Najera-Hillman E.,COSTASALVAJE A.C |
Mandujano S.,Institute Ecologia Ac Inecol
Wildlife Biology in Practice | Year: 2013
Stable isotope analyses of tissues and faeces offer an alternative to study the dietary ecology in wild animal populations. Faecal isotope analyses are advantageous because samples are easy to obtain in the field, their isotopic composition is related to the food ingested and allow for documenting short-term diet variability. Therefore, we estimated diet-faeces trophic shifts in white-tailed deer (Odocoileus virginianus) fed on a constant diet. The observed diet-faeces trophic shifts (0.81% for δ13C and 2.13‰ for δ15N) were different to the trophic shifts reported for other herbivores. However, our estimates proved to be useful when applied to a mixing model to quantify the contributions of multiple food sources to the deer's diet. Our diet-faeces trophic shift estimates are reliable measurements that can be used to expand the potential of stable isotope analyses in white-tailed deer dietary ecology studies. © 2013 E. Nájera-Hillman & S. Mandujano.
Alvarez-Molina L.L.,Institute Ecologia Ac Inecol |
Martinez M.L.,Institute Ecologia Ac Inecol |
Lithgow D.,Institute Ecologia Ac Inecol |
Mendoza-Gonzalez G.,Institute Ecologia Ac Inecol |
And 3 more authors.
Journal of Coastal Research | Year: 2013
Palafoxia lindenii A. Gray. Palafoxia lindenii A. Gray is a short shrub endemic to the coastal dunes located in the central region of the Gulf of Mexico, mainly in the state of Veracruz. In this study we assembled information on this species and described the taxonomy and variation of the species, its phylogeny and geographical distribution, plant communities, physiological ecology, population biology, reproduction, geomorphological interactions, biotic interactions, response to water levels, and economic importance. The genus Palafoxia includes 12 species, all of them native to North America. The size of seeds varies widely along the geographic distribution of the species, which is most abundant in hot but not very humid sites. This species produces seeds all year long, although individuals do not reproduce simultaneously. Seeds germinating at the onset of the rainy season have a better survival rate than late cohorts. It is one of the first mobile dune colonizers. Similar to other dune species, it not only tolerates burial by sand, but grows better after burial and because of this it is a good foredune builder and forms trailing-ridges. It has a strong association with mycorrhizal fungi, which enhance growth and survival, but only when the plant is not under stress. Because of its dune-forming ability, the plant is important for the beach and coastal dunes as well as for the protection of coastal infrastructure. The leaves contain flavonoids with important antioxidative effects that benefit human health. Development and tourism along the coast are rapidly reducing the habitat of this species. © 2012, the Coastal Education & Research Foundation.
Mendez-Dewar G.,Institute Ecologia Ac Inecol |
Gonzalez-Espinosa M.,Colegio de Mexico |
Equihua M.,Institute Ecologia Ac Inecol
IForest | Year: 2015
Attributes and frequency of forest gaps are usually described in reference to a one-dimensional gradient of light, which may relate to their disturbance dynamics. Similarly, species are customarily classified by their light response. We propose a bi-dimensional light framework that facilitates the understanding and comparison of forest systems and the understanding of plant responses to the complex light environment. This light plane is based on two spatially related components: (1) light received directly on a particular point (Focal); and (2) a statistical summary of the immediate environment representing the light conditions surrounding that point (Context). The contrast between these two values is null when Focal=Context and positive when Focal>Context or otherwise negative. Light was assessed using hemispherical photographs using a spatial arrangement of pictures spaced ~3 m in-between. Eight forest plots were surveyed, each with a central gap of different size. Sapling performance of Alnus acuminata, Cornus excelsa, Liquidambar styraciflua, Persea americana and Quercus laurina was also assessed within these plots. Measurements of stem height, basal diameter, and slenderness allometry were taken over a period of more than two years. We found in the light plane that plots were dis - tributed in a pattern congruent with their estimated degree of disturbance (gap size), which spanned wide areas in the plane. Liquidambar styraciflua. and Quercus laurina were found to be sensitive to focal light, irrespective of context light. All species responded to focal light under negative contrast. Cornus and Persea grew taller and more slender as focal light increased, particularly under null contrast. There is evidence suggesting that plant growth is dependent on the contrast measured. Thus, it would be relevant to devise a functional classification of tree species that considers their response to both direct light and luminosity of the immediate environment as measured by a contrast value. © SISEF.
Sangabriel-Conde W.,Institute Ecologia Ac Inecol |
Negrete-Yankelevich S.,Institute Ecologia Ac Inecol |
Maldonado-Mendoza I.E.,National Polytechnic Institute of Mexico |
Trejo-Aguilar D.,University of Veracruz
Biology and Fertility of Soils | Year: 2014
Different degrees of dependency on the activity of arbuscular mycorrhizal fungi (AMF) exist between native maize landraces and hybrids. In Los Tuxtlas, Mexico, the Popoluca people maintain a traditional polycultural land management with more than 15 native landraces of maize; however, it is not known whether the recent substitution of local maize for improved hybrids and fertilization has affected the integrity of the mycorrhizal symbiosis in these naturally phosphorus-poor systems. A greenhouse experiment was conducted to evaluate the response of four Popoluca maize landraces and the hybrid Texcoco to the presence of native AMF in conditions of low and medium P input (5 and 65 mg kg−1, respectively). After 120 days in both P treatments, the native landraces Black and Yellow presented higher colonization and had acquired more P in their shoot biomass than the hybrid. The moderate fertilization did not appear to have affected the integrity of the mycorrhizal symbiosis, since all of the maize types presented a positive mycorrhizal dependency (2–14 %). Under low P conditions, the Texcoco hybrid maize presented one of the highest mycorrhizal dependencies; however, unlike the local landraces, this was not reflected in a higher tissue P concentration. The results obtained indicate that the nativemaize Blackwas the best at capturing symbiotic and direct P, which makes this landrace an important genetic and cultural heritage for the Popoluca and for the world. © Springer-Verlag Berlin Heidelberg 2014.
Moo-Llanes D.,Instituto Nacional Of Salud Publica Insp |
Ibarra-Cerdena C.N.,Instituto Nacional Of Salud Publica Insp |
Ibarra-Cerdena C.N.,CINVESTAV |
Rebollar-Tellez E.A.,Autonomous University of Nuevo León |
And 3 more authors.
PLoS Neglected Tropical Diseases | Year: 2013
Ecological niche models are useful tools to infer potential spatial and temporal distributions in vector species and to measure epidemiological risk for infectious diseases such as the Leishmaniases. The ecological niche of 28 North and Central American sand fly species, including those with epidemiological relevance, can be used to analyze the vector's ecology and its association with transmission risk, and plan integrated regional vector surveillance and control programs. In this study, we model the environmental requirements of the principal North and Central American phlebotomine species and analyze three niche characteristics over future climate change scenarios: i) potential change in niche breadth, ii) direction and magnitude of niche centroid shifts, iii) shifts in elevation range. Niche identity between confirmed or incriminated Leishmania vector sand flies in Mexico, and human cases were analyzed. Niche models were constructed using sand fly occurrence datapoints from Canada, USA, Mexico, Guatemala and Belize. Nine non-correlated bioclimatic and four topographic data layers were used as niche components using GARP in OpenModeller. Both B2 and A2 climate change scenarios were used with two general circulation models for each scenario (CSIRO and HadCM3), for 2020, 2050 and 2080. There was an increase in niche breadth to 2080 in both scenarios for all species with the exception of Lutzomyia vexator. The principal direction of niche centroid displacement was to the northwest (64%), while the elevation range decreased greatest for tropical, and least for broad-range species. Lutzomyia cruciata is the only epidemiologically important species with high niche identity with that of Leishmania spp. in Mexico. Continued landscape modification in future climate change will provide an increased opportunity for the geographic expansion of NCA sand flys' ENM and human exposure to vectors of Leishmaniases. © 2013 Moo-Llanes et al.
Rojas P.,Institute Ecologia Ac Inecol |
Fragoso C.,Institute Ecologia Ac Inecol |
Mackay W.P.,University of Texas at El Paso
Sociobiology | Year: 2014
Most of Mexican coastal dunes from the Gulf of Mexico have been severely disturbed by human activities. In the state of Veracruz, the La Mancha Reserve is a very well preserved coastal community of sand dunes, where plant successional gradients are determined by topography. In this study we assessed species richness, diversity and faunal composition of ant assemblages in four plant physiognomies along a gradient of plant succession: grassland, shrub, deciduous forest and subdeciduous forest. Using standardized and non-standardized sampling methods we found a total of 121 ant species distributed in 41 genera and seven subfamilies. Grassland was the poorest site (21 species) and subdeciduous forest the richest (102 species). Seven species, with records in ≥10% of samples, accounted 40.8% of total species occurrences: Solenopsis molesta (21.6%), S. geminata (19.5%), Azteca velox (14%), Brachymyrmex sp. 1LM (11.7%), Dorymyrmex bicolor (11.2%), Camponotus planatus (11%) and Pheidole susannae (10.7%). Faunal composition between sites was highly different. Nearly 40% of all species were found in a single site. In all sites but grassland we found high abundances of several species typical of disturbed ecosystems, indicating high levels of disturbance. A species similarity analysis clustered forests in one group and grassland and shrub in another, both groups separated by more than 60% of dissimilarity. Similarity of ant assemblages suggests that deciduous and subdeciduous forests represent advanced stages of two different and independent successional paths.
Peters R.,TU Dresden |
Vovides A.G.,TU Dresden |
Vovides A.G.,Institute Ecologia Ac Inecol |
Luna S.,TU Dresden |
And 2 more authors.
Ecological Modelling | Year: 2014
Models based on allometric responses to competing neighbours and environmental conditions in mangrove forests are increasingly available. However, the improvement of these models requires a mechanistic understanding of how individual trees allocate biomass. This study introduces a new tree model (BETTINA) focusing on this issue. It is designed to investigate the response of trees in terms of biomass allocation patterns to environmental conditions. Additionally, it is suitable as a component of an individual-based mangrove stand model. BETTINA describes the plasticity of trees in growth patterns depending on their below-ground resource uptake. In contrast to the existing mangrove stand models, BETTINA focusses explicitly on the processes leading to variation in resource availability. Based on the physical principle of osmotic potential of solutions, the direct influence of salinity on plant water availability is considered. Allometric model parameters are not restricted to only the above-ground measures of trees' traits (such as stem diameter and height), but also characterize below-ground biomass. Within BETTINA these measures are not limited to predefined empirical maximum values, but are the result of and depend on environmental conditions.The model is suitable to explain allometric measures and relations in dependence on total plant size and environmental conditions (for now salinity and light), and has a great potential for a physiologically and physically based improvement of plant component related biomass estimations. © 2014 Elsevier B.V.
Goldarazena A.,Institute Ecologia Ac Inecol |
Infante F.,Colegio de Mexico |
Ortiz J.A.,Colegio de Mexico
Florida Entomologist | Year: 2014
Approximately 6000 species of Thysanoptera have been described worldwide. They are particularly diverse in the Neotropics, living in a wide range of environments. Although many species of thrips are well known as inhabitants of cultivated plants, there are others that are abundant in other types of habitats. In the present study we conducted a survey in the "Biosphere Reserve of Volcan Tacana" with the main objective to know the native fauna of thrips. The results confirm the presence of 112 species in 52 genera and 4 families. Our survey indicates that this reserve contains a great biodiversity of Thysanoptera. A full check-list of species is provided.
The international long term ecological research (ilter) network after 20 years since its creation: Advances and challenges [La Red Internacional de Investigación Ecológica a Largo Plazo (ILTER) a 20 años de su creación: Sus avances y retos]
Maass M.,National Autonomous University of Mexico |
Equihua M.,Institute Ecologia Ac Inecol
Bosque | Year: 2014
Twenty years after being established, the ILTER network embraces more than 600 groups from 37 countries. The ecological research at the ILTER network has moved from a merely ecological focus toward a more socio-ecological approach. The network is now more committed to social needs and with higher international presence. An important challenge in the next years will be to encourage a more socioecosystem and trans-disciplinary research. Its wide and flexible research agenda, along with its particular commitment from its groups to work on specific sites for a long time (know as “site based research”), makes ILTER particularly useful and relevant in dealing with the current environmental crisis. The network has incorporated tools and protocols to improve collaboration, such as common metadata management protocols and a multilingual information research system. It is still necessary to improve the efficiency of information delivery to the general public, promoting a more integrated, useful, comprehensive and local context information. The network should also keep promoting “bottom up” initiatives as well as the participation of students and early career scientists. We cannot expect the same level of participation between networks. However, we do expect the same level of commitment and should promote the evaluation of the national networks; not as an exclusion process, but as a mechanism to stimulate collaboration, as well as for an early detection of problems of integration. The ILTER network should keep increasing its geographic presence promoting the integration of single affiliated sites as seeds for the development of future national networks. © 2014, Universidad Austral de Chile. All Rights reserved.
PubMed | University of Alicante and Institute Ecologia Ac Inecol
Type: Journal Article | Journal: PloS one | Year: 2015
The assessment of the relationship between species diversity, species interactions and environmental characteristics is indispensable for understanding network architecture and ecological distribution in complex networks. Saproxylic insect communities inhabiting tree hollow microhabitats within Mediterranean woodlands are highly dependent on woodland configuration and on microhabitat supply they harbor, so can be studied under the network analysis perspective. We assessed the differences in interacting patterns according to woodland site, and analysed the importance of functional species in modelling network architecture. We then evaluated their implications for saproxylic assemblages persistence, through simulations of three possible scenarios of loss of tree hollow microhabitat. Tree hollow-saproxylic insect networks per woodland site presented a significant nested pattern. Those woodlands with higher complexity of tree individuals and tree hollow microhabitats also housed higher species/interactions diversity and complexity of saproxylic networks, and exhibited a higher degree of nestedness, suggesting that a higher woodland complexity positively influences saproxylic diversity and interaction complexity, thus determining higher degree of nestedness. Moreover, the number of insects acting as key interconnectors (nodes falling into the core region, using core/periphery tests) was similar among woodland sites, but the species identity varied on each. Such differences in insect core composition among woodland sites suggest the functional role they depict at woodland scale. Tree hollows acting as core corresponded with large tree hollows near the ground and simultaneously housing various breeding microsites, whereas core insects were species mediating relevant ecological interactions within saproxylic communities, e.g. predation, competitive or facilitation interactions. Differences in network patterns and tree hollow characteristics among woodland sites clearly defined different sensitivity to microhabitat loss, and higher saproxylic diversity and woodland complexity showed positive relation with robustness. These results highlight that woodland complexity goes hand in hand with biotic and ecological complexity of saproxylic networks, and together exhibited positive effects on network robustness.