Aim To analyse the distributional patterns of the Baja California Peninsula's resident avifauna, and to generate a regionalization based on a method that uses a parsimony analysis (parsimony analysis of endemicity, PAE) of point data and modelled potential distributions.Location The Baja California Peninsula, Mexico.Methods A data base was constructed containing records of 113 species of resident terrestrial birds present in the Baja California Peninsula. Records and localities were obtained from the literature and from specimens housed in scientific collections worldwide. Raw data points and potential distribution maps obtained using the software Genetic Algorithms for Rule-set Prediction (GARP), were analysed with PAE. ResultsThe data base consisted of 4164 unique records (only one combination of species/locality) belonging to 113 terrestrial resident bird species, in a total of 809 localities. From the point distribution matrix, the analysis generated 500 equally parsimonious trees, from which a strict consensus cladogram with 967 steps was obtained. The cladogram shows a basal polytomy and some geographical correspondence of a few resolved groups obtained in the analysis. These results do not allow the recognition of areas defined by avifaunistic associations. From the potential distribution matrix, the analysis generated 501 equally parsimonious trees, and a strict consensus cladogram of 516 steps was obtained. The cladogram shows a higher resolution because of the number of resolved groups with better geographical correspondence and therefore regions are well-defined.Main conclusions The correspondence of some groupings of species suggest their validity as areas with biogeographical (historical and/or ecological) meaning. This regionalization in the Baja California avifauna seems to be consistent with previous regionalizations for other groups. Hence, PAE is a useful tool for area categorization if reliable point records and prediction tools are available. Our results suggest that the geographical definition is much better using potential data generated by GARP, particularly when they are contrasted with the results from point data. Thus, this is an excellent alternative for developing biogeographical studies, as well as for improving the use of data from scientific collections and other sources of biodiversity information.

Aims We aimed to evaluate how climatic fluctuations influence the plasticity of anatomical vessel traits and the width of annual tree-rings of two relict-endemic Mexican Magnolia species. Notwithstanding, few studies have assessed the drought effect on vessel traits in tropical montane cloud trees of eastern Mexico. Methods Through digital images of growth rings, we assessed the tree radial growth rate, age of the trees and plasticity in vessel traits regarding climatic fluctuations of the Mexican Magnolia species studied. We compared vessel density, hydraulic diameter and percentage of conductive area in drought years (DY) and non-drought years (NDY) in two Mexican Magnolia species. Important Findings For the first time, the plasticity that occurs in porous wood vessel traits to long-term climatic fluctuations was analysed for two endangered Magnolia species (Magnolia vovidesii and M. schiedeana) from two tropical montane cloud forests in Mexico. We found that temperature and precipitation were strongly associated with differences in tree-ring width when DY and NDY were compared. Our analyses revealed that a high plasticity in vessel anatomy of diffuse-porous wood was related to temperature and/or water availability for both Magnolia species studied. We concluded that anatomical adaptations to DY resulted in a substantial reduction in vessel traits when compared with NDY, and that the plastic adaptations played an essential role in water transport and safety for the survival of the studied species during stressful long periods.

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Variation in leaf morphology is correlated with environmental variables, such as precipitation, temperature and soil composition. Several studies have pointed out that individual plasticity can largely explain the foliar phenotypic differences observed in populations due to climatic change and have suggested that the environment plays an important role in the evolution of plant species by selecting for phenotypic variation. Thus, the study of foliar morphology in plant populations can help us identify the environmental factors that have potentially influenced the process of species diversification. In this study, we analyzed morphological variation in the leaf traits of the Ternstroemia lineata species complex (Penthaphylacaceae) and its relation to climatic variables across the species distribution area to identify the patterns of morphological differentiation within this species complex. Based on the collected leaves of 270 individuals from 32 populations, we analyzed nine foliar traits using spatial interpolation models and multivariate statistics. A principal component analysis identified three main morphological traits (leaf length and two leaf shape variables) that were used to generate interpolated surface maps to detect discrete areas delimited by zones of rapid change in the values of the morphological traits. We identified a mosaic coarse-grain pattern of geographical distribution in the variation of foliar traits. According to the interpolation maps, we could define nine morphological groups and their geographic distributions. Longer leaves, spatulate leaves and the largest foliar area were located in sites with lower precipitation and higher seasonality of precipitation following a northwest–southeast direction and following significant latitudinal and longitudinal gradients. According to the phenogram of the relationships of the nine morphological groups based on morphological similarity, the putative species and subspecies of the T. lineata species complex did not show a clear pattern of differentiation. In this study, we found a complex pattern of differentiation with some isolated populations and some other contiguous populations differentiated by different traits. Further genetic and systematic studies are needed to clarify the evolutionary relationships in this species complex.

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He rba ri o FCME, Departamento de Bio logía, Facultad de Ciencias, Univ ersidad Nac ional Autónoma de Méx ico, Ciudad Universitari a, Apartado Po stal 70-39 9, Méx ico 04510, D.F., Méx ico . e-mail : il v@ hp.fcie ncias .un am.m x Resumen . El bo squ e m esófil o ele Mol ocotlán a barca parte ele d os muni cipi os del es tad o el e Hid algo, Mo la ngo y Xochi coatl á n , a mb os enclavados d e nt ro ele la Sierra Madre O rie n ta l, e n la Hu asteca Hi cla lg ue nse . El bosqu e prese nta tres es tratos a rbóreos, un o alto (2 0-30 m ), un o medi o (8-20 m ) )' un o baj o (2-8 m ). Se prese nta una li sta florísti ca ele plantas vasc ul a res co nstituida po r 391 esp ec ies, 270 gé neros y l 12 fa mili as. Los gé n e r os se agrup aro n ele acu e rdo co n su di stribu ció n actual e n se is ca tego rías; un alto po rce n taj e el e e ll os son e xclusiva m e nte am erica nos. Palabras clave: Bosque rn esó fil o el e mo nta11a, fl o rísti ca, fl o ra mesoa me ri can a, Hidalgo . Abstract. Th e clo ucl forest o f Mol ocotl á n inclucles part of two muni cipali ties of th e Hidalgo Sta te, Mo la ngo a ncl Xo chi coatl á n , a ncl is loca te cl in th e Huas teca reg io n in th e Si e rra Madre Ori e ntal. Arb o rea l vege tatio n is clivicl ecl in three ve rti ca l strata: high (20-30 m), meclium (8-20 m) , ancl lowe r (2-8 m). Th e fl o ra of th e a rea in clucles 39 1 sp ec ies, 270 ge ne ra, a ncl 112 famili es . Ge nera a re gro upecl acco rclin g to th e ir prese nt cli stribution in si x ca tegori es; a high pe rcentaj e o f th e m are exclusively Ame ri ca n.

Climatic variations influence the adaptive capacity of trees within tropical montane cloud forests species. Phenology studies have dominated current studies on tree species. Leaf vein morphology has been related to specific climatic oscillations and varies within species along altitudinal gradients. We tested that certain Neotropical broad leaf Magnolia species might be more vulnerable to leaf vein adaptation to moisture than others, as they would be more resilient to the hydric deficit. We assessed that leaf vein trait variations (vein density, primary vein size, vein length, and leaf base angle) among four Magnolia species (Magnolia nuevoleonensis, M. alejandrae, M. rzedowskiana, and Magnolia vovidesii) through the Mexican Tropical montane cloud forest with different elevation gradient and specific climatic factors. The temperature, precipitation, and potential evaporation differed significantly among Magnolia species. We detected that M. rzedowskiana and M. vovidesii with longer leaves at higher altitude sites are adapted to higher humidity conditions, and that M. nuevoleonensis and M. alejandrae inhabiting lower altitude sites are better adjusted to the hydric deficit. Our results advance efforts to identify the Magnolia species most vulnerable to climate change effects, which must focus priorities for conservation of this ecosystem, particularly in the Mexican tropical montane cloud forests.

A new species of Ternstroemia, T. guerrerensis O. Alcántara-Ayala, I. Luna-Vega, F. S. Maradiaga-Ceceña & H. Alvarado-Sizzo, is molecular, phylogenetically, and morphologically described and illustrated from Guerrero, Mexico. This short tree inhabits disturbed areas of the tropical montane cloud forest (TMCF), with Magnolia vazquezii and different oaks as dominant species in the canopy. This new species is related to T. lineata subsp. lineata, but differs from the latter in the shape and apex of the leaves, peduncle length and color, petiole color, and length of the connective prolongation of the anthers.