In our garden, we are blessed with a medium sized karaka tree.
This is a New Zealand endemic species that is relatively abundant around the Hibiscus Coast – found in coastal forests, and some of our parks and reserves. They can also do well in our gardens.
Karaka is the te reo Māori word for orange, and this tree is so named because of the gorgeous and large orange fruit that they produce during the summer.
Besides simply being a beautiful tree, karaka also provide a critical food source for our endemic kererū (New Zealand pigeon).
If you ever get a chance to watch a kererū in a fruiting karaka tree, make sure to take the time to do so. The pigeon will carefully select a tasty looking fruit, pluck it, and then appear to start gagging on it as it works the large berry into its mouth. It looks like quite a struggle and just when you think the kererū is going to choke itself to death – the fruit is gone. Then the bird will carefully select the next juicy looking fruit to consume.
But karaka do not give away the fruit for free – they provide it in exchange for a critical service that karaka trees depend on: seed dispersal.
Surrounding their seeds with nutritious (and maybe delicious) food, karaka ensure that kererū will happily swallow the seeds and eventually fly off.
After digesting the fleshy part of the fruit, kererū excrete the intact seed far away from the parent tree.
Kererū is the only bird in New Zealand big enough to swallow the large berries of the karaka tree – other native species that could handle karaka fruit, such as moa, are extinct.
Seed dispersal is just one of many ecological services that healthy ecosystems critically depend on. Others include flower pollination (including our crops), purification of air and water, soil generation and carbon storage.
Ecosystems are vast networks with countless links, like the karaka-kererū one, that have co-evolved between species.
By planting native species like karaka, pūriri, kowhai, kohekohe, and coprosma in our gardens we can increase the links in the local ecological network and have healthier ecosystems that extend and surround us. And more kereru too!