MLXRoots2007

Root lengt

MLXResources2007

Soil N and moistur

The Effects of Experimental Irrigation on Plant Productivity, Insect Abundance and the Non-Breeding Season Performance of a Migratory Songbird

<div><p>Migratory bird populations are often limited by food during the non-breeding season. Correlative evidence suggests that food abundance on territories varies among years in relation to rainfall, which affects plant productivity and arthropod biomass. At the Font Hill Nature Preserve in Jamaica, we used an irrigation experiment to test the hypothesis that rainfall affects the condition of wintering American redstarts (<em>Setophaga ruticilla</em>) via intermediate effects on plant productivity and arthropod abundance. Experimental plots were irrigated in late February and early March to simulate a mid-season pulse of 200 mm of rain. Irrigation maintained soil moisture levels near saturation and had immediate effects on plant productivity. Cumulative leaf abscission over the dry season was 50% lower on experimental plots resulting in greater canopy cover, and we observed significantly higher ground level shoot growth and the flushing of new leaves on about 58% of logwood (<em>Haematoxylon campechianum</em>) individuals. Arthropod biomass was 1.5 times higher on irrigated plots, but there was considerable inter-plot variability within a treatment and a strong seasonal decline in biomass. Consequently, we found no significant effect of irrigation on arthropod abundance or redstart condition. We suspect that the lack of an irrigation effect for taxa higher on the trophic chain was due to the small spatial scale of the treatment relative to the scale at which these taxa operate. Although redstart condition was not affected, we did observe turnover from subordinate to dominant territorial individuals on experimental plots suggesting a perceived difference in habitat quality that influenced individual behavior.</p> </div

Effects of experimental irrigation on dry season scrub habitat at the Font Hill Nature Preserve, Jamaica.

<p>A control plot is shown on the left and an irrigated plot on the right. Photos were taken in late March after the second round of irrigation.</p

Soil moisture conditions on irrigated and control plots at the Font Hill Nature Preserve, Jamaica.

<p>Soil moisture is measured in centibars (Kpa) of soil suction with lower values indicating moister conditions. Irrigation on the plot took place from 19 February to 27 February and 11 March to 19 March (represented by the two black bars under the x-axis).</p

Nitrogen-15 isotope values for four taxonomic groups on control and irrigated plots at Font Hill, Jamaica.

<p>Values include the mean and standard error with the sample size in brackets. Stars indicate significant differences (p<0.05).</p

Cumulative leaf fall on control and irrigation plots. Leaves were collected weakly in 0.5 m² traps and values have been scaled to grams/m².

<p> a and b represent the onset of irrigation for experimental sites 1 and 2 respectively.</p

Node-dated phylogeny of 530 species included in T. gondii analysis.

The maximum clade credibility topology of 10,000 trees is shown. The inner panel depicts the species-level T. gondii prevalence over all available studies. The outer panel identifies the taxonomic families.</p

Distribution of study sites included in the global analysis of <i>Toxoplasma gondii</i> prevalence data for domestic animals and free-ranging wildlife.

The country-level sampling intensity in terms of number of individuals sampled is shown for wildlife (blue) and domestic animals (green). Countries for which T. gondii prevalence data was not found within the scope of our search are shown in grey. Basemap was made with Natural Earth (https://www.naturalearthdata.com).</p

Reference list of publications for which <i>T</i>. <i>gondii</i> prevalence data was available for free-ranging wild and domesticated mammal populations.

Reference list of publications for which T. gondii prevalence data was available for free-ranging wild and domesticated mammal populations.</p