Treesearch

Aquatic environments in the Madrean Sky Islands (MSI) consist of a matrix of perennial and intermittent stream segments, seasonal ponds, and human-built cattle trough habitats that support a diverse suite of aquatic macroinvertebrates. Although environmental conditions and aquatic communities are generally distinct in lotic and lentic habitats, MSI streams are characterized by isolated perennial pools for much of the year, and thus seasonally occur as lentic environments. In this study, we compared habitat characteristics and Coleoptera and Hemiptera assemblages of stream pools with those...

Western mosquitofish Gambusia affinis has major impacts on Gila topminnow Poeciliopsis occidentalis. Thirteen years have passed since information on negative impacts has been published. I will list and discuss additional examples where mosquitofish have impacted topminnow. In addition, it appears that long-term drought has a synergistic and negative effect on this relationship. Since the last publications detailing the loss of Gila topminnow populations to mosquitofish, two natural topminnow populations have been lost in the Santa Cruz River basin: Redrock Canyon and Sharp Spring. Drought...

The Río Sonoyta in northern Sonora is an important aquatic ecosystem that is disappearing because of drought and groundwater withdrawal. Its native species are also threatened by introduced species. The only watered reach is an intermittent segment (

The Madrean Archipelago Biodiversity Assessment (MABA) of Sky Island Alliance is an ambitious project to document the distributions of all species of animals and plants in the Madrean Archipelago, focusing particularly on northeastern Sonora and northwestern Chihuahua, Mexico. The information is made available through MABA’s online database (madrean.org). The sources of these records are museum collections, herbaria, scientific literature, other databases, observations, and field notes. Many observations come from MABA expeditions to isolated mountain ranges in northeastern Sonora involving...

In 2001 Sky Island Alliance developed a citizen science program that uses track and sign identification and count surveys to monitor potential wildlife corridors throughout southeastern Arizona and southwestern New Mexico. The goal of the Wildlife Linkages Program is to protect and advocate for an interconnected landscape where wildlife, based on their ecological needs, can move easily between core habitats, the Sky Island mountain ranges. Currently, we train and engage volunteers in the monitoring of fifty 1.5-mile long transects within seven priority linkage areas; the majority of these...

The Sky Island region is a mountainous region surrounded by grasslands, deserts and intermountain valleys, located between Mexico and the United States. However, different land management and human impact can have an effect on its wildlife populations. Currently, the border wall poses an immediate threat to the survival of black bears (Ursus americanus), considered an endangered species in Mexico. Our aim was to determine the conservation status of black bears in the Sierra San Luis as affected by the border fence. We determined population size through camera traps and radio-telemetry, and...

The Sky Island region of the southwestern United States and northwestern Mexico is well-known for its diversity of mammals, including endemic species and species representing several different biogeographic provinces. Camera trap studies have provided important insight into mammalian distribution and diversity in the Sky Islands in recent years, but few studies have attempted systematic inventories of one or more mountain ranges with a repeatable, randomized study design. We surveyed medium and large terrestrial mammals of the Rincon Mountains within Saguaro National Park, and compared the...

The enduring processes of time, climate, and adaptation have sculpted the distribution of organisms we observe in the Sonoran Desert. One such organism is Morafka’s desert tortoise, Gopherus morafkai. We apply a genomic approach to identify the evolutionary processes driving diversity in this species and present preliminary findings and emerging hypotheses. The Sonoran Desert form of the tortoise exhibits a continuum of genetic similarity spanning 850 km of Sonoran desertscrub extending from Empalme, Sonora, to Kingman, Arizona. However, at the ecotone between desertscrub and foothills...

Historically, the San Bernardino Ranch has performed, as economical activities, livestock and farming, which has contributed to the deterioration of regional ecosystems. The ranch is ecologically important due to the diverse types of habitats of conservation interest such as the semi-desert grassland, the riparian vegetation, and a large ciénega, in which restoration efforts are being applied through water harvesting by gabions. Mammals are essential in the ecosystem. Knowing about the actual species that live on the different sites of the ranch tells us about the healthy state of the...

Information on bat communities, including their composition, abundance, distribution and ecology, can support management programs in protected areas, and also provide information and initiatives for the designation of new protected areas. In 2010 and 2011, monitoring was conducted in the Ajos Mountains, a sky island, that is part of the Ajos Bavispe Reserve. During this period of time, we recorded a total of eight species (Myotis californicus, Myotis auriculus, Myotis volans, Myotis thysanodes, Lasiurus cinereus, Lasiurus blossevillii, Eptesicus fuscus y Choeronycteris mexicana), in...