Key Learning Points

1. 1. Although intra-abdominal hypertension and abdominal compartment syndrome (ACS) form part of a scale in clinical practice, they are different entities as the former may be chronic, but the latter involves acute organ failure.

2. 2. The prevalence of ACS in the intensive care unit has been reported as 8.2 per cent, with a higher prevalence in medical patients (10.5 per cent), compared to the surgical cohort (5 per cent).

3. 3. Palpation of the abdomen is highly unreliable as a method of detection.

4. 4. A standardised measurement protocol is important to avoid significant inter-individual variability.

5. 5. Management of these syndromes should be protocol-based and multi-modal.

The search for the mechanisms that drive the species–area relationship (SAR) has been complicated by a number of factors. First, the different proposed mechanisms have generally been considered to be mutually exclusive. Second, due to the misinterpretation of curve shapes after (log) transformation of one or both of the axes. Third, due to confusion about different types of SAR, such as isolate and sample area SARs. These two SAR types are underpinned, at least partly, by different factors (or drivers), which act in combination. The different patterns and processes that drive the SAR can be organized according to a hierarchy: from underlying environmental patterns at the bottom, through the processes driving species diversity patterns, up to the research and sampling design. Environmental patterns include both biological and geographical patterns, while processes may be stochastic, evolutionary or ecological. The resultant species diversity patterns include species range patterns, species densities, species abundances and the spatial distribution of individuals of a species. Although the individuals of a species are rarely randomly distributed in space, the random placement model provides a useful null model that can be used to partition the effects of species abundances and the spatial distributions of individuals on SARs.