Summary 1.Coffee is produced in tropical regions of the world, largely in Latin America. Coffee cultivation techniques range from traditional systems, where coffee grows under a diverse canopy of shade trees (shade-coffee plantations), to modern systems, where coffee grows without any type of shade (sun-coffee plantations). Shade-coffee plantations provide refuge for forest fauna in otherwise deforested landscapes. The conservation value of these agro-ecosystems depends upon their structural and floristic diversity. 2. The way coffee producers manage the vegetation, including the epiphytic component, may profoundly affect the value of plantations for conserving biological diversity. Shadecoffee certification programmes have emerged to verify that coffee advertised as 'shade grown' is actually grown on highly biodiverse plantations. Although these programmes universally encourage epiphyte protection from pruning (a common practice), there has been no experimental evaluation of the importance of epiphytes in supporting faunal diversity. We report the effect of experimentally removing epiphytes on the bird assemblage in a shade-coffee farm near Coatepec, Veracruz, Mexico. 3. We established two matching pairs of epiphyte removal and control plots. We compared bird diversity and abundance, based on daily censuses during the breeding and non-breeding season. We used existing information on the way in which birds use epiphytes as foraging and nesting substrates to explain the presence of different species in plots with epiphytes. 4. Plots without epiphytes tended to be less diverse than plots with epiphytes, but rarefaction analysis and  showed no significant differences in species richness between treatments in any of the seasons. Mean bird abundance was significantly higher in plots with epiphytes during both seasons, and a multidimensional scaling analysis showed that bird community structure differed between the two treatments. 5. Eighteen forest bird species were significantly more abundant in plots with epiphytes. Three non-forest species were more common in plots without epiphytes. Resident bird species that used epiphytes as a nesting substrate were significantly more abundant in plots with epiphytes. 6. When epiphytes are removed, canopy cover, foraging substrates, nest sites and nest materials are eliminated and microclimatic conditions change. This could increase predation on adult birds and nests, increase intra-and interspecific competition, and decrease individual survivorship. 7. Synthesis and applications. This is the first experimental assessment of the importance of epiphytes for birds. Shade-coffee plantations with epiphytes maintain higher abundance and diversity of the inhabitant bird fauna than plantations without epiphytes. This study reinforces the value of positive epiphyte management as an important factor in shade-grown coffee certification, where the goal is to promote biodiversity conservation.

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In central Veracruz, Mexico, coffee plantations have replaced large areas of lower montane cloud forest. Shade-coffee plantations with high levels of structural diversity provide refuge for forest-dependent biota (e.g., birds and insects). Orchids typical of natural forest may also be found in the canopy of shade-coffee agroecosystems. It is not known, however, whether these are relicts from the original forest vegetation or if the plantations themselves provide the necessary conditions to support a self-sustained orchid population. We studied the population structure of the epiphytic orchids Jacquiniella teretifolia (Sw.) Britton & Willson, Scaphyglottis livida (Lindl.) Schltr., and Maxillaria densa Lindl. in a shade-coffee plantation (commercial polyculture) in central Veracruz. We also studied the previously undescribed reproductive biology of the latter two species. Our results show that the three orchid species had high population densities (>800 plants/ha). In our study site, 50% to 68% of the orchid plants of the target species were young individuals (less than five shoots). Reproductive structures were present in 80% of individuals larger than 30 shoots in the three species. M. densa is self-incompatible, and the fruit set obtained from cross pollination (42.7%) was higher than that obtained from natural pollination (18.2%), suggesting that this species could be pollinator limited. S. livida is autocompatible, not autogamous, and was not pollinator limited. Our results show that the coffee plantation had abundant orchid populations with log-normal size/age structures. Two of the target species, M. densa and S. livida, depend on pollinators to reproduce. It is clear that pollinators that allow orchids to set a high proportion of fruits persist in shade-coffee plantations. Coffee plantations may not replace the original conditions of a forest, but it is possible that these and other orchid species survive and reproduce in coffee plantations that provide appropriate microclimate conditions for the plants, including pollinators. Resumen:En el centro de Veracruz, México, las plantaciones de café han reemplazado a extensasáreas de bosque nublado montano. Las plantaciones cafetaleras de sombra con altos niveles de diversidad estructural proporcionan refugio a biota dependiente de bosques (e. g., aves e insectos). En el dosel de agroecosistemas de café de sombra también se pueden encontrar orquídeas típicas de bosques naturales. Sin embargo, no se conoce si son relictos de la vegetación del bosque original o si las plantaciones mismas proporcionan los recursos necesarios para soportar a una población de orquídeas auto sostenida. Estudiamos la estructura de la población de orquídeas epifitas Jacquiniella teretifolia (Sw.) Britton & Willson, Scaphyglottis livida (Lindl.) Schltr y Maxillaria densa Lindl en una plantación de café de sombra (policultivo comercial) en el centro de Veracruz. También estudiamos la biología reproductiva, no descrita previamente, de lasúltimas dos especies. Nuestros resultados muestran que...

Abstract:The abundance of epiphytes has been assumed to be important in explaining the high diversity of tropical canopy arthropods. In this study we assessed the possible role that the presence of epiphytes may have on the diversity and abundance of canopy insects in an experimental study conducted in a coffee plantation in Coatepec, Veracruz, Mexico. Epiphytes were removed from trees in one of two plots in two sites of the coffee plantation. In each plot we collected insects from three Inga jinicuil trees by knockdown insecticide fogging. Insects were sorted to morphospecies, counted and measured. Trees with epiphytes had significantly higher numbers of species and individuals and insects larger than 5 mm were also more species-rich and abundant in trees with epiphytes. The magnitude of the enhancement was surprisingly large with the epiphyte plot samples having on average 90% more individuals and 22% more species than plots without epiphytes. These differences were even greater for large (>5 mm) insects (184% and 113% respectively). Our results support the tenet that epiphytes provide valuable resources to arthropods, which we have illustrated for canopy insects in shade trees of coffee plantations.

Dioon angustifolium presents high levels of genetic diversity compared with other cycad species, in spite of small population sizes. The recent bottleneck effect did not effectively reduce the genetic variation to the extent of eliminating these populations. The distribution of D. angustifolium appears to be the result of historical biogeographical effects related to the Pleistocene glaciations. It is recommended that this species be catalogued in the IUCN Red List of Threatened Species and conservation efforts be made to preserve it.

The F-statistic values (>0) and the level of gene flow found suggest that habitat fragmentation has broken up the former population structure. In this context, it is proposed that the host trees of T. achyrostachys should be considered as a conservation priority, since they represent the limiting factor to bromeliad population growth and connectivity.

Unique components of tropical habitats, such as abundant vascular epiphytes, influence the distribution of species and can contribute to the high diversity of many animal groups in the tropics. However, the role of such features in habitat selection and demography of individual species has not been established. Understanding the mechanisms of habitat selection requires both experimental manipulation of habitat structure and detailed estimation of the behavioral and demographic response of animals, e.g., changes in movement patterns and survival probabilities. Such studies have not been conducted in natural tropical forest, perhaps because of high habitat heterogeneity, high species diversity, and low abundances of potential target species. Agroforestry systems support a less diverse flora, with greater spatial homogeneity which, in turn, harbors lower overall species diversity with greater numerical dominance of common species, than natural forests. Furthermore, agroforestry systems are already extensively managed and lend themselves easily to larger scale habitat manipulations than protected natural forest. Thus, agroforestry systems provide a good model environment for beginning to understand processes underlying habitat selection in tropical forest animals. Here, we use multistate, capture-recapture models to investigate how the experimental removal of epiphytes affected monthly movement and survival probabilities of two resident bird species (Common Bush-Tanager [Chlorospingus ophthalmicus] and Golden-crowned Warbler [Basileuterus culicivorus]) in a Mexican shade coffee plantation. We established two paired plots of epiphyte removal and control. We found that Bush-Tanagers were at least five times more likely to emigrate from plots where epiphytes were removed compared to control plots. Habitat-specific movement patterns were not detected in the warbler. However, unlike the Golden-crowned Warbler, Common Bush-Tanagers depend upon epiphytes for nest sites and (seasonally) for foraging. These dispersal patterns imply that active habitat selection based on the presence or absence of epiphytes occurs in C. ophthalmicus on our study area. Survival rates did not vary with habitat in either species. Interestingly, in both species, survival was higher in the nonbreeding season, when birds were in mixed-species flocks. Movement by Common Bush-Tanagers into areas with epiphytes occurred mostly during the breeding season, when mortality-driven opportunity was greatest.

Mexico as a megadiverse country houses between 6 and 8% of the world's flora. However, the Mexican flora is facing challenges, including the presence of at least 981 threatened plant species and 618 exotic plant species, habitat loss, pollution, overexploitation of natural resources and the adverse effects of climate change, which are compromising its conservation and sustainable use. Mexico has been actively involved in the development and update of the Global Strategy for Plant Conservation (GSPC) adopted by the Convention on Biological Diversity (CBD). As a party to CBD, Mexico has established a Coordinating Committee for the Mexican Strategy for Plant Conservation (MSPC), which has adapted the GSPC to fit national needs and drafted a number of projects, indicators, means of verification and actors to ensure that the MSPC, as a public policy tool, really drives conservation and sustainable use actions among all sectors and lasts beyond the current administration. An agenda is being developed with activities that include the following: approaching Congress, identifying the relevance of the MSPC in the National Development Plan and the Mexican Biodiversity Strategy, making use of current environmental policies and an aggressive awareness programme. The MSPC includes simultaneous programmes of technical and political work. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 166, 326–330.