Jose Raul Romo Leon

• PhD
• Professor (Full) at University of Sonora

El rápido crecimiento poblacional ha tenido como consecuencia la expansión e intensificación de zonas agrícolas en todo el mundo, con lo cual se modifican los procesos ecológicos en grandes extensiones de tierra. Al respecto, es comúnmente sabido que algunas de las tierras más propensas a la degradación/desertificación y abandono después de activid...

Legumes are essential plants in dryland ecosystems worldwide because they increase nitrogen availability, so their understanding is vital for improving knowledge and modelling in the face of climate change. This work studies the differences in resource use efficiency and their relationship with photosynthetic, photochemical, bioelemental, and stoic...

Canopy greenness is an indicator of ecosystem primary productivity, which is often limited by temperature and precipitation. Changes in vegetation greening have been reported mostly at global scales. However, we still have a poor understanding of vegetation greening patterns and drivers for major vegetation types, such as the tropical dry forest, o...

Introduction Carbon storage studies in arid and semi-arid zones are limited. The use of UAVs (unmanned aerial vehicles) has made it easier to monitor areas of interest, which is difficult with more costly techniques. Objective The aim of this study is to develop predictive models, using aerial images, to estimate aboveground carbon biomass (ABCS)...

La Reserva Jaguar del Norte es una propiedad privada ubicada en la sierra sonorense, dentro de una compleja matriz paisajística, con un amplio legado de uso ganadero. Esta región, identificada como prioritaria para la conservación, dispone de pocos datos sobre las trayectorias de cambio en la vegetación, un elemento clave para evaluar el impacto de...

Antecedentes: Las plantas en ecosistemas áridos exhiben adaptaciones a las sequías periódicas, más frecuentes e intensas por el cambio global. Conocer los atributos ecofisiológicos en las especies, ayudará a entender sus adaptaciones a las limitaciones de agua. En los ecosistemas del Noroeste de México coexisten árboles perennifolios y caducifolios...

Resumen Los refugios climáticos son sitios en los que se espera que los hábitats permanezcan relativamente protegidos de los extremos climáticos regionales y constituyen un importante foco de atención para la ciencia y la planificación de la conservación. Dentro de los paisajes multi-jurisdiccionales de alta prioridad, como las islas del cielo Madr...

Along with environmental factors, agricultural activity is one of the main drivers of change in riparian landscapes of arid regions. Some agricultural practices are considered more sustainability-oriented than others. Despite this, their use is not widespread and their effect on the provision of ecosystem services is not clearly established. Thus,...

Antecedentes: La alteración del reservorio de carbono, tiene implicación en la modificación a los ciclos biogeoquímicos.El cambio de uso y cobertura de suelo (CUCS) es uno de los principales precursores de estas alteraciones. Como consecuencia de las actividades primarias que ocurren en zonas áridas, los reservorios de carbono son continuamente mod...

Priority Marine Regions (PMR) are important areas for biodiversity conservation in the Northwest Pacific Ocean in Mexico. The oceanographic dynamics of these regions are very important to understand their variability, generate analyses, and predict climate change trends by generating an adequate management of marine resources and their ecological c...

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 Sono...

Climate refugia, or places where habitats are expected to remain relatively buffered from regional climate extremes, provide an important focus for science and conservation planning. Within high-priority, multi-jurisdictional landscapes like the Madrean sky islands of the United States and México, efforts to identify and manage climate refugia are...

Vegetation is changing rapidly in dryland ecosystems, but critical gaps remain in understanding the long‐term fluxes of carbon (C) and water. We used six years of data from two adjacent eddy covariance sites in the Sonoran Desert, a species‐rich woody C3 native shrubland and a species‐poor C4 shrubland converted to buffelgrass savanna. Although emp...

The introduction of buffel grass (Cenchrus ciliaris) to increase forage production has caused modifications in large extensions of land in the Sonoran Desert. In addition, our knowledge about the influence of climatic phenomena, such as El Niño, on vegetation productivity dynamics is limited. The present work aims to analyze the photosynthetic/ pro...

Antecedentes: Nitrógeno (N) y Fósforo (P) son los nutrientes más limitantes en plantas y su eficiencia de reabsorción sugiere estrategias de conservación. La reabsorción además afecta los cocientes estequiométricos en la hojarasca, modificando las interacciones ecológicas y los ciclos biogeoquímicos en gradientes de aridez. Hipótesis: Existirá may...

ContextRefugia are island-like habitats that are linked to environmental stability. Where topography acts as a deterministic control, microrefugia may continue to function as habitat under reduced rates of climate change. Continental island ecosystems provide propitious settings for identifying patterns of refugia at multiple scales and applying th...

We found greater variability in photosynthetic and fluorescence traits than in elemental composition (Nmass, Pmass) and stoichiometry ratios. Species in the arid site tend to have higher photosynthetic rates and photochemical integration but low WUE. In the semiarid community, leaf traits were associated to higher elemental composition (Nmass, Pmas...

Natural vegetation in arid and semi-arid environments of Northwestern Mexico has been subject to transformation due to extensive and intensive human occupation related mostly to primary activities. Keystone habitats such as riparian ecosystems are extremely sensitive to land use changes that occur in their surrounding landscape. In this study, we d...

Land cover and land-use change (LCLUC) between woody-and grass-dominated ecosystems in drylands comprise one of the largest uncertainties in the land CO 2 sink. This is especially true for the widespread transition from shrublands to grasslands/savannas caused by the establishment of exotic C 4 grass species for grazing or through biological invasi...

Diversas actividades humanas como la ganadería han transformado gran parte de la superficie terrestre, provocando cambios en todos los ecosistemas, incluyendo las áreas prioritarias para la conservación, como el caso de Sierra Libre, donde la principal actividad económica es la ganadería extensiva, cuyas acciones de manejo ocasionan la sustitución...

Herramientas de percepción remota para el estudio y monitoreo de la vegetación en zonas áridas

Ecological processes are centered to water availability in drylands; however, less known nutrient stoichiometry can help explain much of their structure and ecological interactions. Here we look to the foliar stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) of 38 dominant plant species from the Sonoran Desert, grouped in four different...

Dryland ecosystems largely control the inter-annual variability of the global carbon cycle. Unfortunately, there is a paucity of data on key biochemical parameters, such as maximum carboxylation velocity (Vcmax25) and electron transport rate (Jmax25), from species in these ecosystems which limits our capacity to model photosynthesis across ecologic...

Transformation or modification of vegetation distribution and structure in arid riparian ecosystems can lead to the loss of ecological function. Mexico has 101,500,000 ha of arid lands, however there is a general lack of information regarding how arid riparian ecosystems are being modified. To assess these modifications, we use eight sites in the S...

We analyze the importance of riparian ecosystems (RE) as critical areas for carbon storage and productivity in semi-arid regions of Northwest Mexico. We calculated the carbon storage by land cover and compared temporal trends of basal productivity (MODIS) and pre-monsoon productivity (Landsat) of RE, to other land cover types. We used land cover ma...

Riparian Zones are considered biodiversity and ecosystem services hotspots. In arid environments, these ecosystems represent key habitats, since water availability makes them unique in terms of fauna, flora and ecological processes. Simple yet powerful remote sensing techniques were used to assess how spatial and temporal land cover dynamics, and w...

Buffelgrass savanna is becoming widespread in aridland ecosystems around the world following invasion or deliberate land conversion for cattle forage. There is still a gap of information regarding functional and ecohydrological aspects such as carbon, water, and greenhouse gas exchanges in these highly productive novel ecosystems where buffelgrass...

The overexploitation of water resources in arid environments often results in abandonment of large extensions of agricultural lands, which may (1) modify phenological trends, and (2) alter the sensitivity of specific phenophases to environmental triggers. In Mexico, current governmental policies subsidize restoration efforts, to address ecological...

Our focus in this work is to analyze how land cover, identified as buffel (C. Ciliaris) grasslands, have changed from 2002 to 2011 and also analyze the difference in phenological response among the “native” cover types and the introduced buffel grasslands trough the same period of time, in protected areas, located on arid environments in the centra...

This research investigates the human impact on land-cover dynamics in arid agro-ecosystems. Our study area was La Costa de Hermosillo (northwestern Mexico), where the unregulated use of water resources has resulted in the abandonment of irrigated agricultural fields and a shift to new economic activities. Using remote sensing and ancillary datasets...

Riparian systems have become increasingly susceptible to both natural and human disturbances as cumulative pressures from changing land use and climate alter the hydrological regimes. This article introduces a landscape dynamics monitoring protocol that incorporates riparian structural classes into the land-cover classification scheme and examines...

Buffel savannas have been an important landscape on cattle grazing ranches in Sonora over the past 50 years or more. Changes in land use result in biodiversity changes that may produce ecosystem functional changes; however, these are less well documented. Although fire driven processes have been proposed for Buffel savannas, this is not generally t...

Post-fire vegetation response is influenced by the interaction of natural and anthropogenic factors such as topography, climate, vegetation type and restoration practices. Previous research has analyzed the relationship of some of these factors to vegetation response, but few have taken into account the effects of pre-fire restoration practices. We...

Prairie dog is a keystone species throughout the habitat where it occurs, but its populations have declined about 98% in the last century. This species has been considered of international importance for the United States of America, Canada, and Mexico. Only two populations are recorded for Mexico, and the westernmost (isolated by Sierra Madre Occi...

"December 2006." Includes bibliographical references (leaves 92-96 ) and abstract. Thesis (M.S.) -- Northern Arizona University, 2006.