Evergreen Cloud Forest Research Articles

1108. Bulbophyllum boninense (Schltr.) J.J.Sm: Orchidaceae

SummaryBulbophyllum boninense (Schltr.) J.J.Sm. is illustrated and described. It is endemic to the Ogasawara (Bonin) Islands, subtropical oceanic islands in the Pacific Ocean belonging to Japan. This species grows as an epiphyte on trunks and as a lithophyte on rocks in evergreen cloud forest. It can be distinguished from closely related species by the following characters: dull yellow perianth lobes, no threads or ornaments at the apex of sepal and petal, a ciliate and pustulate petal, and a long stelidium that is semicircular at the base and curved anteriorly.

Biogeographical transitions in the Sierra Madre Oriental, Mexico, shown by chorological and evolutionary biogeographical affinities of passerine birds (Aves: Passeriformes)

AbstractAimTo locate areas of biogeographical transitions within the Sierra Madre Oriental (SMO), Mexican transition zone.LocationEastern Mexico (18° to 27° N – 90° to 96° W) and the Americas.MethodsWe deconstructed passerine fauna into biogeographical affinities to map their integration in the studied area. We defined and quantified two features of biogeographical affinity based on raw distributional range concordance (chorological affinity), and on ancestral state reconstruction of published phylogenies (evolutionary biogeographical affinity). Then, we divided the SMO into 500 m elevation intervals and 1.2° latitudinal belts. Point records of resident passerine birds were used to compute species turnover and to map the dominance and heterogeneity of biogeographical affinities along the gradient.ResultsConsidering the gradient of biogeographical affinities, we identified the sharpest transition at elevations of c. 1500 m from the southern evergreen cloud forests to the canyons of the middle Pánuco basin (c. 22° of latitude) and then turning eastwards, following the Pánuco river through the semi‐deciduous lowland forest to the river mouth in the Gulf of Mexico.Main conclusionsOur analysis allowed us to map a gradual pattern of variation based on a quantitative definition of biogeographical affinities. This approach is particularly useful for the analysis of rather small areas where a regional biota cannot be partitioned concomitantly with regionalization procedures. Our findings support previous suggestion of a middle elevation zone of mixture between Neotropical and Nearctic biotas, as shown by their chorotypes and cenocrons, and highlight the Pánuco river as a biogeographical boundary dividing northern and southern assemblages based on bird distributions in north‐eastern Mexico.

Exploring the effect of host tree identity on epiphyte bryophyte communities in different Canarian subtropical cloud forests

This study explores the host tree preferences of epiphyte bryophyte communities in two key types of evergreen cloud forests on La Gomera (Canary Islands, Spain): ericaceous versus broadleaved laurel forest. By comparing two pairs of tree species (Erica arborea and Myrica faya vs. Ilex canariensis and Laurus novocanariensis) that occur in both forest types, we quantitatively examined whether epiphyte-host relationships change with the type of forest. In 51 ancient forest stands, the low-trunk bryophyte composition on the two host tree groups was analysed with both non-parametric procedures and ordination analyses. Our results highlight that the influence of local environmental conditions on the structuring of epiphyte communities may be different depending on the host tree identity. Whilst the epiphyte composition of the host tree group formed by I. canariensis and L. novocanariensis differed significantly between forest types depending on solar exposure, we failed to find variations for the other host tree group, excepting in those localities wherein mist precipitation was extremely high. Our findings highlight the importance of the natural diversity of tree species along environmental gradients, as well as of water availability at different spatial scales for epiphytic bryophytes in montane cloud forests.

Flora vascular não-arbórea de uma floresta de grota na Serra da Mantiqueira, Zona da Mata de Minas Gerais, Brasil

A região da Serra Negra constitui um importante remanescente de floresta atlântica situado no sul da Zona da Mata mineira, na Serra da Mantiqueira, composta por um mosaico de campos rupestres (nos afloramentos de quartzito) a arbustais nebulares, florestas estacionais semideciduifólias a perenifólias e florestas nebulares, de ambientes inferomontanos a superomontanos ripícolas a interfluviais. A área de estudo é um fragmento de floresta de grota (floresta perenifólia ripícola), de aproximadamente 0,9 ha, situada no Cânion do Ribeirão do Funil, na Vila do Funil, município de Rio Preto, localizada no sul da Serra Negra. O presente trabalho foi realizado entre os anos de 2004 e 2009 e teve como objetivos o conhecimento da flora vascular não-arbórea, a discussão dos hábitos e habitats das plantas e a descrição da fisionomia do fragmento. Foram registrados 157 táxons de plantas vasculares (sendo 41 pteridófitas e 116 angiospermas), pertencentes a 48 famílias (10 de pteridófitas e 38 de angiospermas). As famílias de maior riqueza específica foram Orchidaceae, dentre as angiospermas, com 27 espécies e Pteridaceae, dentre as pteridófitas, apresentando 11 espécies. O hábito mais representativo foi o herbáceo (124 spp.), destacando-se as espécies epífitas (42 spp.), que perfazem cerca de 25% de todas as espécies registradas na área. Doze espécies estão incluídas na lista de espécies ameaçadas de extinção no estado de Minas Gerais (duas pteridófitas e 10 angiospermas). O elevado número de espécies encontradas em uma área consideravelmente pequena ressalta a importância deste fragmento para a diversidade da Serra Negra e aponta para a necessidade de implantação de um plano de ação para sua conservação.

Dos registros recientes del quetzal (Pharomachrus mocinno) en las Montañas del Este de Chiapas

El quetzal es un símbolo de la conservación de los bosques de niebla siempreverdes de Mesoamérica. Aquí, presentamos la descripción de dos registros obtenidos en las Montañas del Este de Chiapas, durante la estación reproductiva (abril) y no-reproductiva (agosto) de 2008. En la zona en donde se registraron estos quetzales ocurre una intensa pérdida forestal, por lo que sus hábitats reproductivo y no-reproductivo podrían estar en peligro de desaparecer en esta región.

Fragmentation, disturbance and tree diversity conservation in tropical montane forests

Summary Loss in forest cover associated with human activities leads to forest islands within a fragmented landscape. Anthropogenic disturbance may also directly alter tree species diversity. Habitat fragmentation and disturbance may have implications for biodiversity conservation and can affect a variety of population and community processes over a range of temporal and spatial scales. Effects are manifest both within and between fragments. The complexity of this process challenges the predictive value of simple models based on island biogeographical theory. We analysed data on tree species diversity from 195 field plots in 16 tropical montane forest fragments in the Highlands of Chiapas, Mexico. Within this area we identified five community types. Variation in species diversity between fragments in each community was analysed by fitting linear models in which area, core area, edge/area ratio, and mean proximity index were related to mean plot diversity. Variations within fragments were then analysed using linear mixed‐effects models in which the fixed effects were considered to be proximity to edge, canopy closure and a degradation index, whereas fragment‐level variation was modelled as a random effect. Effects of fragmentation per se, defined as the reduction in area and connectivity between fragments, were not detectable. Within‐fragment effects, however, were evident. Disturbance was associated with lower tree diversity at a local scale, and a notable impact on late successional species. While not statistically detectable, we expected fragmentation per se to be acting to reduce diversity in the long term. We therefore complemented our analysis by calculating the theoretical loss in species when the number of tree stems in a fragment was halved for each community type using resampled accumulation curves. These models predicted a maximum loss in transitional forest (12 species lost) and evergreen cloud forest fragments (seven to nine species lost) and a minimum loss in oak forest fragments (three species lost). Synthesis and applications. Our results call into question the utility of island theory when setting conservation priorities for tree species. In our study region, and elsewhere, tree diversity is most immediately threatened by the effects of within‐fragment disturbance. The few remaining areas of intact native forests should be prioritized for conservation regardless of their size and connectivity. If diversity is conserved within these fragments, the short‐term effects of landscape‐scale change may be minimized. They may then be reversed if long‐term restoration initiatives can be implemented.

Impacts of the loss of neotropical highland forests on the species distribution: a case study using resplendent quetzal an endangered bird species

We evaluated the impacts of land-cover changes of evergreen cloud forests on the distribution of quetzals in the four mountain regions of Chiapas, Mexico. The land-cover changes were estimated comparing satellite images of 1970 and 2000. We also simulated the amount of remnant forests 50 years in the future. The past and the current distributions of quetzals were based on literature records and recent field surveys. Our results showed that in 1970 the forests occupied 973 km2, and in 2000, 312 km2, and annual loss from 3.34 to 6.85%. Our simulation suggests that 50 years from now, only one region will maintain evergreen cloud forests. In addition, we documented literature reports of 39 forests inhabited by quetzals, but in 2001 there remained 11 small-isolated forests. In order to guarantee the survival of this species, conversation efforts must be made to protect the quetzal and its habitat throughout the entire Mesoamerica region.

Estimations of amounts of soil organic carbon and fine root carbon in land use and land cover classes, and soil types of Chiapas highlands, Mexico

Amounts of organic carbon in the mineral soil (SOC) and fine-root (<5 mm) carbon (RC) were quantified, when possible down to 1 m depth, in 150 soil profiles from 39 sites in the highlands of Chiapas, Mexico. The sampling sites were classified and grouped according to the following soil type: Leptosols, weathered soils (Ferralsols, Acrisols, Lixisols and Nitosols), Luvisols and Cambisols/Phaeozems. Likewise, they were classified in the following groups with respect to land use/land cover (LU/LC): oak–evergreen cloud forest, fragmented forest, pine and pine–oak forest, and open land (cultivated land and pasture). No clear influence of soil-type grouping on amounts of SOC was revealed, between soil-type groups (soil type). The weathered soils had higher amounts of SOC and RC in the upper 50 cm than the other soil types and the lowest amounts of SOC and RC in the 50–100 cm layers. The LU/LC groups showed marked differences in amounts of SOC. Open land had between 20 and 60% less soil carbon than the different types of forests. Oak–evergreen cloud forest had the largest amounts of SOC at all depths. The differences in amounts of carbon (SOC and RC) between oak–evergreen cloud forest and the other LU/LC classes were proportionally larger in the 50–100 cm layer. This suggests that the amounts of SOC in deep soil layers may be influenced by changes in LU/LC. The considerably smaller amounts of SOC and RC, 174 and 38.5 Mg ha −1, and 31 and 24.8 Mg ha −1, exhibited in open land compared to oak–evergreen cloud forest and pine and pine–oak forests, respectively, suggest that conversion of forests to open land reduces SOC and RC. Despite the magnitude of the differences, evaluation with ANOVA (nested design) did not reveal a statistically significant influence of LU/LC. The large spatial variability in amounts of soil carbon prevented precise estimates. Changes induced by a gradient in altitude among the plots may have contributed to the large variability between the plots.

Land-Use Change and Carbon Flux Between 1970s and 1990s in Central Highlands of Chiapas, Mexico.

/ We present results of a study in an intensively impacted and highly fragmented landscape in which we apply field-measured carbon (C) density values to land-use/land-cover (LU/LC) statistics to estimate the flux of C between terrestrial ecosystems and the atmosphere from the 1970s and 1990s. Carbon densities were assigned to common LU/LC classes on vegetation maps produced by Mexican governmental organizations and, by differencing areas and C pools, net C flux was calculated from the central highlands of Chiapas, Mexico, during a 16-year period. The total area of closed forests was reduced by half while degraded and fragmented forests expanded 56% and cultivated land and pasture areas increased by 8% and 30%, respectively. Total mean C densities ranged from a high of 504 tons C/ha in the oak and evergreen cloud forests class to a low of 147 tons C/ha in the pasture class. The differences in total C densities among the various LU/LC classes were due to changes in biomass while soil organic matter C remained similar. We estimate that a total of 19.99 thick similar 10(6) tons C were released to the atmosphere during the period of time covered by our study, equal to approximately 34% of the 1975 vegetation C pool. The Chiapas highlands, while comprising just 0.3% of Mexico's surface area, contributed 3% of the net national C emissions. KEY WORDS: Land use; Land cover; Carbon flux; Forests; Chiapas highlands; Mexico

Studies in Neotropical paleobotany. XIII. An Oligo‐Miocene palynoflora from Simojovel (Chiapas, Mexico)

A plant microfossil assemblage of 24 identified and five unknown pollen and spore types is reported from the early Miocene La Quinta Formation near Simojovel, Chiapas, Mexico. The taxa group into seven paleocommunities representing versions of the modern mangroves (Pelliciera, Rhizophora), swamp and lowland riparian forest (Ceratopteris, Crudia, Pachira), tropical rain forest (Selaginella, cf. Antrophyum, Pteris, Sphaeropteris/Trichipteris, cf. Aguiaria, Crudia, Guarea, Pachira), lower montane rain forest (Alfaroa/Oreomunnea, possibly Eugenia), evergreen cloud forest [Picea, Pinus, Podocarpus, Ericaceae (possibly Cavendishia/Vaccinium)], evergreen seasonal forest (Hymenaea, Ilex, possibly Eugenia), and tropical deciduous forest (Cedrela). Elements of arid and high-elevation habitats were absent or few, and northern temperate elements (Picea, Pinus?) were few or rare. Paleoelevations are estimated at 1000-1200 m (present average 2000 m, maximum 3004 m), MAT (mean annual temperature) at least as warm as the present 24°C, and annual rainfall near the present ∼2500 mm but more evenly distributed. The La Quinta (Simojovel) and other Tertiary floras from the region reflect a trend toward higher altitudes, more seasonal rainfall, cooling tempertures, increased introduction of cool-temperate elements from the north after ∼15 Ma (million years), and increased introduction of tropical elements from the south after completion of the isthmian land bridge ∼3.5 Ma ago.

Análisis florístico sucesional en la estación biológica Cerro Huitepec, Chiapas, México

Se presenta una lista florística y una descripción de la vegetación de seis comunidades sucesionales: zacatonal, matorral, bosque incipiente, bosque sucesional intermedio, bosque de encino y bosque de neblina en la Estación Biológica Cerro Huitepec, San Cristóbal de Las Casas, Chiapas. El total de la flora comprende 83 familias, 186 géneros y 315 especies; 10% de ellas fueron herbáceas anuales, 50% herbáceas perennes (incluyendo bejucos y helechos), 20% arbustos, 17% árboles del sotobosque y 3% árboles del dosel. El análisis de similitud (índice de Jaccard) permitió reconocer tres grupos de vegetación: el primero definido por especies predominantemente pioneras o sucesionalmente tempranas, típicas del zacatonal y del matorral, que tienen 58% de semejanza florística; el segundo incluye los elementos del bosque incipiente y el bosque sucesional intermedio, compartiendo 52% de su flora y en el que destacaron las plantas sucesionales intermedias; el último grupo formado por el bosque de neblina y el bosque de encino, que tienen en común 57% de la composición florística, principalmente de especies sucesionales intermedias y tardías. En la Estación Biológica Cerro Huitepec está representada 32% de la riqueza florística estimada para la región ubicada por encima de los 2000 m de altitud en el centro del estado. Sin embargo, debido a la baja densidad de las poblaciones de varias especies y a las tasas elevadas de deforestación que prevalecen alrededor, es probable la ocurrencia de algunas extinciones locales en el futuro cercano, por lo que es necesario diseñar estrategias apropiadas para su manejo y conservación.

A rapid method for the assessment of the macromycota. The fungal community of an evergreen cloud forest as an example

The macromycota of an evergreen cloud forest was described using a simple method, intended to minimize taxonomic work but still provide an accurate account of diversity. The method showed that the fungal community in the area is spatially structured and that area sampled limited the recording of fungal richness in this study. Parameters derived from the Clench equation suggest that an area of 1 ha will maximize the proportion of recorded taxa and minimize sampling effort.Key words: fungal diversity, macrofungal communities, tropical mycoecology, El Triunfo.

A rapid method for the assessment of the macromycota. The fungal community of an evergreen cloud forest as an example

A rapid method for the assessment of the macromycota. The fungal community of an evergreen cloud forest as an example

Diurnal patterns of water potential in the evergreen cloud forests of the Kaimai Ranges, North Island, New Zealand

Abstract Water potentials were measured on six species of evergreen trees growing at a range of altitudes, including the cloud zone, on two ridges in the Kaimai Ranges. Diurnal sampling at intervals throughout the summer showed little evidence of plant water stress. Dawn potentials were about -0.1 MPa and minimum potentials were down to -1.2 MPa except in Quintinia acutifolia, a seral shrub. This species yeilded low dawn potentials (-0.6 MPa) at a 600 m a.s.l. site which was below the cloud zone. Plants of unhealthy appearance growing on poor sites had lower potentials than healthy plants on adjacent good sites. Fog occurrence produced higher dawn potentials but had no effect on daily minimum potentials. The results contrast with leaf conductance studies in the same area which showed severe stress with rapid afternoon stomatal closure. It is suggested that the fog promotes soil waterlogging leading to water stress which is reflected in stomatal sensitivity but not shoot water potential.