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Interest in the ecology and conservation of birds in coffee plantations around the world has greatly increased since the early 1990s, especially in the Neotropical region. Much of the interest was inspired by untested hypotheses proposing that extensive conversion of traditional coffee plantations, grown under a diverse canopy of shade trees, into modern, technified plantations with severely reduced shade canopy, contributed to concurrent declines of long-distance migratory birds. This possible relationship sparked major publicity campaigns during the late 1990s and continuing today, promoting shaded coffee plantations as quality habitat for migratory birds. Based on a review of the published scientific literature concerning avian use of coffee plantations, I summarize avian ecology in coffee agroecosystems, and evaluate the hypothesis that coffee plantations are important for the conservation of migratory or resident birds. While no literature has presented strong evidence that coffee plantations in general negatively affect bird populations of conservation importance, nonetheless published studies have not tested hypotheses that birds have greater survivability, fitness or productivity in coffee plantations compared with other available habitats (natural or artificial), or that any species selects coffee plantations over other available habitats for foraging or for breeding. While coffee plantations may have higher avian richness and abundance than other highly disturbed agricultural habitats and some natural habitats, more research is needed to evaluate whether and how certain coffee agroecosystems contribute to the conservation or decline of avian diversity.
Monoculture plantations of exotic Caribbean pine Pinus caribaea have been planted extensively in many tropical countries, but little is known about the bird communities inhabiting them. From October 1995 to September 1996, we compared bird populations in a 37-ha stand of mature Caribbean pine forest (planted in 1972) with an adjacent, similar-sized stand of native broad-leaved forest at Mount Saint Benedict, Trinidad, West Indies. Ten censuses, each including 10 fixed-radius point counts (25 m radius, 10 minutes duration), were conducted simultaneously during different months of the year in each habitat. Both species richness and species diversity were significantly lower in the pine forest, but the overall abundance of individual birds did not differ between the two forests. Seasonal variation in bird populations was more pronounced in the pine forest, where fewer birds (and presumably food resources) were present during the dry season. The pine forest bird community was dominated by forest edge specialists and the native forest by forest interior specialists at both the individual and species levels. At the individual level, nectarivores, aerial foragers and understorey foragers were proportionately more common in the pine forest; insectivores and canopy foragers were more common in the native forest. At the species level, more aerial foragers occurred in the pine forest and more understorey foragers in the native forest. The diversity of bird communities in pine plantations may be promoted by increasing habitat heterogeneity.
Agricultural intensification in shade coffee farms has strong impacts on the structure and diversity of the agroforest, with negative consequences for forest specialist birds, understorey insectivores and their associated ecosystem services. Utilising variable distance transect counts, we sampled the bird community in a multiple-certified yet changing shade coffee landscape in the Peruvian East Andean foothills, to evaluate bird functional diversity and to assess potential impacts of coffee production on avian ecosystem services. To account for incomplete detection, we also calculated expected species richness per functional group, and to evaluate the effect of future species losses, we derived reduced bird communities by subsampling our data using a Monte Carlo procedure. We compared the relative abundances of functional groups based on preferred diets in the observed, expected and reduced bird communities to global functional signatures of tropical bird assemblages of forest, agroforests and agriculture. The birds in the shade coffee landscape were predominantly birds of secondary and disturbed forest habitats, indicating, as expected, strong human impact on the forest structure. Yet, the diet signatures of the observed, expected and simulated bird communities were not significantly different from global diet signatures of forest and agroforest bird communities of mixed tropical landscapes. Our results suggest that avian ecological function can be conserved at bird community level despite intensive human ecosystem use and associated losses of forest specialist and other less resilient bird species. These results underscore that forest management strategies or certification audits focused solely at ecosystem services may be insufficient to support conservation of rare or threatened bird species and that shade coffee systems can in no way replace the role of protected natural forests.
This paper describes changes in bird communities following the conversion of lowland forest to commercial oil palm and rubber plantations. Conversion of forest to plantations resulted in a reduction in species richness of at least 60%, with insectivores and frugivores suffering greater losses than more omnivorous species. Of the 128 species recorded across all habitats, 84% were recorded in forest, and 60% were recorded only in that habitat. Of the 16 Globally Threatened or Near-Threatened species recorded in the study, 15 were recorded only in forest. Species occurring in plantations were significantly more widespread in Thailand than species recorded only in forests and had a tendency towards smaller body size. Species richness in plantations was unaffected by plantation age or distance from nearest forest edge, but was significantly greater where undergrowth was allowed to regenerate beneath the crop trees. Bird communities in oil palm and rubber plantations were extremely similar, and there was a strong positive correlation across species in their relative abundance in each plantation type. The results indicate that a high proportion of species formerly present in the region are unable to adapt to conversion of forest to oil palm and rubber plantations, resulting in large losses of bird species and family richness and the replacement of species with restricted ranges and high conservation status by those with extensive ranges and low conservation status. Initiatives that reduce pressure to clear new land for plantations, for example by increasing productivity in existing plantations and improving protected area networks, are likely to be more effective in conserving threatened forest birds than initiatives to improve conditions within plantations, though both should be encouraged.
Tropical land cover change has negatively affected numerous migratory bird populations. Forest restoration can augment migrant wintering habitat. However, almost no information exists about factors that influence migrant use of tropical restoration sites. We sampled migrant birds in young restoration sites in Costa Rica from February 2006 to April 2008 to determine how vegetation height, planting design, season, and landscape forest cover influenced capture rates of four declining species. We also documented total numbers of migratory species and individuals captured in each planting design treatment; each site had a control treatment where seedlings were not planted, an island treatment where seedlings were planted in patches, and a plantation treatment where seedlings were planted to cover the entire area. Sites varied in landscape forest cover within 500 m buffers. Three out of four focal species were captured significantly more often in plantation treatments than island or control treatments. Two of the four species showed seasonal patterns and one species was captured more often in high-vegetation sites. Greater numbers of species and individuals were captured in plantation treatments compared to island and control treatments. The plantation planting design increased migrant use more quickly than the island planting design. When resources are available, we recommend planting plantation-style to rapidly increase the value of restoration sites to a range of species, particularly those that use woody vegetation. When resources are more limited, planting islands may be a cost-effective, although not as ecologically effective, alternative that supports a diversity of migrant species compared to unplanted controls.
The Congo Grey Parrot Psittacus erithacus has experienced a severe population breakdown in recent decades. The rainforests of the Korup region in Southwest Cameroon may harbour a large population of this species, but density and population estimates from this area remain controversial. Before the 2016 breeding season, we surveyed Grey Parrots along transects (621.1 km survey effort) in three adjacent landscape types: primary forest in Korup National Park (KNP), smallholder agroforestry matrix (AFM), and industrial oil palm plantation (OPP). We also collected information on the trees used for nesting, feeding and roosting. Using Distance analysis, we estimated relatively low densities of stationary flocks, ranging from 0.30 ind./km2 in KNP, over 0.82 ind./km2 in OPP to 2.70 ind./km2 in the AFM. Parrots were observed feeding or roosting in 17 tree species, of which 15 were located in AFM alone. Feeding was most often observed on cultivated Elaeis guineensis and Dacryodes edulis, but never in maize. The detected parrot densities probably reflect declines within the period 2008–2016, suggesting that the species’ recent IUCN uplisting to ‘Endangered’ and transfer to CITES Appendix I was indeed justified. Our results also suggest that traditional smallholder agroforestry may play a role in habitat conservation strategies, since these forms of cultivation may maintain important breeding and feeding opportunities for Congo Grey Parrots.
Decline of native forest cover is a worldwide concern. Recently, overall forest cover in Vietnam has increased, but most of the increase has been attributed to plantations of non-native trees. The conservation value of these plantations for birds is unknown. We compared avian species richness in pine plantations to that in second-growth and mature native forests in Tam Dao National Park, Vietnam. Bird species were classified into two categories: forest specialists or forest generalists. To account for strong heterogeneity in detection probabilities, the number of species in each category was estimated using the Pledger-Huggins estimator. We estimated total species richness and number of forest specialist species to be highest in mature forest (191; 95% CI = 96, 287, and 88; 95% CI = 47, 129 respectively), lower in second-growth forest (158; 95% CI = 87, 245 and 58; 95% CI = 18, 98 respectively), and lowest in pine plantation (106; 95% CI = 52, 158 and 49; 95% CI = 2, 97 respectively). The estimated number of forest generalist species was similar between mature forest and second-growth forest (103; 95% CI = 17, 189 and 100; 95% CI = 42, 158, respectively) and least in pine plantation (57; 95% CI = 31, 82). The maintenance of native forest types should receive priority for conservation in Vietnam and pine plantations should be managed to provide additional structure in the hope of increasing species richness.
Growing Points in Neotropical Migratory Bird Conservation
Habitats at intermediate and upper elevations of the volcanic Cordillera of southwestern Guatemala harbour a diverse terrestrial vertebrate fauna that includes at least 423 avian species, 108 of which are known to be Nearctic migrants, and 43 of which are known or suspected to have both resident and long-distance migrant populations. During the course of floral and faunal inventories in a proposed Multiple Use Area in this region from 1987 through 1991, FIIT researchers collected or observed 254 avian species, of which 44 are regarded as Nearctic migrants and 26 are known or suspected to have both resident and long-distance migrant populations. Study sites included climax and selectively logged lower montane forest fragments, as well as subtropical agroecosystems. Data are presented to support the conclusion that a significantly higher percentage of resident avian species reported from this region in the literature continue to occupy these habitats than do species known to undertake cyclical longdistance migrations. Non-quantitative, historical reports of relative abundance of all Nearctic avian migrants in the region during the early and mid-twentieth century are compared with current status of these species. Threats to Nearctic avian migrants in the western Guatemalan highlands are discussed, and areas of future research for ornithologists working with this community in the region are proposed. Recommendations are made to preserve or improve habitats on wintering grounds and along migration routes considered to be of critical importance for the long-term survival of a number of threatened and vulnerable Nearctic avian migrants in Guatemala.
The Canada Warbler Cardellina canadensis is a steeply declining Neotropical migratory bird and > 50% of its non-breeding range is within the Colombian Andes. Despite being an abundant migrant in Andean forests, the species’ elevational distribution and non-breeding ecology have yet to be studied, thereby precluding the design of effective conservation actions. During four non-breeding periods (2012–2016), we surveyed Colombia’s three Andean ranges, carrying out passive 5-minute point counts between 700 and 3,150 m asl in five habitats (mature forest, secondary growth, forest edges/riparian forest, shade coffee, sun coffee), recording the perpendicular distance, sex, foraging height, and association with mixed species flocks of Canada Warbler. Habitat variables were recorded at each point. Based on 819 passive point counts, Canada Warblers occupied elevations between 750 and 2,300 m, being more abundant between 1,000 and 2,200 m. Relative densities were higher in mature forest compared to shade coffee and secondary forest, and accordingly abundance increased with canopy height. There was no evidence for a difference in elevation or habitat use by males and females. Within forests, birds foraged at mid-levels, 5–15 m above the ground, and the probability of Canada Warblers occurring in mixed species flocks increased with elevation. Models of variation in relative density throughout the Eastern Andes showed a positive relation with cloud cover and above-ground forest biomass, implying a preference for humid, forested regions. Of the areas in the Eastern Andes with high predicted relative density, ∼ 14% overlapped with protected areas and we identify priority areas where protective measures could benefit the conservation status of the species. For maximum effectiveness, conservation actions should focus on protecting forest fragments and initiating reforestation projects at mid-elevations (1,000–2,200 m), as well as supporting agroforestry practices in humid regions of the Colombian Andes.
Swainson’s Warbler Limnothlypis swainsonii is a secretive species of high conservation concern with an estimated global breeding population of 90,000 individuals sparsely distributed across 15 states in the south-eastern United States. Its status as one of the rarest songbirds in North America has been attributed to the scarcity of breeding and wintering habitat. Although the warbler was once thought to be a habitat specialist of lowland canebrakes, it is now known to breed in a wide spectrum of broadleaf forest habitats linked by the common denominator of high stem densities and visual screening in the understorey stratum. Scattered instances of a fundamental habitat expansion into early seral stages of even-aged pine plantations were first observed in east Texas in 1992. Here I report that the colonisation of pine plantations is not only locally extensive in Texas but that it is widespread on the coastal plain eastward to south-eastern Virginia. During two decades of field surveys, breeding territories (n = 297) were documented in young pine plantations in 95 counties and parishes in 10 states. Occupied plantations were mostly 6–12 m tall (median = 7.5 m), corresponding to 8–15 years after planting. Soil type and the presence of interspersed broadleaf vegetation may be important co-factors in plantation occupancy. The chronology of this breeding niche expansion is poorly known but it appears to have occurred after the 1970s, most likely catalysed by the rapid growth of pine plantation silviculture after World War II. As late as 2001, it was believed that > 90% of the breeding population occurred in broadleaf floodplain forest. The recent range-wide colonisation of pine plantations changes the calculus. If the current trend continues, forest lands managed for short-rotation pine plantations will support the majority of breeding populations by the end of the 21st century.
The exceptionally rapid degradation and fragmentation of the Upper Guinea Forest, caused by slash-and-burn farming and selective logging, oblige bird conservationists to examine critically the conservation value of unprotected areas, which may provide buffer zones or connecting corridors to protected forests. This paper assesses the utilisation of various tree-crop plantations by mainly lower storey forest birds in south-west Ghana, through avifaunal comparisons of shaded cash crops (rustic cocoa; neglected coconut) and exotic tree plantations (Cedrela, Gmelina) with nearby closed forest. Plantations adjacent to, or within, large (>200 km2), biodiverse forests are superior bird habitats compared to similar plantations within small (<50 km2) and species-poor forests. A relatively high forest tree density in cash crop (15–20 ha−1) and exotic (15–35 ha−1) tree plantations, combined with a luxuriant woody undergrowth (not slashed for >5–10 years), may additionally explain the presence of many forest specialists, including regionally ‘Vulnerable’ and locally ‘Endangered’ species. Overall, 50% of species of conservation importance found in forests were represented in plantations. These findings highlight the importance of shaded plantations with long periods between understorey weeding, as appropriate land-use systems that enhance the area under effective conservation and improve the connectivity of protected forest fragments. Results are compared to similar studies in the Old and New World tropics, and implications for off-reserve land-use management are compared and discussed in regional and global contexts.
Many studies have examined differences in bird communities between shade and sun coffee plantations but less is known about how different management practices within shade coffee plantations affect bird populations. This study compares diversity and abundance of resident and migrant birds in two shade coffee plantations located in Palajunoj, Quetzaltenango, Guatemala, that differ in their farming practices (e.g. pruning schedules and fertilizer regimes) and, consequently, in vegetation structure. One plantation represents a traditional, polyculture shade system whereas the second represents a more modernized, monoculture shade system. Both plantations supported many resident and migrant birds. Bird abundance and diversity were significantly greater during both wet and dry seasons on the traditional farm, due largely to the vegetation structure resulting from the different management practices. All plantations typically classified as ‘shade coffee’ are not equivalent, much of their conservation value coming from the more diverse and structurally complex traditional polycultures rather than from the newer, monocultural systems. Coffee production techniques that affect the structural and floristic diversity of the vegetation (e.g. pruning, application of chemicals) have important consequences for birds.
Forest ecosystems in South Africa are at risk from a variety of anthropogenic threats impacting the faunal species dependent on them. These impacts often differ depending on species-specific characteristics. Range data on forest dependent bird species from the South African Bird Atlas Project (SABAP1 and SABAP2) were analysed to determine links between deforestation, species characteristics and range declines. Half of the species studied were found to have declining ranges. Range change data for these species were correlated with data on changes in land cover from 1990 to 2014. To determine which land cover changes affect extinction, occupancy was modelled for 30 sites across South Africa which experienced a loss of more than 10 species. Most species lost were birds of prey or insectivores. Indigenous forest decreased in 17% (n = 5) sites, while plantations/woodlots decreased in 60% (n = 18) sites. Occupancy modelling showed extinction to be mitigated by plantations in 6/28 species, and forest expansion mitigated extinction in 7/28 species. Responses to deforestation did not appear to be related to particular species characteristics. Half of South Africa’s forest-dependent bird species have declining ranges, with the loss of these species most prominent in the Eastern Cape province. Four responses to changes in forest and plantation cover are discussed: direct effects, with forest loss causing species loss; matrix effects, where plantation loss resulted in species loss; degradation of indigenous forest; and the advent of new forest arising from woody thickening caused by carbon fertilisation, which may not result in optimal habitat for forest-dependent birds.
In order to assess the potential value of differently managed cacao plantations for bird conservation on Sulawesi, we surveyed birds in near-primary forest (with limited timber and rattan extraction, and some hunting), cacao plantations with remnant forest trees and plantations lacking forest trees, from February to April 2007. A total of 16 50 x 50 m plots were visited twice and records of 87 species were obtained. Bird species richness and the number of endemics and forest specialists decreased along this gradient of forest conversion, with 20% of the forest specialists, among them 10 endemics, exclusively found in forest. Species composition changed dramatically between habitat types. Sørensen indices showed a similarity of species composition between forests and plantations of 45–60% for forest specialists and 65–71% for all species. The most important environmental variable for the diversity and composition of birds was the number of remnant rainforest trees present in the plantations. Our results suggest that large, undisturbed rainforest are most important for the conservation of forest specialists and endemics but that cacao plantations, if managed to maintain a high and diverse cover of forest trees, can harbour up to 60% of forest specialists and endemics.
Recent evidence indicates that insectivorous birds in shade coffee farms provide economically significant ecosystem services by reducing insect pests, which should encourage cultivation practices favouring birds and other wildlife. However, the provisioning of this service may be dependent on landscape composition and movement patterns of these mobile consumers. Very little information is currently available on bird movements in coffee-dominated landscapes. We examined roosting behaviour in Black-throated Blue Warblers Dendroica caerulescens on two Jamaican coffee farms using radio telemetry in order to determine whether birds commute between nocturnal roosts and diurnal foraging ranges in coffee habitat. Nocturnal tracking revealed most birds moved outside diurnal foraging ranges on the farms to roost in forested habitat patches, sometimes up to 1 km away. Of 42 roost locations, only eight roosts were within the coffee farm perimeter: one individual in a coffee bush, and seven others in shade trees or vegetated riparian strips. Logistic regression confirmed that birds strongly selected continuous forest and individual trees over coffee for roosting. These findings reflect the ecological connectivity between coffee habitats and the adjacent landscape and raise the possibility that the provisioning of pest reduction services could be at least partly dependent on a farm’s proximity to forest patches.
Following a recent assessment of the distribution and habitat use of Gurney’s Pitta in Myanmar (Burma), further extensive surveys were undertaken in 2010, 2011 and 2012. These have extended the species’ known altitudinal limit to between 250 m and 300 m asl and its latitudinal limit to above 12.5°N, around 80 km north of the northernmost historical record, although the species was recorded far less frequently at higher altitudes and latitudes. Birds were recorded in a range of forested habitats, from intact primary forest to secondary and bamboo forest, with no significant difference between major forest types in the likelihood of occurrence. Niche envelope modelling (MaxEnt) suggested a total range size in Myanmar of 3,379 km2, and did not identify any potentially suitable areas in adjacent parts of Thailand. The species’ preference for warmer, wetter areas on flat ground, conditions ideal for growing oil palm and rubber, suggest that its distribution is likely to contract in the near future. The entire range of Gurney’s Pitta in Myanmar falls within the part of the country most suitable for commercial oil palm production, although the projected yields within its range are low to moderate. Field surveys found evidence of rapid recent deforestation and high levels of hunting and trapping in many parts of the region. The species’ range in Myanmar does not overlap with any protected areas. The protection of southern Myanmar’s biodiversity will require substantial investment by foreign conservation interests, sympathetic land-use planning and the strengthening of environment legislation. Protection of extensive tracts of lowland forest within the range of Gurney’s Pitta, particularly the proposed Lenya National Park and the adjacent Ngawun and Htaung Pru Reserve Forests, is urgently needed. Conserving these areas will also protect populations of other globally threatened bird and mammal species.
The Azure-rumped Tanager Tangara cabanisi is a globally threatened species restricted to the Pacific slope mountains of western Guatemala and Chiapas, Mexico. We studied the habitat use of this tanager on the southern slope of Atitlán volcano, department Suchitepéquez, Guatemala, applying distance sampling along transects in humid broadleaf forest and coffee plantations. The tanager was recorded in both habitat types, but encounter rates were significantly greater in broadleaf forest. The estimated density of tanagers in forest at 1,400–1,900 m was 33–93 birds km−2. Tanagers were recorded mainly in the upper vegetation strata of forest and shade coffee plantations. In coffee plantations tanagers used mainly tall solitary trees or the canopy of shade trees, which were dominated by Inga spp. The number of observations of feeding tanagers in Ficus aurea (Moraceae) indicated a high importance of this food source. The density of F. aurea trees and the encounter rate of tanagers were positively correlated. From 1987 to 2009 tanagers have been recorded at nine topographic units and a total of 16 sites in Guatemala, in the departments of San Marcos, Quetzaltenango, Sololá, Suchitepéquez, and Chimaltenango. We analysed the available habitat for tanagers in the potential area of distribution (1,170 km2), ranging from 900 to 1,900 m altitude and from the Mexican border in the West to the municipality of Pochuta in the East. Broadleaf forest covers 250 km2 or 21% of the potential area of distribution, and coffee plantations cover 800 km2 or 68%. Assuming that population density in prime habitat throughout the potential distribution range is similar to our study area at Atitlán volcano, total tanager population in Guatemala is estimated to be 8,250–23,250 birds. Our findings support the maintenance of the IUCN Red List status of Endangered EN B1a+b(ii,iii,v). To enhance the available habitat for Azure-rumped Tanager, we propose alterations in the shade management of coffee plantations, supported by incentives and certification programmes.
Habitat loss and fragmentation, especially due to agriculture expansion, pose the main threats to biodiversity conservation. While some species are able to survive and proliferate in human-modified habitats (winner species), others are highly dependent on well-preserved habitats, being more vulnerable to extinction (losers). Many raptors can be considered loser species due to their high trophic position, large home ranges, and low reproductive rates. Consequently, this group is frequently used to reflect the environmental quality of habitats and the biodiversity status of communities. Here we describe the diurnal raptor assemblages found in shaded-cocoa agroforests (cabrucas) of Southern Bahia, Brazil, and the determinants of raptor occupancy in this system. We systematically surveyed diurnal raptors in 16 cabruca sites using complementary sampling methods – active search, playback, and point-count – and modeled species occupancy using covariates related to vegetation structure, landscape, management intensity, and biological traits (body mass, trophic level, and diet specialisation). We found a high number of species (at least 18) as able to use cabrucas and a negative relationship between species occupancy and the degree of diet specialisation. Thus, our results suggest that cabrucas have a high potential to mitigate the effects of forest loss and fragmentation on diurnal raptors, but this system alone may not support complete assemblages of this group. It highlights the need for the maintenance of forest remnants in the landscapes to increase species diversity at a regional scale and to assure the conservation of this group in Southern Bahian Atlantic Forest.