Find research datasets worth reusing

opencc-zeroJun 2022View details →

Highly-replicated soil, topography and vegetation sampling across an old-growth tropical rain forest landscape

Here we present data from highly-replicated sampling of soil, topography, and vegetation across an old-growth tropical rainforest landscape at the La Selva Biological Station, Costa Rica. Samples were taken at 100 x 50 m spacing using an existing surveyed grid system. The 573-ha sample area spanned a variety of soil, topographic and vegetation conditions, including flat terraces on old alluvial soil, ridge tops and steep slopes on residual soil, riparian habitats and fresh-water swamps. At each of 1170 grid points we established a circular 0.01 ha quadrat (radius = 5.64 m). We sampled soil at 30-50 cm depth with a soil augur and collected a sample for subsequent analysis. We measured slope angle with a clinometer and slope direction with a compass. We measured stem diameter to +1 mm with a synthetic fabric diameter tape for all stems >10 cm diameter (N= 5236) at 1.3 m from the ground or to ~ 6 m height if there were basal irregularities. We classified stems to life form (tree, palm, liana), and identified all trees and palms to species or morphospecies (N=266; lianas were not identified to species). We collected vouchers from all trees that we could not positively identify in the field (N=920). As a whole the data set presents an integrated view of soil, topography and vegetation across a mesoscale old-growth tropical rain forest landscape. The data have been used to refine a reserve-wide soils map for La Selva, and for a variety of papers analyzing the interactions of soil, topography and species distributions at landscape scales (see the 10 papers listed in the Related Works section below). There are no restrictions at all on the use of these data, and we think they will be useful for teaching and analysis projects as well as further original research applications. The data also provide a detailed benchmark of the status of old-growth vegetation in 1993-95 for one of the most intensively studied tropical rain forest landscapes in the world. Because the data are accurately georeferenced and detailed metadata on all methods are provided, this study could be repeated at any time to assess the trajectory of vegetation changes at La Selva, particularly in relation to local disturbances and changing regional and global climates.

opencc-zeroJun 2022View details →

Laying low: Rugged lowland rainforest preferred by feral cats in the Australian wet tropics

Invasive mesopredators are responsible for the decline of many species of native mammals worldwide. Feral cats have been causally linked to multiple extinctions of Australian mammals since European colonisation. While feral cats are found throughout Australia, most research has been undertaken in arid habitats, thus there is a limited understanding of feral cat distribution, abundance, and ecology in Australian tropical rainforests. We carried out camera-trapping surveys at 108 locations across seven study sites, spanning 200 km in the Australian Wet Tropics. Single-species occupancy analysis was implemented to investigate how environmental factors influence feral cat distribution. Feral cats were detected at a rate of 5.09 photographs/100 days, 11 times higher than previously recorded in the Australian Wet Tropics. The main environmental factors influencing feral cat occupancy were a positive association with terrain ruggedness, a negative association with elevation, and a higher affinity for rainforest than eucalypt forest. These findings were consistent with other studies on feral cat ecology but differed from similar surveys in Australia. Increasingly harsh and consistently wet weather conditions at higher elevations, and improved shelter in topographically complex habitats may drive cat preference for lowland rainforest. Feral cats were positively associated with roads, supporting the theory that roads facilitate access and colonisation of feral cats within more remote parts of the rainforest. Higher elevation rainforests with no roads could act as refugia for native prey species within the critical weight range. Regular monitoring of existing roads should be implemented to monitor feral cats, and new linear infrastructure should be limited to prevent encroachment into these areas. This is pertinent as climate change modelling suggests that habitats at higher elevations will become similar to lower elevations, potentially making the environment more suitable for feral cat populations.

opencc-by-4.0Jun 2022View details →

Data underlying the figures "Diabatic Upwelling in the Tropical Pacific: Seasonal and subseasonal variability"

Data for the figures in the paper Diabatic Upwelling in the Tropical Pacific: Seasonal and subseasonal variability

opencc-zeroJun 2022View details →

Individual growth of the Flathead Knobscaled Lizard, Xenosaurus platyceps, from tropical and temperate populations

Growth rates of ectotherms are frequently affected by environmental conditions, such as temperature, precipitation, and prey availability. However, local adaptation to environmental conditions could influence geographic variation in growth rates. We studied growth rates of the Flathead Knob-scaled Lizard, Xenosaurus platyceps, from a tropical population and a temperate population in Tamaulipas, Mexico. We used a field study and a common garden experiment to examine the extent and potential causes of variation in individual growth rates between these two populations from contrasting environments. Field-determined growth rates in the tropical population were greater than those in the temperate population. In a laboratory common garden experiment that manipulated food availability and temperature for neonates from each population, neonates from the tropical population grew faster than those from the temperate population. Neonates kept at higher temperatures grew faster than those kept at lower temperature. In addition, growth rates of neonates from temperate and tropical populations did not differ at low temperature, but neonates from the tropical population grew faster at the higher temperature than did the neonates from the temperate population. Food treatment did not affect individual growth rates in these lizards, although there was a trend for neonates grown with higher food availability to grow faster. Our results suggest that not only does the warm environment of the tropical population contribute to the observed differences in field growth rates, but there is a genetic difference in the ability of the tropical population to take advantage of the warmer temperatures to increase growth rates.

opencc-zeroJul 2022View details →

Are fine roots 'leaves underground' in terms of allometry? A test in a tropical forest successional series in southwest China

Fine roots have been hypothesized to be "leaves underground" in terms of vascular network, but this hypothesis has rarely been tested within the framework of metabolic scaling theory (MST). We measured average fine-root (diameter < 1 mm) mass (M), surface area (A), volume (V), diameter (D) and length (L) for 216 soil cores from 24 plots across four successional stages in tropical forests of Xishuangbanna (southwest China), and examined eight scaling relationships between these variables at the individual root scale. We tested whether fine-root allometries conformed to MST's model for leaf (MSTl) or model (MSTw) for woody organs (e.g. trunk). We also assessed the relative effects of environmental factors, tree size, species composition and diversity, and stand structural factors on allometric relationships using structural equation models (SEMs). Our results showed that: 1) Fine-root scaling exponents rarely conformed to MSTl's predictions. 2) The scaling exponents between fine-root M, A, V and D all conformed to MSTw's predictions in later successional forests, but showed greater deviation towards early successional stage. 3) The scaling exponents associated with fine-root length differed markedly from MSTw's predictions. 4) Changes of some fine-root scaling exponents across successional stage were mainly affected by tree size or soil fertility, and species composition affected allometry only indirectly via tree size. Our results suggested that the allometries of individual fine roots largely conform to the scaling rules governing woody organs instead of leaves, probably because leaves are nearly two-dimensional objects while the other two are three-dimensional. We showed that MSTw can well predict some fine-root allometries in later successional forests, suggesting great potential of utilizing MSTw to better estimate fine-root biomass and productivity. However, the present MSTw still needs to be improved for predicting the scaling relationships concerning fine-root length, and also for better quantifying allometric exponents in earlier successional forests.

openncgl-uk-2.0Jul 2022View details →

Mean sea-level pressure and related indices from control and tropical relaxation winter seasonal hindcasts using the Met Office GloSea5 system.

© Crown Copyright, Met Office The accompanying data is made available under the terms of the Non-Commercial Government Licence (http://www.nationalarchives.gov.uk/doc/non-commercial-government-licence/version/2/). These data are the results of ensemble modelling simulations using the Met Office GloSea5 numerical seasonal prediction system. Files in (zipped) netcdf format contain winter seasonal-mean mean sea-level pressure (MSLP) fields for each member of specified ensemble and hindcast winter (December-February from 1993-94 to 2015-16). The files are named according to the specification of relaxation towards observational reanalysis in each. HCAST has no relaxation, ALL has tropical (approximately 22.5S to 22.5N) relaxation at all atmospheric heights, TROP is similar to ALL but with relaxation limited to below 18km and STRAT is similar to ALL but with relaxation limited to above 18km. The relaxation is designed to constrain the atmospheric state to be close to that which was observed within the domain over which it is applied. Details of the technique can be found in Maidens et al., 2021* and references therein. An additional text file is provided to give summary statistics of key MSLP-based winter indices.   * Maidens, A., Knight, J. R., &  Scaife, A. A. (2021). Tropical and stratospheric influences on winter atmospheric circulation patterns in the North Atlantic sector. Environmental Research Letters, 16, 024035. https://doi.org/10.1088/1748-9326/abd8aa

opencecill-2.1Apr 2022View details →

Classification of tropical cyclone containing images using a convolutional neural network: performance and sensitivity to the learning dataset

NXTensor extraction library, experiment code, tropical cyclone and background images and their metadata generated from the meterological reanalysis ERA5 and MERRA-2 according to the HURDAT2 cyclone tracks. Version specifications: <ul> <li>NXTensor: v0.3.3.10</li> <li>Experiment code: v2.0.3</li> <li>Image sets: v1</li> </ul>

opencc-by-4.0Jul 2022View details →

Estimates of soil nutrient limitation on the CO2 fertilization effect for tropical vegetation

Data for CO2 fertilization experiments and CMIP6 model simulations used in publication: "Estimates of soil nutrient limitation on the CO2 fertilization effect for tropical vegetation"

Data for: Temperate and tropical lizards are vulnerable to climate warming due to increased water loss and heat stress

Climate warming has imposed profound impacts on species globally. Understanding the vulnerabilities of species from different latitudinal regions to warming climates is critical for biological conservation. Using five species of Takydromus lizards as a study system, we quantified physiological and life-history responses and geography range change across latitudes under climate warming. Using integrated biophysical models and hybrid species distribution models, we found: (1) thermal safety margin is larger at high latitudes, and is predicted to decrease under climate warming for lizards at all latitudes; (2) climate warming will speed up embryonic development and increase annual activity time of adult lizards, but will exacerbate water loss of adults across all latitudes; and (3) species across latitudes are predicted to experience habitat contraction under climate warming due to different limitations: tropical and subtropical species are vulnerable due to increased extremely high temperatures, whereas temperate species are vulnerable due to both extremely high temperatures and increased water loss. This study provides a comprehensive understanding of the vulnerability of species from different latitudinal regions to climate warming in ectotherms and also highlights the importance of integrating environmental factors, behavior, physiology, and life-history responses in predicting the risk of species to climate warming.

Tropical tree species differ in damage and mortality from lightning

Lightning is an important agent of mortality for large tropical trees with implications for tree demography and forest carbon budgets. We evaluated interspecific differences in susceptibility to lightning damage using a unique dataset of systematically located lightning strikes on Barro Colorado Island, Panama. We measured differences in mortality among trees damaged by lightning and related those to damage frequency and tree functional traits. Eighteen of 30 focal species had lightning mortality rates that deviated from null expectations. Several species showed little damage and 3 species had no mortality from lightning, whereas palms were especially likely to die from strikes. Species that were most likely to be struck also showed the highest survival. Interspecific differences in tree tolerance to lightning suggest that lightning-caused mortality shapes compositional dynamics over time and space. Shifts in lightning frequency due to climatic change are likely to alter species composition and carbon cycling in tropical forests.

Seasonal variation in impact of non-native species on tropical seed dispersal networks

Invasive non-native species can alter animal-mediated seed dispersal interactions and ultimately affect the stability of recipient communities. The degree of such disturbances, however, is highly variable and depends on several factors, two of which have received little attention: the relative timing of native and non-native fruiting phenologies, and the associated variation in relative resource availability across the fruiting period. Both are likely to alter plant-seed disperser interactions threatened by biological invasions. Here we investigated the impact of plant invasions on the seasonal dynamics of frugivory and seed dispersal networks across a large-scale experimental setup and a plant invasion gradient on a tropical island. We recorded fruit and frugivore abundances, and plant-frugivore interactions across 8 inselbergs (i.e. rocky outcrops) with different levels of plant invasion during 10 months on the island of Mahé, Seychelles. By combining four sampling methods of plant-frugivore interactions we constructed quantitative seed dispersal networks at all sites across two 5-month seasons: the on-peak and off-peak fruiting season. Our findings showed that, by fruiting mostly synchronously with natives, non-native plants compete with natives for dispersal services, predominantly carried out by native frugivores. Variation in native seed dispersal was driven by plant invasion and seasonality. Specifically, native seed dispersal declined with the degree of invasion; dispersal frequency increased with fruit abundance more strongly during the off-peak fruiting season; and networks became increasingly specialised during off-peak. These results indicated that during the main fruiting peak seed dispersal services were saturated, which likely intensified the competition between native and non-native fruits. When resources were scarce during off-peak fruiting season, native and non-native frugivores were more selective in their fruit choice at sites dominated by non-native plants. We showed that native plant and frugivore populations and native seed dispersal interactions were more vulnerable in invaded plant communities, where non-native plants compete with natives for dispersal services potentially reducing native recruitment. As invasive non-native plants dominate many ecosystems worldwide, particularly on islands, our findings showed that controlling plant invasions in vulnerable native communities can be critical to maintain native ecosystem functions and biodiversity.

opencc-zeroSep 2022View details →

Effects of canopy cover on fruiting intensity and fruit removal of a tropical invasive weed

Lantana camara (hereafter, Lantana) is among the worst invasive alien plants spread extensively across Africa, Australia and Asia at an alarming rate, posing significant challenges to conservation of native biodiversity. While, Lantana invasion is widely recognised to be more pronounced in open-canopy habitats (including deciduous forests, forest edges and gaps), the potential role of variation in seed dispersal across habitats varying in overstory canopy cover is poorly understood. Avian frugivores are among primary seed dispersers of the fleshy-fruited Lantana. We monitored 45 Lantana shrubs across a gradient of overstory canopy cover to determine the relationship between fruiting intensity and canopy cover. We watched 80 Lantana shrubs (240 h) across a canopy cover gradient to determine 1) differences in frugivore assemblage visiting Lantana across open- and closed-canopy habitats, 2) drivers of frugivore visitation on Lantana, and 3) relationship between seed disperser visitation rate and overstory canopy cover. We found that Lantana shrubs under low overstory canopy cover had higher fruit abundance than those in high canopy cover. Frugivore assemblage differed between Lantana shrubs in open- versus closed-canopy cover habitats. Drivers of frugivore visitation on Lantana varied across different frugivore species with a greater probability of occurrence of bulbuls (the primary seed dispersers of Lantana) on shrubs under low overstory canopy cover. Visitation rates of the effective seed dispersers were higher on shrubs under low overstory canopy cover. Thus, there was greater chances of dispersal of seeds in habitats with low overstory canopy cover. The study demonstrates variable fruiting intensity and fruit removal rate as a driver of differences in dispersal of seeds across habitats. It highlights greater vulnerability of open habitats to invasion and the need to prioritise Lantana management efforts in open habitats. Anthropogenic activities that lead to canopy openings (e.g. tree lopping and logging) likely facilitate Lantana invasion through greater fruit production and seed dispersal.

Crickets as indicators of ecological succession in tropical

Cricket (Ensifera, Grylloidea) are not commonly used as ecological indicators in contrary to other Orthoptera (e.g. grasshoppers and katydids). However, they are sensitive to environmental changes and abundant in tropical regions. To evaluate if crickets are relevant bioindicators of tropical ecosystems, we investigated cricket assemblages along a tropical ecological gradient. We collected crickets during both day and night in southern New Caledonia for three stages of an ecological succession: open shrubland, preforest and forest. Simultaneously, we measured several environmental variables, such as temperature and relative humidity, at each sampling site. Cricket species assemblages showed a clear response to ecological succession. The highest and lowest species richness and abundances of individuals were respectively found in forest and shrubland, with species specialized in each ecological stage revealing the conservation value of each of these stages. Similar results were found when considering only the part of cricket communities with ability to acoustically communicate. This work is part of a larger research program about Neocaledonian crickets and contributes to support the use of acoustic approaches to monitor tropical environments. In conclusion, these findings highlight the potential value of crickets as an environmental indicator in tropical ecosystems. The results also contribute to the discussion of the intrinsic conservational value of shrublands in New Caledonia and similar ecotypes.

Comparative efficacy of GS-Hv1a against invasive tropical tephritids

Invasive tephritid fruit flies collectively pose a significant economic challenge to agricultural pest management globally. Insecticide resistance to a number of previously effective chemical classes has increased the risk these pests pose as management options become limited. We evaluated the efficacy of a novel class of peptide-based biorational insecticides containing the active ingredient, GS-omega/kappa-Hxtx-Hv1a (Hv1a), against four of tephritid species, oriental fruit fly (Bactrocera dorsalis), melon fly (Zeugodacus cucurbitae), Mediterranean fruit fly (Ceratitis capitata, "Medfly"), and Malaysian fruit fly (B. latrifrons). This assessment aimed to determine whether Hv1a has the potential for effective management of tropical tephritids, particularly in regions where insecticide resistance has developed to other products. We conducted two sets of screening assays with different methods of exposure, oral and topical, and compared survival over time in response to increasing concentrations of Hv1a up to 3.86 mg/ml. We found that efficacy was species dependent: Ceratitis capitata was susceptible following topical exposure, while the other species of fruit fly were not. While Medfly was susceptible following oral ingestions as well, the dose required to achieve mortality was greater than topical. We observed that mortality continued to decline up to 72 hours after exposure, indicating a delayed effect similar to other reduced-risk insecticidal products such as fipronil. For this reason, Hv1a may be useful as a horizontal transfer tool in conjunction with C. capitata male pheromone lures.

Nombre de nits tropicals a la fase de maduració de la vinya al territori de la D.O. Penedès al llarg del segle XXI a l'escenari de canvi climàtic RCP 4.5 (format TIFF)

Distribució espacial del valor mitjà del nombre de nits tropicals a la fase de maduració de la vinya al territori de la D.O. Penedès per l’escenari de canvi climàtic moderat RCP 4.5 projectat per a les dècades dels anys 2030, 2050, 2070 i 2090. A dalt a l’esquerra es mostra l’escenari control on es representa el valor mitjà del període 1972-2005.

Nombre de nits tropicals a la fase de maduració de la vinya al territori de la D.O. Penedès al llarg del segle XXI a l'escenari de canvi climàtic RCP 8.5 (format TIFF)

Distribució espacial del valor mitjà del nombre de nits tropicals a la fase de maduració de la vinya al territori de la D.O. Penedès per l’escenari de canvi climàtic moderat RCP 8.5 projectat per a les dècades dels anys 2030, 2050, 2070 i 2090. A dalt a l’esquerra es mostra l’escenari control on es representa el valor mitjà del període 1972-2005.

opencc-zeroSep 2022View details →

Chronic browsing by an introduced mammalian herbivore in a tropical island alters species composition and functional traits of forest understory plant communities

Mammalian herbivores have large-scale impacts on vegetation, altering structure and species composition, especially in tropical grasslands and savannas. However, there is limited understanding of the potential impacts of mammalian herbivores in tropical wet forests, where they are typically less abundant. We investigated the effects of an introduced mammalian herbivore chital (Axis axis) on vegetation structure, composition and leaf functional traits of tropical evergreen forests of the Andaman Islands, India. Across seven islands, representing a gradient of herbivore densities, increasing chital presence was associated with decreased understory richness, understory density and adult tree richness, but was not related to adult tree density or size class distributions. We also found a significant decrease in community-level leaf palatability traits (specific leaf area decreased and leaf thickness increased) with increasing chital habitat use. This community-level shift in leaf trait values was better explained by intra-specific variation in leaf traits across islands rather than changes in species composition. In summary, we show persistent long-term impacts of an introduced mammalian herbivore on understory tropical tree communities although there is little impact on adult tree communities. Our results also show that functional traits of species can be altered in response to novel herbivory, even at herbivore densities where there are no detectable impacts on adult forest structure or composition. Such altered functional traits may potentially alter ecosystem functioning in these forests even without changes in vegetation structure.

Dataset to adjusted spectral correction method for calculating extreme winds in tropical cyclone affected water areas

This is a dataset of the 50-year wind of an effective temporal resolution of 10 min over three areas with the presence of tropical cyclones at 10 m, 50 m, 100 m and 150 m. There are 18 files in total, with 12 files for the 50-year winds: 'XXcfsru50atYYmcorr_revision.dat' and 6 files for the corresponding latitudes and longitudes: 'TC_XX_lat.dat' and 'TC_XX_lon.dat' The three areas are indexed as E1, W1, W2 (as in the file names 'XX'). The heights are 10 m, 50 m, 100 m and 150 m (as in the filenames 'YY').

TCRIP-MIM: Rapid Intensification Prediction for Tropical Cyclone by Combining Memory In Memory Network with Sequential Satellite Images

This is the official repository for the paper TCRIP-MIM: Rapid Intensification Prediction for Tropical Cyclone by Combining Memory In Memory Network with Sequential Satellite Images. We use the publicly available dataset from Taiwan University (Bai et al., 2019) as experimental data, consisting of four channels of TC satellite images with a temporal resolution of 3 hours, whose preprocessing method is also publicly available. We use infrared and passive microwave TC satellite image sequences for our experiments, each divided into 24-hour segments (8 infrared and 8 passive microwave satellite images, 16 in total), preprocessing and enhancing data as noted above, so there is no experimental error due to different data preprocessing methods. In this study, the 2003–2017 TC dataset from various global basins was divided into training (1097 TCs, 43528 events), validation (188 TCs, 7884 events), and test sets (94 TCs, 3196 events).