Richness and abundance of granivorous vertebrates determine acorn removal patterns in a human modified oak forest

Most forests of the Earth have been affected by human activities and this can alter the plant-animal interactions on which depend the functional integrity of these ecosystems. In this study, we assessed the relationships between acorn removal rates and the richness and abundance of granivorous vertebrates along a forest-edge-clearing gradient. We also evaluated whether removal rates differed among oak species with different acorn size. To this purpose, a field experiment was performed including acorns of five oak species, which were exposed to seed consumers in the three different habitats (forest interior, man-made clearings and the edge between these habitats). The experimental units consisted in five paper trays containing 50 acorns of each oak species located at different distances from the edge towards the forest and the man-made clearing (0, 20 and 50 m). Experimental sites were equipped with phototraps to record the identity of the visiting granivorous vertebrates. Richness and abundance of granivores increased from the edge towards the forest interior, while the converse patterns were observed in the man-made clearing. For most oak species, acorn removal patterns was positively correlated with richness and abundances of granivores, though in all habitats small-sized acorns were removed much faster and in larger proportions than big-sized acorns. Although these results are specific for the study site, they suggest that man-made clearings reduce the richness and abundance of granivores, thus negatively affecting the secondary dispersion of zoochoric tree species towards open habitats. Further, it also seems that large-seeded oak species face greater dispersal limitations than small-seeded oaks, because of the lack of animals able to scatter them from the forest to the clearings

Restauración de bosques de encinos: entendiendo los factores que inhiben su regeneración

VII Congreso Mexicano de Ecología. Lugar y fecha de celebración: Juriquilla, Santiago de Querétaro (México), 29 septiembre-4 octubre 201

Restoration interventions produce opposite and non-additive benefits on tree establishment in degraded forest clearings

9 páginas.- 3 figuras.- 1 tabla.- 75 referencias.- Supporting Information may be found in the online version of this article https://doi.org/10.1111/rec.13539The natural regeneration of forests is declining in human-modified landscapes and overcoming ecological barriers to the seedling establishment is paramount to its restoration. This study focus on two common forest regeneration barriers: excessive sun exposure and low-quality soils. A degraded clearing with eroded and compacted soils within a disturbed oak forest in Mexico was chosen, and 20 experimental plots in a randomized factorial block design were set up to test seedling performance in the artificial shade and in forest topsoil that was transferred from a nearby remnant forest, as well as a combination of both. We sowed 400 acorns from two oak species (Quercus eduardii and Q. viminea) and monitored the emerging seedlings for 63 months. Our results confirm different survival and growth rates between species, ontogenetic stages, and environmental micro-conditions. The effect of artificial shade on seedling performance was positive in weathered soil but negative or neutral in transferred forest soil. Restoration interventions did not have additive benefits; seedling performance was improved by both restoration interventions applied separately though was not further enhanced when both actions were combined. Both species had different mechanisms to cope with water stress, which resulted in different photosynthetic rates under full sun. Trade-offs resulted in different life stages that were more enhanced by different restoration strategies; survival and growth were most enhanced by applying artificial shade or transferring forest topsoil, respectively. Restoration practitioners may prioritize seedling survival in harsh conditions and growth in less severe degraded sites or apply interventions sequentially over time. © 2021 Society for Ecological Restoration.This work was supported by the Secretary of Public Education (SEP) and the National Council for Science and Technology (CONACyT; grants CB-2015-01-257738 to DD and fellowshipno. 574853 to MBRR).Peer reviewe

Bevorderen van deelname en deelnamekansen aan een leven lang leren

Afdeling Sociale pedagogiek en gezinspedagogiek. Centrum voor Sociale en beroepspedagogiek. Centrum voor Permanente vorming in beroepen en organisaties (CPVBO) Hoger instituut voor de Arbeid (HIVA) Departement Pedagogische wetenschappen.status: publishe

Human impact of wild firewood species in the Rural Andes community of Apillapampa, Bolivia

Firewood is the basic fuel source in rural Bolivia. A study was conducted in an Andean village of subsistence farmers to investigate human impact on wild firewood species. A total of 114 different fuel species was inventoried during fieldtrips and transect sampling. Specific data on abundance and growth height of wild firewood species were collected in thirty-six transects of 50 x2 m(2). Information on fuel uses of plants was obtained from 13 local Quechua key participants. To appraise the impact of fuel harvest, the extraction impact value (EIV) index was developed. This index takes into account local participants' appreciation of (1) decreasing plant abundance; (2) regeneration capacity of plants; (3) impact of root harvesting; and (4) quality of firewood. Results suggest that several (sub-)woody plant species are negatively affected by firewood harvesting. We found that anthropogenic pressure, expressed as EIV, covaried with density of firewood species, which could entail higher human pressure on more abundant and/or more accessible species. The apparent negative impact of anthropogenic pressure on populations of wild fuel species is corroborated by our finding that, in addition to altitude, several anthropogenic variables (i.e. site accessibility, cultivation of exotics and burning practices) explain part of the variation in height of firewood species in the surroundings of Apillapampa