Quantification of the Evaporation Rates from Six Types of Wetland Cover in Palo Verde National Park, Costa Rica

• Main Authors: César Dionisio Jiménez-Rodríguez, Catalina Esquivel-Vargas, Miriam Coenders-Gerrits, Mahmood Sasa-Marín
• Format: Article
• Language: English
• Published: MDPI AG 2019-04-01
• Series: Water
• Subjects: lysimeters; macrophytes; transpiration; marshland; Guanacaste; Tempisque river; Costa Rica
• Online Access: https://www.mdpi.com/2073-4441/11/4/674

The hydrology of tropical seasonal wetlands is affected by changes in the land cover. Changes from open water towards a vegetated cover imply an increase in the total evaporation flux, which includes the evaporation from open water bodies and the transpiration from vegetated surfaces. This study quantified the total evaporation flux of six covers of the Palo Verde wetland during dry season. The selected wetland covers were dominated by <i>Neptunia natans</i> (L.f.) Druce, <i>Thalia geniculata</i> L., <i>Typha dominguensis</i> Pers., <i>Eichhornia crassipes</i> (Mart.) Solms, a mixture of these species, and open water conditions. The plants were collected from the wetland and placed in lysimeters (59.1 L) built from plastic containers. The lysimeters were located in an open area near the meteorological station of the Organization for Tropical Studies (OTS). The evaporated water volume and meteorological data were collected between December 2012&#8211;January 2013. A completely randomized design was applied to determine the total evaporation (<i>E</i>), reference evaporation (<inline-formula> <math display="inline"> <semantics> <msub> <mi>E</mi> <mi>ref</mi> </msub> </semantics> </math> </inline-formula>, Penman-Monteith method) and crop coefficient (<inline-formula> <math display="inline"> <semantics> <msub> <mi>K</mi> <mi mathvariant="normal">c</mi> </msub> </semantics> </math> </inline-formula>) for all the covers. <i>T. geniculata</i> (<i>E</i>: 17.0 mm d<inline-formula> <math display="inline"> <semantics> <msup> <mrow></mrow> <mrow> <mo>&#8722;</mo> <mn>1</mn> </mrow> </msup> </semantics> </math> </inline-formula>, <inline-formula> <math display="inline"> <semantics> <msub> <mi>K</mi> <mi mathvariant="normal">c</mi> </msub> </semantics> </math> </inline-formula>: 3.43) and open water (<i>E</i>: 8.2 mm d<inline-formula> <math display="inline"> <semantics> <msup> <mrow></mrow> <mrow> <mo>&#8722;</mo> <mn>1</mn> </mrow> </msup> </semantics> </math> </inline-formula>, <inline-formula> <math display="inline"> <semantics> <msub> <mi>K</mi> <mi mathvariant="normal">c</mi> </msub> </semantics> </math> </inline-formula>: 1.65) showed the highest and lowest values respectively, for daily evaporation and crop coefficient. Results from the ANOVA indicate that <i>E. crassipes</i> and <i>N. natans</i> were statistically different (<i>p</i> = 0.05) from <i>T. dominguensis</i> and the species mixture, while the water and <i>T. geniculata</i> showed significant differences with regard to other plant covers. These results indicate that the presence of emergent macrophytes as <i>T. geniculata</i> and <i>T. dominguensis</i> will increase the evaporation flux during dry season more than the floating macrophytes or open water surfaces.