I am a devoted researcher of the plant systematics and I love tropical grasslands and forests Phone: 52+9999423200 Address: Carr. Merida Xmatkuil km 15.5, Merida, Yucatan Mexico
Temporarily flooded forests (TFF’s) are among the most endangered tree communities in Southeast M... more Temporarily flooded forests (TFF’s) are among the most endangered tree communities in Southeast Mexico and in a contradictory way among the least known in terms of their diversity. Therefore, the aim of this study was to characterize the richness, diversity (Shannon-Wiener) and dominance (relative importance value; RIV) of a TFF of the Yucatan Peninsula, and evaluate its floristic affinities with other TFF’s and upland forests (UF’s) of Southeast Mexico. A sampling method based on 10 quadrants of 10 x 20 m (2 000 m2) was used to record all woody individuals with diameter ≥ 1 cm and height ≥ 1.5 m. A floristic similarity analysis was used including 192 genera of woody plants belonging to TFF’s and UF’s of the Yucatan and Tabasco TFF’s. A Mantel correlation test was performed to determine if the geographic distance has effect on the floristic similarities between TFF’s and UF´s of the Yucatan peninsula. The TFF under study was characterized with a low level of diversity (2.79) and spe...
Environmental heterogeneity of Belize and southern Mexico savannahs as well as their geographical... more Environmental heterogeneity of Belize and southern Mexico savannahs as well as their geographical location suggest that these plant communities share floristic elements, making them conducive to a phytogeographical analysis. The aim of this study was to analyse the floristic affinities of nine savannahs of Belize and southern Mexico and to explain the similarities and differences amongst them. A binary data matrix containing 915 species was built based on the authors' own collections and on nine floristic lists already published. A second data matrix, consisting of 113 species representing trees, was also used since most literature on neotropical savannahs has focused on this life form. In addition, the ten most species-rich families as well as the characteristic species present in more than five savannahs were analysed. Floristic similarities were calculated using the Jaccard index. Dendrograms obtained in both types of analysis showed clusters with low similarity values, corre...
... We are grate-ful to many people for their assistance with field work. Particularly, J. Tun, E... more ... We are grate-ful to many people for their assistance with field work. Particularly, J. Tun, E. Ucdn, LM Ortega, S. Avendano, Y. Herrera, S. Gonzalez and E. Estrada. ... 393-458. Bor, N. L (I960).'Grasses of India, Burma and Ceylon'.(Pergamon: Oxford.) Clayton, WD (1964). ...
The traditional Mayan house is one of the most efficient buildings in space and adapta - tion to ... more The traditional Mayan house is one of the most efficient buildings in space and adapta - tion to local climatic conditions. The most commonly used local trad...
A taxonomic treatment of Sporobolus R. Br. for northeastern Mexico (Coahuifa, Nuevo Leon, and Tam... more A taxonomic treatment of Sporobolus R. Br. for northeastern Mexico (Coahuifa, Nuevo Leon, and Tamaulipas), is given. Seventeen species and one subspecies of Sporobolus are recognized in the study area. Sporobolus airoides subsp. regis is endemic to Coahuifa, and S. atrovirens and S. spicijormis are endemic to Mexico. Keys for determining the species, descriptions, distributions, specimens exam-ined, iifustrations, synonymies, and a brief discussion indicating relationships among alf native and adventive species of Sporobolus in northeastern Mexico are provided. RESUMEN
Background: Coastal ecosystems in Mexico remain understudied in spite of their ecological, econom... more Background: Coastal ecosystems in Mexico remain understudied in spite of their ecological, economic and conservation value and are being impacted by human activities along the coast. Knowledge on spatial patterns of plant species distribution that helps preserve these fragile ecosystems is crucial. Aims: We evaluated differences in species richness, species diversity and species dominance patterns in 16 plant communities as well as the degree to which differences were driven by climatic conditions in sandy dunes in Yucatán. We evaluated the importance of invasive species in mediating patterns of species diversity and species dominance patterns. Results: We found wide variation in plant species richness, species diversity and species dominance patterns among communities that stems from broad climatic differences along dune systems. Invasive plants represent almost one-third of total species richness and seem to be drastically changing the species dominance patterns in these communities. Conclusions: Regional climatic differences along the Yucatán north coast seems to be a major driver of plant diversity and species composition. Our findings suggest that invasive plants have successfully colonised and spread along the coast over the past 30 years. Even though invasive species do not alter spatial patterns of species diversity, they are becoming more dominant with potential detrimental consequences for native plants.
Coccoloba floresii is here described as a new species from Mexico. Morphological characters of th... more Coccoloba floresii is here described as a new species from Mexico. Morphological characters of the leaf, inflorescence, and fruit show discontinuities among populations of C. floresii and its relatives, C. barbadensis and C. cozumelensis. In addition, C. floresii is exclusive of the tropical dry forests of Central Depression and Plateau of Chiapas (Mexico) at high elevations.
Page 1. Allelic variation in the amphitropical disjunct Muhlenbergia torreyi (Poaceae: Muhlenberg... more Page 1. Allelic variation in the amphitropical disjunct Muhlenbergia torreyi (Poaceae: Muhlenbergiinae) PAUL Mo PETERSON AND JUAN JAVIER ORTLZ-DIAZ Peterson, PM (Dept. of Botany, NHB-166, National Museum of ...
n the Yucatan peninsula, savannas are distributed as small enclaves clearly delimited bybtropical... more n the Yucatan peninsula, savannas are distributed as small enclaves clearly delimited bybtropical forest tree. Savanna fl ora is of a great botanical interest, because it is determined by soil conditions. The aim of this study was to identify and describe the fl ora and ways of life of two sheets in Xmaben, Campeche. As a result 127 species belonging to 97 genera and 41 families were recorded. Poaceae, Fabaceae, Cyperaceae, Malvaceae and Convolvulaceae had the largest number of genera and species. The richest genera were Paspalum (six), Cyperus (five), Eleocharis (four), Echinodorus, Ipomoea, Mimosa and Panicum (three each). The herbaceous plant life form was the best represented with 94 species (74.01%). The Jaccard similarity index was 0.157, since the two savannas share only 19 species out of 127. The absence of introduced plants in the sites is a strong indicator of its natural origin.
A systematic treatment of the genus Gouinia is presented. Geographical distribution, morphology,... more A systematic treatment of the genus Gouinia is presented. Geographical distribution, morphology, leaf anatomy, photosynthetic pathways and chromosome numbers are analyzed. Twelve taxa of Gouinia including 9 species and 6 varieties are recognized. One species, one variety and one combination are new. Synonymy, descriptions, ecological data, discussions, common names lists of herbarium speciemens are given for each species.
Schenckochloa (Poaceae, Chloridoideae, Eragrostideae), un género nuevo del Noreste de Brasil. ORT... more Schenckochloa (Poaceae, Chloridoideae, Eragrostideae), un género nuevo del Noreste de Brasil. ORTÍZ, J. J. (1991). Schenckochloa (Poaceae, Chloridoideae, Eragrostideae), genre nouveau du nord-est du Brésil. Candollea 46: 241-249. En espagnol, résumés franqais et anglais. Ijauteur décrit un genre nouveau: Schenckochloa du nord-est du Brésil. S. barbata a des caractéristiques morphologiques et anatomiques trés particuliéres qui la différencient des autres especies du genre Gouinia ei des autres genres voisins dans la tribu des Eragrostideae. Une clef permettant de distinguer cette especie des autres taxons des genres voisins est présentée. ABSTRACT ORTÍZ, J. J. (1991). Schenckochloa (Poaceae, Chloridoideae, Eragrostideae), new genus from northeast of Brazil. Candollea 46:241-249. In Spanish, French and English abstracts. A new genus, Schenckochloa from northeast of Brazil. S. barbata has a set of morphological and anatomical characters, which separate this taxon from the other species of genus Gouinia and related genera. A key to the allied genera is presented.
Temporarily flooded forests (TFF’s) are among the most endangered tree communities in Southeast M... more Temporarily flooded forests (TFF’s) are among the most endangered tree communities in Southeast Mexico and in a contradictory way among the least known in terms of their diversity. Therefore, the aim of this study was to characterize the richness, diversity (Shannon-Wiener) and dominance (relative importance value; RIV) of a TFF of the Yucatan Peninsula, and evaluate its floristic affinities with other TFF’s and upland forests (UF’s) of Southeast Mexico. A sampling method based on 10 quadrants of 10 x 20 m (2 000 m2) was used to record all woody individuals with diameter ≥ 1 cm and height ≥ 1.5 m. A floristic similarity analysis was used including 192 genera of woody plants belonging to TFF’s and UF’s of the Yucatan and Tabasco TFF’s. A Mantel correlation test was performed to determine if the geographic distance has effect on the floristic similarities between TFF’s and UF´s of the Yucatan peninsula. The TFF under study was characterized with a low level of diversity (2.79) and spe...
Environmental heterogeneity of Belize and southern Mexico savannahs as well as their geographical... more Environmental heterogeneity of Belize and southern Mexico savannahs as well as their geographical location suggest that these plant communities share floristic elements, making them conducive to a phytogeographical analysis. The aim of this study was to analyse the floristic affinities of nine savannahs of Belize and southern Mexico and to explain the similarities and differences amongst them. A binary data matrix containing 915 species was built based on the authors' own collections and on nine floristic lists already published. A second data matrix, consisting of 113 species representing trees, was also used since most literature on neotropical savannahs has focused on this life form. In addition, the ten most species-rich families as well as the characteristic species present in more than five savannahs were analysed. Floristic similarities were calculated using the Jaccard index. Dendrograms obtained in both types of analysis showed clusters with low similarity values, corre...
... We are grate-ful to many people for their assistance with field work. Particularly, J. Tun, E... more ... We are grate-ful to many people for their assistance with field work. Particularly, J. Tun, E. Ucdn, LM Ortega, S. Avendano, Y. Herrera, S. Gonzalez and E. Estrada. ... 393-458. Bor, N. L (I960).'Grasses of India, Burma and Ceylon'.(Pergamon: Oxford.) Clayton, WD (1964). ...
The traditional Mayan house is one of the most efficient buildings in space and adapta - tion to ... more The traditional Mayan house is one of the most efficient buildings in space and adapta - tion to local climatic conditions. The most commonly used local trad...
A taxonomic treatment of Sporobolus R. Br. for northeastern Mexico (Coahuifa, Nuevo Leon, and Tam... more A taxonomic treatment of Sporobolus R. Br. for northeastern Mexico (Coahuifa, Nuevo Leon, and Tamaulipas), is given. Seventeen species and one subspecies of Sporobolus are recognized in the study area. Sporobolus airoides subsp. regis is endemic to Coahuifa, and S. atrovirens and S. spicijormis are endemic to Mexico. Keys for determining the species, descriptions, distributions, specimens exam-ined, iifustrations, synonymies, and a brief discussion indicating relationships among alf native and adventive species of Sporobolus in northeastern Mexico are provided. RESUMEN
Background: Coastal ecosystems in Mexico remain understudied in spite of their ecological, econom... more Background: Coastal ecosystems in Mexico remain understudied in spite of their ecological, economic and conservation value and are being impacted by human activities along the coast. Knowledge on spatial patterns of plant species distribution that helps preserve these fragile ecosystems is crucial. Aims: We evaluated differences in species richness, species diversity and species dominance patterns in 16 plant communities as well as the degree to which differences were driven by climatic conditions in sandy dunes in Yucatán. We evaluated the importance of invasive species in mediating patterns of species diversity and species dominance patterns. Results: We found wide variation in plant species richness, species diversity and species dominance patterns among communities that stems from broad climatic differences along dune systems. Invasive plants represent almost one-third of total species richness and seem to be drastically changing the species dominance patterns in these communities. Conclusions: Regional climatic differences along the Yucatán north coast seems to be a major driver of plant diversity and species composition. Our findings suggest that invasive plants have successfully colonised and spread along the coast over the past 30 years. Even though invasive species do not alter spatial patterns of species diversity, they are becoming more dominant with potential detrimental consequences for native plants.
Coccoloba floresii is here described as a new species from Mexico. Morphological characters of th... more Coccoloba floresii is here described as a new species from Mexico. Morphological characters of the leaf, inflorescence, and fruit show discontinuities among populations of C. floresii and its relatives, C. barbadensis and C. cozumelensis. In addition, C. floresii is exclusive of the tropical dry forests of Central Depression and Plateau of Chiapas (Mexico) at high elevations.
Page 1. Allelic variation in the amphitropical disjunct Muhlenbergia torreyi (Poaceae: Muhlenberg... more Page 1. Allelic variation in the amphitropical disjunct Muhlenbergia torreyi (Poaceae: Muhlenbergiinae) PAUL Mo PETERSON AND JUAN JAVIER ORTLZ-DIAZ Peterson, PM (Dept. of Botany, NHB-166, National Museum of ...
n the Yucatan peninsula, savannas are distributed as small enclaves clearly delimited bybtropical... more n the Yucatan peninsula, savannas are distributed as small enclaves clearly delimited bybtropical forest tree. Savanna fl ora is of a great botanical interest, because it is determined by soil conditions. The aim of this study was to identify and describe the fl ora and ways of life of two sheets in Xmaben, Campeche. As a result 127 species belonging to 97 genera and 41 families were recorded. Poaceae, Fabaceae, Cyperaceae, Malvaceae and Convolvulaceae had the largest number of genera and species. The richest genera were Paspalum (six), Cyperus (five), Eleocharis (four), Echinodorus, Ipomoea, Mimosa and Panicum (three each). The herbaceous plant life form was the best represented with 94 species (74.01%). The Jaccard similarity index was 0.157, since the two savannas share only 19 species out of 127. The absence of introduced plants in the sites is a strong indicator of its natural origin.
A systematic treatment of the genus Gouinia is presented. Geographical distribution, morphology,... more A systematic treatment of the genus Gouinia is presented. Geographical distribution, morphology, leaf anatomy, photosynthetic pathways and chromosome numbers are analyzed. Twelve taxa of Gouinia including 9 species and 6 varieties are recognized. One species, one variety and one combination are new. Synonymy, descriptions, ecological data, discussions, common names lists of herbarium speciemens are given for each species.
Schenckochloa (Poaceae, Chloridoideae, Eragrostideae), un género nuevo del Noreste de Brasil. ORT... more Schenckochloa (Poaceae, Chloridoideae, Eragrostideae), un género nuevo del Noreste de Brasil. ORTÍZ, J. J. (1991). Schenckochloa (Poaceae, Chloridoideae, Eragrostideae), genre nouveau du nord-est du Brésil. Candollea 46: 241-249. En espagnol, résumés franqais et anglais. Ijauteur décrit un genre nouveau: Schenckochloa du nord-est du Brésil. S. barbata a des caractéristiques morphologiques et anatomiques trés particuliéres qui la différencient des autres especies du genre Gouinia ei des autres genres voisins dans la tribu des Eragrostideae. Une clef permettant de distinguer cette especie des autres taxons des genres voisins est présentée. ABSTRACT ORTÍZ, J. J. (1991). Schenckochloa (Poaceae, Chloridoideae, Eragrostideae), new genus from northeast of Brazil. Candollea 46:241-249. In Spanish, French and English abstracts. A new genus, Schenckochloa from northeast of Brazil. S. barbata has a set of morphological and anatomical characters, which separate this taxon from the other species of genus Gouinia and related genera. A key to the allied genera is presented.
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Papers by Juan Javier Ortiz Diaz
botanical interest, because it is determined by soil conditions. The aim of this study was to identify and describe the fl ora and ways of
life of two sheets in Xmaben, Campeche. As a result 127 species belonging to 97 genera and 41 families were recorded. Poaceae, Fabaceae, Cyperaceae, Malvaceae and Convolvulaceae had the largest number of genera and species. The richest genera were Paspalum (six), Cyperus (five), Eleocharis (four), Echinodorus,
Ipomoea, Mimosa and Panicum (three each). The herbaceous plant life form was the best represented with 94 species (74.01%). The
Jaccard similarity index was 0.157, since the two savannas share only 19 species out of 127. The absence of introduced plants in the sites is a strong indicator of its natural origin.
botanical interest, because it is determined by soil conditions. The aim of this study was to identify and describe the fl ora and ways of
life of two sheets in Xmaben, Campeche. As a result 127 species belonging to 97 genera and 41 families were recorded. Poaceae, Fabaceae, Cyperaceae, Malvaceae and Convolvulaceae had the largest number of genera and species. The richest genera were Paspalum (six), Cyperus (five), Eleocharis (four), Echinodorus,
Ipomoea, Mimosa and Panicum (three each). The herbaceous plant life form was the best represented with 94 species (74.01%). The
Jaccard similarity index was 0.157, since the two savannas share only 19 species out of 127. The absence of introduced plants in the sites is a strong indicator of its natural origin.