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1.
Land converted to coffee agriculture occupies >5 million hectares of what was once prime overwintering natural habitat in the American Neotropics for migrating birds. When tree canopy is retained or restored (i.e., shade‐grown), coffee farms can serve as habitat refuge for wildlife. Yet few studies have examined whether canopy tree identity impacts habitat quality for biodiversity. Specifically, whether or not certain tree species are disproportionately important for foraging insectivorous birds remains unclear. In this study, we quantified bird foraging activity on 22 tree species in two Latin American Bird Friendly© coffee farms. Specifically, we conducted timed observations on focal trees to determine 1) tree preferences, 2) foraging bird abundance, 3) foraging time, and 4) species richness of birds using each canopy tree species. We found that birds did not forage randomly, and instead exhibited preferences for particular native tree species. Nitrogen‐fixing Fabaceae were consistently used more frequently, supported more resident and migratory birds for longer periods of time, and supported more bird species than trees in other families. We posit that the potential mechanism contributing to tree preferences is the increase in insect abundance and diversity that provide high‐quality food for insectivores but do not present pest problems for coffee. Thus, tree species that support insects may provide multiple benefits for farmers in the form of bottom‐up soil fertilization and top‐down pest control. This study provides evidence that agroforestry land can be improved for birds of conservation concern by prioritizing canopy tree species that help birds and farm productivity.  相似文献   

2.
It has been suggested that biodiversity in agroecosystems depends on both landscape heterogeneity and farm management, but at the same time, studies of biodiversity in relation to both landscape variables and farm management are rare. We investigated the species richness of plants, butterflies, carabids, rove beetles and the diversity of spiders in cereal fields, leys (grass and clover crop) and semi-natural pastures at 16 farms in Central East Sweden. The farms were divided into eight pairs of one conventional and one organic farm to enable us to separate the effects of landscape and farm management on biodiversity. The pairing was based on land use, location, and landscape features. Species richness of different taxonomic groups was generally not correlated. There were no differences in species richness between the farming systems, except for carabids that had higher numbers of species on conventional farms. The species richness generally increased with landscape heterogeneity on a farm scale. Habitat type had a major effect on the species richness for most groups, with most species found in pastures and leys. The correlations between species richness and landscape variables on a farm scale, and not on a scale of multiple farms, identify farmers as the important decision-maker in conservation issues for these taxonomic groups. We discuss the role of species richness of pests' natural enemies for biological control and conservation strategies of the more common species in the agricultural landscape.  相似文献   

3.
As large nature reserves occupy only a fraction of the earth’s land surface, conservation biologists are critically examining the role of private lands, habitat fragments, and plantations for conservation. This study in a biodiversity hotspot and endemic bird area, the Western Ghats mountains of India, examined the effects of habitat structure, floristics, and adjacent habitats on bird communities in shade-coffee and cardamom plantations and tropical rainforest fragments. Habitat and birds were sampled in 13 sites: six fragments (three relatively isolated and three with canopy connectivity with adjoining shade-coffee plantations and forests), six plantations differing in canopy tree species composition (five coffee and one cardamom), and one undisturbed primary rainforest control site in the Anamalai hills. Around 3300 detections of 6000 individual birds belonging to 106 species were obtained. The coffee plantations were poorer than rainforest in rainforest bird species, particularly endemic species, but the rustic cardamom plantation with diverse, native rainforest shade trees, had bird species richness and abundance comparable to primary rainforest. Plantations and fragments that adjoined habitats providing greater tree canopy connectivity supported more rainforest and fewer open-forest bird species and individuals than sites that lacked such connectivity. These effects were mediated by strong positive effects of vegetation structure, particularly woody plant variables, cane, and bamboo, on bird community structure. Bird community composition was however positively correlated only to floristic (tree species) composition of sites. The maintenance or restoration of habitat structure and (shade) tree species composition in shade-coffee and cardamom plantations and rainforest fragments can aid in rainforest bird conservation in the regional landscape.  相似文献   

4.
1 In Mesoamerica, shade trees are often included within coffee (Coffea arabica) agroforestry systems. Shade trees potentially protect the main crop by increasing vegetational diversity and reducing insect herbivory through one or more mechanisms. 2 The effect of on‐farm vegetational diversity on harvesting of coffee leaves by the leaf‐cutting ant, Atta cephalotes L., was examined on 15 coffee farms varying in vegetational diversity near Turrialba, Costa Rica. The farms ranged from coffee monocultures to complex‐shade coffee systems with three or more tree species present. The vegetational diversity of each farm was quantified using a leaf area index. 3 The species composition and biomass of the plant material being carried into colonies by ants was collected, identified to species, and its biomass was quantified four times during one year for at least two colonies in each of the 15 farms. 4 The proportion of plant biomass that was coffee being retrieved by A. cephalotes differed significantly among farm management types, and was highest (40%) in monocultures and lowest (< 1%) in farms with complex shade. Coffee was always harvested in a lower proportion than predicted based upon its relative abundance on the farms. 5 In dual‐choice bioassays with laboratory colonies, A. cephalotes significantly preferred the leaves of the predominant shade tree species on the farms, poró (Erythrina poeppigiana) over coffee. 6 The results indicate risk of injury by A. cephalotes can be reduced in vegetationally diverse coffee agroecosystems due at least in part to a foraging preference by the ants for plants other than coffee.  相似文献   

5.
The coffee (Coffea arabica) agro-ecosystem in the Central Valley of Costa Rica was formerly characterized by a high vegetational diversity. This complex system has been undergoing a major transformation to capital-intensive monocultural plantations where all shade trees are eliminated. In this study we examined the pattern of arthropod biodiversity loss associated with this transformation. Canopy arthropods were sampled in three coffee farms: a traditional plantation with many species of shade trees, a moderately shaded plantation with only Erythrina poeppigeana and coffee, and a coffee monoculture. An insecticidal fogging technique was used to sample both canopy and coffee arthropods. Data are presented on three major taxonomic groups: Coleoptera, non-formicid Hymenoptera, and Formicidae. Data demonstrate that the transformation of the coffee agro-ecosystem results in a significant loss of biological diversity of both canopy arthropods as well as arthropods living in coffee bushes. Percentage of species overlap was very small for all comparisons. Furthermore, species' richness on a per tree basis was found to be within the same order of magnitude as that reported for trees in tropical forests. If results presented here are generalizable, this means that conservation efforts to preserve biological diversity should also include traditional agro-ecosystems as conservation units.  相似文献   

6.
The ongoing destruction of tropical rainforests has increased the interest in the potential value of tropical agroforests for the conservation of biodiversity. Traditional, shaded agroforests may support high levels of biodiversity, for some groups even approaching that of undisturbed tropical forests. However, it is unclear to what extent forest fauna is represented in this diversity and how management affects forest fauna in agroforests. We studied lower canopy ant and beetle fauna in cacao agroforests and forests in Central Sulawesi, Indonesia, a region dominated by cacao agroforestry. We compared ant and beetle species richness and composition in forests and cacao agroforests and studied the impact of two aspects of management intensification (the decrease in shade tree diversity and in shade canopy cover) on ant and beetle diversity. The agroforests had three types of shade that represented a decrease in tree diversity (high, intermediate and low diversity). Species richness of ants and beetles in the canopies of the cacao trees was similar to that found in lower canopy forest trees. However, the composition of ant and beetle communities differed greatly between the agroforest and forest sites. Forest beetles suffered profoundly from the conversion to agroforests: only 12.5% of the beetle species recorded in the forest sites were also found in the agroforests and those species made up only 5% of all beetles collected from cacao. In contrast, forest ants were well represented in agroforests, with 75% of all species encountered in the forest sites also occurring on cacao. The reduction of shade tree diversity had no negative effect on ants and beetles on cacao trees. Beetle abundances and non-forest ant species richness even increased with decreasing shade tree diversity. Thinning of the shade canopy was related to a decrease in richness of forest ant species on cacao trees but not of beetles. The contrasting responses of ants and beetles to shade tree management emphasize that conservation plans that focus on one taxonomic group may not work for others. Overall ant and beetle diversity can remain high in shaded agroforests but the conservation of forest ants and beetles in particular depends primarily on the protection of natural forests, which for forest ants can be complemented by the conservation of adjacent shaded cacao agroforests.  相似文献   

7.
8.
Coffee agroforests may be structurally and floristically complex and may contain a significant fraction of species from biodiverse and threatened tropical montane forest biotas; hence, understanding the dynamics of tropical forest biodiversity in coffee agroecosystems has emerged as a centrally important area of tropical conservation biology research. We conducted a morphospecies analysis on foliage-dwelling beetles collected from coffee plants on four coffee farms in southern Chiapas, Mexico, to characterize variation in the abundance, species richness, and species composition of this mega-diverse taxon in relation to coffee cultivation system, spatio-temporal variation, and predator removal. We constructed thirty-two cages to exclude birds and bats on four farms, each enclosing 7–10 coffee plants and paired with an adjacent uncaged control plot, and then collected beetles from coffee foliage with D-Vac aspirators in each plot once every 3 months for one year.We classified the 2662 beetles collected into 293 morphospecies, representing 42 families of beetles. Extrapolation and interpolation analyses revealed a very high level of species richness, with no plateau and only a slight leveling trend observed in our species accumulation curves. We found that low-shade systems contain equal or higher beetle abundance, lower species richness, more highly homogenized species composition, and higher abundance of coffee berry borer pests on coffee foliage than do high-shade systems. We observed no effect of flying vertebrate exclusion on the coffee foliage beetle assemblage, but did find significant variation in abundance, species richness, and species composition of coffee foliage beetles across seasons and study sites.The increased beetle biodiversity of high-shade coffee cultivation systems has important implications both for the preservation of native biodiversity in coffee growing regions and for the control of agricultural pests such as the coffee berry borer.  相似文献   

9.
Coffee agroforestry systems (CAFS) are often considered to be species-rich, potentially contributing to the conservation of indigenous trees. To investigate the conservation capacity of a Kenyan CAFS, all tree species on 62 smallholder coffee farms (covering 39 ha in total) in the Aberdare Mountains of Central Kenya were recorded. In total, 6,642 trees of 59 species were enumerated, with a mean density of 256 trees per ha and a mean species richness of 11.2 species per farm. Indigenous species represented 63 % of the richness but only 31 % of the abundance. For individual farms, as expected, farm size had a positive correlation with tree species richness, but more interestingly there was a negative correlation with tree density. Cluster analysis based on densities of the 18 most important species (defined by an importance value index) revealed two groups of farms: one cluster represented small farms (mean size = 0.4 ha) with high tree species diversity and individual density, particularly of indigenous trees; the other cluster represented large (mean size = 1 ha) and less diverse farms with low tree densities, particularly regarding indigenous species. Tree individuals were unevenly distributed within farms, being more frequent in living fences (38 % of all individuals), the garden zone (20 %) and in coffee plots (18 %). The relative occurrence of indigenous species was also uneven, being greater in living fences and the garden zone. Most adult trees (83 %) were planted, but only 46 % of seedlings were, revealing the active removal of volunteer seedlings by farmers as trees mature. Surveyed coffee farms harboured 20 % of the 135 tree species of the potential natural vegetation for the region, but only 3.6 % of the on-farm tree individuals belonged to the most valuable types of dominant and forest vegetation. Thus, although a source of significant tree cover and heterogeneity at landscape level, the value of these CAFS as circa situm reservoirs of forest tree species is questionable.  相似文献   

10.
Agriculture of varying management intensity dominates fragmented tropical areas and differentially impacts organisms across and within taxa. We examined impacts of local and landscape characteristics on four groups of ants in an agricultural landscape in Chiapas, Mexico comprised of forest fragments and coffee agroecosystems varying in habitat quality. We sampled ground ants found in leaf litter and rotten logs and arboreal ants found in hollow coffee twigs and on tree trunks. Then using vegetation and agrochemical indices and conditional inference trees, we examined the relative importance of local (e.g. vegetation, elevation, agrochemical) and landscape variables (e.g. distance to and amount of nearby forest and rustic coffee) for predicting richness and abundance of ants. Leaf litter ant abundance increased with vegetation complexity; richness and abundance of ants from rotten logs, twig-nests, and tree trunks were not affected by vegetation complexity. Agrochemical use did not affect species richness or abundance of any ant group. Several local factors (including humus mass, degree of decay of logs, number of hollow twigs, tree circumference, and absence of fertilizers) were significant positive predictors of abundance and richness of some ant groups. Two landscape factors (forest within 200 m, and distance from forest) predicted richness and abundance of twig-nesting and leaf litter ants. Thus, different ant groups were influenced by different characteristics of agricultural landscapes, but all responded primarily to local characteristics. Given that ants provide ecosystem services (e.g. pest control) in coffee farms, understanding ant responses to local and landscape characteristics will likely inform farm management decisions.  相似文献   

11.
Small coffee farms around Mount Kenya in Kenya contain many planted and remnant tree species but little is known in the region about the relationship between trees on farms and the methods and dynamics of coffee production. Shifts in production may alter tree diversity and potentially impact on future biodiversity conservation efforts by affecting niches available for indigenous trees on farms. Here, knowledge was gathered on how changes in coffee production on 180 small farms around Mount Kenya may affect tree diversity, categorizing farms according to coffee yield levels over a period of five years as increasing, decreasing or stable production. Tree species richness, abundance and composition were analyzed using species accumulation curves, Rènyi diversity profiles, rank abundance and ecological distance ordinations, and the effects of coffee production examined using quasi-Poisson generalized linear regressions. Species richness were positively correlated with tree basal area but negatively related to coffee, banana and maize yields value. A difference in average tree species richness, abundance and basal area on increasing farms was observed compared to the decreasing and stable farms, even though formal tests on richness and densities differences were inconclusive. These dynamics do not significantly influence vegetation structure but seem to have a bearing on species composition on farms of different coffee production. The overall low abundance (23 % of trees) but high richness (78 % of species) of indigenous trees on coffee farms could change markedly if the dynamics observed in the current study persist, indicating the need for the development of intensified multi-species cropping systems.  相似文献   

12.
The Kingdom of Nepal extends 800 km east to west along the southern slopes of the Himalayas. Because of its biogeographical position, Nepal contains biological elements of both the Indo-Malayan and Palaearctic realms. Beside the trees in forest ecosystems, a large number of tree species are maintained on farms as part of subsistence farming systems. The role of these trees in ensuring the sustainability of agricultural production and the importance of traditional farming systems for the conservation of crop diversity have been well documented. However, the status of farm trees and their role in biodiversity conservation are poorly documented. This paper presents a case study of two villages in the western middle hills of Nepal. It highlights the role of traditional agroforestry practices for the conservation of tree diversity and argues that farms can be considered biodiversity reservoirs. Farm trees help to reduce pressure on community and government forests and create a favorable environment for many plant and animal species. Farm trees also provide social functions in that households with many farm trees no longer exercise their communal rights to extract grass products from community forests, which in turn benefits poor and disadvantaged households. The paper discusses possibilities to improve the role of farm trees in biodiversity conservation. It argues for the development of mechanisms such as tax exemptions and conservation credits that provide benefits to rural communities as compensation for their local and global environmental services including biodiversity conservation.  相似文献   

13.
Perfecto  I.  Vandermeer  J. 《Oecologia》1996,108(3):577-582
Recent changes in the coffee agroecosystem of Costa Rica were used to study the mechanism of biodiversity loss in transforming agroecosystems, focusing on the ground-foraging ant community. Coffee farms are being transformed from vegetationally diverse shaded agroforestry systems to unshaded coffee monocultures. We tested the hypothesis that the high-light environment and lack of leaf litter cover in the unshaded system are the determinants of the differences in ground-foraging ant diversity. Four treatments were established within the light gaps of a shaded plantation: shade, leaf litter, shade plus leaf litter, and a control (no shade or leaf litter added). Ants were sampled using tuna fish baits and light and temperature were measured. Shade and leaf litter had a significant effect on the ant fauna but probably for indirect reasons having to do with species interactions. In both shade treatments, Solenopsis geminata, the tropical fire ant, decreased significantly while the other species increased. The possibility that the physical factor changes the nature of competitive interactions between the most abundant species is discussed.  相似文献   

14.
Although it is clear that the farmlands neighbouring fragmented forests are utilized by some forest birds, it is not clear how birds in general respond to farmland habitat mosaic. An effort was made to determine how bird density and foraging assemblages were influenced by farm structural characteristics and distance from forest edge. Thirty farms up to a distance of 12 km around Kakamega forest in western Kenya were studied. Farm structure entailed size, hedge volume, habitat heterogeneity, woody plant density, plant diversity and crop cover. Birds were surveyed using line transects and DISTANCE analyses and classified into six feeding guilds and three habitat associations. Size of farms increased away from the forest, as woody plant density, plant diversity, indigenous trees and subsistence crop cover declined. The most important farm structure variable was hedge volume, which enhanced bird species richness, richness of shrub‐land bird species and insectivorous bird density (R = 0.58, P < 0.01). Bird density increased with tree density while indigenous trees were suitable for insectivores and nectarivores. There were very few forest bird encounters. Agricultural practices incorporating maintenance of hedges and sound selection of agroforestry trees can enhance conservation of birds on farmland, though, not significantly for forest species.  相似文献   

15.
Shaded coffee agroecosystems traditionally have few pest problems potentially due to higher abundance and diversity of predators of herbivores. However, with coffee intensification (e.g., shade tree removal or pruning), some pest problems increase. For example, coffee leaf miner outbreaks have been linked to more intensive management and increased use of agrochemicals. Parasitic wasps control the coffee leaf miner, but few studies have examined the role of predators, such as ants, that are abundant and diverse in coffee plantations. Here, we examine linkages between arboreal ant communities and coffee leaf miner incidence in a coffee plantation in Mexico. We examined relationships between incidence and severity of leaf miner attack and: (1) variation in canopy cover, tree density, tree diversity, and relative abundance of Inga spp. shade trees; (2) presence of Azteca instabilis, an arboreal canopy dominant ant; and (3) the number of arboreal twig‐nesting ant species and nests in coffee plants. Differences in vegetation characteristics in study plots did not correlate with leaf miner damage perhaps because environmental factors act on pest populations at a larger spatial scale. Further, presence of A. instabilis did not influence presence or severity of leaf miner damage. The proportion of leaves with leaf miner damage was significantly lower where abundance of twig‐nesting ants was higher but not where twig‐nesting ant richness was higher. These results indicate that abundance of twig‐nesting ants in shaded coffee plantations may contribute to maintenance of low leaf miner populations and that ants provide important ecosystem services in coffee agroecosystems.  相似文献   

16.
The occurrence, intensity, and composition of mutualisms are dependent not only on the co-occurrence of mutualists, but also the broader biotic context in which they are embedded. Here, the influence of the specific nest tree identity of the ant Azteca instabilis (F. Smith) on the density of the green coffee scale (Coccus viridis Green) was studied in a coffee agroecosystem in southern Mexico. The hypothesis that an indirect competitive interaction for ant attendance occurs between a scale species (Octolecanium sp. Kondo) in the canopy of the shade tree Inga micheliana Harms and C. viridis, which inhabits coffee bushes (Coffea arabica) beneath the shade trees was tested. Coffee bushes beneath a different shade tree species (Alchornea latifolia Swartz) were used as an indication of C. viridis density in a noncompetitive environment. Results indicate that C. viridis occurs in significantly lower density adjacent to nests in Inga, supporting the hypothesis of indirect competition. Additional experimentation suggests that there is a mutualism between Azteca and Octolecanium and that this interaction may be mediated by a hierarchy in ant attendance of scale insects. Our results show the importance of considering the biotic context of ant-hemipteran mutualisms. In coffee agroecosystems, consideration of shade tree diversity and species composition may be directly applicable to the biological control of insect pests.  相似文献   

17.
Theobroma cacao plantings, when managed under the shade of rainforest trees, provide habitat for many resident and migratory bird species. We compared the bird diversity and community structure in organic cacao farms and nearby forest fragments throughout mainland Bocas del Toro, Panama. We used this dataset to ask the following questions: (1) How do bird communities using cacao habitat compare to communities of nearby forest fragments? (2) To what extent do Northern migratory birds use shaded cacao farms, and do communities of resident birds shift their abundances in cacao farms seasonally? (3) Do small scale changes in shade management of cacao farms affect bird diversity? Using fixed radius point counts and additional observations, we recorded 234 landbird species, with 102 species that were observed in both cacao and forest fragments, 86 species that were only observed in cacao farms, and 46 species that were restricted to forest fragments. Cacao farms were rich in canopy and edge species such as tanagers, flycatchers and migratory warblers, but understory insectivores were nearly absent from cacao farms. We observed 27 migratory species, with 18 species in cacao farms only, two species in forest only, and seven species that occurred in both habitats. In cacao farms, the diversity of birds was significantly greater where there was less intensive management of the canopy shade trees. Shade tree species richness was most important for explaining variance in bird diversity. Our study shows that shaded cacao farms in western Panama provide habitat for a wide variety of resident and migratory bird species. Considering current land use trends in the region, we suggest that action must be taken to prevent conversion away from shaded cacao farms to land uses with lower biodiversity conservation value.  相似文献   

18.
AimCoffee is an important export for many developing countries, with a global annual trade value of $100 billion, but it is threatened by a warming climate. Shade trees may mitigate the effects of climate change through temperature regulation that can aid in coffee growth, slow pest reproduction, and sustain avian insectivore diversity. The impact of shade on bird diversity and microclimate on coffee farms has been studied extensively in the Neotropics, but there is a dearth of research in the Paleotropics.LocationEast Africa.MethodsWe created current and future regional Maxent models for avian insectivores in East Africa using Worldclim temperature data and observations from the Global Biodiversity Information Database. We then adjusted current and future bioclimatic layers based on mean differences in temperature between shade and sun coffee farms and projected the models using these adjusted layers to predict the impact of shade tree removal on climatic suitability for avian insectivores.ResultsExisting Worldclim temperature layers more closely matched temperatures under shade trees than temperatures in the open. Removal of shade trees, through warmer temperatures alone, would result in reduction of avian insectivore species by over 25%, a loss equivalent to 50 years of climate change under the most optimistic emissions scenario. Under the most extreme climate scenario and removal of shade trees, insectivore richness is projected to decline from a mean of 38 to fewer than 8 avian insectivore species.Main conclusionsWe found that shade trees on coffee farms already provide important cooler microclimates for avian insectivores. Future temperatures will become a regionally limiting factor for bird distribution in East Africa, which could negatively impact control of coffee pests, but the effect of climate change can be potentially mediated through planting and maintaining shade trees on coffee farms.  相似文献   

19.
Coffee with diverse shade trees is recognized as conserving greater biodiversity than more intensive production methods. Sustainable certification has been proposed as an incentive to conserve shade grown coffee. With 40% of global coffee production certified as sustainable, evidence is needed to demonstrate whether certification supports the environmental benefits of shade coffee. Environmental and economic data were taken from 278 coffee farms in Nicaragua divided between non-certified and five different sustainable certifications. Farms were propensity-score matched by altitude, area of coffee and farmer education to ensure comparability between non-certified and certified farms. Farms under all certifications had better environmental characteristics than non-certified for some indicators, but none were better for all indicators. Certified farms generally received better prices than non-certified farms. Farms with different certifications had different investment strategies; C.A.F.E. Practice farms had high investment and high return strategies, while Utz and Organic farms had low investment, low productivity strategies. Tree diversity was inversely related to productivity, price and net revenue in general, but not for certified farms that received higher prices. Certification differentiates farms with better environmental characteristics and management, provides some economic benefits to most farmers, and may contribute to mitigating environment/economic trade-offs.  相似文献   

20.
Coffea arabica occurs naturally in the montane rainforests of Ethiopia, but large areas of these unique forests have been converted to other land-uses. In the remaining forest, wild coffee is managed and harvested with increasing intensity because of rising coffee prices in the world market. This study evaluated the impact of coffee management on wild coffee populations and the forest vegetation as a basis for conservation planning in southwestern Ethiopia. Vegetation surveys and yield assessments were carried out in unmanaged natural forest and in managed semi-forest coffee (SFC) systems. Analyses show that wild coffee density and coffee yields were low in natural forest (max. 15 kg ha−1 year−1). In SFC systems, 30% of the canopy trees and most undergrowth vegetation were removed. This stimulated wild coffee growth and strongly enhanced yields (max. 54 kg ha−1 year−1), but severely disturbed forest structure. Species richness increased by 26% because of an increase in species of ruderal and secondary vegetation; however, species richness and abundance of typical forest species declined. Conservation of the natural forest therefore requires the control of wild coffee management. Wild coffee certification is discussed as one tool to reconcile conservation measures and the interests of local farmers.  相似文献   

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