The water and energy exchange of a shaded coffee plantation in the lower montane cloud forest zone of central Veracruz, Mexico

The water and energy fluxes of a shaded coffee plantation in the lower montane cloud forest (LMCF) zone of central Veracruz, Mexico, were measured over a two-year period (September 2006-August 2008) using the eddy covariance method. Complementary measurements of throughfall and stemflow were made to study rainfall interception. The sum of the observed sensible (H) and latent (λE) heat fluxes was almost 95% of the net radiation (

National assessments of species vulnerability to climate change strongly depend on selected data sources

Aim: Correlative species distribution models (SDMs) are among the most frequently used tools for conservation planning under climate and land-use changes. Conservation-focused climate change studies are often conducted on a national or local level, and can use different sources of occurrence records (e.g., local databases, national biodiversity monitoring) collated at different geographic extents. However, little is known about how these restrictions in geographic space (i.e., Wallacean shortfall) can lead to restrictions in environmental space (i.e. Hutchinsonian shortfall) and accordingly affect conclusions about a species’ vulnerability to climate change. Location: Americas with focus on Mexico Methods: We present an example study constructing SDMs for three Mexican tree species (Alnus acuminata, Liquidambar styraciflua and Quercus xalapensis) using datasets collated at a global (Americas), national (Mexico) and local (cloud forests of eastern Mexico) level to demonstrate the potential effects of a Wallacean shortfall on the estimation of the environmental niche - and thus on a Hutchinsonian shortfall -, its projection in space and time and, consequently, on species’ potential vulnerability to climate change. Results: The consequence of using the three datasets was species-specific and strongly depended on the extent to which the Wallacean shortfall affected estimations of environmental niches (i.e., Hutchinsonian shortfall). Where restrictions in geographic space lead to an underestimation of the environmental niche, vulnerability to climate change was estimated to be substantially higher. Additionally, the restrictions in geographic space may increase the likelihood of issues with non-analog climates, increasing model uncertainty. Main Conclusion: We recommend to assess the extent to which a species’ entire realized environmental niche is captured within the target conservation area, and increasing the geographic extent, if needed, to account for environments and occurrences reflecting potential future conditions. This way, the risk of underestimating the climatic potential of the species (i.e., Hutchinsonian shortfall), as well as the errors induced by extrapolation into “locally novel” climates, can be minimised

Importancia ambiental de los agroecosistemas cafetaleros bajo sombra en la zona central montañosa del estado de Veracruz, México

The shade-grown coffee agroecosystem has contributed to mitigate the loss of ecosystem services provided by the tropical cloud forest in the mountainous central region of Veracruz. This is largely due to the fact that this cultivation type is friendly with that forest ecosystem. Although, despite the multiple services that this cultivation provides, coffee production has been losing importance among producers. The objective of this research was to identify the farmers' perception about the importance of growing coffee under shade in the provision of environmental services and whether this influences their willingness to maintain this agroecosystem. This perception is analyzed in the context of regional changes in temperature and precipitation, which could be related to transformations in forest cover. In order to address the perceptions a case study method was employed. The case study was carried out by analyzing the results of a questionnaire administered to 51 producers of the locality of La Orduña, Coatepec, Ver. In order to study the historical changes in regional precipitation and temperature, data from three climatic stations close to La Orduña were employed. Data were analyzed with the procedures recommended by the World Meteorological Organization. Results display changes in regional climate, as well as the producers' identification of the main environmental benefits that shade-grown coffee provide. Similarly, they show their willingness to maintain this culture, providing government policies financially remunerate the environmental services that this agroecosystem supply.El agroecosistema cafetalero bajo sombra ha contribuido a mitigar la pérdida de los servicios ambientales que provee el bosque mesófilo en la región central montañosa de Veracruz. Esto se debe en gran medida a que es un cultivo amigable con dicho ecosistema forestal. Sin embargo, a pesar de los múltiples servicios que proporciona, la cafeticultura ha estado perdiendo importancia entre los productores. El objetivo de este trabajo fue identificar la percepción de los productores sobre la importancia del cultivo de café bajo sombra en la prestación de servicios ambientales y si esto influye en su disposición a conservarlo. Esta percepción se analiza en el contexto regional de cambios en la temperatura y precipitación, que podrían estar relacionados con transformaciones en la cobertura forestal. Para abordar la percepción se utilizó el método de estudio de caso. El caso se documentó con la aplicación de un cuestionario a 51 productores de la localidad de La Orduña, Coatepec, Ver., México. Para estudiar los cambios históricos de la precipitación y la temperatura regional, se utilizaron los datos de tres estaciones climatológicas cercanas a la comunidad. Los datos se analizaron con los procedimientos sugeridos por la Organización Meteorológica Mundial. Los resultados muestran cambios en el clima regional, así como la identificación de los principales beneficios ambientales de los cafetales por parte de los productores. De igual forma, muestran su disposición a mantener dicho cultivo, siempre que las políticas gubernamentales retribuyan económicamente los servicios ambientales que proporciona este agroecosistema

Relações hídricas e trocas gasosas em vinhedo sob cobertura plástica Water relations and leaf gas exchange in vineyard with plastic overhead cover

No presente estudo, determinaram-se as influências da cobertura plástica impermeável (CP) sobre a demanda evaporativa atmosférica e o potencial da água no solo, bem como as conseqüências destas sobre as trocas gasosas foliares (fotossíntese, condutância estomática e transpiração) e o potencial da água na folha da videira. As avaliações foram realizadas nos ciclos 2005/06 e 2006/07, em um vinhedo da cv. Moscato Giallo, conduzido em "Y", com cobertura plástica impermeável tipo ráfia (160 mm), em 12 fileiras com 35 m, deixando-se cinco fileiras sem cobertura (controle). Em ambas as áreas, avaliou-se o microclima quanto à temperatura do ar, umidade relativa do ar, radiação fotossinteticamente ativa e velocidade do vento, próximos ao dossel vegetativo. A CP aumentou a disponibilidade hídrica no solo nas entrelinhas e restringiu-a nas linhas, sobretudo em profundidades mais superficiais (0-10 cm). A CP também diminuiu a demanda evaporativa atmosférica, principalmente pela redução da velocidade do vento (-90%), aumentando o potencial da água na folha e a condutância estomática. De modo geral, a CP pode favorecer a condição hídrica e elevar a capacidade de assimilação de carbono em videiras.<br>This study evaluated the plastic overhead cover (POC) effect on evaporative demand of atmosphere and soil water content, as well as their consequences on gas exchange (photosynthesis, stomatal conductance and transpiration) and leaf water potential in grapevine. The experiment was carried out during the 2005/06 and 2006/07 seasons, in a vineyard of 'Moscato Giallo', trained in "Y" and covered with an impermeable plastic cloth (2.65 m x 160 mm), in 12 rows with 35 m, with five rows left uncovered (control). In both areas, the microclimate was evaluated, in terms of air temperature, air relative humidity, radiation photosynthetically active and wind speed above the canopy. The POC increased the soil water content between rows and restricted it in the most superficial depths of rows (0-10 cm). The POC also decreased the evaporative demand of atmosphere, mainly by reducing wind speed (-90%), which increased the leaf water potential and stomatal conductance. In this way, POC can favor water conditions and increase leaf carbon assimilation in grapevines

Microclimatic characterization and productivity of coffee plants grown under shade of pigeon pea in Southern Brazil Caracterização microclimática e produtividade de cafeeiros sombreados com guandu no Sul do Brasil

Recent studies on coffee (Coffea arabica L.) cultivation in agroforestry systems in Southern Brazil have shown the potential of partial shading to improve management of this crop. The objective of this work was to evaluate microclimatic conditions and their effects on coffee production of plants shaded with pigeon pea (Cajanus cajan) in comparison to unshaded ones, from May 2001 to August 2002 in Londrina, State of Paraná, Brazil. The appraised microclimatic characteristics were: global radiation, photosynthetic and radiation balance; air, leaf and soil temperatures; and soil humidity. Shading caused significant reduction in incident global solar radiation, photosynthetically active radiation and net radiation, and attenuated maximum leaf, air and soil temperatures, during the day. Shade also reduced the rate of cooling of night air and leaf temperatures, especially during nights with radiative frost. Soil moisture at 0-10 cm depth was higher under shade. The shaded coffee plants produced larger cherries due to slower maturation, resulting in larger bean size. Nevertheless, plants under shade emitted less plagiotropic branches, with smaller number of nodes per branch, and fewer nodes with fruits, resulting in a large reduction in coffee production. These results show the need to find an optimal tree density and management that do not compromise coffee production and protect against extreme temperatures.<br>Recentes estudos sobre cafeeiros (Coffea arabica L.) cultivados em sistemas agroflorestais no Sul do Brasil têm mostrado o potencial do sombreamento parcial no manejo desta cultura. O objectivo deste trabalho foi avaliar as condições do microclima e seus efeitos na produção de café sombreado com guandu (Cajanus cajan), em comparação ao cultivado a pleno sol, no período de maio de 2001 a agosto de 2002 em Londrina, PR. As características microclimáticas avaliadas foram: radiação global, fotossintética e saldo de radiação; temperaturas do ar, da folha e do solo; e umidade do solo. O sombreamento causou significativa redução na radiação solar global incidente, na radiação fotossinteticamente ativa e na radiação líquida, e atenuou as temperaturas máximas foliar, do ar e do solo, durante o dia. O sombreamento também evitou o declínio acentuado, durante a noite, das temperaturas do ar e da folha, especialmente durante noites com geadas de radiação. Os valores de umidade do solo, na camada 0-10 cm de profundidade, foram maiores nos cafeeiros sombreados. As plantas sombreadas produzem frutos maiores em virtude da maturação mais lenta, entretanto, emitem menos ramos plagiotrópicos, com menor número de nós por ramo e poucos nós com frutos, o que resulta na redução da produção de café. Estes resultados evidenciam a necessidade de se definir uma densidade ótima de sombreamento, que não comprometa a produção e proteja contra as temperaturas extremas