Northwest Mexico Research Articles

Depositional environments and transgression-regression cycles in the Mural Limestone, central Sonora, Mexico

Results of analytical studies in the Mural Limestone of the Bisbee Group exposed in northwest Mexico, carried out to determine the paleo-bathymetry of the marine depositional environment, reveal that deposition occurred in a restricted carbonate platform environment, varying from inner-neritic to shelf margin with the development of lagoon, shoal and biohermal conditions, reflecting minor transgression-regression cycles. Furthermore, the fossiliferous content and lithological characteristics support the interpretation that the studied section corresponds to the transition between Cerro La Puerta and Cerro La Espina members of the Mural Limestone.

Understanding Turkey Management in the Mimbres Valley of Southwestern New Mexico Using Ancient Mitochondrial DNA and Stable Isotopes

AbstractIn the US Southwest and Northwest Mexico, people and turkeys (Meleagris gallopavo) have had a reciprocal relationship for millennia; turkeys supplied feathers, meat, and other resources, whereas people provided food, shelter, and care. To investigate how turkeys fit within subsistence, economic production, sociopolitical organization, and religious and ritual practice in the Mimbres Valley of southwestern New Mexico, we report on genetic (mtDNA) and stable isotope (δ13C, δ15N) data from turkeys recovered from Mimbres Classic period (AD 1000–1130) sites. Results indicate that Mimbres aviculturists had haplogroup H1 and H2 turkeys, and most ate maize-based diets similar to humans, but some ate nonmaize and mixed diets. We contextualize these data to other turkey studies from the northern Southwest and discuss how the human-turkey relationship began, the evidence for pens and restricting turkey movement, and the socioecological factors related to turkey management during the Classic period, particularly the challenges associated with providing maize to turkeys during times of environmental stress. This study has broad relevance to places where people managed wild, tame, and domestic animals, and we offer new insights into how prehispanic, small-scale, middle-range agricultural societies managed turkeys for ritual and utilitarian purposes.

Recruitment patterns in Mexican geoduck (Panopea spp.) populations: Reconstruction from age structure and mortality parameters

The historic recruitment patterns of four populations of geoduck clams, Panopea generosa and P. globosa in northwest Mexico were analyzed by estimating a relative recruitment index (RRI) built from the age structure and mortality parameters. The RRI is a proportion of the strength of the year-class and is used as a measure of past recruitment intensities. Two recruitment patterns were observed: a) recruitments were relatively constant over time in the Punta Canoas and Puerto Peñasco populations, and b) recruitments occurred in erratic but strong pulses in the Bahía Magdalena and San Felipe populations; both of which were clearly dominant in year-classes 1988 and 1989. These differences are consistent with a strong metapopulational structure and with local conditions having an important role in recruitment regulation, thus suggesting the need to consider this structure in the design of management strategies to maintain sustainable fisheries. In particular, monitoring age classes may prove useful in identifying early changes in the recruitment patterns that may enable active management for each population.

Ecosystem-atmosphere CO2 exchange from semiarid mangroves in the Gulf of California

Mangrove wetlands play an essential role as blue carbon ecosystems. However, worldwide they also face imminent threats caused by anthropogenic activities and climate change. Mangroves in the semiarid region of the Gulf of California are highly vulnerable to both threats. In this study, we present eddy covariance measurements of net ecosystem exchange of CO2 (NEE), gross primary productivity (GPP), and ecosystem respiration (Reco) at a preserved mangrove (Estero El Sargento) and a site influenced by anthropogenic activities (Bahia del Tobari) located in northwest Mexico. Both sites were net annual carbon sinks but had different dynamics. The net annual carbon gain for Estero El Sargento was −717 g C m−2 y−1 while for Bahia deTobari was −247 g C m−2 y−1. Over the studied year, Estero El Sargento had lower Reco(329 g C m−2) during the winter-spring months and an overall lower annual Reco/GPP (0.42) than Bahia de Tobari. The Reco was notably high during the winter-spring period at Bahia de Tobari when agriculture drainage from the intensive food production activities at the Yaqui Valley reaches the bay. The contrasting NEE patterns and magnitude between both mangrove sites suggest that anthropogenic activities influencing coastal ecosystems exert an important control on the CO2 sink potential.

On predicting of some consequences of planned dam construction in a pristine sand-gravel river large catchment: Rio San Pedro, Nayarit, Northwest Mexico

The pressure on water and energy resources is increasing globally, particularly in emerging countries. Some of them use their rivers for electric power generation, paying little or no attention to the hydromorphological changes generated in the rivers due to the infrastructure associated. One case is the St. Pedro River in the Northwest of Mexico (Rio San Pedro), where it is planned to build a hydroelectric dam. The importance is due to its flow discharges directly to a marsh system called Marismas Nacionales, considered a Biosphere Reserve that includes approximately 20% of all mangroves in Mexico. The alteration of its natural conditions is a critical issue for the ecosystem. There are many studies about the effects of dams on rivers after their construction, but only a few related to the river characterization before intervention within its channel. In this work, we highlight the relevance of the latter. We conducted extensive fieldwork, including morphological survey, sediment transport measurement, hydrodynamics, and bathymetry over 80 km of the river. We establish a baseline with the hydromorphological parameters in the river and run a numerical simulation with 2-D HEC-RAS 6.1 model to compare natural and controlled runoff. The goal of our study was to discuss possible scenarios and some consequences that could be generated with the dam construction—alterations in the lower basin— and suggest actions that can help to minimize the detrimental consequences. The novelty of our work is the scope of fieldwork, the wide range of the data, careful modeling based on detailed field data, and finally, the possible way one might use our results in the future to minimize the adverse consequences of dam construction. The methodology presented can be used as a guide to other dam projects worldwide, which face all these issues and need to redesign the dam and consider modern techniques to preserve the riverine conditions close to the more natural possible.

Development of a Model for the Implementation of the Circular Economy in Desert Coastal Regions

Food production is the main challenge for developing arid regions due to the restricted access to fresh water. This study combines the environmental know-how of two coastal desert regions on the American continent with similar geographical characteristics to propose a general model for a circular economy in stressed environmental conditions. The Atacama Desert, located in Chile, is the driest place on Earth. Due to the lack of rainfall in decades, the possibility of growing food is almost impossible. The Desert of Sonora, in the northwest of Mexico, is known for its extreme aridity and temperatures over 50 °C in summer. Both deserts have continuously growing cities ranging from 400,000 to 900,000 inhabitants, where access to and management of freshwater represents an issue. A circular economy model was developed. Critical parameters for this model considered: the utilisation of solar energy for water desalination and energy production, integrated with hydroponic farming and water dosing with hydrogels for food production; microalgae for biofuels; seaweed for biochemicals; anaerobic digestion for organic waste management and nutrient recovery from wastewater sludge treatment. Regional policies and governance are needed to incentivise the adoption of circular economy models.

Structure of the Northern Altar Pull-Apart Basin Revealed by a 2D Reflection Seismic Survey: Evolution of the Gulf of California Shear Zone in Northwest Mexico

Structure of the Northern Altar Pull-Apart Basin Revealed by a 2D Reflection Seismic Survey: Evolution of the Gulf of California Shear Zone in Northwest Mexico

Gene expression in primary hemocyte culture of the Pacific white shrimp Penaeus vannamei infected with different white spot syndrome virus (WSSV) strains

Five previously analyzed white spot syndrome virus (WSSV) strains from northwest Mexico, differing in their genome architecture as well as in virulence, were selected (high virulence JP and LG strains; moderate virulence GVE and DIV strains; and low virulence LC10 strain) to evaluate pathogenesis response in vitro. Expression of phagocytosis-activating protein PAP, manganese superoxide dismutase MnSOD and peroxiredoxin PRX, and two genes of immediate-early expression (IE1 and WSSV304) were measured by qPCR in a primary hemocyte cell culture from Penaeus vannamei at 1, 3, 6, 12, and 24 h post-infection (hpi). PAP expression was significantly higher at 1 and 3 hpi, and JP and LC10 strains induced the highest expression. The response of MnSOD was high at 1 hpi, and a significant increase in PRX expression was detected at 3 hpi, probably due to the occurrence of an oxidative burst; expression levels of MnSOD and PRX were significantly higher at 1 and 3 hpi, respectively, induced by the LG strain (high virulence), suggesting an acute response. In general, expression of most immune-related - genes decreased after the initial hours of infection. Expression levels of IE1 and WSSV304 were exceptionally high at 1 hpi in almost all five WSSV analyzed strains, confirming their efficient mechanism for replication and viral fitness. The results of this study do not show an accurate link between the genome size and WSSV virulence of the strains, albeit the strain with the smallest genome showed the highest virulence. All strains induced an early immune response in heterogeneous ways.

Hot Extremes and Climatological Drought Indicators in the Transitional Semiarid-Subtropical Region of Sinaloa, Northwest Mexico

Hot Extremes and Climatological Drought Indicators in the Transitional Semiarid-Subtropical Region of Sinaloa, Northwest Mexico

External validation of BIA equations to estimate appendicular skeletal muscle mass in older adults: Importance of the bias analysis and derivation of correction factors to achieve agreement.

There are several equations based on bioelectrical impedance analysis (BIA) to estimate with high precision appendicular skeletal muscle mass (ASM). However, most of the external validation studies have reported that these equations are inaccurate or biased when applied to different populations. Furthermore, none of the published studies has derived correction factors (CFs) in samples of community-dwelling older adults, and none of the published studies have assessed the influence of the dual-energy X-ray absorptiometry (DXA) model on the validation process. This study assessed the agreement between six BIA equations and DXA to estimate ASM in non-Caucasian older adults considering the DXA model and proposed a CF for three of them. This analysis included 547 non-institutionalized subjects over 60 years old from the northwest of Mexico who were physically independent and without cognitive impairment: 192 subjects were measured using DXA Hologic, while 355 were measured by DXA Lunar. The agreement between each of the equations and DXA was tested considering the DXA model used as a reference method for the design of each equation, using the Bland and Altman procedure, a paired t test, and simple linear regression as objective tests. This process was supported by the differences reported in the literature and confirmed in a subsample of 70 subjects measured with both models. Only six published BIA equations were included. The results showed that four equations overestimated ASMDXA, and two underestimated it (p < 0.001, 95% CI for Kim's equation:−5.86-−5.45, Toselli's:−0.51-−0.15, Kyle's: 1.43–1.84, Rangel-Peniche's: 0.32–0.74, Sergi's: 0.83–1.23, and Yoshida's: 4.16–4.63 kg). However, Toselli's, Kyle's and Rangel-Peniche's equations were the only ones that complied with having a homogeneous bias. This finding allowed the derivation of CFs, which consisted of subtracting or adding the mean of the differences from the original equation. After estimating ASM applying the respective CF, the new ASM estimations showed no significant bias and its distribution remained homogeneously distributed. Therefore, agreement with DXA in the sample of non-Caucasian was achieved. Adding valid CFs to some BIA equations allowed to reduce the bias of some equations, making them valid to estimate the mean values of ASM at group level.

Using a Sensitivity Analysis and Spatial Clustering to Determine Vulnerability to Potentially Toxic Elements in a Semiarid City in Northwest Mexico

The Getis-Ord Gi* statistic clustering technique was used to create a hot spot exposure map using 14 potentially toxic elements (PTEs) found in urban dust samples in a semiarid city in northwest Mexico. The dust distribution and deposition in this city are influenced by the seasonal wind and rain from the North American Monsoon. The spatial clustering patterns of hot spots were used in combination with a sensitivity analysis to determine which variables most influenced the PTE hot spot exposure base map. The hot spots areas (%) were used as indicators of environmental vulnerability, and a final integrated map was selected to represent the highest vulnerability of PTEs with a 99% level of confidence. The results of the sensitivity analysis indicated that the flood zones and pervious and impervious zones were the most sensitive variables due to their weight in the spatial distribution. The hot spot areas were reduced by 60.4% by not considering these variables. The hot spot analysis resulted in an effective tool that allowed the combination of different spatial layers with specific characteristics to determine areas that present greater vulnerability to the distribution of PTEs, with impacts on public and environmental health.

Prevalence of food addiction and its association with lifestyle factors in undergraduate students from Northwest Mexico

Background: The aim of this study was to determine the prevalence of food addiction (FA) in undergraduate students from Northwest Mexico and to examine its association with lifestyle factors, eating behaviors and food consumption.Methods: This cross-sectional study included a total of 326 undergraduate students, both sexes, between 18 and 25 years of age, who were enrolled in a bachelor’s degree program at a public or private university in the city of Tijuana, Baja California, Mexico. FA was assessed using the modified Yale Food Addiction Scale Version 2.0 (mYFAS 2.0). Lifestyle (sleep patterns, physical exercise, alcohol intake, and smoking) and nutritional information (eating behaviors and food frequency consumption) was obtained through a clinical history. A multivariate logistic regression model was fitted to assess the factors associated with FA.Results: The whole prevalence of FA was 12.9%. In general, mild FA was the most frequent (5.2%), followed by severe (4.3%) and moderate (3.4%) categories. In the multivariate model, insomnia conferred a higher risk for FA (OR = 2.08, 95% CI, 1.04–4.17, p = 0.040), while the habitual consumption of fruits showed a protective effect (OR = 0.50, 95% CI, 0.25–0.98, p = 0.046). Overall, the model predicted FA in 12% (R2=0.12, p = 0.011).Conclusion: The prevalence of FA is 12.9% among undergraduate students from Northwest Mexico. Although caution should be exercised, insomnia seems to increase the risk of FA, while the habitual consumption of fruits appears to have a protective role. Additional studies are needed to validate these results.

Land use and land cover changes resulting from the urban El Molinito reservoir in the drying Sonoran River Basin

ABSTRACT Although the impacts of dams on the environment and human populations have been widely documented, many developing countries continue constructing large dams. In Mexico, impact studies have neglected to analyze downstream effects of dams. Thus, we analyzed land use and land cover (LULC) changes downstream of El Molinito dam, constructed on the Sonora River in northwest Mexico. We used Landsat Thematic Mapper (TM) to generate classifications (for 1993, 2002 and 2011), from which an assessment is performed to identify the principal changes. In addition, we analyzed changes in photosynthetic activity using the simple but informative Normalized Difference Vegetation Index (NDVI). We found a drastic decline between 1993 and 2011 in agricultural LULC because of water diversions from El Molinito. This study demonstrates the need for agencies responsible for water management to better assess the negative effects of dam construction and operation, especially on the livelihoods of downstream rural communities.

Hydroalcoholic extracts of Parkinsonia aculeata: a sustainable alternative for the biocontrol of Fusarium oxysporum

&#x0D; Fusarium, caused by Fusarium oxysporum Schlecht, generates significant losses in important crops in the Northwest Mexico, mainly in the State of Sonora. Given the need to reduce polluting loads due to the use of commercial fungicides, the use of sustainable ecological biotechnological alternatives such as plant extracts for disease biocontrol is a partial solution in both organic and traditional production systems. The present work aimed to evaluate the antifungal potential of hydroalcoholic extracts from leaves and stems of Parkinsonia aculeata L., Sp. Pl. (palo verde) for Fusarium oxysporum Schlecht biocontrol. Plant samples were taken from two semi-arid ecosystems (Bahía de Lobos, Site 1, and Tesopaco, Site 2). This samples were used to obtain and apply two volumes of hydroalcoholic extracts (300 and 500 ppm) in the culture medium prepared for the mycelial growth of Fusarium oxysporum Schlecht. As a control, distilled water was used to evaluate the free mycelial growth (dependent variable) and the commercial fungicide (TIABENDAZOL) for the total control of the fungus. These extracts were added to culture media using the poison culture medium technique. The treatments were placed in a growth chamber, following a completely randomized experimental design with a trifactorial arrangement. The extracts of Parkinsonia aculeata L., Sp. Pl. from both sites and volumes (300 ppm, and at 500 ppm) showed effectiveness for mycelial growth inhibition. There was a highly significant interaction between the three established factors. The source of variation with the greatest contribution to the total variability found was the volume in the culture medium. The minimum inhibitory volume of the hydroalcoholic extract was 289 ppm and the lethal least squared volume was 444 ppm in the culture medium. The obtained results confirm the viability of using hydroalcoholic extracts of Parkinsonia aculeata L., Sp. Pl.as a sustainable alternative for Fusarium oxysporum Schlecht biocontrol of in the agricultural production systems of northwestern Mexico. &#x0D;

Overfishing Increases the Carbon Footprint of Seafood Production From Small-Scale Fisheries

Small-scale fisheries (SSFs) and the foods they produce are extremely important, contributing 25–50% of global seafood landed for direct consumption. In some cases, SSFs provide seafoods with an exceptionally low carbon footprint, but like all food, it is important to understand the factors that regulate that footprint in the face of increasing demand and a worsening climate-ecological crisis. We utilize long-term fisheries monitoring data from Northwest Mexico to generate novel stock assessments and, subsequently, test the relationship between underlying fishery biomass and fuel intensity observed among several motorized SSFs. Using fuel data from over 4,000 individual fishing trips, in combination with estimated biomass data for 19 regional stocks, we show that the fuel footprint per kilogram of seafood increases sharply as the stock’s underlying annual biomass (B) falls below its estimated biomass at Maximum Sustainable Yield (BMSY). We find an inverse relationship between B/BMSY and fuel intensity using a test for simple correlation between the two (r= -0.44), a linear regression analysis (R2adj. = 0.17), and a mixed-effects model with gear type, year, and genus modelled as random effects. These results indicate that efforts to end overfishing, rebuild fishery stocks, and/or minimize intensive fishing practices will help to decrease the carbon emissions generated by motorized wild-catch fishing. We anticipate that this study will contribute an important “missing link” to discussions on how best to secure climate-resilient fisheries and, ideally, help SSF stakeholders garner recognition and support for SSFs in this context.

Sixty years of irrigated wheat yield increase in the Yaqui Valley of Mexico: Past drivers, prospects and sustainability

Continued global wheat yield increase (about 1.3% p.a. for 2000–2019) remains an essential condition for greater world food security. Relevant to this challenge is the rise in average farm yield (FY) of irrigated spring wheat in the Yaqui Valley of northwest Mexico from 2 to 7 t/ha between 1960 and 2019. Since the early 1950s the region has been the prime target of wheat research by the International Maize and Wheat Improvement Centre (CIMMYT) and its predecessors, research still having significant impact on wheat in the developing world, a grouping that today delivers more than half the world’s wheat. FY increase was investigated in detail by dividing the interval into three 20-year periods, correcting FY for the strong influence of inter-annual variation in January to March minimum temperature (Tmin J-M, warming lowering yield around 7%/°C) and measuring the remaining linear increase in FY (Fischer et al., 2022). Total yield increase, corrected for Tmin J-M and CO2 rise, relative to average yield in each period, was 4.17%, 0.47%, and 1.59% p.a. for 1960–79, 1980–99, and 2000–19, respectively. The breeding component, estimated by the increase in the Varietal Yield Index in farmers’ fields, rose at 0.97%, 0.49%, and 0.71% p.a., respectively. The remaining yield change (3.16, −0.02% and 0.87% p.a., respectively) comprised the net effect of improved crop management (agronomic progress) plus that of off-farm changes, together here called agronomy+ . Major changes in agronomy included: a large increase in fertiliser N use, benefitting early on from a large positive variety × N interaction; in the second period a switch to planting on raised beds and a decline in rotational diversity; and in the final period, consolidation of operational crop units and probably more skilful and timely management. Off-farm developments saw strong government financial support in the first period, but in the second period breakdown of the traditional small holder land system and withdrawal of government support. The last period saw better prices and improved access to technical advice. Breeding progress is expected to continue in the Yaqui Valley but at a slowly diminishing rate (currently 0.66% p.a.), while progress from new agronomy appears limited. Although FY gaps are small, some gap closing remains possible, and 1.2% p.a. FY progress is estimated for the next 20 years in the absence of new technologies. World wheat food security without area increase will increasingly depend on developing countries where yield gaps are generally wider and gap closing prospects better. Biophysical sustainability of the Yaqui Valley wheat system is moderately good but N management and diversity can be improved.

Epidemiological and clinical characteristics of pregnant women and neonates with COVID-19 in Northwest Mexico.

IntroductionThe SARS‐CoV‐2 virus, which causes COVID‐19, has spread quickly worldwide, causing millions of cases and thousands of deaths. Some risk factors in the general population are related to the development of severe COVID‐19 or death, but in pregnant women and neonates, the information is limited.ObjectiveTo determine the epidemiological and clinical characteristics of pregnant women and neonates diagnosed with COVID‐19 by RT–PCR and serological tests, and analyze the relationship between the influenza vaccination and COVID‐19 symptoms in infected pregnant women in Sinaloa state.MethodsWe collected samples from 116 pregnant women and 84 neonates from the Women´s Hospital of Sinaloa. They were diagnosed with COVID‐19 by RT–PCR and serological tests (IgG), and sociodemographic, clinical and laboratory parameters were recorded.ResultsA total of 11.2% (13/116) of the pregnant women were RT–PCR+, 25% (29/116) were IgG+ and 4.3% (5/116) were positive for both tests. Symptoms such as rhinorrhea (P = .04), cough (P = .02) and polypnea (P = .04) in pregnant women were related to COVID‐19, also leukocyte index was higher in pregnant women with COVID‐19 (P = .03), but the associations were lost after the Bonferroni correction. No laboratory parameters or underlying diseases were associated with COVID‐19, and most infected pregnant women had mild cases. We found an association between the influenza vaccine and less common COVID‐19 symptoms in pregnant women who were infected (P = .01). A total of 7.2% (6/84) of neonates were RT–PCR+, 35.7% (30/84) were IgG+, and there were no symptoms or underlying diseases associated with neonates who were infected. In conclusion, this work demonstrated that some symptoms were related to COVID‐19, most pregnant women and neonates had mild cases, and the influenza vaccine could decrease the severity of COVID‐19 cases in pregnant women.

Radiative transfer model inversion using high-resolution hyperspectral airborne imagery - Retrieving maize LAI to access biomass and grain yield.

Mapping crop within-field yield variability provide an essential piece of information for precision agriculture applications. Leaf Area Index (LAI) is an important parameter that describes maize growth, vegetation structure, light absorption and subsequently maize biomass and grain yield (GY). The main goal for this study was to estimate maize biomass and GY through LAI retrieved from hyperspectral aerial images using a PROSAIL model inversion and compare its performance with biomass and GY estimations through simple vegetation index approaches. This study was conducted in two separate maize fields of 12 and 20 ha located in north-west Mexico. Both fields were cultivated with the same hybrid. One field was irrigated by a linear pivot and the other by a furrow irrigation system. Ground LAI data were collected at different crop growth stages followed by maize biomass and GY at the harvesting time. Through a weekly/biweekly airborne flight campaign, a total of 19 mosaics were acquired between both fields with a micro-hyperspectral Vis-NIR imaging sensor ranging from 400 to 850 nanometres (nm) at different crop growth stages. The PROSAIL model was calibrated and validated for retrieving maize LAI by simulating maize canopy spectral reflectance based on crop-specific parameters. The model was used to retrieve LAI from both fields and to subsequently estimate maize biomass and GY. Additionally, different vegetation indices were calculated from the aerial images to also estimate maize yield and compare the indices with PROSAIL based estimations. The PROSAIL validation to retrieve LAI from hyperspectral imagery showed a R2 value of 0.5 against ground LAI with RMSE of 0.8 m2/m2. Maize biomass and GY estimation based on NDRE showed the highest accuracies, followed by retrieved LAI, GNDVI and NDVI with R2 value of 0.81, 0.73, 0.73 and 0.65 for biomass, and 0.83, 0.69, 0.73 and 0.62 for GY estimation, respectively. Furthermore, the late vegetative growth stage at V16 was found to be the best stage for maize yield prediction for all studied indices.

Eggshells assemblages and stable isotope composition in the Upper Cretaceous (Campanian) El Gallo Formation of Baja California, Mexico: Paleoenvironmental inferences

Fossil eggshells were recovered from the El Gallo Formation, Baja California, northwest Mexico, is one of the few North American Campanian continental outcrops outside the Western Interior Basin. Based on microstructure, the eggshells are referred to ornithopod (ootaxon Spheroolithus), theropods (ootaxa Prismatoolithus, two Tubercuoolithidae eggshells, Continuoolithus, Tristraguloolithus, Disperituberoolithus, Pseudogeckoolithus, Laevisoolithidae? eggshells and Enantiornithine indet.), and one crocodylomorph (cf. Neokrokolithes). While some of these ootaxa were associated with the modest, but diverse osteological record preserved there; others reveal the presence of small theropods, including as the first evidence of enantiornithine birds in the formation. Because the stable isotopic compositions of the eggshells differ from those of pedogenic carbonate nodules, we infer minimal diagenetic influence. We thus propose that the C3 plants had δ13C compositions between −27‰ and −29‰ and that warm evaporative conditions led to enriched δ18O in ingested water compared to meteoric water at least during the short period of dinosaur eggshell formation.

Notes on distribution and conservation status of three Echinocereus (Cactaceae) species from northwest Mexico

Echinocereus adustus, E. pamanesii and E. schereri are three morphological related, little known species from northwestern Mexico. In order to assess their conservation status, data on their distribution and ecological conditions were gathered from herbarium specimens, field work and databases. A data matrix of about 140 records was obtained. After curating those, eighty-eight records were kept of E. adustus subsp. adustus, E. adustus subsp. schwarzii, E. pamanesii and E. shereri. Distribution maps were generated on biogeographic provinces and ecoregions, and maps of the Area of Occupancy (AOO) and Extent of Occurrence (EOO) were prepared for each taxon. We propose to update the conservation status to Endangered for E. adustus (which has a wide distribution but very restricted occupation area) and E. schereri (restricted distribution and locally very rare), and to Near Threathened for E. pamanesii, which has a small Area of Occupancy and Extent of Occurrence but is locally common in an area not exposed to agricultural activities.