USGS Science⌕ Search

SEARCH · USGS Science

Results for “Tropics”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,027 records · Page 57Linked to original sources
USGS2006

Bird communities of natural and modified habitats in Panama

Only a small proportion of land can realistically be protected as nature reserves and thus conservation efforts also must focus on the ecological value of agroecosystems and developed areas surrounding nature reserves. In this study, avian communities were surveyed in 11 habitat types in central Panama, across a gradient from extensive forest to intensive agricultural land uses, to examine patterns of species richness and abundance and community composition. Wooded habitats, including extensive and fragmented forests, shade coffee plantations, and residential areas supported the most species and individuals. Nearctic-Neotropical migratory species were most numerous in lowland forest fragments, shade coffee, and residential areas. Introduced Pinus caribbea and sugar cane plantations supported the fewest species compared to all other habitats. Cattle pastures left fallow for less than two years supported more than twice as many total species as actively grazed pastures, such that species richness in fallow pastures was similar to that found in wooded habitats. Community similarities were relatively low among all habitat types (none exceeding the observed 65% similarity between extensive and fragmented lowland forests), but communities in shade coffee and residential areas were 43% and 54′% similar to lowland forest fragments, respectively. Fallow pastures and residential areas shared 60% of their species. Bird communities in shade coffee and residential areas were characterized by higher proportions of frugivorous and nectarivorous species than in native forests. These same guilds also were better represented in fallow than in grazed pastures. Raptors and piscivorous species were most prevalent in cattle pastures and rice fields. These results, though based upon only species richness and abundance, demonstrate that many human-altered habitats have potential ecological value for birds, and conservation efforts in tropical areas should focus greater attention on enhancement of agricultural and developed lands as wildlife habitat. To understand the true conservation value of these modified lands will require examination not only of numbers but also of the types of species supported by these habitats, their reproductive output and survival rates.

Ecography↗
USGS2007

Evidence for exploitative competition: Comparative foraging behavior and roosting ecology of short-tailed fruit bats (Phyllostomidae)

Chestnut short-tailed bats, Carollia castanea, and Seba's short-tailed bats, C. perspicillata (Phyllostomidae), were radio-tracked (N = 1593 positions) in lowland rain forest at Tiputini Biodiversity Station, Orellana Province, Ecuador. For 11 C. castanea, mean home range was 6.8 ?? 2.2 ha, mean core-use area was 1.7 ?? 0.8 ha, and mean long axis across home range was 438 ?? 106 m. For three C. perspicillata, mean home range was 5.5 ?? 1.7 ha, mean core-use area was 1.3 ?? 0.6 ha, and mean long axis was 493 ?? 172 m. Groups of less than five C. castanea occupied day-roosts in earthen cavities that undercut banks the Tiputini River. Carollia perspicillata used tree hollows and buildings as day-roosts. Interspecific and intraspecific overlap among short-tailed bats occurred in core-use areas associated with clumps of fruiting Piper hispidum (peppers) and Cecropia sciadophylla. Piper hispidum seeds were present in 80 percent of the fecal samples from C. castanea and 56 percent of samples from C. perspicillata. Carollia perspicillata handled pepper fruits significantly faster than C. castanea; however, C. castanea commenced foraging before C. perspicillata emerged from day-roosts. Evidence for exploitative competition between C. castanea and C. perspicillata is suggested by our observations that 95 percent of ripe P. hispidum fruits available at sunset disappear before sunrise (N = 74 marked fruits). Piper hispidum plants produced zero to 12 ripe infructescences per plant each night during peak production. Few ripe infructescences of P. hispidum were available during the dry season; however, ripe infructescences of C. sciadophylla, remained abundant. ?? 2007 The Author(s) Journal compilation ?? 2007 by The Association for Tropical Biology and Conservation.

Biotropica↗
USGS2007

Effects of season, rainfall, and hydrogeomorphic setting on mangrove tree growth in Micronesia

Seasonal patterns of tree growth are often related to rainfall, temperature, and relative moisture regimes. We asked whether diameter growth of mangrove trees in Micronesia, where seasonal changes are minimal, is continuous throughout a year or conforms to an annual cycle. We installed dendrometer bands on Sonneratia alba and Bruguiera gymnorrhiza trees growing naturally within mangrove swamps on the islands of Kosrae, Federated States of Micronesia (FSM), Pohnpei, FSM, and Butaritari, Republic of Kiribati, in the eastern Caroline Islands of the western Pacific Ocean. Trees were remeasured monthly or quarterly for as long as 6 yr. Annual mean individual tree basal area increments ranged from 7.0 to 79.6 cm2/yr for all S. alba trees and from 4.8 to 27.4 cm2/yr for all B. gymnorrhiza trees from Micronesian high islands. Diameter increment for S. alba on Butaritari Atoll was lower at 7.8 cm 2/yr for the one year measured. Growth rates differed significantly by hydrogeomorphic zone. Riverine and interior zones maintained up to seven times the annual diameter growth rate of fringe forests, though not on Pohnpei, where basal area increments for both S. alba and B. gymnorrhiza were approximately 1.5 times greater in the fringe zone than in the interior zone. Time-series modeling indicated that there were no consistent and statistically significant annual diameter growth patterns. Although rainfall has some seasonality in some years on Kosrae and Pohnpei and overall growth of mangroves was sometimes related positively to quarterly rainfall depths, seasonal diameter growth patterns were not distinctive. A reduced chance of moisture-related stress in high-rainfall, wetland environments may serve to buffer growth of Micronesian mangroves from climatic extremes. ?? 2007 The Author(s) Journal compilation ?? 2007 by The Association for Tropical Biology and Conservation.

Biotropica↗
USGS2006

Dependence of soil respiration on soil temperature and soil moisture in successional forests in Southern China

The spatial and temporal variations in soil respiration and its relationship with biophysical factors in forests near the Tropic of Cancer remain highly uncertain. To contribute towards an improvement of actual estimates, soil respiration rates, soil temperature, and soil moisture were measured in three successional subtropical forests at the Dinghushan Nature Reserve (DNR) in southern China from March 2003 to February 2005. The overall objective of the present study was to analyze the temporal variations of soil respiration and its biophysical dependence in these forests. The relationships between biophysical factors and soil respiration rates were compared in successional forests to test the hypothesis that these forests responded similarly to biophysical factors. The seasonality of soil respiration coincided with the seasonal climate pattern, with high respiration rates in the hot humid season (April-September) and with low rates in the cool dry season (October-March). Soil respiration measured at these forests showed a clear increasing trend with the progressive succession. Annual mean (± SD ) soil respiration rate in the DNR forests was (9.0 ± 4.6) Mg CO 2 -C/hm 2 per year, ranging from (6.1 ± 3.2) Mg CO 2 -C/hm 2 per year in early successional forests to (10.7 ± 4.9) Mg CO 2 -C/hm 2 per year in advanced successional forests. Soil respiration was correlated with both soil temperature and moisture. The T/M model, where the two biophysical variables are driving factors, accounted for 74%-82% of soil respiration variation in DNR forests. Temperature sensitivity decreased along progressive succession stages, suggesting that advanced-successional forests have a good ability to adjust to temperature. In contrast, moisture increased with progressive succession processes. This increase is caused, in part, by abundant respirators in advanced-successional forest, where more soil moisture is needed to maintain their activities.

Journal of Integrative Plant Biology↗
USGS2006

Status of dugongs in waters around Palau

The dugong, Dugong dugon , is widely distributed throughout the Indo-Pacific region in shallow tropical and subtropical waters (Nishiwaki and Marsh 1985).The International Union for Conservation of Nature and Natural Resources lists the species as vulnerable (Thornback and Jenkins 1982), as it is severely depleted or extinct in many parts of its former range (Nishiwaki and Marsh 1985). Many populations at isolated archipelagos have been exterminated through direct human exploitation. Husar (1975) cited evidence of the former existence of dugongs around the Mascarene, Laccadive, Maldive, Barren, Narcondom, Cocos (Keeling), Christmas, and Lesser Sunda islands. An isolated dugong population still occurs around Palau (Republic of Belau), Western Caroline Islands, about 850 km from both Papua New Guinea to the south and the Philippines to the west. The first aerial surveys of this population, in 1977 and 1978, indicated that it was small and other evidence suggested it was subject to persistent poaching (Brownell et al. 1981). We resurveyed this population in 1983 to reassess its status and attempt to detect any changes in distribution or abundance. With the assistance of the Palau Department of Natural Resources, we also interviewed fishermen and knowledgeable residents about dugong abundance, distribution, mortality, and natural history. Surveys were conducted from 19 through 26 August, using a Cessna 206high-wing airplane flown at an altitude of 150 to 300 m and an airspeed of about 170 km/h. An observer sat in each rear seat, and a third observer, who also navigated and recorded the data directly onto maps, sat in the right front seat. Small animals close to another dugong were considered calves. The survey route, based on that of Brownell et al. (19Sl), covered much of the approximately 1,380 sq km of dugong habitat within the archipelago. The islands are surrounded by very deep water, which restricts dugong habitat to lagoon areas within about 3 km of shore. Surveys were flown about 0.5 km offshore and the same distance inside the fringing reefs, with transects about 1 km apart across the larger lagoons. The coast was divided into the same 12 segments used by Brownell et al. (1981) (Fig. 1). However, the area outside the western fringing reef was not surveyed because no dugongs were sighted there in either1977 or 1978. We surveyed the entire archipelago twice and carried out replicated surveys of the lagoon areas and Malakal Harbor, which had been used by relatively large numbers of dugongs in 1977 and 1978 (Table 1). The total survey time was 15 h.265Help Volumes Main Menu

Marine Mammal Science↗
USGS2011

Climate change, atmospheric rivers, and floods in California - a multimodel analysis of storm frequency and magnitude changes

Recent studies have documented the important role that “atmospheric rivers” (ARs) of concentrated near‐surface water vapor above the Pacific Ocean play in the storms and floods in California, Oregon, and Washington. By delivering large masses of warm, moist air (sometimes directly from the Tropics), ARs establish conditions for the kinds of high snowlines and copious orographic rainfall that have caused the largest historical storms. In many California rivers, essentially all major historical floods have been associated with AR storms. As an example of the kinds of storm changes that may influence future flood frequencies, the occurrence of such storms in historical observations and in a 7‐model ensemble of historical‐climate and projected future climate simulations is evaluated. Under an A2 greenhouse‐gas emissions scenario (with emissions accelerating throughout the 21st Century), average AR statistics do not change much in most climate models; however, extremes change notably. Years with many AR episodes increase, ARs with higher‐than‐historical water‐vapor transport rates increase, and AR storm‐temperatures increase. Furthermore, the peak season within which most ARs occur is commonly projected to lengthen, extending the flood‐hazard season. All of these tendencies could increase opportunities for both more frequent and more severe floods in California under projected climate changes.

California↗
USGS2015

The first description of oarfish Regalecus glesne ( Regalecus russellii Cuvier 1816) ageing structures

Despite being a large, conspicuous teleost with a worldwide tropical and temperate distribution, the giant oarfish Regalecus spp. remain very rare fish species in terms of scientific sampling. Subsequently, very little biological information is known about Regalecus spp. and almost nothing has been concluded in the field of age and growth (Roberts, 2012). No studies of otoliths or temporal (annual) markings on any hard structures have been reported, and to our knowledge otoliths have never been recovered from any specimens (Tyson Roberts, personal communication),although a few texts do provide illustrations of Regalecus sp. otoliths (Lin and Chang, 2012; Nolf, 2013). Further inferential difficulty comes from the fact that age and growth studies of any Lampridiforme species are rare. Lampris guttatus is perhaps the only Lampridiforme species for which any biological information has been reported(Francis et al., 2004), which stems from the species commercial value. In order to begin understanding any species (for later purposes of management, conservation, etc.), basic biological information is needed. In the present study, we examine not only the first Regalecus russellii otolith, but provide suggestions toward future work that should direct data collection that can be used to generate basic biological information for this species.

Journal of Applied Ichthyology↗
USGS2022

Activity patterns of Hawaiian forest birds in a fragmented and continuous landscape

Activity patterns are a key component of avian life history and behavior, and decisions about how activity periods are structured can have important fitness implications. Despite the importance of activity patterns, individual variability in activity is poorly studied in small birds. We used automated radio telemetry to track Hawaiian forest birds from three dietary guilds in a continuous forest, and in a similar forest that was naturally fragmented in the 1800s by lava flows but supports stable populations of native birds. We generated kernel density profiles of activity (KDEs) over the full tracking period of each bird and used the KDEs to derive seven activity metrics that characterized daily activity patterns. We identified three distinct activity strategies using a cluster analysis of the activity metrics and assessed day-to-day variability in activity strategy to understand intraindividual consistency in activity behavior. We also evaluated the influence of landscape structure, dietary guild and sex on the suite of activity metrics using constrained ordination. Most birds (61%) exhibited high levels of sustained activity throughout the day, while 23% showed irregular activity most of the day followed by a peak in the late afternoon, and 16% were mainly active in the morning. Though activity patterns varied by sex and dietary guild, landscape structure had the strongest influence on activity patterns. Birds sustained high levels of activity throughout the day in the fragmented landscape regardless of dietary guild, suggesting they needed to be more active to obtain necessary resources. However, activity patterns of birds in the fragmented landscape varied more day-to-day, indicating they retained a method for adjusting behavior to match internal and external conditions. This study reveals how a diverse suite of tropical birds has adapted to long-term fragmentation in Hawaiʻi and demonstrates the utility of automated radio telemetry for studying the activity strategies of birds.

Hawaii↗
USGS2023

Landscape configuration alters movement behavior and space-use of a Hawaiian forest bird community

Habitat loss and fragmentation are considered the greatest threats to ecosystems worldwide. Movement reveals how individuals meet their habitat requirements and respond to environmental heterogeneity, and thus can provide a powerful tool for investigating how animals respond to changes in landscape configuration. In our study, we examined the effects of landscape configuration on the space use and movement strategies of four endemic Hawaiian forest bird species spanning a range of foraging guilds (i.e. frugivore, nectivore, generalist). We used a landscape-level automated radio tracking system to measure location data of 127 individuals tracked on Hawaiʻi Island in a naturally fragmented landscape created by volcanic activity in the mid- to late-1800s and a nearby continuous landscape. We found that landscape configuration had a strong effect on movement patterns and space-use of all four species. In the fragmented landscape, all species predominately occupied a single forest patch, displayed a high degree of area-restricted search behavior, with few long-distance movements away from their primary forest patch. These patterns contrasted significantly with those of conspecifics in the continuous landscape which exhibited relatively unconstrained movements across the forested landscape and had 3- to 12-fold larger home ranges. Our findings indicate that landscape structure plays a strong role in shaping movement behavior of a tropical bird community and provides valuable insights into the behavioral mechanisms that may be important for species to persist within fragmented landscapes.

Journal of Avian Biology↗
USGS2014

The effects of changing land cover on streamflow simulation in Puerto Rico

This study quantitatively explores whether land cover changes have a substantive impact on simulated streamflow within the tropical island setting of Puerto Rico. The Precipitation Runoff Modeling System (PRMS) was used to compare streamflow simulations based on five static parameterizations of land cover with those based on dynamically varying parameters derived from four land cover scenes for the period 1953-2012. The PRMS simulations based on static land cover illustrated consistent differences in simulated streamflow across the island. It was determined that the scale of the analysis makes a difference: large regions with localized areas that have undergone dramatic land cover change may show negligible difference in total streamflow, but streamflow simulations using dynamic land cover parameters for a highly altered subwatershed clearly demonstrate the effects of changing land cover on simulated streamflow. Incorporating dynamic parameterization in these highly altered watersheds can reduce the predictive uncertainty in simulations of streamflow using PRMS. Hydrologic models that do not consider the projected changes in land cover may be inadequate for water resource management planning for future conditions.

Journal of the American Water Resources Associatio↗
USGS2015

Shaping species with ephemeral boundaries: The distribution and genetic structure of desert tortoise ( Gopherus morafkai ) in the Sonoran Desert region

Aim We examine the role biogeographical features played in the evolution of Morafka's desert tortoise ( Gopherus morafkai ) and test the hypothesis that G. morafkai maintains genetically distinct lineages associated with different Sonoran Desert biomes. Increased knowledge of the past and present distribution of the Sonoran Desert region's biota provides insight into the forces that drive and maintain its biodiversity. Location Sonoran Desert biogeographical region; Sonora and Sinaloa, Mexico and Arizona, USA. Methods We examined wild tortoises from Mexico ( n = 155) and Arizona ( n = 78), spanning their known distribution. We used mtDNA sequences to reconstruct matrilineal relationships and 25 microsatellite (STR) loci for Bayesian analyses of gene flow. We performed clinal analyses on both mtDNA and STR loci to determine the position and amount of introgression where lineages co-occur. We used GIS to assess the association of genetic structuring with ecological features. We used these data in a hypothesis-driven approach to assess different models of how genetic diversity is maintained and distributed in G. morafkai . Results Gopherus morafkai was found to comprise genetically and geographically distinct ‘Sonoran’ and ‘Sinaloan’ lineages. Both lineages occurred in a relatively narrow zone of overlap in Sinaloan thornscrub, where it transitions into Sonoran desertscrub. Limited introgression occurred at the contact zone. The best-fit model suggests that these lineages diverged in parapatry where the distribution of genotypes is environment-dependent and introgression is inhibited by exogenous selection. Main conclusions The historically shifting ecotone between tropical deciduous forest and Sonoran desertscrub appears to be a boundary that fostered divergence between parapatric lineages of tortoises. The sharp genetic cline between the two lineages suggests that periods of isolation in temporary refugia due to Pleistocene climatic cycling influenced divergence. Despite incomplete reproductive isolation, the Sonoran and Sinaloan lineages of G. morafkai are on separate evolutionary trajectories.

Arizona, Sonora↗
USGS2020

At Palmyra Atoll, the fish‐community environmental DNA signal changes across habitats but not with tides

At Palmyra Atoll, the environmental DNA (eDNA) signal on tidal sand flats was associated with fish biomass density and captured 98%–100% of the expected species diversity there. Although eDNA spilled over across habitats, species associated with reef habitat contributed more eDNA to reef sites than to sand‐flat sites, and species associated with sand‐flat habitat contributed more eDNA to sand‐flat sites than to reef sites. Tides did not disrupt the sand‐flat habitat signal. At least 25 samples give a coverage >97.5% at this diverse, tropical, marine system.

Journal of Fish Biology↗
USGS2015

Tree mortality from drought, insects, and their interactions in a changing climate

Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated with two guilds of insects – bark beetles and defoliators – which are responsible for substantial tree mortality. We then discuss cross-biome patterns of insect-driven tree mortality and draw upon available evidence contrasting the prevalence of insect outbreaks in temperate and tropical regions. We conclude with an overview of tools and promising avenues to address major challenges. Ultimately, a multitrophic approach that captures tree physiology, insect populations, and tree–insect interactions will better inform projections of forest ecosystem responses to climate change.

New Phytologist↗
USGS2015

Incorporating phosphorus cycling into global modeling efforts: a worthwhile, tractable endeavor

Myriad field, laboratory, and modeling studies show that nutrient availability plays a fundamental role in regulating CO 2 exchange between the Earth's biosphere and atmosphere, and in determining how carbon pools and fluxes respond to climatic change. Accordingly, global models that incorporate coupled climate–carbon cycle feedbacks made a significant advance with the introduction of a prognostic nitrogen cycle. Here we propose that incorporating phosphorus cycling represents an important next step in coupled climate–carbon cycling model development, particularly for lowland tropical forests where phosphorus availability is often presumed to limit primary production. We highlight challenges to including phosphorus in modeling efforts and provide suggestions for how to move forward.

New Phytologist↗
USGS2016

Linking dominant Hawaiian tree species to understory development in recovering pastures via impacts on soils and litter

Large areas of tropical forest have been cleared and planted with exotic grass species for use as cattle pasture. These often remain persistent grasslands after grazer removal, which is problematic for restoring native forest communities. It is often hoped that remnant and/or planted trees can jump-start forest succession; however, there is little mechanistic information on how different canopy species affect community trajectories. To investigate this, I surveyed understory communities, exotic grass biomass, standing litter pools, and soil properties under two dominant canopy trees— Metrosideros polymorpha (‘ōhi‘a) and Acacia koa (koa)—in recovering Hawaiian forests. I then used structural equation models (SEMs) to elucidate direct and indirect effects of trees on native understory. Native understory communities developed under ‘ōhi‘a, which had larger standing litter pools, lower soil nitrogen, and lower exotic grass biomass than koa. This pattern was variable, potentially due to historical site differences and/or distance to intact forest. Koa, in contrast, showed little understory development. Instead, data suggest that increased soil nitrogen under koa leads to high grass biomass that stalls native recruitment. SEMs suggested that indirect effects of trees via litter and soils were as or more important than direct effects for determining native cover. It is suggested that diverse plantings which incorporate species that have high carbon to nitrogen ratios may help ameliorate the negative indirect effects of koa on natural understory regeneration.

Hawai‘i↗
USGS2016

Evaluating nest supplementation as a recovery strategy for the endangered rodents of the Florida Keys

The Key Largo woodrat ( Neotoma floridana smalli ) and Key Largo cotton mouse ( Peromyscus gossypinus allapaticola ) are federally endangered subspecies endemic to the tropical hardwood hammocks of Key Largo, Florida. Woodrats are considered generalists in habitat and diet, yet a steady decline in natural stick nests and capture rates over the past several decades suggests that they are limited by the availability of nesting habitat due to habitat loss and fragmentation. The more specialized Key Largo cotton mouse appears to rely on old growth hammock, a habitat type that is rare following past land clearing. In 2004, the U.S. Fish and Wildlife Service started building supplemental nest structures to restore habitat quality and connectivity for these endangered rodents, but nest use requires evaluation. We used camera traps and occupancy models to evaluate the factors influencing woodrat and cotton mouse use of the supplemental nests. We detected woodrats at 65 and cotton mice at 175 of 284 sampled nest structures, with co-occurrence at 38 nests. Woodrat nest use followed a gradient from low nest use in the north to high nest use in the south, which might relate to the proximity of free-ranging domestic cat ( Felis catus ) colonies in residential developments. Cotton mouse nest use, however, was related positively to mature hammock and related negatively to disturbed areas (e.g. scarified lands). The two species occurred independently of each other. Stick-stacking behavior was observed at supplemental nests and, although it was correlated with detection of woodrats, it was not a strong predictor of their occurrence. We suggest that nest supplementation can be an important tool for species recovery as habitat quality continues to improve with succession.

Florida↗
USGS2017

Rapid colonization of a Hawaiian restoration forest by a diverse avian community

Deforestation of tropical forests has led to widespread loss and extirpation of forest bird species around the world, including the Hawaiian Islands which have experienced a dramatic loss of forests over the last 200–800 years. Given the important role birds play in forest ecosystem functions via seed dispersal and pollination, a bird community's response to forest restoration is an important measure of the success of such conservation actions. We evaluated the bird response to reforestation at an important bird sanctuary, Hakalau Forest National Wildlife Refuge, Hawai′i Island, using 26 years of bird count data. We show that most species from within the diverse avian community increased significantly, but species colonized the restoration forest at different rates. Distance from intact forest and time since restoration were both important predictors of colonization rate, interacting such that for most species it took more time to colonize areas farther from the intact forest. In addition, both forest cover and understory diversity helped to explain bird densities, but the effect varied among species, suggesting that different habitat requirements may help drive variation in colonization rates. This article provides the first detailed evaluation of how a diverse community of birds has responded to one of the largest, ongoing reforestation projects in Hawai′i.

Hawai′i↗
USGS2019

Jump-starting coastal wetland restoration: A comparison of marsh and mangrove foundation species

During coastal wetland restoration, foundation plant species play a critical role in creating habitat, modulating ecosystem functions, and supporting ecological communities. Following initial hydrologic restoration, foundation plant species can help stabilize sediments and jump-start ecosystem development. Different foundation species, however, have different traits and environmental tolerances. To understand how these traits and tolerances impact restoration trajectories, there is a need for comparative studies among foundation species. In subtropical and tropical climates, coastal wetland restoration practitioners can sometimes choose between salt marsh and/or mangrove foundation species. Here, we compared the early life history traits and environmental tolerances of two foundation species: (1) a salt marsh grass (Spartina alterniflora), and (2) a mangrove tree (Avicennia germinans). In an 18-month study of a recently-restored coastal wetland in southeastern Louisiana (USA), we examined growth and survival along an elevation gradient and compared expansion and recruitment rates. We found that the rapid growth, expansion, and recruitment rates of the salt marsh grass make it a better species for quickly establishing ecological structure at suitable elevations. The slower growth, limited expansion, and lower recruitment of the mangrove species show its limited capacity for immediate structural restoration, especially in areas where it co-occurs with perennial salt marsh foundation species. Our findings suggest that the structural attributes needed in recently-restored areas (e.g., erosion control, vegetation structure) can be achieved more quickly using fast-growing foundation marsh species. Following salt marsh grass establishment, mangroves can then be used to further assist ecosystem development. This work highlights how appropriate foundation species can help jump-start ecosystem development to meet restoration objectives.

Restoration Ecology↗