Sara Lucía Camargo-Ricalde

Integrative ecological restoration and the involvement of local communities in the Tehuacán-Cuicatlán Valley, Mexico

Restoration ecology is a science focusing on using ecological principles to improve ecosystems degraded usually through habitat destruction (Bradshaw & Chadwik 1980, Handel et al. 1994). Successful ecological restoration depends on negotiation and understanding of different stakeholders, including the daily users of the resources, government institutions that will regulate resource use and the research community working in the area.

Community structure of endemic Mimosa species and environmental heterogeneity in a semi-arid Mexican valley

Abstract In this paper we analyse six communities with seven Mimosa species in the Tehuacán-Cuicatlán valley, Mexico. All species are endemic to Mexico and four are endemic to the valley. Mimosa species are found in (1) the ‘matorral xerófilo’ (arid tropical scrub): Mimosa calcicola, M. lacerata, M. luisana, M. polyantha and M. purpusii, and (2) the ‘selva baja caducifolia’ (tropical deciduous forest): M. adenantheroides, Mimosa texana var. filipes. Most of them occur in similar soil environments, while M. polyantha and M. calcicola establish in particular soil conditions and only M. luisana establishes in two different sites showing a wider range of adaptation to soil characteristics. The communities studied include 24 plant families, 51 genera and ca. 70 species (5% of the total flora estimated in the valley). Heterogeneity was found among the communities. Our results point to the replacement of ‘matorral xerófilo’ and ‘selva baja caducifolia’ by ‘matorral espinoso’ (thorny scrub). Thorny species (e.g. Acacia cochliacantha, Mimosa spp.) are becoming the dominant/codominant elements in the communities. Within the communities, Mimosa species have a significant influence on soil pH, organic matter and electrical conductivity values. These species contribute to ameliorate soil nutrient conditions (OM, Ntot, P, Ca, Mg, Na and K contents) as well as other environmental factors (e.g. temperature, shade) under their canopy in degraded plant communities and may serve as ‘resource islands’. Nomenclature: Dávila et al. (1993); for endemic Mimosa species, see Material and Methods.

Research on arbuscular mycorrhizae in Mexico: an historical synthesis and future prospects

This review analyzes the historical development and advances of the research on arbuscular mycorrhizal fungi (AMF) in Mexico, as well as the prospects for future research. AMF-research has been focused on studying both diversity and functionality in several ecosystems of Mexico, but mainly in the tropical dry and rainy ecosystems, and the agricultural systems. In Mexico, 95 species of AMF have been recorded, representing 41% of the known species worldwide. The functional effects of AMF colonization have been examined in approximately 10% of the known host plants, but greenhouse studies continue to dominate over those conducted under field conditions. Even though research to date has been at the organismic level, further effort is needed due to the high plant diversity in Mexico. Studies on AMF biomass under field conditions and more taxonomic determination are required based on morphological features, biochemical determinations (fatty acids) and molecular tools. In addition, ecophysiological and ecological in situ studies would help in understanding the relationships among AMF, soil fauna, nutrients, and host plants. The contribution of AMF to ecosystemic processes is a priority line of research that requires an integrated approach (inter- and multidisciplinary) in order to define the role of AM symbioses for biogeochemical models. The creation of a Mexican mycorrhizal research network has and will help to identify the main challenges. Generating similar research protocols, and sharing databases and experience will assist mycorrhizologists working under the diverse financial and ecological contexts that is to be found in Mexico and Latin America.

Forestry insularity effect of four Mimosa L. species (Leguminosae-Mimosoideae) on soil nutrients of a Mexican semiarid ecosystem

Information about forestry insularity of plants on soil nutrients will be critical for selecting plant species for agrosilvopastoral or fertility reclamation programs in dry ecosystems. We explored the effects of four Mimosa species (M. lacerata, M. luisana, M. polyantha and M. texana var. filipes) and of rainfall seasonal variation on soil nutrients in a semiarid ecosystem located at the Tehuacán-Cuicatlán Valley, Mexico. Soil samples were taken from outside and under the canopy at three positions (trunk, middle, edge) in all four Mimosa species; ten plants per species. The soil pH, organic matter (SOM), organic carbon (SOC), total nitrogen (Nt), available phosphorus (Pi), and major cations (Ca, Mg, K and Na) were determined. Our results showed that Mimosa species improve the soil under their canopies creating fertile islands with higher SOM, SOC, total N and Pi cycling than the soil in open areas (OA). The insularity effect was significantly species-dependent, where SOM, SOC, Nt and Pi decreased consistently from trunk to OA in all four Mimosa species; however, magnitude varied among species. Likewise, differences in the quantity of soil cations were observed among Mimosa species; though, an insularity gradient trunk-open area was not observed. All these effects were consistent across the species studied and showed little seasonal variability, suggesting a strong forestry insularity of Mimosa species on soil fertility. Of all the four Mimosa species studied, M. lacerata was the most effective in accumulating SOM and nutrients in the soil, for which it would be a good option to implement in agrosilvopastoral or fertility reclamation programs in this semiarid ecosystem.

Traditional Knowledge and Genetic Diversity of Opuntia Pilifera (Cactaceae) in the Tehuacán-Cuicatlán Valley, Mexico

Traditional Knowledge and Genetic Diversity of Opuntia pilifera (Cactaceae) in the Tehuacán-Cuicatlán Valley, Mexico. Economic Botany 59(4)366-376, 2005. Most studies of the genusOpuntia have focused on economically important species, and therefore more knowledge concerning the genetic diversity among wild and locally managedOpuntia species is needed for an expanded use of cacti in the future. The present study is part of ongoing ethnobotanical work in the Tehuacán-Cuicatlán Valley of Mexico and focuses on six traditionally classified forms ofOpuntia pilifera used as food by the indigenous Popoloca people in San Juan Atzingo. Traditional knowledge of how to distinguish these forms based on fruit flavor, color, size, and number of spines on the fruits and cladodes is preserved in the local community. Genetic fingerprinting with 129 AFLPs did not correlate with this traditional morphological classification of 67 cacti. Yet, these AFLPs distinguished the analyzed 67Opuntia pilifera cacti easily from the out-group comprising 17 wildOpuntia velutina.RésuméConocimiento Tradicional y Diversidad Genética de Opuntia piLIfera(Cactaceae) en El Valle de Tehuacán-Cuicatlán, Mexico. La mayoría de los estudios sobre genética de poblaciones del géneroOpuntia (Cactaceae) se han enfocado en las especies ecóndmicamente importantes, por lo que es necesario un mayor conocimiento de la diversidad genética cuando se compara entre las especies silvestres y las especies cultivadas localmente, esto con elfin de ampliar a futuro el uso de las cactáceas. El presente trabajo forma parte de un estudio etnobotánico más amplio llevado a cabo en el Valle de Tehuacán-Cuicatlán, México, y se centra en seis formas tradicionales de clasificar aOpuntia pilifera, cactácea usada como alimento por los indígenas Popolocas de San Juan Atzingo. El método tradicional para distinguir entre dichas formas es parte del conocimiento tradicional de la comunidad Popoloca y está basado en el sabor del fruto, el color, el tamaño y en el número de espinas del fruto y de los cladodios. Las huellas genéticas con 129 AFLPs no están correlacionadas con la clasificación morfológica tradicional. No obstante, los AFLPs distinguieron fácilmente entre los 67 individuos deOpuntia pilifera y los 17 individuos silvestres deOpuntia velutina que conformaron al grupo externo.

The domestic goat as a potential seed disperser of Mimosa luisana (Leguminosae, Mimosoideae) in the Tehuacán-Cuicatlán Valley, Mexico

Mimosa luisana is functionally important in the Tehuacan-Cuicatlan Valley, Mexico, since it is able to create favourable microsites for the establishment of other plant species. The endozoochory of M. luisana seeds by goats was evaluated in terms of excrement deposition pattern, seed survival and germination. The excrement deposition pattern was evaluated by collecting pellets in four plots of 25 × 2 m randomly placed in a grazing area and recording the microhabitat where pellets were found. Seed survival and germination were evaluated by feeding the goats with seeds and collecting dung pellets at 8-h intervals for 80 h. Seeds from goat pellets (treatment) and seeds collected from pods (control) were placed in a germination chamber for 24 d. Goats mainly deposited M. luisana seeds in viable sites (open areas) for growth. Mimosa luisana seeds survived the goat digestive treatment (5.91% ± 2.86%) and most of them (67% ± 25.9%) were recovered 8–32 h after ingestion. Goat gut treatment increased M. luisana final germination (47.5% ingested, 5.83% control) and shortened initial and mean time of germination. Our results indicate that goats may be an efficient disperser of M. luisana seeds.