Sensitivity of mangrove range limits to climate variability

Aim: Correlative distribution models have been used to identify potential climatic controls of mangrove range limits, but there is still uncertainty about the relative importance of these factors across different regions. To provide insights into the strength of climatic control of different mangrove range limits, we tested whether temporal variability in mangrove abundance increases near range limits and whether this variability is correlated with climatic factors thought to control large scale mangrove distributions. Location: North and South America. Time period: 1984–2011. Major taxa studied: Avicennia germinans, Avicennia schuaeriana, Rhizophora mangle, Laguncularia racemosa. Methods: We characterized temporal variability in the enhanced vegetation index (EVI) at mangrove range limits using Landsat satellite imagery collected between 1984–2011. We characterized greening trends at each range limit, examined variability in EVI along latitudinal gradients near each range limit, and assessed correlations between changes in EVI and temperature and precipitation. Results: Spatial variability in mean EVI was generally correlated with temperature and precipitation, but the relationships were region specific. Greening trends were most pronounced at range limits in eastern North America. In these regions variability in EVI increased toward the range limit and was sensitive to climatic factors. In contrast, EVI at range limits on the Pacific coast of North America and both coasts of South America was relatively stable and less sensitive to climatic variability. Main conclusions: Our results suggest that range limits in eastern North America are strongly controlled 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 response in other range limits (e.g. South America) is likely to be more complex and modulated by additional factors such as dispersal limitation, habitat constraints, and/or changing climatic means rather than just extremes

Foliar water uptake by coastal wetland plants: A novel water acquisition mechanism in arid and humid subtropical mangroves

Climate change alters freshwater availability in many ecosystems leading to shifts in distributions for many plants. Despite living exclusively in intertidal, saline environments, mangroves rely on non-saline water to maintain plant productivity. However, several mangrove species persist in arid environments where non-saline water from rain and groundwater sources are limited. Under these conditions, foliar water uptake from fog and mist may be an important water acquisition strategy. We conducted a field experiment in arid Baja California Sur, Mexico along with a controlled mist chamber experiment (using seedlings sourced from humid subtropical region, Florida, USA) to show that three co-occurring, neotropical mangrove species, Avicennia germinans, Laguncularia racemosa and Rhizophora mangle, growing in both arid and humid environments can access water condensed on their leaves. Foliar water uptake was greatest in A. germinans and lowest in R. mangle, possibly reflecting leaf traits associated with species-specific water balance strategies. In our field misting experiment, the contribution of foliar water uptake was higher in A. germinans (32 ± 2%) than L. racemosa (26 ± 2%) and R. mangle (16 ± 1%). Foliar water uptake also varied across locations for L. racemosa and R. mangle, with declining uptake towards both species’ northern range limits in Baja California Sur, suggesting the distribution patterns of arid-zone mangroves may be affected by species-specific spatial variation in foliar water use. Within species, foliar water use was comparable across field and controlled experiments irrespective of source population (Baja California Sur vs. Florida), suggesting foliar water uptake is not an arid-zone adaptation, and is instead used as a supplemental water balance strategy in arid and humid neotropical mangroves. Synthesis. Our findings indicate mangroves have the potential to access atmospheric water, such as rain, dew and sea fog, through their leaves to offset soil water deficits. Variation in foliar water use across these three neotropical mangrove species may influence mangrove species distributions across arid-zone and pseudo-drought (highly saline) environments, with implications for mangrove response to climate change

The Effect of Climate Change and Anthropogenic Activities on Mangrove Ecosystems

Mangroves are critical tropical coastal ecosystems and provide essential ecological and societal services. Mangroves have been rapidly changing over the last fifty years, and geospatial technologies provide a tool to measure such changes around the world. As a response to climate change and rising temperatures, mangroves have been encroaching into salt marshes at many mangrove-salt marsh ecotones in sub-tropical areas, rapidly shifting their distributions poleward. Although mangroves have faced substantial degradation and deforestation due to human activity, we have seen a rise in anthropological efforts towards their preservation and reforestation in recent years. This dissertation examines both climatic and anthropogenic drivers of change for mangrove ecosystems, using a combination of remote sensing, climate modeling, and manipulative experiments. First, we investigate mangrove range limit dynamics on the Atlantic and Pacific coasts of North America, where the same three species of mangroves are found. Using gridded climate data, remote sensing and manipulative experiments, we compared the realized and fundamental niches of the Atlantic and Pacific mangroves, and found notably different responses to environmental conditions, resulting in contrasting range dynamics. We then focused specifically on the Pacific range limit, where further manipulative experiments on cold water temperatures and aridity highlighted the fact that mangroves’ response to changes in climate is highly species- and location-specific. Therefore, aspects particular to each range population must be taken into consideration to best understand and predict mangrove response to climate change. Lastly, we focused on anthropogenic impacts on mangrove ecosystems. Using the island of Madagascar - a major biodiversity hotspot - as a case study, we conducted a remote sensing analysis of mangrove dynamics over fifty years. Results show that mangroves have faced considerable loss. However, recent awareness arising over the last twenty years has led to better conservation and preservation efforts, resulting in an increase in overall mangrove cover during this period

Sensitivity of mangrove range limits to climate variability

Aim: Correlative distribution models have been used to identify potential climatic controls of mangrove range limits, but there is still uncertainty about the relative importance of these factors across different regions. To provide insights into the strength of climatic control of different mangrove range limits, we tested whether temporal variability in mangrove abundance increases near range limits and whether this variability is correlated with climatic factors thought to control large scale mangrove distributions. Location: North and South America. Time period: 1984–2011. Major taxa studied: Avicennia germinans, Avicennia schuaeriana, Rhizophora mangle, Laguncularia racemosa. Methods: We characterized temporal variability in the enhanced vegetation index (EVI) at mangrove range limits using Landsat satellite imagery collected between 1984–2011. We characterized greening trends at each range limit, examined variability in EVI along latitudinal gradients near each range limit, and assessed correlations between changes in EVI and temperature and precipitation. Results: Spatial variability in mean EVI was generally correlated with temperature and precipitation, but the relationships were region specific. Greening trends were most pronounced at range limits in eastern North America. In these regions variability in EVI increased toward the range limit and was sensitive to climatic factors. In contrast, EVI at range limits on the Pacific coast of North America and both coasts of South America was relatively stable and less sensitive to climatic variability. Main conclusions: Our results suggest that range limits in eastern North America are strongly controlled 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 response in other range limits (e.g. South America) is likely to be more complex and modulated by additional factors such as dispersal limitation, habitat constraints, and/or changing climatic means rather than just extremes

Consensus Recommendations for the Use of Simulation in Therapeutic Patient Education.

peer reviewedINTRODUCTION: Simulation is rarely used to help individuals with chronic diseases develop skills. The aim of the study was to provide recommendations for the use of simulation in therapeutic patient education (S-TPE). METHODS: Expert consensus was achieved with the participation of the following 3 groups of experts: (a) expert patients and caregivers; (b) health professionals specialized in therapeutic patient education (TPE); and (c) simulation experts. Each expert received a list of questions by e-mail in 3 iterations. The synthesis of the 2 first questionnaires resulted in 34 first recommendations voted during the consensus conference meeting. Each recommendation was subject to an extensive literature review. The quality of the evidence and the strength of the recommendations were assessed through the evaluation, development, and evaluation criteria categories (GRADE criteria). The third questionnaire selected and illustrated recommendations more specific to the use of S-TPE. RESULTS: At the end of the process, the experts identified 26 recommendations specific to the use of S-TPE. They proposed examples of skills in different diseases and stressed the importance of adapting the conditions of use (location, equipment, time of the care) to the circumstances of the patient learner and skills to be developed. Experts should exercise great caution as this technique presents ethical considerations related to patient care. CONCLUSIONS: These recommendations underline the fact that simulation could bring added value to TPE. They provide a framework and examples for the experimental use of simulation in TPE. Research into feasibility and acceptability is needed