Managing a small block of remnant native vegetation drives home some basic principles in natural resource management, and highlights the sort of trade-offs that must be made.
Lessons from a semi-urban, residential block also apply to other scales and environments.
The family home is on a small bush block on the outskirts of a city. We love the bush and bush-regeneration is a major objective for our block. So is bushfire prevention and safety. Often the two go hand in hand. Growing beneath a eucalypt over-story, feral olives and watsonia are our main weeds – they obliterate most things trying to grow below them. Clearing them reduces fire risk and gives natives an opportunity to flourish. Sounds like one of those fabled ‘win-win’ results.
Success comes as native seedlings emerge, but having to spot and skirt seedlings makes it harder to slash prior to summer, and some plants want to grow in passive fire-break areas where we don’t want anything apart from very low vegetation. The trade-offs are more time and effort in slashing or hand-weeding and, close to the house, fire-protection outweighs biodiversity.
Change can be slow.
Areas once covered by weeds are now supporting wattle seedlings, the occasional eucalypt, and native fan-flowers, while existing native grasses thrive. It has taken four or five years for seedlings to emerge. We hope other species will eventually appear as the new plants grow and alter their environment. A range of lag-times have to be factored into environmental management. Riparian managers, especially, understand this.
It can get worse first.
Not all change following the removal of major weeds is positive. There is now a wider range of weed species present, which are mostly annual. We hope that, with weeding, judicial spraying, and slashing before flowering, they will eventually be overtaken by more preferred species – but it can sometimes be ‘one step forward, two steps back’.
Removing weeds like feral olives also removes habitat that some native animals rely upon. We’ve learnt that blue wrens seem to love olives. As soon as we removed a thicket of young olives near the house, the wrens stopped calling and retreated to neighbouring blocks further down the valley. When I was about to fell a tall olive tree, a ring-tail possum appeared from its camouflaged drey to watch. It was close to the property boundary, so that weedy tree was allowed to remain. We hope that native regrowth will eventually provide better opportunities for the animals losing out through our weed removal program.
Some changes are reversible.
From their age and height, it is apparent that feral olives had previously been removed from part of the block, but been allowed to regrow. It is a good reminder that some changes in the environment are reversible, and some are not. Working in modified systems takes ongoing effort to support the changes we’ve elected to pursue. The fundamentals like weed control are not once-off events. We are lucky in not having any rabbits here to kill off the native seedlings.
Patches can’t be divorced from landscapes.
Our small block is on the side of a valley, and most neighbouring blocks are similarly mainly remnant eucalypt, with olives dominating the mid-story and a mixed understory of native and weed species. The odd block is mostly cleared, and slashed or grazed to contain fire risk. Foxes live in the valley.
The mosaic of management approaches means we are vigilant about the re-introduction of weeds we’re controlling, but thankful those differences mean fauna dis-advantaged by our efforts have a chance to retreat nearby. Fox control is beyond our individual means, and thankfully rabbit control is not needed, as pest control is a big challenge for individuals on small blocks in a semi-urban area. Some things can be managed at a ‘property’ scale, but others need neighbourhood (or ‘landscape’) approaches – necessitating a much greater degree of community engagement and social challenge.
One step at a time.
We didn’t have a grand plan when starting to clear the block of dominant weeds – just a need to reduce fire risk near the house and a desire to get some native re-growth. That worked, and over successive years we have progressively pushed the ‘weed-line’ further down the valley. Natural resource management is often like that – the most important step is the first one. You don’t have to hold-off trying to amass resources to beat a big problem in one go. Be content to whittle away at big challenges while operating within your capability, and accept the inherent compromises in return for some progress. Make a start – you never know where you’ll end up once you get going.
We won’t own the land for ever, and there is no guarantee future owners will have the same management goals as us. Weed re-infestation could easily occur. That’s a risk we’re happy to take. The satisfaction of seeing the block slowly becoming ‘more native’, while also reducing fire risk, makes the effort worthwhile. Our actions aren’t always motivated by rational, economic thinking alone.
In summary, the management lessons illustrated on the block are:
- Natural resource managers often have to make trade-offs.
- Change in resource condition may be slow – and things might get worse before they get better.
- Some changes are reversible, some are not. Ongoing commitment can be needed to maintain ‘improvements’.
- Patches can’t be divorced from landscapes – there are implications for both from the management of each.
- The best thing a manager can do, is to make a start – have a go and learn from that.