Location of the 100 Antony Gormley statues (numbered) at Crosby Beach, Liverpool.

<p>Locations of the statues are shown in relation to Great Britain. Also showing the direction of sampling positions used to assess barnacle abundance on the statues (north, south, sea, or shore) (Ordnance Survey © Crown copyright 2011).</p

Mean total abundance of barnacles (25 cm⁻²) per sampling position

<p><b>on each of the 100 statues.</b> In total 14 sampling positions were chosen to represent a range of environmental conditions experienced by the statues and were located at the same points on each of the 100 statues sampled at Crosby Beach, Liverpool (for statue locations see Fig. 2). Boxplots show the medians (thicker black line) and upper and lower quartiles of abundance values at each sampling point, with whiskers extending to the extremes of data points not considered to be outliers.</p

Predicted changes in log barnacle abundance (25 cm⁻²) in relation to shore height and direction.

<p>Sampling positions faced four different directions: north, south, sea, shore. Values are based on those predicted from a generalized linear mixed model output using the median value of Location (first principal component of latitude and longitude), the mean level of Rugosity of the sampling positions and exposed or sheltered levels of Exposure.</p

Generalized linear mixed models (GLMMs) of barnacle abundance (numbers 25 cm⁻²) in relation to important environmental variables at Crosby Beach, Liverpool.

<p>Model selection was based on Akaike’s Information Criterion (AIC) with additional interactions being kept if they reduced AIC by >2. The most parsimonious adequate model on this basis is shown in bold. <i>n</i> = 1400 quadrats; d.f., degrees of freedom; <i>l</i>, log-likelihood; Δ AIC, the difference in AIC from that of the most parsimonious adequate model.</p

Examples of the life-size cast-iron statues at Crosby Beach, Liverpool.

<p>Images show two of the 100 statues that form the art installation ‘Another Place’; one at the higher end of shore height sampled (left) and one at a lower shore height (right). The statues stretch over approximately 3 km of the foreshore and are distributed at a range of tidal heights.</p

Goodness of final model fit

<p><b>used to assess barnacle abundance on the statues at Crosby.</b> Goodness of fit of the final generalized linear mixed model is illustrated through assessment of the fitted values of the selected final model against the residuals of the model (red line indicates loess smoother).</p

Predicted mean abundances of barnacles (25 cm⁻²) per statue position

<p><b>in relation to their location.</b> Predicted mean abundances are based on predicted values from a generalized linear mixed model output, with contours indicating actual shore height of the statues.</p

Modelling Carbon Emissions in <i>Calluna vulgaris</i>–Dominated Ecosystems when Prescribed Burning and Wildfires Interact

<div><p>A present challenge in fire ecology is to optimize management techniques so that ecological services are maximized and C emissions minimized. Here, we modeled the effects of different prescribed-burning rotation intervals and wildfires on carbon emissions (present and future) in British moorlands. Biomass-accumulation curves from four <i>Calluna</i>-dominated ecosystems along a north-south gradient in Great Britain were calculated and used within a matrix-model based on Markov Chains to calculate above-ground biomass-loads and annual C emissions under different prescribed-burning rotation intervals. Additionally, we assessed the interaction of these parameters with a decreasing wildfire return intervals. We observed that litter accumulation patterns varied between sites. Northern sites (colder and wetter) accumulated lower amounts of litter with time than southern sites (hotter and drier). The accumulation patterns of the living vegetation dominated by <i>Calluna</i> were determined by site-specific conditions. The optimal prescribed-burning rotation interval for minimizing annual carbon emissions also differed between sites: the optimal rotation interval for northern sites was between 30 and 50 years, whereas for southern sites a hump-backed relationship was found with the optimal interval either between 8 to 10 years or between 30 to 50 years. Increasing wildfire frequency interacted with prescribed-burning rotation intervals by both increasing C emissions and modifying the optimum prescribed-burning interval for minimum C emission. This highlights the importance of studying site-specific biomass accumulation patterns with respect to environmental conditions for identifying suitable fire-rotation intervals to minimize C emissions.</p></div

Locations of the four heath/moorland study sites in Great Britain.

<p>Geographic coordinates for Kerloch: 56°58’N, 2°30’W; Moor House: 54°41’N, 2°24’W; Howden: 53°28’N, 1°42’W; and Dorset: 50°43’N, 2°07’W.</p

Parameter estimates for the final generalized linear mixed model (GLMM) assessing the influence of various factors on the abundance of barnacles.

<p>Parameter estimates for the final generalized linear mixed model (GLMM) assessing the influence of various factors on the abundance of barnacles.</p