{"id":4645,"date":"2021-12-01T09:13:34","date_gmt":"2021-12-01T07:13:34","guid":{"rendered":"https:\/\/blogs.sun.ac.za\/cib\/?p=4645"},"modified":"2021-12-01T09:13:34","modified_gmt":"2021-12-01T07:13:34","slug":"context-matters-in-biological-invasions-a-new-synthesis-paper-shows-how-to-deal-with-it","status":"publish","type":"post","link":"https:\/\/blogs.sun.ac.za\/cib\/context-matters-in-biological-invasions-a-new-synthesis-paper-shows-how-to-deal-with-it\/","title":{"rendered":"Context matters in biological invasions \u2014 a new synthesis paper shows how to deal with it"},"content":{"rendered":"<p>Whether an organism will become invasive and have impacts depends on how organisms were moved around, the type of organism, and the recipient environment (Py\u0161ek et al. 2020). Or to put another way, if asked whether an organism is likely to become a harmful invader, ecologists are likely to answer \u2018<em>Well\u2026 it depends.<\/em>\u2019 This reflects the wonderful variety and complexity of nature and people, but such a response can be enormously frustrating to policy makers and managers. They want a clear answer to the question \u2018<em>What should we do?<\/em>\u2019<\/p>\n<p>A new synthesis paper in<a href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0169534721002585?via%3Dihub\" target=\"_blank\" rel=\"noopener\"><em> Trends in Ecology and Evolution <\/em>(TREE)<\/a>, co-authored by C\u2219I\u2219B Core Team member John Wilson and C\u2219I\u2219B Associate Petr Py\u0161ek, provides advice as to how this can be answered in a scientifically robust way, \u2018\u2026<em>it depends on how the data were collected and interpreted and on these specific factors&#8230;<\/em>\u2019<\/p>\n<p>The importance of context has been long debated in invasion science, and increasingly the term \u2018<em>context dependent<\/em>\u2019 has been used as a \u00a0shorthand for either \u2018<em>We do not know<\/em>\u2019 or \u2018<em>We have shown a factor to be important, but we recognise it is a bit more complicated than that<\/em>\u2019.<\/p>\n<p>In their TREE paper, the authors identified four different reasons why the results of a study vary with the context under which the study is performed.<\/p>\n<ul>\n<li>There is an <strong>interaction effect<\/strong>. This means there is a mechanistic interaction between a variable and the invasive organisms. They cite the case of giant bamboo, <em>Phyllostachys bambusoides<\/em>, an example cited in their TREE paper.\u00a0 Invasive populations in Japan show a positive relationship with canopy cover in cold regions but a negative relationship in warm regions, owing to the interaction effects of light and temperature on bamboo occupancy (see Spake et al. 2021).<\/li>\n<li>There is a <strong>confounding factor<\/strong>. While it might appear from the data that there is a direct causal relationship, this is actually mediated by another (often unmeasured) factor. Therefore, if results are extrapolated to a different region where the confounder is no longer the same, then the relationship might not hold, and advice to managers will be misleading.<\/li>\n<li>How the relationship is defined also depends on the <strong>statistical tools <\/strong>used. Importantly this can both be due to overestimating the significance of a weak relationship and underestimating the potential importance of a relationship that is found to be \u2018not significant\u2019.<\/li>\n<li>Finally apparent context dependence can occur if <strong>different methods<\/strong> are used, and this is not properly addressed when different studies are compared.<\/li>\n<\/ul>\n<p><img fetchpriority=\"high\" decoding=\"async\" class=\" wp-image-4646 aligncenter\" src=\"https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-1-580x516.jpg\" alt=\"\" width=\"538\" height=\"479\" srcset=\"https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-1-580x516.jpg 580w, https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-1-940x836.jpg 940w, https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-1-768x683.jpg 768w, https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-1-1536x1367.jpg 1536w, https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-1.jpg 1551w\" sizes=\"(max-width: 538px) 100vw, 538px\" \/><\/p>\n<p>The paper elucidates each of these types of context dependence and proposes a flow diagram (see below) to assist in differentiating the different types and identifying what needs to be done to be confident that X really does depend on Y in a predictable way.<\/p>\n<p>It will not be possible to always address context dependence, but it is fundamental to invasion science.<\/p>\n<blockquote><p><em>&#8220;If you aren&#8217;t addressing context dependency you aren&#8217;t doing ecology<\/em>!&#8221; <em>(Prof. Luke Flory, University of Florida on Twitter <a href=\"https:\/\/mobile.twitter.com\/lflory\/status\/1455638192363761664\" target=\"_blank\" rel=\"noopener\">https:\/\/mobile.twitter.com\/lflory\/status\/1455638192363761664)<\/a><\/em><\/p><\/blockquote>\n<p>&nbsp;<\/p>\n<p><img decoding=\"async\" class=\"size-medium wp-image-4647 aligncenter\" src=\"https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-2-580x772.jpg\" alt=\"\" width=\"580\" height=\"772\" srcset=\"https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-2-580x772.jpg 580w, https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-2-940x1251.jpg 940w, https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-2-768x1022.jpg 768w, https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-2-1154x1536.jpg 1154w, https:\/\/blogs.sun.ac.za\/cib\/files\/2021\/11\/JW_TREE_Pic-2.jpg 1531w\" sizes=\"(max-width: 580px) 100vw, 580px\" \/><\/p>\n<h4><strong>Read the full paper<\/strong><\/h4>\n<p><a href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0169534721002585?via%3Dihub\" target=\"_blank\" rel=\"noopener\">Catford JA, Wilson JRU, Py\u0161ek P, Hulme PE, Duncan RP (2022) Addressing context dependence in ecology. <em>Trends in Ecology &amp; Evolution<\/em>. doi: 10.1016\/j.tree.2021.09.007<\/a><\/p>\n<p>For more information, contact John Wilson at <a href=\"mailto:Wilson,%20John%20[jrwilson@sun.ac.za]\" target=\"_blank\" rel=\"noopener\">jrwilson@sun.ac.za<\/a><\/p>\n<h4><strong>Further references<\/strong><\/h4>\n<p>Py\u0161ek P, Bacher S, K\u00fchn I, Novoa A, Catford JA, Hulme PE, Pergl J, Richardson DM, Wilson JRU, Blackburn TM (2020) MAcroecological Framework for Invasive Aliens (MAFIA): disentangling large-scale context dependence in biological invasions. <em>Neobiota<\/em> 62: 407\u2013462. <a href=\"https:\/\/doi.org\/10.3897\/neobiota.62.52787\" target=\"_blank\" rel=\"noopener\">https:\/\/doi.org\/10.3897\/neobiota.62.52787<\/a><\/p>\n<p>Spake R, Soga M, Catford JA, Eigenbrod F (2021) Applying the stress-gradient hypothesis to curb the spread of invasive bamboo. <em>Journal of Applied Ecology<\/em> 58: 1993-2003. <a href=\"https:\/\/besjournals.onlinelibrary.wiley.com\/doi\/10.1111\/1365-2664.13945\" target=\"_blank\" rel=\"noopener\">doi:10.1111\/1365-2664.13945<\/a><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A new synthesis paper by C\u2219I\u2219B Core Team member John Wilson and C\u2219I\u2219B Associate Petr Py\u0161ek, provides advice on how to address context dependency in invasion science.<\/p>\n","protected":false},"author":11009,"featured_media":4646,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"ocean_post_layout":"","ocean_both_sidebars_style":"","ocean_both_sidebars_content_width":0,"ocean_both_sidebars_sidebars_width":0,"ocean_sidebar":"","ocean_second_sidebar":"","ocean_disable_margins":"enable","ocean_add_body_class":"","ocean_shortcode_before_top_bar":"","ocean_shortcode_after_top_bar":"","ocean_shortcode_before_header":"","ocean_shortcode_after_header":"","ocean_has_shortcode":"","ocean_shortcode_after_title":"","ocean_shortcode_before_footer_widgets":"","ocean_shortcode_after_footer_widgets":"","ocean_shortcode_before_footer_bottom":"","ocean_shortcode_after_footer_bottom":"","ocean_display_top_bar":"default","ocean_display_header":"default","ocean_header_style":"","ocean_center_header_left_menu":"","ocean_custom_header_template":"","ocean_custom_logo":0,"ocean_custom_retina_logo":0,"ocean_custom_logo_max_width":0,"ocean_custom_logo_tablet_max_width":0,"ocean_custom_logo_mobile_max_width":0,"ocean_custom_logo_max_height":0,"ocean_custom_logo_tablet_max_height":0,"ocean_custom_logo_mobile_max_height":0,"ocean_header_custom_menu":"","ocean_menu_typo_font_family":"","ocean_menu_typo_font_subset":"","ocean_menu_typo_font_size":0,"ocean_menu_typo_font_size_tablet":0,"ocean_menu_typo_font_size_mobile":0,"ocean_menu_typo_font_size_unit":"px","ocean_menu_typo_font_weight":"","ocean_menu_typo_font_weight_tablet":"","ocean_menu_typo_font_weight_mobile":"","ocean_menu_typo_transform":"","ocean_menu_typo_transform_tablet":"","ocean_menu_typo_transform_mobile":"","ocean_menu_typo_line_height":0,"ocean_menu_typo_line_height_tablet":0,"ocean_menu_typo_line_height_mobile":0,"ocean_menu_typo_line_height_unit":"","ocean_menu_typo_spacing":0,"ocean_menu_typo_spacing_tablet":0,"ocean_menu_typo_spacing_mobile":0,"ocean_menu_typo_spacing_unit":"","ocean_menu_link_color":"","ocean_menu_link_color_hover":"","ocean_menu_link_color_active":"","ocean_menu_link_background":"","ocean_menu_link_hover_background":"","ocean_menu_link_active_background":"","ocean_menu_social_links_bg":"","ocean_menu_social_hover_links_bg":"","ocean_menu_social_links_color":"","ocean_menu_social_hover_links_color":"","ocean_disable_title":"default","ocean_disable_heading":"default","ocean_post_title":"","ocean_post_subheading":"","ocean_post_title_style":"","ocean_post_title_background_color":"","ocean_post_title_background":0,"ocean_post_title_bg_image_position":"","ocean_post_title_bg_image_attachment":"","ocean_post_title_bg_image_repeat":"","ocean_post_title_bg_image_size":"","ocean_post_title_height":0,"ocean_post_title_bg_overlay":0.5,"ocean_post_title_bg_overlay_color":"","ocean_disable_breadcrumbs":"default","ocean_breadcrumbs_color":"","ocean_breadcrumbs_separator_color":"","ocean_breadcrumbs_links_color":"","ocean_breadcrumbs_links_hover_color":"","ocean_display_footer_widgets":"default","ocean_display_footer_bottom":"default","ocean_custom_footer_template":"","ocean_post_oembed":"","ocean_post_self_hosted_media":"","ocean_post_video_embed":"","ocean_link_format":"","ocean_link_format_target":"self","ocean_quote_format":"","ocean_quote_format_link":"post","ocean_gallery_link_images":"off","ocean_gallery_id":[],"footnotes":""},"categories":[76056,64267],"tags":[76363,76364,76365,76366,71746,76367],"class_list":["post-4645","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-2021-highlighted-paper","category-highlighted-paper","tag-apparent-mechanistic-context-dependence","tag-contingency-higher-order-interactions","tag-ecological-interaction-effects","tag-experimental-design-statistics","tag-invasive-alien-species","tag-multiple-stressors-global-environmental-change-factors","entry","has-media"],"acf":[],"_links":{"self":[{"href":"https:\/\/blogs.sun.ac.za\/cib\/wp-json\/wp\/v2\/posts\/4645","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.sun.ac.za\/cib\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.sun.ac.za\/cib\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.sun.ac.za\/cib\/wp-json\/wp\/v2\/users\/11009"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.sun.ac.za\/cib\/wp-json\/wp\/v2\/comments?post=4645"}],"version-history":[{"count":7,"href":"https:\/\/blogs.sun.ac.za\/cib\/wp-json\/wp\/v2\/posts\/4645\/revisions"}],"predecessor-version":[{"id":4661,"href":"https:\/\/blogs.sun.ac.za\/cib\/wp-json\/wp\/v2\/posts\/4645\/revisions\/4661"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.sun.ac.za\/cib\/wp-json\/wp\/v2\/media\/4646"}],"wp:attachment":[{"href":"https:\/\/blogs.sun.ac.za\/cib\/wp-json\/wp\/v2\/media?parent=4645"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.sun.ac.za\/cib\/wp-json\/wp\/v2\/categories?post=4645"},{"taxonomy":"post_tag","embeddable":true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