REGIONES PRIORITARIAS PARA LA CONSERVACIÓN DEL BOSQUE MESÓFILO DE MONTAÑA

Cloud forests (CFs) shelter an extraordinary biodiversity, play a key role in the regulation of water and nutrient cycles, and are the most threatened terrestrial ecosystems in México. Although all CFs are important, it is necessary to identify the areas where the actions directed at their sustainable management, conservation and restoration are more urgent. An initiative by the National Commission for the Knowledge and Use of Biodiversity is presented, to develop a diagnosis of the CFs in México in terms of their quality, main threats to their permanence and quality, as well as the opportunities present for their maintenance, recovery and social characteristics of their owners and users. Fifteen sub regions of critical priority were identified, 17 of high, nine of medium and four were pending due to the lack of information. The main recommendations to contribute to the conservation of this very valuable ecosystem are presented.Los bosques de niebla o bosques mesófilo de montaña (BMM) resguardan una biodiversidad extraordinaria, juegan un papel clave en la regulación de los ciclos hidrológicos y son los ecosistemas terrestres más amenazados en México. Si bien todos los BMM son importantes, es necesario identificar aquellas áreas donde las acciones encaminadas a su manejo sustentable, conservación y restauración son de carácter más urgente. Se presenta una iniciativa de la Comisión Nacional para el Conocimiento y Uso de la Biodiversidad para desarrollar un diagnóstico del BMM en México en términos de su calidad, las principales amenazas a su permanencia y a su calidad, así como las oportunidades existentes para su mantenimiento, recuperación y características sociales de sus propietarios y usuarios. Se identificaron 15 subregiones de prioridad crítica, 17 de alta, nueve de media y cuatro quedaron pendientes debido a la falta de información. Se presentan las principales recomendaciones para contribuir a la conservación de este ecosistema tan valioso

Wolbachia pipientis associated with tephritid fruit fly pests: from basic research to applications

Members of the true fruit flies (family Tephritidae) are among the most serious agricultural pests worldwide, whose control and management demands large and costly international efforts. The need for cost-effective and environmentally friendly integrated pest management (IPM) has led to the development and implementation of autocidal control strategies. These approaches include the widely used sterile insect technique and the incompatible insect technique (IIT). IIT relies on maternally transmitted bacteria (namely Wolbachia) to cause a conditional sterility in crosses between released mass-reared Wolbachia-infected males and wild females, which are either uninfected or infected with a different Wolbachia strain (i.e., cytoplasmic incompatibility; CI). Herein, we review the current state of knowledge on Wolbachia-tephritid interactions including infection prevalence in wild populations, phenotypic consequences, and their impact on life history traits. Numerous pest tephritid species are reported to harbor Wolbachia infections, with a subset exhibiting high prevalence. The phenotypic effects of Wolbachia have been assessed in very few tephritid species, due in part to the difficulty of manipulating Wolbachia infection (removal or transinfection). Based on recent methodological advances (high-throughput DNA sequencing) and breakthroughs concerning the mechanistic basis of CI, we suggest research avenues that could accelerate generation of necessary knowledge for the potential use of Wolbachia-based IIT in area-wide integrated pest management (AW-IPM) strategies for the population control of tephritid pests.Instituto de GenéticaFil: Mateos, Mariana. Texas A&M University. Departments of Ecology and Conservation Biology, and Wildlife and Fisheries Sciences; Estados UnidosFil: Martinez Montoya, Humberto. Universidad Autónoma de Tamaulipas. Unidad Académica Multidisciplinaria Reynosa Aztlan. Laboratorio de Genética y Genómica Comparativa; MéxicoFil: Lanzavecchia, Silvia Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Conte, Claudia Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Guillén, Karina. El Colegio de la Frontera Sur; MéxicoFil: Morán-Aceves, Brenda M. El Colegio de la Frontera Sur; MéxicoFil: Toledo, Jorge. El Colegio de la Frontera Sur; MéxicoFil: Liedo, Pablo. El Colegio de la Frontera Sur; MéxicoFil: Asimakis, Elias D. University of Patras. Department of Environmental Engineering; GreciaFil: Doudoumis, Vangelis. University of Patras. Department of Environmental Engineering; GreciaFil: Kyritsis, Georgios A. University of Thessaly. Department of Agriculture Crop Production and Rural Environment. Laboratory of Entomology and Agricultural Zoology; GreciaFil: Papadopoulos, Nikos T. University of Thessaly. Department of Agriculture Crop Production and Rural Environment. Laboratory of Entomology and Agricultural Zoology; GreciaFil: Augustinos, Antonios A. Hellenic Agricultural Organization. Institute of Industrial and Forage Crops. Department of Plant Protection; GreciaFil: Segura, Diego Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tsiamis, George. University of Patras. Department of Environmental Engineering; Greci

Above- and below-ground competition between the liana Acacia kameruensis and tree seedlings in contrasting light environments

Proliferation of lianas in canopy gaps can restrict tree regeneration in tropical forests through competition. Liana effects may differ between tree species, depending on tree requirements for above- and below-ground resources. We conducted an experiment in a shade house over 12 months to test the effect of light (7 and 27% external irradiance) on the competitive interactions between seedlings of one liana species and three tree species and the contribution of both above- and below-ground competition. Seedlings of the liana Acacia kamerunensis were grown with tree seedlings differing in shade tolerance: Nauclea diderrichii (Pioneer), Khaya anthotheca (Non-Pioneer Light Demander) and Garcinia afzelii (Non-Pioneer Shade Bearer). Trees were grown in four competition treatments with the liana: no competition, root competition, shoot competition and root and shoot competition. Both root and root–shoot competition significantly reduced relative growth rates in all three tree species. After one year, root–shoot competition reduced growth in biomass to 58% of those (all species) grown in no competition. The root competition treatment had amore important contribution in the effect of the liana on tree growth. Tree seedlings did not respond to competition with the liana by altering their patterns of biomass allocation. Although irradiance had a great effect on tree growth and allocation of biomass, the interaction between competition treatments and irradiance was not significant. Nauclea diderrichii, the tree species which responded most to the effects of competition, showed signs of being pot-bound, the stress of which may have augmented the competition effects. The understanding of the interaction of above- and below-ground competition between lianas and trees and its moderation by the light environment is important for a proper appreciation of the influence of lianas on tropical forest regeneration

Effect of three species of climber on the performance of Ceiba pentandra seedlings in gaps in a tropical forest in Ghana

The proliferation of climbers can have deleterious effects on tree regeneration, especially in forest canopy gaps where climbers increase in abundance. In response to the colonization by climbers, the supporting tree can suffer a reduction in growth and its allometric relationships may be modified. We evaluated the effects of three species of climber on the performance of the pioneer tree Ceiba pentandra in a moist semi-deciduous tropical forest in Ghana. In each of three gaps, four plots were set up, each with eight Ceiba seedlings paired with a single plant of one of three climber species, planted within 5–10 cm of the tree seedling, plus a control (no climber). The climber species were: Centrosema pubescens, a nitrogen-fixing woody climber; Combretum racemosum, a woody climber and Dioscorea praehensilis, an herbaceous climber. After 12 mo, Centrosema and Combretum had about four to five times more biomass than Ceiba seedlings. There was no effect of climber competition on Ceiba biomass growth, and no relationship between climber biomass and Ceiba growth rate. Individual climber species, however, had other effects: Combretum caused a significant reduction in the height and diameter growth of Ceiba, whilst competition with Centrosema was associated with significant reduction in the crown area and increase in internode length in Ceiba. The results indicate that even very different climber species appear to cause negative effects on trees during regeneration

Biomass allocation and photosynthetic responses of lianas and pioneer tree seedlings to light

Lianas are frequently considered as light demanding plants due to their proliferation in gaps and forest edges. Since lianas are exposed to a very heterogeneous light environment, they could be expected to express morphological and physiological plasticity in response to changes in the light environment, as high as that found in pioneer trees. We compared the biomass allocation and photosynthetic responses of seedlings of three species of lianas and two species of pioneer trees to increased light availability. Seedlings were transferred from medium (4‚Äì5 mol m‚à í2 d‚à í1) to high irradiance (12‚Äì15 mol m‚à í2 d‚à í1) in a controlled environment. In general the three liana species allocated fewer resources to the stem in comparison with the trees. The difference in the response between irradiance regimes was similar among the species, with no strong differences between trees and lianas probably due the early stage of the plants. With increase in irradiance plants accumulated more biomass, allocated more resources to the roots and less to the leaves, reduced the leaf area ratio (LAR) and specific leaf area (SLA). The photosynthetic rates recorded were not related to the rates of growth as measured by the increase in dry biomass (RGRm). Regardless of the life form, plants under higher irradiance increased their light compensation point (Lcp) and attained light saturation (Lsp) at higher levels of irradiance, while the saturated photosynthetic rate (Amax) did not show a clear pattern, and dark respiration (Rd) and quantum yield (Q) were not affected by the transference. The understanding of liana and tree seedlings responses to the light environment may have important implications in the dynamics of tropical forest regeneration

Effect of lianas on tree regeneration in gaps and forest understorey in a tropical forest in Ghana

Questions: Do lianas alter the relative success of tree species during regeneration? Are the effects of lianas on tree seedlings moderated by canopy openness? How are patterns of biomass allocation in tree seedlings affected by liana competition? Location: Tropical moist semi-deciduous forest in Ghana. Methods: Seedlings of the trees Nauclea diderrichii (pioneer), Khaya anthotheca (non-pioneer light demander) and Garcinia kola (non-pioneer shade bearer) were planted with the lianas Acacia kamerunensis (fast growing) and Loeseneriella rowlandii (slow growing) in large and small gaps (ca. 15% and 8% PAR respectively) and in the forest understorey (ca. 4% PAR). Seed- ling survival, growth and biomass allocation were measured. Results: Canopy openness moderated the interaction between liana and tree seedlings. The nature of the interaction was both liana and tree species specific and displayed temporal variation. Acacia competition effects were stronger in sites with greater canopy openness. In big gaps, Acacia reduced significantly the biomass of Nauclea by 32% and Khaya by about 50%. Khaya growth in leaf area was five times greater without Acacia, while Nauclea and Garcinia were not affected. Acacia was more plastic than Loeseneriella in response to the environment and the tree species. Our results show that while Loeseneriella, with lower rates of growth, did not affect seedling growth of the three species evaluated, Acacia could alter the relative success of tree species during regeneration. Conclusions: There is evidence that competitive effects by Acacia on tree regeneration through competition could modify tree species capacity to establish. Effects by lianas at the regeneration phase may have important implications for forest management