Alondra Castro-Campillo

Systematic status of Peromyscus Boylii ambiguus based on morphologic and molecular data

Recent chromosomal and allozymic studies suggest that Peromyscus boylii ambiguus is aligned more closely to P. levipes than to P. b. rowleyi. To clarify taxonomic and systematic status of this taxon, univariate and multivariate morphometric analyses were conducted on representative specimens of P. b. rowleyi, P. b. ambiguus, P. levipes, and P. beatae (hereafter referred to as rowleyi, ambiguus, levipes, and beatae). In addition, DNA sequences of the mitochondrial D-loop region were examined in exemplars representing each taxon to further assess the phylogenetic relationship of ambiguus to other members of the P. boylii species group. The morphological study revealed a consistent pattern of increasing size from north to south. Most multivariate analyses separated ambiguus and beatae from rowleyi and showed phenetic affinities between ambiguus and levipes. DNA-sequence data revealed a sister-taxon relationship between ambiguus and levipes to the exclusion of rowleyi and beatae. Morphological and DNA-sequence data are in agreement with previous karyotypic and allozymic studies supporting affinities between ambiguus and levipes. Based on concordance of these four data sets, it is apparent that these two taxa represent subunits within levipes, the ranges of which are divided approximately at the Tropic of Cancer in northeastern Mexico. The appropriate taxonomic designation for ambiguus is as a subspecies of levipes.

Systematics of the Smooth-Toothed Pocket Gopher,Thomomys umbrinus, in the Mexican Transvolcanic Belt

Abstract Difficulties in the subspecific identification of more than 200 specimens of Thomomys umbrinus from the State of Tlaxcala led us to examine the systematic status of the eight subspecies recognized within the Mexican Transvolcanic Belt. We gathered representative samples of those subspecies (≥ 50) during three years of fieldwork. These were analyzed together with samples from other populations not previously assigned to subspecies, as well as voucher specimens from several collections. Thirty-seven variables, obtained from 1145 specimens, were analyzed morphometrically using univariate and multivariate statistics. Within-population variation was highly influenced by sexual dimorphism, and especially by ontogenetic variation; therefore, these two factors should be considered carefully when making systematic and taxonomic decisions. Our analysis of geographic variation determined only two recognizable subspecies of Thomomys umbrinus within the Mexican Transvolcanic Belt: Thomomys umbrinus umbrinus (Richardson, 1829) and Thomomys umbrinus pullus Hall and Villa, 1948.

Spatial and Temporal Changes in Habitat Heterogeneity Promote Partition of Resources by Syntopic Small Mammals in a Midlatitude Temperate Forest

One of the basics and fundamentals problems in ecology is understand the factors that shape the spatial patterns in the distribution of the species and the coexistence of close relatives species. Among the most important factors governing the distributions and the coexistence of species are the spatiotemporal changes occurring in the microhabitat heterogeneity. Here, we assessed the heterogeneity of microhabitats and how they have an effect in the spatial segregation of two species of small mammals (i. e., Peromyscus difficilis and P. melanotis), which coexist in a temperate, mixed forest. We evaluated the microhabitat heterogeneity through multivariate statistics, using onto 23 habitat variables for vertical-horizontal habitat structure along pluvial seasons. To detect specific microdistribution changes and habitat preferences by two species of small mammals, we used second order spatial statistics and general linear models. According to their respective morphology and locomotive adaptations, the middle sized, midscansorial P. difficilis was resident all year long and preferred microhabitats with a high log ground cover, while the opportunistic, small sized, cursorial P. melanotis changed its occupancy area, depending on density of herbaceous and woody plants cover. Under the more benign microhabitat conditions of rainy season (denser plant coverage, milder temperature), both species showed closer microdistribution patterns; while these became repulsive at the less benign conditions of dry season (scarcer plant cover, colder temperature). Thus, we could confirm that seasonal changes of microhabitat heterogeneity promoted Peromyscus coexistence, through dispersion patterns reflecting partition of microhabitat resources.To understand how spatiotemporal changes of microhabitat heterogeneity affect coexistence of syntopic Peromyscus within a temperate, mixed forest, along pluvial seasons, we assessed microhabitat zones through multivariate statistics, using onto 23 habitat variables for vertical-horizontal habitat structure. To detect specific microdistribution changes and habitat preferences by the species, we used second order spatial statistics and general linear models. According to their respective morphology and locomotive adaptations, the middle sized, midscansorial Peromyscus difficilis was resident all year long and preferred microhabitats with a high log ground cover, while the opportunistic, small sized, cursorial P. melanotis changed its occupancy area, depending on density of herbaceous and woody plants cover. Under the more benign microhabitat conditions of rainy season (denser plant coverage, milder temperature), both species showed closer microdistribution patterns; while these became repulsive at the less benign conditions of dry season (scarcer plant cover, colder temperature). Thus, seasonal changes of microhabitat heterogeneity promoted Peromyscus coexistence, through dispersion patterns reflecting partition of microhabitat resources. Key words: Microhabitat selection, Use of space, Small mammals, Dispersion, Resource partition.Abstract One basic issue in ecology is to understand how seasonal spatiotemporal shifts in habitat heterogeneity shape spatial patterns in the distribution and coexistence of organisms. For example, how do spatial dispersion of syntopic species reflects their respective resource preferences and partition, during microhabitat seasonal shifts? To address this, we assessed changes in microhabitat structure heterogeneity, between the two annual seasons (dry and rainy seasons) in a midlatitude temperate forest by analyzing 23 habitat variables using multivariate statistics. Furthermore, to determine how such microhabitat changes affected the spatial segregation of two congeneric species of small mammals (Peromyscus difficilis, P. melanotis), we used second-order spatial statistics to detect changes in their microdistribution changes and general linear models to evaluate their habitat preferences. In accordance with their respective morphology and ambulatory habits, the medium-sized, semi-scansorial P. difficilis was resident year-round and preferred microhabitats with high amounts of log ground cover, while the small, opportunistic, cursorial P. melanotis varied its occupancy area depending on the density of herbaceous and cover of woody plants. Both species showed more similar microdistribution patterns under the more benign microhabitat conditions of the rainy season (denser plant coverage, humid-cool weather), but became more segregated form each other during the less favorable conditions of the dry season (scarcer plant coverage, dry-cold weather). Therefore, seasonal changes in microhabitat heterogeneity influenced the dispersion patterns of both Peromyscus species and revealed their temporal preferences for microhabitat resources.One of the basics problems in ecology is to understand the factors that shape the spatial patterns in the distribution of the species and the coexistence of close relatives species. Among the most critical factors governing the distributions and the coexistence of species are the spatiotemporal changes occurring in the microhabitat heterogeneity. Here, we assessed the heterogeneity of microhabitats and how they affect the spatial segregation of two species of small mammals (i. e., Peromyscus difficilis and P. melanotis), which coexist in a temperate, mixed forest. We evaluated the microhabitat heterogeneity through multivariate statistics, using onto 23 habitat variables describing horizontal-vertical habitat structure along pluvial seasons. To detect specific microdistribution changes and habitat preferences by two species of small mammals, we used second-order spatial statistics and general linear models. According to their respective morphology and locomotive adaptations, the middle sized, midscansorial P. difficilis was resident all year long and preferred microhabitats with a high log ground cover, while the opportunistic, small sized, cursorial P. melanotis changed its occupancy area, depending on the density of herbaceous and woody plants cover. Under the more benign microhabitat conditions of the rainy season (denser plant coverage, milder temperature), both species showed closer microdistribution patterns; while these became repulsive at the less favorable conditions of the dry season (scarcer plant cover, colder temperature). Thus, we could confirm that seasonal changes of microhabitat heterogeneity promoted Peromyscus coexistence, through dispersion patterns reflecting partition of microhabitat resources.

Microhabitat Heterogeneity Promotes Partition of Resources by Syntopic Peromyscus in a Midlatitude Temperate Forest

One of the basics and fundamentals problems in ecology is understand the factors that shape the spatial patterns in the distribution of the species and the coexistence of close relatives species. Among the most important factors governing the distributions and the coexistence of species are the spatiotemporal changes occurring in the microhabitat heterogeneity. Here, we assessed the heterogeneity of microhabitats and how they have an effect in the spatial segregation of two species of small mammals (i. e., Peromyscus difficilis and P. melanotis), which coexist in a temperate, mixed forest. We evaluated the microhabitat heterogeneity through multivariate statistics, using onto 23 habitat variables for vertical-horizontal habitat structure along pluvial seasons. To detect specific microdistribution changes and habitat preferences by two species of small mammals, we used second order spatial statistics and general linear models. According to their respective morphology and locomotive adaptations, the middle sized, midscansorial P. difficilis was resident all year long and preferred microhabitats with a high log ground cover, while the opportunistic, small sized, cursorial P. melanotis changed its occupancy area, depending on density of herbaceous and woody plants cover. Under the more benign microhabitat conditions of rainy season (denser plant coverage, milder temperature), both species showed closer microdistribution patterns; while these became repulsive at the less benign conditions of dry season (scarcer plant cover, colder temperature). Thus, we could confirm that seasonal changes of microhabitat heterogeneity promoted Peromyscus coexistence, through dispersion patterns reflecting partition of microhabitat resources.To understand how spatiotemporal changes of microhabitat heterogeneity affect coexistence of syntopic Peromyscus within a temperate, mixed forest, along pluvial seasons, we assessed microhabitat zones through multivariate statistics, using onto 23 habitat variables for vertical-horizontal habitat structure. To detect specific microdistribution changes and habitat preferences by the species, we used second order spatial statistics and general linear models. According to their respective morphology and locomotive adaptations, the middle sized, midscansorial Peromyscus difficilis was resident all year long and preferred microhabitats with a high log ground cover, while the opportunistic, small sized, cursorial P. melanotis changed its occupancy area, depending on density of herbaceous and woody plants cover. Under the more benign microhabitat conditions of rainy season (denser plant coverage, milder temperature), both species showed closer microdistribution patterns; while these became repulsive at the less benign conditions of dry season (scarcer plant cover, colder temperature). Thus, seasonal changes of microhabitat heterogeneity promoted Peromyscus coexistence, through dispersion patterns reflecting partition of microhabitat resources. Key words: Microhabitat selection, Use of space, Small mammals, Dispersion, Resource partition.Abstract One basic issue in ecology is to understand how seasonal spatiotemporal shifts in habitat heterogeneity shape spatial patterns in the distribution and coexistence of organisms. For example, how do spatial dispersion of syntopic species reflects their respective resource preferences and partition, during microhabitat seasonal shifts? To address this, we assessed changes in microhabitat structure heterogeneity, between the two annual seasons (dry and rainy seasons) in a midlatitude temperate forest by analyzing 23 habitat variables using multivariate statistics. Furthermore, to determine how such microhabitat changes affected the spatial segregation of two congeneric species of small mammals (Peromyscus difficilis, P. melanotis), we used second-order spatial statistics to detect changes in their microdistribution changes and general linear models to evaluate their habitat preferences. In accordance with their respective morphology and ambulatory habits, the medium-sized, semi-scansorial P. difficilis was resident year-round and preferred microhabitats with high amounts of log ground cover, while the small, opportunistic, cursorial P. melanotis varied its occupancy area depending on the density of herbaceous and cover of woody plants. Both species showed more similar microdistribution patterns under the more benign microhabitat conditions of the rainy season (denser plant coverage, humid-cool weather), but became more segregated form each other during the less favorable conditions of the dry season (scarcer plant coverage, dry-cold weather). Therefore, seasonal changes in microhabitat heterogeneity influenced the dispersion patterns of both Peromyscus species and revealed their temporal preferences for microhabitat resources.One of the basics problems in ecology is to understand the factors that shape the spatial patterns in the distribution of the species and the coexistence of close relatives species. Among the most critical factors governing the distributions and the coexistence of species are the spatiotemporal changes occurring in the microhabitat heterogeneity. Here, we assessed the heterogeneity of microhabitats and how they affect the spatial segregation of two species of small mammals (i. e., Peromyscus difficilis and P. melanotis), which coexist in a temperate, mixed forest. We evaluated the microhabitat heterogeneity through multivariate statistics, using onto 23 habitat variables describing horizontal-vertical habitat structure along pluvial seasons. To detect specific microdistribution changes and habitat preferences by two species of small mammals, we used second-order spatial statistics and general linear models. According to their respective morphology and locomotive adaptations, the middle sized, midscansorial P. difficilis was resident all year long and preferred microhabitats with a high log ground cover, while the opportunistic, small sized, cursorial P. melanotis changed its occupancy area, depending on the density of herbaceous and woody plants cover. Under the more benign microhabitat conditions of the rainy season (denser plant coverage, milder temperature), both species showed closer microdistribution patterns; while these became repulsive at the less favorable conditions of the dry season (scarcer plant cover, colder temperature). Thus, we could confirm that seasonal changes of microhabitat heterogeneity promoted Peromyscus coexistence, through dispersion patterns reflecting partition of microhabitat resources.

Assessing the Relation between the Spatiotemporal Microhabitat Heterogeneity and the Dispersion Patterns of Two Syntopic Small Mammals in a Midlatitude Temperate Forest

One of the basics and fundamentals problems in ecology is understand the factors that shape the spatial patterns in the distribution of the species and the coexistence of close relatives species. Among the most important factors governing the distributions and the coexistence of species are the spatiotemporal changes occurring in the microhabitat heterogeneity. Here, we assessed the heterogeneity of microhabitats and how they have an effect in the spatial segregation of two species of small mammals (i. e., Peromyscus difficilis and P. melanotis), which coexist in a temperate, mixed forest. We evaluated the microhabitat heterogeneity through multivariate statistics, using onto 23 habitat variables for vertical-horizontal habitat structure along pluvial seasons. To detect specific microdistribution changes and habitat preferences by two species of small mammals, we used second order spatial statistics and general linear models. According to their respective morphology and locomotive adaptations, the middle sized, midscansorial P. difficilis was resident all year long and preferred microhabitats with a high log ground cover, while the opportunistic, small sized, cursorial P. melanotis changed its occupancy area, depending on density of herbaceous and woody plants cover. Under the more benign microhabitat conditions of rainy season (denser plant coverage, milder temperature), both species showed closer microdistribution patterns; while these became repulsive at the less benign conditions of dry season (scarcer plant cover, colder temperature). Thus, we could confirm that seasonal changes of microhabitat heterogeneity promoted Peromyscus coexistence, through dispersion patterns reflecting partition of microhabitat resources.To understand how spatiotemporal changes of microhabitat heterogeneity affect coexistence of syntopic Peromyscus within a temperate, mixed forest, along pluvial seasons, we assessed microhabitat zones through multivariate statistics, using onto 23 habitat variables for vertical-horizontal habitat structure. To detect specific microdistribution changes and habitat preferences by the species, we used second order spatial statistics and general linear models. According to their respective morphology and locomotive adaptations, the middle sized, midscansorial Peromyscus difficilis was resident all year long and preferred microhabitats with a high log ground cover, while the opportunistic, small sized, cursorial P. melanotis changed its occupancy area, depending on density of herbaceous and woody plants cover. Under the more benign microhabitat conditions of rainy season (denser plant coverage, milder temperature), both species showed closer microdistribution patterns; while these became repulsive at the less benign conditions of dry season (scarcer plant cover, colder temperature). Thus, seasonal changes of microhabitat heterogeneity promoted Peromyscus coexistence, through dispersion patterns reflecting partition of microhabitat resources. Key words: Microhabitat selection, Use of space, Small mammals, Dispersion, Resource partition.Abstract One basic issue in ecology is to understand how seasonal spatiotemporal shifts in habitat heterogeneity shape spatial patterns in the distribution and coexistence of organisms. For example, how do spatial dispersion of syntopic species reflects their respective resource preferences and partition, during microhabitat seasonal shifts? To address this, we assessed changes in microhabitat structure heterogeneity, between the two annual seasons (dry and rainy seasons) in a midlatitude temperate forest by analyzing 23 habitat variables using multivariate statistics. Furthermore, to determine how such microhabitat changes affected the spatial segregation of two congeneric species of small mammals (Peromyscus difficilis, P. melanotis), we used second-order spatial statistics to detect changes in their microdistribution changes and general linear models to evaluate their habitat preferences. In accordance with their respective morphology and ambulatory habits, the medium-sized, semi-scansorial P. difficilis was resident year-round and preferred microhabitats with high amounts of log ground cover, while the small, opportunistic, cursorial P. melanotis varied its occupancy area depending on the density of herbaceous and cover of woody plants. Both species showed more similar microdistribution patterns under the more benign microhabitat conditions of the rainy season (denser plant coverage, humid-cool weather), but became more segregated form each other during the less favorable conditions of the dry season (scarcer plant coverage, dry-cold weather). Therefore, seasonal changes in microhabitat heterogeneity influenced the dispersion patterns of both Peromyscus species and revealed their temporal preferences for microhabitat resources.One of the basics problems in ecology is to understand the factors that shape the spatial patterns in the distribution of the species and the coexistence of close relatives species. Among the most critical factors governing the distributions and the coexistence of species are the spatiotemporal changes occurring in the microhabitat heterogeneity. Here, we assessed the heterogeneity of microhabitats and how they affect the spatial segregation of two species of small mammals (i. e., Peromyscus difficilis and P. melanotis), which coexist in a temperate, mixed forest. We evaluated the microhabitat heterogeneity through multivariate statistics, using onto 23 habitat variables describing horizontal-vertical habitat structure along pluvial seasons. To detect specific microdistribution changes and habitat preferences by two species of small mammals, we used second-order spatial statistics and general linear models. According to their respective morphology and locomotive adaptations, the middle sized, midscansorial P. difficilis was resident all year long and preferred microhabitats with a high log ground cover, while the opportunistic, small sized, cursorial P. melanotis changed its occupancy area, depending on the density of herbaceous and woody plants cover. Under the more benign microhabitat conditions of the rainy season (denser plant coverage, milder temperature), both species showed closer microdistribution patterns; while these became repulsive at the less favorable conditions of the dry season (scarcer plant cover, colder temperature). Thus, we could confirm that seasonal changes of microhabitat heterogeneity promoted Peromyscus coexistence, through dispersion patterns reflecting partition of microhabitat resources.