Basic hypotheses:

see Alba et al 2017 for details

Active rainfall manipulation involving five treatments in sheltered plots (each with 6 replicates):

Ambient

+50%

-50%

Altered frequency (one rain event every 3 weeks, representing ambient rainfall during that period)

Summer drought (typically Dec-end Feb, each Australian summer)

The objectives of this long-term study are: (1) to assess the effects of directional and prolonged changes in precipitation amount and variability on population, community and ecosystem processes; (2) to elucidate the mechanisms behind those changes, and finally (3) to predict the future state of drylands functioning under novel climate conditions.

The site is a lowland heathland on sandy moraine co-dominated by the shrub Calluna vulgaris and the grass Deschampsia flexuosa.

It is 57 m a.s.l. and 3 km from the sea. Precipitation at the site is 550 mm (30 yr mean), annual temperature is 7.7 °C (30 yr. mean) (average January 1.7 °C, average July 17.5 °C). 

Nitrogen deposition is in the low end of the range within the INCREASE network with c. 13 kg N/ha/yr (3 yr mean in wet deposition).

We use the Gherardi et al approach, passive drought shelter, collect water and pump on to irrigated plots.

We record community composition with individual-level mapping, which gives us demographic data, but means our community level data are a little "nonstandard" (some life forms represented as canopy cover, others basal cover, others just density).