AimTo investigate the geographic patterns and ecological correlates in the geographic distributio... more AimTo investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser‐availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource‐availability hypothesis).Time periodTree‐inventory plots established between 1934 and 2019.Major taxa studiedTrees with a diameter at breast height (DBH) ≥ 9.55 cm.LocationAmazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield.MethodsWe assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree‐inventory plots across terra‐firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We ...
In a time of rapid global change, the question of what determines patterns in species abundance d... more In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary ...
The aerial roots of Heteropsis flexuosa (Kunth) Bunting, a hemi-epiphyte, are harvested by indige... more The aerial roots of Heteropsis flexuosa (Kunth) Bunting, a hemi-epiphyte, are harvested by indigenous communities in Guyana for a developing wicker furniture market. Nibbi roots have potential as a sustainably harvested product, but there is little data to guide management. I examined nibbi biology, harvest response, product yield and use at several forest sites. H. flexuosa is a relatively abundant plant and 35% of trees (_> 10 cm dbh) in plots were hosts. Stems exhibited mean growth rates of 1-3 cm per month. Aerial roots grew a mean 156 cm per month and some reached maturity within 6 months. With present methods, harvest does not decimate populations because 97% of colonized trees possess few harvestable roots. But, only 28% of cut roots regenerated in experiments. For indigenous harvesters at Manawarin village, nibbi harvesting is a primary source of cash income and is important in daily subsistence. iv TABLE OF CONTENTS Acknowledgements Abstract Table of Contents List of Figures and Tables I. INTRODUCTION AND BACKGROUND 1 l. l T h e S t u d y P l a n t : H e t e r o p s i s F l e x u o s a (K u n t h) B u n t i n g 6 l .2 p h y s i c a l G e o g r a p h y 23 1.3 H u m a n G e o g r a p h y 33 II. N a t u r a l d i s t r i b u t i o n. G r o w t h a n d r o o t A n a t o m y o f n i b b i 2.1 INTRODUCTION 47 2 .2 MATERIALS AND METHODS 48 2.3 RESULTS AND DISCUSSION 58 2 .4 CONCLUSIONS 81 III. Im p a c t o f A e r ia l R o o t H a r v e s t o n N ib b i 3.1 In t r o d u c t i o n 83 3.2 M a t e r i a l s a n d M e t h o d s 83 3 .3 R e s u l t s a n d D i s c u s s i o n A. HARVEST INTENSITY 89 B. HARVEST IMPACT 90 3 .4 CONCLUSIONS 97 IV. ECONOMICS OF NIBBI
The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We per... more The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.
Introduction Recent decades have seen a major international effort to inventory tree communities ... more Introduction Recent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but the vast extent and record diversity of these forests have hampered an understanding of basinwide patterns. To overcome this obstacle, we compiled and standardized species-level data on more than half a million trees in 1170 plots sampling all major lowland forest types to explore patterns of commonness, rarity, and richness. Methods The ~6-million-km 2 Amazonian lowlands were divided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify sampling error, was used to generate estimated Amazon-wide abundances of the 4962 valid species in the data set. We estimated the total number of tree species in the Amazon by fitting t...
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics ... more Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such “monodominant” forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree specie...
The Amazon Basin is at the center of an intensifying discourse about deforestation, land-use, and... more The Amazon Basin is at the center of an intensifying discourse about deforestation, land-use, and global change. To date, climate research in the Basin has overwhelmingly focused on the cycling and storage of carbon (C) and its implications for global climate. Missing, however, is a more comprehensive consideration of other significant biophysical climate feedbacks [i.e., CH4, N2O, black carbon, biogenic volatile organic compounds (BVOCs), aerosols, evapotranspiration, and albedo] and their dynamic responses to both localized (fire, land-use change, infrastructure development, and storms) and global (warming, drying, and some related to El Niño or to warming in the tropical Atlantic) changes. Here, we synthesize the current understanding of (1) sources and fluxes of all major forcing agents, (2) the demonstrated or expected impact of global and local changes on each agent, and (3) the nature, extent, and drivers of anthropogenic change in the Basin. We highlight the large uncertaint...
The Amazon Basin is at the center of an intensifying discourse about deforestation, land-use, and... more The Amazon Basin is at the center of an intensifying discourse about deforestation, land-use, and global change. To date, climate research in the Basin has overwhelmingly focused on the cycling and storage of carbon (C) and its implications for global climate. Missing, however, is a more comprehensive consideration of other significant biophysical climate feedbacks [i.e., CH4, N2O, black carbon, biogenic volatile organic compounds (BVOCs), aerosols, evapotranspiration, and albedo] and their dynamic responses to both localized (fire, land-use change, infrastructure development, and storms) and global (warming, drying, and some related to El Niño or to warming in the tropical Atlantic) changes. Here, we synthesize the current understanding of (1) sources and fluxes of all major forcing agents, (2) the demonstrated or expected impact of global and local changes on each agent, and (3) the nature, extent, and drivers of anthropogenic change in the Basin. We highlight the large uncertaint...
Despite the increasing use of quantitative methods in ethnobotany, there has been relatively litt... more Despite the increasing use of quantitative methods in ethnobotany, there has been relatively little advance in understanding of cross-cultural patterns. Within three tropical forest vegetation zones, I documented and compared local plant knowledge, categorical use, and resource selection for a short-resident (±300 years) Afro-American Saramacca "Maroon" community and an indigenous Caribanspeaking Trio community. For 3-4 male specialists at each site, the "recognition" and use of stems ³ 10 cm dbh in forest plots (0.5-1 ha) was recorded. Comparative methods included quantitative use value indices and categorized uses (construction, edible, medicine, technology, and trade). The Trio emphasized medicinal uses regardless of vegetation zone. Saramacca use value was greatest within fallow forest, exceeded Trio knowledge for "construction" and "trade," and emphasized timber and carving species. For both groups, the use value of most taxa (family and species) was correlated with "apparency" (abundance, species richness), with the exception of palms and major cultural species. As hypothesized, Trio indigenous knowledge was greater-with more biological species named (97.3% vs. 83.9%) and utilized (87.7% vs. 66.9%) and more uses cited per species. However, the shorter-resident Saramacca Maroon participants still revealed a robust knowledge and use of woody plant diversity.
To date, reasons for the increase in liana abundance and biomass in the Neotropics are still uncl... more To date, reasons for the increase in liana abundance and biomass in the Neotropics are still unclear. One proposed hypothesis suggests that lianas, in comparison with trees, are more adaptable to drought conditions. Moreover, previous studies have assumed that lianas have a deeper root system, which provides access to deeper soil layers, thereby making them less susceptible to drought stress. The dual stable water isotope approach (δ 18 O and δ 2 H) enables below-ground vegetation competition for water to be studied. Based on the occurrence of a natural gradient in soil water isotopic signatures, with enriched signatures in shallow soil relative to deep soil, the origin of vegetation water sources can be derived. Our study was performed on canopy trees and lianas reaching canopy level in tropical forests of French Guiana. Our results show liana xylem water isotopic signatures to be enriched in heavy isotopes in comparison with those from trees, indicating differences in water source depths and a more superficial root activity for lianas during the dry season. This enables them to efficiently capture dry season precipitation. Our study does not support the liana deep root water extraction hypothesis. Additionally, we provide new insights into water competition between tropical canopy lianas and trees. Results suggest that this competition is mitigated during the dry season due to water resource partitioning.
Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDM... more Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area of occupancy of the species. We found a significant but weak positive relationship between the distribution of NHCs and IDW for 66% of the species. The relationship between SDMs and IDW was also significant but weakly positive for 95% of the species, and sensitivity for both analyses was high. Furthermore, the pipeline removed half of the NHCs records. Presence-only SDM applications should consider th...
Species distribution models (SDMs) are widely used in the fields of macroecology, biogeography an... more Species distribution models (SDMs) are widely used in the fields of macroecology, biogeography and biodiversity research for modelling species geographic distributions based on correlations between known occurrence records and the environmental conditions at occurrence localities1,2. SDMs generate geographical maps of a species’ environmental suitability, its likelihood of being collected, and its local abundance3. Their application includes selecting conservation areas, predicting the effects of climate change on species ranges and determining the risk of species invasions. The wide use of SDMs in ecological and conservation research can partly be explained by the growing availability of georeferenced species records (e.g. GBIF, SpeciesLink) and environmental data (e.g. WorldClim, CliMond) on the web, together with the user-friendly character of some of the modelling methods. One of the most commonly used SDMs is MaxEnt, which has become increasingly popular since its introduction....
Measuring the "importance" of plants and vegetation to people is a central concern in quantitativ... more Measuring the "importance" of plants and vegetation to people is a central concern in quantitative ethnobotany. A common tool to quantify otherwise qualitative data in the biological and social sciences is an index. Relative cultural importance (RCI) indices such as the "use values" developed by Prance et al. (1987) and Phillips and Gentry (1993a, 1993b) are applied in ethnobotany to calculate a value per folk or biological plant taxon. These approaches can provide data amenable to hypothesis-testing, statistical validation, and comparative analysis. The use of RCI indices is a growing trend in ethnobotanical research, yet there have been few attempts to compile or standardize divergent methods. In this review, we compare RCI indices in four broad categories and present a step-by-step guide to some specific methods. Important background topics are addressed, including ethnographic methods, use categorization, sampling, and statistical analysis. We are concerned here only with "value" as a non-monetary concept. The aspiring and veteran researcher alike should find this paper a useful guide to the development and application of RCI indices.
Despite the increasing use of quantitative methods in ethnobotany, there has been relatively litt... more Despite the increasing use of quantitative methods in ethnobotany, there has been relatively little advance in understanding of cross-cultural patterns. Within three tropical forest vegetation zones, I documented and compared local plant knowledge, categorical use, and resource selection for a short-resident (±300 years) Afro-American Saramacca "Maroon" community and an indigenous Caribanspeaking Trio community. For 3-4 male specialists at each site, the "recognition" and use of stems ³ 10 cm dbh in forest plots (0.5-1 ha) was recorded. Comparative methods included quantitative use value indices and categorized uses (construction, edible, medicine, technology, and trade). The Trio emphasized medicinal uses regardless of vegetation zone. Saramacca use value was greatest within fallow forest, exceeded Trio knowledge for "construction" and "trade," and emphasized timber and carving species. For both groups, the use value of most taxa (family and species) was correlated with "apparency" (abundance, species richness), with the exception of palms and major cultural species. As hypothesized, Trio indigenous knowledge was greater-with more biological species named (97.3% vs. 83.9%) and utilized (87.7% vs. 66.9%) and more uses cited per species. However, the shorter-resident Saramacca Maroon participants still revealed a robust knowledge and use of woody plant diversity.
Measuring the " importance " of plants and vegetation to people is a central concern in... more Measuring the " importance " of plants and vegetation to people is a central concern in quantitative ethnobotany. A common tool to quantify otherwise qualitative data in the biological and social sciences is an index. Relative cultural importance (RCI) indices such as the " use values " developed by Prance et al. (1987) and Phillips and Gentry (1993a, 1993b) are applied in ethnobotany to calculate a value per folk or biological plant taxon. These approaches can provide data amenable to hypothesis-testing, statistical validation, and comparative analysis. The use of RCI indices is a growing trend in ethnobotanical research, yet there have been few attempts to compile or standardize divergent methods. In this review, we compare RCI indices in four broad categories and present a step-by-step guide to some specific methods. Important background topics are addressed, including ethnographic methods, use categorization, sampling, and statistical analysis. We are concern...
... Knab-Vispo, Claudia (Institute for Environmental Studies, University of Wisconsin-Madison, 55... more ... Knab-Vispo, Claudia (Institute for Environmental Studies, University of Wisconsin-Madison, 550 N. Park Street, Madison, WI 53706; current address: 1685 Route 5, Canaan, NY 12029), Bruce Hoffman (Department of Biological Sciences, Florida International ... nd), Rosales (pers. ...
... Knab-Vispo, Claudia (Institute for Environmental Studies, University of Wisconsin-Madison, 55... more ... Knab-Vispo, Claudia (Institute for Environmental Studies, University of Wisconsin-Madison, 550 N. Park Street, Madison, WI 53706; current address: 1685 Route 5, Canaan, NY 12029), Bruce Hoffman (Department of Biological Sciences, Florida International ... nd), Rosales (pers. ...
ABSTRACT The effect of the matrix within which habitat fragmentation occurs was studied with resp... more ABSTRACT The effect of the matrix within which habitat fragmentation occurs was studied with respect to gypsy moth (Lymantria dispar L.) egg-mass number on the E. S. George Reserve in Livingston Co., Michigan, in October 1999. Overgrown old fields were assumed to be relatively high quality matrix compared to a large herbaceous swamp. Oak forest fragments were located in each matrix type as well as in a reference matrix of extensive oak forest. The mean number of egg masses in stands of black oaks (Quercus velutina) was determined for fragments in high and low quality matrices. A significant difference in gypsy moth egg-mass number between areas of high vs. low quality matrix was detected.
AimTo investigate the geographic patterns and ecological correlates in the geographic distributio... more AimTo investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser‐availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource‐availability hypothesis).Time periodTree‐inventory plots established between 1934 and 2019.Major taxa studiedTrees with a diameter at breast height (DBH) ≥ 9.55 cm.LocationAmazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield.MethodsWe assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree‐inventory plots across terra‐firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We ...
In a time of rapid global change, the question of what determines patterns in species abundance d... more In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary ...
The aerial roots of Heteropsis flexuosa (Kunth) Bunting, a hemi-epiphyte, are harvested by indige... more The aerial roots of Heteropsis flexuosa (Kunth) Bunting, a hemi-epiphyte, are harvested by indigenous communities in Guyana for a developing wicker furniture market. Nibbi roots have potential as a sustainably harvested product, but there is little data to guide management. I examined nibbi biology, harvest response, product yield and use at several forest sites. H. flexuosa is a relatively abundant plant and 35% of trees (_> 10 cm dbh) in plots were hosts. Stems exhibited mean growth rates of 1-3 cm per month. Aerial roots grew a mean 156 cm per month and some reached maturity within 6 months. With present methods, harvest does not decimate populations because 97% of colonized trees possess few harvestable roots. But, only 28% of cut roots regenerated in experiments. For indigenous harvesters at Manawarin village, nibbi harvesting is a primary source of cash income and is important in daily subsistence. iv TABLE OF CONTENTS Acknowledgements Abstract Table of Contents List of Figures and Tables I. INTRODUCTION AND BACKGROUND 1 l. l T h e S t u d y P l a n t : H e t e r o p s i s F l e x u o s a (K u n t h) B u n t i n g 6 l .2 p h y s i c a l G e o g r a p h y 23 1.3 H u m a n G e o g r a p h y 33 II. N a t u r a l d i s t r i b u t i o n. G r o w t h a n d r o o t A n a t o m y o f n i b b i 2.1 INTRODUCTION 47 2 .2 MATERIALS AND METHODS 48 2.3 RESULTS AND DISCUSSION 58 2 .4 CONCLUSIONS 81 III. Im p a c t o f A e r ia l R o o t H a r v e s t o n N ib b i 3.1 In t r o d u c t i o n 83 3.2 M a t e r i a l s a n d M e t h o d s 83 3 .3 R e s u l t s a n d D i s c u s s i o n A. HARVEST INTENSITY 89 B. HARVEST IMPACT 90 3 .4 CONCLUSIONS 97 IV. ECONOMICS OF NIBBI
The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We per... more The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.
Introduction Recent decades have seen a major international effort to inventory tree communities ... more Introduction Recent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but the vast extent and record diversity of these forests have hampered an understanding of basinwide patterns. To overcome this obstacle, we compiled and standardized species-level data on more than half a million trees in 1170 plots sampling all major lowland forest types to explore patterns of commonness, rarity, and richness. Methods The ~6-million-km 2 Amazonian lowlands were divided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify sampling error, was used to generate estimated Amazon-wide abundances of the 4962 valid species in the data set. We estimated the total number of tree species in the Amazon by fitting t...
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics ... more Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such “monodominant” forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree specie...
The Amazon Basin is at the center of an intensifying discourse about deforestation, land-use, and... more The Amazon Basin is at the center of an intensifying discourse about deforestation, land-use, and global change. To date, climate research in the Basin has overwhelmingly focused on the cycling and storage of carbon (C) and its implications for global climate. Missing, however, is a more comprehensive consideration of other significant biophysical climate feedbacks [i.e., CH4, N2O, black carbon, biogenic volatile organic compounds (BVOCs), aerosols, evapotranspiration, and albedo] and their dynamic responses to both localized (fire, land-use change, infrastructure development, and storms) and global (warming, drying, and some related to El Niño or to warming in the tropical Atlantic) changes. Here, we synthesize the current understanding of (1) sources and fluxes of all major forcing agents, (2) the demonstrated or expected impact of global and local changes on each agent, and (3) the nature, extent, and drivers of anthropogenic change in the Basin. We highlight the large uncertaint...
The Amazon Basin is at the center of an intensifying discourse about deforestation, land-use, and... more The Amazon Basin is at the center of an intensifying discourse about deforestation, land-use, and global change. To date, climate research in the Basin has overwhelmingly focused on the cycling and storage of carbon (C) and its implications for global climate. Missing, however, is a more comprehensive consideration of other significant biophysical climate feedbacks [i.e., CH4, N2O, black carbon, biogenic volatile organic compounds (BVOCs), aerosols, evapotranspiration, and albedo] and their dynamic responses to both localized (fire, land-use change, infrastructure development, and storms) and global (warming, drying, and some related to El Niño or to warming in the tropical Atlantic) changes. Here, we synthesize the current understanding of (1) sources and fluxes of all major forcing agents, (2) the demonstrated or expected impact of global and local changes on each agent, and (3) the nature, extent, and drivers of anthropogenic change in the Basin. We highlight the large uncertaint...
Despite the increasing use of quantitative methods in ethnobotany, there has been relatively litt... more Despite the increasing use of quantitative methods in ethnobotany, there has been relatively little advance in understanding of cross-cultural patterns. Within three tropical forest vegetation zones, I documented and compared local plant knowledge, categorical use, and resource selection for a short-resident (±300 years) Afro-American Saramacca "Maroon" community and an indigenous Caribanspeaking Trio community. For 3-4 male specialists at each site, the "recognition" and use of stems ³ 10 cm dbh in forest plots (0.5-1 ha) was recorded. Comparative methods included quantitative use value indices and categorized uses (construction, edible, medicine, technology, and trade). The Trio emphasized medicinal uses regardless of vegetation zone. Saramacca use value was greatest within fallow forest, exceeded Trio knowledge for "construction" and "trade," and emphasized timber and carving species. For both groups, the use value of most taxa (family and species) was correlated with "apparency" (abundance, species richness), with the exception of palms and major cultural species. As hypothesized, Trio indigenous knowledge was greater-with more biological species named (97.3% vs. 83.9%) and utilized (87.7% vs. 66.9%) and more uses cited per species. However, the shorter-resident Saramacca Maroon participants still revealed a robust knowledge and use of woody plant diversity.
To date, reasons for the increase in liana abundance and biomass in the Neotropics are still uncl... more To date, reasons for the increase in liana abundance and biomass in the Neotropics are still unclear. One proposed hypothesis suggests that lianas, in comparison with trees, are more adaptable to drought conditions. Moreover, previous studies have assumed that lianas have a deeper root system, which provides access to deeper soil layers, thereby making them less susceptible to drought stress. The dual stable water isotope approach (δ 18 O and δ 2 H) enables below-ground vegetation competition for water to be studied. Based on the occurrence of a natural gradient in soil water isotopic signatures, with enriched signatures in shallow soil relative to deep soil, the origin of vegetation water sources can be derived. Our study was performed on canopy trees and lianas reaching canopy level in tropical forests of French Guiana. Our results show liana xylem water isotopic signatures to be enriched in heavy isotopes in comparison with those from trees, indicating differences in water source depths and a more superficial root activity for lianas during the dry season. This enables them to efficiently capture dry season precipitation. Our study does not support the liana deep root water extraction hypothesis. Additionally, we provide new insights into water competition between tropical canopy lianas and trees. Results suggest that this competition is mitigated during the dry season due to water resource partitioning.
Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDM... more Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area of occupancy of the species. We found a significant but weak positive relationship between the distribution of NHCs and IDW for 66% of the species. The relationship between SDMs and IDW was also significant but weakly positive for 95% of the species, and sensitivity for both analyses was high. Furthermore, the pipeline removed half of the NHCs records. Presence-only SDM applications should consider th...
Species distribution models (SDMs) are widely used in the fields of macroecology, biogeography an... more Species distribution models (SDMs) are widely used in the fields of macroecology, biogeography and biodiversity research for modelling species geographic distributions based on correlations between known occurrence records and the environmental conditions at occurrence localities1,2. SDMs generate geographical maps of a species’ environmental suitability, its likelihood of being collected, and its local abundance3. Their application includes selecting conservation areas, predicting the effects of climate change on species ranges and determining the risk of species invasions. The wide use of SDMs in ecological and conservation research can partly be explained by the growing availability of georeferenced species records (e.g. GBIF, SpeciesLink) and environmental data (e.g. WorldClim, CliMond) on the web, together with the user-friendly character of some of the modelling methods. One of the most commonly used SDMs is MaxEnt, which has become increasingly popular since its introduction....
Measuring the "importance" of plants and vegetation to people is a central concern in quantitativ... more Measuring the "importance" of plants and vegetation to people is a central concern in quantitative ethnobotany. A common tool to quantify otherwise qualitative data in the biological and social sciences is an index. Relative cultural importance (RCI) indices such as the "use values" developed by Prance et al. (1987) and Phillips and Gentry (1993a, 1993b) are applied in ethnobotany to calculate a value per folk or biological plant taxon. These approaches can provide data amenable to hypothesis-testing, statistical validation, and comparative analysis. The use of RCI indices is a growing trend in ethnobotanical research, yet there have been few attempts to compile or standardize divergent methods. In this review, we compare RCI indices in four broad categories and present a step-by-step guide to some specific methods. Important background topics are addressed, including ethnographic methods, use categorization, sampling, and statistical analysis. We are concerned here only with "value" as a non-monetary concept. The aspiring and veteran researcher alike should find this paper a useful guide to the development and application of RCI indices.
Despite the increasing use of quantitative methods in ethnobotany, there has been relatively litt... more Despite the increasing use of quantitative methods in ethnobotany, there has been relatively little advance in understanding of cross-cultural patterns. Within three tropical forest vegetation zones, I documented and compared local plant knowledge, categorical use, and resource selection for a short-resident (±300 years) Afro-American Saramacca "Maroon" community and an indigenous Caribanspeaking Trio community. For 3-4 male specialists at each site, the "recognition" and use of stems ³ 10 cm dbh in forest plots (0.5-1 ha) was recorded. Comparative methods included quantitative use value indices and categorized uses (construction, edible, medicine, technology, and trade). The Trio emphasized medicinal uses regardless of vegetation zone. Saramacca use value was greatest within fallow forest, exceeded Trio knowledge for "construction" and "trade," and emphasized timber and carving species. For both groups, the use value of most taxa (family and species) was correlated with "apparency" (abundance, species richness), with the exception of palms and major cultural species. As hypothesized, Trio indigenous knowledge was greater-with more biological species named (97.3% vs. 83.9%) and utilized (87.7% vs. 66.9%) and more uses cited per species. However, the shorter-resident Saramacca Maroon participants still revealed a robust knowledge and use of woody plant diversity.
Measuring the " importance " of plants and vegetation to people is a central concern in... more Measuring the " importance " of plants and vegetation to people is a central concern in quantitative ethnobotany. A common tool to quantify otherwise qualitative data in the biological and social sciences is an index. Relative cultural importance (RCI) indices such as the " use values " developed by Prance et al. (1987) and Phillips and Gentry (1993a, 1993b) are applied in ethnobotany to calculate a value per folk or biological plant taxon. These approaches can provide data amenable to hypothesis-testing, statistical validation, and comparative analysis. The use of RCI indices is a growing trend in ethnobotanical research, yet there have been few attempts to compile or standardize divergent methods. In this review, we compare RCI indices in four broad categories and present a step-by-step guide to some specific methods. Important background topics are addressed, including ethnographic methods, use categorization, sampling, and statistical analysis. We are concern...
... Knab-Vispo, Claudia (Institute for Environmental Studies, University of Wisconsin-Madison, 55... more ... Knab-Vispo, Claudia (Institute for Environmental Studies, University of Wisconsin-Madison, 550 N. Park Street, Madison, WI 53706; current address: 1685 Route 5, Canaan, NY 12029), Bruce Hoffman (Department of Biological Sciences, Florida International ... nd), Rosales (pers. ...
... Knab-Vispo, Claudia (Institute for Environmental Studies, University of Wisconsin-Madison, 55... more ... Knab-Vispo, Claudia (Institute for Environmental Studies, University of Wisconsin-Madison, 550 N. Park Street, Madison, WI 53706; current address: 1685 Route 5, Canaan, NY 12029), Bruce Hoffman (Department of Biological Sciences, Florida International ... nd), Rosales (pers. ...
ABSTRACT The effect of the matrix within which habitat fragmentation occurs was studied with resp... more ABSTRACT The effect of the matrix within which habitat fragmentation occurs was studied with respect to gypsy moth (Lymantria dispar L.) egg-mass number on the E. S. George Reserve in Livingston Co., Michigan, in October 1999. Overgrown old fields were assumed to be relatively high quality matrix compared to a large herbaceous swamp. Oak forest fragments were located in each matrix type as well as in a reference matrix of extensive oak forest. The mean number of egg masses in stands of black oaks (Quercus velutina) was determined for fragments in high and low quality matrices. A significant difference in gypsy moth egg-mass number between areas of high vs. low quality matrix was detected.
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Papers by Bruce Hoffman