Papers by Mary Mahalovich
Whitebark pine (Pinus albicaulis) forests have been declining throughout their range in western N... more Whitebark pine (Pinus albicaulis) forests have been declining throughout their range in western North America from the combined effects of mountain pine beetle (Dendroctonus ponderosae) outbreaks, fire exclusion policies, and the exotic disease white pine blister rust (Cronartium ribicola). Projected warming and drying trends in climate may exacerbate this decline; however, whitebark pine has a wide climatic tolerance because of its broad distribution coupled with high genetic diversity. A rangewide whitebark pine restoration strategy (Keane et al. 2012b) was developed recently to inform restoration efforts for whitebark pine across Federal, State, and Provincial land management agencies. This strategy, however, did not address the effects of climate change on existing whitebark pine populations and restoration efforts. In this report, we present guidelines for restoring whitebark pine under future climates using the rangewide restoration strategy structure. The information to create the guidelines came from two sources: (1) a comprehensive review of the literature and (2) a modeling experiment that simulated various climate change, management, and fire exclusion scenarios. The general guidelines presented here are to be used with the rangewide strategy to address climate change impacts for planning, designing, implementing, and evaluating fine-scale restoration activities for whitebark pine by public land management agencies.
Journal of Forestry, 1997
About the Forest Genetics Council of British Columbia The Forest Genetics Council of BC (FGC) is ... more About the Forest Genetics Council of British Columbia The Forest Genetics Council of BC (FGC) is a multi-stakeholder group representing the forest industry, Ministry of Forests and Range, Canadian Forest Service, and universities. Council's mandate is to champion forest genetic resource management in British Columbia, to oversee strategic and business planning for a cooperative provincial forest genetic resource management program, and to advise the Chief Forester on forest genetic resource management policies. About the Inland Empire Tree Improvement Cooperative Founded in 1968, the Inland Empire Tree Improvement Cooperative (IETIC) is a group of nineteen member organizations working together to apply classical plant breeding techniques to five native conifer species. Our mission is to identify and conserve genetically superior trees that can be used to produce seed for reforestation and ecosystem restoration. Our membership is a diverse mix of federal and state agencies, private companies, Indian tribes, universities, forest nurseries, private landowners and resource conservation and development councils. IETIC
Geological, climatological and ecological processes partially or entirely isolate evolutionary li... more Geological, climatological and ecological processes partially or entirely isolate evolutionary lineages within tree species. These lineages may develop adaptations to different local environmental conditions, and may eventually evolve into distinct forms or species. Isolation also can reduce adaptive genetic variation within populations of a species, potentially compromising their ability to respond to climate change. Dramatic climate changes during the Pleistocene, for example, caused species ranges to contract and fragment into isolated glacial refugia before expanding and reconnecting. The genetic signals of these processes remain in several species, and may be useful in guiding gene conservation strategies. Such within-species evolutionary differences should be considered when predicting species responses to climatic conditions. We considered within-species evolutionary differences within a climate context for ponderosa pine (Pinus ponderosa), applying results from range-wide mo...
Journal of Forestry, 2002
Relatively high levels of blister rust infection in some stands of genetically improved western w... more Relatively high levels of blister rust infection in some stands of genetically improved western white pine (Pinus monticola) raised concerns that resistance may fail under field conditions. However, surveysshow consistently lower infection and mortality in genetically improved white pine compared to unimproved stock. Restoring white pine by continued breeding for high levels of rust resistance, increased planting of resistant seedlings, and other silvicultural treatments are recommended to help alleviate forest health problems in Inland Northwest forests.
Advances in Global Change Research, 2017
Increasing air temperature, through its influence on soil moisture, is expected to cause gradual ... more Increasing air temperature, through its influence on soil moisture, is expected to cause gradual changes in the abundance and distribution of tree, shrub, and grass species throughout the Northern Rockies, with drought tolerant species becoming more competitive. The earliest changes will be at ecotones between lifeforms (e.g., upper and lower treelines). Ecological disturbance, including wildfire and insect outbreaks, will be the primary facilitator of vegetation change, and future forest landscapes may be dominated by younger age classes and smaller trees. High-elevation forests will be especially vulnerable if disturbance frequency
Frontiers in Ecology and the Environment, 2020
A nthropogenic climate change is predicted to impose an assortment of dramatic effects on society... more A nthropogenic climate change is predicted to impose an assortment of dramatic effects on society and ecosystems across the globe, prompting resource managers to look for place-based solutions to minimize associated biodiversity losses. The identification, protection, and management of climate-change refugia-generally defined as areas relatively buffered from contemporary climate change (see WebPanel 1 for a glossary of specialist terms)-has increasingly been proposed as a focus of climate adaptation actions to support the persistence of species, communities, and ecosystems, as well as sociocultural values (Keppel et al. 2015; Morelli et al. 2016). Since the refugia concept was first explored in a modern climate-change adaptation context (Ashcroft 2010; Dobrowski 2011; Keppel et al. 2012), technological and theoretical advances, as well as better recognition of practical applications (Anderson et al. 2014; Suggitt et al. 2018), have created more nuanced ways to identify and conserve these areas (Keppel et al. 2015; Morelli et al. 2016). Here, we explain not only how conservation strategies that focus on climate-change refugia increasingly incorporate ecological complexity, including issues of scale and the spectrum of climate-change vulnerability, but also how to consider objectives for climate-change refugia beyond their original static definition. The papers included in this Special Issue discuss how this burgeoning area of study is focused on improving conservation in the face of climate change. We take an inclusive view of climate-change refugia that recognizes the simultaneous importance of conservation in place ("in situ") and beyond ("ex situ") (Figure 1). Conservation of in situ refugia can help ensure some continuation of ecosystem services in the near term and preserve unique biodiversity (Keppel et al. 2015). Anticipatory planning for ex situ refugia recognizes, for example, the value of locations outside of a species' current native range that act as "stepping-stones", aiding long-term efforts to help species track their climatic niche by means of
Frontiers in Ecology and the Environment, 2020
A healthy tension exists in climate-change research between developing concepts and insights with... more A healthy tension exists in climate-change research between developing concepts and insights with broad implications and providing information that can be applied to specific locations by conservation practitioners (eg Cook et al. 2013; Meadow et al. 2015). Models and broader theory regarding the spatial patterns of biodiversity can convey important insights into how those patterns might affect species' survival in a changing environment (Thuiller et al. 2008; Franklin et al. 2017). However, conservation practitioners urgently need additional direction on what they can do on the ground to stem, or at least slow, climate-change-related biodiversity loss. While broader implications are typically analyzed at large scales, meeting the needs of conservation practitioners requires data at finer scales, with clearly delineated boundaries to confirm and refine understanding of processes implied by larger-scale analyses (Hannah et al. 2014; Keppel and Wardell-Johnson 2015). Climate-change refugia are areas relatively buffered from contemporary climate change that enable the persistence of valued physical, ecological, and sociocultural resources (Keppel et al. 2015; Morelli et al. 2016). An initial step to managing refugia for climate adaptation is identifying where they exist. This initial identification represents a spatial hypothesis constructed through various methods. Examples include comparing the current distribution of suitable habitat for a particular species with the modeled distribution of that habitat, given climate-change projections (Maher et al. 2017; Sweet et al. 2019), and mapping topographic features that buffer species from regional climate extremes (McCullough et al. 2016; Schwantes et al. 2018). However, these methods merely establish a spatial hypothesis of where climate buffering may occur, which is not an end in itself but rather a starting point toward ensuring that natural lands managers can identify, protect, and manage climate-change refugia. Morelli et al. (2016) illustrated the sequence of necessary tasks through the development of
This publication synthesizes current information on the biology, distribution, and management of ... more This publication synthesizes current information on the biology, distribution, and management of white pine blister rust (WPBR) in the Rocky Mountain Region. In this Region, WPBR occurs within the range of Rocky Mountain bristlecone pine (Pinus aristata), limber pine (P. flexilis), and whitebark pine (P. albicaulis). This disease threatens white pine species and ecosystems in some of our most treasured public and private lands, including the wildland-urban interface, Wilderness Areas, and National Parks such as Rocky Mountain National Park and Great Sand Dunes National Park and Preserve. Long-term management strategies and management options for sustaining ecosystems and preserving high-value trees are presented. This information provides forest managers with knowledge and resources needed to detect WPBR, evaluate impacted stands, and develop management strategies that are applicable in the Rocky Mountain Region.
Frontiers in Genetics, 2017
Recent population declines to the high elevation western North America foundation species whiteba... more Recent population declines to the high elevation western North America foundation species whitebark pine, have been driven by the synergistic effects of the invasive blister rust pathogen, mountain pine beetle (MPB), fire exclusion, and climate change. This has led to consideration for listing whitebark pine (WBP) as a threatened or endangered species under the Endangered Species Act, which has intensified interest in developing management strategies for maintaining and restoring the species. An important, but poorly studied, aspect of WBP restoration is the spatial variation in adaptive genetic variation and the potential of blister rust resistant strains to maintain viable populations in the future. Here, we present a simulation modeling framework to improve understanding of the long-term genetic consequences of the blister rust pathogen, the evolution of rust resistance, and scenarios of planting rust resistant genotypes of whitebark pine. We combine climate niche modeling and eco-evolutionary landscape genetics modeling to evaluate the effects of different scenarios of planting rust-resistant genotypes and impacts of wind field direction on patterns of gene flow. Planting scenarios showed different levels for local extirpation of WBP and increased population-wide blister rust resistance, suggesting that the spatial arrangement and choice of planting locations can greatly affect survival rates of whitebark pine. This study presents a preliminary, but potentially important, framework for facilitating the conservation of whitebark pine.
Restoration Ecology, 2016
Major declines of whitebark pine forests throughout western North America from the combined effec... more Major declines of whitebark pine forests throughout western North America from the combined effects of mountain pine beetle (Dendroctonus ponderosae) outbreaks, fire exclusion policies, and the exotic disease white pine blister rust (WPBR) have spurred many restoration actions. However, projected future warming and drying may further exacerbate the species' decline and possibly compromise long-term success of today's restoration activities. We evaluated successes of restoration treatments under future climate using a comprehensive landscape simulation experiment. The spatially explicit, ecological process model FireBGCv2 was used to simulate whitebark pine populations on two U.S. Northern Rocky Mountain landscapes over 95 years under two climate, three restoration, and two fire management scenarios. Major findings were that (1) whitebark pine can remain on some high mountain landscapes in a future climate albeit at lower basal areas (50% decrease), (2) restoration efforts, such as thinning and prescribed burning, are vital to ensure future whitebark pine forests, and (3) climate change impacts on whitebark pine vary by local setting. Whitebark pine restoration efforts will mostly be successful in the future but only if future populations are somewhat resistant to WPBR. Results were used to develop general guidelines that address climate change impacts for planning, designing, implementing, and evaluating fine-scale restoration activities.
American journal of botany, Jan 28, 2016
Molecular genetic evidence can help delineate taxa in species complexes that lack diagnostic morp... more Molecular genetic evidence can help delineate taxa in species complexes that lack diagnostic morphological characters. Pinus ponderosa (Pinaceae; subsection Ponderosae) is recognized as a problematic taxon: plastid phylogenies of exemplars were paraphyletic, and mitochondrial phylogeography suggested at least four subdivisions of P. ponderosa. These patterns have not been examined in the context of other Ponderosae species. We hypothesized that putative intraspecific subdivisions might each represent a separate taxon. We genotyped six highly variable plastid simple sequence repeats in 1903 individuals from 88 populations of P. ponderosa and related Ponderosae (P. arizonica, P. engelmannii, and P. jeffreyi). We used multilocus haplotype networks and discriminant analysis of principal components to test clustering of individuals into genetically and geographically meaningful taxonomic units. There are at least four distinct plastid clusters within P. ponderosa that roughly correspond ...
... several successional pathway diagrams detailed in Keane (2001) for use in modeling and planni... more ... several successional pathway diagrams detailed in Keane (2001) for use in modeling and planning ... This is the most sensitive life cycle stage because pine infection requires warm, moist ... Resistance of whitebark pine to white pine blister rust in natural populations is very low with ...
Three current issues serve as examples to convey the role of genetics in management. (1) Conseque... more Three current issues serve as examples to convey the role of genetics in management. (1) Consequences of silvicultural systems on the genetic resource of tree species are limited to one generation of study and isozyme (qualitative) data. Results of simulated data for diameter (quantitative data) over several generations, illustrate the pitfalls of working towards balanced uneven-aged silvicultural systems in northern red oak, under natural regeneration constraints and existing management direction. (2) Comparisons of section boundaries within an ecological classification system and climatic zones (homoclines) as surrogates for managing genetic resources, are of limited utility in describing patterns of genetic variation for adaptive, growth, and disease resistance traits. (3) Reporting gains and seed yields from tree improvement programs in Forest Service decision documents is recommended as means of showing consequences of 'action vs. no action' for genetic resources, thereby placing genetics in a more active role in the Agency's next round of forest planning.
Forest Ecology and Management, 2016
Abstract The overall health and persistence of whitebark pine is of international concern. Extens... more Abstract The overall health and persistence of whitebark pine is of international concern. Extensive tree mortality and loss of vigor due to the non-native pathogen white pine blister rust (Cronartium ribicola A. Dietr.), mountain pine beetle (Dendroctonus ponderosae Hopkins), altered fire regimes, and climate change endanger the existence of whitebark pine, which is an important food source (pine nuts) for several wildlife species. Prior stable isotope analysis revealed variability in intrinsic water-use efficiency and nutritional status; however, small sample sizes prohibited the identification of geo-climatic effects on those isotopes. We summarize carbon isotope discrimination (Δ13C, a measure of intrinsic water-use efficiency) and the natural abundance of δ13C, δ15N and δ34S in whitebark pine nuts in the Northern Rockies. Spatial differences in geography, soil parent material and climate (e.g., summer mean temperature, number of degree-days below 0 °C, mean annual precipitation, Hargreaves climatic moisture deficit, and the frost-free period) contributed to the low to moderate spatial resolution in selected models (R2 values ranged from 0.24 to 0.51). The importance of soil parent material in all models demonstrated whitebark pine exhibits previously unknown edaphic variation. Identification of the mechanistic drivers contributing to spatial heterogeneity in Δ13C provides an opportunity to select seed sources better suited to optimize long-term survival, vigor and cone production. Matching genetic resources to sites projected to support whitebark pine in future climates would ensure species persistence, while safeguarding an important wildlife food. Suitable wildlife habitat for projected warmer, drier climates was characterized as low values of Δ13C (
Tree Genetics & Genomes, 2015
Ponderosa pine (Pinus ponderosa) is among the most broadly distributed conifer species of western... more Ponderosa pine (Pinus ponderosa) is among the most broadly distributed conifer species of western North America, where it possesses considerable ecological, esthetic, and commercial value. It exhibits complicated patterns of morphological and genetic variation, suggesting that it may be in the process of differentiating into distinct regional lineages. A robust analysis of genetic variation across the ponderosa pine complex is necessary to ensure the effectiveness of management and conservation efforts given the species' large distribution, the existence of many isolated disjunct populations, and the potential susceptibility of some populations to climate change and other threats. We used highly polymorphic nuclear microsatellite markers and isozyme markers from 3113 trees in 104 populations to assess genetic variation and structure across the geographic range of ponderosa pine. The results reveal pervasive inbreeding and patterns of genetic diversity consistent with the hypothesis that ponderosa existed in small, as-yet-undetected Pleistocene glacial refugia north of southern Arizona and New Mexico. The substructuring of genetic variation within the species complex was consistent with its division into two varieties, with genetic clusters within varieties generally associated with latitudinal zones. The analyses indicate widespread gene flow and/or recent common ancestry among genetic clusters within varieties, but not between varieties. Isolated disjunct populations had lower genetic variation by some measures and greater genetic differentiation than main-range populations. These results should be useful for decision-making and conservation planning related to this widespread and important species.
ABSTRACT All nine species of white pines native to the U.S. or Canada are susceptible to the intr... more ABSTRACT All nine species of white pines native to the U.S. or Canada are susceptible to the introduced pathogen Cronartium ribicola. Of the six high elevation white pine species, the severe infection and mortality levels of Pinus albicaulis have been the most documented, but blister rust also impacts P. aristata, P. balfouri-ana, P. flexilis and P. strobiformis; only P. longaeva has not been documented to be infected in its natural range. Early evaluations of resistance included relatively few seedlots and demonstrated that these species have some genetic resistance to blister rust but generally less than their Eurasian relatives. Recently, more ex-tensive evaluations of these six species have begun. These recent rust tests capitalize on the methods developed from decades of prior experience by the USDA Forest Service in testing P. monti-cola and P. lambertiana. Following artificial inoculation, seedlings are evaluated for up to five years for an array of putative resistant responses including reduced number of needle spots, needle spot color, hypersensitive reaction in the needles, shedding of infected needles, presence or absence of stem infections, number of stem in-fections, latency of infection, severity of infection, bark reactions, and survival with stem infections. P. albicaulis has undergone the most extensive testing, with 650 families inoculated as of 2010. Seedling families of P. albicaulis have been tested under several inoculum densities and with different geographic sources of blister rust. Extensive work is also underway for P. aristata and P. flexilis and significant efforts have begun with P. balfouriana, P. longaeva and P. strobiformis. Initial results indicate that common resistance responses appear to be present in most species, that geographic variation in some types of resistance are present, and that some types of resistance may not be present in some species. Many more field selections are needed to build sufficient genetic diver-sity among resistant selections for each species within a breeding zone. A few field trials have been established for P. albicaulis, but additional trials for long-term verification of rust resistance from seedling screenings should be established to examine durability of rust resistance, correlated response with other adaptive traits, and response to climate change. Further examination of the many P. monticola field trials, some more than 30 years old, will help pro-vide data on durability and stability of resistance in this species and give possible insights for examining the six high elevation white pine species. Regional programs can use resistance information to designate additional parent trees for seed collection, establish seed orchards to produce greater levels of rust resistance, and pro-vide ex situ conservation of resistant individuals. The USDA Forest Service's Inland West program for P. albicaulis was the first to begin, but most regions are now active to varying extents. Based on results of seedling tests, the first resistant seedlings have been planted in several regions. Continued research on underlying re-sistance mechanisms and their inheritance, potential for greater virulence/aggressiveness in the pathogen, and molecular tools to facilitate more efficient resistant selections are needed. Recent dis-cussions of high levels of infection in the native ranges of some Asian species in China and South Korea suggest that a more viru-lent/aggressive race of C. ribicola may be present, and that a second species may exist; if so, then added precautions are needed to pre-vent importation of these pathogenic variants or other species.
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Papers by Mary Mahalovich