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Functional diversity is related to the maintenance of processes and functions in ecosystems. However, there is a lack of a conceptual framework that highlights the application of functional diversity as an ecological indicator. Therefore, we present a new initiative for motivating the development of ecological indicators based on functional diversity. We are interested in showing the challenges and solutions associated with these indicators. We integrated species assemblage theories and literature reviews. We considered plant traits related to ecosystem processes and functions (specific leaf area, leaf dry matter content, wood density, phenology, and seed mass) to show the application of a selection of functional diversity metrics that can be used as ecological indicators (i.e., community weighted-mean, functional divergence, functional richness and functional evenness). We caution that functional diversity as an ecological indicator can be misinterpreted if species composition is unknown. Functional diversity values can be over-represented by weed species (species established in disturbed sites) and do not maintain original processes and functions in ecosystems. Therefore, we searched for evidence to demonstrate that weed species are ecological indicators of functional diversity changes. We found support for two hypotheses that explain the effect of weed species on ecosystem function: functional homogenization, and functional transformation. Likewise, we showed the application of some tools that can help study anthropogenic effects on functional indicators. This perspective shows that the paradigm of addressing the effects of disturbances on ecosystem processes by using functional diversity as an ecological indicator can improve environmental evaluation, particularly in areas affected by human activities. Key words: weed species, leaf traits, seed mass, wood density, fruit and flower traits. La diversite fonctionnelle est liee au maintien des processus et des fonctions dans les ecosystemes. Cependant, il manque un cadre conceptuel qui mette en evidence l'application de la diversite fonctionnelle comme indicateur ecologi-que. Par consequent, les auteurs presentent une nouvelle initiative pour motiver le developpement d'indicateurs ecologi-ques bases sur la diversite fonctionnelle. Ils souhaitent montrer les defis et les solutions associes a ces indicateurs. Ils ont integre des theories sur les assemblages d'especes et des analyses documentaires. Ils ont pris en compte les traits des plantesliesaux processus et aux fonctionsdes ecosystemes(surface foliaire specifique, teneur en matiere seche des feuilles, densite du bois, phenologie et masse des graines) pour montrer l'application d'une selection de mesures de la diversite fonctionnelle qui peuvent etre utilisees comme indicateurs ecologiques (c'est-a-dire la moyenne ponderee de la commu-naute, la divergence fonctionnelle, la richesse fonctionnelle et la regularite fonctionnelle). Ils mettent en garde contre le fait que la diversite fonctionnelle en tant qu'indicateur ecologique peut etre mal interpretee si la composition en especes est inconnue. Les valeurs de diversite fonctionnelle peuvent etre surrepresentees par les especes adventices (especes eta-blies dans des sites perturbes) et ne permettent pas de maintenir les processus et les fonctions d'origine des ecosystemes. Ainsi, ils ont cherche des preuves demontrant que les especes adventices sont des indicateurs ecologiques des changements de la diversite fonctionnelle. Ils ont trouve un appui pour deux hypotheses qui expliquent l'effet des especes adventices sur la fonction de l'ecosysteme : l'homogeneisation fonctionnelle et la transformation fonctionnelle. De meme, ils ont montre l'application de certains outils qui peuvent aider a etudier l'effet anthropique sur les indicateurs fonctionnels. Cette syn-these montre que le paradigme consistant a etudier les effets des perturbations sur les processus ecosystemiques en uti-lisant la diversite fonctionnelle comme indicateur ecologique peut ameliorer l'evaluation environnementale, en particulier dans les zones affectees par les activites humaines. [Traduit par la Redaction] Mots-cles: especes adventices, traits foliaires, masse des graines, densite du bois, traits des fruits et des fleurs., Introduction At the global level, the implementation of ecological indicators for environmental evaluation and ecosystem conservation has expanded (LaPaix et al. 2009; Tyler et al. 2021). Ecological indicators are quantitative [...]

Climate change projections suggest a precarious future for the Monarch butterfly (Danaus plexippus) as the suitable climatic habitat of its exclusive overwintering host Abies religiosa (oyamel, Sacred fir, a conifer endemic to Mexico) inside the Monarch Butterfly Biosphere Reserve (MBBR) is expected to disappear by 2090. Since the upper elevation limit of A. religiosa is approximately 3,500 m and the summits of mountains within the MBBR are ca. 3,550 m, we tested the feasibility of establishing A. religiosa at four locations outside its current geographic range in the MBBR, on a geographically close volcano, Nevado de Toluca at 4000 (timberline, an extreme site), 3,800, and 3,600 m (to test species range expansion upward in elevation), and at 3400 m (a reference site, slightly lower than the upper elevation limit of A. religiosa). Using existing shrubs as nurse plants to protect the seedlings from extreme temperatures, at each site we planted five to eight populations, originating between 3,100 and 3,500 m within the MBBR. After three growing seasons in the field (6 years after sowing), we found that: (a) survival and height increment declined steeply with test site elevation; (b) even at the highest sites (3,800 and 4,000 m), survival was acceptable, at 68 and 44%, respectively, although the growth was very poor at 4000 m; (c) populations responded similarly to transfer; (d) transfer effects were best accounted for by annual dryness index; (e) to compensate for the expected 2.3°C increase in mean annual temperature or 0.009 √°Cmm-1 increase of annual dryness index from the reference period (1961-1990) to the decade centered in 2060, it would be necessary to shift populations approximately 500 m to higher elevations; and (f) upward transfers to compensate for the 2.3°C increase in mean annual temperature are expected to result in height increment and survival that are approximately 47 and 21% lower, respectively, than values expected at zero transfer distance. We conclude that the establishment of A. religiosa at 3600 and 3,800 m is feasible and that planted stands could eventually serve as overwintering sites for the Monarch butterfly under projected future climates. [ABSTRACT FROM AUTHOR]

Tropical dry forests (TDFs) are ecosystems of high biocultural value, in which agroforestry systems (AFSs) have been essential in their management and conservation. We aimed to characterize agroforestry practices and analyze their capacity to conserve perennial plant diversity. In addition, we sought to evaluate how the management of TDFs as AFSs, together with their regeneration, influences species diversity and vegetation structure in a landscape with AFSs and TDFs in different conservation states. We compared the species diversity and basal area (BA) of plants in active and fallow AFSs at different regeneration stages in Zacualpan, Colima, Mexico. We found that AFSs harbored 71% of species richness (0D), forming a mosaic that contributed to the gamma diversity (124 species) of TDFs in the area. AFSs supported 23 endemic and 12 protected species. TDFs, active and advanced regeneration AFSs, had the highest number of useful species and diversity. Species richness (0D) in management categories increased as succession progressed, but not the BA, possibly due to frequent browsing and wood and firewood extraction. However, BA may be related to the management of useful trees maintained through agroforestry practices. We suggest increasing the matrix quality through a mosaic of active and fallow AFSs to promote ecological connectivity and biodiversity conservation. [ABSTRACT FROM AUTHOR]

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 Martinez, Picea martinezii T.F. Patt., Picea mexicana Martinez, 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. Key words: climate change, forest genetic resources, forest decline, Mexican conifers, assisted migration, species assemblages. Des symptomes de deperissement de la foret, apparemment attribuable au changement climatique, sont devenus evidents au cours de la derniere decennie dans la cordillere neovolcanique et dans la foret temperee du nord-ouest du Mexique, surtout a la limite xerique (a basse altitude) de plusieurs especes d'arbres. Nous passons en revue et presentons des indices recents d'une infestation massive de Pinus hartwegii Lindl., une espece croissant a la limite de la zone arboree, par le faux-gui Arceuthobium globosum Hawksw. & Wiens et Arceuthobium vaginatum (Humb. & Bonpl. ex Willd.) J.Presl; d'une insuffisance de recrutement de semis d'Abies religiosa (Kunth) Schltdl. & Cham. dans la Reserve de biosphere du papillon monarque; de consanguinite et de defoliation des especes menacees Picea chihuahuana Martinez, Picea martinezii T.F. Patt., Picea mexicana Martinez et des populations de Pseudotsuga menziesii (Mirb.) Franco de l'extreme sud; ainsi que de l'incidence d'epidemies inhabituelles de ravageurs et de maladies (p. ex. Dendroctonus Erichson, 1836 spp., Neodiprion autumnalis Smith et Phytophthora cinnamomi Rands) chez plusieurs especes de chenes et de coniferes. Nous abordons egalement une question difficile dans la discussion : la variation genetique naturelle est-elle suffisante pour engendrer des populations possedant la variation adaptative necessaire pour survivre a la selection naturelle imposee par les scenarios anticipes de changement climatique, ou la plasticite phenotypique sera-t-elle epuisee et les populations declineront-elles? La discussion porte sur la conservation ex situ controversee au sein de zones naturelles protegees, la migration assistee et le deplacement de groupes d'especes en tant qu'options permettant de s'adapter aux impacts anticipes du changement climatique sur les pratiques d'amenagement et de conservation de la foret temperee excessivement biodiversifiee du Mexique. [Traduit par la Redaction] Mots-cles : changement climatique, ressources genetiques forestieres, deperissement de la foret, coniferes mexicains, migration assistee, assemblages d'especes., Introduction Climate change will have an increasing negative impact on Mexican temperate forests. Projections under diverse emission and accumulation scenarios of greenhouse gases suggest that the combination of increased temperature [...]

Few restoration studies have quantified the recovery of the donor meadow. We evaluated the recovery of a monospecific donor meadow of Halodule wrightii, the second most commonly used transplanting species, and assessed the possible effect of 24 plots of 1 m2 placed in an approximately 3,400 m2 large monospecific meadow with a mean cover of 45%, foliar shoot density of 1,280 shoots/m2, and 16 cm canopy height. Extraction densities were 9, 25, 64, and 121 small‐sized extraction cores (4.5 cm diameter, 20 cm depth), with control and procedural control without extractions (N = 4 per treatment). After 6 months, even the plots with the highest extraction densities recovered, as indicated by the shoot number in the extraction areas and seagrass cover in the plots approaching the levels in the controls. The recovery occurred under the environmental conditions: light availability (22,000 ± 51 lx), relatively stable sediments (0.8–1.16 cm) with a fine sandy composition (mean grain diameter, D50: 0.5 ± 0.22 mm), and low organic matter (0.22 ± 0.012%). The recolonization rate was 1–3 shoots per month in the 4.5 cm diameter extraction areas, independent of the extraction level. Thus, approximately 20% of the H. wrightii meadow (corresponding with 121 cores/m2) could be extracted in our study area. This high extraction intensity can be attributed to the adequate selection of donor species, meadow, and size of the planting unit. [ABSTRACT FROM AUTHOR]

The expansion of cattle ranching in the coastal plain of the Gulf of Mexico is transforming freshwater swamps resulting in the reduction of swamps area and the introduction of invasive exotic grasses. This study seeks to determine the structure of the remaining population of Annona glabra in a grassland, evaluate vegetation and environmental conditions of the grassland, and determine the germination capability of A. glabra under different cover conditions of grass growth and two flood levels. The study area is a flooded grassland invaded by Echinochloa pyramidalis in central Veracruz, Gulf of Mexico. In the grassland, we censused and mapped the remaining individuals of A. glabra. We sampled the vegetation and measured the physicochemical characteristics of the soil and water. To evaluate the effect of the invasive grass on the germination of A. glabra seeds, we designed two greenhouse experiments: one (E1) under soil moisture at field capacity and another (E2) under flooded conditions. We found 312 remnant individuals. We recorded 31 plant species, most (72.7%) classified as aquatic/semiaquatic. The relative importance value was highest for E. pyramidalis, Mimosa pigra, and Eleocharis mutata. BEST analysis did not detect significant correlations between vegetation and physicochemical variables, indicating homogeneous environmental conditions. Seed germination was above 80% in E1 and below 20% in E2 in all grass cover levels. Although flooding decreases germination rates, substantial proportion of seeds can germinate, suggesting that natural succession is viable. Based on our results, the flooded grassland has conditions to restore swamp. [ABSTRACT FROM AUTHOR]