Books by Cesar Tejeda-Cruz
La presente obra ofrece los resultados científicos sobre el estudio y funcionamiento de las finca... more La presente obra ofrece los resultados científicos sobre el estudio y funcionamiento de las fincas cafetaleras de Veracruz, a través del análisis simultáneo de cambios en la diversidad biológica de 13 grupos taxonómicos distintos, lo que permite hacer comparaciones entre ellos.
Papers by Cesar Tejeda-Cruz
Este libro recopila una amplia gama de estudios valiosos sobre la situación actual de los bosques... more Este libro recopila una amplia gama de estudios valiosos sobre la situación actual de los bosques mesófilos en Chiapas. Incluye trabajos de amplia visión sobre la dinámica de cambio de las existencias de este tipo de vegetación en el transcurso de las últimas tres décadas, hasta estudios puntuales sobre grupos de organismos en particular. De entre ellos, destaca el capítulo sobre el fabuloso y "resplandeciente quetzal”.
Southern Mexico is well known for its high biodiversity. This biodiversity is a result of several... more Southern Mexico is well known for its high biodiversity. This biodiversity is a result of several factors like its geographic position, geographic diversity, and physiographic richness. In particular, Chiapas, Mexico's southernmost state holds seven physiographic zones, including valleys, mountain chains, plateaus, and coastal plains. Most of this biological richness is to be found in the eastern moist forest, northern mountains, central plateau, and Sierra Madre. The Sierra Madre mountain chain harbors some of the very last patches of Cloud Forest, which is one of the most endangered ecosystems both in Mexico and at a global scale. Fortunately, three existing biosphere reserves namely El Triunfo, La Sepultura and Volcán Tacaná, aim to protect and maintain this highly threatened ecosystem. As elsewhere, natural areas compete for land with human activities such as agriculture and cattle ranching, recently, climate change has added up to the list of threats. Only at El Triunfo reserve between 1983 and 1993 were lost 8,946 ha, including 5,084 ha of Cloud Forest. Our research objective, was thus, to evaluate and analyze the natural successional process in a cloud forest along a successional gradient (20-25 years old, 30-35 years old, and mature forest), and to determine the floristic composition, vegetation structure, and species replacement along this gradient.
We compared our results with several other studies on successional gradients elsewhere in the neotropics. Some Costa Rica mature forest has twice the number of species than El Triunfo. However, secondary forest in Costa Rica showed similar numbers to what we found in El Triunfo. These results suggest that secondary forest at El Triunfo could be more diverse than primary forest. The patterns on species diversity and species replacement along a successional gradient we obtained from this study would be of great help to design sound strategies for Cloud Forest restoration. This is very important since little is known on Cloud Forest dynamics and because this habitat is considered one of the most endangered all over the world.
It has been documented that certain types of shade coffee plantations have both biodiversity leve... more It has been documented that certain types of shade coffee plantations have both biodiversity levels similar to natural forest and high concentrations of wintering migratory bird species. These findings have triggered a campaign to promote shade coffee as a means of protecting Neotropical migratory birds. Bird censuses conducted in the El Triunfo Biosphere reserve in southern Mexico have confirmed that shade coffee plantations may have bird diversity levels similar to, or higher than, natural forest. However, coffee and forest differed in species composition. Species with a high sensitivity to disturbance were significantly more diverse and abundant in primary ecosystems. Neotropical migratory birds, granivorous and omnivorous species were more abundant in disturbed habitats. Insectivorous bird species were less abundant only in shaded monoculture. Foraging generalists and species that prefer the upper foraging stratum were more abundant in disturbed habitats, while a decline in low and middle strata foragers was found there. Findings suggests that shade coffee may be beneficial for generalist species (including several migratory species), but poor for forest specialists. Although shade coffee plantations may play an important role in maintaining local biodiversity, and as buffer areas for forest patches, promotion of shade coffee may lead to the transformation of forest into shade coffee, with the consequent loss of forest species.
Over the past decade, various strategies have emerged to address critical habitat losses through ... more Over the past decade, various strategies have emerged to address critical habitat losses through agricultural expansion. The promotion of shade-grown, premium-priced coffee has been highlighted as one alternative. Our research, based on interviews with farmers in Chiapas, disputes some of the assumptions made by shade coffee campaigners. Results revealed a predisposition to converting forest to shade coffee production due to the socioeconomic challenges farmers face and the potential for increasing incomes. To ensure that their well-being is improved at the same time as reducing environmental impacts, there is clearly a need to provide more detailed information on who is responsible for enforcing certification criteria and how this should take place
Studies have documented biodiversity losses due to intensification of coffee management (reductio... more Studies have documented biodiversity losses due to intensification of coffee management (reduction in canopy richness and complexity). Nevertheless, questions remain regarding relative sensitivity of different taxa, habitat specialists, and functional groups, and whether implications for biodiversity conservation vary across regions.We quantitatively reviewed data fromant, bird, and tree biodiversity studies in coffee agroecosystems to address the following questions: Does species richness decline with intensification or with individual vegetation characteristics? Are there significant losses of species richness in coffee-management systems compared with forests? Is species loss greater for forest species or for particular functional groups? and Are ants or birds more strongly affected by intensification? Across studies, ant and bird richness declined with management intensification and with changes in vegetation. Species richness of all ants and birds and of forest ant and bird species was lower in most coffee agroecosystems than in forests, but rustic coffee (grown under native forest canopies) had equal or greater ant and bird richness than nearby forests. Sun coffee (grown without canopy trees) sustained the highest species losses, and species loss of forest ant, bird, and tree species increased with management intensity. Losses of ant and bird species were similar, although losses of forest ants were more drastic in rustic coffee. Richness of migratory birds and of birds that forage across vegetation strata was less affected by intensification than richness of resident, canopy, and understory bird species. Rustic farms protected more species than other coffee systems, and loss of species depended greatly on habitat specialization and functional traits. We recommend that forest be protected, rustic coffee be promoted, and intensive coffee farms be restored by augmenting native tree density and richness and allowing growth of epiphytes.We also recommend that future research focus on potential trade-offs between biodiversity conservation and farmer livelihoods stemming from coffee production.
It has been documented that certain types of shade coffee plantations have both biodiversity leve... more It has been documented that certain types of shade coffee plantations have both biodiversity levels similar to natural forest and high concentrations of wintering migratory bird species. These findings have triggered a campaign to promote shade coffee as a means of protecting Neotropical migratory birds. Bird censuses conducted in the El Triunfo Biosphere reserve in southernMexico have confirmed that shade coffee plantations may have bird diversity levels similar to, or higher than, natural forest. However, coffee and forest differed in species composition. Species with a high sensitivity to disturbance were significantly more diverse and abundant in primary ecosystems. Neotropical migratory birds, granivorous and omnivorous species were more abundant in disturbed habitats. Insectivorous bird species were less abundant only in shaded monoculture. Foraging generalists and species that prefer the upper foraging stratum were more abundant in disturbed habitats, while a decline in low and middle strata foragers was found there. Findings suggests that shade coffee may be beneficial for generalist species (including several migratory species), but poor for forest specialists. Although shade coffee plantations may play an important role in maintaining local biodiversity, and as buffer areas for forest patches, promotion of shade coffee may lead to the transformation of forest into shade coffee, with the consequent loss of forest species.
In 1998, storms related to Hurricane Isis caused extensive gaps in the cloud forest of El Triunfo... more In 1998, storms related to Hurricane Isis caused extensive gaps in the cloud forest of El Triunfo Biosphere Reserve in Chiapas, Mexico, where severe storms are infrequent. We examined how this disturbance affected bird species composition. Species richness and composition were similar both between pre- and post-disturbance forest and between newly created gaps and plots that remained forested after the hurricane. However, differences in response guilds were greater between pre- and post-disturbance plots than between forest plots with gaps after disturbance. Granivorous, omnivorous, and terrestrial species were more abundant before the hurricane, whereas insectivorous, midstory, and generalist foragers were more abundant after the hurricane. In addition, species with high sensitivity to disturbance were more abundant in the pre-disturbance forest, while low sensitivity species were more abundant after disturbance. In the post-disturbance forest, insectivorous species were most abundant in gaps and terrestrial-canopy foragers were most abundant in forest plots. Permanently open areas had significantly lower species richness, but had lowland generalist and second-growth species not present in the cloud forest. Results suggest that changes in species composition were not limited to the newly created gaps, but also affected the whole forest. The decline of high sensitivity species after disturbance supports the hypothesis that disturbance negatively affects specialists and benefits generalist species. Although there is evidence that natural communities tend to return to pre-disturbance conditions, changes in community structure could be aggravated if recurrent hurricanes occur before succession takes place.
Municipal-level inventories of the avifauna and its application to conservation: the case of Zaca... more Municipal-level inventories of the avifauna and its application to conservation: the case of Zacapoaxtla, Puebla, Mexico. – Bird Inventories at the municipal-level could improve the selection of priority areas in conservation. Based on an update of the avifauna of Zacapoaxtla Municipality, Puebla, Mexico, we used vegetation type and land use within the municipality to analyze bird species’ richness, endemism, and species at risk. We also examined the general distribution patterns and described birds’ seasonality. The highest species richness, and the highest numbers of endemic, threatened, and exclusive species were found in cloud forest; followed, in descending order, by pine forest, pine-oak forest, temporary agriculture and cultivated grasslands. Based on this information, we propose priority areas for bird preservation within the municipality and we discussed the role of inventories at this scale as a strategy for conservation.
Short notes by Cesar Tejeda-Cruz
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Books by Cesar Tejeda-Cruz
Papers by Cesar Tejeda-Cruz
We compared our results with several other studies on successional gradients elsewhere in the neotropics. Some Costa Rica mature forest has twice the number of species than El Triunfo. However, secondary forest in Costa Rica showed similar numbers to what we found in El Triunfo. These results suggest that secondary forest at El Triunfo could be more diverse than primary forest. The patterns on species diversity and species replacement along a successional gradient we obtained from this study would be of great help to design sound strategies for Cloud Forest restoration. This is very important since little is known on Cloud Forest dynamics and because this habitat is considered one of the most endangered all over the world.
Short notes by Cesar Tejeda-Cruz
We compared our results with several other studies on successional gradients elsewhere in the neotropics. Some Costa Rica mature forest has twice the number of species than El Triunfo. However, secondary forest in Costa Rica showed similar numbers to what we found in El Triunfo. These results suggest that secondary forest at El Triunfo could be more diverse than primary forest. The patterns on species diversity and species replacement along a successional gradient we obtained from this study would be of great help to design sound strategies for Cloud Forest restoration. This is very important since little is known on Cloud Forest dynamics and because this habitat is considered one of the most endangered all over the world.