Oscar G. Gutierrez-Ruacho’s research while affiliated with Universidad Estatal de Sonora and other places

Aerobiological studies are still scarce in northwestern Mexico where allergenic pollen have great impacts on health. Current global pollution and climate change problems are closely related to many allergic diseases, enhancing the need to continue researching these issues and improve life quality. This study provides the first Pollen Calendar for Hermosillo, Sonora, México. Airborne pollen were continuously collected for 5 years (2015–2019). The standardized methodology with a Hirst-type spore trap proposed for global aerobiological studies was used. Weather data were also taken from a station located in the city and used to explore correlations between climate and airborne pollen concentrations in different seasons. The most important pollen taxa recorded in air belongs to herbaceous pollen, such as Poaceae, Ambrosia, Asteraceae, Chenopodiaceae-Amaranthaceae, and some shrub trees typical of this arid region, such as Nyctaginaceae, Prosopis, Parkinsonia, and Fabaceae. The most critical herbaceous pollen related to allergies have a long mean pollen season throughout the years, and the most critical periods with high pollen concentration in air occur in two seasons, spring (March–April) and summer–fall (August–October). In these 5 years, the correlation analyses for these two peaks indicate that a link exists between pollen in the air and decreases in precipitation and temperatures, and an increase in relative humidity. An inter-annual variability in pollen concentrations was recorded related to different weather conditions. Although pollen calendars are location-specific, they are useful for future research on biological air quality scenarios in different cities. Using this standardized method for other regions can provide pollen calendars that have been proven clinically important in allergic disease management worldwide.

The persistence of a species throughout its geographic range requires dispersal among its populations. The study of dispersal is particularly relevant for species whose geographic range has contracted, such as the endangered Northern Aplomado Falcon (Falco femoralis septentrionalis). We used Argos 5-g PTT-100 satellite transmitters to determine the movements of two wild Chihuahuan Desert Aplomado Falcons (one female and one male) from fledging to breeding (male), or transmitter failure (female), at 1062 d and 439 d of age, respectively. Both falcons dispersed from their natal territories 2-3 mo after fledging. These falcons then wandered between activity centers near historic breeding territories and some territories recently converted to farmlands. These two falcons also explored areas outside known breeding areas via some long-distance movements to areas of potential breeding habitat being converted to farmland. In 2 yr, movements of the male covered 7412 sq. km. This falcon nested unsuccessfully with an unbanded female in a vacant breeding territory 15 km from his natal site. His nesting attempt the following year yielded two fledglings. While a breeding bird, the male falcon had a home range of 200 sq. km. For 17 mo, the female falcon wandered through an area of 12,136 sq. km. The farthest distance she traveled from her nest site prior to transmitter failure was 154 km.

We conducted the first study of air pollen and fungal spores for Hermosillo, Sonora, where the human population is exposed to high temperatures and high levels of dust and suffers from diseases related to air quality. We sampled pollen and fungal spores daily in the air during 2016 using a volumetric spore trap Hirst-type sampler. We used simple linear correlation to investigate the association between pollen and spore counts and daily weather conditions. We found an Annual Pollen Integral of 16,243 pollen day/m 3 and an Annual Spore Integral higher 222,365 spore day/m 3. We identified 32 pollen taxa and 15 different spores. We found two periods of higher pollen and spore concentrations: March to May and August to October, the latter was the most severe. Spore and pollen concentrations in the air increased at higher temperature and higher relative humidity but decreased at higher precipitation. We detected negative impacts during summer and fall on population health, with 13,454 cases of people who presented diseases related to allergies. A peak in allergies is centered during October and correlates well with our peaks in pollen and spore concentrations; it seems that pollen of Poaceae is the one that generates most effects in allergic people. ARTICLE HISTORY

We determined the effect of the seasonal distribution of summer rainfall and associated seasonal changes in vegetation on the timing of reproduction and reproductive success of the Rufous-winged Sparrow (Peucaea carpalis) in the plains of central Sonora, Mexico, and influence of exotic buffelgrass (Pennisetum ciliare). We monitored 302 nests twice weekly from early July to early October of 2012-2014. We fitted Bayesian logistic-exposure models for nest survival data using covariables year, nest stage, date, normalized difference vegetation index, shrub cover, buffelgrass cover, and nest height. Mean daily nest survival probability equaled 95.9% (95% CRI 95.1%-96.1%), with nest survival probability averaging 36.3% (95% CRI 30.2%-42.5%) during the nesting season.We found evidence that daily nest survival probability differed between nest stages but variation in environmental explanatory variables among nests did not explain variation in daily nest survival probability, despite suggestive evidence of a positive association between NDVI and daily nest survival probability. Daily nest survival probability seemed unaffected by the habitat alteration in buffelgrass prairies, suggesting that the Rufous-winged Sparrow may be resilient to habitat transformation in the center of its distribution.

A unique relictual population of Fouquieria columnaris is located in Sonora, along a 45-km strip of land encompassing Punta Cirio in the Sonoran Desert. The interaction of plants with microorganisms is an important adaptation to survival in desertic areas. The present study reports the abundance of bacteria, actinobacteria, and filamentous and arbuscular mycorrhizal fungi (AMF) in the rhizosphere of F. columnaris at Punta Cirio. Also, the genetic variability of F. columnaris was analyzed using amplied fragment length polymorphism markers. Bacteria and fungi in 27 soil samples from the rhizosphere of F. columnaris at 3 hills with low, medium, and high elevations were analyzed. The total bacterial, actinobacterial, and filamentous fungal counts did not differ among sites or elevations; no interaction between site and elevation was found. Nitrogen-fixing bacteria varied according to site but not elevation, whereas phosphorus-solubilizing bacteria were undetected. Filamentous fungi were dominated by Aspergillus spp. (48%) and Penicillium spp. (28%), which together represented 76% of the total average colony-forming units. The spore density of AMF ranged from 109 to 245 per 100 g of soil, and 65 to 80% of roots were colonized by hyphae, vesicles, or arbuscles of AMF. The DNA analysis generated an average similarity coefficient of 0.89, which could indicate high genetic homogeneity within the evaluated F. columnaris population. © 2018 Universidad Nacional Autonoma de Mexico. All rights reserved.

In this study, we review the main contributions of palynology with emphasis on the study of past communities and its relationship to climate variability. The study of pollen and spores in sediments allows us to recreate the landscape, acting as a window to understand plant communities’ dynamics and climate through time. This aspect is of vital importance today to understand the response of vegetation to the current and future climate change. The results of these studies assist in decision making processes for species’ management and conservation, also allowing the calibration of climate and vegetation models. Furthermore, the study of pollen sequences in time allows us to track human activities in study sites, as there are indicators, such as corn pollen, of agricultural activities in the region. In this case, we review the main results found for northwest Mexico, specifically in the region of Yécora, Sonora and surroundings. In this region, there have been conducted studies of the pollen content in sediments at 4 sites distributed between 1,500 and about 2,000 m altitude. These sites record the history of changes in vegetation and climate during the Holocene indicating a wide distribution of pine forests 10.000 years ago, a shift towards more temperate pine-oak forests 6,000 years ago and a general decline of forests during the last 2,000 years, which coincides with the record of human activities in the region.

In arid regions, spring-fed habitats are frequently the only year-round source of surface water and are essential habitats for aquatic organisms and primary water sources for terrestrial animals and human settlements. While these habitats have been relatively well-studied in some regions, those of the southern Sonoran Desert have received little attention. In 2008 and 2009, we documented the biodiversity of aquatic animals at 19 sites across three arid mountain ranges in Sonora, Mexico, characterized macrohabitat types, examined seasonal variation in aquatic invertebrate communities, and explored the effects of an exotic fish (tilapia) on native communities. We documented [220 aquatic animal species, including several new species and range extensions for others. Macrohabitat type (oasis, tinaja, riffle, and seep) was more important than geographic location in structuring aquatic invertebrate communities at the scale of our study area (*9,000 km 2). We found little evidence of predictable seasonal variation in invertebrate communities, despite dramatic hurricane-induced flooding. Aquatic vertebrates were not diverse across the study region (4 amphibian species and 2 species each of fishes and reptiles), but were often locally abundant. Presence of non-native tilapia at one site was associated with reduced abundances of native leopard frogs and reduced richness and density of native aquatic invertebrates. The most pressing aquatic habitat conservation concerns in the region, as in other deserts, are groundwater withdrawal, unmanaged recreational visitation, and the introduction of exotic species. Spring-fed habitats around the world have been called hotspots of freshwater biodiversity, and those of the Sonoran Desert are no exception.

For a sustainable management of grazing lands, is necessary to know the strategy of nature to sustain the grassland, in consequence, the management schemes must be based in programs related to an environmental characterization and adequate monitoring. With the aim to develop a tool to support the diagnosis of grasslands, we hereby propose the application of the Hydro-Environmental Availability Index (HEAI), with scale from 0 to 10. According to the application of HEAI in 36 localities of Sonora, Mexico, five of them (13.9 %) fluctuated from 0 to 2.5, in consequence, their grasslands are highly vulnerable to drought, with very low possibilities for management. Twenty (55.6 %) oscillated from 2.5 to 5, suggesting a management with severe restrictions. Eleven (30.5 %) fluctuated from 5 to 7.5, proposing a sustainable management with adequate rotations and preventions during a drought, and none of localities reached values for HEAI > 7.5, high potential for sustainable management, with appropriate rotations. It must be considered that the actions to prevent the effects of overgrazing, not always are enough to mitigate the overwhelming consequences of droughts, which are exacerbated by climate change.

For a sustainable management of grazing lands, is necessary to know the strategy of nature to sustain the grassland, in consequence, the management schemes must be based in programs related to an environmental characterization and adequate monitoring. With the aim to develop a tool to support the diagnosis of grasslands, we hereby propose the application of the Hydro-Environmental Availability Index (HEAI), with scale from 0 to 10. According to the application of HEAI in 36 localities of Sonora, Mexico, five of them (13.9 %) fluctuated from 0 to 2.5, in consequence, their grasslands are highly vulnerable to drought, with very low possibilities for management. Twenty (55.6 %) oscillated from 2.5 to 5, suggesting a management with severe restrictions. Eleven (30.5 %) fluctuated from 5 to 7.5, proposing a sustainable management with adequate rotations and preventions during a drought, and none of localities reached values for HEAI < 7.5, high potential for sustainable management, with appropriate rotations. It must be considered that the actions to prevent the effects of overgrazing, not always are enough to mitigate the overwhelming consequences of droughts, which are exacerbated by climate change.

While distributions of aquatic insects are fairly well known in the southwestern United States, relatively few surveys have been conducted in northwestern Mexico. We report new collections of species of aquatic Heteroptera in the region, which extend the known range of several species by hundreds of kilometers, including the first record of Graptocorixa emburyi in the United States, and help show that disjunct distributions of other species are more continuous than previously thought. RESUMEN—Aunque la distribucíon de insectos acuáticos en el suroeste de los Estados Unidos es bien conocida, se ha hecho poca investigací on sobré estos en el noroeste de México. Presentamos nuevos registros de especies acuáticas de Heteroptera en la regíon, lo cual amplía el rango de distribucíon de varias especies por cientos de kilómetros, incluyendo el primer registro de Graptocorixa emburyi para los Estados Unidos, y contribuye a llenar huecos grandes de distribucíon de otras especies.