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This paper reviews and discusses the main features of biological invasion by plants and the assisted migration theory referencing a critical common factor--belowground ecology. The risk of a plant becoming invasive and the potential failure of assisted migration programs depend on the presence or absence of soil microorganisms that regulate key ecosystem processes and mitigate adverse environmental conditions. This biotic interaction should be considered in the selection of sites for afforestation programs since it is as important as temperature and precipitation regarding conservation decisions, and assisted migration practices in response to climate change. Fungal species should be determined and included in climate change mitigation programs to avoid disease outbreaks and ensure the presence of beneficial mutualistic species in sites selected for assisted migration. Plants considered for assisted migration should pose a low risk of becoming invasive for having establishment difficulties per se. However, the real threat is that they may displace other species, introduce pathogens, or trigger disease outbreaks in introduction sites that nullify assisted migration efforts. Key words: climate change, environmental decision-making,, 1. Introduction While we know the impacts of climate change on temperate forest individuals, populations, and communities, we lack a baseline for understanding the role of microorganisms in successful assisted [...]

The conceptual framework of socio-ecological systems (SES) has been used to redirect resource management practices towards more sustainable scenarios. Utilizing surveys conducted with 350 producers of a silvopastoral cattle network in southern Mexico, the structure and interactions of cattle SES were characterized. Furthermore, based on information derived from a workshop with producers, the framework was operationalized through variables representing action situations and generating outcomes in terms of management, organizational issues, and ecosystem services. This participatory exercise allowed for the identification of locally relevant sustainability components and ranges that can be generalized to other similar SES in Latin America, specific socio-ecological challenges, and potential actions leading to maximizing the sustainability of silvopastoral ranches in the tropics. Challenges include an excessive number of intermediaries, labor conditions accentuating poverty, marketing chains inaccessible to small scale producers, and low diversification. These issues can be addressed within the cattle SES through technical and financial support from involved governmental institutions and strengthening the local governance system. This work bridges gaps in cattle research by highlighting that sustainable intensification through the establishment of silvopastoral systems is possible within specific ranges, and sustainability can be defined, understood, and built by producers from the territories. [ABSTRACT FROM AUTHOR]

Climate change has profound impacts on ecosystems, and one critical aspect is its effect on seed germination, a crucial stage in plant life cycles. Various studies have explored the responses of plant species to rising temperatures, and there is now a pressing need to integrate this wealth of information into a coherent framework. The aim of this study was to survey literature about seed traits and thence to evaluate germination responses to climate change and to propose functional groups for germination. Increased temperature affects seed traits, particularly germinability. Many species show increased germination percentages in warmer temperatures, although the extent varies among species and temperature ranges. Some maintain a consistent percentage, whereas others reduce it to retain seeds in the seed bank. Temperature changes also affect the timing and season of germination, with some species accelerating germination, others delaying it, thereby influencing competition and exposure to adverse conditions. Shifts in temperature can alter seed requirements, affecting responses to temperature, humidity, light, chemical stimuli, and dormancy. Modifications in germination have profound effects on seed bank and seedling bank dynamics, affecting plant populations and ecological community resilience. Changes in germination can disrupt competitive dynamics, favoring some over others, altering community composition, and potentially impairing ecosystem functionality. Germination niche, germination potential, and germination phenology are fundamental concepts in the evaluation of climate change's implications for germination. [ABSTRACT FROM AUTHOR]

Vegetation-soil systems differentially influence the ecosystem processes related to the carbon cycle, particularly when one tree species is dominant over wide geographic regions that are undergoing climate change. The objective of this study was to quantify the stocks of ecosystem carbon in three vegetation-soil systems along a highland elevational gradient in central Mexico. The vegetation-soil systems, from lower to higher elevation, were dominated by Alnus jorullensis Kunth, Abies religiosa (Kunth) Schltdl. & Cham., and Pinus hartwegii Lindl., respectively. Above- and below-ground tree biomass was determined in each system, along with the litter, coarse woody material, roots, and litterfall. The A. religiosa system had the greatest stock of aboveground biomass carbon (216 [+ or -] 31 Mg C x [ha.sup.-1]). The A. jorullensis system had the greatest production of litterfall (3.1 [+ or -] 0.08 Mg x [ha.sup.-1] x [year.sup.-1]); however, the carbon content of this litter layer (1.2 [+ or -] 0.32 Mg C x [ha.sup.-1]) was lower than that of P. hartwegii (10.1 [+ or -] 0.28 Mg C x [ha.sup.-1]). Thus, the litter layer in the A. jorullensis system had markedly the shortest residence time (8 years), suggesting high rates of litter decomposition. The soil carbon stock (at soil depth of 1 m) was greater in A. jorullensis (189 Mg C x [ha.sup.-1]) and P. hartwegii (137 Mg C x [ha.sup.-1]) than in A. religiosa (68 Mg C x [ha.sup.-1]). The A. religiosa and A. jorullensis systems had the highest and lowest total ecosystem C content (301 and 228 Mg C x [ha.sup.-1], respectively). Upward migration of the A. religiosa system in response to global climate change, however, could cause losses by 2030 of 187 Mg C x [ha.sup.-1] associated with aboveground biomass. Key words: biomass and carbon stocks, elevational gradient, vegetation-soil systems, temperate forest. Les systemes que forment le sol et la vegetation influencent differemment les processus de l'ecosysteme relies au cycle du carbone, particulierement lorsqu'une espece d'arbre domine de vastes etendues geographiques soumises aux changements climatiques. L'objectif de cette etude consistait a quantifier les stocks de carbone de l'ecosysteme dans trois systemes solvegetation le long d'un gradient d'elevation sur les hautes terres dans le centre du Mexique. Les systemes sol-vegetation, de la plus basse a la plus haute elevation, etaient domines respectivement par Alnus jorullensis Kunth, Abies religiosa (Kunth) Schltdl. & Cham. et Pinus hartwegii Lindl. La biomasse aerienne et souterraine des arbres a ete determinee dans chaque systeme, ainsi que la litiere, les debris ligneux grossiers, les racines et la chute de litiere. Le systeme associe a A. religiosa avait le plus important stock de carbone (216 [+ or -] 31 Mg C x [ha.sup.-1]) issu de la biomasse aerienne. Le systeme associe a A. jorullensis avait la plus forte production de chute de litiere (3,1 [+ or -] 0,08 Mg x [ha.sup.-1] x [an.sup.-1]). Cependant, la teneur en carbone de cette couche de litiere (1,2 [+ or -] 0,32 Mg C x [ha.sup.-1]) etait plus faible que celle de P. hartwegii (10,1 [+ or -]0,28 Mg C x [ha.sup.-1]). Par consequent, la couche de litiere du systeme associe a A. jorullensis avait le temps de residence nettement le plus court (8 ans), ce qui correspond a un taux eleve de decomposition. Le stock de carbone dans le sol (jusqu'a une profondeur de 1 m) etait plus eleve dans les systemes associes a A. jorullensis (189 Mg C x [ha.sup.-1]) et P. hartwegii (137 Mg C x [ha.sup.-1]) que dans le systeme associe a A. religiosa (68 Mg C x [ha.sup.-1]). Les systemes associes a A. religiosa et A. jorullensis avaient la teneur en C total de l'ecosysteme respectivement la plus elevee et la plus faible (301 et 228 Mg C x [ha.sup.-1]). Cependant, la migration vers le haut du systeme associe a A. religiosa en reaction aux changements climatiques planetaires pourrait vers 2030 entrainer des pertes de 187 Mg C x [ha.sup.-1] associees a la biomasse aerienne. [Traduit par la Redaction] Mots-cles : biomasse et stocks de carbone, gradient d'elevation, systemes sol-vegetation, foret temperee., 1. Introduction The effect of plant species on ecosystem processes depends on their physiology and ecology and their interaction with climate and soil (Binkley 1995; Chapin et al. 2011; Augusto [...]

Mexican temperate forests, at the southernmost end of the distribution range of this ecosystem, are the world's centre of diversity of pine and oak, with 55 and 161 species, respectively. Such forests are threatened by land-use change, unsustainable forest management practices, and climate change; these threats reduce their diversity, alter the distribution ranges of species, modify disturbance regimes, and reduce ecosystem adaptability. This paper briefly reviews (i) the ecology of the Mexican temperate forests, (ii) the ecological basis for the unique diversity of pine and oak species, (iii) the main disturbances as well as the main drivers of global changes affecting these forests, in particular climate change, and (iv) the social, economic, and cultural factors to be considered in proposing a new forest management approach. It proposes a new conceptual framework to manage Mexican temperate forests that are in line with (i) their natural dynamics, (ii) the rapidly changing and uncertain global environmental, social, and economic conditions, and (iii) the complex adaptive system approach. This new forest management combines functional zoning, multispecies plantations, and sylvicultural interventions to increase the adaptive capacity of forests as a way to balance the increasing need for timber products with the need for other ecosystem services facing rapidly changing and uncertain future environmental, social, and economic conditions. Key words: adaptability, biodiversity, climate change, disturbances, fire regime, forest income. Les forets temperees mexicaines, situees a l'extreme sud de l'aire de repartition de cet ecosysteme, sont le centre mondial de la diversite de pins et de chenes comptant 55 et 161 especes, respectivement. Ces forets sont menacees par la facon dont elles sont utilisees, par des pratiques de gestion de forets non durable et du au changement climatique; ces menaces reduisent leur diversite, modifient les aires de repartition des especes, modifient les regimes de perturbations et reduisent l'adaptabilite de l'ecosysteme. Cet article examine brievement (i) l'ecologie des forets temperees mexicaines, (ii) la base ecologique de la diversite unique d'especes de pins et de chenes, (iii) les principales perturbations ainsi que les principaux moteurs des changements globaux qui affectent ces forets, en particulier le changement climatique, et (iv) les facteurs sociaux, economiques et culturels, a prendre en consideration, en proposant une nouvelle approche de la gestion forestiere. Cet article propose un nouveau cadre conceptuel pour gerer les forets temperees mexicaines conforme avec (i) leur dynamique naturelle, (ii) les conditions environnementales, sociales et economiques globales, en changement continuel et incertaines, et (iii) l'approche adaptative du systeme complexe. Cette nouvelle gestion forestiere combine un zonage fonctionnel, des plantations multi-especes et des interventions sylvicoles pour augmenter la capacite d'adaptation des forets afin d'equilibrer la necessite croissante des produits forestiers avec la necessite de d'autres services ecosystemiques exposes a des conditions environnementales, sociales et economiques qui sont en changement continuel et incertaines. Mots-cles: adaptabilite, biodiversite, changement climatique, perturbations, regime de feu, revenu de la foret., Mexican temperate forests Mexican temperate forest ecosystems include single-species or mixed forests of pine (Pinus spp.), oak (Quercus spp.), and many other genera such as Abies, Pseudotsuga, Picea, Cupressus, and [...]

Sustainable silvicultural management requires the maintenance of long-term ecosystem processes. We used the CENTURY model to simulate the impact of wood extraction and organic amendments on aboveground biomass, carbon (C) storage, and the availability of nitrogen (N) in the two dominant silvicultural methods in Mexico: the silvicultural development method (SDM) and irregular forest management (IFM). The values of the mean absolute percentage error for the SDM and IFM were 2.1% and 3.3% for C in aboveground biomass, 5.7% and 5.0% for soil organic carbon (SOC), and 14.9% and 21.6% for N, respectively. Simulation for the SDM (1967–2068) suggested a reduction of ~7% in C in soil, microbial biomass, and litter, 9% in aboveground biomass C, and ~20% in the mineral N available. For IFM, the simulation (2009–2019) suggested a reduction of 14% in the accumulation of aboveground biomass and 13% in the mineral N available. Simulation of the adoption of management practices suggested that N mineral availability would increase by 2%–3% without drastically reducing the SOC, improving aboveground biomass production by ~7%, in each management system. Study Implications In Mexico, current silvicultural management is causing alterations in the biological and chemical processes of the soil, but the future impacts on the production of forest wood and loss of fertility cannot be estimated by direct measurements. We simulated two silvicultural management alternatives with two rotation cycles and measured the response in terms of SOC, nitrogen availability, and aboveground biomass. The model shows that improving forest residue management by adding organic amendments to the soil would counteract changes in soil microbial activity, nitrogen availability, SOC, and aboveground biomass in the future. Managers should consider this information to reorient current crop residue management to achieve the objectives and the sustainability of forest management in Mexican temperate forests. [ABSTRACT FROM AUTHOR]

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