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Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
Linking Old-Growth Forest Composition, Structure, Fire History, Climate And Land-Use In The Mountains Of Northern México, Citlali Cortes Montano, Peter Z. Fule, Donald A. Falk, Jose Villanueva-Diaz, Larissa L. Yocom Kent
Linking Old-Growth Forest Composition, Structure, Fire History, Climate And Land-Use In The Mountains Of Northern México, Citlali Cortes Montano, Peter Z. Fule, Donald A. Falk, Jose Villanueva-Diaz, Larissa L. Yocom Kent
Wildland Resources Faculty Publications
Old-growth forests are biologically and ecologically valuable systems that are disappearing worldwide at a rapid rate. México still holds large areas covered by temperate forests in the mountains of the Sierra Madre Occidental, but few of these retain old-growth characteristics. We studied four sites with remnant old-growth forests in Mesa de las Guacamayas, a site in the Sierra Madre Occidental in northwestern Chihuahua, to assess their composition, structure, and age characteristics. Overstory tree densities and basal areas at each site were based on measurements of all trees >1.3 m tall. The overstory was dominated by large Pinus durangensis, P. strobiformis, …
Testing A Pyroclimatic Hypothesis On The Mexico-United States Border, Peter Z. Fule, Larissa L. Yocom Kent, Citlali Cortes Montano, Donald A. Falk, Julian Cerano, Jose Villanueva-Diaz
Testing A Pyroclimatic Hypothesis On The Mexico-United States Border, Peter Z. Fule, Larissa L. Yocom Kent, Citlali Cortes Montano, Donald A. Falk, Julian Cerano, Jose Villanueva-Diaz
Wildland Resources Faculty Publications
The “pyroclimatic hypothesis” proposed by F. Biondi and colleagues provides a basis for testable expectations about climatic and other controls of fire regimes. This hypothesis asserts an a priori relationship between the occurrence of widespread fire and values of a relevant climatic index. Such a hypothesis provides the basis for predicting spatial and temporal patterns of fire occurrence based on climatic control. Forests near the Mexico–United States border offer a place to test the relative influence of climatic and other controls in mountain ranges that are ecologically similar and subject to broadly similar top-down climatic influence, but with differing cultural …
Leaf Area And Structural Changes After Thinning In Even-Aged Picea Rubens And Abies Balsamea Stands In Maine, Usa, R. Justin Derose, Robert S. Seymour
Leaf Area And Structural Changes After Thinning In Even-Aged Picea Rubens And Abies Balsamea Stands In Maine, Usa, R. Justin Derose, Robert S. Seymour
Wildland Resources Faculty Publications
We tested the hypothesis that changes in leaf area index (LAI m2 m−2) and mean stand diameter following thinning are due to thinning type and residual density. The ratios of pre- to postthinning diameter and LAI were used to assess structural changes between replicated crown, dominant, and low thinning treatments to 33% and 50% residual density in even-aged Picea rubens and Abies balsamea stands with and without a precommercial thinning history in Maine, USA. Diameter ratios varied predictably by thinning type: low thinnings were 0.7 but 1.0 . LAI change was affected by type and intensity of thinning. On average, …
The Glass Is Half-Full: Overestimating The Quality Of A Novel Environment Is Advantageous, Oded Berger-Tal, Tal Avgar
The Glass Is Half-Full: Overestimating The Quality Of A Novel Environment Is Advantageous, Oded Berger-Tal, Tal Avgar
Wildland Resources Faculty Publications
According to optimal foraging theory, foraging decisions are based on the forager's current estimate of the quality of its environment. However, in a novel environment, a forager does not possess information regarding the quality of the environment, and may make a decision based on a biased estimate. We show, using a simple simulation model, that when facing uncertainty in heterogeneous environments it is better to overestimate the quality of the environment (to be an “optimist”) than underestimate it, as optimistic animals learn the true value of the environment faster due to higher exploration rate. Moreover, we show that when the …
Establishment Of Introduced Reptiles Increases With The Presence And Richness Of Native Congeners, Rodrigo Barbosa Ferreira, Karen H. Beard, Stephen L. Peterson, Sharon A. Poessel, Colin M. Callahan
Establishment Of Introduced Reptiles Increases With The Presence And Richness Of Native Congeners, Rodrigo Barbosa Ferreira, Karen H. Beard, Stephen L. Peterson, Sharon A. Poessel, Colin M. Callahan
Wildland Resources Faculty Publications
Darwin proposed two contradictory hypotheses to explain the influence of congeners on the outcomes of invasion: the naturalization hypothesis, which predicts a negative relationship between the presence of congeners and invasion success, and the pre-adaptation hypothesis, which predicts a positive relationship between the presence of congeners and invasion success. Studies testing these hypotheses have shown mixed support. We tested these hypotheses using the establishment success of non-native reptiles and congener presence/absence and richness across the globe. Our results demonstrated support for the pre-adaptation hypothesis. We found that globally, both on islands and continents, establishment success was higher in the presence …
Plant-Soil Feedbacks Provide An Alternative Explanation For Diversity-Productivity Relationships, Andrew Kulmatiski, Karen H. Beard, Justin Heavilin
Plant-Soil Feedbacks Provide An Alternative Explanation For Diversity-Productivity Relationships, Andrew Kulmatiski, Karen H. Beard, Justin Heavilin
Wildland Resources Faculty Publications
Plant–soil feedbacks (PSFs) have gained attention for their role in plant community dynamics, but their role in productivity has been overlooked. We developed and tested a biomass-specific, multi-species model to examine the role of PSFs in diversity–productivity relationships. The model predicts a negative relationship between PSFs and overyielding: plants with negative PSFs grow more in communities than in monoculture (i.e. overyield), and plants with positive PSFs grow less in communities than in monoculture (i.e. underyield). This effect is predicted to increase with diversity and saturate at low species richness because the proportion of ‘self-cultivated’ soils rapidly decreases as species are …