University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln USGS Staff -- ubP lished Research US Geological Survey 4-28-2017 Sensitivity of mangrove range limits to climate variability Kyle C. Cavanaugh Department of Geography, University of California, [email protected] Michael J. Osland U.S. Geological Survey, Wetland and Aquatic Research Center Remi Bardou Department of Geography, University of California Gustavo Hinojosa-Arango Academia de Biodiversidad, Centro Interdisciplinario de Investigacion para el Desarrollo Integral Regional Unidad Oaxaca (CIIDIR-IPN) Juan M. Lopez-Vivas Programa de Investigacion en Botanica Marina, Departamento Academico de Ciencias Marinas y Costeras, Universidad See next page for additional authors Follow this and additional works at: http://digitalcommons.unl.edu/usgsstaffpub Part of the Geology Commons, Oceanography and Atmospheric Sciences and Meteorology Commons, Other Earth Sciences Commons, and the Other Environmental Sciences Commons Cavanaugh, Kyle C.; Osland, Michael J.; Bardou, Remi; Hinojosa-Arango, Gustavo; Lopez-Vivas, Juan M.; Parker, John D.; and Rovai, Andre S., "Sensitivity of mangrove range limits to climate variability" (2017). USGS Staff -- Published Research. 1041. http://digitalcommons.unl.edu/usgsstaffpub/1041 This Article is brought to you for free and open access by the US Geological Survey at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USGS Staff -- ubP lished Research by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors Kyle C. Cavanaugh, Michael J. Osland, Remi Bardou, Gustavo Hinojosa-Arango, Juan M. Lopez-Vivas, John D. Parker, and Andre S. Rovai This article is available at DigitalCommons@University of Nebraska - Lincoln: http://digitalcommons.unl.edu/usgsstaffpub/1041 Received: 28 April 2017 | Revised: 5 March 2018 | Accepted: 14 March 2018 DOI: 10.1111/geb.12751 RESEARCH PAPER Sensitivity of mangrove range limits to climate variability Kyle C. Cavanaugh1 | Michael J. Osland2 | Remi Bardou1 | Gustavo Hinojosa-Arango3 | Juan M. Lopez-Vivas 4 | John D. Parker5 | Andre S. Rovai6,7 1Department of Geography, University of California, Los Angeles, Los Angeles, Abstract California Aim: Correlative distribution models have been used to identify potential climatic controls of man- 2U.S. Geological Survey, Wetland and grove range limits, but there is still uncertainty about the relative importance of these factors Aquatic Research Center, Lafayette, Louisiana across different regions. To provide insights into the strength of climatic control of different man- 3Academia de Biodiversidad, Centro grove range limits, we tested whether temporal variability in mangrove abundance increases near Interdisciplinario de Investigacion para el range limits and whether this variability is correlated with climatic factors thought to control large- Desarrollo Integral Regional Unidad Oaxaca scale mangrove distributions. (CIIDIR-IPN), Santa Cruz Xoxocotlan, Oaxaca, Mexico Location: North and South America. 4Programa de Investigacion en Botanica Time period: 1984–2011. Marina, Departamento Academico de Ciencias Marinas y Costeras, Universidad Major taxa studied: Avicennia germinans, Avicennia schuaeriana, Rhizophora mangle, Laguncularia Autonoma de Baja California Sur, La Paz, Baja California Sur, Mexico racemosa. 5Smithsonian Environmental Research Methods: We characterized temporal variability in the enhanced vegetation index (EVI) at man- Center, Smithsonian Institution, Edgewater, grove range limits using Landsat satellite imagery collected between 1984–2011. We Maryland characterized greening trends at each range limit, examined variability in EVI along latitudinal gra- 6Department of Oceanography and Coastal Sciences, College of the Coast and dients near each range limit, and assessed correlations between changes in EVI and temperature Environment, Louisiana State University, and precipitation. Baton Rouge, Louisiana Results: Spatial variability in mean EVI was generally correlated with temperature and precipita- 7Programa de Pos-Graduaç ao~ em Oceanografia, Centro de Filosofia e Ciencias^ tion, but the relationships were region specific. Greening trends were most pronounced at range Humanas, Florianopolis, Santa Catarina, limits in eastern North America. In these regions variability in EVI increased toward the range limit Brazil and was sensitive to climatic factors. In contrast, EVI at range limits on the Pacific coast of North Correspondence America and both coasts of South America was relatively stable and less sensitive to climatic Kyle C. Cavanaugh, Department of variability. Geography, 1255 Bunche Hall, University of California, Los Angeles, 90095. Main conclusions: Our results suggest that range limits in eastern North America are strongly con- Email: [email protected] trolled by climate factors. Mangrove expansion in response to future warming is expected to be rapid in regions that are highly sensitive to climate variability (e.g. eastern North America), but the Funding information National Aeronautics and Space response in other range limits (e.g. South America) is likely to be more complex and modulated by Administration, Grant/Award Number: additional factors such as dispersal limitation, habitat constraints, and/or changing climatic means NNX11AO94G; New Investigator Program, rather than just extremes. Grant/Award Number: NNX16AN04G; National Science Foundation, Grant/Award Number: EF 1065821; University of KEYWORDS California Institute for Mexico and the climatic drivers, distribution, EVI, Landsat, mangrove forests, range limit United States; Louisiana Sea Grant College; USGS Ecosystems Mission Area; Land Change Science Climate R&D Program Editor: Naia Morueta-Holme Global Ecol Biogeogr. 2018;27:925–935. wileyonlinelibrary.com/journal/geb VC 2018 John Wiley & Sons Ltd | 925 926 | CAVANAUGH ET AL. 1 | INTRODUCTION Climate change, particularly global increases in temperature, have already led to poleward shifts in the distributions of many species (Par- mesan & Yohe, 2003), with especially apparent impacts at the bounda- ries of major biomes. For example, shrubs and trees have expanded northward in tundra ecosystems across the Arctic in response to recent warming (Tape, Sturm, & Racine, 2006). Similarly, in marine ecosystems around the world tropical herbivores have expanded their range into temperate waters, leading to a loss of habitat-forming species and dra- matic community phase shifts (Verges et al., 2014). These range shifts can have large impacts on the structure and functioning of ecosystems, FIGURE 1 Conceptual diagram of enhanced vegetation index (EVI) pointing to a need to better understand the processes that control spe- patterns near different types of range limits. A: Range limit is near cies’ range limits. climatic tolerance with high climatic variation and so climatic Correlative distribution modelling has become one of the most variability drives variability in plant performance, for example ‘USA common approaches for gaining insight into the processes that control – Atlantic’ in Figure 6. B: Range limit is not yet at climatic species’ distributions and for predicting changes to those distributions tolerance due to dispersal limitation and/or habitat constraints. As (Elith & Leathwick, 2009). These types of models are based on the sta- a result, plant performance is relatively insensitive to climate variability, for example ‘Peru’ in Figure 6. C: Range limit is near tistical association between species occurrences and environmental or climatic tolerance with low climatic variation. Plant performance is climate data. These models are flexible in that they utilize readily avail- sensitive to climatic variability, but climatic variability is low, for able data and are relatively simple to implement. However, correlative example ‘Mexico – Gulf of California’ in Figure 6 distribution models assume that a species is in equilibrium with its envi- ronment, which may not be the case during rapid climate change or fisheries, filtering of sediments and nutrients, elevation maintenance when a range limit is controlled by dispersal limitation or biotic interac- and erosion avoidance, and carbon sequestration and storage (Ewel, tions (Kearney & Porter, 2009). Twilley, & Ong, 1998). Mangroves are largely found between the lati- Data on the temporal fluctuations in abundance or performance of tudes of c. 308Nandc. 408S; however the latitude of the poleward a species near its range limit can provide additional insight into the range limit varies among regions, as do the climatic conditions at those processes that control its distribution, and thus be used to test predic- range limits (Osland, Feher, et al., 2017; Quisthoudt et al., 2012). tions of correlative distribution models. If a range limit is controlled by Previous work has provided valuable insight into the drivers of an abiotic environmental or climatic factor, then we would expect tem- mangrove range limitation by comparing current mangrove distribu- poral variability in that factor to correlate with variability of range limit tions to climatic variables. These studies range from descriptions of cli- populations. More generally, if a range limit is set by climatic factors, matic conditions at various poleward range limits (Duke, Ball, & Ellison, then population abundance or performance at the range edge, where 1998; Quisthoudt et al., 2012; Saenger, 2002) to models that relate the species