Cirsium Pitcheri Research Articles

Spatial Variation in Flowering Age in <i>Cirsium pitcheri</i>: Does This Imperiled Dune Thistle Hedge Its Bets?

For perennial plants, the optimal timing of flowering is a tradeoff between survivorship and fecundity, a classic example of bet-hedging. For many monocarpic perennials, there is an advantage in delaying flowering until the plant reaches a larger size and is thus capable of a higher fecundity. However, in delaying flowering, there is a risk that the plant will die before ever reproducing. Here, we investigate this fitness trade-off in the imperiled dune thistle, Cirsium pitcheri (Torr. ex Eaton) Torr. & A. Gray (Asteraceae) (Pitcher’s thistle). Using a long-term, spatially explicit demographic data set with yearly censuses, we found that C. pitcheri individuals on the foredune flowered at a younger age compared to individuals in other dune habitats. We tested two alternative hypotheses: (1) younger flowering plants were able to reach a flowering threshold size more quickly, and (2) these plants were somehow stressed, and slow growth was a signal for high likelihood of dying, resulting in early reproduction at a smaller size. Our results support the former hypothesis: plants in all areas of the dune did not differ in size the year prior to flowering, despite spatial differences in age of flowering individuals. Therefore we conclude that the foredune microenvironment where plants flowered at younger ages facilitates rapid growth and reproduction for this species and may represent optimal habitat. This result provides insight into the demographic patterns of C. pitcheri that may inform the conservation and recovery of this threatened species. Although adapted to the dynamic dune environments of the Great Lakes, C. pitcheri may be vulnerable to climate change-induced changes in its optimal foredune habitat.

Demography and threats to population growth of Cirsium pitcheri, a threatened dune plant, in Wisconsin.

Multi-year and multi-site demographic data for rare plants allow researchers to observe threats and project population growth rates and thus long-term persistence of the species, generating knowledge, which allows for effective conservation planning. Demographic studies across more than a decade are extremely rare but allow for the effects of threats to be observed and assessed within the context of interannual environmental variation. We collected demographic data on the Threatened plant Cirsium pitcheri in two sites from 2011-2022. These sites were chosen because one exhibited the presence of non-native seed predators while the other did not, and we hypothesized that we would see declines and potentially extinction of the population threatened by predation. Over the course of our study, we observed additional threats, such as human trampling and high lake levels, which led to significant erosion, sand burial, and storm damage to plants. We find high interannual variation in vital rates and population growth rates for both populations, which mask the overall effects of predation. We observed dramatic declines in plant survivorship and population growth rates in both sites in the years with high lake levels. We conclude that high lake levels, which are expected to become more frequent with climate change, pose a significant threat to all near-shore populations of C. pitcheri.

The effects of the decline of a keystone plant species on a dune community plant-pollinator network

Ecological communities are maintained through species interactions, and the resilience of species interactions is critical to the persistence of natural communities. Keystone species play outsized roles in maintaining species interaction networks, and within plant-pollinator communities are high priorities for conservation. The loss of a keystone plant from a plant-pollinator network is expected to cause changes to network structure and composition of pollinator species, with the potential to cause secondary losses of plants and pollinators. To understand how the unmanipulated decline of a keystone plant affects the structure and composition of its network, we studied the plant-pollinator interactions of a Lake Michigan dune plant community where the population of the keystone plant, Cirsium pitcheri, is in rapid decline. The network prior to C. pitcheri decline (2016) was compared to the network as C. pitcheri continued to decline (2021 and 2022) in response to habitat loss. We find evidence that the loss of C. pitcheri altered network structure such that the community may be more sensitive to perturbations. Furthermore, changes in the composition of pollinators were explained by species turnover to a greater extent than by interaction rewiring, including the loss of bumblebees. Short-term negative consequences based on the changes to network structure and composition might lead to long-term effects on the persistence of the dune community. Our study exemplifies that the decline of a keystone plant can have negative implications for conservation of a plant-pollinator community. Using an interaction network framework to assess plant-pollinator communities has potential to develop strategies for best conservation and restoration practices in habitats vulnerable to habitat loss and disturbance.

Biological control of Canada thistle (Cirsium arvense) revisited: host range of Hadroplontus litura on Cirsium species native to the Upper Midwest, USA

ABSTRACT In 1998, Hadroplontus (formerly Ceutorhynchus) litura, a stem-mining weevil, was introduced into a limited area in Minnesota for the biological control of Canada thistle, Cirsium arvense. Although showing a preference for C. arvense, initial host range testing in the 1960s indicated H. litura attacked other native Cirsium species. Before promoting or augmenting biocontrol with H. litura in Minnesota, we wanted to further define the host range of H. litura on native Cirsium species. Our objective was to determine whether H. litura could feed, oviposit and complete development on Cirsium spp. native to the Upper Midwest of the USA. In no-choice tests, female H. litura accepted all native Cirsium species for oviposition. In addition, H. litura was able to complete development to the adult stage on swamp thistle, Cirsium muticum, field thistle, Cirsium discolour, and tall thistle, Cirsium altissimum, and we confirmed the published host range test results of completed development on Flodman’s thistle, Cirsium flodmanii. These Cirsium species are within the fundamental host range of H. litura. No adults were found in development tests with Hill’s thistle, Cirsium pumilum var. hillii, a threatened or species of concern in the Upper Midwest, or Pitcher’s thistle, Cirsium pitcheri, a federally listed threatened species. Larval tunnelling was documented in C. pitcheri. We recommend that field tests be conducted, where search and host acceptance behaviour can occur under field conditions to further define the ecological host range of H. litura.

Seed size and capitulum position drive germination and dormancy responses to projected warming for the threatened dune endemic Cirsium pitcheri (Asteraceae).

Among coastal plant species at risk from rapid environmental changes is the North American Great Lakes dune endemic Cirsium pitcheri. Despite being listed as federally threatened, little is known about how C. pitcheri seed attributes influence germination and dormancy‐break patterns in the context of climate change. Following a previous work where we found differences in the number and weight of C. pitcheri seeds among capitulum positions and study sites, here we examine the effects of seed attributes (capitulum position, seed weight, and site of origin) on the proportion and timing of C. pitcheri seed germination under temperature treatments that simulate projected warming in the Great Lakes (20/10, 25/10, and 30/10°C day/night). Our results demonstrate that C. pitcheri produces diverse cohorts of seeds with seed attributes that significantly influence the timing and probability of germination over a 3‐year soil seed bank. Cirsium pitcheri seed germination proportions were highest at 20°C and decreased successively at 25 and 30°C. Seeds from terminal capitula also had higher germination proportions and took longer to germinate than those from secondary capitula. Lastly, the effect of seed weight on germination probability depended on site of origin and capitulum position, with all effects varying in size and significance over time. Ultimately, our results highlight the considerable differences in germination patterns exhibited by seeds from different capitulum positions and sites of origin and provide insight into the dormancy‐break patterns that C. pitcheri might experience under predicted temperature rise in the Great Lakes region of North America.

Temporal variation in the roles of exotic and native plant species in plant–pollinator networks

AbstractThe role of individual plant species, including those that are rare or invasive, in the structure of plant–pollinator networks will depend on how connected the plants are to pollinator species and when they flower. Plant species visited by a high diversity of pollinators that visit few other species during a particular time period are thought to provide high value to the insect community. Here, we examined the role of plant species in a plant–pollinator network across the entire flowering season and across dune and adjacent woodland habitats in Wisconsin, USA. We found strong turnover of plants, pollinators, and their interactions in time and space. Both native and exotic species play important structural roles in plant–pollinator networks. Simulations reveal that the loss of the early‐flowering rare plant, Cirsium pitcheri, would result in a disproportionate loss of pollinator species. Furthermore, the critical role that this species plays in the network is not replaced by its exotic relative, Centaurea stoebe. Our research demonstrates that consideration of temporal and spatial variability in networks allows for critical plant species to be identified within a plant–pollinator network that might otherwise be overlooked.

Effect of capitulum position and weevil infestation on seed production of threatened monocarpic perennial, Cirsium pitcheri

Cirsium pitcheri is a federally threatened, monocarpic perennial thistle species endemic to the Great Lakes region of the United States and Canada. Human habitat disturbances, lake level fluctuations and climate change have resulted in extensive declines of C. pitcheri populations. Seed predation by non-native weevil, Larinus planus, has also further exacerbated C. pitcheri population declines and reduced its projected time to extinction to less than 20 years. Given the widespread presence of L. planus throughout C. pitcheri’s range, studies that investigate its impacts are essential for understanding and predicting changes in the life histories and demographic rates of C. pitcheri populations. We present a two-year field study and common garden experiment that examine the relationship between C. pitcheri whole plant fecundity and capitulum position and assess the impacts of L. planus on C. pitcheri seed production. This study is part of an on-going population viability analysis and aims to inform C. pitcheri conservation and restoration efforts. Our results demonstrate that C. pitcheri mature seed production differs among capitulum positions and that the overall reproductive effort of C. pitcheri is reduced by L. planus. Terminal capitula being the largest and first to develop in C. pitcheri, produced the heaviest and greatest number of mature seeds across all capitulum positions. Capitula with evidence of weevil infestation, however, produced 60% fewer mature seeds and 40% fewer unfilled seeds that were also lighter than those without weevils. Evidence of weevil infestation was also primarily concentrated in secondary and tertiary capitula, which are produced at the tips of first- and second-order branches respectively. Along with information on capitulum contributions to C. pitcheri whole plant fecundity, our report presents one of the first accounts for the position-dependent oviposition of non-native weevil, L. planus, and its direct effects on C. pitcheri seed production.

An endemic plant and the plant-insect visitor network of a dune ecosystem

Network theory increasingly is used to quantify and evaluate mutualistic interactions, such as those among plants and their flower-visiting insects or pollinators. Some plant species have been shown to be important in community structure using network metrics; however, the roles of plant taxa, particularly rare species, are not well understood. Pitcher's thistle (Cirsium pitcheri), a threatened endemic of Great Lakes shorelines, flowers late-June to early-August, when other floral resources may be less abundant or unavailable. We performed 10 min insect visitor observations on all insect pollinated plants in 44–10 m by 10 m plots at Sturgeon Bay, northern lower MI, USA, during C. pitcheri flowering and recorded plant species, number of open flowers, species of insect visiting, and number of visits by insects. Pitcher's thistle received 18.2% of all 600 recorded visits, 61.1% more than the next most visited plant. Pitcher's thistle also received visits from 22 of the 59 different insect species in the network, twice as many as the next most visited plant species. Species-level network analysis metrics showed that Pitcher's thistle was most generalized, with greatest species strength, betweenness, and connectance scores of any other plant taxon, demonstrating network topological importance. Pitcher's thistle received significantly more insect visits relative to its abundance that did any other plant species. Therefore, conservation of C. pitcheri and of other rare taxa, particularly in xeric and low diversity systems, can be significant beyond species-level management and may extend to conservation of the plant-insect community.

Viability of multiple populations across the range of a species at risk: The case of Pitcher's thistle, Cirsium pitcheri, in Canada

A quantitative, probabilistic approach to species and population assessment can be used to inform a species' legal at-risk designation and help determine priorities and targets for population recovery and protection measures. To that aim, we analysed the viability of a large number of individual populations of a species across its range in Canada, we compared that viability among populations, and we assess the viability of all those populations as a whole. We used Pitcher's thistle, Cirsium pitcheri, as a case because it is listed at risk in both Canada and the United States but its actual risk of extinction remains unclear. Also, for this monocarpic plant endemic to Great Lakes dunes and beaches, there are 35 years of monitoring data available for the populations in Pukaskwa National Park on Lake Superior, and nearly 17 years of data for populations on Lake Huron. Means and variances of the annual population growth rates were computed from those time series, to estimate the cumulative distribution function for time-to-extinction, using the diffusion approximation as well as simulations. We also ran multi-population stochastic projections to estimate the risk of decline of the whole Canadian population. We found that many Pitcher's thistle populations have a high probability of either extinction or undergoing a 50% decline at some point in their future. This is due mainly to steady declines experienced by small populations. However, multi-population stochastic projections and the projected growth of many large individual populations indicate that Pitcher's thistle is likely to persist in Canada over the next 100 years, assuming past conditions continue in the future.

Insect Visitors of Cirsium pitcheri, a Threatened and Endemic Dune Species, in Relation to Annual Weather Variation

Insect Visitors of Cirsium pitcheri, a Threatened and Endemic Dune Species, in Relation to Annual Weather Variation

Nonhost neighborhood increases biocontrol weevil damage to the nontarget, federally threatened Pitcher's thistle (Cirsium pitcheri)

Studies that monitor the intensity of biocontrol insect damage on target and nontarget hosts in the field often consider the effects of neighboring vegetation that serve as acceptable alternative hosts. Whether nonhost neighboring plants can also influence damage to hosts has received less attention. The nonnative, seed-eating weevil Larinus planus has been distributed as a biocontrol agent for weedy thistles in the U.S., but also attacks native thistles including the federally threatened Cirsium pitcheri. To test the hypothesis that nonhost Ammophila breviligulata grass neighbors increase susceptibility of C. pitcheri to L. planus damage, we clipped the neighboring vegetation within a 1 m radius around focal C. pitcheri, and assessed weevil infestation in flower heads of plants with clipped or unclipped neighbors. We also examined elevational effects by surveying weevil presence along an environmental gradient and comparing infestation rates between primary and secondary dune habitats with intact neighboring vegetation. Larinus planus infestation was more prevalent at low than at high dune elevations. At low elevations, clipping neighboring vegetation surrounding C. pitcheri significantly decreased the proportion of flower heads infested by weevils. Grasses may aid L. planus dispersal to C. pitcheri hosts and/or provide a refuge from environmental stress or natural enemies. Our results highlight two factors that predict L. planus attack, as well as areas of the dune on which to focus Cirsium pitcheri management or weevil control efforts. More broadly, our results suggest that nonhost neighboring vegetation may be an important factor determining the intensity of damage by invasive and biocontrol insects.

Predicting population viability of a monocarpic perennial dune thistle using individual-based models

Plants inhabit spatially and temporally heterogeneous habitat with various landscape characteristics influencing growth, survival and reproduction. Utilizing microhabitat variables such as slope, elevation and aspect can allow for a spatially explicit approach to understand the important ecological drivers of population persistence. By applying knowledge about individual plant demographics and their response to microhabitat variables, inferences into how the entire population responds over time are made possible. We used a spatially-explicit individual based modeling (SEIBM) approach to model the population demographics and distribution of a restored population of Cirsium pitcheri in Illinois. Using regression analysis, we estimated model parameters for survival, growth and reproduction which were subsequently chosen by comparing observed and projected abundances. Projected population abundances followed the same trajectory as the observed abundances for our chosen model. Using that model, 100-year projections revealed that this Illinois Beach population has a median time to extinction (MTE) of 16 years, presenting a comparable outlook for C. pitcheri as compared to traditional matrix modeling approaches. We then analyzed how landscape characteristics influenced plant occupancy via hotspot analysis to determine optimum locations. Optimum plant habitat include those on low slopes and higher elevations. This approach presents a formal modeling exercise for using spatially explicit, individual-based models to conduct population viability analysis. By comparing this SEIBM approach to matrix modeling methods, we affirm that SEIBM are a valid tool for population viability analysis while also having the ability to include information that is spatially explicit to the habitat upon which C. pitcheri occupies.

Initial Transplant Size and Microsite Influence Transplant Survivorship and Growth of a Threatened Dune Thistle

Identifying optimal transplant size and microsite requirements are critical challenges facing restoration practitioners, and refining this information may lead to more cost effective decisions. In this study, we evaluate the effects of transplant size and microsite on restoration success of the federal threatened <i>Cirsium pitcheri</i> (Pitcher’s thistle), a monocarpic perennial restricted to shoreline sand dunes of the Great Lakes in the United States, using a ten-year dataset. Using general and generalized mixed linear models, we determined how microsite variables influenced first-year-transplant survival and subsequent growth. Our data show a higher probability of first-year survival associated with larger transplants. We also found greater plant growth at higher elevations while plants on steeper slopes are smaller the year after they are transplanted. These results have implications for restoration success, which may be maximized by regulating transplant size and selecting habitat.

Population‐specific life histories contribute to metapopulation viability

AbstractRestoration efforts can be improved by understanding how variations in life‐history traits occur within populations of the same species living in different environments. This can be done by first understanding the demographic responses of natural occurring populations. Population viability analysis continues to be useful to species management and conservation with sensitivity analysis aiding in the understanding of population dynamics. In this study, using life‐table response experiments and elasticity analyses, we investigated how population‐specific life‐history demographic responses contributed to the metapopulation viability of the Federally threatened Pitcher's thistle (Cirsium pitcheri). Specifically, we tested the following hypotheses: (1) Subpopulations occupying different environments within a metapopulation have independent demographic responses and (2) advancing succession results in a shift from a demographic response focused on growth and fecundity to one dominated by stasis. Our results showed that reintroductions had a positive contribution to the metapopulation growth rate as compared to native populations which had a negative contribution. We found no difference in succession on the contribution to metapopulation viability. In addition, we identified distinct population‐specific contributions to metapopulation viability and were able to associate specific life‐history demographic responses. For example, the positive impact of Miller High Dunes population on the metapopulation growth rate resulted from high growth contributions, whereas increased time of plant in stasis for the State Park Big Blowout population resulted in negative contributions. A greater understanding of how separate populations respond in their corresponding environment may ultimately lead to more effective management strategies aimed at reducing extinction risk. We propose the continued use of sensitivity analyses to evaluate population‐specific demographic influences on metapopulation viability. In understanding the underlying causes of the projected extinction probabilities of each population and identifying broad‐scale contributions of different populations to the metapopulation, the process of pinpointing target populations is simplified. More detailed analyses can then be applied to the target populations to increase population viability and consequently metapopulation viability. Based on our research, we suggest that the best approach to improve the overall metapopulation viability is to manage the contributions to population growth for each population separately.

Dynamics of an Invasion: The Spatial Interactions of Invasive Centaurea stoebe with Native Cirsium pitcheri and Tanacetum huronense in a Dune Environment

Abstract Centaurea stoebe is a major invader of sensitive dune habitats of the Great Lakes region in North America, home to many unique and increasingly rare species. We analyzed the beginning stages of invasion of Centaurea on a relatively isolated island in northern Lake Michigan and sought to determine whether Centaurea is negatively impacting two species of concern, Cirsium pitcheri and Tanacetum huronense. Using a nearest neighbor analysis of mapped individuals in a long term study plot, we determined Centaurea, Cirsium, and Tanacetum all have aggregated underlying spatial structures. Two-species analyses revealed highly statistically significant segregation between the species but no significant positive or negative association between the invader and either native species. Using abundance data in widespread smaller plots, we found no statistical indication that high abundances of Centaurea were correlated with low abundances of the two native species, despite marked increases in the invader. In the...

Effects of invasive knapweed (Centaurea stoebesubsp.micranthos) on a threatened native thistle (Cirsium pitcheri) vary with environment and life stage

We examined the type and magnitude of invasive plant (Centaurea stoebe subsp. micranthos (Gugler) Hayek) effects on the demographic parameters of a rare plant (Cirsium pitcheri Torr. &amp; A.Gray), using two seed addition experiments with three treatments in two dune habitats — lakeshore linear dunes and high perched dunes on Lake Michigan, USA. Treatments were near Centaurea stoebe subsp. micranthos, near a native plant, or in the open. Seedling emergence, establishment, and juvenile survivorship were significantly higher on perched dunes, with higher surface soil moisture, than on lakeshore dunes. Treatment effects varied significantly with habitat and life stage. Seedling establishment decreased near Centaurea stoebe subsp. micranthos on lakeshore dunes, but increased near any neighbor on perched dunes. However, juvenile survival was significantly lower near Centaurea stoebe. subsp. micranthos in both habitats. The probability of reaching the adult flowering stage was much lower, and occurred later, for plants near Centaurea stoebe subsp. micranthos, especially on lakeshore dunes. Thus, Centaurea stoebe subsp. micranthos had a strong negative effect on establishment, survival, and flowering of Cirsium pitcheri, but interaction intensity varied with habitat and life stage. The results suggest that coupling seed addition with watering and invasive plant removal could bolster populations of this rare endemic plant.

Population viability analysis and the effects of light availability and litter on populations of Cirsium pitcheri, a rare, monocarpic perennial of Great Lakes shorelines

An understanding of plant population dynamics in response to natural and anthropogenic influences is critical for rare species management. We present a long-term study and population viability analysis of a federally threatened monocarpic, Cirsium pitcheri, endemic to the Great Lakes, in northern Michigan. Population growth rates of C. pitcheri were highly variable; only four of the 14year-pairs studied during the 19yr study period indicated a growing population (λ>1). Elasticity analysis showed population growth was sensitive to seedling recruitment. We manipulated light and litter levels in the growth chamber to simulate natural succession or invasive plants and to determine their effects on seedlings and ultimately, population performance. The absence of shading and litter increased seedling emergence from 8% to 42%, but no simulated population had less than a 5% risk of extinction over a 25-year period. These populations are, strictly speaking, non-viable. Population viability and conservation of this species are linked to recruitment, including seedling success. Control of plant and animal invasive species and addition of greenhouse transplants to increase recruitment may help reverse population declines.

Comparison of reintroduction and enhancement effects on metapopulation viability

Metapopulation viability depends upon a balance of extinction and colonization of local habitats by a species. Mechanisms that can affect this balance include physical characteristics related to natural processes (e.g. succession) as well as anthropogenic actions. Plant restorations can help to produce favorable metapopulation dynamics and consequently increase viability; however, to date no studies confirm this is true. Population viability analysis (PVA) allows for the use of empirical data to generate theoretical future projections in the form of median time to extinction and probability of extinction. In turn, PVAs can inform and aid the development of conservation, recovery, and management plans. Pitcher's thistle (Cirsium pitcheri) is a dune endemic that exhibited metapopulation dynamics. We projected viability of three natural and two restored populations with demographic data spanning 15–23 years to determine the degree the addition of reintroduced population affects metapopulation viability. The models were validated by comparing observed and projected abundances and adjusting parameters associated with demographic and environmental stochasticity to improve model performance. Our chosen model correctly predicted yearly population abundance for 60% of the population‐years. Using that model, 50‐year projections showed that the addition of reintroductions increases metapopulation viability. The reintroduction that simulated population performance in early‐successional habitats had the maximum benefit. In situ enhancements of existing populations proved to be equally effective. This study shows that restorations can facilitate and improve metapopulation viability of species dependent on metapopulation dynamics for survival with long‐term persistence of C. pitcheri in Indiana likely to depend on continued active management.

Fungal symbiont effects on dune plant diversity depend on precipitation

Summary Historically, mutualisms have been considered to be less important than antagonisms in affecting the composition of ecological communities. In plant communities, beneficial microbes may feature as keystone mutualists in structuring community composition. Understanding the direction and magnitude of mutualist effects at the community scale may be critical for making accurate predictions on plant responses to climate change, particularly for mutualists that ameliorate climate‐induced stressors. Such mitigation could shift outcomes between mutualist‐enhanced species diversity and mutualist‐reduced diversity, depending on whether a mutualist accelerates habitat modification or competitive exclusion by its partner species. Here, we tested the relative importance and interactive effects of altered precipitation and symbiosis between an epichloid fungal endophyte and a dominant grass species for dune plant communities along the Great Lakes, USA. In 2010, we imposed field manipulations of endophyte presence in the foundation dune grass Ammophila breviligulata in combination with rainout shelters and rainfall additions. We monitored natural rates of colonization by new plant individuals over 3 years. Under the current precipitation regime, endophyte symbiosis in A. breviligulata reduced colonizing plant diversity, species richness and evenness. This effect depended on the amount of precipitation, with the symbiosis having weaker effects on plant diversity under both augmented and reduced rainfall treatments. Despite the overall negative effect of endophyte symbiosis on plant diversity, plant responses to the endophyte were species specific. A federally threatened forb, Cirsium pitcheri, increased in abundance when the symbiosis was present, regardless of precipitation regime. Endophyte symbiosis in A. breviligulata caused minor reductions in the abundance of other grass species; however, augmented precipitation benefited other grasses. Synthesis. We show that microbial mutualisms can have strong effects on community structure in a native ecosystem and that the amount of precipitation has the potential to alter how these keystone species interactions affect community composition. Predictions on future plant community structure, for both restored and native dunes, can be improved by accounting for the presence of fungal symbionts in the foundation plant species.

Climate Change Impacts on Seedling Establishment for a Threatened Endemic Thistle, Cirsium pitcheri

A study was conducted to assess the effects of predicted climate change on seedling emergence, growth, and survival for the federally listed threatened species Cirsium pitcheri in the region proximal to Chicago, Illinois, U.S.A. Three geographically distant extant populations that could potentially serve as donors to re- introduced Illinois populations were tested to determine the influence of local adaptation on seed response to climate scenarios at two future time points. For all three populations, temperature was shown to be the most critical factor impacting future growth. All populations performed worst at the 2095 temperature for four measured growth metrics: length of longest adult leaf, number of adult leaves, dry shoot mass, and dry root mass. Growth performance at the 2095 conditions did not correlate with climate familiarity but did reflect the genetic diversity of the parent population. Predicted changes in average precipitation did not produce a significant effect on any growth metric, possibly reflecting a limitation in the study conditions. Seedling emergence and survival were tied to seed mass, a trait influenced by maternal effects and correlated with the level of inbreeding depression in the parent population. These results suggest managing populations to maintain high genetic diversity could be an important factor in tolerating temperature stress associated with climate change.