Zoo Tales Blog: Gardening for Gorillas – Trials, tricks, and triumphs of a zoo horticulturalist

For Zoo Tales week, Stephen Butler, Curator of Horticulture at Dublin Zoo, introduces Gardening for Gorillas and the symbiotic significance of plants in the animal world...

I love plants. Pure and simple. A zoo is for animals, isn’t it? Yes, but animals need plants need animals, so many links. Plants are the physical structure of many natural habitats, and of course are at the bottom of almost all food chains. So, in a zoo, plants can be very useful in many ways.

Plants contribute, naturally, to the five freedoms of animal welfare. Carefully chosen, plants provide enrichment, natural feeding, or play. Plants provide shade and shelter. Plants allow normal behaviour, food gathering and climbing. Plants provide screening from other animals (and, dare I say, visitors).

Plants add immensely to the ambience of the zoo, creating, with careful plant choice, a unique character to different areas. Being surrounded by plants is beneficial to our feelings and health, and surely the animals feel better too. Plus, all the benefits of carbon storage and rain absorption in planted areas. Plants can also be an incredible educational resource.

I spent 37 years increasing the planted aspect of Dublin Zoo. The Victorian fence lines slowly disappeared, and some animal areas were planted too. Each animal has their own challenges though! Geese ruled the lake edges, finding plants to resist their beaks – and feet – was indeed a long, drawn-out contest but the plants ultimately won. At the opposite end of the scale, I found plants that elephants would not touch!

On retiring I considered writing about my experiences. There is, to my knowledge, no other book that details planting with zoo animals and the unique challenges presented. The combination of possible soil damage from feet, damage from teeth, lips, or trunks, and the physical breaking or pulling up of plants can at times be hard to beat.

But, and it’s a very useful, and big, but, zoo horticulturalists are beating the animals – in the nicest possible way of course! Designing a new exhibit for animals must include the horticultural team from day one – design planted areas that allow the plants to grow, enough soil depth and root area especially, adequate light, and irrigation if needed – protected in such a way that the animals cannot access and damage, or maybe not access too much. Information about the animal behaviour, and dietary preferences, is key to the horticultural team succeeding on the plant side. If plants are not palatable they may be left alone, the trick is not to have anything actually toxic….

Even better, the zoo horticulturalists have become organised, with regular conferences, newsletters, and articles. More importantly, they have developed a website www.zooplants.net. This lists hundreds of plants used in hundreds of exhibits. So, for any new exhibit/habitat being planned, the horticulturalists can refer to the website and see examples of plant use in other zoos – what worked, or maybe didn’t – an incredible resource.

There are two examples from the book Gardening for Gorillas that I refer to often. Purple willow Salix purpurea with the gorillas. The animal team reckoned all planting would be pulled up in days. The gorillas sampled the willow the first day – and spat it out in disgust! Full of salicylic acid, harmless but incredibly bitter. Completely ignored, the willows flowered in spring after 4 years….and the gorillas then ate them – but only the probably acid-free catkins, so much so that they had green chins from the pollen. Perfect temporary enrichment. The orangutan new island was very heavily planted with shrubs trialled and left alone by the gorillas. The mix included cardoons, Cynara cardunculus, with very large felty leaves. Left alone at first, the orangutan then started stripping the leaves off. Laid in a neat pile they were insulation from cold or wet ground. Again, great enrichment and no real harm to the plant.

The book has chapters on different habitats, and information about the horticultural input in the design process, problems encountered and solutions found. A chapter on soil compaction caused by animals, using urban soil and perhaps grass reinforcement mesh, is extremely useful – muddy conditions are not good for staff or animals! A much larger chapter details the educational aspects of some of the plants used around Dublin Zoo. The Education Team were keen to use the resource that grew all around them, but didn’t know enough about the plants. A spreadsheet was developed by the horticulture team listing the plants that could be used, in different seasons, as examples – pollination or medicinal use say – information that is being uploaded to www.zooplants.net too.

If my book helps encourage more zoos to use more plants, for the animals’ benefit, and for the visitors as a pleasant background, with educational tours that include plants too, I’ll feel the effort was well worth it.

www.gardeningforgorillas.com

Stephen Butler Dip Hort Kew, Editor for ZooLex

Curator of Horticulture, Dublin Zoo, 1981-2018

All blogs reflect the views of their author and are not a reflection of BIAZA's positions.