Background Studying motives of plant management allows understanding processes that originated agriculture and current forms of traditional technology innovation. Our work analyses the role of native plants in the Ixcatec subsistence, management practices, native plants biocultural importance, and motivations influencing management decisions. Cultural and ecological importance and management complexity may differ among species according with their use value and availability. We hypothesized that decreasing risk in availability of resources underlies the main motives of management, but curiosity, aesthetic, and ethical values may also be determinant. Methods Role of plants in subsistence strategies, forms of use and management was documented through 130 semi-structured interviews and participant observation. Free listing interviews to 38 people were used to estimate the cognitive importance of species used as food, medicine, fuel, fodder, ornament and ceremonial. Species ecological importance was evaluated through sampling vegetation in 22 points. Principal Components Analysis were performed to explore the relation between management, cultural and ecological importance and estimating the biocultural importance of native species. Results We recorded 627 useful plant species, 589 of them native. Livelihood strategies of households rely on agriculture, livestock and multiple use of forest resources. At least 400 species are managed, some of them involving artificial selection. Management complexity is the main factor reflecting the biocultural importance of plant species, and the weight of ecological importance and cultural value varied among use types. Management strategies aim to ensure resources availability, to have them closer, to embellish human spaces or satisfying ethical principles. Conclusion Decisions about plants management are influenced by perception of risk to satisfy material needs, but immaterial principles are also important. Studying such relation is crucial for understanding past and present technological innovation processes and understand the complex process of developing biocultural legacy.

Makaleyi görüntüle

Background Worldwide, mestizo communities' ethnobotanical knowledge has been poorly studied. Based on a mestizo group in Mexico, this study assesses a) the use value (UV) of the local flora, b) gendered differences in plant species, and c) the association between socio-economic variables and ethnobotanical knowledge. Methods To assess the degree of knowledge of plant resources, we conducted 41 interviews collecting information on knowledge of local plant resources and the socio-economic situation of the informant. We also collected free listings of useful plants by category of use to identify the UV of each species. With the support of key informants, we photographed and collected the plant material recorded during the interviews and free listings on five different habitats. Paired t-tests and a Wilcoxon signed rank test were used to determine differences in the number of species known by men and women. Differences in distribution were analyzed by means of the Shapiro-Wilk's W normality tests. To determine the association of socio-economic factors and ethnobotanical knowledge, we used a non-metric multidimensional scaling analysis (NMDS). Results Informants listed 185 species. Medicinal plants constituted the most diverse group (90 species). Tropical deciduous forest is the habitat that concentrates the highest proportion of plant resources (80 species). The use-values were classified into three groups: A (4-6 UV; three species), B (0.35-1.37 UV; 39 species) and C (0-0.29 UV; 143 species). High-quality wood species and those associated to religious ceremonies had the highest UV. Women's and men's knowledge of plant species showed statistically significant differences at the interspecific and the intracategorical levels (Student's test, T15 = 4.8, p Conclusion This research improves our understanding of the socio-economic activities associated with the intracultural distribution of ethnobotanical knowledge among mestizo Mexican communities. It also provides information on plant resources and habitats and how local peasants value them. This information could help in the development of proposals to improve biocultural conservation and strengthen traditional knowledge systems for effective forest management.

Makaleyi görüntüle

Strong covariation between organismal traits is often taken as an indication of a potentially adaptively significant relationship. Because one of the main functions of woody stems is mechanical support, identifying the factors that covary with biomechanics is essential for inference of adaptation. To date in such studies, stem biomechanics is plotted against stem age or size, thus with implicit assumptions regarding the importance of each in determining mechanics. Likewise, comparing ontogenies between individuals is central to the study of ontogenetic evolution (e.g., heterochrony). Both absolute age and size have been used, but the rationale for choosing one over the other has not been examined. Sampling a plant of simple architecture across microsites with differing sizes for the same absolute age, we compared regressions of stem length, mechanics, and tissue areas against age and size. Stem length was predicted by diameter but not by age, and stem biomechanics and tissue areas were better explained by stem length rather than age. We show that the allometric and mechanical properties observed across microsites are uniform despite great plasticity in other features (e.g., size and wood anatomy) and suggest that this uniformity is an example of developmental homeostasis. Finally, we discuss reasons for preferring size over absolute age as a basis for comparing ontogenies between individuals.

Makaleyi görüntüle

Edible insects are a natural renewable resource that provides food to many ethnic groups in Mexico. Some of these species are overexploited because of increased consumption, caused by the huge human population growth in the area and because of the large demand of these insects from many restaurants in Mexico and in other countries. In Tulancalco, a small arid village in the State of Hidalgo, I carried out studies on edible insects over 25 years. The inhabitants of this village have a natural economy and use some 30 species of insects as food. At present, we have noticed a decrease in the population of several species due to overexploitation, which is carried by non-qualified independent workers who are not natives of the town. These gatherers sell their catch to make a living, thus contributing to the socioeconomic factors associated with this issue. These actions have degraded the ecosystems of this area, and consequently the prevention of these measures is critical. The study species in this paper include 14 threatened species and we discuss some pragmatic measures that could implemented to avoid their extinction. In addition, some actions for the preservation of the ethnoentomobiodiversity in the area are proposed.

Makaleyi görüntüle

Diurnal variation in leaf stomatal conductance (gs) of three xerophilous species (Buddleia cordata, Senecio praecox and Dodonaea viscosa) was measured over a 10-month period during the dry and wet seasons in a shrubland that is developing in a lava substratum in Mexico. Averaged stomatal conductances were 147 and 60.2 (B. cordata), 145 and 24.8 (D. viscosa) and 142.8 and 14.1 mmol m(-2) s(-1) (S. praecox) during the wet and dry season respectively. Leaf water potential (Psi) varied in a range of -0.6 to -1.2 (S. praecox), -0.6 to -1.8 (B. cordata) and -0.9 to -3.4 MPa (D. viscosa) during the same measurement periods. Stomata were more sensitive to changes in irradiance, air temperature and leaf-air vapour pressure difference in the rainy season than the dry season. Although stomatal responses to Psi were difficult to distinguish in any season (dry or rainy), data for the entire period of measurement showed a positive correlation, stomata tending to open as Psi increased, but there is strong evidence of isohydric behaviour in S. praecox and B. cordata. A multiplicative model relating gs to environmental variables and to Psi accounted for 79%-83% of the variation of gs in three sites (pooled data); however, the performance of the model was poorer (60%-76%) for individual species from other sites not included in the pooled data.

Makaleyi görüntüle