Mangrove and Mangrove-Fringe Wetlands in Ostional, Nicaragua: Current Conditions and Pathways Forward

Mangrove forests have traditionally protected the coastline of Ostional, a rural Nicaraguan fishing village, from degradation of fishery habitat and onshore effects of storm surge. Swaths of mangrove were converted to agricultural use before the ecological role of these mangroves was understood. We assessed the soils, hydrology, and vegetation of the intact mangrove and adjacent converted mangrove to inform a nonprofit conservation agency (Paso Pacifico) regarding the potential for ecosystem function restoration in this landscape

Mangrove and Mangrove-Fringe Wetlands in Ostional, Nicaragua: Current Conditions and Pathways Forward

Mangrove forests have traditionally protected the coastline of Ostional, a rural Nicaraguan fishing village, from degradation of fishery habitat and onshore effects of storm surge. Swaths of mangrove were converted to agricultural use before the ecological role of these mangroves was understood. We assessed the soils, hydrology, and vegetation of the intact mangrove and adjacent converted mangrove to inform a nonprofit conservation agency (Paso Pacifico) regarding the potential for ecosystem function restoration in this landscape

Ericoid Mycorrhizas in Organic Substrates: Distribution of Ericoid Mycorrhizas among Epiphytes in a Costa Rican Cloud Forest and Uptake of Organic Nitrogen by Ericoid, Ecto-, and Arbuscular Mycorrhizal Pygmy Forest Plants

The success of Ericaceae in organic substrates worldwide is frequently attributed to the exceptional ability of ericoid mycorrhizal (ERM) fungi to acquire organic N. However, much of the supporting research has been conducted in axenic laboratory conditions on boreal and arctic species. I investigated the occurrence and morphology of ericoid mycorrhizas in a neotropical forest and assessed the ability of temperate ERM species rooted in soils to acquire intact organic N (glycine-2 13C, 15N) and to acquire N from 15N-enriched litter. Co-occurring arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) species were included for comparison. Terrestrial and epiphytic ericaceous species collected in a neotropical cloud forest (Costa Rica) hosted typical ERM structures, dark septate endophytes (DSE), and, unexpectedly, fungal mantles and pseudo-Hartig nets. This diversity supports the emerging hypothesis that multiple fungal species may occupy ericaceous roots concurrently. Non-ericaceous roots (Araceae, Clusiaceae, Piperaceae) were AM, DSE, or non-mycorrhizal

Ericoid Mycorrhizas in Organic Substrates: Distribution of Ericoid Mycorrhizas among Epiphytes in a Costa Rican Cloud Forest and Uptake of Organic Nitrogen by Ericoid, Ecto-, and Arbuscular Mycorrhizal Pygmy Forest Plants

The success of Ericaceae in organic substrates worldwide is frequently attributed to the exceptional ability of ericoid mycorrhizal (ERM) fungi to acquire organic N. However, much of the supporting research has been conducted in axenic laboratory conditions on boreal and arctic species. I investigated the occurrence and morphology of ericoid mycorrhizas in a neotropical forest and assessed the ability of temperate ERM species rooted in soils to acquire intact organic N (glycine-2 13C, 15N) and to acquire N from 15N-enriched litter. Co-occurring arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) species were included for comparison. Terrestrial and epiphytic ericaceous species collected in a neotropical cloud forest (Costa Rica) hosted typical ERM structures, dark septate endophytes (DSE), and, unexpectedly, fungal mantles and pseudo-Hartig nets. This diversity supports the emerging hypothesis that multiple fungal species may occupy ericaceous roots concurrently. Non-ericaceous roots (Araceae, Clusiaceae, Piperaceae) were AM, DSE, or non-mycorrhizal

Connecting the Dots: Hydrologic Connectivity Between Wetlands and Other Wetlands and Waterbodies

Wetlands perform numerous ecosystem functions that in turn provide abundant ecosystem services beneficial to humankind. These may include, but are not limited to, flood water storage and release, nutrient transformations, carbon sequestration, and the provision of habitat or refugia. The importance of wetland effects on downgradient waters, such as other wetlands or streams, lies in the degree to which they are hydrologically connected or disconnected across the landscape

Connecting the Dots: Hydrologic Connectivity Between Wetlands and Other Wetlands and Waterbodies

Wetlands perform numerous ecosystem functions that in turn provide abundant ecosystem services beneficial to humankind. These may include, but are not limited to, flood water storage and release, nutrient transformations, carbon sequestration, and the provision of habitat or refugia. The importance of wetland effects on downgradient waters, such as other wetlands or streams, lies in the degree to which they are hydrologically connected or disconnected across the landscape

Rapid Uptake of \u3csup\u3e15\u3c/sup\u3eN-ammonium and glycine-\u3csup\u3e13\u3c/sup\u3eC, \u3csup\u3e15\u3c/sup\u3eN by Arbuscular and Ericoid Mycorrhizal Plants Native to a Northern California Coastal Pygmy Forest

While it is well established that plants are able to acquire nitrogen in inorganic form, there is less information on their ability to ‘short circuit’ the N cycle, compete with microbes, and acquire nitrogen in organic form. Mycorrhizal fungi, known to enhance nutrient uptake by plants, may play a role in organic N uptake, particularly ericoid mycorrhizas. We asked the question—Can mycorrhizal fungi increase the ability of plants to take up organic N, compared to inorganic N? Here, we report on the abilities of three plant species, ericoid mycorrhizal Rhododendron macrophyllum and Vaccinium ovatum and arbuscular mycorrhizal Cupressus goveniana ssp. pigmaea, to acquire C and/or N from an organic and an inorganic N source. All three species are native to a California coastal pygmy forest growing in acidic, low-fertility, highly organic soils. In a pot study, glycine-α13C, 15N and 15N-ammonium were applied to pygmy forest soil for 17 or 44 h. Ericoid mycorrhizal species did not demonstrate a preference for either inorganic or organic sources of N while Cupressusacquired more NH4-N than glycine-N. For all species, glycine-N uptake did not increase after 17 h suggesting glycine uptake and glycine immobilization occurred rapidly. Both glycine-N and glycine-C were recovered in shoots and in roots suggesting that all species acquired some N in organic form. Regression analyses of glycine-N and glycine-C recovery in root tissue indicate that much of the glycine was taken up intact and that the minimum proportion of glycine-N recovered in organic form was 85% (Cupressus) and 70% (Rhododendron). Regressions were non-significant for Vaccinium. For all species, glycine-N remained predominantly in roots while glycine-C was transferred to shoots. In contrast, NH4-N remained in roots of ericoid plants but was transferred to shoots of arbuscular mycorrhizal Cupressus. Since net N mineralization rates in pygmy forest soils are low, our results suggest that organic N may be an important N source for plants in this temperate coniferous ecosystem regardless of mycorrhizal type. Acquisition of amino acid C by these species also may partially offset the carbon cost to plants of hosting mycorrhizal fungi