RESUMO
Abandonment of agricultural lands promotes the global expansion of secondary forests, which are critical for preserving biodiversity and ecosystem functions and services. Such roles largely depend, however, on two essential successional attributes, trajectory and recovery rate, which are expected to depend on landscape-scale forest cover in nonlinear ways. Using a multi-scale approach and a large vegetation dataset (843 plots, 3511 tree species) from 22 secondary forest chronosequences distributed across the Neotropics, we show that successional trajectories of woody plant species richness, stem density and basal area are less predictable in landscapes (4 km radius) with intermediate (40-60%) forest cover than in landscapes with high (greater than 60%) forest cover. This supports theory suggesting that high spatial and environmental heterogeneity in intermediately deforested landscapes can increase the variation of key ecological factors for forest recovery (e.g. seed dispersal and seedling recruitment), increasing the uncertainty of successional trajectories. Regarding the recovery rate, only species richness is positively related to forest cover in relatively small (1 km radius) landscapes. These findings highlight the importance of using a spatially explicit landscape approach in restoration initiatives and suggest that these initiatives can be more effective in more forested landscapes, especially if implemented across spatial extents of 1-4 km radius.
Assuntos
Ecossistema , Florestas , Biodiversidade , Árvores , PlantasRESUMO
The tropical dry forest (BTS) of Yucatan Peninsula has been managed for centuries, but the relationship between these management efforts and their effects on trees diversity has not been fully understood. The aim of this study was to evaluate the effect of forest management (thinning, harvesting and enrichment of species), in the structure of secondary vegetation derived from dry tropical forests, in two communities in Calakmul, Campeche, Southeast Mexico. We analyzed changes in the composition, species richness, species diversity, and structure in secondary vegetation subject to following types of management: (1) secondary vegetation with beekeeping management (MA), secondary vegetation with forest management (MF), natural secondary vegetation (SM) and tropical dry forest (BTS). The species composition was similar between secondary vegetation managed and unmanaged. On the other hand, between managed secondary vegetation and BTS there were differences in species composition. Species richness was not different between all conditions. MA showed the lowest species diversity and presented higher average density (5 413±770.26 ind.ha-1).MF had lowest average density (3 289 ± 1 183.60 ind.ha-1). BTS showed the highest average basal area (24.89 ± 1.56 m2.ha-1) regarding the other conditions. We concluded that is necessary to keep monitoring the managed areas to detect effects of management that may be adverse or favorable to conservation of floristic diversity of BTS.
Assuntos
Biodiversidade , Conservação de Recursos Energéticos/métodos , Agricultura Florestal/métodos , Florestas , Árvores/fisiologia , Clima Tropical , Análise de Variância , Criação de Abelhas/métodos , Análise por Conglomerados , Monitorização de Parâmetros Ecológicos/métodos , México , Especificidade da EspécieRESUMO
Silvopastoral systems support local ecological and economical features as they enhance conservation of floral and faunal communities. As other animal communities, avifauna may be a good representative of habitat alterations, both as the species and functional levels. In order to attend the initiative of Mesoamerican Biological Corridor initiative (CBM) in the state of Tabasco, we studied the diversity of birds in two silvopastoral systems: scattered trees in pastures (ADP), and trees in boundary-hedgerows (AL). For this, we applied the fixed radius counting point method in three priority sites in Tabasco's CBM during the dry and wet season of 2011, and a total of 56, 60 and 62 points were evaluated in Huimanguillo, Tenosique and Tacotalpa, respectively. We observed 2 084 individuals of 154 species (79-89% of expected diversity) and 36 bird families. We detected 92, 87 and 85 species in Huimanguillo, Tenosique and Tacotalpa, respectively, including 35 protected species, of which 23, 19 and 16 in each locality, respectively. All sites showed high diversity (H' ≥ 3.20), low species dominance (D ≥ 0.08) and high equitability (J ≥ 0.77). Species composition showed differences between sites, being most similar Tacotalpa and Tenosique. Ten species were considered characteristic for sites. Although the silvopastoral system did contain protected species, the low diversity and the early successional character of the arboreal components were not attractive to frugivorous bird species. Diversification with native trees can improve the systems to create a complementary habitat and to increase landscape connectivity. The management of silvopastoral practices on cattle dominated landscapes in Tabasco could improve its ecological quality, and thus achieve the CBM's objectives ofbiodiversity conservation combined with human economic activities.
Assuntos
Biodiversidade , Aves/classificação , Animais , Bovinos , México , Densidade Demográfica , Estações do Ano , Clima TropicalRESUMO
Ecological indicators of habitat and biodiversity in a Neotropical landscape: multitaxonomic perspective. The use of indicator species to characterize specific ecological areas is of high importance in conservation/restoration biology. The objective of this study was to identify indicator species of diverse taxa that characterize different landscape units, and to better understand how management alters species composition. We identified two ecomosaics, tropical rain forest and the agricultural matrix, each one comprised of four landscape units. The taxonomic groups studied included birds (highly mobile), butterflies (moderately mobile), terrestrial gastropods (less mobile) and trees (sessile). Sampling efficiency for both ecomosaics was > or = 86%. We found 50 mollusks, 74 butterflies, 218 birds and 172 tree species, for a total of 514 species. Using ordination and cluster analysis, we distinguished three habitat types in the landscape: tropical rainforest, secondary vegetation and pastures with scattered trees and live fences. The InVal (> or = 50%) method identified 107 indicator species, including 45 tree species, 38 birds, 14 butterflies and 10 gastropods. Of these, 35 trees, 10 birds, four butterflies and eight gastropods were forest indicators. Additionally, 10, 28, 10 and two species, respectively per group, were characteristic of the agricultural matrix. Our results revealed a pattern of diversity decrease of indicator species along the rainforest-secondary forest-pasture gradient. In the forest, the gastropods Carychium exiguum, Coelocentrum turris, Glyphyalinia aff. indentata y Helicina oweniana were significantly correlated (p < 0.05) with 90% of the other groups of flora and fauna indicator species. These findings suggest that gastropods may be good indicators of forest habitat quality and biodiversity. The secondary vegetation is an intermediate disturbance phase that fosters high diversity in the agricultural matrix. We exemplify a multitaxa approach, including mesofauna, for ecological monitoring of agricultural landscapes.
Assuntos
Biodiversidade , Aves/classificação , Borboletas/classificação , Ecossistema , Monitoramento Ambiental/métodos , Gastrópodes/classificação , Árvores/classificação , Animais , Clima TropicalRESUMO
Resumen Los estudios detallados para comprender como los bosques neotropicales se reestablecen en el tiempo, a través de la sucesión secundaria aún resultan necesarios. Entre los mecanismos de regeneración que actúan en los bosques tropicales, el rebrote de árboles predomina en especies leñosas, con la ventaja de reiniciar el crecimiento de raíces establecidas, que permiten restituir el dosel forestal. El objetivo de este estudio fue identificar y cuantificar las especies arbóreas con capacidad de rebrote en distintas etapas de la sucesión secundaria (barbecho) después del sistema agrícola tradicional de milpa, comparadas con las comunidades del bosque tropical predominante en la Reserva de la Biósfera de Calakmul, y cómo influyen estas especies en la recuperación de la composición de este ecosistema. Se calculó el porcentaje de especies con y sin rebrote para cada etapa sucesional. Se registraron 13 972 individuos (32 % con rebrote y 68 % sin rebrote) y 168 especies (79 % con rebrote y 21 % sin rebrote), el porcentaje de individuos con rebrote va disminuyendo conforme avanza la edad de la sucesión. El número de individuos con rebrote y la composición de especies fueron significativamente diferentes entre etapas. Se puede concluir que la mayoría de especies arbóreas del bosque en Calakmul, presentan la capacidad de rebrotar, lo cual tiene influencia en el rápido proceso sucesional del bosque después de la roza-tumba y quema, restituyendo la cobertura y estructura forestal, así como la composición de las especies originales.(AU)
Abstract Detailed studies to understand recovering of Neotropical forests over time, through secondary succession, are still necessaries. Between acting mechanisms of regeneration in the tropical forests, the arboreal resprout predominates in woody species, with the advantage of restart the growth from still rooting plants, allowing the restoring of forest canopy. The study aim was to identify and quantify the tree species with resprouting capacity in different stages of secondary succession (tree-fallow) after the traditional milpa agricultural system, compared with tropical forest communities in the Calakmul Biosphere Reserve and, enlightening how these species influences the recovery of the composition of this ecosystem. Was calculated the proportions of species with or without resprouting by successional stage. There were 13 972 individuals (32 % resprouting and 68 % not resprouting) and 168 species (79 % resprouting and 21 % not resprouting), the percentage of individuals regrowing decreases as the successional stage progresses. The number of individuals resprouting and species composition were significantly different between successional stages. In conclusion, mostly arboreal species in the region of Calakmul, can regrow, which influences the successional development of the forest after slash-and-burn, helping to restore the coverage, structure, as well as species composition original.(AU)
Assuntos
Árvores , Produção Agrícola , Ecossistema Tropical , MéxicoRESUMO
ResumenEl bosque tropical seco (BTS) de la Península de Yucatán ha sido manejado por siglos, pero la relación del efecto del manejo sobre la diversidad de árboles no ha sido completamente entendida. El objetivo de este estudio fue evaluar el efecto del manejo forestal (aclareos, aprovechamiento y enriquecimiento de especies) en la estructura de la vegetación secundaria derivada de bosques tropicales secos, en dos comunidades en Calakmul, Campeche, Sureste de México. Se analizaron cambios en la composición, riqueza de especies, diversidad de especies y estructura en vegetación secundaria sujetas a los siguientes tipos de manejo: 1) vegetación secundaria con manejo apícola (MA), 2) vegetación secundaria con manejo forestal (MF), 3) vegetación secundaria sin manejo (SM) y bosque tropical seco (BTS). La composición de especies fue similar entre vegetación secundaria manejada y no manejada. Por otro lado, entre vegetación secundaria manejada y el BTS hubo diferencias en la composición de especies. La riqueza de especies no fue diferente entre todas las condiciones. La MA mostró la más baja diversidad de especies y presentó la mayor densidad promedio (5 413 ± 770.26 ind./ha). La MF tuvo la menor densidad promedio (3 289 ± 1 183.60 ind./ ha). El BTS mostró la mayor área basal promedio (24.89 ± 1.56 m2/ha) respecto a las demás condiciones. Se concluye que es necesario mantener el monitoreo de las áreas manejadas, para detectar efectos del manejo que pueden ser adversos o favorables para la conservación de la diversidad florística de los BTS.
Abstract:The tropical dry forest (BTS) of Yucatan Peninsula has been managed for centuries, but the relationship between these management efforts and their effects on trees diversity has not been fully understood. The aim of this study was to evaluate the effect of forest management (thinning, harvesting and enrichment of species), in the structure of secondary vegetation derived from dry tropical forests, in two communities in Calakmul, Campeche, Southeast Mexico. We analyzed changes in the composition, species richness, species diversity, and structure in secondary vegetation subject to following types of management: (1) secondary vegetation with beekeeping management (MA), secondary vegetation with forest management (MF), natural secondary vegetation (SM) and tropical dry forest (BTS). The species composition was similar between secondary vegetation managed and unmanaged. On the other hand, between managed secondary vegetation and BTS there were differences in species composition. Species richness was not different between all conditions. MA showed the lowest species diversity and presented higher average density (5 413±770.26 ind.ha-1).MF had lowest average density (3 289 ± 1 183.60 ind.ha-1). BTS showed the highest average basal area (24.89 ± 1.56 m2.ha-1) regarding the other conditions. We concluded that is necessary to keep monitoring the managed areas to detect effects of management that may be adverse or favorable to conservation of floristic diversity of BTS. Rev. Biol. Trop. 65 (1): 41-53. Epub 2017 March 01.
Assuntos
Árvores/fisiologia , Clima Tropical , Florestas , Agricultura Florestal/métodos , Conservação de Recursos Energéticos/métodos , Biodiversidade , Especificidade da Espécie , Análise por Conglomerados , Análise de Variância , Criação de Abelhas/métodos , Monitorização de Parâmetros Ecológicos/métodos , MéxicoRESUMO
Silvopastoral systems support local ecological and economical features as they enhance conservation of floral and faunal communities. As other animal communities, avifauna may be a good representative of habitat altera- tions, both as the species and functional levels. In order to attend the initiative of Mesoamerican Biological Corridor initiative (CBM) in the state of Tabasco, we studied the diversity of birds in two silvopastoral systems: scattered trees in pastures (ADP), and trees in boundary-hedgerows (AL). For this, we applied the fixed radius counting point method in three priority sites in Tabasco´s CBM during the dry and wet season of 2011, and a total of 56, 60 and 62 points were evaluated in Huimanguillo, Tenosique and Tacotalpa, respectively. We observed 2 084 individuals of 154 species (79-89% of expected diversity) and 36 bird families. We detected 92, 87 and 85 species in Huimanguillo, Tenosique and Tacotalpa, respectively, including 35 protected species, of which 23, 19 and 16 in each locality, respectively. All sites showed high diversity (H´≥3.20), low species dominance (D≥0.08) and high equitability (J≥0.77). Species composition showed differences between sites, being most similar Tacotalpa and Tenosique. Ten species were considered characteristic for sites. Although the silvopastoral system did contain protected species, the low diversity and the early successional character of the arboreal components were not attractive to frugivorous bird species. Diversification with native trees can improve the systems to create a complementary habitat and to increase landscape connectivity. The management of silvopastoral practices on cattle dominated landscapes in Tabasco could improve its ecological quality, and thus achieve the CBM´s objectives of biodiversity conservation combined with human economic activities.
Los sistemas silvopastoriles contienen rasgos ecológicos y económicos que contribuyen con la conservación de comunidades florísticas y faunísticas que en ellas se desarrollan. Entre otras comunidades faunísticas se encuentra la avifauna la cual es un grupo representativo de las alteraciones del habitat, tanto a nivel específico como grupo functional. Con el objetivo de atender la iniciativa de Corredor Biológico Mesoamericano en Tabasco, México, se analizó la diversidad de aves en dos sistemas silvopastoriles: árboles dispersos en potreros (ADP) y árboles en cercos o linderos (AL). Se aplicó el método de punto de conteo de radio fijo en tres sitios prioritarios del CBM de Tabasco, ubicados en los municipios: Huimanguillo, Tacotalpa y Tenosique. Los datos provienen de las estaciones seca y húmeda del 2011. Se registraron 2 084 aves de 154 especies (79-89% del esperado) y 36 familias. Se detectaron 92, 87 y 85 especies, incluyendo 35 protegidas, con 23, 19 y 16 en Huimanguillo, Tacotalpa y Tenosique, respectivamente. Todos los sitios mostraron alta diversidad (H’≥3.20), baja dominancia de especies (D≥0.08) y alta equidad (J≥0.77). La composición de especies mostró diferencias entre sitios, con mayor similitud entre Tacotalpa y Tenosique. Diez especies pueden considerarse características de los sitios. Aunque en los sistemas silvopastoriles se refugian aves protegidas, el componente arbóreo es poco diverso y corresponde a especies de sucesión secundaria temprana, lo que limita a las aves frugívoras y especialistas de bosque. Diversificar estos sistemas con árboles nativos puede mejorar estos hábitats complementarios e incrementar la conectividad del paisaje para cumplir con los objetivos del CBM en la conservación de la biodiversidad y provisión de bienes a las poblaciones humanas.
Assuntos
Animais , Bovinos , Biodiversidade , Aves/classificação , México , Densidade Demográfica , Estações do Ano , Clima TropicalRESUMO
Ecological indicators of habitat and biodiversity in a Neotropical landscape: multitaxonomic perspective. The use of indicator species to characterize specific ecological areas is of high importance in conservation/ restoration biology. The objective of this study was to identify indicator species of diverse taxa that characterize different landscape units, and to better understand how management alters species composition. We identified two ecomosaics, tropical rain forest and the agricultural matrix, each one comprised of four landscape units. The taxonomic groups studied included birds (highly mobile), butterflies (moderately mobile), terrestrial gastropods (less mobile) and trees (sessile). Sampling efficiency for both ecomosaics was ≥86%. We found 50 mollusks, 74 butterflies, 218 birds and 172 tree species, for a total of 514 species. Using ordination and cluster analysis, we distinguished three habitat types in the landscape: tropical rainforest, secondary vegetation and pastures with scattered trees and live fences. The InVal (≥50%) method identified 107 indicator species, including 45 tree species, 38 birds, 14 butterflies and 10 gastropods. Of these, 35 trees, 10 birds, four butterflies and eight gastropods were forest indicators. Additionally, 10, 28, 10 and two species, respectively per group, were characteristic of the agricultural matrix. Our results revealed a pattern of diversity decrease of indicator species along the rainforest-secondary forest-pasture gradient. in the forest, the gastropods Carychium exiguum, Coelocentrum turris, Glyphyalinia aff. indentata y Helicina oweniana were significantly correlated (p<0.05) with 90% of the other groups of flora and fauna indicator species. These findings suggest that gastropods may be good indicators of forest habitat quality and biodiversity. The secondary vegetation is an intermediate disturbance phase that fosters high diversity in the agricultural matrix. We exemplify a multitaxa approach, including mesofauna, for ecological monitoring of agricultural landscapes. Rev. Biol. Trop. 59 (3): 1433-1451. Epub 2011 September 01.
El uso de especies indicadoras para caracterizar unidades ecológicas específicas es de gran importancia en la biología de la conservación/restauración. El objetivo del estudio fue identificar desde una perspectiva multitaxonómica, las especies que caracterizan distintas unidades de un paisaje. Así, se diferenciaron dos ecomosaicos: bosque tropical lluvioso y matriz agropecuaria con cuatro unidades de paisaje cada uno. Se incluyeron cuatro grupos biológicos: aves (muy móviles), mariposas frugívoras diurnas (moderadamente móviles), gasterópodos terrestres (poco móviles) y árboles (sésiles). La eficiencia de muestreo en los ecomosaicos fue ≥86%. Se registraron 50 especies de moluscos, 74 de mariposas, 218 de aves y 172 de árboles, totalizando 514 especies. Mediante ordenamiento y agrupamiento, se diferenciaron tres tipos de hábitats: bosque tropical lluvioso, vegetación secundaria y potreros con árboles. Aplicando el método InVal (≥50%), se identificaron 107 especies indicadoras, de las cuales 45 fueron árboles, 38 aves, 14 mariposas y diez gasterópodos. De éstas, 35 especies de árboles, diez de aves, cuatro de mariposas y ocho de gasterópodos son indicadoras del bosque. Diez, veintiocho, diez y dos especies (de cada grupo respectivamente) caracterizaron a la matriz agropecuaria. En el bosque, los gasterópodos Carychium exiguum, Coelocentrum turris, Glyphyalinia aff. indentata y Helicina oweniana se correlacionaron significativamente (p<0.05) con 90% de las especies indicadoras. Estos gasterópodos pueden, además de diferenciar la calidad del hábitat, ser indicadoras de la biodiversidad del bosque. La vegetación secundaria representó una fase intermedia de perturbación que propicia alta riqueza en la matriz agropecuaria. De manera que se aporta una perspectiva multitaxonómica que incluye el papel de la mesofauna en el monitoreo ecológico de agropaisajes.