In Finland, the distribution area of the taiga tick, Ixodes persulcatus (Schulze, 1930), is neste... more In Finland, the distribution area of the taiga tick, Ixodes persulcatus (Schulze, 1930), is nested within a broader area of distribution of a congeneric species, the sheep tick, Ixodes ricinus (Linnaeus, 1758) (Acari: Ixodidae). We assess whether distinct environmental adaptations or dispersal history provides a more parsimonious explanation for the differences in the distributions of the two common and medically important ixodids in Finland. We used an innovative spatially constrained randomization procedure to analyze whether crowdsourced occurrence data points of the two tick species had statistically different associations with any of the 28 environmental variables. Using points of presence in a region of species co‐occurrence, we built Maxent models to examine whether environmental factors or dispersal history could explain the absence of I. persulcatus in a part of the range of I. ricinus in Finland. Five environmental variables—number of inhabitants, road length, elevation ab...
In Amazonian terra-firme non inundated forests, local floristic composition and species occurrenc... more In Amazonian terra-firme non inundated forests, local floristic composition and species occurrence are explained by water availability as determined by topographic conditions. Topographic complexity can render these conditions quite variable across the landscape and the effects on plant ecological responses are difficult to document. We used a set of topographically defined hydrological metrics to evaluate community composition and single-species responses of four plant groups [pteridophytes (ferns and lycophytes), Melastomataceae, palms (Arecaceae) and Zingiberales] to topographic conditions in the middle Juruá River region, in western Brazilian Amazonia. The area spans two geological formations (Içá and Solimões) with contrasting topography. River terraces are also found along the main rivers in the area. Local topographic conditions were approximated by height above the nearest drainage (HAND), slope, and Strahler´s drainage order, all obtained from a SRTM digital elevation model...
Silica is the best-known component filling the spaces that form phytoliths in many plants, but ph... more Silica is the best-known component filling the spaces that form phytoliths in many plants, but phytoliths may also contain other elements. We used scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX) to map element distributions in the leaves of Guadua bamboo, which is a successful competitor in southwestern Amazonian forests. We emphasize immobile elements that can be mineralized (silicon and calcium) as well as potassium, an abundant mobile nutrient with many vital functions. We discovered high silicon (Si) content with little or no calcium (Ca) or potassium (K) in bulliform cells, bilobate shaped short cells and stomata, all of which can form phytoliths, and moderately high Si content in the bundle sheet, prickle tips and papillae. K often surrounded Si-loaded cells, Si and K had overlapping distributions in the intercostal areas near vein margins, and Ca showed abundant spotted distribution in the intercostal areas. The dark inside content of the cost...
Forest structure determines light availability for understorey plants. The structure of lowland A... more Forest structure determines light availability for understorey plants. The structure of lowland Amazonian forests is known to vary over long edaphic gradients, but whether more subtle edaphic variation also affects forest structure has not beenresolved. In western Amazonia, the majority of non-flooded forests grow on soils derived either from relatively fertile sediments of the Pebas Formation or from poorer sediments of the Nauta Formation. The objective of this study was to compare structure and light availability in the understorey of forests growing on these two geological formations. We measured canopy openness and tree stem densities in three size classes in northeastern Peru in a total of 275 study points in old-growth terra firme forests representing the two geological formations. We also documented variation in floristic composition (ferns, lycophytes and the palm Iriartea deltoidea) and used Landsat TM satellite image information to model the forest structural and floristi...
Les modèles de distribution des plantes de la forêt pluvieuse de l'Amazonie sont peu connus à... more Les modèles de distribution des plantes de la forêt pluvieuse de l'Amazonie sont peu connus à cause d'une recherche botanique inadéquate et géographiquement inégale. Si les espèces végétales forment de manière récurrente des communautés écologiquement restreintes, il devrait y avoir des modèles de distribution récurrents qui pourraient être découverts en étudiant seulement une partie de la flore. Les comparaisons de la flore de douze terrains d'étude différents dans l'Amazonie péruvienne sur la base d'arbres supérieurs à 2,5 cm de diamètre à la hauteur de la poitrine, fougères terrestres et #Melastomataceae$, indiquent qu'il existe des communautés de plantes récurrentes et que les fougères et #Melastomataceae$ sont de très bons indicateurs de plusieurs modèles phytogéographiques généraux en Amazonie. (Résumé d'auteur)
Data on the Amazonian Malaise trapping carried out in 1998, 2000, 2008 and 2011 by the University... more Data on the Amazonian Malaise trapping carried out in 1998, 2000, 2008 and 2011 by the University of Turku. Flying insects were collected by Malaise traps in Peruvian Amazonia by Ilari Sääksjärvi and Isrrael Gómez. The dataset contains data on what samples were collected, on the trap sites, on the vegetation around the trap sites, and on the weather. More importantly, it contains information on how this data was compiled. There was no complete list of Amazonian Malaise samples before this, and the sample data had to be combined from multiple sources. This dataset is also described in the associated paper (link to come when published).
Species and soil data were collected in the field by the researchers mentioned as data providers ... more Species and soil data were collected in the field by the researchers mentioned as data providers for each plot. Reflectance data come from a Landsat TM/ETM+ image composite based on images acquired in 2000-2009 and processed using R code written by Jasper Van doninck. CHELSA and SRTM data come from respective online portals. See README file for explanation of the data contained in each column
Datasets of the dialect group analyses. Linguistic FST distances (sheet 1), geographical distance... more Datasets of the dialect group analyses. Linguistic FST distances (sheet 1), geographical distances (sheet 2) and raw data of 33 environmental and cultural variables (sheet 3) used in the analyses of the dialect groups. (XLS 52 kb)
Linguistic distances between municipalities. Rough equivalents of Séguy's dialect distance me... more Linguistic distances between municipalities. Rough equivalents of Séguy's dialect distance metric, i.e. a percentage of disagreeing linguistic features between pairs of municipal dialects. (CSV 1277 kb)
Aim: To map and interpret floristic and geoecological patterns across the Amazon basin by combini... more Aim: To map and interpret floristic and geoecological patterns across the Amazon basin by combining extensive field data with basin-wide Landsat imagery and climatic data Location: Amazonia Taxon: Ground truth data on ferns and lycophytes; remote sensing results reflect forest canopy properties Methods: We used field plot data to assess main ecological gradients across Amazonia and to relate floristic ordination axes to soil base cation concentration, CHELSA climatic variables and reflectance values from a basin-wide Landsat image composite with generalized linear models (GLM). Ordination axes were then predicted across all Amazonia using Landsat and CHELSA, and a regional subdivision was obtained using k-medoid classification. Results: The primary floristic gradient was strongly related to base cation concentration in the soil, and the secondary gradient to climatic variables. The Landsat image composite revealed a tapestry of broad-scale variation in canopy reflectance characteristics across Amazonia. Ordination axis scores predicted using Landsat and CHELSA variables produced spatial patterns consistent with existing knowledge on soils, geology and vegetation, but also suggested new floristic patterns. The clearest dichotomy was between central Amazonia and the peripheral areas, and the available data supported a classification into at least eight subregions. Main conclusions Landsat data are capable of predicting soil-related species compositional patterns of understory ferns and lycophytes across the Amazon basin with surprisingly high accuracy. Although the exact floristic relationships may differ among plant groups, the observed ecological gradients must be relevant for other plants as well, since surface reflectance recorded by satellites is mostly influenced by the tree canopy. This opens exciting prospects for species distribution modelling, conservation planning, and biogeographical and ecological studies on Amazonian biota. Our maps provide a preliminary geoecological subdivision of Amazonia that can now be tested and refined using field data of other plant groups and from hitherto unsampled areas
:Two core questions in plant community ecology are to what extent the distributions of species ar... more :Two core questions in plant community ecology are to what extent the distributions of species are structured by local environmental conditions, and whether taxa differ in this regard. We compared the distributions of trees, Melastomataceae and ferns on soil and topographic gradients in a Costa Rican lowland rain forest (trees and ferns 983 plots, Melastomataceae 277 plots). To test whether these plant groups differed in the prevalence or type of habitat specialization, we calculated species’ environmental optima and tolerances on each gradient. Habitat specialization was defined as a significantly biased optimum, or a narrow tolerance, relative to values obtained under spatially restricted randomizations of species occurrences. Within plant groups, we also asked whether the dispersion of species optima differed from random expectation on each gradient. Fern optima were over-dispersed on multiple gradients, implying considerable interspecific habitat partitioning, and tree optima were over-dispersed in relation to topographic position. Habitat specialization was more prevalent in the two predominantly understorey groups than in trees (75% of Melastomataceae species, 81–87% of ferns, 57–58% of trees). Species optima of Melastomataceae and ferns also tended towards lower landscape positions than did those of trees, perhaps reflecting a higher proportion of drought-sensitive species in these two groups.
In Finland, the distribution area of the taiga tick, Ixodes persulcatus (Schulze, 1930), is neste... more In Finland, the distribution area of the taiga tick, Ixodes persulcatus (Schulze, 1930), is nested within a broader area of distribution of a congeneric species, the sheep tick, Ixodes ricinus (Linnaeus, 1758) (Acari: Ixodidae). We assess whether distinct environmental adaptations or dispersal history provides a more parsimonious explanation for the differences in the distributions of the two common and medically important ixodids in Finland. We used an innovative spatially constrained randomization procedure to analyze whether crowdsourced occurrence data points of the two tick species had statistically different associations with any of the 28 environmental variables. Using points of presence in a region of species co‐occurrence, we built Maxent models to examine whether environmental factors or dispersal history could explain the absence of I. persulcatus in a part of the range of I. ricinus in Finland. Five environmental variables—number of inhabitants, road length, elevation ab...
In Amazonian terra-firme non inundated forests, local floristic composition and species occurrenc... more In Amazonian terra-firme non inundated forests, local floristic composition and species occurrence are explained by water availability as determined by topographic conditions. Topographic complexity can render these conditions quite variable across the landscape and the effects on plant ecological responses are difficult to document. We used a set of topographically defined hydrological metrics to evaluate community composition and single-species responses of four plant groups [pteridophytes (ferns and lycophytes), Melastomataceae, palms (Arecaceae) and Zingiberales] to topographic conditions in the middle Juruá River region, in western Brazilian Amazonia. The area spans two geological formations (Içá and Solimões) with contrasting topography. River terraces are also found along the main rivers in the area. Local topographic conditions were approximated by height above the nearest drainage (HAND), slope, and Strahler´s drainage order, all obtained from a SRTM digital elevation model...
Silica is the best-known component filling the spaces that form phytoliths in many plants, but ph... more Silica is the best-known component filling the spaces that form phytoliths in many plants, but phytoliths may also contain other elements. We used scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX) to map element distributions in the leaves of Guadua bamboo, which is a successful competitor in southwestern Amazonian forests. We emphasize immobile elements that can be mineralized (silicon and calcium) as well as potassium, an abundant mobile nutrient with many vital functions. We discovered high silicon (Si) content with little or no calcium (Ca) or potassium (K) in bulliform cells, bilobate shaped short cells and stomata, all of which can form phytoliths, and moderately high Si content in the bundle sheet, prickle tips and papillae. K often surrounded Si-loaded cells, Si and K had overlapping distributions in the intercostal areas near vein margins, and Ca showed abundant spotted distribution in the intercostal areas. The dark inside content of the cost...
Forest structure determines light availability for understorey plants. The structure of lowland A... more Forest structure determines light availability for understorey plants. The structure of lowland Amazonian forests is known to vary over long edaphic gradients, but whether more subtle edaphic variation also affects forest structure has not beenresolved. In western Amazonia, the majority of non-flooded forests grow on soils derived either from relatively fertile sediments of the Pebas Formation or from poorer sediments of the Nauta Formation. The objective of this study was to compare structure and light availability in the understorey of forests growing on these two geological formations. We measured canopy openness and tree stem densities in three size classes in northeastern Peru in a total of 275 study points in old-growth terra firme forests representing the two geological formations. We also documented variation in floristic composition (ferns, lycophytes and the palm Iriartea deltoidea) and used Landsat TM satellite image information to model the forest structural and floristi...
Les modèles de distribution des plantes de la forêt pluvieuse de l'Amazonie sont peu connus à... more Les modèles de distribution des plantes de la forêt pluvieuse de l'Amazonie sont peu connus à cause d'une recherche botanique inadéquate et géographiquement inégale. Si les espèces végétales forment de manière récurrente des communautés écologiquement restreintes, il devrait y avoir des modèles de distribution récurrents qui pourraient être découverts en étudiant seulement une partie de la flore. Les comparaisons de la flore de douze terrains d'étude différents dans l'Amazonie péruvienne sur la base d'arbres supérieurs à 2,5 cm de diamètre à la hauteur de la poitrine, fougères terrestres et #Melastomataceae$, indiquent qu'il existe des communautés de plantes récurrentes et que les fougères et #Melastomataceae$ sont de très bons indicateurs de plusieurs modèles phytogéographiques généraux en Amazonie. (Résumé d'auteur)
Data on the Amazonian Malaise trapping carried out in 1998, 2000, 2008 and 2011 by the University... more Data on the Amazonian Malaise trapping carried out in 1998, 2000, 2008 and 2011 by the University of Turku. Flying insects were collected by Malaise traps in Peruvian Amazonia by Ilari Sääksjärvi and Isrrael Gómez. The dataset contains data on what samples were collected, on the trap sites, on the vegetation around the trap sites, and on the weather. More importantly, it contains information on how this data was compiled. There was no complete list of Amazonian Malaise samples before this, and the sample data had to be combined from multiple sources. This dataset is also described in the associated paper (link to come when published).
Species and soil data were collected in the field by the researchers mentioned as data providers ... more Species and soil data were collected in the field by the researchers mentioned as data providers for each plot. Reflectance data come from a Landsat TM/ETM+ image composite based on images acquired in 2000-2009 and processed using R code written by Jasper Van doninck. CHELSA and SRTM data come from respective online portals. See README file for explanation of the data contained in each column
Datasets of the dialect group analyses. Linguistic FST distances (sheet 1), geographical distance... more Datasets of the dialect group analyses. Linguistic FST distances (sheet 1), geographical distances (sheet 2) and raw data of 33 environmental and cultural variables (sheet 3) used in the analyses of the dialect groups. (XLS 52 kb)
Linguistic distances between municipalities. Rough equivalents of Séguy's dialect distance me... more Linguistic distances between municipalities. Rough equivalents of Séguy's dialect distance metric, i.e. a percentage of disagreeing linguistic features between pairs of municipal dialects. (CSV 1277 kb)
Aim: To map and interpret floristic and geoecological patterns across the Amazon basin by combini... more Aim: To map and interpret floristic and geoecological patterns across the Amazon basin by combining extensive field data with basin-wide Landsat imagery and climatic data Location: Amazonia Taxon: Ground truth data on ferns and lycophytes; remote sensing results reflect forest canopy properties Methods: We used field plot data to assess main ecological gradients across Amazonia and to relate floristic ordination axes to soil base cation concentration, CHELSA climatic variables and reflectance values from a basin-wide Landsat image composite with generalized linear models (GLM). Ordination axes were then predicted across all Amazonia using Landsat and CHELSA, and a regional subdivision was obtained using k-medoid classification. Results: The primary floristic gradient was strongly related to base cation concentration in the soil, and the secondary gradient to climatic variables. The Landsat image composite revealed a tapestry of broad-scale variation in canopy reflectance characteristics across Amazonia. Ordination axis scores predicted using Landsat and CHELSA variables produced spatial patterns consistent with existing knowledge on soils, geology and vegetation, but also suggested new floristic patterns. The clearest dichotomy was between central Amazonia and the peripheral areas, and the available data supported a classification into at least eight subregions. Main conclusions Landsat data are capable of predicting soil-related species compositional patterns of understory ferns and lycophytes across the Amazon basin with surprisingly high accuracy. Although the exact floristic relationships may differ among plant groups, the observed ecological gradients must be relevant for other plants as well, since surface reflectance recorded by satellites is mostly influenced by the tree canopy. This opens exciting prospects for species distribution modelling, conservation planning, and biogeographical and ecological studies on Amazonian biota. Our maps provide a preliminary geoecological subdivision of Amazonia that can now be tested and refined using field data of other plant groups and from hitherto unsampled areas
:Two core questions in plant community ecology are to what extent the distributions of species ar... more :Two core questions in plant community ecology are to what extent the distributions of species are structured by local environmental conditions, and whether taxa differ in this regard. We compared the distributions of trees, Melastomataceae and ferns on soil and topographic gradients in a Costa Rican lowland rain forest (trees and ferns 983 plots, Melastomataceae 277 plots). To test whether these plant groups differed in the prevalence or type of habitat specialization, we calculated species’ environmental optima and tolerances on each gradient. Habitat specialization was defined as a significantly biased optimum, or a narrow tolerance, relative to values obtained under spatially restricted randomizations of species occurrences. Within plant groups, we also asked whether the dispersion of species optima differed from random expectation on each gradient. Fern optima were over-dispersed on multiple gradients, implying considerable interspecific habitat partitioning, and tree optima were over-dispersed in relation to topographic position. Habitat specialization was more prevalent in the two predominantly understorey groups than in trees (75% of Melastomataceae species, 81–87% of ferns, 57–58% of trees). Species optima of Melastomataceae and ferns also tended towards lower landscape positions than did those of trees, perhaps reflecting a higher proportion of drought-sensitive species in these two groups.
We examine the Indigenous uses, oral histories, and knowledge of native Guadua bamboo species in ... more We examine the Indigenous uses, oral histories, and knowledge of native Guadua bamboo species in southwestern Amazonia. Two Guadua species form dense stands in which individual plants die en masse at regular intervals of about 28 years. Scholars suggested that pre-colonial earth builders took advantage of these die-off events as a natural aid in removing the forest to construct geometric earthworks. Our results show that Guadua species have a significant position in Indigenous socio-cosmologies, land use, and as a protector of diverse resources. Indigenous ontological understandings cannot be separated from discussions of the abundance and geographical distribution of Guadua as a critical controlling factor in the vegetation structure and function of southwestern Amazonian rain forests. Furthermore, oral histories point to the connection between land management and bamboo, as well as bamboo and the use of fire, conforming to the suggestion of opening ceremonial spaces in bamboo patches in pre-colonial earthwork societies.
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