Managing living collections and landscapes in a (climate) changing world

Botanic gardens maintain collections of living plants for science, conservation, education, beauty and more. These collections change over time – in scope and content – but the predicted impacts of climate change will require a more strategic approach to the succession of plant species and their landscapes.

Royal Botanic Gardens Victoria has recently published a ‘Landscape Succession Strategy’ for its Melbourne Gardens, a spectacular botanical landscape established in 1846. The strategy recognizes that with 1.6 million visitors each year, responsibility for a heritage-listed landscape and the need to care for a collection of over 8,000 plant species of conservation and scientific importance, planting and planning must take into account anticipated changes to rainfall and temperature. The trees we plant today must be suitable for the climate of the twenty-second century. Specifically, the Strategy sets out the steps needed over the next twenty years to transition the botanic garden to one resilient to the climate modelled for 2090.

The document includes a range of practical measures and achievable (and at times somewhat aspirational) targets. Climate analogues are being used to identify places in Australia and elsewhere with conditions today similar to those predicted for Melbourne in 2090, to help select new species for the collection.

Modelling of the natural and cultivated distribution of species will be used to help select suitable growth forms to replace existing species of high value or interest. Improved understanding of temperature gradients within the botanic garden, water holding capacity of soils and plant water use behaviour is already resulting in better targeted planting and irrigation.

The goal is to retain a similar diversity of species but transition the collection so that by 2036 at least 75% of the species are suitable for the climate in 2090. At all times there will be a strong focus on assisting the broader community in their response to climate change. An international Climate Change Alliance is being established to further encourage the sharing of knowledge and skills.

It is unlikely they will find a reasonable solution in this critical period. Perhaps all these need to become carbon neutral while they keep using fossil fuels, thus giving them the chance to contribute during the carbon emergency of the next 12-15 years, and planting millions of trees for their multiple benefits.

Professor Tim Entwisle

Tim is a highly respected scientist, scientific communicator and botanic gardens director. He took up the role of Director and Chief Executive of Royal Botanic Gardens in March 2013, following two years in a senior role at Royal Botanic Gardens Kew, and eight years as Executive Director of the Royal Botanic Gardens and Domain Trust in Sydney.

Tim is an Honorary Professorial Fellow in the School of Botany at The University of Melbourne and has been a Visiting Professor in the School of Biological and Biomedical Science, Durham University. He is an expert in freshwater algae (a genus, family and order of algae were named after him last year) but has a broad interest in all plants and related life forms (e.g. he edited and wrote for the 4-volume Flora of Victoria).

Tim blogs, tweets, and looks for any opportunity to promote science, plants and gardens. Tim has been a regular contributor to ABC radio and its website, and a frequent guest on Australian radio – over summer 2014/15 he hosted RN’s first plant and gardening show, Talking Plants, which ran for a second season in 2015/16. He has written for a variety of science, nature and garden magazines and maintains an active social media profile (including his popular ‘Talkingplants’ blog). He is currently President of the International Association of Botanic Gardens (IABG).