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Data from: Anthropogenic disturbance of tropical forests threatens pollination services to açaí palm in the Amazon river delta
The açaí palm Euterpe oleracea Mart. in the Amazon river delta has seen rapid expansion to meet increased demand for its fruit. This has been achieved by transforming lowland forest habitats (floodplains) into simplified agroforests and intensive plantation in upland areas. As açaí palm makes an important contribution to the economy and food security of local communities, identifying management approaches that support biodiversity and ecosystem processes that underpin fruit production on açaí farms is essential. We compared flower-visitor communities and açaí fruit production in floodplain forests and upland plantations, across gradients of local management intensity (i.e. açaí density per ha) and surrounding forest cover. The relative contribution of biotic pollination and degree of pollen limitation were assessed using insect exclusion and hand-pollination experiments. We found that açaí flower visitors are highly diverse (c. 200 distinct taxa) and had variable responses to disturbance. Bee visitation was higher in floodplains and positively related to surrounding forest cover, but other flower visitors, including specialised curculionid beetles, were unresponsive to changes in surrounding forest cover. However, intensive management practices (i.e. high açaí palm densities) in floodplains and uplands had contrasting effects on flower-visitor communities, with flower-visitor richness being lower on intensively managed floodplain farms and ant densities being higher on intensive upland farms. Pollination experiments revealed açaí palm to be highly dependent on biotic pollination. Fruit set in open-pollinated inflorescences was positively related to flower-visitor richness and specialised curculionid beetle visitation, whereas the presence of ants on inflorescences had a negative effect. Synthesis and applications. Our study shows that pollinators are essential for açaí fruit production, but that intensive farming practices have eroded the relationship between surrounding forest cover and ecosystem function in floodplains (i.e. conversion of native forest into simplified agroforests) and increased the frequency of antagonistic interactions in uplands (e.g. high ant densities). These findings underline the value of extensive management practices, such as the maintenance of other tree species within farms and adjacent unmanaged forest patches, to ensure the long-term sustainability of açaí fruit production in the Amazon river delta.
Data from: Lianas reduce carbon accumulation and storage in tropical forests
Tropical forests store nearly 30% of global terrestrial carbon and contribute to 40% of the global terrestrial carbon sink. By affecting tree growth and survival, lianas impact the carbon balance of these forests. Here we demonstrate with a 3-y experiment that lianas substantially reduce forest-level carbon uptake and storage. This study is, to our knowledge, the first direct demonstration of liana effects at the ecosystem scale and illustrates the important role of lianas in tropical forests, particularly with respect to carbon budgets. Lianas are increasing in biomass and productivity throughout the tropics, and thus our findings have even greater relevance in terms of the fate of the tropical carbon balance, as well as for global atmospheric CO2 levels, in a changing climate.
Data from: Growth responses to soil water potential indirectly shape local species distributions of tropical forest seedlings
1. Local tree species distributions in tropical forests correlate strongly with soil water availability. However, it is unclear how species distributions are shaped by demographic responses to soil water availability. Specifically, it remains unknown how growth affects species distributions along water availability gradients relative to mortality. 2. We quantified spatial variation in dry season soil water potential (SWP) in the moist tropical forest on Barro Colorado Island, Panama, and used a hierarchical Bayesian approach to evaluate relationships between demographic responses of naturally regenerating seedlings to SWP (relative growth rates and first-year mortality) and species distributions along the SWP gradient for 62 species. We also tested whether species that were more abundant at the wet or dry end of the gradient performed better (1) at their 'home end' of the gradient ('best at home' hypothesis) and (2) 'at home' compared to co-occurring species ('home advantage' hypothesis). 3. Four and five species responded significantly to SWP in terms of growth or mortality, respectively. Growth (but not mortality) responses were positively related to species distributions along the SWP gradient; species with a more positive (negative) growth response to SWP were more abundant at higher (lower) SWP, i.e. at wetter (drier) sites. In addition, wet distributed species grew faster on the wet end of the SWP gradient than on the dry end ('best at home') and grew faster on the wet end than dry distributed species ('home advantage'). Mortality rates declined with seedling size for all species. Thus, seedling growth responses to SWP indirectly shaped local species distributions by influencing seedling size and thereby mortality risk. 4. Synthesis. By demonstrating how growth responses to spatial variation in soil water availability affect species distributions, we identified a demographic process underlying niche differentiation on hydrological gradients in tropical forests. Recognizing the role of these growth responses in shaping species distributions should improve understanding of tropical forest composition and diversity along rainfall gradients and with climate change.
Data from: Frugivory-related traits promote speciation of tropical palms
Animal-mediated seed dispersal by frugivorous birds and mammals is central to the ecology and functioning of ecosystems, but whether and how frugivory-related traits have affected plant speciation remains little explored. Fruit size is directly linked to plant dispersal capacity and therefore influences gene flow and genetic divergence of plant populations. Using a global species-level phylogeny with comprehensive data on fruit sizes and plant species distributions, we test whether fruit size has affected speciation rates of palms (Arecaceae), a plant family characteristic of tropical rainforests. Globally, the results reveal that palms with small fruit sizes have increased speciation rates compared with those with large (megafaunal) fruits. Speciation of small-fruited palms is particularly high in the understory of tropical rainforests in the New World, and on islands in the Old World. This suggests that frugivory-related traits in combination with geography and the movement behaviour of frugivores can influence the speciation of fleshy-fruited plants.
Data from: Fine partitioning of epiphyte habitat within Johansson zones in tropical Australian rainforest trees
For over three decades, the Johansson zones have been widely used in epiphyte studies as a way of stratifying the host tree into habitat zones, however, the usefulness of this system has been questioned. We test the effectiveness of the Johansson zones by grouping epiphyte species by the substrate and microclimatic attributes of their individual occurrences and assessing the fidelity of these groups to the Johansson zones. Habitat characteristics were recorded for every individual epiphyte on 30 trees in the lower montane rainforests of north-eastern Australia. Twenty-four epiphyte species were agglomerated into four groups using Ward's method. Group 4 was highly distinct and included shade loving species and nomadic vines from the lower zones of the host trees. Group 3 contained species from the most exposed habitats. Group 1 had higher light levels and lower substrate thickness than Group 2, yet both groups had close to identical distributions over the Johansson zones. This suggests that groups of epiphyte species may utilise different micro-sites within the same zone. While the Johansson zones are a useful tool in epiphyte studies, finer partitioning of habitat within the host tree may be missed.
Data from: High tolerance of tropical sapling growth and gas exchange to moderate warming
The effects of global warming on tropical forest growth and carbon storage are uncertain. While observations on canopy trees indicate negative correlations between temperature and growth, some seedling studies suggest the opposite. These contrasting results may reflect ontogenetic differences in temperature responses, or differences between the performance of potted plants under controlled conditions and plants under more variable conditions in the field. To try to bridge the gap between highly-controlled experiments on small seedlings and field observations on canopy trees we conducted two sets of outdoor experiments on saplings up to 2.5 m tall; one set to study the effects of night warming, and another set on the effects of day warming. To test the hypothesis that night warming would reduce growth in tropical saplings through stimulation of respiration, we grew the early-successional species Ochroma pyramidale in large 380-liter soil containers under ambient nighttime temperature and ambient +4.5°C. To test the hypothesis that day warming would reduce growth by reducing photosynthesis we compared plants in multi-species and single-species mesocosms rooted in the ground under ambient and passively warmed daytime conditions. In all experiments we monitored growth and measured foliar physiology and plant biomass allocation. Neither night warming nor day warming significantly affected biomass accumulation and allocation. Height growth increased with night warming in Ochroma pyramidale, but decreased with day warming in late-successional species. Night warming resulted in acclimation of dark respiration. Day warming resulted in acclimation of photosynthesis in early-successional species, but warming decreased photosynthesis in late-successional tree species. The seedling-to-sapling transition is a critical stage in the life of trees. We found no evidence that in this juvenile growth phase moderate increases in mean temperature reduce the performance of tropical trees, although increases in peak daytime temperature may negatively impact photosynthesis, especially in late-successional species.
Data from: Ecology of the growth of Anolis nebulosus (Squamata: Dactyloidae) in a seasonal tropical environment in the Chamela region, Jalisco, Mexico
Juvenile growth rates are thought to be restricted by available food resources. In animals that grow throughout the year, such as tropical lizards, growth is therefore predicted to be faster during the rainy season. We test this prediction using a population of Anolis nebulosus by describing the growth trajectories of both sexes using nonlinear regression models, and we then correlate the growth rates of individuals with food available in the environment, precipitation and temperature. The Von Bertalanffy model fit the growth rates of the females better, while the logistic-by-length model fit the males better. According to both models, the males grew faster than females, reaching slightly smaller sizes at adulthood. Males reached sexual maturity when 35 mm long, at an age of seven months, and females matured at 37 mm (SVL), taking nine months to reach this size. In 1989, juvenile males and females grew more in both seasons (rainy and dry) than adults; for 1990 there were no differences by season or between age classes. These results are interesting since in the 1989 and 1990 rainy seasons, practically the same orders of prey and the greatest abundance of prey available in the environment were registered. A possible explanation could be that predation was more intense in 1990 than in 1989. The influence of food, temperature and humidity in A. nebulosus shows little evidence to support our working hypothesis, mainly due to the low growth variation observed in 1990, so, we believe that the growth pattern of this species can be a complex combination of ecological and genetic factors.
Data from: Basal metabolism in tropical birds: latitude, altitude, and the "pace of life"
1. Life history varies across latitudes, with the 'pace of life' being 'slower' in tropical regions. Because life history is coupled to energy metabolism via allocation tradeoffs and links between performance capacity and energy use, low metabolic intensity is expected in tropical animals. Low metabolism has been reported for lowland tropical birds, but it is unclear if this is due to 'slow' life history or to a warm, stable environment. 2. We measured Basal Metabolic Rates (BMR) of 253 bird species across a 2.6 km altitude gradient in Peru. We predicted higher BMR at high altitude due to lower temperatures leading to elevated thermoregulatory costs. We also tested for BMR differences between widely separated tropical regions (Peru and Panama), and between tropical- and temperate-breeding birds. 3. We found no effect of altitude on BMR in Peruvian species and no difference in BMR between Peruvian and Panamanian birds, suggesting that BMR in Neotropical birds is consistent and independent of environmental temperature. In a dataset encompassing more than 500 species, tropical birds had significantly lower BMR than temperate-breeding birds. 4. In contrast to several recent analyses, we found higher BMR in passerine birds than in non-passerines, independent of breeding latitude. 5. Breeding latitude affects BMR, but diversity in avian life history within and between temperate and tropical regions may explain some of the residual variation in BMR after accounting for body mass and breeding latitude. Future studies of links between life history, metabolism, and environmental factors might benefit from examining these variables within individual species as well as across broad geographic contrasts.
Data from: Habitat preference and den characterization of Indian Pangolin (Manis crassicaudata) in a tropical lowland forested landscape of southwest Sri Lanka
The Indian pangolin (Manis crassicaudata) is under threat due to hunting for local consumption and illegal trafficking of scales and meat. The dearth of scientific studies on the ecology of the M. crassicaudata has impaired accurate assessments of its conservation needs. This study investigated the habitat preference and burrow characteristics of M. crassicaudata in a tropical lowland rainforest in southwest Sri Lanka. A total of 75 burrows (54 feeding burrows and 21 resting burrows) of M. crassicaudata in four different habitat types i.e. secondary forest, Pine-dominated forest, rubber cultivations and tea-dominated home gardens bordering forest were observed using fixed-width transects in order to characterize resting and feeding burrows of this species. The highest density of resting burrows was recorded from the secondary forest (4ha-1), followed by rubber cultivations (2.5ha-1) while no resting burrows were recorded in Pine-dominated forest and tea-dominated home gardens bordering forest. Feeding burrows were more abundant in Pine-dominated forest (5.7ha-1). The burrow depth, burrow opening height and width were significantly larger in resting burrows compared to feeding burrows. Resting burrows were located at higher elevations (75-100m) with moderately high slopes (450-600), dense canopy cover (>75%) and away from human habitation. Feeding burrows showed a greater variability in terms of associated environmental features. The study further revealed that Indian pangolins exclusively prefer habitat with rocks and boulders under which they dig resting burrows while the location of feeding burrows largely overlaps with the distribution of prey species. The resting burrow design consisted of a bending tunnel that initially slopes downward and then gradually inclines at an angle between 20 and 300, leading to the resting chamber. Our study highlights the importance of conserving fragmented secondary natural forests in changing landscapes of the southwest lowlands of Sri Lanka as these habitats appear to be critical to sustaining populations of M. crassicaudata.
Data from: Evidence for ecological divergence across a mosaic of soil types in an Amazonian tropical tree: Protium subserratum (Burseraceae)
Soil gradients are known to be an important driver of divergent natural selection in plant populations. Neotropical trees have the highest diversity on earth and it is not uncommon to find soil specialist congeners distributed parapatrically. Nevertheless very little is known about the role that edaphic heterogeneity plays in the origin and maintenance of tropical tree diversity. We predict that the mosaic of different soils in the lowland Amazon rainforest play a major role in generating and maintaining genetic variation in tropical tree populations through ecological divergence. This study examines genetic and morphological differentiation in the tropical tree Protium subserratum populations growing on the mosaic of white-sand, brown-sand and clay soil types distributed parapatrically throughout the western Amazon basin. We use nuclear microsatellites and vegetative characters to answer four major questions: (1) Are populations phenotypically and genetically differentiated across all three habitat types? (2) Can we detect a signature of natural selection over drift divergence among populations on different soil types? (3) What is the extent of hybridization and introgression across habitat types? (4) What is the relative importance of spatial distance and soil type in structuring P. subserratum tree populations and influencing migration rates among populations? We found significant morphological variation in populations across the three soil types. Higher levels of genetic differentiation and lower levels of gene flow were observed between adjacent populations found on different soil types than between geographically distant populations on the same soil type. Comparisons of phenotypic and neutral genetic variation among soil specialist populations suggest a role for natural selection in population divergence and a small number of hybrid individuals were detected between soil ecotypes showing that gene flow among populations may be occurring at a low frequency. Our results suggest that edaphic specialization in P. subserratum populations has occurred across multiple soil boundaries. While we cannot discern which factors caused initial divergence our results do suggest that natural selection is plays an important role in maintaining the integrity of populations across ecological boundaries and that edaphic specialization may be a general mechanism that promotes and maintains Amazonian tree diversity.
Data from: Linking vital rates of landbirds on a tropical island to rainfall and vegetation greenness
Remote tropical oceanic islands are of high conservation priority, and they are exemplified by range-restricted species with small global populations. Spatial and temporal patterns in rainfall and plant productivity may be important in driving dynamics of these species. Yet, little is known about environmental influences on population dynamics for most islands and species. Here we leveraged avian capture-recapture, rainfall, and remote-sensed habitat data (enhanced vegetation index [EVI]) to assess relationships between rainfall, vegetation greenness, and demographic rates (productivity, adult apparent survival) of three native bird species on Saipan, Northern Mariana Islands: rufous fantail (Rhipidura rufifrons), bridled white-eye (Zosterops conspicillatus), and golden white-eye (Cleptornis marchei). Rainfall was positively related to vegetation greenness at all but the highest rainfall levels. Temporal variation in greenness affected the productivity of each bird species in unique ways. Predicted productivity of rufous fantail was highest when dry and wet season greenness values were high relative to site-specific 5-year seasonal mean values (i.e., relative greenness); while the white-eye species had highest predicted productivity when relative greenness contrasted between wet and dry seasons. Survival of rufous fantail and bridled white eye was positively related to relative dry-season greenness and negatively related to relative wet-season greenness. Bridled white-eye survival also showed evidence of a positive response to overall greenness. Our results highlight the potentially important role of rainfall regimes in affecting population dynamics of species on oceanic tropical islands. Understanding linkages between rainfall, vegetation, and animal population dynamics will be critical for developing effective conservation strategies in this and other regions where the seasonal timing, extent, and variability of rainfall is expected to change in the coming decades.
Data from: Pulsing hydrology determines top-down control of basal resources in a tropical river-floodplain ecosystem
Variable hydrology of rivers strongly affects biophysical factors that influence primary production and population densities, thereby affecting the relative influence of bottom-up and top-down processes in trophic networks. Many tropical floodplain rivers have sustained seasonal flood pulses driven by precipitation patterns of the Intertropical Convergence Zone. These changes in flow alter concentrations of dissolved nutrients, aquatic primary productivity, and per-unit-area densities of aquatic organisms. Therefore, one would predict that the strength of top-down effects of animals on basal resources should shift as the annual flood pulse progresses. We conducted a series of field experiments in a Neotropical lowland river to test for effects of hydrologic phase, habitat (in-channel vs. floodplain aquatic habitat), and benthic feeding fish and meiofauna on particulate organic matter, chlorophyll, and benthic microalgae. Net ecosystem productivity of this oligotrophic river is higher during the low phase of the annual flood cycle, which is also when resident fishes are at highest densities and there is a seasonal influx of migratory benthic feeding fish. We therefore hypothesized that top-down effects of benthic-feeding fish would fluctuate temporally, with strongest effects during low water levels. We found that fish controlled the abundance of particulate organic matter and algae on solid substrates, but not on sand, during falling- and low-water phases within both channel and floodplain habitats. Except for diatom assemblages, which responded to fish exclusion, the taxonomic structure of algal and meiofauna assemblages was not significantly influenced by fish exclusion treatments, but varied in relation to habitat type and hydrologic phase. Meiofauna densities were highest during the low-water period; experimental exclusion of meiofauna during this period had a significant effect on accumulation of particulate organic matter in sand. By controlling abundance of important basal resources, fishes and meiofauna have large potential to influence other components of this tropical ecosystem. Our findings emphasize the predictable, gradual, changes in consumer-resource interactions associated with the seasonal flood pulse in tropical river systems.
Data from: Yet another empty forest: considering the conservation value of a recently established tropical nature reserve
The primary approach used to conserve tropical biodiversity is in the establishment of protected areas. However, many tropical nature reserves are performing poorly and interventions in the broader landscape may be essential for conserving biodiversity both within reserves and at large. Between October 2010 and 2012, we conducted bird surveys in and around a recently established nature reserve in Xishuangbanna, China. We constructed a checklist of observed species, previously recorded species, and species inferred to have occurred in the area from their distributions and habitat requirements. In addition, we assessed variation in community composition and habitat specificity at a landscape-scale. Despite the fact that the landscape supports a large area of natural forest habitat (~50,000 ha), we estimate that >40% of the bird fauna has been extirpated and abundant evidence suggests hunting is the primary cause. A large proportion (52%) of the bigger birds (>20 cm) were extirpated and for large birds there was a U-shaped relationship between habitat breadth and extirpation probability. Habitat specificity was low and bird communities were dominated by widespread species of limited conservation concern. We question whether extending tropical protected area networks will deliver desired conservation gains, unless much greater effort is channeled into addressing the hunting problem both within existing protected areas and in the broader landscape.
Data from: Evolution of woody life form on tropical mountains in the tribe Spermacoceae (Rubiaceae)
Spermacoceae are mainly an herbaceous group in the Rubiaceae. However, a few lineages are woody, and are found in a diverse range of habitat types. Three of the largest woody lineages (Arcytophyllum, Hedyotis, and Kadua) are characterized by their distribution in the moist tropical mountains, and have disjunct distribution patterns with respect to their closest relatives. In this study, we explore the cases of derived woodiness in these three lineages and their diversification dynamics in the tropical mountains of Asia, the Pacific, and the Americas. By combining phylogenetic results with wood anatomical studies, we estimated timing of origin of the three woody groups, inferred their ancestral traits and ancestral distribution ranges, analyzed their associations with the tropical upland habitat, and elucidated their diversification across tropical mountains. The three woody clades originated and diversified from herbaceous ancestors in close association with the tropical upland habitat during the Miocene. The ancestral range for Asian-Pacific Hedyotis and Pacific Kadua is Africa/Madagascar and continental Asia respectively. The complex geological history of tropical Asia allowed Hedyotis to diversify faster and create narrow endemics near oceans in the highlands of Western Ghats (India), Sri Lanka, Southeast Asia including southeastern China, and New Guinea. The three major woody clades in Spermacoceae have gained their woodiness independently from one another, subsequent to colonization by their ancestors from a different geographic environment. The evolution and diversification along the tropical mountain orogeny is strongly linked with the formation of woody habit and many narrow endemic species.
Data from: Female, but not male, tropical sparrows respond more strongly to the local song dialect: implications for population divergence.
In addition to the observed high diversity of species in the tropics, divergence among populations of the same species exists over short geographic distances in both phenotypic traits and neutral genetic markers. Divergence among populations suggests great potential for the evolution of reproductive isolation and eventual speciation. In birds, song can evolve quickly through cultural transmission resulting in regional dialects, which can be a critical component of reproductive isolation through variation in female preference. We examined female and male behavioral responses to local and non-local dialects in two allopatric populations of rufous-collared sparrows (Zonotrichia capensis) in the Andes of Ecuador. Here we show that female sparrows prefer their natal song dialect to the dialect from an allopatric population just 25 km away and separated by unsuitable higher elevation habitat (pass 4200 m), thus providing evidence of prezygotic reproductive isolation among populations. Males showed similar territorial responses to all conspecific dialects, with no consistent difference with respect to distance, making male territoriality uninformative for estimating reproductive isolation. This study provides novel evidence for culturally-based prezygotic isolation over very short distances in a tropical bird.
Data from: Reconciling timber extraction with biodiversity conservation in tropical forests using reduced-impact logging
1. Over 20% of the world's tropical forests have been selectively logged, and large expanses are allocated for future timber extraction. Reduced-impact logging (RIL) is being promoted as best practice forestry that increases sustainability and lowers CO2 emissions from logging, by reducing collateral damage associated with timber extraction. RIL is also expected to minimize the impacts of selective logging on biodiversity, although this is yet to be thoroughly tested. 2. We undertake the most comprehensive study to date to investigate the biodiversity impacts of RIL across multiple taxonomic groups. We quantified birds, bats and large mammal assemblage structures, using a before-after control-impact (BACI) design across 20 sample sites over a 5-year period. Faunal surveys utilized point counts, mist nets and line transects and yielded >250 species. We examined assemblage responses to logging, as well as partitions of feeding guild and strata (understorey vs. canopy), and then tested for relationships with logging intensity to assess the primary determinants of community composition. 3. Community analysis revealed little effect of RIL on overall assemblages, as structure and composition were similar before and after logging, and between logging and control sites. Variation in bird assemblages was explained by natural rates of change over time, and not logging intensity. However, when partitioned by feeding guild and strata, the frugivorous and canopy bird ensembles changed as a result of RIL, although the latter was also associated with change over time. Bats exhibited variable changes post-logging that were not related to logging, whereas large mammals showed no change at all. 4. Indicator species analysis and correlations with logging intensities revealed that some species exhibited idiosyncratic responses to RIL, whilst abundance change of most others was associated with time. 5. Synthesis and applications. Our study demonstrates the relatively benign effect of reduced-impact logging (RIL) on birds, bats and large mammals in a neotropical forest context, and therefore, we propose that forest managers should improve timber extraction techniques more widely. If RIL is extensively adopted, forestry concessions could represent sizeable and important additions to the global conservation estate – over 4 million km2.
Data from: Primary dermal fibroblasts and pectoralis muscle show similar patterns of oxidative stress in tropical and temperate birds despite differing life-histories
<p><span>Tropical birds have a "slower pace of life," with lower rates of whole-animal metabolism, smaller metabolically active organs, and lower cellular metabolic rates than their temperate counterparts. Oxidative stress is a physiological mechanism that may dictate differing life-histories such as those found between tropical and temperate birds. <span>Oxygen is required to make ATP, resulting in the production of reactive oxygen species (ROS)</span>. If left unchecked, ROS can structurally alter proteins, induce mutations in DNA, and damage structural lipids. To combat accumulating oxidative damage, organisms have evolved an elaborate and costly antioxidant system that serves to sequester ROS before they wreak cellular havoc. We examined whether oxidative stress would differ between tropical and temperate birds. We used isolated primary dermal fibroblasts and pectoralis muscle tissue for measurements. We measured four aspects of oxidative stress in primary fibroblasts – reduced glutathione (GSH) concentration, ROS production, mitochondrial content, and lipid peroxidation (LPO) damage. We found no significant differences in the four variables between temperate and tropical birds.. In muscle tissue, we measured catalase (CAT), superoxide dismutase (SOD) glutathione peroxidase (GPx) activity, peroxyl and hydroxyl scavenging capacity, and LPO damage. We found that peroxyl scavenging capacity was significantly higher in tropical birds compared with temperate birds. </span></p>
Data from: Short distance pollen dispersal and low genetic diversity in a subcanopy tropical rainforest tree, Fontainea picrosperma (Euphorbiaceae)
Gene flow via pollen movement affects genetic variation in plant populations and is an important consideration in plant domestication. Fontainea picrosperma is a subcanopy rainforest tree that is of commercial interest because it is the source of tigilanol tiglate, a natural product used for the treatment of solid tumors. We identify patterns of pollen-mediated gene flow within natural populations of F. picrosperma and estimate genetic parameters and genetic structure between adult and juvenile groups using microsatellite markers. Our results show pollination events occur over much shorter distances than reported for tropical canopy species. At least 63 % of seeds are sired by male trees located within 30 m of the mother. On average, 27 % of the local male population contributed to successful reproduction of F. picrosperma with most fathers siring a single seed, however, the contributions to reproduction were uneven. Larger male trees with more flowers had gre ater reproductive success than those with less flowers (P < 0.05). There were comparatively low levels of genetic variation across the species (HE = 0.405 for adult trees and 0.379 for juveniles) and we found no loss of genetic diversity between adult and juvenile trees. Short distance pollen flow and low genetic diversity is theoretically a prelude to genetic impoverishment, however F. picrosperma has persisted through multiple significant climatic oscillations. Nevertheless, the remaining low genetic diversity is of concern for domestication programs which require maximal genetic diversity to facilitate efficient selective breeding and genetic improvement of this commercially significant species.
Data from: Species richness-productivity relationships of tropical terrestrial ferns at regional and local scales
1. The species richness-productivity relationship (SRPR), by which the species richness of habitats or ecosystems is related to the productivity of the ecosystem or the taxon, has been documented both on regional and local scales, but its generality, biological meaning, and underlying mechanisms remain debated. 2. We evaluated the SRPR and 3 mechanistic hypotheses using terrestrial ferns in 18 study plots along an elevational gradient (500-4000 m) in Ecuador. We measured annual increases in above-ground biomass of 6175 fern individuals from 91 species over 2 years, and estimated plot-level tree productivity from increases in above-ground woody biomass of 560 trees. Analyses were conducted by (a) comparing plots along the elevational gradient (regional scale) and (b) comparing plots within each elevational belt (local scale). 3. Fern diversity was related to the productivity of the fern assemblages, but not to above-ground productivity of the trees. At the regional scale, we found a positive relationship of fern species richness to fern productivity that appeared to be determined by an increase in the number of fern individuals and niche availability. In contrast, at the local scale this relationship was negative and likely driven by interspecific competition. 4. Synthesis: Plot diversity of ferns appears to be limited by the number of available niches and competition to occupy these niches. At the local scale, this is reflected in a negative SRPR probably driven by competition, whereas with increasing scale the positive influence of productivity emerges. This represents the first evidence that productivity and competition affect the diversity of tropical herb assemblages at the plot scale.
Data from: Are landscape attributes a useful shortcut for classifying vegetation in the tropics? A case study of La Amistad International Park
Effective vegetation classification schemes identify the processes determining species assemblages and support the management of protected areas. They can also provide a framework for ecological research. In the tropics, elevation-based classifications dominate over alternatives such as river catchments. Given the existence of floristic data for many localities, we ask how useful floristic data are for developing classification schemes in species-rich tropical landscapes and whether floristic data provide support for classification by river catchment. We analyzed the distribution of vascular plant species within 141 plots across an elevation gradient of 130 to 3200 m asl within La Amistad National Park. We tested the hypothesis that river catchment, combined with elevation, explains much of the variation in species composition. We found that annual mean temperature, elevation, and river catchment variables best explained the variation within local species communities. However, only plots in high-elevation oak forest and Páramo were distinct from those in low- and mid-elevation zones. Beta diversity did not significantly differ in plots grouped by elevation zones, except for low-elevation forest, although it did differ between river catchments. None of the analyses identified discrete vegetation assemblages within mid-elevation (700–2600 m asl) plots. Our analysis supports the hypothesis that river catchment can be an alternative means for classifying tropical forest assemblages in conservation settings.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.