Five lessons from the field: designing habitat into your vineyard

It is always a great opportunity to get out in the field and experience first hand how new technologies, the environment and our ecosystems work together in the vineyard. This October Wine Victoria partnered up with Goulburn Broken Catchment Management Authority to co-ordinate an event in Central Victoria supported by the Climate Smart Ag Program ‘Nature Services for Ag” project.

This event was motivated by grapegrowers based over in Heathcote, who were keen to come over and see what was happening at Tahbilk winery. The event evolved into a morning filled with interesting insights about how to diversify your vineyard and bring more nature in to help you.

We would like to thank Cathy Olive from Euroa Arboretum, Glenn and Matt from Fowles Winery and Zenon Czenze from University of New England for their time on the day to share their knowledge and help the audience practically understand how it is possible, when you are invested in making it work, to find a enhance your vineyards health. Thank you also to the Tahbilk team for hosting the event.

Here are our five biggest takeaways from the day.

Insight 1. Mow the inter-row now: it helps with frost and won't hurt seeding

If frost is a risk, mow the inter-row down now (October). At this time of year it won't stop your native grasses setting seed, so there is no trade-off between frost protection and building a healthier sward.

The timing works because spring mowing knocks back annual grasses before they flower and seed, while native grasses set their seed later, in early summer. The advice is to mow or graze regularly through spring, then rest native grasses over early summer while they seed. Native grasses respond well to this kind of rotational mowing or grazing.

Insight 2. Not all birds are equal: read them as a sign of landscape health

The birds you see around the vineyard tell you a lot. Farmland birds such as galahs, magpies and cockatoos are drawn to open landscapes, and they hold steady even when there is very little native vegetation left. Small insect-eating birds, the ones that actually help with pest control, have very different needs.

Research by Radford and Bennett (2002), presented on the day, showed how sharply this plays out:

At about 7% native cover, typical of farmland, you mostly see parrots, magpies and other open-country birds.
At about 10% habitat cover, many woodland-dependent species reach or come close to their extinction threshold, and individual species start declining well before that.
With large trees, around 18% tree cover and native grasses, the bird community becomes far richer, including robins, thornbills, fairy-wrens, pardalotes and other insect eaters.

Insectivorous birds like the Crested Shrike-tit need remnant patches larger than 5 hectares and creeklines wider than 50 metres. They also need dense cover to hide from predators, and avoid exposed edges. So if your small insect eaters are missing, it is a signal that the habitat around you is too thin or too fragmented.

Insight 3. Soil phosphorus is the best predictor of what will grow

Before you plant or sow anything, test your phosphorus (this can be as simple as seeing how far down your weeds grow). It was the single biggest indicator of what will or won't establish. Most of Australia's roughly 225 native grass species, and the wildflowers that grow among them, evolved in low-nutrient soils and are drought tolerant.

What tends to grow

Very low (5–10 mg) The widest range of natives: lilies, orchids, Blue Devil, Peach Heath, Kangaroo Grass, Wallaby Grass, Spear Grass.

Low (10–20 mg) A narrower native mix: Weeping Grass, Kangaroo Grass, Wallaby Grass, Swamp Dock.

Medium (20–50 mg) Natives mixed with exotics such as Annual Ryegrass, Sorrel and Barley Grass.

High (>50 mg) Mostly exotics: Annual Ryegrass, Barley Grass, Wild Sage, Capeweed.

Insight 4. Most bats stay close to trees

Insect-eating microbats are some of the hardest-working pest controllers in a vineyard. A bat can eat half its body weight in insects in a single night. However, the majority of species don't travel very far from the edge of remnant bush (20-50 metres from the nearest tree).

That means a vine row 100 metres from the nearest tree is largely out of their reach. Bats need to feed through the warmer months and shelter in tree hollows, under loose bark or in buildings. Keeping old, hollow-bearing trees and adding trees within and around blocks brings more of the vineyard into their range.

Insight 5. It's OK to plant in clumps: the reveg corridor isn't the only option

You don't need a long, skinny revegetation strip to make a difference. Planting in clumps is fine, and often better.

Narrow bands of vegetation suffer from edge effects: more exposure to light and wind, and more weeds, fertiliser, spray drift and stock.

The small insect-eating birds we most want avoid those exposed edges. Instead, connectivity can come from several shapes:

Clumps and stepping stones that let birds, bats and insects hop across the landscape
A mosaic of scattered paddock trees, which suits some species
Wide plantings where you do link two patches, because the wider the planting, the smaller the edge effect

If you're planting a shelterbelt, a few design rules help. It protects an area up to 20 times the height of the tallest tree. Aim for at least 3 rows, since gaps funnel jets of wind through, and 5 to 7 rows or more for the best wildlife habitat.

Think at landscape scale. Most species need a network of habitat to move through, and use different parts of the landscape daily, seasonally or irregularly. Small, isolated patches are easily wiped out by fire, disease, weeds or feral animals.