Habitat fragmentation threatens biodiversity worldwide, particularly affecting large-bodied species that require vast territories and move across long distances, including most large felids. The jaguar Panthera onca has lost more than half of its habitat throughout its range and its subpopulations are becoming isolated, making them susceptible to local extinction. Knowledge about the status of its subpopulations in highly fragmented environments is lacking but urgently needed. Using camera traps during 2019–2020, we estimated number of individuals, age classes and sex ratio, occupancy, relative abundance and density of jaguars in Nayarit, western Mexico. We also determined the relative abundance of potential prey and estimated the land-cover change rate during 1999–2019, using GIS. We found that a resident subpopulation of five adult females, two adult males and one cub, at a high density (5.3 individuals/100 km²), is supported by at least 14 wild prey species. Natural habitat in the area is rapidly decreasing because of expanding agriculture and shrimp farming: agricultural areas increased from 39 to 50% and mangroves decreased from 35 to 26% of the study area over 20 years. The high jaguar population density and the diversity and relative abundance of remaining wild prey are remarkable, considering that natural habitat in the area is highly fragmented, shrinking rapidly and embedded in a matrix of human-dominated land-cover types. Effective conservation actions are needed urgently, including the protection of patches with native vegetation, reforestation to maintain connectivity between these patches, and the involvement of local communities.

Background: Nowadays there is a need to implement novel and effective methods in sustainable agriculture. Arbuscular mycorrhizal (AM) fungi are an alternative that benefits crop productivity and reduces the use of chemical inputs. Question: Have commercial and native mycorrhizal inoculants the same infectivity? Is the performance of maize seedlings affected by commercial and native inoculum type? Study species: Maize (Zea mays). Study site and dates: Greenhouse experiment, March 2016. Methods: The experimental design was unifactorial (five levels) and completely randomized: four mycorrhizal inocula (liquid, liquid mix, solid, and native AM spores), and one control (NM- inoculum). After a month of inoculating the seedlings, we harvested the plants, and the biomass and AM colonization were evaluated. Results: The seedlings without AM fungi had greater total above- and belowground biomass compared with the inoculated seedlings. Only native and solid fungus treatments showed AM colonization in their roots. Our results are discussed in terms of soil mineral nutrient concentrations, cost-benefit of mycorrhizal symbiosis, edaphic origin of AM-native and contained of commercial inocula. Conclusions: The infectivity and effectiveness observed in the maize seedlings depends of mycorrhizal inoculum type.

Many of Mexico’s mature tropical forests are immersed in a complex landscape with agricultural fields, second-growth vegetation, and forest fragments; assemblages of frugivorous birds vary in these different landscape elements. We studied assemblages of birds feeding on fruits of three tree species in continuous forest, vegetation corridors, isolated forest fragments, and secondary vegetation. Through direct observation of focal trees and documentation of frugivorous feeding activities, we use effective species numbers and Non-Metric Multidimensional Scaling to describe the variation of habitat use patterns between assemblages. We recorded 1162 individuals of 57 bird species feeding on ripe fruits of Nectandra salicifolia, Dendropanax arboreus, and Bursera simaruba. Thirty-two species fed on isolated fragments and corridors of vegetation; our analysis grouped these two landscape elements by their species composition, representing 64.6% of all recorded individuals. The composition of the assemblages was influenced by the availability of fruits; Bursera simaruba exhibited a prolonged fruiting period and attracted a wider range of consumer species. Although the number of species varied slightly between different elements of the landscape, the importance of corridors and isolated forest fragments was key to the connectivity between bird and tree populations. At the geographic scale of this study, the transformation of the area does not reduce the diversity of frugivorous bird assemblages, as a result of the connectivity between the different elements of the landscape.

Background: Domestication-driven shifts to a relatively more acquisitive strategy and increased biomass allocation in plant organs have been demonstrated in some major crops. However, the extent to which this pattern is influenced by the relatively more resource-rich conditions prevailing in agroecosystems is less clear. Although soil is the main source of nutrients for plants, it remains unknown if the effect of domestication on resource-use strategy and biomass allocation patterns is contingent upon soil origin. Hypothesis: The effects of domestication and soil origin on the resource-use strategy and biomass allocation are not additive. Studied species Chaya (Cnidoscolus aconitifolius I.M. Johnst.). Methods: The effects of domestication (wild vs. domesticated plants) and soil origin (forest, homegardens, and intensive orchards) on leaf traits associated with the leaf economic spectrum and biomass allocation to above- and below-ground organs were assessed experimentally. Results: A domestication-driven shift to a relatively more acquisitive strategy was found. This effect was contingent upon soil origin. Domesticated plants reverted to a more conservative strategy when they were grown in forest soil. Increased biomass allocation and decoupling among different organs were observed in domesticated plants. Leaf production and the root:shoot ratio were also contingent upon soil origin, with greater values observed when domesticated chaya was grown in orchard soil. Conclusions: This study supports the existence of an intraspecific leaf economic spectrum in chaya. While domestication, as a main effect, tends to shift the resource-use strategy to the acquisitive side of the spectrum, this effect is clearly contingent upon the soil origin.

Background . The ability of weeds to thrive in the stressful environments created by human disturbance has been explained mainly by a set of life history traits, such as short life cycles, generalist habits, as well as early and sustained reproduction. However, the evidence that these traits are better represented in weeds than in related species of other environments is mixed. To explore the relationship between weeds and the life history traits, we used the fact that plants are weedy to different degrees because of the heterogeneous nature of environments produced by disturbance. In a group of four congeners, we studied some growth and reproduction parameters in relation to the degree of synanthropy of the species, determined previously. Methods. In a common garden experiment, we compared relative growth rate, time to flowering, and biomass distribution between four species of the genus Melampodium (Asteraceae) that are weedy to different degrees. Results. The most synanthropic species, M. divaricatum , stood out for its steady growth rate, but not for assigning more resources to reproduction, nor for early flowering. In general, we found no association between growth and reproductive parameters studied in the four Melampodium species and the degree to which they are weeds. Conclusions. Results suggest that traits such as fast growth and early reproduction may not be essential for life as a weed. Rather, weedy species exhibit a complex pattern of growth traits that could be affected by conditions independent of anthropogenic disturbance.