Alfaro Reyna T., Retana J., Martínez-Vilalta J. (2018) Is there a substitution of Pinaceae by Fagaceae in temperate forests at the global scale?. Global and Planetary Change. 166: 41-47.LinkDoi: 10.1016/j.gloplacha.2018.04.001
Reports on forest decline, changes in species composition and the distribution of forests in response to changes in climate and land use are increasing worldwide. Temperate forests are largely dominated by two tree families: Pinaceae and Fagaceae. These two families have distinct functional properties and different responses to environmental factors. Several local and regional assessments, particularly in Europe, have found that species of Fagaceae are invading areas previously dominated by Pinaceae. The main aim of this synthesis study is to analyze the relative dynamics of Pinaceae and Fagaceae species in temperate forests around the world, with the following specific objectives: (1) establish if there is a consistent directional substitution of Pinaceae by Fagaceae worldwide; and (2) determine whether these directional changes are associated with specific climatic conditions or certain geographic regions, reflecting differences in historical forest management and land use. A bibliographic review was performed and 51 papers were found that met the search criteria, including a total of 121 case studies in which the relative dynamics of Pinaceae and Fagaceae were evaluated. Our results show that the relative abundance of Fagaceae increased in 71% of cases (P → F dynamics), whereas Pinaceae relative abundance increased in 17% of cases (F → P) and 12% of cases did not show clear changes. Increases of Fagaceae relative to Pinaceae were less clear in areas where vegetation dynamics were driven by natural disturbances. Our results indicate a widespread increase in dominance of Fagaceae species at the expense of Pinaceae across northern temperate forests, with the exception of Eastern North America. The potential implications for ecosystem function and forest resilience under ongoing climate change are large and clearly deserve further study. © 2018 Elsevier B.V.
Arasa-Gisbert, R., Vayreda, J., Román-Cuesta, R.M., Villela, S.A., Mayorga, R., Retana, J. (2018) Forest diversity plays a key role in determining the stand carbon stocks of Mexican forests. Forest Ecology and Management. 415-416: 160-171.LinkDoi: 10.1016/j.foreco.2018.02.023
Arnan X., Andersen A.N., Gibb H., Parr C.L., Sanders N.J., Dunn R.R., Angulo E., Baccaro F.B., Bishop T.R., Boulay R., Castracani C., Cerdá X., Toro I.D., Delsinne T., Donoso D.A., Elten E.K., Fayle T.M., Fitzpatrick M.C., Gómez C., Grasso D.A., Grossman B.F., Guénard B., Gunawardene N., Heterick B., Hoffmann B.D., Janda M., Jenkins C.N., Klimes P., Lach L., Laeger T., Leponce M., Lucky A., Majer J., Menke S., Mezger D., Mori A., Moses J., Munyai T.C., Paknia O., Pfeiffer M., Philpott S.M., Souza J.L.P., Tista M., Vasconcelos H.L., Retana J. (2018) Dominance–diversity relationships in ant communities differ with invasion. Global Change Biology. 24: 4614-4625.LinkDoi: 10.1111/gcb.14331
The relationship between levels of dominance and species richness is highly contentious, especially in ant communities. The dominance-impoverishment rule states that high levels of dominance only occur in species-poor communities, but there appear to be many cases of high levels of dominance in highly diverse communities. The extent to which dominant species limit local richness through competitive exclusion remains unclear, but such exclusion appears more apparent for non-native rather than native dominant species. Here we perform the first global analysis of the relationship between behavioral dominance and species richness. We used data from 1,293 local assemblages of ground-dwelling ants distributed across five continents to document the generality of the dominance-impoverishment rule, and to identify the biotic and abiotic conditions under which it does and does not apply. We found that the behavioral dominance–diversity relationship varies greatly, and depends on whether dominant species are native or non-native, whether dominance is considered as occurrence or relative abundance, and on variation in mean annual temperature. There were declines in diversity with increasing dominance in invaded communities, but diversity increased with increasing dominance in native communities. These patterns occur along the global temperature gradient. However, positive and negative relationships are strongest in the hottest sites. We also found that climate regulates the degree of behavioral dominance, but differently from how it shapes species richness. Our findings imply that, despite strong competitive interactions among ants, competitive exclusion is not a major driver of local richness in native ant communities. Although the dominance-impoverishment rule applies to invaded communities, we propose an alternative dominance-diversification rule for native communities. © 2018 John Wiley & Sons Ltd
Gibb H., Sanders N.J., Dunn R.R., Arnan X., Vasconcelos H.L., Donoso D.A., Andersen A.N., Silva R.R., Bishop T.R., Gomez C., Grossman B.F., Yusah K.M., Luke S.H., Pacheco R., Pearce-Duvet J., Retana J., Tista M., Parr C.L. (2018) Habitat disturbance selects against both small and large species across varying climates. Ecography. 41: 1184-1193.LinkDoi: 10.1111/ecog.03244
Global extinction drivers, including habitat disturbance and climate change, are thought to affect larger species more than smaller species. However, it is unclear if such drivers interact to affect assemblage body size distributions. We asked how these two key global change drivers differentially affect the interspecific size distributions of ants, one of the most abundant and ubiquitous animal groups on earth. We also asked whether there is evidence of synergistic interactions and whether effects are related to species’ trophic roles. We generated a global dataset on ant body size from 333 local ant assemblages collected by the authors across a broad range of climates and in disturbed and undisturbed habitats. We used head length (range: 0.22–4.55 mm) as a surrogate of body size and classified species to trophic groups. We used generalized linear models to test whether body size distributions changed with climate and disturbance, independent of species richness. Our analysis yielded three key results: 1) climate and disturbance showed independent associations with body size; 2) assemblages included more small species in warmer climates and fewer large species in wet climates; and 3) both the largest and smallest species were absent from disturbed ecosystems, with predators most affected in both cases. Our results indicate that temperature, precipitation and disturbance have differing effects on the body size distributions of local communities, with no evidence of synergistic interactions. Further, both large and small predators may be vulnerable to global change, particularly through habitat disturbance. © 2017 The Authors
Lecina-Diaz J., Alvarez A., Regos A., Drapeau P., Paquette A., Messier C., Retana J. (2018) The positive carbon stocks–biodiversity relationship in forests: co-occurrence and drivers across five subclimates. Ecological Applications. 28: 1481-1493.LinkDoi: 10.1002/eap.1749
Carbon storage in forests and its ability to offset global greenhouse gas emissions, as well as biodiversity and its capacity to support ecosystem functions and services, are often considered separately in landscape planning. However, the potential synergies between them are currently poorly understood. Identifying the spatial patterns and factors driving their co-occurrence across different climatic zones is critical to more effectively conserve forest ecosystems at the regional level. Here, we integrated information of National Forest Inventories and Breeding Bird Atlases across Europe and North America (Spain and Quebec, respectively), covering five subclimates (steppe, dry Mediterranean, humid Mediterranean, boreal, and temperate). In particular, this study aimed to (1) determine the spatial patterns of both forest carbon stocks and biodiversity (bird richness, tree richness, and overall biodiversity) and the factors that influence them; (2) establish the relationships between forest carbon stocks and biodiversity; and (3) define and characterize the areas of high (hotspots) and low (coldspots) values of carbon and biodiversity, and ultimately quantify their spatial overlap. Our results show that the factors affecting carbon and biodiversity vary between regions and subclimates. The highest values of carbon and biodiversity were found in northern Spain (humid Mediterranean subclimate) and southern Quebec (temperate subclimate) where there was more carbon as climate conditions were less limiting. High density and structural diversity simultaneously favored carbon stocks, tree, and overall biodiversity, especially in isolated and mountainous areas, often associated with steeper slopes and low accessibility. In addition, the relationship between carbon stocks and biodiversity was positive in both regions and all subclimates, being stronger where climate is a limiting factor for forest growth. The spatial overlap between hotspots of carbon and biodiversity provides an excellent opportunity for landscape planning to maintain carbon stocks and conserve biodiversity. The variables positively affecting carbon and biodiversity were also driving the hotspots of both carbon and biodiversity, emphasizing the viability of “win-win” solutions. Our results highlight the need to jointly determine the spatial patterns of ecosystem services and biodiversity for an effective and sustainable planning of forest landscapes that simultaneously support conservation and mitigate climate change. © 2018 by the Ecological Society of America
Vilà-Cabrera, A., Coll, L., Martínez-Vilalta, J., Retana, J. (2018) Forest management for adaptation to climate change in the Mediterranean basin: A synthesis of evidence. Forest Ecology and Management. 407: 16-22.LinkDoi: 10.1016/j.foreco.2017.10.021
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