Carbon Stocks of Tropical Coastal Wetlands within the Karstic Landscape of the Mexican Caribbean

Coastal wetlands can have exceptionally large carbon (C) stocks and their protection and restoration would constitute an effective mitigation strategy to climate change. Inclusion of coastal ecosystems in mitigation strategies requires quantification of carbon stocks in order to calculate emissions or sequestration through time. In this study, we quantified the ecosystem C stocks of coastal wetlands of the Sian Ka'an Biosphere Reserve (SKBR) in the Yucatan Peninsula, Mexico. We stratified the SKBR into different vegetation types (tall, medium and dwarf mangroves, and marshes), and examined relationships of environmental variables with C stocks. At nine sites within SKBR, we quantified ecosystem C stocks through measurement of above and belowground biomass, downed wood, and soil C. Additionally, we measured nitrogen (N) and phosphorus (P) from the soil and interstitial salinity. Tall mangroves had the highest C stocks (987 ± 338 Mg ha⁻¹) followed by medium mangroves (623 ± 41 Mg ha⁻¹), dwarf mangroves (381 ± 52 Mg ha⁻¹) and marshes (177 ±73 Mg ha⁻¹). At all sites, soil C comprised the majority of the ecosystem C stocks (78-99%). Highest C stocks were measured in soils that were relatively low in salinity, high in P and low in N: P, suggesting that P limits C sequestration and accumulation potential. In this karstic area, coastal wetlands, especially mangroves, are important C stocks. At the landscape scale, the coastal wetlands of Sian Ka'an covering approximate to ≈172,176 ha may store 43.2 to 58.0 million Mg of C.Keywords: Ignition, Sea level, Mangrove forests, Enrichment, Organic matter, Florida, Biomass, Sediments, Nutrient dynamics, Brazilian AmazonKeywords: Ignition, Sea level, Mangrove forests, Enrichment, Organic matter, Florida, Biomass, Sediments, Nutrient dynamics, Brazilian Amazo

Carbon stocks of tropical coastal wetlands within the karstic landscape of the Mexican Caribbean.

Coastal wetlands can have exceptionally large carbon (C) stocks and their protection and restoration would constitute an effective mitigation strategy to climate change. Inclusion of coastal ecosystems in mitigation strategies requires quantification of carbon stocks in order to calculate emissions or sequestration through time. In this study, we quantified the ecosystem C stocks of coastal wetlands of the Sian Ka'an Biosphere Reserve (SKBR) in the Yucatan Peninsula, Mexico. We stratified the SKBR into different vegetation types (tall, medium and dwarf mangroves, and marshes), and examined relationships of environmental variables with C stocks. At nine sites within SKBR, we quantified ecosystem C stocks through measurement of above and belowground biomass, downed wood, and soil C. Additionally, we measured nitrogen (N) and phosphorus (P) from the soil and interstitial salinity. Tall mangroves had the highest C stocks (987±338 Mg ha(-1)) followed by medium mangroves (623±41 Mg ha(-1)), dwarf mangroves (381±52 Mg ha(-1)) and marshes (177±73 Mg ha(-1)). At all sites, soil C comprised the majority of the ecosystem C stocks (78-99%). Highest C stocks were measured in soils that were relatively low in salinity, high in P and low in N∶P, suggesting that P limits C sequestration and accumulation potential. In this karstic area, coastal wetlands, especially mangroves, are important C stocks. At the landscape scale, the coastal wetlands of Sian Ka'an covering ≈172,176 ha may store 43.2 to 58.0 million Mg of C

Escenarios sociopolíticos de las migraciones en Costa Rica y Colombia

El vínculo desarrollo - migración tiene diversas significaciones y comprende diferentes dimensiones, debido a las múltiples expresiones sociales, espaciales y temporales que las migraciones asumen. Son innumerables las evidencias de las transformaciones de las sociedades modernas, incluyendo su estructura, sistemas de distribución de recursos, formas identitarias y ordenamiento espacial, entre otras, que van de la mano de las migraciones

Ecosystem C stocks of coastal wetlands of Sian Ka'an Biosphere Reserve.

<p>The stocks are partitioned by A) aboveground (trees and down wood) and B) belowground (roots and soil) components. Lower case letters represent significant differences among sites and vegetation types (<i>n</i> = 6 per site, <i>p</i>≤0.0001). Note different scales between panel A and B.</p

Biomass (Mg ha⁻¹) and C stocks (Mg ha⁻¹) of downed wood for tall and medium mangroves.

<p>Sites were sampled within Sian Ka'an Biosphere Reserve, Mexico. Wood debris was calculated separately for small wood (diameter >2.5 and <7.5 cm), and large sound and large rotten wood (diameter >7.5 cm). Values are shown as mean (standard error).</p

Aboveground biomass, belowground biomass and total C stocks in vegetation (Mg ha⁻¹).

<p>Data are mean (standard error).</p><p>Nine sites were sampled (<i>n</i> = 6 plots per site) within coastal wetlands of Sian Ka'an Biosphere Reserve, Mexico. Values are shown as mean (standard error); n.a. = not available.</p>*<p>aboveground biomass of marsh.</p>**<p>aboveground biomass of marsh plus mangrove trees.</p>***<p>belowground biomass of mangrove trees.</p

Relationship among mangrove C stocks, interstitial salinity and surface soil phosphorus.

<p>Seven mangrove sites were sampled within Sian Ka'an Biosphere Reserve, Mexico; three dwarf, two medium, and two tall mangroves, one of the latter associated to a fresh water spring. Soil phosphorus (P) was measured in the 0–15 cm soil horizon. The correlations are significant with <i>R</i>² = 0.54, <i>F</i> = 31.3, <i>p</i><0.0001 and <i>R</i>² = 0.58, <i>F</i> = 26.3, <i>p</i><0.001 for C stocks against salinity and soil P, respectively. Collectively, salinity and soil P explained 86% of the variance in mangrove C stocks (<i>F</i> = 45.6, <i>p</i><0.001; VIF = 2.2).</p

Ecosystem C stocks (Mg ha⁻¹) of nine sites within different vegetation types of coastal wetlands of the Sian Ka'an Biosphere Reserve, Mexico.

<p>Values are shown as mean (standard error).</p

Allometric equations used to calculate aboveground and belowground biomass of mangrove trees.

<p>B = biomass; D_R = diameter above highest prop root; DBH = diameter at breast height; D₃₀ = diameter at 30 cm from the ground. Wood density values used for calculating belowground biomass were obtained from Zanne et al <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056569#pone.0056569-Zanne1" target="_blank">[36]</a>.</p

Area and C stock of coastal wetland vegetation of Sian Ka'an Biosphere Reserve, Mexico.

<p>Mangrove area (dwarf+medium+tall) was obtained from CONABIO <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056569#pone.0056569-CONABIO2" target="_blank">[23]</a>, “peten” vegetation area (tall mangroves associated with freshwater springs) and marsh area from INEGI maps (2005 and 2000, respectively) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056569#pone.0056569-INEGI1" target="_blank">[24]</a>.</p