Aaron D FleschThe University of Arizona | UA · School of Natural Resources and the Environment
Aaron D Flesch
Doctor of Philosophy
Bi-national applied ecology and conservation biology lab based at the Desert Laboratory on Tumamoc Hill
About
74
Publications
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Introduction
I am a broadly trained ecologist focused on applied population biology, conservation, habitat selection, distributional ecology, biogeography, aridlands, applied statistics, and wildlife management. I am a research scientist in the School of Natural Resources and the Environment at University of Arizona, and resident ecologist at The Desert Laboratory on Tumamoc Hill in Tucson, Arizona.
Additional affiliations
August 2008 - December 2013
January 2003 - present
Education
August 2008 - December 2013
Publications
Publications (74)
Security infrastructure along international boundaries threatens to degrade connectivity for wildlife. To explore potential effects of a fence under construction along the U.S.-Mexico border on wildlife, we assessed movement behavior of two species with different life histories whose regional persistence may depend on transboundary movements. We us...
Strategies to conserve rare species require identifying resources that function as important habitat elements and that promote high demographic performance. Assessing the relative importance of resources, however, can be confounded by natural variation in resource availability and by the hierarchical spatial structure in which resources are organiz...
Understanding how climatic variation affects animal populations and communities is essential for addressing threats posed by climate change, especially in systems where impacts are projected to be high. We evaluated abundance dynamics of five common species of diurnal lizards over 25 years in a Sonoran Desert transition zone where precipitation dec...
Aim
To evaluate changes in breeding bird communities and assess implications for conservation.
Location
Madrean Sky Islands and northern Sierra Madre Occidental, Mexico.
Methods
I compared observations from recent fieldwork (2009–2012) with an extensive historical data set (1887–1954) and used modelling and multivariate techniques to assess spati...
In spatially structured populations, distributional dynamics are driven by the quantity, connectivity and quality of habitat. Because these drivers are rarely measured directly and simultaneously at relevant scales, information on their relative importance remains unclear. I assessed the influence of both direct and indirect measures of local habit...
Riparian zones are critical for biodiversity but have suffered widespread degradation and therefore are key targets for ecological restoration. In urban contexts, restoring riparian ecosystems can have widespread benefits but these efforts are often limited by needs to mitigate flood risks and by a lack of long-term monitoring to evaluate efficacy,...
For nearly a century, bird communities at the oasis of Quitobaquito Springs in the Sonoran Desert have attracted desert ecologists. This spring-fed oasis is among the most biologically and culturally significant sites in arid southwestern North America, but has experienced marked changes in management and is threatened by climate change, border, an...
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...
This article provides a figure summarizing the elevational distribution of each species found during an inventory conducted in 2001-2002. Details on that study were published in “Herpetofauna of the Rincon Mountains, Arizona” (Flesch et al. 2010). That paper was based on approximately 4,000 observations that resulted from surveys of randomly-locate...
Climate and landcover change can have synergistic impacts on wildlife populations, but the pervasiveness of these threats and factors that buffer them remain unclear despite important implications for conservation. I evaluated the additive and interactive effects of spatiotemporal variation in temperature, precipitation, and landcover change on ann...
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...
Broadcasting conspecific vocalizations is commonly used to survey secretive, inconspicuous, and uncommon species of birds, but information about how response behaviors vary across temporal and broad spatial gradients is limited for most species despite the importance of such data for guiding survey efforts. We assessed response patterns and detecti...
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...
This article is part of the following special collection(s): Case studies of a grassroots binational restoration collaborative in the Madrean Archipelago Ecoregion (2014-2019)
https://doi.org/10.1177/1178622120969191
Links to data, photos of the study region, and mapped results of PCA for the research paper
https://doi.org/10.1177/1178622120969191
The relationship between people and wildfire has always been paradoxical: fire is an essential ecological process and management
tool, but can also be detrimental to life and property. Consequently, fire regimes have been modified throughout history through both intentional
burning to promote benefits and active suppression to reduce risks. Reintro...
Restoring and enhancing riparian vegetation on private and communal lands in Mexico is important for biodiversity conservation given the ecological significance of these areas and the scarcity of public protected areas. To enhance riparian vegetation and wildlife habitats and train local people in restoration techniques, we implemented restoration...
The Golden Eagle (Aquila chrysaetos) is listed as threatened in Mexico but there is little information on populations in the state of Sonora. We amalgamated 121 records of the Golden Eagle in Sonora between 1892 and 2019, including 49 observations by the authors between 1997 and 2016. Observations were from all months of the year, peaked during the...
Accurate abundance estimates of plant populations are fundamental to numerous ecological questions and for conservation. Estimating population parameters for rare or cryptic plant species, however, can be challenging and thus developing and testing new methods is useful. We assessed the efficacy of distance sampling for estimating abundance and hab...
To address obligations linked to the recently approved Pima County Multi-species Conservation Plan, I identified and estimated the quality of habitat for the Cactus Ferruginous Pygmy-Owl (Glaucidium brasilianum cactorum; hereafter "pygmy-owls") and surveyed owls on Pima County Conservation Lands in south-central Arizona in 2017. To identify habitat...
Climatic flux together with anthropogenic changes in land use and land cover pose major threats to wildlife, but our understanding of their combined impacts is limited. In arid southwestern North America, ferruginous pygmy-owls (Glaucidium brasilianum) are of major conservation concern due to marked declines in abundance linked to changes in land u...
The Pima Pineapple Cactus is a federally-listed endangered species in southern Arizona that is often surveyed for compliance with federal law. The recommended survey protocol for this species (Roller method) attempts a complete census of all individuals, which is time intensive and assumes all individuals are detected during surveys. We tested a ne...
The elf owl (Micrathene whitneyi), a covered species under the Lower Colorado River (LCR) Multi-Species Conservation Program (MSCP), occurs within the LCR MSCP planning area during spring and summer, but its current distribution is much more restricted than in the past. In 2015, Great Basin Bird Observatory and University of Arizona completed the f...
The Sierra Madre Occidental and neighboring Madrean Sky Islands span a large and biologically diverse region of northwest Mexico and portions of the southwestern United States. Little is known about the abundance and habitat use of breeding birds in this region of Mexico, but such information is important for guiding conservation and management. We...
Spatial variation in resources is a fundamental driver of habitat quality but the realized value of resources at any point in space may depend on the effects of conspecifics and stochastic factors, such as weather, which vary through time. We evaluated the relative and combined effects of habitat resources, weather, and conspecifics on habitat qual...
We assessed the status and richness of birds in a remote region of northwest Mexico and provided the first description of a bird community in foothills thornscrub vegetation across the full annual cycle of seasons. Our efforts were part of a broad program to describe biodiversity and conservation value of the Northern Jaguar Reserve. This large pri...
Thirty-eight plant taxa are reported for Sonora, Mexico, for the first time. Specimens, observations, and images are deposited in herbaria and are available in the SEINet and MABA online databases.
Information on the status and habitat needs of wildlife is essential for conservation and management but often limited in remote regions with high conservation value. The Madrean Sky Islands region includes more than 40 mountain ranges located between the Sierra Madre Occidental in Mexico and the Mogollon Plateau in the U.S. These disjunct islands...
Observations of the Sierra Madrean oak Quercus viminea in ten Sky Island mountain ranges 15 to 85 km south of the Arizona and New Mexico border in Sonora and Chihuahua help define the northern and western limits of its distribution. We also discovered it in the Patagonia Mountains of southern Arizona as far north as 15.3 km from Sonora. It is sympa...
Pines are important dominants in pine-oak, pine and mixed-conifer forests across the Colorado Plateau, southern Rocky Mountains, Sierra Madre Occidental, and in the intervening Sky Islands of the U.S -Mexico borderlands. All 17 native species of pines in the Sky Islands region or their adjacent mountain mainlands reach the northern or southern marg...
Background: Some regions of the Earth sustain their own diversities through the processes of speciation and extinction. Theory predicts and data support the conclusion that the number of species (S) in such regions should attain a steady state whose value correlates with their areas (extents). Other data strongly suggest that climate plays a signif...
Survey techniques that are both reliable and efficient are necessary to accurately estimate population parameters, especially for rare species. Cactus ferruginous pygmy-owls (Glaucidium brasilianum cactorum; hereafter pygmy-owls) have declined in southwestern North America and are surveyed often to comply with federal law. We studied owl responses...
Survey techniques that are both reliable and efficient are necessary to accurately estimate population parameters, especially for rare species. Cactus ferruginous pygmy-owls (Glaucidium brasilianum cactorum; hereafter pygmy-owls) have declined in southwestern North America and are surveyed often to comply with federal law. We studied owl responses...
Estimamos la riqueza de especies, su distribución y la abundancia relativa de herpetofauna a lo largo de un gradiente de 1,800 m de elevación en las montañas Rincon durante 2001 y 2002 y comparamos los patrones de la presencia de especies en otras sierras en el sureste de Arizona. Detectamos 2,378 individuos de 40 especies durante 596 horas de mues...
Este trabajo representa una revisión y actualización de la avifauna del estado de Sonora, México.
La revisión incluyó registros de 89 artículos y reportes, 16 008 especímenes depositados en colecciones zoológicas de diferentes museos y más de doscientos setenta y ocho mil registros que corresponden a observaciones de campo y datos de anillamiento g...
Credible sightings of the Short-tailed Hawk (Buteo brachyurus) in southern Arizona, Sonora, and Southwestern Chihuahua commenced in the 1980s and since then have become increasingly numerous throughout the sky islands of Arizona, New Mexico, Sonora, and Chihuahua. In this report we summarize previously unpublished sightings and breeding records fro...
Northern Sonora, Mexico is dominated by steep elevation and rainfall gradients and a variety of vegetation communities with affinity to the Sonoran, Madrean, Sinaloan, and Chihuahuan biogeographic provinces. Despite high environmental diversity and moderate accessibility, current information on distribution and abundance of breeding landbirds is li...
Populations of cactus ferruginous pygmy-owls in northern Sonora, Mexico may aid recovery of the owl population in Arizona and contribute to long-term persistence of pygmy-owls in the Sonoran Desert. Because of the documented decline of pygmy-owls in Arizona and the proposed removal of pygmy-owls from the federal list of threatened and endangered sp...
Questions
Questions (2)
Is anyone aware of examples (successful or unsuccessful) of the use of vertebrates like raptors and snakes in ecological restoration efforts? The idea would be to erect structures that promote their use and thus increase predator abundance to reduce pressure by seed predators and grazers on vegetation response. There is recent lit. on this type of thing in crop systems (see link below), but not in replicated restoration experiments so far as I know.
I have paired samples of bird communities in 11 mountain ranges during 2 time periods and want to compare Beta sim and beta sne. Thus there are 55 pairwise values in my matrix. Is that sufficient? The results seem a little odd and I may be expecting too much from sparse data.
