Oreocarya crassipes, an endangered angiosperm native to the Trans-Pecos region in southern Brewster County, Texas, exhibits distyly, a breeding system that includes two floral morphs with reciprocal positioning of the anthers and stigmas. The long-style (LS) morph has stigmas above the anthers, and the short-style (SS) morph produces anthers above the stigmas. In the present study, multiple aspects of distyly were examined across four populations of O. crassipes including morph ratios, variation in floral morphology, and patterns of macroscopic and microscopic floral development of the morphs. Morph ratios vary among populations, but for all of the samples pooled the ratio was 1 LS:1 SS. Distyly was observed to be well established in the species, with stigma height, anther height, and stigma-anther separation significantly different between the two morphs. Floral developmental patterns are similar to those in related species, suggesting a conserved and similarly co-opted developmental pathway for the origin of distyly in the genus and relatives.

Mixed mating is thought to be adaptive in many species of flowering plants because self-fertilization provides reproductive assurance when pollinator densities are low. In species with dimorphic flowers, automatic self-fertilization by small cleistogamous (CL) flowers might also provide reproductive assurance by avoiding floral herbivory. We tested this hypothesis by quantifying flower production, seed production, and seed predation across an entire reproductive season within a Missouri population of Ruellia humilis, a species with mixed mating enforced by dimorphic flowers. The production of CL flowers was delayed relative to the production of open-pollinated chasmogamous (CH) flowers, consistent with the hypothesis of reproductive assurance. The rate of seed predation by larvae of the Noctuid moth Tripudia rectangula was much higher for fruits produced by CH flowers (69%) than by CL flowers (18%). Thus, although CH flowers self-pollinate in the absence of outcross pollen, CL flowers are a much more economical source of selfed seeds, not only because they require fewer resources but also because they experience much lower levels of seed predation. Seed predation by Tripudia is common in many other cleistogamous species of Ruellia native to the southern United States and Mexico and might have played a significant role in the evolution of CL flowers in this large genus.

Retaliatory killing of large carnivores due to livestock predation is one of the major threats for the conservation of many declining populations of predators. According to empirical observations, there is a higher incidence of livestock predation when native prey abundance is low. In this study, we applied a treatment consisting of augmentation of prey abundance by translocation of peccaries (Pecari tajacu) and placement of four feed stations for white-tailed deer (Odocoileus virginianus) on a cattle ranch in Sonora, Mexico, with verified calf predation by puma (Puma concolor) and jaguar (Panthera onca). We quantified and compared consumed prey over two periods—phase I (8 months before the augmentation of prey) and phase II (8 months after the augmentation of prey)—through investigation of kill sites from Global Positioning System–collared jaguar and puma, prey identification from analyzed scat using molecular DNA techniques, and opportunistic discoveries of recently killed animal remains by either predator. We calculated the relative abundance of species (17 mammals [one species with two distinct age classes] and 1 bird species) through camera traps and for the most relevant prey species for this study (deer, calf, and peccary), we also estimated prey use by the predator, based on their availability during each period (prey preference). In the prey composition analyses of scat, we observed a significant reduction in the consumption of bovids and a significant increase in the consumption of peccaries during phase II. In the analyses of prey use, during phase I, predators consumed peccaries and calves at a higher proportion in relation to their availability. During phase II, consumption of calves declined from being preferred, to being consumed at the same proportion as their availability. Application of these results can contribute to the decrease of livestock predation and therefore conservation of pumas and jaguars.

The average number of arms on a saguaro (Carnegiea gigantea) increases with saguaro height, but there is considerable variation among saguaros for any given height. This variation has been largely attributed to variation in water availability among individual plants. To test this hypothesis, I recorded the height and number of arms of a sample of 425 saguaros within Organ Pipe Cactus National Monument along with values of three variables that should affect arm production through their effect on water availability: (1) the number of neighboring saguaros under the same nurse tree canopy, (2) the presence of a wash within 5 m, and (3) the presence and identity of any living or dead plant associate. Deviation from the number of arms expected for a given saguaro height was negatively related to the number of saguaro neighbors and positively related to the presence of a nearby wash. Saguaros growing with live associates also had fewer arms than those growing alone, and saguaros growing with dead associates had more arms than those growing alone. Each of these results is consistent with the idea that arm production is affected by water availability.

We tested whether individual females of two species of aquatic turtles, Texas cooters (Pseudemys texana) and red-eared sliders (Trachemys scripta elegans), inhabiting headwaters of the San Marcos River, Hays County, Texas, selectively used the same nesting areas within and among years over a 20-year period. The study area was divided into four quadrants, and chi-square analyses confirmed that for within and among years, females of both species selected quadrants unequally. Our results thus confirm that females of both species at the study site exhibited nest area fidelity within and among years.

Coefficients of Conservatism (C-values) are used in Floristic Quality Assessment to evaluate the level of anthropogenic disturbance of a given natural area and exist for much of the United States; however, there is a gap in the southwestern United States. We aim to close this gap by establishing C-values for the flora of the Middle Rio Grande floodplain in New Mexico. We compiled a list of species found in the floodplain (n = 621), and two regional botanists assigned C-values on a scale from 0 to 10 (0 reserved for nonnative taxa and the least conservative native taxa, and 10 being the most conservative). We used correlation analysis to examine the relationship of C-values assigned between botanists as well as shared species between Colorado and New Mexico. There was a significant, but weak, positive correlation between C-values for the two states, highlighting ecoregional similarities and providing a basis of comparison for our C-values. Descriptive statistics indicate the range of C-values assigned are consistent with the disturbance history of the region.

We describe dung pellets identified as bighorn sheep (Ovis canadensis; Bovidae, Caprinae) radiocarbon dated to ∼12,500 cal BP, late Pleistocene. Pellets were excavated from a layer of trampled and butchered bison bones in Eagle Cave located in a box canyon tributary of the entrenched Rio Grande, southwestern Texas. Wild sheep are not known historically or from the Pleistocene from this region of the Lower Pecos Canyonlands. Phytolith analysis of the fossil dung revealed that the Ovis diet was predominantly a mixture of cool and warm season grasses, but dominated by warm season grasses. Morphology and content analysis imply that the dung represent a late-summer, or more likely, winter season accumulation.

White-tailed jackrabbits (Lepus townsendii) were once abundant in North America and provided a number of ecosystem services such as seed dispersal, nutrient cycling, facilitating the persistence of other species, and serving as a prey species for predators, including golden eagles (Aquila chrysaetos), bobcats (Lynx rufus), and numerous others. Reports describe declines and extirpations across much of their range, but given the extremely limited research available, it is difficult to determine what factors have led to reductions of white-tailed jackrabbits. Researchers have investigated few areas of white-tailed jackrabbit ecology, including the possible effects of climate change, habitat degradation and loss, competition with black-tailed jackrabbits (Lepus californicus), and changes in predator composition. We review the life history and research available on white-tailed jackrabbits, discuss possible causes of their decline, suggest areas that require additional research, and make recommendations regarding their management.

Eryngium sparganophyllum is an imperiled plant species with a small geographic range in the southwestern United States and northern Mexico and is restricted to wetlands known as cienegas. We compiled information on its population status, habitat, life history, and threats to inform conservation and recovery efforts and to guide future research. Of the six historically documented populations, this species has been extirpated at two and remains extant in four. Extractions of groundwater or diversions of spring discharge are the greatest threats, exacerbated by reduced groundwater inflow to cienegas because of regional drought and temperature increases. Eryngium sparganophyllum is locally common in its known sites, but woody encroachment may be a threat, as field data in Arizona reveal the plants to be more abundant in open sun than under tree canopy. Plants flower within their first year and host a wide range of invertebrate visitors. Experimental techniques confirm seed viability with a morphophysiological dormancy; however, patterns of seedling establishment in the wild remain undocumented. Reintroduction at two sites is being implemented and long-term monitoring of survivorship and fecundity of these transplants is necessary to guide future recovery efforts.

Two sightings of bobcat (Lynx rufus) were obtained in northeastern San Luis Potosí. These records extend the geographic range of the species ca. 55 km south of Tamaulipas and 230 km southeast in San Luis Potosí.

We report records of the white-sided jackrabbit (Lepus callotis) for Oaxaca, Mexico, 3 years after the last report, and confirm its presence in the Valles Centrales after 116 years. Our data extend by 42 km the southernmost limit of L. callotis.

Golden shiner (Notemigonus crysoleucas) and rudd (Scardinius erythrophthalmus) have been hybridized in a laboratory experiment and a hatchery setting but have not been reported in wild populations. Here we report the presence of golden shiner × rudd hybrids in the wild in Lake San Isabel, Colorado, where both parental species maintain reproducing populations. The hybrid was identified based on intermediate squamation of the keel (cultrate abdomen), where a small fleshy ridge was present at the posterior edge of the keel adjacent to the vent. In contrast, the keel of the golden shiner lacks squamation entirely while the keel of the rudd is completely covered by scales.