15 research outputs found
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Managing Oil Palm Plantations More Sustainably: Large-Scale Experiments Within the Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Programme
Conversion of tropical forest to agriculture results in reduced habitat heterogeneity, and associated declines in biodiversity and ecosystem functions. Management strategies to increase biodiversity in agricultural landscapes have therefore often focused on increasing habitat complexity; however, the large-scale, long-term ecological experiments that are needed to test the effects of these strategies are rare in tropical systems. Oil palm (Elaeis guineensis Jacq.)—one of the most widespread and important tropical crops—offers substantial potential for developing wildlife-friendly management strategies because of its long rotation cycles and tree-like structure. Although there is awareness of the need to increase sustainability, practical options for how best to manage oil palm plantations, for benefits to both the environment and crop productivity, have received little research attention. In this paper we introduce the Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Programme: a long-term research collaboration between academia and industry in Sumatra, Indonesia. The BEFTA Programme aims to better understand the oil palm agroecosystem and test sustainability strategies. We hypothesise that adjustments to oil palm management could increase structural complexity, stabilise microclimate, and reduce reliance on chemical inputs, thereby helping to improve levels of biodiversity and ecosystem functions. The Programme has established four major components: (1) assessing variability within the plantation under business-as-usual conditions; (2) the BEFTA Understory Vegetation Project, which tests the effects of varying herbicide regimes; (3) the Riparian Ecosystem Restoration in Tropical Agriculture (RERTA) Project, which tests strategies for restoring riparian habitat; and (4) support for additional collaborative projects within the Programme landscape. Across all projects, we are measuring environmental conditions, biodiversity, and ecosystem functions. We also measure oil palm yield and production costs, in order to assess whether suggested sustainability strategies are feasible from an agronomic perspective. Early results show that oil palm plantation habitat is more variable than might be expected from a monoculture crop, and that everyday vegetation management decisions have significant impacts on habitat structure. The BEFTA Programme highlights the value of large-scale collaborative projects for understanding tropical agricultural systems, and offers a highly valuable experimental set-up for improving our understanding of practices to manage oil palm more sustainably
Distributional Patterns of Epiphytic Ferns are Explained by the Presence of Cryptic Species
In a recent article in this journal Zhang and colleagues investigated the factors affecting the distribution of a species of epiphytic fern Asplenium nidus L. in rain forest in Peninsular Malaysia. Here we suggest that their findings may be interpreted in the light of there being two cryptic species present, each with different ecologies, as is the case in Malaysian Borneo. We also discuss the implications of the existence of cryptic species when attempting to conserve forest diversity in the face of climate change and habitat conversion.Abstract in Malay is available at http://www.blackwell-synergy.com/loi/btp. © 2010 The Author(s). Journal compilation © 2010 by The Association for Tropical Biology and Conservation
The Effect of Rain Forest Canopy Architecture on the Distribution of Epiphytic Ferns (Aspleniumspp.) in Sabah, Malaysia
Epiphytic plants are a dominant component of the rain forest canopy biota. They represent a significant proportion of canopy plant biomass and diversity, play a key role in nutrient cycling, and support highly abundant and diverse animal communities. Understanding the factors affecting their distribution in this three-dimensional habitat is consequently of great importance, not least because they may be particularly vulnerable to climate change and habitat conversion. Here we investigate how canopy architecture affects the distribution of two species of bird's nest fern (Asplenium spp.) in pristine rain forest. Both species were found at high abundances (Asplenium phyllitidis: 136ha, SE ± 31.6, Asplenium nidus: 44ha, SE ± 9.2) and their distributions were differentially affected by canopy architecture. Asplenium phyllitidis was found only at heights < 30 m in areas with a thicker lower canopy layer. Asplenium nidus was found at all heights in the canopy and was associated with emergent trees and areas with an open understory. Larger A. phyllitidis were found higher in the canopy while larger A. nidus were found on trunks and branches with a wider diameter. Asplenium nidus seems adapted to withstand the hot dry conditions in the upper canopy and in gaps, and its size is consequently limited only by the size of its support. Asplenium phyllitidis is dominant in areas that are cooler and damper, and so the growth rate of individuals may be limited by light levels. We discuss possible implications of this partitioning for epiphyte communities in the face of climate change and habitat conversion. in Malay is available at © 2009 The Association for Tropical Biology and Conservation
Public goods, public services and by-product mutualism in an ant-fern symbiosis
Mutualism can evolve when organisms make novel connections that happen to benefit all parties. When such connections involve a host that provides a public good for multiple visitor species, selection for reciprocal cooperation is only likely if the host has the power to preferentially increase the fitness of those visitors that provide a better quality service. In contrast, when interactions form between multiple visitors and a host that lacks the power to partition the public good, we predict that interactions are likely to persist only as by-product mutualisms, in which symbiosis benefits both host and visitor, but in which neither partner makes costly investments. Focusing on the symbiosis between ants and litter trapping epiphytes in the canopy of lowland dipterocarp rain forest in Borneo, we show that at least 71 ant species share the public good of housing within the root-mass of epiphytic bird's nest ferns (Asplenium spp.). Ferns supporting a higher biomass of ants experienced less herbivory, and experimental exclusions of ants from fronds confirmed that this is caused by the ants protecting the ferns from herbivores. These results establish that there are clear by-product benefits for both parties of housing for ants and protection for ferns. If these benefits were to drive selection for reciprocal cooperation, we would expect larger ferns to support ant colonies that were larger or colonies that produce more reproductive individuals. This was not the case. Larger ferns instead supported more ant colonies, indicating that the housing provided by the fern is a public good that is not restricted to better cooperating ant species. Mutualism via novel connections is thus unlikely to evolve between a host and multiple partners, even if there are clear by-product benefits to all parties, unless the host can direct benefits to cooperators. © 2011 The Authors. Oikos © 2011 Nordic Society Oikos
'Working with Allies: The United States, the United Kingdom, and the War on Terror'
This article considers the special case of the United States' relationship with Great Britain—America's closest ally—in the context of the post-9/11 debate over unilateralism and multilateralism. It explains the development of unilateral preferences in the post-Cold War order and, latterly, in the foreign policies of the George W. Bush Administration. The Bush Administration's outlook is seen as much more complex than many commentators assume, notwithstanding its acceptance of the logic of unilateralism and "coalitions of the willing" in pursuing the "War on Terror." The putative "specialness" of the U.S.–U.K. relationship is examined through a skeptical eye, from both the U.S. and British perspectives. Its contemporary manifestation is placed to a considerable degree by the personal leadership style and convictions of Prime Minister Tony Blair of Britain. In the final part of the article, the U.S.–U.K. alliance is assessed in light of the broader debate about America's need for allies in the new international order and its capacity to "work with allies" effectively