So, yesterday’s argument was that the place to focus our conservation attention is the matrix, the area outside the preserves. Where we live. if you start viewing our suburbs as the new habitat, how does this start making our cities and our gardening and farming habits look?
To some degree we’ve started to take action already, without really conceptualising what it is that we’re doing. It’s all scattered though, and usually driven by one group or one species-of-interest, in a kind of haphazard “if enough people hear our message something might improve” kind of way. Generally there’s no big strategy. Which means you get some results, equally haphazard though all valuable none-the-less. I’ll break down some of the programmes I know of into the three effects mentioned yesterday – movement and dispersal, resource availability and the abiotic environment.
Existing movement and dispersal programmes are basically about putting corridors through the matrix. The most successful I know of is the Regent Honeyeater project in Victoria, which strategises how and where it plants new habitat (resources) in order to connect bushland fragments and so double its results, but there are many others done by landcare groups, by Men of the Trees, by individual farmers. They’re mainly agricultural though. In cities, I hear rumours of a plan within the City of Melbourne (not the greater area) for green corridors. I don’t know how much it’s being implemented, but the prevalence of “linear parks” in greater Melbourne makes developing corridors comparatively easy if there’s a will to. The Botanic Gardens and Parks Authority in Perth has a vested interest in urban green corridors as it manages Kings Park and Bold Park, which are large remnant urban bushlands with high education and conservation value. The two parks are separated by a lot of low-density-built-up areas, parks, ovals, undeveloped blocks and similar allowing them to have an informal corridor, and BGPA staff work at liaison with neighbouring land managers to try and protect that corridor where they can, but nothing is formalised. The Perth Greens have a “Greenways” plan they’d like to see adopted that would create green corridors all around the city and put every Perth resident within reach of the greater urban forest, so they’re thinking a bit this way too.
The abiotic environment efforts are a bit more varied – and usually a result of local council management practices that balance safety, finance and aesthetics with conservation. Some work has been done in some councils to get a strong environmental voice into this process (and where needed to adjust the concept of “aesthetics” to something less English estate), and some council planners are more switched on than others – local results will vary. The simplest tactic / practice change I’ve encountered is just to lay mulch between wetland reeds and parkland lawn, to avoid the question of “is this boundary area reeds with weedy grass or grass with weedy reeds?” – a question previously won by the council lawnmowers, with the effect of slowly shrinking wetlands. There are other tactics for creating clear boundaries between preserve and surroundings too, with varying results in terms of light, heat, fire spread, invasion potential and inadvertent “fence” effects. Then there’s disturbance. Any land managers of urban patches will already have fire prevention and safety schemes in place, involving track management and clearing, and hopefully many of those have been implemented with thought to their effect on the patch in mind. No guarantees – I recall taking a local councillor on a walk through a tiny urban fragment the size of a house block many years back, because their land management staff had recommended putting a wide concrete path with cleared edges through the middle of the block for fire and access issues. We were able to show her that on a block that tiny the best quality wildflowers were only found in the middle, and a wide cleared path through it would remove almost all of what people came to see – while fire prevention was important given that there were houses immediately on two sides, simply widening the existing firebreak at the edge of the patch would be sufficient and of much less impact.
Resource availability is where the existing programmes really come in. It’s easy for people to think about what they can put in their yard, and the species most able to make use of random resource availability at large spatial scales tend to be charismatically visible. Think Frogwatch, which encourages people to build frog habitat in their yards and make gardens frog-friendly. Or any of the butterfly-garden initiatives brought to you by local museums and zoos around the country, which mostly encourage the planting of tubular nectar flowers for butterflies to feed from (an easy sell to gardeners) but which do sometimes discuss what plants make caterpillar food. A talk given at Perth’s Herb Society many years ago mentioned nettles – there is one particular butterfly, the Yellow Admiral, whose caterpillar only feeds on Urticarias. These butterflies will travel significant distances to lay their eggs in a good food supply. We’ve removed most of its native supply, but planting nettles can replace it. There’s another butterfly whose native food supply we’ve also largely removed – but at the same time we introduced the South African weed called Cape Daisy which has taken off all over Perth, and it was able to use that as a new food supply so that butterfly’s doing fine. I forget its name, it’s one of the many orange-brown-black ones, but I saw one spending a lot of time in my front garden last winter/spring when my carefully-left-to-grow swathe of Cape Daisies was flowering. No coincidence that their leaves looked a lot more ragged after that. Another resources effort is a recent initiative to plant food for our two endangered species of white-tailed cockatoos. They eat, in the wild, 100 of the large Marri nuts a day, or when those aren’t available, 1000 of the much smaller Jarrah nuts. Marri and Jarrah are large eucalypts that we’ve mostly removed from the urban area because they’re too big for dense housing ratios. The cockatoos have somewhat replaced their food options by invading our pine plantations. But the pine plantations are being developed, so that food supply is drying up too. The Friends of Kings Park at their native plant sales mark the plants that are known food plants for the cockatoos, so that you can choose to increase the food available to them. Last spring, I bought and planted a Red Pokers Hakea from them partly for that very reason.
So, if that’s the sort of thing that exists, what’s next? This three-effect and five-adjustment method of looking at the matrix leads to some possibilities jumping out to me – you might see others suited to your area. In particular, I notice that the idea of temporal variation and scale doesn’t really enter into the efforts so far. The ideas of making temporary, seasonal corridors or of coordinating our plantings of types of food trees so as to ensure year-round supply aren’t visible. I also note that the idea of spatial variation – what landuse is in the matrix – could be used and coordinated more consciously, to provide different types of corridor or foraging for different ranges of species. Discussing this with the urban planners who lay out new estates would be good. Our community groups and eco groups are doing a lot of work on providing resources, which is great though it could be more strategic. And there’s room for the councils to look carefully at their abiotic environment management practices.
With movement and dispersal there’s no reason we can’t treat our suburban verges and streetscapes as corridors. It would take some community coordination and council cooperation but it’s possible. Our freeways act as large corridors given their size and usual native landscaping, but they need crossings for wildlife built into the exit and entry ramps. They also need their plantings considered from a resources point of view, more thoroughly than just the question of “what plants will not attract wildlife that will become a traffic hazard”.
In terms of resources, we could create zones around patches and along rivers or corridors in which people are encouraged to provide the food and habitat resources needed by species in the patch, as well as to reduce domestic-animal predators (such as the cat-free zones in Melbourne’s northeast). That could double the effective extent of the patch for many species, though not all – for instance, the blue wrens need thick cover for safety and won’t cross most roads (let alone paddocks and ovals) as they’re uncovered and too wide. So putting occasional tree plantings on roads and median strips that would allow for canopies from each side to touch and provide shelter would allow more species to cross over. Another possible strategy for resource availability is to teach and encourage the unpopular concept of reducing productivity. In this case, to encourage people to plant such things as almond trees, or crops of sunflowers and peanuts, in the certain knowledge that they will mostly lose the harvest to the birds. To net one tree and leave another unnetted. To only pick a third of a crop for oneself and allow the insects and snails to eat their fill that they in turn can be eaten by planarians or frogs or lizards. That’s a bit cutting edge, though it’s a concept I’ll come back to another time.
How much we can see the urban landscape as an extension of the native patches we’re protecting, I don’t know. Environmental rehabilitators have for a long time looked at how the matrix affects patches, with invasions of garden weeds, aquatic weeds from fishtanks and rubbish or trampling from visitors and so on. To see patches reaching out into the matrix instead is a bit of a change of thinking – but an important one, that might make quite a difference for some of our native flora and fauna. Especially those that are less mobile and perhaps less obvious compared to screeching cockatoos and colourful butterflies. Whether it’s creating new corridors with our street trees and front gardens and verges to link patches, or marking areas alongside reserves and rivers and encouraging homeowners in those areas to plant the food resources for species known to live in the reserves so that their effective foraging area is doubled, there’s a lot of room for us to create cities that are still habitat.