Ecosystem Development After Mangrove Wetland Creation: Plant–Soil Change Across a 20-Year Chronosequence

Mangrove wetland restoration and creation efforts are increasingly proposed as mechanisms to compensate for mangrove wetland losses. However, ecosystem development and functional equivalence in restored and created mangrove wetlands are poorly understood. We compared a 20-year chronosequence of created tidal wetland sites in Tampa Bay, Florida (USA) to natural reference mangrove wetlands. Across the chronosequence, our sites represent the succession from salt marsh to mangrove forest communities. Our results identify important soil and plant structural differences between the created and natural reference wetland sites; however, they also depict a positive developmental trajectory for the created wetland sites that reflects tightly coupled plant-soil development. Because upland soils and/or dredge spoils were used to create the new mangrove habitats, the soils at younger created sites and at lower depths (10–30?cm) had higher bulk densities, higher sand content, lower soil organic matter (SOM), lower total carbon (TC), and lower total nitrogen (TN) than did natural reference wetland soils. However, in the upper soil layer (0–10?cm), SOM, TC, and TN increased with created wetland site age simultaneously with mangrove forest growth. The rate of created wetland soil C accumulation was comparable to literature values for natural mangrove wetlands. Notably, the time to equivalence for the upper soil layer of created mangrove wetlands appears to be faster than for many other wetland ecosystem types. Collectively, our findings characterize the rate and trajectory of above- and below-ground changes associated with ecosystem development in created mangrove wetlands; this is valuable information for environmental managers planning to sustain existing mangrove wetlands or mitigate for mangrove wetland losses.     

A comparison of species composition and stand structure between planted and natural mangrove forests in Shenzhen Bay,South China

Aims For assisting faster restoration of damaged or severely disturbed coastal ecosystems, selected mangrove species have been planted on previously mangrove-inhabited sites of the tropical and subtropical coasts of southern China. The objective of this study was to understand the stand dynamics of the planted mangroves and their functional traits in comparison with natural mangrove forests under similar site conditions.Methods Species composition, stand density, tree size distribution, and aboveground production were investigated along three transects in a 50-year-old planted mangrove stand and three transects in an adjacent natural mangrove stand in Shenzhen Bay, South China. Measurements were made on tree distribution by species, stand structure, and aboveground biomass (AGB) distribution. Analyses were performed on the spatial patterns of tree size distribution and species association.Important findings We found that the planted and natural mangrove stands did not differ in stand density, average diameter at breast height (DBH), species composition, and AGB. Spatial distribution of AGB and frequency at species level were also similar between the planted and natural stands. However, the traits in stand structure were more variable in the planted stand than in the natural stand, indicating higher spatiotemporal heterogeneity in the development and succession of planted mangroves. Geostatistical analyses show that both DBH and AGB were spatially auto-correlated within a specific range in the direction perpendicular to coastline. More than 60% of the variance in these attributes was due to spatial autocorrelation. The Ripley's K -function analysis shows that the two dominant species, Kandelia obovata and Avicennia marina, clumped in broader scales in the natural stand than in the planted stand and displayed significant interspecific competition across the whole transect. It is suggested that interspecific competition interacts with spatial autocorrelation as the underlying mechanism shaping the mangrove structure. This study demonstrates that at age 50, mangrove plantations can perform similarly in stand structure, spatial arrangement of selected stand characteristics and species associations to the natural mangrove forests.     

Predicting and quantifying the structure of tropical dry forests in South Florida and the Neotropics using spaceborne imagery

Aim This research examines environmental theories and remote sensing methods that have been hypothesized to be associated with tropical dry forest structure. Location Tropical dry forests of South Florida and the Neotropics. Methods Field measurements of stand density, basal area and tree height were collected from 22 stands in South Florida and 30 stands in the Neotropics. In South Florida, field measurements were compared to climatic (temperature, precipitation, hurricane disturbance) and edaphic (rockiness, soil depth) variables, spectral indices (NDVI, IRI, MIRI) from Landsat 7 ETM+, and estimates of tree height from the Shuttle Radar Topography Mission (SRTM) and the National Elevation Dataset (NED). Environmental variables associated with tropical dry forest structure in South Florida were compared to tropical dry forest in other Neotropical sites. Results There were significant correlations among temperature and precipitation, and stand density and tree height in South Florida. There were significant correlations between (i) stand density and mean NDVI and standard deviation of NDVI, (ii) MIRI and stand density, basal area and mean tree height, and (iii) estimates of tree height from SRTM with maximum tree height. In the Neotropics, there were no relationships between temperature or precipitation and tropical dry forest structure, however, Neotropical sites that experience hurricane disturbance had significantly shorter tree heights and higher stand densities. Main conclusions It is possible to predict and quantify the forest structure characteristics of tropical dry forests using climatic data, Landsat 7 ETM+ imagery and SRTM data in South Florida. However, results based on climatic data are region‐specific and not necessarily transferable between tropical dry forests at a continental spatial scale. Spectral indices from Landsat 7 ETM+ can be used to quantify forest structure characteristics, but SRTM data are currently not transferable to other regions. Hurricane disturbance has a significant impact on forest structure in the Neotropics.     

Facilitating the restoration of aquatic plant communities in a Ramsar wetland

Human activities such as land clearing and intensive land use around water bodies, particularly wetlands, have a detrimental impact on water quality and quantity, aquatic plant communities, and associated wetland fauna. Lake Alexandrina and Lake Albert are internationally significant Ramsar wetlands located at the terminus of the Murray River, Australia's longest river system. Agriculture, water regulation, and extraction and droughts have had a detrimental impact on native plant communities in the lakes. We studied the influence of young (<1–3 years) and old (8–11 years) plantings of a native sedge (bulrush), Schoenoplectus tabernaemontani, to facilitate the establishment of aquatic plant communities in comparison with remnant and control sites. We also measured how planting structure (height, stand width, and stem density) changed with age in comparison with remnant sites. Results suggest that as plantings age they get substantially wider and have a greater maximum height, although do not reach similar stand widths by 11 years when compared to remnant areas. However, old plantings do not differ from remnant habitats in relation to aquatic plant species richness, counts of aquatic plants, and community composition. Young plantings have substantially less abundant and diverse plant communities, but are developing on a similar trajectory to old plantings. It is likely that planting sedges along lake shorelines causes a breakwater effect that facilitates the recolonization of wetland plants between the planted area and the water's edge. Management agencies should consider restoring native sedges to increase aquatic biodiversity, and potentially reduce erosion.     

Spatial variations in macrobenthic fauna recolonisation in a tropical mangrove bay

Recolonisation by crab species and sediment-infauna taxa (at class level) in artificially regenerated mangrove stands of Avicennia marina, Rhizophora mucronata and Sonneratia alba (5 yr old) were studied using respective bare sites (open without mangroves or denuded) and natural sites (relatively undisturbed) as controls. The controls were chosen based on site history, physical proximity and tidal inundation class in reference to the particular reforested mangrove stand and samples randomly taken. A number of environmental variables were measured; interstitial water salinity and temperature (measured at low tide) were lower, whereas sediment organic matter content was higher in the areas with mangrove cover, with the natural sites having the highest content. The bare sites were generally sandier, whereas the areas with mangrove cover had higher proportions of clay and silt. Generally, there was a higher crab density in the reforested sites than in the bare sites, whereas crab species diversity (Shannon diversity index) did not vary from one site to another for any of the mangrove species. In terms of crab species composition, the reforested sites were more similar (Sørensen similarity coefficient) to the natural sites and less to the bare controls. For sediment-infauna, the reforested sites had a significantly higher density than the respective bare controls, while the natural sites had the highest density. The number of sediment-infauna taxa in both the reforested and natural sites of all the mangrove species was similar and higher than in the comparable bare sites. The results suggest that the reforested sites are supporting more faunal recolonisation, and therefore becoming more akin to the natural mangrove sites in terms of the investigated functional indicators. The findings seem to support the use of artificial mangrove regeneration (in areas where natural regeneration has been impeded by physical conditions or otherwise) as an effective management tool in the restoration and conservation of the functional integrity of degraded mangrove habitats.Key words: Crabs, Environmental variables, Kenya, Recolonisation, Restored mangroves, Sediment-infauna     

Woody Debris in the Mangrove Forests of South Florida1

Woody debris is abundant in hurricane‐impacted forests. With a major hurricane affecting South Florida mangroves approximately every 20 yr, carbon storage and nutrient retention may be influenced greatly by woody debris dynamics. In addition, woody debris can influence seedling regeneration in mangrove swamps by trapping propagules and enhancing seedling growth potential. Here, we report on line‐intercept woody debris surveys conducted in mangrove wetlands of South Florida 9–10 yr after the passage of Hurricane Andrew. The total volume of woody debris for all sites combined was estimated at 67 m³/ha and varied from 13 to 181 m³/ha depending upon differences in forest height, proximity to the storm, and maximum estimated wind velocities. Large volumes of woody debris were found in the eyewall region of the hurricane, with a volume of 132 m³/ha and a projected woody debris biomass of approximately 36 t/ha. Approximately half of the woody debris biomass averaged across all sites was associated as small twigs and branches (fine woody debris), since coarse woody debris >7.5 cm felled during Hurricane Andrew was fairly well decomposed. Much of the small debris is likely to be associated with post‐hurricane forest dynamics. Hurricanes are responsible for large amounts of damage to mangrove ecosystems, and components of associated downed wood may provide a relative index of disturbance for mangrove forests. Here, we suggest that a fine:coarse woody debris ratio ≤0.5 is suggestive of a recent disturbance in mangrove wetlands, although additional research is needed to corroborate such findings.     

Vegetation and soil characteristics as indicators of restoration trajectories in restored mangroves

We investigated the restoration trajectories in vegetation and soil parameters of monospecific Rhizophora mucronata stands planted 6, 8, 10, 11, 12, 17, 18, and 50 years ago (restored system). We tested the hypothesis that the changes in vegetation characteristics, with progressing mangrove age, are related to the changes in soil characteristics. The vegetation and soil parameters were compared across this restoration sequence using a reference system comprising mature, natural mangrove stands of unknown age. Rapid increases in leaf area index and aboveground biomass, and declines in tree density and size (in terms of tree diameter and height) occurred with increasing stand age. Soil organic matter, total nitrogen, and soil redox potential increased, and soil temperature decreased as stands aged. These patterns tended to stabilize at approximately the 11th year, indicating the probable age that restoration plots tend toward forest maturity. The time for the restored systems to reach forest maturity, attaining characteristics similar to the reference system, is estimated at 25 years, which is relatively slow compared to forest regeneration trajectories estimated for natural mangroves. Our study describes the trajectory patterns for planted mangroves, which are important for the assessment of both the progress and success of mangrove rehabilitation programs.     

红树林湿地恢复研究进展

红树林是生长在热带、亚热带隐蔽潮间带的独特植物群落,在过去几十年内因人口压力和经济发展而遭到严重破坏,质量下降,面积萎缩.近年来,尽管世界各地采取了一系列措施进行红树林的恢复,然而由于缺乏造林技术资料、造林成活率低下、经营管理粗放,加上人为干扰和自然灾害的影响,红树林面积增长缓慢;造林成活率低依然是制约红树林湿地恢复的主要因素.总结了近年来国内外红树林湿地恢复四个方面的研究成果,即(1)宜林地选择,包括温度、底质、水文的环境条件研究;(2)树种选择与引种,包括乡土树种的选用和外来树种的引种状况;(3)栽培技术的应用,包括造林栽培技术与育苗技术,造林成本的比较;(4)植后管护及监测,包括幼林巡护、病虫害防治、生态监测,结合野外调查的结果,综述了红树林恢复的一些基本原理与应用实例.根据我国红树林湿地恢复的现状,提出今后红树林恢复研究的重点为:开展"退塘还林"工程,监测红树林湿地生态系统生物多样性的恢复,深入探讨红树林的化感作用,营造红树林混交林,实现红树林的生态恢复.     

Litter decomposition in created and reference wetlands in West Virginia,USA

Large amounts of resources have gone into wetland mitigation in recent years; however, it is still unclear whether wetland function is being replaced along with wetland area. Litter decomposition is linked to numerous wetland functions. In this study, we measured plant litter decomposition potential over 12 months in 8 created and 8 reference wetlands located in the Allegheny Mountains of West Virginia, USA. Broadleaf cattail (Typha latifolia L.) litter bags were placed in each wetland and collected at 3 month intervals. Linear decomposition rate constants and percent mass remaining were similar between wetland types (created and reference) and among Cowardin classifications (palustrine: unconsolidated bottom, aquatic bed, emergent, and scrub/shrub). Created wetland age was not correlated with decomposition potential. Our study found that created wetlands had similar litter decomposition potential as reference wetlands indicating that similar processes are likely acting upon litter decomposition within both natural and created wetlands.     

Restored oyster reefs and living shorelines can augment predator trophic dynamics

Coastal habitat loss has led to declines in many higher trophic level predators. These declines can be mitigated through habitat restoration, which putatively enhances predator populations and trophic dynamics by creating foraging opportunities in reestablished habitat, but this lacks empirical support. Here, we assess the prediction restored coastal habitat supports sportfish feeding relationships similar to natural habitat, at restored oyster reefs (Crassostrea virginica) and living shoreline habitats in Florida, U.S.A. Stable isotopes and gut contents were analyzed from young sportfish (i.e. predatory fish targeted by anglers) collected at control and restored sites for up to 3 years. The influence of habitat features, predator size, and prey availability on carbon and nitrogen isotope values were examined using a model species (mangrove/gray snapper [Lutjanus griseus]). In summary, sportfish species had distinct isotopic values, consuming similar prey but in different proportions between habitats. Prey abundance and richness, and reef height were influential predictors of L. griseus stable isotope values, with restored reefs contributing to their diet more than controls according to Bayesian mixing models. The trophic niche area of L. griseus and their predominant prey achieved trophic equivalence between restored and natural oyster reefs within 1 year following restoration. Stabilized living shorelines attained trophic equivalency to natural shorelines, but may take longer to accrue prey for some species. These findings generate fundamental ecological knowledge and actionable science, including targets, timelines, and indicator species, that natural resource managers and restoration practitioners can use to assess trophic structure and success of coastal habitat restoration.     

Long-Term Growth and Succession in Restored and Natural Mangrove Forests in Southwestern Florida

We compared colonization, growth and succession from 1989 to 2000 in a restored mangrove site and in gap and closed canopy sites in a natural mangrove forest. The restored site was created in 1982 and planted with Rhizophora mangle (≈2 m⁻²) propagules. By 1989, Laguncularia racemosa, with densities up to 12.9 tree m⁻², was a dominant in all plots, although densities were greater at edge plots relative to inner plots, and near open water (west plots) relative to further inland (east plots), and in tall mangrove plots relative to scrub plots. Rhizophora mangle (1989 tree densities about 2 m⁻²) was a codominant in inner and scrub plots, while Avicennia germinans had the lowest densities (<1 tree m⁻²) in all plots. From 1989 to 2000 L. racemosa experienced reduced recruitment and apparent density-dependent mortality of canopy individuals in plots with high initial densities. Scrub plots experienced high rates of colonization by R. mangle and L. racemosa, rapid growth in height of all species (1989–1996), followed by a dieoff of L. racemosa in later years (1997–2000) as the canopy came to resemble that of tall mangrove plots. Colonization and growth rates were lower in gap and closed canopy regions of the natural forest relative to rates in the restored site. After 11 years, densities of L. racemosa were 10–20× lower and R. mangle slightly less in the gap relative to densities in tall mangrove plots in the restored site at the same age. Although the restored stand had converged with the natural forest by 2000 in terms of some factors such as species richness, vegetation cover, litterfall, and light penetration, trees were still much smaller and stem densities much higher. Full development of mature structure and ecological function will likely require decades more development.     

湛江市红树林资源及其可持续利用

广东省湛江市现有红树林面积7242.0hm²,人工造林未成林25.6hm²,天然更新红树林509.4hm²,另有红树林宜林地9688.6hm²。红树林及其伴生植物主要有木榄(Bruguiera gymnorrhiza)、秋茄(Kandelia candel)、无瓣海桑(Sonneratia apetala)等15科24种。由于毁林养虾、养鱼等导致1980～2001年占用红树林地面积6363.6hm²。从总体上看,湛江红树林种类多,群落类型丰富;红树林面积大幅减少,影响区域社会经济发展;除乡土种外,无瓣海桑是一种较成功的外来引树种;宜林地多,但人工造林保存率不高;破坏红树林,挖塘养殖依然较普遍。为了实现湛江红树林的可持续发展,需要加强下列工作:建立自然保护区加强对现有红树林湿地的保护;开展红树林湿地生态系统资源监测和鸟类环志;科学规划后加快红树林的恢复和重建;积极推动退塘还林并合理利用红树林;依法保护管理好红树林;多途径筹集保护资金;加强红树林、湿地的保护和宣传。     

Hydrologic restoration in a dynamic subtropical mangrove‐to‐marsh ecotone

Extensive hydrologic modifications in coastal regions across the world have occurred to support infrastructure development, altering the function of many coastal wetlands. Wetland restoration success is dependent on the existence of hydrologic regimes that support development of appropriate soils and the growth and persistence of wetland vegetation. In Florida, United States, the Comprehensive Everglades Restoration Program (CERP) seeks to restore, protect, and preserve water resources of the greater Everglades region. Herein we describe vegetation dynamics in a mangrove‐to‐marsh ecotone within the impact area of a CERP hydrologic restoration project currently under development. Vegetation communities are also described for a similar area outside the project area. We found that vegetation shifts within the impact area occurred over a 7‐year period; cover of herbaceous species varied by location, and an 88% increase in the total number of mangrove seedlings was documented. We attribute these shifts to the existing modified hydrologic regime, which is characterized by a low volume of freshwater sheet flow compared with historical conditions (i.e. before modification), as well as increased tidal influence. We also identified a significant trend of decreasing soil surface elevation at the impact area. The CERP restoration project is designed to increase freshwater sheet flow to the impact area. Information from our study characterizing existing vegetation dynamics prior to implementation of the restoration project is required to allow documentation of long‐term project effects on plant community composition and structure within a framework of background variation, thereby allowing assessment of the project's success in restoring critical ecosystem functions.     

考洲洋人工种植红树林湿地大型底栖动物群落环境响应

2017年以来,广东省惠州市在考洲洋潮间带开展了大规模人工种植红树林生态修复工程,但考洲洋人工种植红树林湿地大型底栖动物群落的环境响应未见报道。根据2018-2019年四个季节在考洲洋盐洲大桥附近红树种植1-2年（X断面）和5-6年（Y断面）的两处湿地的大型底栖动物定量取样数据,分析了人工红树林湿地大型底栖动物的时空格局及其环境响应。方差分析表明,Y断面冬季的大型底栖动物群落的物种数、栖息密度、生物量、多样性指数（H''）和丰富度指数（d）,以及夏季的栖息密度均随潮高（海平面高程）降低而增加;而Y断面冬季的均匀度指数（J）、夏季的H''和J则是随潮高降低而减少。聚类（Cluster）和非度量多维尺度（nMDS）分析表明冬季和夏季X断面和Y断面大型底栖动物群落相似性较低,而春季和秋季X断面和Y断面大型底栖动物群落相似性较高。冬季和夏季最大潮高、潮差、大型底栖动物物种数、栖息密度、H''和d较春季和秋季的高。红树种植1-2年的X断面大型底栖动物物种数、H''和J低于种植5-6年的Y断面。上述结果证实潮汐和红树种植年限影响考洲洋红树林湿地大型底栖动物的群落结构,研究结果可为大型底栖动物多样性保护和生态修复提供基础资料。     

中国红树林生态系统主要害虫种类、 防控现状及成灾原因

红树林湿地是中国东南沿海的关键生态系统之一。近年来, 我国红树林陆续出现多种害虫种群暴发成灾的现象, 使红树林湿地的可持续利用面临严重挑战。本文归纳了近20年来中国红树林生态系统的主要害虫种类, 危害较严重的有海榄雌瘤斑螟Acrobasis sp., 毛颚小卷蛾Lasiognatha cellifera, 丽绿刺蛾Latoia lepida, 白囊袋蛾Chalioides kondonis, 蜡彩袋蛾Chalia larminati和小袋蛾Acanthopsyche subferalbata等; 对红树林虫害的防控现状进行总结, 目前开展的防控工作主要以生物农药、 昆虫生长调节剂、 昆虫天敌等生物防治方法为主, 结合灯光诱杀等物理防治手段的运用, 对暴发期的害虫种群可以取得较好的控制效果; 并从红树林生态系统健康水平和昆虫群落多样性等方面对害虫种群的成灾原因进行初步探讨; 最终提出以虫害可持续控制为目标的红树林生态系统生境调控策略, 以期为提高红树林湿地虫害管理水平以及促进红树林的可持续发展提供重要的理论参考和科学指导。     

Intertwined effects of climate and land use change on environmental dynamics and carbon accumulation in a mangrove‐fringed coastal lagoon in Java,Indonesia

The identification and quantification of natural carbon (C) sinks is critical to global climate change mitigation efforts. Tropical coastal wetlands are considered important in this context, yet knowledge of their dynamics and quantitative data are still scarce. In order to quantify the C accumulation rate and understand how it is influenced by land use and climate change, a palaeoecological study was conducted in the mangrove‐fringed Segara Anakan Lagoon (SAL) in Java, Indonesia. A sediment core was age‐dated and analyzed for its pollen and spore, elemental and biogeochemical compositions. The results indicate that environmental dynamics in the SAL and its C accumulation over the past 400 years were controlled mainly by climate oscillations and anthropogenic activities. The interaction of these two factors changed the lagoon's sediment supply and salinity, which consequently altered the organic matter composition and deposition in the lagoon. Four phases with varying climates were identified. While autochthonous mangrove C was a significant contributor to carbon accumulation in SAL sediments throughout all four phases, varying admixtures of terrestrial C from the hinterland also contributed, with natural mixed forest C predominating in the early phases and agriculture soil C predominating in the later phases. In this context, climate‐related precipitation changes are an overarching control, as surface water transport through rivers serves as the “delivery agent” for the outcomes of the anthropogenic impact in the catchment area into the lagoon. Amongst mangrove‐dominated ecosystems globally, the SAL is one of the most effective C sinks due to high mangrove carbon input in combination with a high allochthonous carbon input from anthropogenically enhanced sediment from the hinterland and increased preservation. Given the substantial C sequestration capacity of the SAL and other mangrove‐fringed coastal lagoons, conservation and restoration of these ecosystems is vitally important for climate change mitigation.     

Aquatic macroinvertebrate community responses to wetland mitigation in the Greater Yellowstone Ecosystem

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Coastal wetland restoration improves habitat for juvenile sportfish in Tampa Bay,Florida, U.S.A.

Increasing human populations and urban development have led to losses of estuarine habitats for fish and wildlife. Where resource managers are restoring coastal wetlands, in addition to meeting goals related to hydrologic connectivity, biodiversity, and recreational opportunities, efforts are being made to provide habitat that is suitable for juvenile sportfish. An 18‐month study was conducted to compare juvenile sportfish use of natural, restored, and impacted sites along Tampa Bay, Florida, shorelines. Juvenile sportfish densities at restored sites were broadly comparable to natural sites and greater than at impacted sites. However, site‐specific differences in sportfish use did occur within site types. For example, one restored site had significantly higher densities of red drum Sciaenops ocellatus than any other site, while black drum Pogonias cromis were found exclusively at another restored site. To evaluate whether the restored sites are providing suitable habitat for juvenile fish, we assessed growth (estimated from counts of daily rings on otoliths) and condition (determined by lipid analyses) of juvenile common snook Centropomus undecimalis, an archetypal coastal wetland‐dependent species. Growth (0.43–0.56 mm SL/day) and condition (4.6–6.1% lipid of dry weight) exhibited only site‐specific differences and did not vary among natural, restored, and impacted site types. Although mortality rates of juvenile sportfish were not determined, use of a 40‐m seine found that densities of potential piscine predators in these coastal wetlands were relatively low compared to published studies of open estuarine shorelines. The restoration and creation of coastal wetlands in Tampa Bay provides improved habitat for juvenile sportfish.     

Secondary succession impairment in restored mangroves

In this work it was hypothesized that secondary succession on sites that have been managed by single planting of mangrove species is compromised by residual stressors, which could reduce the ecosystem??s structural development and lower its functions. Forest structure and environmental characteristics of three planted mangrove stands are compared with reference sites. Structural attributes showed significant differences in the comparison of planted and reference stands. Avicennia schaueriana was the dominant species within both natural regeneration and old-growth stands in terms of basal area (99.2 and 99.4?%, 69.6 and 84.5?%, and 59.0 and 87.1?% for Itacorubi, Saco Grande, and Ratones, respectively). Restoration stands were dominated by Laguncularia racemosa (80.6 and 94.2?% for Saco Grande and Ratones, respectively), except at one site (Itacorubi), where A. schaueriana prevailed (99.7?%). Even though restoration and regeneration stands at Itacorubi showed similar species composition and dominance, cohort sorting revealed an inferior regeneration potential in the restoration stand. Multiple correlation analysis indicated that variables related to elevation disruptions (p _w ?=?0.521) were the environmental drivers responsible for the differences observed in forest structure. At restoration sites an impaired pattern of secondary succession was observed, indicating that single species plantings may be ineffective if characteristics of the site, as well as of the area surrounding it, are not considered. The inadequate management of restoration sites can therefore have implications for both immediate and long-term large-scale ecosystem services.     

Changes in vernal pool edaphic settings through mitigation at the project and landscape scale

Vernal pool mitigation is a highly controversial process that has been frequently criticized for its inability to adequately replicate the ecosystem functions of the original intact wetlands. We analyzed past mitigation practices in two rapidly growing counties in California's Great Central Valley to determine if mitigation procedures are re-arranging the vernal pool landscape by substituting more common or less ecologically significant pool types (as defined by soil type and geomorphology) for rarer or ecologically richer pool types. Results indicate that most development projects impacting vernal pools conduct at least a portion of their mitigation requirements at a site with similar edaphic settings. However, when examined at a landscape-scale across all development projects, the more common edaphic settings such as Northern Hardpan and Low Terrace pools are increasing while more rare types such as Northern Claypan and Volcanic Mudflow pools are decreasing. Results also show that Drainageway pools, a less-specialized pool type with generally lower species richness, are becoming more common through mitigation. These results are confirmed by an analysis of landscape diversity, which showed that overall landscape diversity was lower at mitigation sites than at project sites. Despite these results, the ecological significance of vernal pool mitigation practices remains unclear for several reasons. The lack of maps showing exact locations of vernal pools at project sites make it difficult to precisely determine vernal pool acreage and distribution among edaphic settings. Additionally, more research is needed to determine precise relationships between edaphic settings and species distributions and the effects of mitigation area management practices on species distribution and persistence.