Publication Search Results

Search Results

Showing 1-15 of about 15 results.
Long-Term Impacts of Invasive Insects and Pathogens on Composition, Biomass, and Diversity of Forests in Virginia's Blue Ridge MountainsAnderson-Teixeira, Kristina J.Herrmann, ValentineCass, Wendy B.Williams, Alan B.Paull, Stephen J.Gonzalez-Akre, Erika B.Helcoski, RyanTepley, Alan J.Bourg, Norman A.Cosma, Christopher T.Ferson, Abigail E.Kittle, CarolineMeakem, VictoriaMcGregor, Ian R.Prestipino, Maya N.Scott, Michael K.Terrell, Alyssa R.Alonso, AlfonsoDallmeier, FranciscoMcShea, William J.2020DOI: info:10.1007/s10021-020-00503-wEcosystems1432-9840
Anderson-Teixeira, Kristina J., Herrmann, Valentine, Cass, Wendy B., Williams, Alan B., Paull, Stephen J., Gonzalez-Akre, Erika B., Helcoski, Ryan, Tepley, Alan J., Bourg, Norman A., Cosma, Christopher T., Ferson, Abigail E., Kittle, Caroline, Meakem, Victoria, McGregor, Ian R., Prestipino, Maya N., Scott, Michael K., Terrell, Alyssa R., Alonso, Alfonso, Dallmeier, Francisco, and McShea, William J. 2020. "Long-Term Impacts of Invasive Insects and Pathogens on Composition, Biomass, and Diversity of Forests in Virginia's Blue Ridge Mountains." Ecosystems https://doi.org/10.1007/s10021-020-00503-w
ID: 155476
Type: article
Authors: Anderson-Teixeira, Kristina J.; Herrmann, Valentine; Cass, Wendy B.; Williams, Alan B.; Paull, Stephen J.; Gonzalez-Akre, Erika B.; Helcoski, Ryan; Tepley, Alan J.; Bourg, Norman A.; Cosma, Christopher T.; Ferson, Abigail E.; Kittle, Caroline; Meakem, Victoria; McGregor, Ian R.; Prestipino, Maya N.; Scott, Michael K.; Terrell, Alyssa R.; Alonso, Alfonso; Dallmeier, Francisco; McShea, William J.
Keywords: NZP; STRI
Abstract: Exotic forest insects and pathogens (EFIP) have become regular features of temperate forest ecosystems, yet we lack a long-term perspective on their net impacts on tree mortality, carbon sequestration, and tree species diversity. Here, we analyze 3 decades (1987-2019) of forest monitoring data from the Blue Ridge Mountains ecoregion in eastern North America, including 67 plots totaling 29.4 ha, along with a historical survey from 1939. Over the past century, EFIP substantially affected at least eight tree genera. Tree host taxa had anomalously high mortality rates (>= 6% year(-1) from 2008 to 2019 vs 1.4% year(-1) for less-impacted taxa). Following the arrival of EFIP, affected taxa declined in abundance (- 25 to - 100%) and live aboveground biomass (AGB; - 13 to - 100%) within our monitoring plots. We estimate that EFIP were responsible for 21-29% of ecosystem AGB loss through mortality (- 87 g m(-2) year(-1)) from 1991 to 2013 across 66 sites. Over a century, net AGB loss among affected species totaled roughly 6.6-10 kg m(-2). The affected host taxa accounted for 23-29% of genera losses at the plot scale, with mixed net effects on alpha-diversity. Several taxa were lost from our monitoring plots but not completely extirpated from the region. Despite these losses, both total AGB and alpha-diversity were largely recovered through increases in sympatric genera. These results indicate that EFIP have been an important force shaping forest composition, carbon cycling, and diversity. At the same time, less-affected taxa in these relatively diverse temperate forests have conferred substantial resilience with regard to biomass and alpha-diversity.
Tree height and leaf drought tolerance traits shape growth responses across droughts in a temperate broadleaf forestMcGregor, Ian R.Helcoski, RyanKunert, NorbertTepley, Alan J.Gonzalez‐Akre, Erika B.Herrmann, ValentineZailaa, JosephStovall, Atticus E. L.Bourg, Norman A.McShea, William J.Pederson, NeilSack, LawrenAnderson‐Teixeira, Kristina J.2020DOI: info:10.1111/nph.16996New Phytologist0028-646X
McGregor, Ian R., Helcoski, Ryan, Kunert, Norbert, Tepley, Alan J., Gonzalez‐Akre, Erika B., Herrmann, Valentine, Zailaa, Joseph, Stovall, Atticus E. L., Bourg, Norman A., McShea, William J., Pederson, Neil, Sack, Lawren, and Anderson‐Teixeira, Kristina J. 2020. "Tree height and leaf drought tolerance traits shape growth responses across droughts in a temperate broadleaf forest." New Phytologist https://doi.org/10.1111/nph.16996
ID: 157275
Type: article
Authors: McGregor, Ian R.; Helcoski, Ryan; Kunert, Norbert; Tepley, Alan J.; Gonzalez‐Akre, Erika B.; Herrmann, Valentine; Zailaa, Joseph; Stovall, Atticus E. L.; Bourg, Norman A.; McShea, William J.; Pederson, Neil; Sack, Lawren; Anderson‐Teixeira, Kristina J.
Keywords: NZP; STRI
No significant increase in tree mortality following coring in a temperate hardwood forestHelcoski, RyanTepley, Alan J.McGarvey, Jennifer C.Gonzalez-Akre, ErikaMeakem, VictoriaThompson, Jonathan R.Anderson-Teixeira, Kristina J.2019DOI: info:10.3959/1536-1098-75.1.67Tree-Ring Researchv. 75No. 1677267–721536-1098
Helcoski, Ryan, Tepley, Alan J., McGarvey, Jennifer C., Gonzalez-Akre, Erika, Meakem, Victoria, Thompson, Jonathan R., and Anderson-Teixeira, Kristina J. 2019. "No significant increase in tree mortality following coring in a temperate hardwood forest." Tree-Ring Research 75 (1):67–72. https://doi.org/10.3959/1536-1098-75.1.67
ID: 150142
Type: article
Authors: Helcoski, Ryan; Tepley, Alan J.; McGarvey, Jennifer C.; Gonzalez-Akre, Erika; Meakem, Victoria; Thompson, Jonathan R.; Anderson-Teixeira, Kristina J.
Keywords: STRI; NZP
Abstract: The collection of tree-ring data from living trees is widespread and highly valuable in ecological and dendro-climatological research, yet there is concern that coring injures trees, potentially contributing to mortality. Unlike resinous conifers that can quickly compartmentalize wounds, less decay-resistant angiosperms may face more pronounced risk of injury from coring. To test if coring increases mortality rates in temperate hardwood trees, we leverage a unique dataset tracking the mortality of cored and uncored hardwood trees representing 19 species from 10 genera in a 26-ha plot in Virginia, USA. We compare mortality rates between 935 cored trees and 8,605 uncored trees for seven years following coring. Annual mortality rates did not differ between cored trees (1.71% yr−1; 95% CI 1.40 to 2.20)and uncored trees (1.85% yr−1; 95% CI 1.70 to 2.28)across the full dataset , nor were there differences by genus or size class. These results indicate that the risk of hardwood mortality due to increment coring is probably lower than previously assumed. However, these results cannot rule out the possibility that coring elevates hardwood mortality in other climates or when trees face multiple additional stressors that were not prevalent over the course of our study.
Growing season moisture drives interannual variation in woody productivity of a temperate deciduous forestHelcoski, RyanTepley, Alan J.Pederson, NeilMcGarvey, Jennifer C.Meakem, VictoriaHerrmann, ValentineThompson, Jonathan R.Anderson-Teixeira, Kristina J.2019DOI: info:10.1111/nph.15906New Phytologistv. 223No. 3120412161204–12160028-646X
Helcoski, Ryan, Tepley, Alan J., Pederson, Neil, McGarvey, Jennifer C., Meakem, Victoria, Herrmann, Valentine, Thompson, Jonathan R., and Anderson-Teixeira, Kristina J. 2019. "Growing season moisture drives interannual variation in woody productivity of a temperate deciduous forest." New Phytologist 223 (3):1204–1216. https://doi.org/10.1111/nph.15906
ID: 151333
Type: article
Authors: Helcoski, Ryan; Tepley, Alan J.; Pederson, Neil; McGarvey, Jennifer C.; Meakem, Victoria; Herrmann, Valentine; Thompson, Jonathan R.; Anderson-Teixeira, Kristina J.
Keywords: NZP; STRI
Abstract: 1.The climate sensitivity of forest ecosystem woody productivity (ANPPstem ) influences carbon cycle responses to climate change. For the first time, we combine long-term annual growth and forest census data of a diverse temperate broadleaf deciduous forest, seeking to resolve whether ANPPstem is primarily moisture- or energy-limited and whether climate sensitivity has changed in recent decades characterized by more mesic conditions and elevated CO2 . 2.We analyzed tree-ring chronologies across 109 years of monthly climatic variation (1901-2009) for 14 species representing 97% of ANPPstem in a 25.6-ha plot in northern Virginia, USA. 3.Radial growth of most species and ecosystem-level ANPPstem responded positively to cool, moist growing season conditions, but the same conditions in the previous May-July were associated with reduced growth. In recent decades (1980-2009), responses were more variable and on average, weaker. 4.Our results indicate that woody productivity is primarily limited by current growing season moisture, as opposed to temperature or sunlight, but additional complexity in climate sensitivity may reflect the use of stored carbohydrate reserves. Overall, while such forests currently display limited moisture sensitivity, their woody productivity is likely to decline under projected hotter and potentially drier growing season conditions. This article is protected by copyright. All rights reserved.
Alternative stable equilibria and critical thresholds created by fire regimes and plant responses in a fire-prone communityMiller, Adam D.Thompson, Jonathan R.Tepley, Alan J.Anderson-Teixeira, Kristina J.2019DOI: info:10.1111/ecog.03491Ecographyv. 42No. 1556655–660906-7590
Miller, Adam D., Thompson, Jonathan R., Tepley, Alan J., and Anderson-Teixeira, Kristina J. 2019. "Alternative stable equilibria and critical thresholds created by fire regimes and plant responses in a fire-prone community." Ecography 42 (1):55–66. https://doi.org/10.1111/ecog.03491
ID: 148536
Type: article
Authors: Miller, Adam D.; Thompson, Jonathan R.; Tepley, Alan J.; Anderson-Teixeira, Kristina J.
Keywords: STRI; NZP
Abstract: Wildfire is a dominant disturbance in many ecosystems, and fire frequency and intensity are being altered as climates change. Through effects on mortality and regeneration, fire affects plant community composition, species richness, and carbon cycling. In some regions, changes to fire regimes could result in critical, non-reversible transitions from forest to non-forested states. For example, the Klamath ecoregion (northwest United States) supports extensive conifer forests that are initially replaced by hardwood chaparral following high-severity fire, but eventually return to conifer forest during the fire-free periods. Climate change alters both the fire regime and post-fire recovery dynamics, potentially causing shrubland to persist as a stable (i.e. self-renewing) vegetation stage, rather than an ephemeral stage. Here, we present a theoretical investigation of how changes in plant traits and fire regimes can alter the stability of communities in forest-shrub systems such as the Klamath. Our model captures the key characteristics of the system, including life-stage-specific responses to disturbance and asymmetrical competitive interactions. We assess vegetation stability via invasion analysis, and conclude that portions of the landscape that are currently forested also can be stable as shrubland. We identify parameter thresholds where community equilibria change from stable to unstable, and show how these thresholds may shift in response to changes in life-history or environmental parameters. For instance, conifer maturation rates are expected to decrease as aridity increases under climate change, and our model shows that this reduction decreases the fire frequencies at which forests become unstable. Increases in fire activity sufficient to destabilize forest communities are likely to occur in more arid future climates. If widespread, this would result in reduced carbon stocks and a positive feedback to climate change. Changes in stability may be altered by management practices.
ForC: A global database of forest carbon stocks and fluxesAnderson-Teixeira, Kristina J.Wang, Maria M. H.McGarvey, Jennifer C.Herrmann, ValentineTepley, Alan J.Bond-Lamberty, BenLeBauer, David S.2018DOI: info:10.1002/ecy.2229Ecologyv. 99No. 6150715070012-9658
Anderson-Teixeira, Kristina J., Wang, Maria M. H., McGarvey, Jennifer C., Herrmann, Valentine, Tepley, Alan J., Bond-Lamberty, Ben, and LeBauer, David S. 2018. "ForC: A global database of forest carbon stocks and fluxes." Ecology 99 (6):1507. https://doi.org/10.1002/ecy.2229
ID: 146200
Type: article
Authors: Anderson-Teixeira, Kristina J.; Wang, Maria M. H.; McGarvey, Jennifer C.; Herrmann, Valentine; Tepley, Alan J.; Bond-Lamberty, Ben; LeBauer, David S.
Keywords: STRI; NZP
Abstract: Forests play an influential role in the global carbon (C) cycle, storing roughly half of terrestrial C and annually exchanging with the atmosphere more than ten times the carbon dioxide (CO2) emitted by anthropogenic activities. Yet, scaling up from field-based measurements of forest C stocks and fluxes to understand global scale C cycling and its climate sensitivity remains an important challenge. Tens of thousands of forest C measurements have been made, but these data have yet to be integrated into a single database that makes them accessible for integrated analyses. Here we present an open-access global Forest Carbon database (ForC) containing previously published records of field-based measurements of ecosystem-level C stocks and annual fluxes, along with disturbance history and methodological information. ForC expands upon the previously published tropical portion of this database, TropForC (DOI: 10.5061/dryad.t516f), now including 17,367 records (previously 3,568) representing 2,731 plots (previously 845) in 826 geographically distinct areas. The database covers all forested biogeographic and climate zones, represents forest stands of all ages, and currently includes data collected between 1934 and 2015. We expect that ForC will prove useful for macroecological analyses of forest C cycling, for evaluation of model predictions or remote sensing products, for quantifying the contribution of forests to the global C cycle, and for supporting international efforts to inventory forest carbon and greenhouse gas exchange. A dynamic version of ForC is maintained at on GitHub (https://GitHub.com/forc-db), and we encourage the research community to collaborate in updating, correcting, expanding, and utilizing this database. ForC is an open access database, and we encourage use of the data for scientific research and education purposes. Data may not be used for commercial purposes without written permission of the database PI. Any publications using ForC data should cite this publication and Anderson-Teixeira et al. 2016(a) (see Metadata S1). No other copyright or cost restrictions are associated with the use of this dataset. This article is protected by copyright. All rights reserved.
Role of tree size in moist tropical forest carbon cycling and water deficit responsesMeakem, VictoriaTepley, Alan J.Gonzalez-Akre, ErikaHerrmann, ValentineMuller-Landau, Helene C.Wright, S. JosephHubbell, Stephen P.Condit, Richard S.Anderson-Teixeira, Kristina J.2018DOI: info:10.1111/nph.14633New Phytologistv. 219No. 3947958947–9580028-646X
Meakem, Victoria, Tepley, Alan J., Gonzalez-Akre, Erika, Herrmann, Valentine, Muller-Landau, Helene C., Wright, S. Joseph, Hubbell, Stephen P., Condit, Richard S., and Anderson-Teixeira, Kristina J. 2018. "Role of tree size in moist tropical forest carbon cycling and water deficit responses." New Phytologist 219 (3):947–958. https://doi.org/10.1111/nph.14633
Disequilibrium of fire-prone forests sets the stage for a rapid decline in conifer dominance during the 21st centurySerra-Diaz, JosepMaxwell, CharlesLucash, Melissa S.Scheller, Robert M.Laflower, Danelle M.Miller, Adam D.Tepley, Alan J.Epstein, Howard E.Anderson-Teixeira, Kristina J.Thompson, Jonathan R.2018DOI: info:10.1038/s41598-018-24642-2Scientific Reportsv. 8No. 1Article 6749Article 67492045-2322
Serra-Diaz, Josep, Maxwell, Charles, Lucash, Melissa S., Scheller, Robert M., Laflower, Danelle M., Miller, Adam D., Tepley, Alan J., Epstein, Howard E., Anderson-Teixeira, Kristina J., and Thompson, Jonathan R. 2018. "Disequilibrium of fire-prone forests sets the stage for a rapid decline in conifer dominance during the 21st century." Scientific Reports 8 (1):Article 6749. https://doi.org/10.1038/s41598-018-24642-2
ID: 146306
Type: article
Authors: Serra-Diaz, Josep; Maxwell, Charles; Lucash, Melissa S.; Scheller, Robert M.; Laflower, Danelle M.; Miller, Adam D.; Tepley, Alan J.; Epstein, Howard E.; Anderson-Teixeira, Kristina J.; Thompson, Jonathan R.
Keywords: NZP; STRI
Abstract: The impacts of climatic changes on forests may appear gradually on time scales of years to centuries due to the long generation times of trees. Consequently, current forest extent may not reflect current climatic patterns. In contrast with these lagged responses, abrupt transitions in forests under climate change may occur in environments where alternative vegetation states are influenced by disturbances, such as fire. The Klamath forest landscape (northern California and southwest Oregon, USA) is currently dominated by high biomass, biodiverse temperate coniferous forests, but climate change could disrupt the mechanisms promoting forest stability (e.g. growth, regeneration and fire tolerance). Using a landscape simulation model, we estimate that about one-third of the Klamath forest landscape (500,000 ha) could transition from conifer-dominated forest to shrub/hardwood chaparral, triggered by increased fire activity coupled with lower post-fire conifer establishment. Such shifts were widespread under the warmer climate change scenarios (RCP 8.5) but were surprisingly prevalent under the climate of 1949-2010, reflecting the joint influences of recent warming trends and the legacy of fire suppression that may have enhanced conifer dominance. Our results demonstrate that major forest ecosystem shifts should be expected when climate change disrupts key stabilizing feedbacks that maintain the dominance of long-lived, slowly regenerating trees.
Influences of fire-vegetation feedbacks and post-fire recovery rates on forest landscape vulnerability to altered fire regimesTepley, Alan J.Thomann, EnriqueVeblen, Thomas T.Perry, George L. W.Holz, AndresParitsis, JuanKitzberger, ThomasAnderson-Teixeira, Kristina J.2018DOI: info:10.1111/1365-2745.12950Journal of Ecologyv. 106No. 5192519401925–19400022-0477
Tepley, Alan J., Thomann, Enrique, Veblen, Thomas T., Perry, George L. W., Holz, Andres, Paritsis, Juan, Kitzberger, Thomas, and Anderson-Teixeira, Kristina J. 2018. "Influences of fire-vegetation feedbacks and post-fire recovery rates on forest landscape vulnerability to altered fire regimes." Journal of Ecology 106 (5):1925–1940. https://doi.org/10.1111/1365-2745.12950
ID: 149691
Type: article
Authors: Tepley, Alan J.; Thomann, Enrique; Veblen, Thomas T.; Perry, George L. W.; Holz, Andres; Paritsis, Juan; Kitzberger, Thomas; Anderson-Teixeira, Kristina J.
Keywords: NZP; STRI
Abstract: 1. In the context of ongoing climatic warming, forest landscapes face increasing risk of conversion to non-forest vegetation through alteration of their fire regimes and their post-fire recovery dynamics. However, this pressure could be amplified or dampened, depending on how fire-driven changes to vegetation feed back to alter the extent or behaviour of subsequent fires. 2. Here we develop a mathematical model to formalize understanding of how fire-vegetation feedbacks and the time to forest recovery following high-severity (i.e. stand-replacing) fire affect the extent and stability of forest cover across landscapes facing altered fire regimes. We evaluate responses to increasing burn rates while varying the direction (negative vs. positive) of fire-vegetation feedbacks under a continuum of values for feedback strength and post-fire recovery time. In doing so, we determine how interactions among these variables produce thresholds and tipping points in landscape responses to changing fire regimes. 3. Where the early-seral vegetation was less fire-prone than older forests, negative feedbacks limited the reductions in forest cover in response to higher fire frequency or slower forest recovery. By contrast, positive feedbacks (more flammable early-seral vegetation) produced a tipping point beyond which increases in burn rates or a slowing of forest recovery drove extensive forest loss. 4. With negative feedbacks, the rates of forest loss and expansion in response to variation in fire frequency were similar. However, where feedbacks were positive, the conversion from predominantly forested to non-forested conditions in response to increasing fire frequency was faster than the re-expansion of forest cover following a return to the initial burn rate. Strengthening the positive feedbacks increased this asymmetry. 5. Synthesis. Our analyses elucidate how fire-vegetation feedbacks and post-fire recovery rates interact to affect the trajectories and rates of landscape response to altered fire regimes. We illustrate the vulnerability of ecosystems with positive fire-vegetation feedbacks to climate change-driven increases in fire activity, especially where post-fire recovery is slow. Although negative feedbacks initially provide resistance to forest loss with increasing burn rates, this resistance is eventually overwhelmed with sufficient increases to burn rates relative to recovery times.
Patterns of tree mortality in a temperate deciduous forest derived from a large forest dynamics plotGonzalez-Akre, ErikaMeakem, VictoriaEng, Cheng-YinTepley, Alan J.Bourg, Norman A.McShea, William J.Davies, Stuart J.Anderson-Teixeira, Kristina J.2017DOI: info:10.5479/data_scbi/10088/31954Smithsonian Tropical Research Institute
Gonzalez-Akre, Erika, Meakem, Victoria, Eng, Cheng-Yin, Tepley, Alan J., Bourg, Norman A., McShea, William J., Davies, Stuart J., and Anderson-Teixeira, Kristina J. 2017. [Dataset] "Patterns of tree mortality in a temperate deciduous forest derived from a large forest dynamics plot." Distributed by Smithsonian Tropical Research Institute. https://doi.org/10.5479/data_scbi/10088/31954
ID: 143607
Type: dataset
Authors: Gonzalez-Akre, Erika; Meakem, Victoria; Eng, Cheng-Yin; Tepley, Alan J.; Bourg, Norman A.; McShea, William J.; Davies, Stuart J.; Anderson-Teixeira, Kristina J.
Keywords: STRI; Dataset; NZP
Vulnerability to forest loss through altered postfire recovery dynamics in a warming climate in the Klamath MountainsTepley, Alan J.Thompson, Jonathan R.Epstein, Howard E.Anderson-Teixeira, Kristina J.2017DOI: info:10.1111/gcb.13704Global Change Biologyv. 23No. 10411741324117–41321354-1013
Tepley, Alan J., Thompson, Jonathan R., Epstein, Howard E., and Anderson-Teixeira, Kristina J. 2017. "Vulnerability to forest loss through altered postfire recovery dynamics in a warming climate in the Klamath Mountains." Global Change Biology 23 (10):4117–4132. https://doi.org/10.1111/gcb.13704
ID: 142715
Type: article
Authors: Tepley, Alan J.; Thompson, Jonathan R.; Epstein, Howard E.; Anderson-Teixeira, Kristina J.
Keywords: STRI; NZP
Patterns of tree mortality in a temperate deciduous forest derived from a large forest dynamics plotGonzalez-Akre, ErikaMeakem, VictoriaEng, Cheng-YinTepley, Alan J.Bourg, Norman A.McShea, William J.Davies, Stuart J.Anderson-Teixeira, Kristina J.2016DOI: info:10.1002/ecs2.1595Ecospherev. 7No. 122150-8925
Gonzalez-Akre, Erika, Meakem, Victoria, Eng, Cheng-Yin, Tepley, Alan J., Bourg, Norman A., McShea, William J., Davies, Stuart J., and Anderson-Teixeira, Kristina J. 2016. "Patterns of tree mortality in a temperate deciduous forest derived from a large forest dynamics plot." Ecosphere 7 (12):https://doi.org/10.1002/ecs2.1595
ID: 141218
Type: article
Authors: Gonzalez-Akre, Erika; Meakem, Victoria; Eng, Cheng-Yin; Tepley, Alan J.; Bourg, Norman A.; McShea, William J.; Davies, Stuart J.; Anderson-Teixeira, Kristina J.
Keywords: NZP; STRI; NMNH
Patterns of tree mortality in a temperate deciduous forest derived from a large forest dynamics plot - 2014 and 2015Gonzalez-Akre, ErikaMeakem, VictoriaEng, Cheng-YinTepley, Alan J.Bourg, Norman A.McShea, WilliamDavies, Stuart J.Anderson-Teixeira, Kristina J.2016Dryad Digital Repository
Gonzalez-Akre, Erika, Meakem, Victoria, Eng, Cheng-Yin, Tepley, Alan J., Bourg, Norman A., McShea, William, Davies, Stuart J., and Anderson-Teixeira, Kristina J. 2016. [Dataset] "Patterns of tree mortality in a temperate deciduous forest derived from a large forest dynamics plot - 2014 and 2015." Distributed by Dryad Digital Repository.
ID: 153079
Type: dataset
Authors: Gonzalez-Akre, Erika; Meakem, Victoria; Eng, Cheng-Yin; Tepley, Alan J.; Bourg, Norman A.; McShea, William; Davies, Stuart J.; Anderson-Teixeira, Kristina J.
Keywords: Dataset; NZP; STRI
Positive Feedbacks to Fire-Driven Deforestation Following Human Colonization of the South Island of New ZealandTepley, Alan J.Veblen, Thomas T.Perry, George L. W.Stewart, Glenn H.Naficy, Cameron E.2016DOI: info:10.1007/s10021-016-0008-9Ecosystemsv. 19No. 8132513441325–13441432-9840
Tepley, Alan J., Veblen, Thomas T., Perry, George L. W., Stewart, Glenn H., and Naficy, Cameron E. 2016. "Positive Feedbacks to Fire-Driven Deforestation Following Human Colonization of the South Island of New Zealand." Ecosystems 19 (8):1325–1344. https://doi.org/10.1007/s10021-016-0008-9
ID: 139773
Type: article
Authors: Tepley, Alan J.; Veblen, Thomas T.; Perry, George L. W.; Stewart, Glenn H.; Naficy, Cameron E.
Keywords: NZP
Abstract: Altered fire regimes in the face of climatic and land-use change could potentially transform large areas from forest to shorter-statured or open-canopy vegetation. There is growing concern that once initiated, these nonforested landscapes could be perpetuated almost indefinitely through a suite of positive feedbacks with fire. The rapid deforestation of much of New Zealand following human settlement (ca. 750 years ago) provides a rare opportunity to evaluate the feedback mechanisms that facilitated such extensive transformation and thereby help us to identify factors that confer vulnerability or resilience to similar changes in other regions. Here we evaluate the structure of living and dead vegetation (fuel loading) and microclimate (fuel moisture) in beech (Nothofagaceae) forests and adjacent stands that burned within the last 60–140 years and are dominated by mānuka (Leptospermum scoparium) or kānuka (Kunzea spp.). We show that the burning of beech forests initiates a positive feedback cycle whereby the loss of microclimatic amelioration under the dense forest canopy and the abundant fine fuels that dry readily beneath the sparse mānuka/kānuka canopy enables perpetuation of these stands by facilitating repeated burning. Beech regeneration was limited to a narrow zone along the margin of unburned stands. The high flammability of vegetation that develops after fire and the long time to forest recovery were the primary factors that facilitated extensive deforestation with the introduction of human-ignited fire. Evaluating these two characteristics may be key to determining which regions may be near a tipping point where relatively small land-use- or climatically driven changes to fire regimes could bring about extensive deforestation.
Interactions among spruce beetle disturbance, climate change and forest dynamics captured by a forest landscape modelTemperli, ChristianVeblen, Thomas T.Hart, Sarah J.Kulakowski, DominikTepley, Alan J.2015DOI: info:10.1890/ES15-00394.1Ecospherev. 6No. 112150-8925
Temperli, Christian, Veblen, Thomas T., Hart, Sarah J., Kulakowski, Dominik, and Tepley, Alan J. 2015. "Interactions among spruce beetle disturbance, climate change and forest dynamics captured by a forest landscape model." Ecosphere 6 (11):https://doi.org/10.1890/ES15-00394.1
ID: 138232
Type: article
Authors: Temperli, Christian; Veblen, Thomas T.; Hart, Sarah J.; Kulakowski, Dominik; Tepley, Alan J.
Keywords: NZP
Abstract: The risk of bark beetle outbreaks is widely predicted to increase because of a warming climate that accelerates temperature-driven beetle population growth and drought stress that impairs host tree defenses. However, few if any studies have explicitly evaluated climatically enhanced beetle population dynamics in relation to climate-driven changes in forest composition and structure that may alter forest suitability for beetle infestation. We synthesized current understanding of the interactions among climate, spruce beetles (Dendroctonus rufipennis) and forest dynamics to parameterize and further advance the bark beetle module of a dynamic forest landscape model (LandClim) that also integrates fire and wind disturbance and climate-driven forest succession. We applied the model to a subalpine watershed in northwestern Colorado to examine the mechanisms and feedbacks that may lead to shifts in forest composition and spruce beetle disturbance under three climate change scenarios. Simulation results suggest increased drought- and beetle-induced reduction of large Engelmann spruce (Picea engelmannii) trees while Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) increased in dominance throughout the study area under all climate change scenarios. This shift in forest composition and structure counterbalances the enhancing effects of accelerated beetle population development and increased drought-induced susceptibility of spruce to beetles. As a result, we projected a long-term decrease in beetle-induced spruce mortality to below historical values under all climate scenarios at low elevations (<2800 m asl). Beetle-induced spruce mortality above 2800 m asl and under moderate climate change was slightly higher and more variable than under historical conditions but decreased to 36% and 6% of historical values under intermediate and extreme climate change, respectively. Because mechanisms driving beetle disturbance dynamics are similar across different bark beetle species, we argue that the depletion of host trees due to drought and beetle disturbance may also be important in other climate-sensitive beetle-host systems. We advocate for the consideration of climate-driven shifts in forest and disturbance dynamics in devising adaptive management strategies.