Publications by authors named "Benjamin N Sacks"

Specialist species in alpine ecosystems may be increasingly threatened by climate-driven habitat loss and encroachment by generalist competitors. Ecological theory predicts that niche differentiation through dietary specialisation can facilitate coexistence with generalist competitors. We quantified dietary overlap between a high-elevation specialist, the Sierra Nevada red fox (SNRF; Vulpes vulpes necator) and a widespread generalist, the coyote (Canis latrans), as well as other sympatric carnivores.

View Article and Find Full Text PDF

A few iconic examples have proven the value of facilitated gene flow for counteracting inbreeding depression and staving off extinction; yet, the practice is often not implemented for fear of causing outbreeding depression. Using genomic sequencing, climatic niche modeling, and demographic reconstruction, we sought to assess the risks and benefits of using translocations as a tool for recovery of endangered montane red fox (Vulpes vulpes) populations in the western United States. We demonstrated elevated inbreeding and homozygosity of deleterious alleles across all populations, but especially those isolated in the Cascade and Sierra Nevada ranges.

View Article and Find Full Text PDF

Human-facilitated introductions of nonnative populations can lead to secondary contact between allopatric lineages, resulting in lineage homogenisation or the formation of stable hybrid zones maintained by reproductive barriers. We investigated patterns of gene flow between the native Sacramento Valley red fox (Vulpes vulpes patwin) and introduced conspecifics of captive-bred origin in California's Central Valley. Considering their recent divergence (20-70 kya), we hypothesised that any observed barriers to gene flow were primarily driven by pre-zygotic (e.

View Article and Find Full Text PDF

The first record of captive-bred red foxes (Vulpes vulpes) dates to 1896 when a breeding enterprise emerged in the provinces of Atlantic Canada. Because its domestication happened during recent history, the red fox offers a unique opportunity to examine the genetic diversity of an emerging domesticated species in the context of documented historical and economic influences. In particular, the historical record suggests that North American and Eurasian farm-bred populations likely experienced different demographic trajectories.

View Article and Find Full Text PDF

Ancestral Coast Salish societies in the Pacific Northwest kept long-haired "woolly dogs" that were bred and cared for over millennia. However, the dog wool-weaving tradition declined during the 19th century, and the population was lost. In this study, we analyzed genomic and isotopic data from a preserved woolly dog pelt from "Mutton," collected in 1859.

View Article and Find Full Text PDF

Increasing impacts of wildfire on arid regions of the world fuelled by climate change highlight the need to better understand how natural communities respond to fire. We took advantage of a large (1660-km ) wildfire that erupted in northern California during an in-progress study of black-tailed deer (Odocoileus hemionus columbianus) to investigate deer use of and diets within burned and unburned habitats before and after the fire. We compared deer diet breadth to predictions of optimal foraging theory, the niche variation hypothesis, and opportunistic (i.

View Article and Find Full Text PDF
Article Synopsis
  • The Holarctic lineage of gray wolves is the most studied and widespread, especially in North America and Europe, while less is known about the Tibetan and Indian wolf lineages in southern Asia.
  • Researchers conducted mitochondrial and genome-wide sequencing of wolves from Pakistan and Kyrgyzstan to investigate the contact zones between these lineages.
  • Their findings revealed significant interaction between the Holarctic and Indian wolves in Pakistan, and emphasized the conservation importance of Pakistani wolf populations, particularly those in endangered regions like Sindh and Southern Punjab.
View Article and Find Full Text PDF
Article Synopsis
  • Secondary contact zones between deeply divergent lineages, like North American grey foxes, offer insights into the speciation process.
  • The eastern and western lineages of grey foxes diverged around 1 million years ago and currently hybridize in the southern Great Plains, suggesting they recently came into contact after a long period of separation.
  • Genetic analyses revealed two historical pulses of admixture, with the eastern lineage experiencing a significant decline in population size and habitat changes during isolation, followed by an expansion in suitable habitat that allowed for increased hybridization.
View Article and Find Full Text PDF

Carnivores play critical roles in ecosystems, yet many species are declining worldwide. The Sierra Nevada Red Fox (; SNRF) is a rare and endangered subspecies of red fox limited to upper montane forests, subalpine, and alpine environments of California and Oregon, United States. Having experienced significant distribution contractions and population declines in the last century, the subspecies is listed as at-risk by relevant federal and state agencies.

View Article and Find Full Text PDF
Article Synopsis
  • The gray fox lineage is ancient and split from other canids, primarily found in the Americas.
  • Mitochondrial and nuclear DNA analyses show that eastern and western gray foxes diverged around the mid-Pleistocene and meet in the southern Great Plains, where they remain genetically distinct.
  • Admixture is low, indicating either recent contact or barriers between the lineages, suggesting significant evolutionary divergence between eastern and western gray foxes.
View Article and Find Full Text PDF
Article Synopsis
  • The study examines the population structure of gray foxes and the evolutionary origins of the island fox using mitochondrial sequences and nuclear microsatellites.
  • The island fox is believed to have appeared on the Channel Islands between 6,000 and 13,000 years ago, but its exact lineage—whether directly from mainland gray foxes or a distinct now-extinct population—is still debated.
  • Genetic analysis shows that island foxes are monophyletic and genetically distinct from western gray foxes, with evidence of historical gene flow and admixture in some populations.
View Article and Find Full Text PDF

Before Europeans colonized North America, a uniquely American wolf roamed the eastern forests of southern Canada to Florida and west to the Great Plains. Known today as "red wolf" (Canis rufus) in the south and "eastern wolf" (Canis lycaon) in the north, evidence suggests that these indigenous forest wolves shared a common evolutionary history until only a few centuries ago when they were extirpated from the intervening majority of their historical range. While the eastern wolf persists today primarily as a small population in Algonquin Provincial Park, Canada, the red wolf was ostensibly driven from its last stronghold in gulf-coastal Louisiana and Texas by 1980.

View Article and Find Full Text PDF

The salt marsh harvest mouse (; RERA) is an endangered species endemic to the coastal wetlands of the San Francisco Estuary, California. RERA are specialized to saline coastal wetlands, and their historical range has been severely impacted by landscape conversion and the introduction of non-native plant and rodent species. A better understanding of their diet is needed to assess habitat quality, particularly in relation to potential competitors.

View Article and Find Full Text PDF

As anthropogenic disturbances continue to drive habitat loss and range contractions, the maintenance of evolutionary processes will increasingly require targeting measures to the population level, even for common and widespread species. Doing so requires detailed knowledge of population genetic structure, both to identify populations of conservation need and value, as well as to evaluate suitability of potential donor populations. We conducted a range-wide analysis of the genetic structure of red foxes in the contiguous western U.

View Article and Find Full Text PDF

Domestic dogs (Canis lupus familiaris) are the most variable-sized mammalian species on Earth, displaying a 40-fold size difference between breeds. Although dogs of variable size are found in the archeological record, the most dramatic shifts in body size are the result of selection over the last two centuries, as dog breeders selected and propagated phenotypic extremes within closed breeding populations. Analyses of over 200 domestic breeds have identified approximately 20 body size genes regulating insulin processing, fatty acid metabolism, TGFβ signaling, and skeletal formation.

View Article and Find Full Text PDF
Article Synopsis
  • Carnivores like the red fox show weak genetic structure across large areas, complicating the tracking of their post-glacial movement patterns.
  • This study utilized genome-wide data from 524 red foxes to explore variations and genetic mixing across European populations, revealing important refugial areas and endemism, particularly in Spain.
  • The research also tested various recolonization scenarios post-Last Glacial Maximum, concluding that natural colonization of Ireland was more plausible than human introduction, suggesting a richer mammalian community on the island during the early post-glacial era.
View Article and Find Full Text PDF

The grey wolf (Canis lupus) expanded its range across Holarctic regions during the late Pleistocene. Consequently, most grey wolves share recent (<100,000 years ago) maternal origins corresponding to a widespread Holarctic clade. However, two deeply divergent (200,000-700,000 years ago) mitochondrial clades are restricted, respectively, to the Indian subcontinent and the Tibetan Plateau, where remaining wolves are endangered.

View Article and Find Full Text PDF

The red wolf (Canis rufus) of the eastern US was driven to near-extinction by colonial-era persecution and habitat conversion, which facilitated coyote (C. latrans) range expansion and widespread hybridization with red wolves. The observation of some grey wolf (C.

View Article and Find Full Text PDF

The red fox () has a wide global distribution with many ecotypes and has been bred in captivity for various traits, making it a useful evolutionary model system. The Y chromosome represents one of the most informative markers of phylogeography, yet it has not been well-studied in the red fox due to a lack of the necessary genomic resources. We used a target capture approach to sequence a portion of the red fox Y chromosome in a geographically diverse red fox sample, along with other canid species, to develop single nucleotide polymorphism (SNP) markers, 13 of which we validated for use in subsequent studies.

View Article and Find Full Text PDF

The mitogenome of Prometheomys schaposchnikowi was characterized for the first time as a circular DNA molecule (16.284 bp), containing 37 coding and 2 non-coding regions. In the mitogenome, ND6 and 8 tRNA genes were encoded on the light chain, while 12 PCGs, 14 tRNAs, 2 rRNAs, D-loop and O were encoded on the heavy chain.

View Article and Find Full Text PDF

The complex topography, climate, and geological history of Western North America have shaped contemporary patterns of biodiversity and species distributions in the region. Pacific martens (Martes caurina) are distributed along the northern Pacific Coast of North America with disjunct populations found throughout the Northwestern Forested Mountains and Marine West Coast Forest ecoregions of the West Coast. Martes in this region have been classified into subspecies; however, the subspecific designation has been extensively debated.

View Article and Find Full Text PDF

Domestic dogs have been central to life in the North American Arctic for millennia. The ancestors of the Inuit were the first to introduce the widespread usage of dog sledge transportation technology to the Americas, but whether the Inuit adopted local Palaeo-Inuit dogs or introduced a new dog population to the region remains unknown. To test these hypotheses, we generated mitochondrial DNA and geometric morphometric data of skull and dental elements from a total of 922 North American Arctic dogs and wolves spanning over 4500 years.

View Article and Find Full Text PDF

A recent study demonstrated that British red foxes introduced to the mid-Atlantic coastal plain (ACP) of the eastern United States during the late 18th century successfully interbred with indigenous American red foxes despite half a million year's divergence. However, a large disparity in frequency of European mitochondria (27%) versus Y chromosomes (1%) left unclear the magnitude of genetic exchange. We sought to quantify genomic introgression using 35 autosomal and 5 X-chromosome ancestry-informative markers (AIMs) in conjunction with diagnostic Y chromosome single nucleotide polymorphism (Y-SNP) markers to characterize the modern state of red foxes in the eastern United States and to gain insight into the potential role of reproductive barriers.

View Article and Find Full Text PDF

Genetic factors in the decline of small populations are extremely difficult to study in nature. We leveraged a natural experiment to investigate evidence of inbreeding depression and genetic rescue in a remnant population of subalpine-specialized Sierra Nevada red foxes (Vulpes vulpes necator) using noninvasive genetic monitoring during 2010-2017. Only 7 individuals were detected in the first 2 years.

View Article and Find Full Text PDF

From a conservation management perspective it is important to understand how genetic diversity is partitioned across a species' range, including 1) identification of evolutionarily distinct units versus those recently isolated through anthropogenic activities and 2) the relative genetic contributions among components of fragmented (meta)populations. To address these questions, we investigated the phylogeography and metapopulation structure among relict populations of the endangered giant kangaroo rat (Dipodomys ingens) in the highly altered San Joaquin Desert Ecosystem. This keystone species underwent a ~97% range reduction over the past century, resulting in a current range that is highly fragmented, with 2 dominant northern and southern populations occurring 150 km apart.

View Article and Find Full Text PDF