Biotic Impoverishment and Climate Change: Global Causes of Forest Decline?

Author(s):  
D. Mueller-Dombois
2011 ◽  
Vol 11 (3) ◽  
pp. 85-103 ◽  
Author(s):  
Constance L. McDermott ◽  
Kelly Levin ◽  
Benjamin Cashore

For those championing an international institutional solution to climate change, the forest-climate linkage through reduced emissions from deforestation and forest degradation and forest enhancement (REDD+) may be one of the most promising strategic linkages to date. Following a series of forest-focused interventions that did not live up to their promise, global forest politics have now, through REDD+ deliberations, been institutionally subsumed into the climate regime. We argue that to realize its potential, REDD+ policy mechanisms must be careful to move away from the commodification of forest stewardship that reinforces short-term strategic positions of powerful producing and consuming interests whose current activities are the culprits of global forest decline. To achieve such an outcome, we argue that institutions must develop on the basis of a “logic of problem amelioration” in which the rationale for achieving clearly defined environmental and social goals is rendered transparent. This could be achieved through the formalization of a “dual effectiveness test” in which interventions are evaluated for their potential to simultaneously ameliorate both global climate change and forest degradation.


2013 ◽  
Vol 164 (11) ◽  
pp. 315-320
Author(s):  
Michèle Kaennel Dobbertin

Forest decline in New Mexico: what shall we tell the kids? (Essay) Climate change-related drought and higher temperatures may directly or indirectly cause forests to die or to be replaced by another vegetation type. As suggested, among others, by two international scientific articles published in 2010 and 2012, the magnitude of these phenomena may be greater than expected. No matter how relevant these studies are, their potential negative impact on the general public should not be underestimated, in particular if the media overstate or distort the scientists' conclusions. Looking back at the forest decline debate of the 1990s and based on discussions with an American forest ecologist, this article offers positive approaches to communicate to the general public an environmental issue to be taken seriously.


2020 ◽  
Vol 50 (9) ◽  
pp. 843-854 ◽  
Author(s):  
Cuauhtémoc Sáenz-Romero ◽  
Eduardo Mendoza-Maya ◽  
Erika Gómez-Pineda ◽  
Arnulfo Blanco-García ◽  
Angel R. Endara-Agramont ◽  
...  

Symptoms of forest decline, apparently due to climate change, have become evident in the last 10 years on the Trans-Mexican Volcanic Belt and northwestern temperate forest of Mexico, particularly at the xeric (low elevational) limit of several forest tree species. We review and provide recent evidence of massive infestation of timberline Pinus hartwegii Lindl. by the mistletoes Arceuthobium globosum Hawksw. & Wiens and Arceuthobium vaginatum (Humb. & Bonpl. ex Willd.) J.Presl; insufficient Abies religiosa (Kunth) Schltdl. & Cham. seedling recruitment at the Monarch Butterfly Biosphere Reserve; indications of inbreeding and defoliation in endangered Picea chihuahuana Martínez, Picea martinezii T.F. Patt., Picea mexicana Martínez, and extreme southern populations of Pseudotsuga menziesii (Mirb.) Franco; and the incidence of unusual pest and disease outbreaks (e.g., Dendroctonus Erichson, 1836 spp., Neodiprion autumnalis Smith, and Phytophthora cinnamomi Rands) in several conifer and oak species. We also discuss a difficult question: Is natural genetic variation sufficient to provide populations with the adaptive variation necessary to survive the natural selection imposed by projected climate change scenarios, or will phenotypic plasticity be exhausted and populations decline? Controversial ex situ conservation within natural protected areas, assisted migration, and translocation of species ensembles are discussed as options by which to accommodate projected climatic change impacts on the management and conservation practices of the megadiverse Mexican temperate forest.


2012 ◽  
Vol 20 (2) ◽  
pp. 109-121 ◽  
Author(s):  
Weifeng Wang ◽  
Changhui Peng ◽  
Daniel D. Kneeshaw ◽  
Guy R. Larocque ◽  
Zhibin Luo

Drought-induced tree mortality, which rapidly alters forest ecosystem composition, structure, and function, as well as the feedbacks between the biosphere and climate, has occurred worldwide over the past few decades, and is expected to increase pervasively as climate change progresses. The objectives of this review are to (1) highlight the likely ecological consequences of drought-induced tree mortality, (2) synthesize the hypotheses related to drought-induced tree mortality, (3) discuss the implications of current knowledge for modeling tree mortality processes under climate change, and (4) highlight future research needs. First, we emphasize the likely ecological consequences of tree mortality from ecosystem to biome to continental scales. We then document and criticize multiple non-exclusive tree mortality hypotheses (e.g., carbon starvation — carbon supply is less than carbon demand; and hydraulic failure — desiccation from failed water transport) from a more comprehensive ecological perspective. Next, we extend a forest decline concept model, Manion’s framework, by considering new emerging environmental conditions, for a more thorough understanding of the effects of climate change on forest decline. We find that an increase in drought frequency and (or) climate-change-type droughts may trigger increased background tree mortality rates and severe forest dieback events, accelerating species turnover and ecological regime shifts. The contribution of CO2 fertilization, rising temperature within the optimal growth range, and increased nitrogen deposition may defer or reduce this trend in tree mortality, but such contributions will vary between locations, species, and tree sizes. Multiple hypotheses proposed for drought-induced tree mortality are discussed, but coupling carbon and water cycles could help resolve the debate. The absence of a physiological understanding of tree mortality mechanisms limits the predictive ability of current models from stand-level process-based models to dynamic global vegetation models. We thus suggest that long-term observations, experiments, and models should be tightly interwoven during the research process to better forecast future climate changes and evaluate their impacts on forests.


Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 487
Author(s):  
Juan Miguel Moya-Pérez ◽  
María Francisca Carreño ◽  
Miguel Ángel Esteve-Selma

The southeast Iberian Peninsula is the only place in the European Community where Tetraclinis articulata (Vahl) Masters populations are native. In this area, the optimal ecological niche for this species is occupied by Pinus halepensis (Miller). The increasing intensity of extreme drought events induced by climate change causes severe declines in pine forests, while providing expansion opportunities for established Tetraclinis populations. Within the framework of the LIFE-TETRACLINIS project, a study has been designed to simulate the pine forest decline effects on the population dynamics of this protected species. This work investigates the effects of decreasing competition on T. articulata specimens with limited reproductive activity. To induce the reproductive activity of these specimens through increasing the availability of light, the surrounding pines were removed within a 15 m radius. Increased light availability was modelled using “Light Detection And Ranging” (LiDAR) data, and changes in the main reproductive parameters were registered throughout the study period. A significant increase in the reproductive population was achieved, as well as the cones produced per specimen and the recruitment. Findings obtained are promising for the habitat management in continental Europe and enhancing this forest system’s resilience to extreme drought events and climate change.


2021 ◽  
Vol 12 ◽  
Author(s):  
Allan Buras ◽  
Anja Rammig ◽  
Christian S. Zang

Forest decline, in course of climate change, has become a frequently observed phenomenon. Much of the observed decline has been associated with an increasing frequency of climate change induced hotter droughts while decline induced by flooding, late-frost, and storms also play an important role. As a consequence, tree mortality rates have increased across the globe. Despite numerous studies that have assessed forest decline and predisposing factors for tree mortality, we still lack an in-depth understanding of (I) underlying eco-physiological mechanisms, (II) the influence of varying environmental conditions related to soil, competition, and micro-climate, and (III) species-specific strategies to cope with prolonged environmental stress. To deepen our knowledge within this context, studying tree performance within larger networks seems a promising research avenue. Ideally such networks are already established during the actual period of environmental stress. One approach for identifying stressed forests suitable for such monitoring networks is to assess measures related to tree vitality in near real-time across large regions by means of satellite-borne remote sensing. Within this context, we introduce the European Forest Condition monitor (EFCM)—a remote-sensing based, freely available, interactive web information tool. The EFCM depicts forest greenness (as approximated using NDVI from MODIS at a spatial resolution of roughly 5.3 hectares) for the pixel-specific growing season across Europe and consequently allows for guiding research within the context of concurrent forest performance. To allow for inter-temporal comparability and account for pixel-specific features, all observations are set in relation to normalized difference vegetation index (NDVI) records over the monitoring period beginning in 2001. The EFCM provides both a quantile-based and a proportion-based product, thereby allowing for both relative and absolute comparison of forest greenness over the observational record. Based on six specific examples related to spring phenology, drought, late-frost, tree die-back on water-logged soils, an ice storm, and windthrow we exemplify how the EFCM may help identifying hotspots of extraordinary forest greenness. We discuss advantages and limitations when monitoring forest condition at large scales on the basis of moderate resolution remote sensing products to guide users toward an appropriate interpretation.


2021 ◽  
Vol 4 ◽  
Author(s):  
Aurélien Sallé ◽  
Jérémy Cours ◽  
Elodie Le Souchu ◽  
Carlos Lopez-Vaamonde ◽  
Sylvain Pincebourde ◽  
...  

Global change challenges the adaptive potential of forests. Large-scale alterations of forest canopies have been reported across Europe, and further modifications are expected in response to the predicted changes in drought and windstorm regimes. Since forest canopies are dynamic interfaces between atmosphere and land surface, communities of canopy-dwelling insects are at the forefront of major changes in response to both direct and indirect effects of climate change. First, we briefly introduce the factors shaping arthropod communities in the canopy of temperate forests. Second, we cover the significant impacts of a forest decline on canopy structure and functioning, and more specifically its contrasted effects on insect microhabitats, trophic resources and forest microclimates. Deleterious effects may be expected for several guilds of leaf-dwelling insects. Nonetheless, a forest decline could also lead to transient or long-lasting resource pulses for other canopy-dwelling guilds, especially saproxylic species depending on deadwood substrates and tree-related microhabitats. The novel microclimates may also become more favorable for some particular groups of insects. We pinpoint current knowledge gaps and the technological locks that should be undone to improve our understanding of the canopy biotope and biodiversity in temperate forests. We highlight the need for integrative approaches to reveal the mechanisms at play. We call for cross-scale studies and long-term collaborative research efforts, involving different disciplines such as community and disturbance ecology, plant and insect ecophysiology, and thermal ecology, to better anticipate ongoing functional and conservation issues in temperate forest ecosystems.


2012 ◽  
Vol 8 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Zsolt Kotroczó ◽  
Zsuzsa Veres ◽  
István Fekete ◽  
Mária Papp ◽  
János Attila Tóth

Abstract - Climate change is a global problem. During the last century the increase of annual average temperature was 0.68°C, while the decrease of annual average of precipitation was 83 mm in Hungary. According to the long term meteorological data of Síkfőkút forest ILTER site the annual average temperature increased while average of yearly precipitation decreased, the forest climate became warmer and dryer. These processes could considerably contribute to forest decline, not only in the Quercetum petraeae-cerris stand of Síkfőkút, but everywhere in the country. Species composition and structure of the forest have changed considerably, as 68% of sessile oak (Quercus petraea) and 16% of Turkey oak (Quercus cerris) have died. Forest decline resulted in the breaking up of the formerly closed canopy, and consequently, in the formation of gaps in the forest. In the gaps, a secondary canopy developed with tree species of less forestry value. As a consequence, mass regeneration of field maple (Acer campestre) appeard in the gaps. The formation of gaps accelerated the warming and aridity of forests. In the article we answer the following question: how did climatic change and changing forest structure influence the leaf-litter production in the last four decades?


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