Study site

Management

Field of Mars Reserve is a bushland reserve managed by the City of Ryde local government area. It exists for the purposes of ecosystem conservation, public nature appreciation and as a site for scientific research.

Vegetation communities

There are three broad vegetation community groups in the reserve. These are wetlands, closed forests and open forest/woodlands. Scientists have further classified the vegetation communities into specific sites and mapped them in the Vegetation communities at Field of Mars Reserve (PDF).

The pattern of vegetation is largely influenced by soil types and where they occur in the landscape. Other influences include climate, drainage patterns, aspect, fire frequency and human activities.

Threats

Like so much of Sydney’s bushland, Field of Mars Reserve is threatened by introduced species such as weeds and feral animals, as well as problems to do with stormwater runoff such as elevated nutrient loads and erosion.

These pressures are compounded by the influence of the changing climate - warmer average conditions and more extreme weather events, as explained in the Weeds and climate change fact sheet by the Invasive Species Council (PDF).

Reducing the impacts of weeds and preventing new weeds are essential to increasing the resilience of ecosystems. This gives native species the best chance to deal with the adverse impacts of climate change and other pressures.

Soil types

Hawkesbury Sandstone weathers to form thin, sandy soils with low nutrient and water retaining qualities. This soil type is common along the ridge lines and mid-slopes of the valley.

These nutrient-poor soils are highly erodible and hence are extremely susceptible to disturbance. For example, sheet erosion increases substantially wherever the vegetation is disturbed, and can be particularly severe following bushfires, whilst minor to severe gullying frequently occurs on unpaved roads and tracks.

Soils on the highest ridges are typically a medium-heavy clay texture, while on the ridges and slopes sandy topsoils cover sandy clay subsoils. Near the valley floor loamy sand soils mix with alluvial deposits.

The thickness of the top 'O layer' of the soil (humus or organic matter such as decomposing leaves) varies.  It tends to be much thicker closer to the valley floor, particularly under areas that are dominated by introduced plants.

The pattern of vegetation is largely influenced by the soil types and where they occur in the landscape. Other influences include climate, drainage patterns, aspect, fire frequency and, of course, human activities.