Soil macrofauna in areas with different ages after Pinus patula clearcutting / Macrofauna edáfica en áreas con diferentes edades después de la tala rasa de Pinus patula / Macrofauna do solo em áreas com diferentes Idades após o corte raso de Pinus patula

Abstract In Andean high montane areas, the establishment of exotic tree forests changes the soil dynamics and its biodiversity. Soil macrofauna act as indicators of ecosystem successional processes, and may have an important role in ecological restoration processes after clearcutting exotic tree plantations. The aim of the present study was to understand how soil macrofaunal assemblies change in areas with different ages post clearcutting of Pinus patula, and to identify the soil physico-chemical variables that better explain these variations. The macrofauna in a high montane forest was evaluated along with that of three areas with different ages post clearcutting: 0, 2.5, and 5 years after clearcutting (Yac). The effect of soil physico-chemical variables on macrofauna abundance was also evaluated. Macrofauna composition changed after clearcutting. Macrofauna abundance, richness, and diversity were lower in the 0 Yac area than in the other areas. Moreover, the macrofuna similarity to the reference forest did not increase with the years after clearcutting. This is due to the changes in soil characteristics, triggered by clearcutting. Slope, temperature, bulk density, real density, loam, pH, P, Na and K were the soil variales with a positive effect on the macrofauna abundance. These physico-chemical variables should be considered when designing restoration plans for Andean forest ecosystems. Moreover, Diplopoda, Coleoptera and Chilopoda might be useful to monitor and evaluate restoration processes after Pinus spp. clearcutting, because of their high abundance, diversity and relationship with environmental conditions.

Resumen El establecimiento de plantaciones forestales de especies exóticas cambia el ambiente edáfico y la biodiversidad del suelo, y es una de las mayores amenazas para el bosque de alta montaña. La macrofauna edáfica es un indicador de los procesos sucesionales del ecosistema y, consecuentemente, puede tener un rol importante en la restauración ecológica tras el proceso de tala rasa de estas plantaciones. El objetivo de este trabajo fue entender cómo la macrofauna cambia en áreas con diferentes edades después de la tala rasa de Pinus patula, e identificar las variables fisicoquímicas que mejor explican estas variaciones. Se evaluó la macrofauna en un bosque de alta montaña junto con tres áreas con diferentes edades después de la tala: 0, 2.5 y 5 años. También se evaluó el efecto de las características fisicoquímicas del suelo en la abundancia de macrofauna. La composicion de la macrofauna cambió después de la tala rasa. La abundancia, riqueza y diversidad fueron menores a la edad 0 después de la tala rasa que a las otras edades. Ademas, la similitud con el bosque de referencia no aumentó con el tiempo después de la tala, por los cambios en las características del suelo que ocurren como consecuencia de la tala. La pendiente, la temperatura, la densidad aparente, la densidad real, la textura del suelo, pH, P, Na y K tuvieron un efecto positivo en la abundancia de macrofauna. Estas variables fisicoquímicas deberían considerarse en el diseño de los planes de restauración de los ecosistemas de bosque andino. Además, Diplopoda, Coleoptera y Chilopoda podrían ser útiles para monitorear y evaluar los procesos de restauración después de la tala de Pinus spp., dada su alta abundancia, diversidad y relación con condiciones ambientales.

Resumo As florestas de árvores exóticas alteram as dinâmicas e biodiversidade do solo nas áreas andinas de alta montanha. A macrofauna do solo atua como indicador do processo de sucessão dos ecossistemas e pode ter um papel importante nos processos de restauração ecológica após o corte raso de plantações de árvores exóticas. O objetivo deste estudo foi entender como mudam as associações entre a macrofauna do solo em áreas com diferentes idades após o corte raso do pinheiro, Pinus patula, e identificar variáveis físico-químicas do solo que explicassem essas diferenças. Para isso avaliamos a macrofauna de uma floresta de alta montanha assim como a de três áreas com diferentes idades após o corte raso: 0; 2.5 e 5 anos após o corte raso (Yac). Também avaliamos o efeito das variáveis físico-químicas do solo na abundância da macrofauna. A composição da macrofauna mudou após o cote raso. A abundância, riqueza e diversidade da macrofauna foram menores na área com 0 Yac do que em outras áreas. Adicionalmente, a similaridade da macrofauna com a floresta de referência não aumentou em função dos anos após o corte raso. Isto é devido a mudanças nas características do solo desencadeadas pelo corte raso. A inclinação, temperatura, densidade aparente, densidade real, limo, pH, P, Na e K foram as variáveis do solo que tiveram um efeito positivo na abundância da macrofauna. Estas variáveis físico-químicas deveriam ser consideradas no projeto de planos de restauração para ecossistemas de floresta andinos. Adicionalmente, as ordens Diplopoda, Coleoptera e Chilopoda podem ser úteis para monitorar e avaliar o processo de restauração após o corte raso de Pinus spp. devido a sua alta abundância, diversidade e relação com as condições ambientais.

Management of the environmental restoration of degraded areas

The aim of this work was to study ecotechnology for the management of degraded areas originally covered by the Atlantic Rainforest and located at the coordinates 25º31'50''S, 9º09'30''W. The area included 12 islands, each consisting of six jute bags with 20 kg of substrate (cattle manure and soil transposed from forest fragments). In six of these bags, native plants and seeds were also included. Six additional islands were selected randomly in the vicinity as the control. The process of evaluation was monitored through the chemical and granulometric soil analysis and surveys of survival, biometrics, floristic and phytosociological vegetation. An improvement in soil properties was observed where the model was implemented, which could be attributed to the substrate and re-vegetation. In the floristic and phytosociological studies, out of the 118 identified species, 65 were observed in the first floristic inventory and 86 in the second floristic inventory with similarities between the subfields of 27.69% and 11.36%, respectively. The influence of the substrate seed bank in the implemented islands was also observed. Increased diversity was only significant in the subareas with the model. It was concluded that this technology was effective in accelerating the succession and promoting the beginning of the restoration.

Dinámica de nutrientes en plantaciones forestales de Azadirachta indica (Meliaceae) establecidas para restauración de tierras degradadas en Colombia / Nutrient dynamics in forest plantations of Azadirachta indica (Meliaceae) established for resto- ration of degraded lands in Colombia

Azadirachta indica is a tree species which use is steadily increasing for restoration of tropical and subtropical arid and degraded lands throughout the world. The objective of this research study was to evaluate the potential of these plantations as an active restoration model for the recovery of soils under desertification in arid lands of Colombia. Litter traps and litter-bags were installed in twenty 250m² plots. Green leaves and soil samples inside and outside this species plantations were taken, and their elemental concentrations were determined. Litterfall, leaf litter decomposition and foliar nutrient resorption were moni- tored for one year. The annual contributions of organic material, such as fine litterfall, represented 557.54kg/ha, a third of which was A. indica leaves. The greatest potential returns of nutrients per foliar litterfall were from Ca (4.6kg/ha) and N (2.4kg/ha), and the smallest potential returns came from P (0.06kg/ha). A total of 68% of the foliar material deposited in litter-bags disappeared after one year. The greatest release of nutrients was that of K (100%), and the least was that of N (40%). P was the most limiting nutrient, with low edaphic availability and high nutrient use efficiency from Vitousek´s index (IEV=3176) and foliar nutrient resorption (35%). Despite these plantations are young, and that they have not had forestry management practices, as an active restoration model, they have revitalized the biogeochemical cycle, positively modifying the edaphic parameters according to the increases in organic material, P and K of 72%, 31% and 61%, respectively. Furthermore, they improved the stability of aggregates and the microbe respiration rates. The forest plantation model with exotic species has been opposed by different sectors; however, it has been acknowledged that these projects derive many benefits for the restoration of biodiversity and ecosystemic functions. The conditions of severe land degradation demand the initial use of species, such as A. indica, that can adapt quickly and successfully, and progressively reestablish the biogeochemical cycle.

Azadirachta indica A. Juss (Nim) ha sido ampliamente empleada en procedimientos de restauración, por lo tanto se evaluó el potencial de sus plantaciones para restaurar tierras secas degradadas por sobrepastoreo, vía reactivación del ciclo biogeoquímico. En 20 parcelas de 250m², se instalaron trampas de hojarasca y litter-bags. Se tomaron muestras de hojas maduras y de suelos dentro y fuera de las plantaciones, y se determinaron sus contenidos elementales. Fueron monitoreados la caída de hojarasca, la descomposición de hojarasca y la reabsorción de nutrientes foliares durante un año. Los aportes anuales de hojarasca fina representaron 557.54kg/ha (33% hojas de Nim). Los mayores retornos potenciales de nutrientes vía foliar fue- ron de Ca (4.6kg/ha) y N (2.4kg/ha) y los menores de P (0.06kg/ha). El 68% del material se descompuso tras un año. La mayor liberación de nutrientes fue de K (100%) y la menor de N (40%). El P fue el nutriente más limitante, con baja disponibilidad edáfica y alta eficiencia en su uso según el Índice de Vitousek (IEV=3 176) y la reabsorción foliar (35%). Estas plantaciones juveniles demostraron efectividad en la reactivación del ciclo biogeoquímico, que mejoraron parámetros edáficos, según incrementos de materia orgánica, P y K; 72%, 31% y 61%, respectiva- mente. Además mejoraron la estabilidad de agregados y las tasas de respiración microbiana.

Dendrometry and litterfall of neotropical pioneer and early secondary tree species / Dendrometria e produção de serapilheira de espécies arbóreas neotropicais pioneiras e secundárias iniciais

The increased forest cover loss in the tropical and subtropical regions has stimulated the development of restoration methods through tree plantations. Based on the successional model of forest development the use of different successional groups can be seen as a strategy to accelerate the re-composition of forests and an attempt to recover ecological conditions prior to disturbance. Tree species have particular growth rates and ecological needs, and this knowledge is important in the development of high diversity models of forest restoration. The objective of this study was to compare the initial growth and litterfall of native pioneer versus early secondary tree species in a mixed plantation system, and to determine the relationships between guilds and measurements. The comparison among species and guilds was made based on dendrometric and allometric parameters, and in terms of annual litterfall. The study was carried out in the Guarita Indian Area, Tenente Portela, Rio Grande do Sul, Brazil. Dendrometry of seven species was evaluated, including the pioneer tree species Mimosa scabrella Bentham, Trema micrantha (L.) Blume, Schinus molle L., Enterolobium contortisiliquum (Vell.) Morong, and the early secondary tree species Peltophorum dubium (Spreng.) Taub., Cedrela fissilis Vell. and Tabebuia alba (Cham.) Sandwith. The litterfall was quantified for the first six species. The pioneer tree species exhibited higher average height, stem diameter and crown width than the early secondary tree species. The pioneer species (except E. contortisiliquum) showed also higher values of average annual litterfall. A positive interspecific correlation between stem diameter and annual litterfall was observed. The data indicate that the choice of the species and guilds is significant to the quality of the restoration. Nevertheless, the aboveground architecture may depend on species-specific allometric characteristics and a distinction among guilds was not observed.

A perda de cobertura florestal em regiões tropicais e subtropicais tem motivado o desenvolvimento de modelos de restauração florestal através do plantio de espécies arbóreas. Tendo como base o modelo sucessional, o uso concomitante de espécies de diferentes categorias sucessionais pode ser visto como uma estratégia no sentido de acelerar o retorno a condições prévias à perturbação. As espécies arbóreas têm ritmos de crescimento e necessidades ecológicas diferentes e este conhecimento é importante para o desenvolvimento de modelos de restauração florestal com alta diversidade. O objetivo deste estudo foi comparar o crescimento inicial e a queda anual de serapilheira de espécies arbóreas nativas pioneiras e secundárias iniciais em um sistema heterogêneo de plantio, determinando a correlação entre categorias sucessionais e medidas. A comparação entre espécies e categorias foi realizada considerando parâmetros dendrométricos e alométricos, e a queda anual de serapilheira. O estudo foi conduzido na Área Indígena Guarita, Tenente Portela-RS, Brasil, para sete espécies, incluindo as pioneiras arbóreas Mimosa scabrella Bentham, Trema micrantha (L.) Blume, Schinus molle L., Enterolobium contortisiliquum (Vell.) Morong, e as secundárias iniciais Peltophorum dubium (Spreng.) Taub., Cedrela fissilis Vell. e Tabebuia alba (Cham.) Sandwith. A avaliação da produção da serapilheira foi feita nas primeiras seis espécies. As espécies pioneiras apresentaram maiores médias de altura, diâmetro do fuste e largura da copa. As pioneiras (com exceção de E. contortisiliquum) também apresentaram valores médios mais elevados de queda de serapilheira. Uma correlação interespecífica entre diâmetro do caule e produção anual de serapilheira foi observada. Os dados indicam que a escolha das espécies e guildas tem influência significativa sobre a qualidade da restauração. Entretanto, a arquitetura da parte aérea depende das características alométricas específicas das...

Atributos vitales de especies leñosas en bordes de bosque altoandino de la Reserva Forestal de Cogua (Colombia)

Vital traits of woody species in High Andean forest edges of the Cogua Forest Reserve (Colombia). The Cogua Forest Reserve was studied throughout eight months to detect the existence of functional species-groups associated with edge wood forest. A second goal was to determine which species were the most successful in edge areas and their particular vital traits. The regeneration and growth of the forest patches to the adjacent matrix depends on the establishment of these species and their tolerance to both habitats. Three types of High Andean edge forest were studied. Two forest patches were chosen for each of the three edge types: Chusquea scandens edge, "paramune" and old-edge; the name of the latter was given because of its advanced successional state. in each patch, the vegetation was evaluated in two 60 m transects perpendicular to the edge and along the matrix-edge-interior gradient of the forest. All woody species were identified and counted to determine their abundance. A total of nine species were chosen as representative of High Andean forest edges in the reserve, because of their high abundance in this environment, their presence in both patches of each edge type and their ability to colonize the adjacent matrix. Each species was evaluated using 20 vital attributes of individual, leaf, and reproductive traits. Six species groups were found through a Correspondence Analysis. However, all nine species have high variation and plasticity levels for the attributes, even inside the groups. This trend suggests that while they are not clearly differentiated functional groups, they probably are representing different strategies within a single functional group of great plasticity. Tibouchina grossa and Pentacalia Pulchella are found in all edge and matrix types; the other species are found in all edge types, except by Gaiadendron punctatum and Weinmannia tomentosa, absent in the Chusquea scandens edge. All nine species are important elements in the restoration of forest edges, mainly where they are more abundant, evidencing their success in the particular conditions of an edge type. Miconia ligustrina and M. squamulosa are the most relevant species in the Chusquea scandens edge and matrix; while G. punctatum, P. pulchella, W. tomentosa, W. balbisiana and especially Macleania rupestris, are more important in the paramune edge and matrix; Hedyosmum bonplandianum is more important in the edge than in the matrix regeneration, while T. grossa is the most successful edge and matrix regeneration species, because it is the most abundant and has high levels of tolerance, vegetative reproduction and litter production. These features are related with a high rate of tissue replacement, as well as a persistent seed bank with smaller and more numerous seeds, evidence of its high fecundity. Rev. Biol. Trop. 56 (2): 705-720. Epub 2008 June 30.

En la Reserva Forestal de Cogua (Colombia), estudiamos mediante transectos la vegetación leñosa en dos parches de bosque altoandino para tres tipos de borde: chusque, paramizado y antiguo (este último denominado así por presentar un estado sucesional más avanzado). Seleccionamos como especies típicas de borde las que tenían mayor abundancia en esta zona, presentes en ambos parches del borde y capaces de colonizar la matriz adyacente. Se obtuvo un conjunto de nueve especies a las cuales se les evaluaron 20 atributos vitales, generando seis grupos mediante un análisis de agrupamiento (cluster): 1) Weinmannia balbisiana-W. tomentosa, 2) Gaiadendron punctatum-Hedyosmum bonplandianum, 3) Miconia ligustrina-M. squamulosa, 4) Macleania rupestris, 5) Pentacalia pulchella y 6) Tibouchina grossa. La amplia variación y plasticidad de las especies estudiadas en cuanto a los atributos analizados, conduce a pensar que los conjuntos obtenidos no obedecen a grupos funcionales claramente diferenciados, sino más bien a estrategias diferentes y que estas especies podrían hacer parte de un solo grupo funcional de gran plasticidad. T. grossa es la especie de borde más exitosa en la reserva, dados sus altos valores de abundancia, tolerancia fisiológica, reproducción vegetativa, producción de hojarasca y producción de semillas pequeñas, numerosas, formadoras de un banco de semillas persistente que evidencian su alta fecundidad.