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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Wilfred J Previant</dc:contributor>
  <dc:contributor>John B. Bradford</dc:contributor>
  <dc:contributor>Linda M Nagel</dc:contributor>
  <dc:creator>Christopher E. Looney</dc:creator>
  <dc:date>2021</dc:date>
  <dc:description>&lt;ol class=""&gt;&lt;li&gt;Tree-species mixture effects (e.g. complementarity and facilitation) have been found to increase individual-tree productivity, lessen mortality and improve recruitment in forests worldwide. By promoting more efficient and complete resource use, mixture effects may also lessen individual-tree-level water stress, thus improving drought resistance. We investigated the influence of mixture effects on tree productivity, mortality and recruitment across broad compositional and moisture gradients in high-elevation Interior West US mixed-conifer communities, where&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Populus tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;(trembling aspen) is the major contributor to functional diversity. Our goal was to provide a more complete scientific foundation for managing these drought-prone, fire-excluded systems under an uncertain climate.&lt;/li&gt;&lt;li&gt;We used landscape-scale national forest inventory data to examine mixture effects on&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and the major associated conifer species,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Pseudotsuga menziesii&lt;/i&gt;,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Pinus contorta&lt;/i&gt;,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Abies lasiocarpa&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Picea engelmannii&lt;/i&gt;. Using generalized linear mixed modelling, we isolated the influences of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;relative density and climate on tree-level (stems ≥ 12.7&amp;nbsp;cm DBH) growth, mortality and stand-level recruitment (presence/absence of new trees). Cold-season precipitation (PPT) and warm-season vapour pressure deficit (VPD) served to represent soil moisture supply and demand, respectively.&lt;/li&gt;&lt;li&gt;&lt;i&gt;Populus tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;growth declined as interspecific density increased. In contrast,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Pinus contorta&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;A. lasiocarpa&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;growth increased with&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;density. For all species except&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;A. lasiocarpa&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. menziesii,&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;growth increased under higher PPT and VPD.&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Populus tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;mortality increased under high VPD but not with interspecific relative density. We found limited evidence that&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;A. lasiocarpa&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;mortality decreased as&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;density increased.&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Populus tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;recruitment declined steeply above 25% interspecific relative density. We found a decline in conifer recruitment odds as&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;density increased, ranging from strong in&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. contorta&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;to insubstantial in&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. engelmannii&lt;/i&gt;.&lt;/li&gt;&lt;li&gt;&lt;i&gt;Synthesis&lt;/i&gt;. Our findings have implications for sustaining mixed-conifer communities impacted by climate change and historical fire exclusion. Mixtures of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and conifers may improve conifer growth while adversely impacting&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;growth relative to pure stands. Higher conifer productivity combined with lower&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;P. tremuloides&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;recruitment at high conifer relative density may accelerate succession.&lt;/li&gt;&lt;/ol&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1111/1365-2745.13709</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>British Ecological Society</dc:publisher>
  <dc:title>Species mixture effects and climate influence growth, recruitment and mortality in Interior West USA Populus tremuloides-conifer communities</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>