11 research outputs found
Alternative models for the relative abundance of crested tits in juniper woodlands of Spain during winter, and results of multimodel inference using all predictor variables.
<p>Sample size is 26 juniper woodlands. X: variables included in the <i>a priori</i> models. Multimodel inference averages the first eight models with ΔAICc<4 using model weights (W<sub>i</sub>). Values presented for variables in multimodel inference are weighted averages of standardized beta regression coefficients obtained in generalized linear models considering model weights W<sub>i</sub> (beta values inform about the magnitude and sign of the partial relationships of the predictor variables with the relative abundance of crested tits). AICc: AIC corrected for small sample sizes. ΣW<sub>i</sub>: sum of Akaike weights for each variable considering those models where they were selected in AIC multimodel inference. K: number of predictor variables+intercept. Habitat variables (HB): hJ - average height of juniper trees; #J - number of juniper trees per 5,000 m<sup>2</sup>. Tm: minimum night temperature. Food variables: AR - arthropod abundance; FR - fruit abundance index. DL: day length at winter solstice; Landscape variables: ALT - altitude; L1 - multivariate gradient of increasing cover of agricultural landscape around each juniper woodland plot; L2 - multivariate gradient of increasing cover of coniferous and mixed forests dominated by <i>Pinus nigra</i>; L3 - multivariate gradient of increasing cover of holm oak, <i>Quercus ilex</i>, forests.</p
Characteristics of the ten experimental feeders.
<p>Temperature and light intensity refer to those registered during the 14 sampling days. The dashed line divides feeders included in ‘near’ and ‘far’ categories. Feeding time and visits to feeders are cumulative numbers for all 38 birds, measured in seconds of feeder use and number of visits per 10 hours of recording time, respectively.</p
Mean, standard deviation (sd) and range (min/max) of study variables in 26 juniper woodlands in Spain in winters 2009–2010 and 2010–2011.
<p>Relative abundance of tits refers to the mean number of birds counted in four censuses without detection distance limit (two censuses per winter). Values for temperatures are averages for 77 days (1 December to 15 February) in two consecutive winters. Tree height and abundances of fruits and arthropods are estimated in each juniper woodland as the average of several samples (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032733#s2" target="_blank">Methods</a> for more details). R<sup>2</sup>: square of the correlation between day length at winter solstice and each variable (**: <i>p</i><0.01; *: <i>p</i><0.05; no correlation was significant after applying Bonferroni correction).</p
Feeding time (seconds of feeder use per 10 hours of recording time) spent by individual birds at each feeder (see characteristics in Table 1).
<p>Only 38 individual birds for which at least 10 visits to feeders were obtained are shown (i.e., those included in the statistical analyses). Individuals are numbered within specie. Cc: <i>Cyanistes caeruleus</i>, Lc: <i>Lophophanes cristatus</i>, Se: <i>Sitta europaea</i>, Pm: <i>Parus major</i>, Pa: <i>Periparus ater.</i></p
Figure 2
<p>Partial residual plots illustrating the influence of day length at winter solstice (a), average height of juniper trees (b) and availability of ripe juniper fruits (c) on the relative abundance of crested tits in Spanish juniper woodlands during winter. N = 26 woodlands.</p
Distribution of Spanish juniper woodlands and the study localities.
<p>Grey areas depict areas over 1000 m above sea level on the Iberian Peninsula and black patches show the actual distribution of the Spanish juniper woodlands. Boxes show the spatial distribution of the study localities (black points) on the expanses of juniper woodlands (grey).</p
data Morelli et al. 2017 JAE
List of Cuculidae species used in this study, common names, parasite behavior, number of host species, breeding distribution range and evolutionary distinctiveness (ED) score. The number of hosts for each cuckoo species was obtained from a literature review (Davies 2000; Erritzøe et al. 2012; Yang et al. 2012). The breeding distribution range was obtained from IUCN (IUCN & BirdLife International 2017) and ED score was downloaded from Edge of Existence (Zoological Society of London 2008)
Prevalence and infection load of <i>Batrachochytrium dendrobatidis</i>.
<p>Prevalence (left) and infection load (right; in logarithm scale, GE, mean +/- SE) for populations of <i>Alytes obstetricans</i> tadpoles in six different sites throughout 12 months in each site. Monthly average minimum and maximum water temperature are shown in blue and red respectively.</p
Average minimum water temperature and infection load of <i>Batrachochytrium dendrobatidis</i>.
<p>Partial residual plot illustrating the influence of average minimum water temperature two days before tadpole sampling, on <i>Batrachochytrium dendrobatidis</i> infection load (in logarithm) of <i>Alytes obstetricans</i> tadpoles from six different sites. Sample size is 11 months for each site. The residual plot shows the relationship between minimum temperature and <i>Bd</i> load given that the other two independent variables are also in the model (see with temperature-2 days in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120237#pone.0120237.t001" target="_blank">Table 1</a>), therefore, partialling out their effects. The inner panel shows the modeled relationship between <i>Bd</i> load (average number of zoospores per tadpole) and average minimum temperature two days before sampling.</p