Current and Future Distribution of the Tropical Tree Cedrela odorata L. in Mexico under Climate Change Scenarios Using MaxLike.

Climate change is recognized as an important threat to global biodiversity because it increases the risk of extinction of many species on the planet. Mexico is a megadiverse country and native tree species such as red cedar (Cedrela odorata) can be used to maintain forests while helping mitigate climate change, because it is considered a fast growing pioneer species with great economic potential in the forestry industry. In order to assess possible shifts in areas suitable for C. odorata plantations in Mexico with ecological niche models, we used the MaxLike algorithm, climate variables, the geo-referenced records of this species, three general circulation models and three scenarios of future emissions. Results show a current potential distribution of 573,079 km2 with an average probability of occurrence of 0.93 (± 0.13). The potential distribution area could increase up to 650,356 km2 by 2060 according to the general circulation model HADCM3 B2, with an average probability of occurrence of 0.86 (± 0.14). Finally, we delimited an area of 35,377 km2 that has a high potential for the establishment of C. odorata plantations, by selecting those sites with optimal conditions for its growth that are outside protected areas and are currently devoid of trees. C. odorata has a significant potential to help in the mitigation of the effects of climate change. Using MaxLike we identified extense areas in Mexico suitable to increase carbon sequestration through plantations of this highly valued native tree species.

Fitness cost implications of PhiC31-mediated site-specific integrations in target-site strains of the Mexican fruit fly, Anastrepha ludens (Diptera: Tephritidae).

Site-specific recombination technologies are powerful new tools for the manipulation of genomic DNA in insects that can improve transgenesis strategies such as targeting transgene insertions, allowing transgene cassette exchange and DNA mobilization for transgene stabilization. However, understanding the fitness cost implications of these manipulations for transgenic strain applications is critical. In this study independent piggyBac-mediated attP target-sites marked with DsRed were created in several genomic positions in the Mexican fruit fly, Anastrepha ludens. Two of these strains, one having an autosomal (attP_F7) and the other a Y-linked (attP_2-M6y) integration, exhibited fitness parameters (dynamic demography and sexual competitiveness) similar to wild type flies. These strains were thus selected for targeted insertion using, for the first time in mexfly, the phiC31-integrase recombination system to insert an additional EGFP-marked transgene to determine its effect on host strain fitness. Fitness tests showed that the integration event in the int_2-M6y recombinant strain had no significant effect, while the int_F7 recombinant strain exhibited significantly lower fitness relative to the original attP_F7 target-site host strain. These results indicate that while targeted transgene integrations can be achieved without an additional fitness cost, at some genomic positions insertion of additional DNA into a previously integrated transgene can have a significant negative effect. Thus, for targeted transgene insertions fitness costs must be evaluated both previous to and subsequent to new site-specific insertions in the target-site strain.

Insecticidal activity of raw ethanolic extracts from Magnolia dealbata Zucc on a tephritid pest.

Ethanolic extracts from Magnolia dealbata (Zucc.) (Magnoliaceae); leaves, bark, seeds, sarcotesta and flowers were evaluated for insecticidal activity against adults of the Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae). Using feeding bioassays composed from sugar-extract mixtures, only the extract from sarcotesta indicated insecticidal activity against the flies. The extracts from the other four plant tissues (leaves, bark, seeds and flowers) did not manifest any biological activity. The most effective extract was obtained from oven-dried sarcotesta, whereas extracts from fresh sarcotesta were inactive. Our results suggest that M. dealbata sarcotesta contains secondary metabolites with insecticidal activity against A. ludens adults. These metabolites are as potent as natural pyrethins and represent a potential substance for controlling this type of pest.

Opportunity for the study of critical successional processes for the restoration and conservation of mountain forest: The case of mexican pine plantations / Oportunidad para el estudio de procesos críticos sucesionales para la restauración y conservación de bosques de montaña: El caso de las plantaciones de pino en México / Oportunidade para o estudo de processos críticos sucesionais para a restauração e conservação de bosques de montanha: O caso das plantaçãos de pinheiros no México

It has become clear that native species are incorporated naturally under the canopy of many tree plantations. This process of incorporation (facilitation) can be used as an opportunity to create successional models in restoration and species reintroduction projects. The need to incorporate basic ecological information is a critical issue in the process of ecosystem restoration. Pinus is a genus widely used in plantations worldwide. In Mexico, 199 790.4ha are planted with pine each year. Many of these plantations have been established with rehabilitation and conservation goals, and provide an opportunity for restoration through the reintroduction of native species of plants and animals. Because pine species are considered as pioneers in forest successional stages, pine plantations represent natural laboratories that can be used to test scientific hypothesis to strengthen the restoration and reintroduction programs. These plantations also represent an opportunity to apply scientific knowledge in practical field conservation and address the science-policy interface. In this essay, we presented arguments focused on the importance of plantations as areas for experimentation, given the diversity of environments in which they are found, from sea level to high altitudes, as well as the diversity in their structure and composition.

Se ha evidenciado que bajo el dosel de muchas plantaciones forestales se incorporan, de manera natural, especies nativas. Este proceso de incorporación (facilitación), puede ser usado como una oportunidad para crear modelos sucesionales en proyectos de restauración y reintroducción de especies. La necesidad de incorporar información ecológica básica es una cuestión crítica en el proceso de restauración de ecosistemas. Pinus es un género ampliamente usado en plantaciones a nivel mundial. En México, las plantaciones de pino representan 199 790,4ha al año. Muchas de éstas se han establecido con objetivos de rehabilitación y conservación, y constituyen una oportunidad para la restauración a partir de la reintroducción de especies de plantas y animales nativos. Debido a que los pinos son considerados como especies pioneras de la sucesión, las plantaciones de pino representan laboratorios naturales que nos permiten invalidar hipótesis científicas para fortalecer programas de restauración o reintroducción de especies. Estas plantaciones también representan una oportunidad para aplicar el conocimiento científico en la práctica de la conservación de campo y atender la interfase política-sociedad. En el presente ensayo presentamos argumentos enfocados hacia la importancia que las plantaciones tienen como áreas de experimentación dada la diversidad de ambientes en las que se encuentran, desde el nivel del mar hasta las grandes altitudes, así como de estructura y composición de las mismas.

Tem-se evidenciado que sob o dossel de muitas plantações florestais se incorporam, de maneira natural, espécies nativas. Este processo de incorporação (facilitação), pode ser usado como uma oportunidade para criar modelos sucessionais em projetos de restauração e reintrodução de espécies. A necessidade de incorporar informação ecológica básica é uma questão crítica no processo de restauração de ecossistemas. Pinus é um gênero amplamente usado em plantações a nível mundial. No México, as plantações de pinheiros representam 199.790,4 ha ao ano. Muitas destas foram estabelecidas com objetivos de reabilitação e conservação, e constituem uma oportunidade para a restauração apartir da reintrodução de espécies de plantas e animais nativos. Devido a que os pinheiros são considerados como espécies pioneiras da sucessão, as plantações de pinheiros representam laboratórios naturais que nos permitem invalidar hipóteses científicas para fortalecer programas de restauração ou reintrodução de espécies. Estas plantações também representam uma oportunidade para aplicar o conhecimento científico na prática da conservação de campo e atender a interfase política-sociedade. No presente ensaio apresentamos argumentos focados para a importância que as plantações têm como áreas de experimentação devido à diversidade de ambientes em que se encontram, do nível do mar até as grandes altitudes, assim como de estrutura e composição das mesmas.

Species diversity, structure and dynamics of two populations of an endangered species, Magnolia dealbata (Magnoliaceae).

Little is known about the ecology and demography of the genus Magnolia. Magnolia dealbata Zucc. is an endangered species endemic to Mexico. Two contrasting populations of M. dealbata (one from the grasslands and other from a secondary cloud forest) were studied. We asked the following questions: (a) Are size structure (diameter at breast height, DBH) and infrutescence production significantly different between the two populations? (b) What are the populations' growth rates (lambda) based on an initial 1987 study? (c) Are the associated species diversity indices of these M. dealbata populations significantly different? The results show no significant differences between the population size structure (p=.094); the growth rates of the populations were 0.992 in grassland and 1.053 in secondary cloud forest. The number of infrutescences produced in year 2001 and DBH relationship were significantly linear (p<.001) in both populations, and there was no significant difference (p>.01) between their slopes. The diversity indices were not significantly different (p>.05), and only 54% of the species were common to both sites. Our study suggests that both populations are relatively stable and that the management history could impact more on the species composition than on the diversity indices.