Modelling Hen Harrier Dynamics to Inform Human-Wildlife Conflict Resolution : A Spatially-Realistic, Individual-Based Approach

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Flow diagram of model year cycle.

<p>A figure illustrating the main demographic and model processes in the annual cycle of the model.</p

Simulated national hen harrier breeding population growth between 1989 and 2030.

<p>The mean (± standard error) of the annual number of breeding pairs of hen harriers averaged across twenty replicate simulations. “Breeding pair” refers to a male and a female in a single territory which attempt to breed, whether successful or not. Black: non-breeding males and females of age 1 were added in the initialisation (SE range: 0.8–47.8). Grey: no non-breeding males or females introduced at the start (SE range: 2.1–27.5). Dashed lines indicate SE boundaries. Red circles denote the estimates and the red error bars indicate the range of the 95% confidence intervals from the censuses <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Sim1" target="_blank">[32]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Hayhow1" target="_blank">[38]</a>. MAXALT = 600 m, MINHEATH = 20.0 ha, PMF = 1.0, JMmort = 64% and GMBIT = 2.</p

Regional boundaries in the model.

<p>(A) Regional boundaries in the initialisation of the hen harrier population; (B) Regional boundaries used in counting numbers of breeding pairs. The numbers and colours correspond to region names as follows: 0– Shetland; 1– Orkney; 2– Hebrides; 3– North Highlands; 4– West Highlands; 5– East Highlands; 6– Southern Uplands; 7– England (census breeding pair counts only); 8– Wales (census breeding pair counts only); 9– All of England (includes area of ‘7’); 10– All of Wales (includes area of ‘8’).</p

Variables for the bird, cell, population and landscape entities in the individual-based hen harrier model.

<p>Variables for the bird, cell, population and landscape entities in the individual-based hen harrier model.</p

Spatial patterns in hen harrier population growth, 1989–2030.

<p>Average densities of simulated pairs attempting to breed in each 10 km by 10 km square on the landscape for the baseline scenario, for the years 1989, 1998, 2004, 2010, 2013 and 2030. Average density is calculated as the average occupancy of a cell across 20 replicate simulations, averaged across all 100 cells in the square. For example, an average density of 0.01 indicates that, on average, 1 out of 100 cells are occupied in the given year in any given replicate of the scenario. Black lines denote region boundaries. MAXALT = 600 m, MINHEATH = 20.0 ha, PMF = 1.0, JMmort = 64% and GMBIT = 2. For region names corresponding to numbers, see legend of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone-0112492-g002" target="_blank">Figure 2</a>.</p

Parameters and their default values in the individual-based hen harrier model.

a<p>The search area dimensions are based on expert opinion and chosen (along with the natal KDIST parameter values) to produce dispersal kernels matching, as closely as possible, reported natal dispersal distances (a data set partially overlapping with the raw data for <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Etheridge1" target="_blank">[26]</a> Table 11); see section 2.5 of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#s2" target="_blank">Methods</a> (but also see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Arroyo2" target="_blank">[37]</a>).</p>b<p>These were based on expert judgement and set to reflect the fact that hen harriers tend to disperse less far after breeding failure than from the natal location, and that males tend to disperse further than females.</p>c<p>These values were set to allow for the rare extremely long distance dispersers as recorded in (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Etheridge1" target="_blank">[26]</a> Table 11).</p>d<p>PBREED1F was set to be higher than values in (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Etheridge1" target="_blank">[26]</a> Table 10; 68%) because in the model some females that should breed fail to find a mate.</p>e<p>The value of 80% (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Etheridge1" target="_blank">[26]</a> Table 8) was adjusted to account for the fact that we model killing of nesting females separately.</p>f<p>Assumed to be equal to the value for females.</p>g<p>Table 14 (other moorland).</p>h<p>p. 1092.</p>i<p>Additional annual female mortality due to persecution.</p>j<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Etheridge1" target="_blank">[26]</a> p. 1098 suggested that additional mortality of females nesting on grouse moors is approximately 60%; our estimates are slightly conservative and scaled according to the level of heather burning observed (see section 3.2 of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#s2" target="_blank">Methods</a> (<i>Input data</i>)).</p><p>Parameters and their default values in the individual-based hen harrier model.</p

Simulated regional breeding population growth between 1989 and 2030.

<p>The mean (± standard error) of the annual number of breeding pairs of hen harriers averaged across twenty replicate simulations. “Breeding pair” refers to a male and a female in a single territory which attempt to breed, whether successful or not. Crosses joined with lines denote mean values while dashed lines indicate SE boundaries. Grey circles denote the estimates and the grey error bars indicate the range of the 95% confidence intervals from the censuses <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Sim1" target="_blank">[32]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Hayhow1" target="_blank">[38]</a>. MAXALT = 600 m, MINHEATH = 20.0 ha, PMF = 1.0, JMmort = 64% and GMBIT = 2. Note the different y-axis scales for North and West Highlands. For England and Wales, model results are presented for cells within the limits of the 2004 census only (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone.0112492-Sim1" target="_blank">[32]</a><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112492#pone-0112492-g002" target="_blank">Figure 2</a>).</p

Elasticity of the simulated model output in selected years to five model parameters, in grouse moor, other habitat and overall.

a<p>Only for the overall population.</p><p>Elasticity of the simulated model output in selected years to five model parameters, in grouse moor, other habitat and overall.</p