monitoring of the timing and nature of species life cycle events.  It is not yet possible to predict how the life cycles of specific species might change within the Glenelg Hopkins region.

Climate change impacts are likely to be exacerbated by acting in combination with other threats to biodiversity, such as habitat loss, degradation and land use change, introduced species and diseases, and altered water resources. If native species and communities are to have the best chance of adapting, all threats must be addressed simultaneously.

 

[i] NCCARF Terrestrial Biodiversity Network, Terrestrial report card 2013: Climate change impacts and adaptation on Australian biodiversity, National Climate Change Adaptation Research Facility, Gold Coast, 2013.

[ii] C Parmesan, and G Yohe, A globally coherent fingerprint of climate change impacts across natural systems, Nature 421, 37–42, 2003.

[iii] C Parmesan, Ecological and evolutionary responses to recent climate change: annual review of ecology, evolution and systematics 37, 637–669, 2006.

[iv] ID Lunt, M Byrne, JJ Hellmann, NJ  Mitchell, ST Garnett, MW Hayward, Using assisted colonisation to conserve biodiversity and restore ecosystem function under climate change, Biological Conservation 157, 172–177, 2013.

[v] SM Prober, KR Thiele, PW Rundel, CJ Yates, SL Berry, M Byrne, L Christidis, CR Gosper, PF Grierson, KL Lemson, T Lyons, C Macfarlane, MH O'Connor, JK Scott, RJ Standish, WD Stock, EJB van Etten, GW Wardell-Johnson, A Watson, Facilitating adaptation of biodiversity to climatic change: a conceptual framework applied to the world’s largest Mediterranean-climate woodland, Climatic Change 110 (1-2), 227–248, 2012.

[vi] S Garnett, D Franklin, Climate change adaptation plan for Australian birds, CSIRO, Collingwood, 2014

[vii] LE Chambers, R Altwegg, C Barbraud, P Barnard, LJ Beaumont, RJM Crawford, JM Durant, L Hughes, MR Keatley, M Low, PC Morellato, ES Poloczanska, V Ruoppolo, RET Vanstreels, EJ Woehler, AC Wolfaardt, Phenological changes in the southern hemisphere, PLoS ONE, 2013.