Integrar la restauración activa en un plan de tratamiento de especies invasoras mediante la siembra o plantación de especies nativas que puedan suprimir competitivamente a un invasor puede ayudar a mejorar los resultados del manejo de malezas. Esto ocurre porque las plantas nativas pueden tener rasgos (métodos de acceso a recursos) que se superponen con los invasores, restringiendo a estos últimos de aprovechar recursos como la luz y el espacio. Sin embargo, la eficacia de este enfoque suele estar modificada por la disponibilidad de agua. Esto se debe a que las plantas pueden responder a cambios en la disponibilidad de agua modificando rasgos, como la densidad y tamaño de las raíces (biomasa), afectando posteriormente la magnitud en la que pueden competir con los invasores (Potts et al., 2019). Identificar rasgos de especies nativas que sean competitivas contra especies invasoras en sistemas de tierras secas con disponibilidad variable de agua puede ayudar a mejorar los resultados del control de malezas.

In Arizona and other western states, ranchers and land managers rely on thousands of miles of permanent wire fencing to manage livestock on extensive rangelands (Hayter 1939; Netz 2004). This type of fencing has improved rangeland conditions in many places by aiding in the application of grazing systems (Holecheck et al. 2011). However, wire fencing can fragment landscape connectivity, pose a risk to wildlife, and is a major financial investment. Moreover, it offers limited flexibility in adjusting pasture size, actively manipulating grazing distribution, or avoiding high-use areas or sensitive habitats within a pasture (Jakes et al. 2018).

The nature of agriculture has always been evolving with the needs of the people. As a result of the public’s concern over climate change, conservation strategies like cover cropping have been investigated to note any ecosystem services they may provide, allowing those in the industry to tally their many benefits. On a regional scale, cover crops may improve soil health and quality, additionally contributing to soil conservation; globally, cover crops may aid carbon sequestration and reduce greenhouse gas emissions. The importance of arid agriculture in this context cannot be overlooked. Many researchers, policymakers, and agricultural stakeholders in the US Desert Southwest have begun to realize that though cover crops may not be suitable for green manuring in the region due to strict water budgets, they may, however, be suitable for use as alternative forage crops to fetch additional economic gains while acting as physical barriers to prevent soil erosion and support beneficial ecosystem services ultimately improving soil health in desert agroecosystems.

From the Foreword by George B. Ruyle and Deborah J. Young: The need to reprint Arizona Range Grasses has been evident for some time. The grass family is one of the largest and most important families of flowering plants. Over half of the genera and nearly one-third of the grass species are found in Arizona. Many people enjoy the natural resources of Arizona and are interested in learning the names of the grasses. As with bird watching, an interest in grasses can greatly add to the enjoyment of nature. Additionally, ranchers and professional resource managers continue to require technical sources of information on rangelands. In this new edition, the text has been updated from the classic volume originally written by Professor R.R. Humphrey. Many changes have occurred in the scientific names. These were brought to current usage by John and Charlotte Reeder, visiting scholars at the University of Arizona (1997). These changes and their other suggestions required great expertise and much time. Additionally, at the suggestion and under the guidance of Dr. Mitch McClaran and help of Katie Meyer we have added a table of synonyms to help track these changes. Dr. McClaran also helped with the addition of growing season and origin. We wish to express our appreciation to them and to Robert Casler, who located the original line drawings for reprinting and did much to see the new edition into print. While more details are now known about the responses of grasses to defoliation, the general principles of grazing management remain similar to those Dr. Humphrey discussed in his original grass descriptions. Grazing intensity, frequency and season of use are the primary factors that determine how well grasses tolerate grazing. Moderate levels of use and periodic growing season deferment from grazing are common management prescriptions. Less consideration is given today to plant food reserves as the major control of grass regrowth following grazing. More recent research indicates that the ability to rapidly regrow after being grazed is controlled by many factors, and that this ability is critical to plant recovery following grazing. Grasses have many values beyond their use as forage, including watershed protection and natural beauty. Livestock grazing, however, continues to be a major land use in Arizona and is primarily supported by native grasses growing on rangelands. It is our hope that this book will provide a basis for the sound management of these rangeland resources and save as a tool for naturalists and others interested in grasses.

The Chiricahua leopard frog (Lithobates chiricahuensis, hereafter referred to as “CLF”) is a native frog in southern Arizona. The CLF range spans through central Arizona and south into the Altar Valley where it extends into Sonora, Mexico and east to the southwestern portion of New Mexico (1). This federally threatened species once existed in many cienegas, pools, lakes, streams, and reservoirs across southern and central Arizona. By 2011, CLF had disappeared from more than 80% of their historical locations in the U.S. (2). Their habitat is now largely limited to stock tanks, springs, and streams that are protected by local management and landowners from water loss and non-native predators such as bullfrogs. Solutions to these threats require creating and improving ideal habitat. Management approaches can be developed by investigating the factors that contribute to suitable habitat and understanding.

Seed-based ecological restoration is an approach used to revegetate damaged and disturbed habitats by spreading seed with the expectation that germination will occur and plants will become established and flourish. Although restoration can enhance the health and productivity of landscapes by reinvigorating ecosystem services both directly and indirectly, successful restoration is difficult to achieve – particularly in arid systems (Copeland et al. 2018). Germination is a well known bottleneck to plant growth that prohibits successful restoration (James at al. 2011).

Climate change, drought, human development, overgrazing, and encroachment of invasive species all threaten grasslands in southeastern Arizona and northern Mexico. These threats are leading to loss of biodiversity and degradation of these ecosystems. Native bunch grasses are especially valued for their role in reducing erosion and providing forage for wild and domestic rangeland herbivores. Mesquite (Prosopis spp.) and Lehmann lovegrass (Eragrostis lehmanniana) compete with native grasses for space and water resources, which further expedites loss of native grasses in these historical grasslands (Gornish et al. 2021).

Drought can impact ranching operations in numerous ways from directly reducing seasonally available water and forage to increasing wildfire risk and causing long-term impacts to rangelands. Monitoring weather and climate across a ranch can be a useful management tool when coupled with a detailed drought mitigation plan to anticipate impacts and trigger adaptive management decisions such as changing your grazing rotation schedule or in extreme circumstances, culling decisions (Tolleson 2016). Assessing drought conditions in the southwest U.S. is challenging because there are few long-term climate monitoring stations, especially in rural and remote areas, and monsoon rains can be very localized.

Soil health is broadly defined as the capacity of soil to support a vital living ecosystem that sustains plants, animals and humans. Soil health is related to many functions of natural and managed ecosystems such as water holding capacity, erosion control, nutrient cycling and plant growth. Soil health collectively refers to a large set of physical, chemical, and biological properties of soil systems and how they operate and function together. Accordingly, considering soil health is a rather holistic approach to evaluating soil function in terrestrial ecosystems, either in native or cultivated conditions. Soil health is quickly becoming recognized as a valuable approach of assessment of agricultural productivity and environmental well-being. Unfortunately, climate change is quickly degrading soils worldwide, rendering large swaths of previously productive landscapes unsuitable for plant and animal growth.

All parties participating in rangeland studies (i.e., monitoring, inventory, or assessment) should clearly understand strategic questions concerning "why?, what?, when?, where?, who? and how often?" data are being collected, as well as tactical ground rules that should be followed when conducting a particular sampling technique. This information should be clearly recorded either directly on data sheets or described in each report or cover sheet that accompanies the data. The information should also be catalogued and stored in a safe location in both hard copy and electronic formats where it is easily accessible by current and future observers.