No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Bats and birds increase crop yield in tropical agroforestry landscapes
Abstract
Human welfare is significantly linked to ecosystem services such as the suppression of pest insects by birds and bats. However, effects of biocontrol services on tropical cash crop yield are still largely unknown. For the first time, we manipulated the access of birds and bats in an exclosure experiment (day, night and full exclosures compared to open controls in Indonesian cacao agroforestry) and quantified the arthropod communities, the fruit development and the final yield over a long time period (15 months). We found that bat and bird exclusion increased insect herbivore abundance, despite the concurrent release of mesopredators such as ants and spiders, and negatively affected fruit development, with final crop yield decreasing by 31% across local (shade cover) and landscape (distance to primary forest) gradients. Our results highlight the tremendous economic impact of common insectivorous birds and bats, which need to become an essential part of sustainable landscape management.
... Existing predator exclosure experiments have demonstrated that both bats and birds, as predators of arthropods, play vital roles in ecosystem functioning, and their exclusion (i.e., the absence of predators) can lead to significant changes in the ecosystem (Maas et al., 2016). Indeed, they demonstrated the ability to reduce the total abundance and biomass of arthropods in tropical, as well as temperate ecosystems (Böhm et al., 2011;Johnson et al., 2010;Karp & Daily, 2014;Maas et al., 2013;Mooney et al., 2010;Nyffeler et al., 2018). Via top-down control, predators reduce densities of herbivorous arthropods which consequently results in lesser damage to plants (Kalka et al., 2008;Morrison & Lindell, 2012;Van Bael et al., 2003). ...
... However, most of the predator exclosures have been constructed as permanent structures, confounding the effect of birds and bats (Houska Tahadlova et al., 2023;Philpott et al., 2004;Sam et al., 2023). Moreover, the majority of the experiments occurred in agricultural systems (Cassano et al., 2016;Ferreira et al., 2023;Karp & Daily, 2014;Maas et al., 2013;Schmitt et al., 2021) from temperate, neotropical, and Caribbean zones (Maas et al., 2016(Maas et al., , 2019. The emphasis on the agricultural context primarily arises from the threat posed by herbivorous insects to agricultural commodities. ...
... Indeed, insectivorous birds and bats mainly targeted large arthropods (>3 mm) according to earlier studies (Philpott et al., 2004;Van Bael et al., 2003). The rare studies looking for the individual effects of bats and birds have found that both are equally important (Morrison & Lindell, 2012) or that a relative individual effect of bats and birds differs between localities (Kalka et al., 2008;Karp & Daily, 2014), seasons (Williams-Guillén et al., 2008), or landscape context (Maas et al., 2013). Despite the low number of studies, the existing data indicate that the individual effects of birds and bats on arthropod communities are likely to be site-specific because of differences in species and functional richness. ...
Insectivorous predators, including birds and bats, play crucial roles in trophic cascades. However, previous research on these cascades has often relied on permanent predator exclosures, which prevent the isolation of specific effects of birds and bats, given their different activity patterns throughout the day. Moreover, limited knowledge exists regarding the variations in individual effects of these predators under different biotic and abiotic conditions, such as changes in elevation. To address these uncertainties, our study aimed to investigate the distinct effects of bats and birds on arthropod densities in foliage and herbivory damage in lowland and highland rainforests of Papua New Guinea (PNG). Predator exclosures were established for one month to exclude diurnal or nocturnal predators across 120 saplings (ca. 2.5–4 m tall) selected from two lowland and two highland forests (i.e., 30 saplings per study site) along the Mt. Wilhelm transect in PNG. Arthropods were collected and measured, and herbivory damage was analyzed at the end of the experiment. Birds significantly reduced arthropod densities by 30%, particularly in arthropods longer than 10 mm, regardless of elevation. Additionally, both birds and bats appeared to mitigate herbivory damage in highland forests, with protected saplings displaying up to 189% more herbivory. Our results support previous studies that have demonstrated the ability of insectivorous predators to reduce leaf damage through the control of arthropods. Furthermore, our approach highlights the importance and necessity of further research on the role of seasons and elevations in trophic cascades.
... Vertebrate insectivores such as birds and bats are the most wellknown top predators of terrestrial arthropods (Böhm et al., 2011;Johnson et al., 2010;Karp & Daily, 2014;Maas et al., 2013;Mooney et al., 2010;Nyffeler et al., 2018). Previous research, employing diurnal and nocturnal exclusions to differentiate the individual contributions of birds and bats, has generally emphasised significant impacts on arthropod communities attributed to bats alone (Cassano et al., 2016), birds alone (Gras et al., 2016), or both (Kalka et al., 2008;Maas et al., 2013;Morrison & Lindell, 2012;Ocampo-Ariza et al., 2023;Williams-Guillén et al., 2008). ...
... Vertebrate insectivores such as birds and bats are the most wellknown top predators of terrestrial arthropods (Böhm et al., 2011;Johnson et al., 2010;Karp & Daily, 2014;Maas et al., 2013;Mooney et al., 2010;Nyffeler et al., 2018). Previous research, employing diurnal and nocturnal exclusions to differentiate the individual contributions of birds and bats, has generally emphasised significant impacts on arthropod communities attributed to bats alone (Cassano et al., 2016), birds alone (Gras et al., 2016), or both (Kalka et al., 2008;Maas et al., 2013;Morrison & Lindell, 2012;Ocampo-Ariza et al., 2023;Williams-Guillén et al., 2008). Nevertheless, most of these studies were conducted in the tropics, leaving the individual contributions of insectivorous birds and bats to top-down control still poorly understood in temperate regions. ...
... In such instances, their combined impact on arthropod communities equals the sum of the arthropods consumed by each group independently (i.e., additive effect). Although that is the logic, some studies have not demonstrated this additive effect between birds and bats (Maas et al., 2013); and birds and ants (Vansynghel et al., 2022). Nevertheless, acknowledging the distinct dietary preferences observed among ants, birds and bats, we expect that they will evenly and strongly affect arthropod densities and that their effects will be additive [H1]. ...
Birds, bats and ants are recognised as significant arthropod predators. However, empirical studies reveal inconsistent trends in their relative roles in top‐down control across strata. Here, we describe the differences between forest strata in the separate effects of birds, bats and ants on arthropod densities and their cascading effects on plant damage.
We implemented a factorial design to exclude vertebrates and ants in both the canopy and understorey. Additionally, we separately excluded birds and bats from the understorey using diurnal and nocturnal exclosures. At the end of the experiments, we collected all arthropods and assessed herbivory damage.
Arthropods responded similarly to predator exclusion across forest strata, with a density increase of 81% on trees without vertebrates and 53% without both vertebrates and ants. Additionally, bird exclusion alone led to an 89% increase in arthropod density, while bat exclusion resulted in a 63% increase. Herbivory increased by 42% when vertebrates were excluded and by 35% when both vertebrates and ants were excluded. Bird exclusion alone increased herbivory damage by 28%, while the exclusion of bats showed a detectable but non‐significant increase (by 22%). In contrast, ant exclusion had no significant effect on arthropod density or herbivory damage across strata.
Our results reveal that the effects of birds and bats on arthropod density and herbivory damage are similar between the forest canopy and understorey in this temperate forest. In addition, ants were not found to be significant predators in our system. Furthermore, birds, bats and ants appeared to exhibit antagonistic relationships in influencing arthropod density. These findings highlight, unprecedentedly, the equal importance of birds and bats in maintaining ecological balance across different strata of a temperate forest.
... Due to their diverse diet, and expansive foraging range, bats consume different insect species 11,27 . Bats play a major role in the control of insect pests and help suppress pest outbreaks 29,30 . The trophic interactions of bats and the ecosystem services that they provide cannot be compensated by predators such as birds 29,31 . ...
... Bats play a major role in the control of insect pests and help suppress pest outbreaks 29,30 . The trophic interactions of bats and the ecosystem services that they provide cannot be compensated by predators such as birds 29,31 . ...
... Insectivorous bats are known for their ecosystem services by being effective biocontrollers of a wide variety of insect pests of agriculture and horticulture importance 11,29,64,[71][72][73][74] . Boyles et al. 10 have estimated the economic bene ts of bat predation on insect pests to be more than 3.7 billion dollars. ...
We conducted diet analysis of four species of leaf-nosed bats ( Hipposideros hypophyllus , H. durgadasi , H. fulvus , and H. speoris ) cohabiting a roost in the Kolar district, Karnataka, India using metabarcoding fecal DNA technique. We collected fecal pellets of these bats returning to the roost after the first feeding bout over different seasons. The whole diet of all these species consisted of 7,309 OTUs belonging to phylum Arthropoda. Although no significant difference among the whole diets of the four species was found, H. hypophyllus consumed the most amount of insect taxa (4,114 species) compared to others. The core diets consisted of 49 taxa belonging to 10 orders, 37 families, 46 genera. A significant difference was found among the core diets, with H. hypophyllus and H. speoris feeding on more varied insects. There was no overlap in diets and the bat species were observed to be diet specialists. Prey items belonging to orders Lepidoptera and Diptera were abundant in the diet of all four species of bats. The core diet of H. hypophyllus varied significantly between the seasons, with greater than 70% intake of lepidopteran insects in the monsoon and winter seasons. Our study reveals that these bats feed on insect pests too thus playing a role as biocontrollers.
... Hops are attacked by variety of pests, including insects (Gargani et al. 2017), and it is of farmers' interest to seek for efficient, easy to implement, and cheap way how to reinforce pest control. Nesting insectivorous birds may provide important ecosystem services to local farmers as birds are frequently feeding on insects and other crop pests, and consequently enhancing pest biological control in the agriculture (Maas et al. 2013, Milligan et al. 2016, García et al. 2018, Díaz-Siefer et al. 2022. ...
... Provisioning of poles with cavities or nest boxes in hop and other crop plantations may represent an efficient and cheap way how to reinforce pest control in plantations and meet the goals of sustainable agriculture (Tscharntke et al. 2012, Maas et al. 2013, García et al. 2018, Díaz-Siefer et al. 2022. For example, hop plantations in the study region were damaged repeatedly by outbreaks of Rosy Rustic Moth Hydraecia micacea (Weihrauch 2020). ...
... For example, hop plantations in the study region were damaged repeatedly by outbreaks of Rosy Rustic Moth Hydraecia micacea (Weihrauch 2020). The positive effect of bird diversity, particularly insectivorous birds, on crop damage by pests and crop yields has been demonstrated in different agroecosystems (Maas et al. 2013, Nyffeler et al. 2018, but see Martínez-Núñez et al. 2021, although also generalist bird species may significantly contribute to the pest predation (Garcia et al. 2020). Currently, traditional wooden poles in hop plantations are increasingly replaced by metal and concrete ones (Van Kerckhoven et al. 2020, European Commission 2023b with the latter two types being less used by birds than the wooden poles. ...
Hops (mainly Humulus lupulus varieties) are a globally significant agricultural crop, known mainly for their use in the brewing industry. Hop plantations create unique habitats for birds, with structural poles potentially serving as nesting sites for cavity nesting birds. We surveyed 321 hop plantations (inspecting 100 random poles in each) during the 2023 breeding season in Bavaria, Germany, and examined structural poles for the presence of nesting birds. We found 219 breeding pairs of 11 cavity-nesting species. The most frequent nesting species were Common Starling Sturnus vulgaris, Tree Sparrow Passer montanus, and Great Tit Parus major. The most nesting cavities were found in wooden and concrete poles, while metal poles were largely avoided. Nesting sites in metal and concrete poles were often selected due to structural imperfections, whereas wooden poles contained mainly cavities excavated by woodpeckers. We advocate for the retention of wooden poles over concrete/metal poles, as they are crucial nesting sites for birds which are important in pest control in hop plantations. For modern hop plantations with non-wooden poles, we recommend the use of nest boxes which can compensate for the loss of nesting sites and support local breeding bird populations.
... A broadly applied method to quantify the effects of wildlife on crop yields in tropical and temperate countries involves using experimental exclosures (Ancillotto et al., 2024;Ferreira et al., 2023;Maas et al., 2013;Maas et al., 2019;Maine and Boyles, 2015;Rodríguez-San Pedro et al., 2020). An exclosure consists of a structure covered with a mesh net that works as an exclusion cage. ...
... Focusing on vertebrates, exclosures have typically been applied to assess the control services offered by birds (Garfinkel and Johnson, 2015;Kellermann et al., 2008;Martin et al., 2013;Redlich et al., 2018). However, they are also increasingly being used to study the effect of bats as pest suppressors (Ancillotto et al., 2024;Beilke and O'Keefe, 2023;Ferreira et al., 2023;Maas et al., 2013;Maine and Boyles, 2015;Rodríguez-San Pedro et al., 2019;Williams-Guillén et al., 2008). Several authors have demonstrated this technique's efficiency in assessing the role of insectivorous bats on arthropod population regulation and estimating the value of their ecosystem services. ...
... Several authors have demonstrated this technique's efficiency in assessing the role of insectivorous bats on arthropod population regulation and estimating the value of their ecosystem services. For example, in cacao plantations in Indonesia, Maas et al. (2013) reported an increase in cacao yields by more than 31 % where bats were not excluded, saving (along with birds) $730/ha each year. Another study carried out in vineyards in Chile detected relevant differences in crop yield between control and excluded areas, valuing the suppression services of bats at $188 -$248/ha/year (Rodríguez-San Pedro et al., 2019). ...
... However, the idea has had a resurgence in recent years [31], partly due to increased interest in sustainable land management [32]. In particular, it has been shown that a number of insectivorous solitary birds are effective biological controls [33][34][35][36][37]. In addition, while their effectiveness has not been investigated, there are numerous anecdotal observations of individual birds eating lanternflies [38]. ...
... Suggesting, perhaps, that if there were no tree of heaven, or other quassinoid producing plants, birds and other predators may begin to consume lanternfly in sufficient quantities to contribute to controlling the population. While this process might be slow with solitary birds like those featuring in [33][34][35][36][37], in group living social birds, like the great tit (P. major), this process might be more rapid. ...
... In particular, social birds can go wherever the lanternfly is present without manual distribution, they are an environmentally better option than insecticides [32], and their efficacy could potentially be substantial if they start consuming lanternfly collectively. Given that even solitary birds are effective biological controls [33][34][35][36][37], insectivorous birds are key controllers of insects globally [61], and animal collectives often are supremely effective foragers [40,41]. Perhaps they can even help mediate a particularly persistent issue with conventional controls, namely that the last few pest organisms are the most difficult to find and eliminate. ...
The spotted lanternfly is an emerging global invasive insect pest. Due to a lack of natural enemies where it is invasive, human intervention is required. Extensive management has been applied but the spread continues. Recently, the idea of bird-based biological controls has re-emerged and shown effective in studies. However, it is questionable, if birds are able to effectively control unfamiliar and occasionally toxic invasive pests in short timeframes. Unless, perhaps, the birds are effective social learners and toxicity of the invaders is rare. Here, we introduce a mathematical model for social learning in a great tit-like bird to investigate conditions for the emergence of a collective biological control of a pest that is occasionally toxic, like the lanternfly. We find that the social observation rate relative to the proportion of toxic lanternfly dictate when collective biological controls will emerge. We also implement the social learning model into a model of collective motion in bird-like animals, and find that it produces results consistent with the mathematical model. Our work suggests that social birds may be useful in managing the spotted lanternfly, and that removing the toxicity-inducing preferred host of the lanternfly should be a priority to facilitate this.
... Maas et al., 2016;Librán-Embid et al., 2017). In one of the few studies to date focusing on these taxa in cacao plantations , exclosure experiments from Indonesia revealed that insect predation by bats and birds increased yield by 31 % and saved farmers 730 dollars per ha annually (Maas et al., 2013). Although this shows the potential of bats and birds as cacao pest suppressors, the African bird, bat and arthropod communities and their trophic interactions are entirely different from those found in Southeast Asia (Bagny Beilhe et al., 2018;del Hoyo, 2020;Taylor and Tuttle, 2019;Tscharntke and Hawkins, 2002) and no study has yet been conducted in Central/West Africa, even though most cacao is produced in this region. ...
... Arthropods groups were classified as pests (mealybug and S. singularis), phytophagous, predatory, or potential pollinators depending on their main diets and roles in cacao plantations (Cassano et al., 2016;Toledo-Hernández et al., 2017;Wessel and Quist-Wessel, 2015). For logistical reasons we were not able to conduct the arthropod monitoring as in Maas et al. (2013), thus we only sampled trees between 8 AM and 5 PM in each landscape. However, sampling always occurred at the same time of the day for each tree to avoid differences due to arthropods' activity patterns between visits (Awudzi et al., 2017;Azhar, 1986) and to be able to look for consistent patterns throughout the 12 months. ...
... Similar to an exclusion experiment conducted by Maas et al. (2013) in Indonesia, which found differences in yield between treatments but no differences in the abundance of the main pests and their pod damage, the main cacao pest in our study system, S. singularis, did not vary significantly with the absence of bats and birds ( Fig. 2A). However, this species is particularly difficult to detect, occurring normally in densities of two adult individuals per tree and being mostly active around sunrise (Babin et al., 2010). ...
Sub-Saharan Africa produces most of the Earth’s cacao. Although pests cause losses of hundreds of millions annually, the role of cacao pest suppressors remains unknown. We used an exclusion experiment to prevent access of bats and birds to cacao trees and quantified how their absence affected arthropod communities, herbivory, and crop yield. Overall, Mealybugs and other hemipteran pests were more abundant in exclosures. Under heavy shade (90%), cacao trees with vertebrate exclosures had 3.9 times fewer flowers and 3.2 times fewer large pods than control trees, corresponding to losses on average of 796 ha-1y-1. Our study demonstrates that the enormous potential of African bats and birds as pest suppressors is dependent on shade tree management.
... Globally, insectivorous bats are estimated to prevent the loss of up to 50% of crops by feeding on such pests (Pimentel et al., 1978) and thereby yield strong economic benefits (Table 15.1). In an Indonesian cacao (Theobroma cacao) plantation, bat exclusions lead to a decrease in the numbers of seeds produced and fruits harvested (Maas et al., 2013). When birds and bats are excluded, there is a 326 kg/ha loss of cacao yield, which translates to a loss of 730 USD/ha (Maas et al., 2013). ...
... In an Indonesian cacao (Theobroma cacao) plantation, bat exclusions lead to a decrease in the numbers of seeds produced and fruits harvested (Maas et al., 2013). When birds and bats are excluded, there is a 326 kg/ha loss of cacao yield, which translates to a loss of 730 USD/ha (Maas et al., 2013). For corn, pest suppression by bats is estimated to be worth more than 1 billion USD per year (Maine and Boyles, 2015). ...
... Although bats provide many benefits through foraging, their behaviors may also adversely affect ecosystem services. For example, insectivorous bats also feed on predatory arthropods, which may lead to a release of pest suppression at a lower trophic level (Maas et al., 2013). Experimental bat exclusions in agriculture show an increase in predatory spiders and ants in agriculture (Maas et al., 2013); however, some evidence suggests this does not affect yield (Denmead et al., 2017). ...
... La estructura del paisaje tiene consecuencias importantes para los servicios de regulación de plagas proporcionados por muchas especies con requisitos específicos de hábitat (Maas et al., 2018). Del mismo modo, la complejidad del paisaje con hábitats heterogéneos aumenta la diversidad de los depredadores naturales y, al mismo tiempo, puede mejorar los servicios de regulación de plagas (Bianchi et al., 2006). ...
... tural dentro de las plantaciones (es decir, el helecho de tierra y epífito) proporciona sitios de anidación para las aves insectívoras, que pueden controlar a los que se alimentan de hojas (Koh, 2008a;Koh 2008b). Al mismo tiempo, los bosques en los sistemas agrícolas promueven poblaciones de potenciales depredadores y polinizadores como aves, murciélagos e insectos (Maas et al., 2018). En última instancia, la polinización y el control de plagas pueden producir un efecto indirecto en el rendimiento de los cultivos (e.d un aumento en estos) (Maas et al., 2018;Tscharntke et al., 2007). ...
... Al mismo tiempo, los bosques en los sistemas agrícolas promueven poblaciones de potenciales depredadores y polinizadores como aves, murciélagos e insectos (Maas et al., 2018). En última instancia, la polinización y el control de plagas pueden producir un efecto indirecto en el rendimiento de los cultivos (e.d un aumento en estos) (Maas et al., 2018;Tscharntke et al., 2007). ...
In Colombia, oil palm is an important economic sector of the agroindustry. One of its main challenges is to simultaneously ensure palm oil production growth and maintain and improve the local environment and a sustainable agricultural landscape. Thus, we conducted a landscape analysis on an exemplary palm oil plantation to assess the landscape structure and complexity, and land-use change between 2009 and 2019. The case study is done in the Macondo oil palm plantation, located in Mapiripán, Meta, in the eastern zone of Colombia with a total area of 5,853 hectares. The landscape analysis is based on a 2009 land cover maps GIS analysis. First, the land cover map of the plantation was divided into grid cells of 500 by 500 meters. Second, we applied landscape metrics for the landscape structure assessment and calculated a k-means cluster analysis. The grid cells were clustered into nine (9) similarity groups based on landscape metrics. Four (4) squares per group, in a total of 36, were selected as a sample of the plantation. For each selected square, we took aerial photography at a height of 100 meters to create the orthophotos. The aerial photographs were taken using Unmanned Aerial Systems (UAS), in this case, a DJI drone, and enabled us to take over 10,800 aerial photographs in 10 days. Aerial photography provides detailed and up-to-date information on land cover and land use change, which is essential for monitoring and decision-making. This type of landscape analysis enables managers of oil palm plantations to monitor land cover change and the implemented Landscape Management Tools (LMT) within the plantation.
... La estructura del paisaje tiene consecuencias importantes para los servicios de regulación de plagas proporcionados por muchas especies con requisitos específicos de hábitat (Maas et al., 2018). Del mismo modo, la complejidad del paisaje con hábitats heterogéneos aumenta la diversidad de los depredadores naturales y, al mismo tiempo, puede mejorar los servicios de regulación de plagas (Bianchi et al., 2006). ...
... tural dentro de las plantaciones (es decir, el helecho de tierra y epífito) proporciona sitios de anidación para las aves insectívoras, que pueden controlar a los que se alimentan de hojas (Koh, 2008a;Koh 2008b). Al mismo tiempo, los bosques en los sistemas agrícolas promueven poblaciones de potenciales depredadores y polinizadores como aves, murciélagos e insectos (Maas et al., 2018). En última instancia, la polinización y el control de plagas pueden producir un efecto indirecto en el rendimiento de los cultivos (e.d un aumento en estos) (Maas et al., 2018;Tscharntke et al., 2007). ...
... Al mismo tiempo, los bosques en los sistemas agrícolas promueven poblaciones de potenciales depredadores y polinizadores como aves, murciélagos e insectos (Maas et al., 2018). En última instancia, la polinización y el control de plagas pueden producir un efecto indirecto en el rendimiento de los cultivos (e.d un aumento en estos) (Maas et al., 2018;Tscharntke et al., 2007). ...
... Plots were randomly distributed within the cabruca and with an approximate 100 m distance between each plot as selection criteria. We measured the shade tree canopy cover (%) per plot with digital photographs (i.e. 4 images randomly taken with a 13 mm wide-angle lens, 4 m above the ground and under sunny conditions) and used the software image J (Maas et al., 2013;Wanger et al., 2010). We then allocated plots in either the low (0-30%) or high (70-100%) canopy cover category. ...
... For instance, a lower canopy cover may reduce competition for light, nutrients and water (Blaser et al., 2018), hence resulting in more energy resources for sustaining fruits, than cocoa trees under shade trees with high canopy cover. On the other hand, low canopy cover, may also promote losses associated to cherelle wilt and pathogen attacks (Bos et al., 2007b), and overall loss of ecosystem services such as carbon sequestration (Niether et al., 2020), soil fertility (Dechert et al., 2005) and biological control (Maas et al., 2013). Therefore, a shade tree canopy cover management to a recommended 40-50% Steffan-Dewenter et al., 2007) may be a reasonable trade-off between high productivity and environmental benefits. ...
... Habitat and resources for pollinators, and other important beneficial organisms (e.g. bird and bat insect predators; Maas et al., 2013;Vansynghel et al., 2022b) can be enhanced through farm (e.g. preserving soil organic nutrients; Frimpong et al., 2011;Young, 1982) and landscape (e.g. ...
Agricultural diversification can enhance climate resilience, biodiversity conservation, and livelihood in global farming systems. Diverse agroforestry systems with cocoa have been shown to provide all these benefits, but the often-lower yields compared to monocultures limit agroforestry adoption by smallholder farmers. Cocoa yield is pollination-limited, and here, we quantified the effect of hand pollination in cocoa on fruit set, fruit abortion or cherelle wilt, pest and diseases, and number of mature fruits. Experiments were conducted in Bahia, Brazil, along a shade gradient from low [10-30%] to high [70-100%] canopy cover and with cocoa trees grafted with high-yielding varieties. We found on average 331% fruit set, and 300% mature fruit increase (i.e. ripe pods) per tree by enhancing pollination by hand as little as 10% of the flowers/tree, compared to the control (i.e. with only natural pollination). Fruit set, fruit losses, and mature fruit development linked to hand pollination was higher in low compared to highly shaded cocoa areas. We found 31% higher fruit set and 37% higher number of mature fruits in grafted than un-grafted trees. Further, when comparing efforts invested in hand pollination, minimum labor (~5 min/tree to pollinate 10-30% of the flowers/tree) led to a 871% fruit set and a 750% mature fruit increase under low canopy cover, and intermediate labor (~15 min/tree to pollinate 40-60% flowers/tree) to a 629% fruit set under high canopy cover. As ~5-15 min/tree hand pollination can substantially enhance fruit set and number of mature fruits in low as well as high shade management, we recommend performing hand pollination particularly in agroforests under 40-50% canopy cover to create win-win opportunities for high productivity and climate resilience. Future research should focus on the wide range of agroforestry, tree grafting and innovation strategies in all major production regions to capture the long-term variability of hand pollination as a basis to scale-up hand pollination for sustainable cocoa production globally.
... The Guinea Savannah, Sudan Savannah, Transitional, Semi-deciduous, and Coastal Savannah agro-ecological zones in Ghana were examined. The Guinea, Sudan, and Coastal Savannah agro-ecological zones, for instance, are unique in that they lack the diverse landscapes that provide shelter and perches for preying birds, parasites, predators, and other natural enemies that mitigate against the damage of FAW invasion (Maas et al. 2013;Baudron et al. 2019;Harrison et al. 2019). Maize farmers in these zones recorded higher levels of larval infestations during the 2016 to 2018 maize production seasons (Koffi et al. 2020). ...
... We expect the probability of adopting FAW management practices by maize farmers in these zones to be higher. The Semi-deciduous agro-ecological zone, on the other hand, is characterised by big trees and thick forests, which enhance the abundance of birds and bats as natural enemies of FAW pests (Maas et al. 2013(Maas et al. , 2016Baudron et al. 2019). Therefore, we expect the Semi-deciduous agro-ecological zone dummy to exert a negative effect on the adoption of FAW management practices. ...
One of the emerging challenges impinging on sustainable food production in sub-Saharan Africa is the invasion of the fall armyworm (FAW) pest. Data collected from farm households in different agro-ecological zones in Ghana and a Multivalued Treatment Effect (MVTE) model were used to argue that FAW management practices are key to stemming the debilitating effects of FAW infestations on farm performance. Previous studies have analysed homogeneous treatment effects to explain FAW management practices. The present study employs heterogeneous treatment effects to account for the differential effects of FAW management practices such as early planting, application of prescribed pesticides, and a combination of both practices while accounting for socioeconomic characteristics. Findings from the study reveal that distance to extension services exerts negative effects on adoption of early planting only, and adoption of both FAW management practices. Moreover, past FAW infestations tend to exert a positive effect on adoption of pesticide application only and adoption of a combination of the FAW management practices. Adopting the FAW management practices examined in this study assisted the maize producers in raising their farm performance. Socioeconomic characteristics also tend to influence the homogeneous treatment effects of adoption of the FAW management practices on farm performance. This finding indicates that heterogeneity within farm households is crucial for policy regarding adoption of FAW management practices.
... Trees are likely to enhance the abundance of birds and bats (Figs. 1-10) and increase their role as natural enemies of FAW (Maas et al., , 2013. Bats in particular may be important control agents of the adult moths (Boyles et al., 2011;Lee and McCracken, 2005;Maine and Boyles, 2015). ...
... Maintaining remnants of forest in agricultural landscapes can be effective for conservation of arthropod biodiversity and contribute to biological control in adjacent crop fields (Landis et al., 2000;Veres et al., 2013). Forest patches near crop plantations have been shown to increase the local abundance and diversity of natural enemies, such as predatory solitary wasps and insectivorous birds and bats (Boyles et al., 2011;Jones et al., 2005b;Maas et al., 2013Maas et al., , 2016Sousa et al., 2011). Sousa et al. (2011) evaluated the influence of forest distance on predatory solitary wasp abundance and richness and its relation to the natural biological control of FAW in maize fields in Brazil. ...
... Their analysis across European countries quantified the relative importance of four widespread anthropogenic drivers: agricultural intensification, urbanization, changes in forest cover, and climate change. They identified agricultural intensification as the major cause for the decline of most bird populations, especially invertebrate feeders, which are known to be of major importance for biological pest control (2). Urbanization also affected birds' population dynamics negatively, while forest cover had no overall effect, and effects of temperature change depended on the species' thermal preference. ...
... There are winners and losers of land-use change, depending on traits such as diet preferences. For agriculture, the most important driver of species losses, the negative effects of agricultural intensification on insect feeders are particularly annoying, as this indicates a strong reduction in biological pest control (2). Agricultural intensification goes far beyond agrochemical use, and future research should consider a landscape perspective considering the beneficial role of small and diversified fields as well as a minimum of semi-natural habitat (6). ...
... In addition to insect pests, exclusion netting has also been used to evaluate the impact of birds (Kuesel et al. 2019) and bats (Maas et al. 2019;Tollington et al. 2019) on crop yields. Though exclusion is widely used to protect crops, this strategy does not always increase crop yield (Maas et al. 2013). For example, a study on the coffee berry borer in Hawai'i assessed the impact of mesh netting on borer infestation levels, coffee quality, and coffee yield (Johnson et al. 2020). ...
Losses in crop yield due to invasive insects, weeds, pathogens, and herbivores cost trillions of dollars per year globally. To prevent further spread of invasive agricultural pest species, continuous monitoring and prevention are crucial. Once introduced, however, assessing the impact of an invasive pest on agricultural production and testing management strategies are essential. The green iguana (Iguana iguana), a globally widespread invasive herbivore, is considered a possible agricultural pest although no quantitative data on its impact are available. In this study, we evaluated the impact of the invasive green iguana on cucumber (Cucumis sativus, var. Dasher II) and lettuce (Lactuca sativa, var. Black-seeded Simpson) yield by testing the efficacy of two management strategies – Neem-based pesticide and mesh fencing – compared to open field cultivation in Puerto Rico. Mesh fencing led to 20% more growth and doubled cucumber yield compared to open field cultivation, while spraying Neem led to an 18% increase in plant growth but no effect on cucumber yield. We found no difference in lettuce growth or yield among treatment and control plots. This study supports categorizing the green iguana as an invasive agricultural pest species and demonstrates the reptile’s potential to reduce crop yield. It also shows that Neem application at the manufacturer’s suggested concentration is not an effective mitigation technique for reducing crop loss due to green iguana herbivory. Government agencies in regions where the green iguana has the potential to be introduced should consider the species a threat to food production when developing monitoring programs and drafting regulations.
... Bats can be found within agricultural environments across the world and are responsible for several ecosystem services, including pollination, dispersal of seeds and suppression of insect populations (Boyles et al., 2011;Kunz et al., 2011;Russo et al., 2018;van Toor et al., 2019;Fill et al., 2022). Studies conducted in cacao plantations in Asia (Maas et al., 2013) and South America (Vansynghel et al., 2022) showed that pest suppression by bats and birds increased yield independently of plantation management by 31 % and 114 %, respectively. Also, a study conducted in Africa showed that bats and birds can save farmers an average of $478 per ha per year through pest consumption-but only when high shade tree cover is maintained (Ferreira et al., 2023a). ...
... Departures from generalized expectations of both impacts and dependencies on biodiversity were found for bats, birds, non-flying vertebrates and spiders across multiple cropping systems. Most of the studies on the benefits of flying predators did not consider birds and bats separately [63,64]. In the few studies that did separate effects, benefits from bats were lower [65,66], suggesting that birds may have driven most of the service provision in the mixed studies. ...
Compelling evidence for feedbacks between commodity crop production systems and local ecosystems has led to predictions that biodiversity loss could threaten food security. However, for this to happen agricultural production systems must both impact and depend on the same components of biodiversity. Here, we review the evidence for and against the simultaneous impacts and dependencies of eight important commodity crops on biodiversity. We evaluate the risk that pollination, pest control or biodiversity-mediated soil health maintenance services are at risk from local biodiversity loss. We find that for key species groups such as ants, bees and birds, the production of commodities including coffee, cocoa and soya bean is indeed likely to be at risk from local biodiversity loss. However, we also identify several combinations of commodity, ecosystem service and component of biodiversity that are unlikely to lead to reinforcing feedbacks and lose–lose outcomes for biodiversity and agriculture. Furthermore, there are significant gaps in the evidence both for and against a mutualism between biodiversity and agricultural commodity production, highlighting the need for more evaluation of the importance of specific biodiversity groups to agricultural systems globally.
... Examples of these include their ability to fly, thus being able to migrate distances of more than 2000 km [3,4]; extreme longevity (of more than 30 years) compared to non-flying mammals of similar body size; daily torpor; and seasonal hibernation [5]. As major nocturnal aerial predators, they significantly contribute to natural crop pest control [6][7][8]. ...
Here, we report the results of a monitoring study of bat viruses in Austria to strengthen the knowledge of circulating viruses in Austrian bat populations. In this study, we analyzed 618 oropharyngeal and rectal swab samples from 309 bats and 155 pooled tissue samples from dead bats. Samples were collected from 18 different bat species from multiple locations in Austria, from November 2015 to April 2018, and examined for astroviruses, bornaviruses, coronaviruses, hantaviruses, morbilliviruses, orthomyxoviruses (influenza A/C/D viruses), pestiviruses and rhabdoviruses (lyssaviruses) using molecular techniques and sequencing. Using RT-qPCR, 36 samples revealed positive or suspicious results for astroviruses, Brno-hantaviruses, and coronaviruses in nine different bat species. Further sequencing revealed correspondent sequences in five samples. In contrast, none of the tested samples was positive for influenza viruses A/C/D, bornaviruses, morbilliviruses, lyssaviruses, or pestiviruses.
... Preventing outbreaks of pathogens by monitoring these mammals should be a priority for public policies in Brazil, as they are cost effective and can save human lives (Winck et al., 2022). Regulatory species that deliver pest and disease control service, on the other hand, contribute to increasing crop yields and food security, reducing the need for pesticides, improving ecosystem integrity and human health (Maas et al., 2013;Wanger et al., 2014). ...
... In contrast, it is likely that in the subtropical rainforest specialized insectivores relying on, for example, complex understory vegetation fail to find an adequate microhabitat in agroforestry areas (e.g., Ocampo-Ariza et al., 2019;Powell et al., 2015). Considering that biocontrol services by insectivorous birds are known to contribute significantly to cacao yield in Peru and elsewhere in the tropics, (Ferreira et al., 2023;Maas et al., 2013;Vansynghel et al., 2022), cacao agroforestry in subtropical forest landscapes should prioritize enhancing microhabitat conditions for insectivores to maintain their benefits for cacao productivity. ...
Diversity and functionality of bird communities in tropical agroforests are shaped by their surrounding landscape, particularly the extent and type of natural forest. However, most evidence comes from tropical rainforest landscapes, whereas the bearing of such trends in other forest types remains understudied. We compared functional and beta diversity of bird communities in 23 cacao agroforests embedded in landscapes of two contrasting Peruvian regions: seasonally‐dry tropical forests and subtropical rainforests from the Andean foothills. Strong climatic seasonality affects both landscapes, but forest vegetation structure and complexity differ. We found higher bird species richness (n = 179 spp) and higher species turnover in the subtropical forest than in the dry forest landscape (n = 64 spp). Only in the dry forest landscape, distance from forest increased dissimilarity driven by species loss, that is, the nestedness component of beta diversity. This points to the importance of conserving dry tropical forests within the broader landscape matrix, with known benefits for pest control and cacao yield. Functional diversity indices were not influenced by forest distance in either landscape, but the proportion of insects in birds' diet decreased by 27% along a 1 km distance gradient from forest in the subtropical forest landscape. In the dry forest landscape, however, it decreased by only 3% across the same distance gradient. Far from forest (≥1 km), forest specialization decreased by ~33% and 20% in the subtropical and dry forest landscapes, respectively. These differences indicate that regionally‐adapted agroforest management is paramount for conserving bird diversity and ecosystem services as pest control. Procuring high‐canopy shade trees and adequate microhabitats for insectivorous species is essential to maintain biocontrol services in the subtropical forest. Conversely, in the dry forest enhancing low‐canopy vegetation with a focus on frugivores and ensuring forest closeness to agroforests may maximize bird diversity and their ecosystem services. A complete version of this article is translated to Spanish in the supplements.
... Contrarily, nature-based solutions for suppressing pests, such as biological control, are a cheap and sustainable alternative to the use of chemical pesticides (Bommarco et al., 2013;Naranjo et al., 2015). Pest consumption services provided by insectivorous bats and birds are a nature-friendly way of regulating pest populations as revealed by numerous studies conducted in different regions and agricultural systems (Karp et al., 2013;Maas et al., 2013;Xavier et al., 2023), including rice paddies (Puig-Montserrat et al., 2015;Tuneu-Corral et al., 2024;Wanger et al., 2014). However, a positive effect by these predators on rice yield is not always detected (e.g., Bhalla et al., 2023;Borkhataria et al., 2012). ...
... Vertebrates pollinate a wide variety of economically and ecologically important plants across tropical and subtropical regions (Law and Lean 1999;Yumoto 2000;Ollerton et al. 2011;Maas et al. 2013). From among these regions, the highly biodiverse subcontinent of India is known to host a range of vertebrate species that pollinate a wide variety of plant species of significant economic importance for the country (Atluri et al. 2000;Nathan et al. 2005;Sinu et al. 2011;Erancheri et al. 2013;Raju et al. 2013;Khanduri and Kumar 2017). ...
Animal pollinators underpin the functioning and persistence of ecosystems globally. However, the vital role of pollination is being progressively eroded by the worldwide decline of pollinator species caused by human-induced environmental degradation, resulting in rising costs to biodiversity, agriculture, and economy. Most studies quantifying pollinator diversity and declines have focused on insects, whereas vertebrate pollinators remain comparatively neglected. Here, we present the first comprehensive study quantifying the macroecological patterns of species richness and extinction risk of bird and mammal pollinators in India, a region of extremely high biodiversity and increasing anthropogenic pressure. Our results reveal that hotspots of mammal pollinator diversity are restricted to the south of the Western Ghats, whereas bird pollinator diversity hotspots are scattered throughout the country. Analyses of hotspots of threatened species (based on the IUCN Red List) show that only mammal pollinators are currently classified as threatened in India, whereas multiple hotspots of population declines were observed for birds, and primarily in the Southwest for mammal pollinators. Our analyses failed to identify a role for species traits as drivers of these patterns, whereas most pollinators appear to be threatened by agriculture, logging and hunting for food, and medicinal purposes. Pollinator endangerment has widescale ecological and economic implications such as reduced food production, plant extinction, loss of functional and genetic diversity, and economic damage. We suggest protection of vertebrate pollinators should be emphasised in active conservation agendas in India.
... Bats as efficient pest insect population controllers. Some of the insect pests that bats control include: Coleoptera, Diptera, Hemiptera, Odonata, Isoptera, dan Lepidoptera [7][8][9][10][11][12]. This role can lower the cost of pest control. ...
Bats have an important role in the ecosystem as seed spreaders, pollinators, insect controllers, and nutrient recyclers. However, there is no comprehensive review that evaluating the role of bats across biogeography in Indonesia. The purpose of this study is to study the role of bats as insect controllers, seed dispersers, and pollinators based on the results of research over the last 2 decades in Indonesia. The data collected by research to published research with different keywords that covers different ecosystem of the bats. This review summarizes the importance of conserving bat populations and the ecological services they provide. It is reviewed bat-related literature published over the past two decades, with a total of 46 relevant literatures of the total literature, 47.8% studied bat diversity, 13% diversity and ecology, 17% studied its role as a pest control, 13% studied its role as a pollinator, and 8.7% studied its role as a seed disperser. The findings show that bat-related research in Indonesia has experienced an upward trend since 2003-2023. This study can be used as a basis for sustainable conservation efforts and aiming at achieving the goals of SDGs.
... Birds are also excellent pollinators of many plants, with different pollinating species distributed worldwide (Cronk and Ojeda, 2008;Nicolson, 2002;Stiles, 1981). Although birds are often associated with fruit damage and yield losses in agricultural systems (Anderson et al., 2013;Tracey et al., 2007), they can also provide pollination services in some food crops, including cacao (Gras et al., 2016;Maas et al., 2013), coffee (Coffea spp.; Rubiaceae; Chain-Guadarrama et al., 2019), and rabbiteye blueberry (Vaccinium spp.; Santos et al., 2023a, b). In addition to pollination services, birds can also provide other critical ecosystem services within agroecosystems (Denmead et al., 2017;Whelan et al., 2008). ...
Fruits and vegetables can vary significantly in their dependence upon insect pollinators to transfer pollen. Raspberry and blackberry are two fruits that are regarded as highly-pollinator dependent. This means that knowledge of pollinator foraging behaviour, efficiency at transferring pollen, and interactions between pollinators, flowers, and the surrounding environment, are all critical factors to understand in depth to ensure that pollination service delivery is optimised. Bees have generally been acknowledged as the most important crop pollinators, yet their efficiency can vary in response to various factors including timing of the visit, previous visits, hive health, flowers available and interactions with other taxa. Further, even though we know other insects visit crop flowers, little is known about the pollination services provided by animals other than bees (i.e., non-bees) and their capacity to transfer pollen effectively. We also have a limited understanding about the number and quality of flower visits required in different cultivars and systems to achieve the best fruit quality. Finally, the resources pollinators require in different seasons and landscapes and the environmental conditions in which berry plants are grown, can also mediate the likelihood of pollination success. This presentation will outline a number of research findings that could be used to support greater resiliency with regard to insect pollination needs of Rubus and Ribes. These include understanding the contribution of different flower visitors and their efficiency in providing pollination services, a greater understanding of pollinator resource needs to improve their longevity in orchard environments, the conditions in which plants are most responsive to pollination service delivery and the importance of collaborations between industry and researchers to manage the system sustainably and to optimise fruit production and quality.
... Cockroaches form a significant part of the diet of some insectivorous bat species (Belwood, 1988;Willig et al., 1993;Churchill, 1994;Aspetsberger et al., 2003;Rakotoarivelo et al., 2009). Other studies suggest that several bat species opportunistically feed on non-flying cockroaches (Link et al., 1986;Whitaker and Karataş, 2009;Taylor et al., 2017;ter Hofstede et al., 2017;Andriollo et al., 2019), with bats also serving as population controllers of cockroaches in agroforestry crops of economic interest (Maas et al., 2013(Maas et al., , 2015Taylor et al., 2017). ...
... Bats are the response variable of the ecosystem health and environmental changes (Jones et al., 2009). Bats are important pollinator and seed dispersal for tropical forest and also provides the essential insect pest (Muscarella & Fleming 2007;Kalka et al., 2008;Williams-Guillén et al., 2008;Kunz et al., 2011;Maas et al., 2013). ...
Bats use the landscape as their habitat to thrive and survive for years and have high site fidelity for their traditional roosting places. This is highly collaborated with other
cofactors like optimum humidity and temperate. Over the years of anthropogenic activities at the landscape level, bats also explore them as an opportunity to expand their species distribution range as well and the same can have a negative
impact too. The present study gives an opportunity to understand this in the Thar Desert of Rajasthan and the outcome is interesting to extrapolate the hypothesis. In
Western Rajasthan, we explored three major districts namely Jodhpur, Jaisalmer and Barmer. Over the years urbanization in Jodhpur has led to habitat loss for bats, Barmer become a hub of many horticulture crops due to many affirmative and promotional schemes by the Government and large areas of Jaisalmer are now under
agriculture, left a negative impact on the vast open habitats in desert country. Bats are very sensitive towards their habitat change and this can be understood from the way landscape-level changes.
... Bats serve as excellent indicators of ecosystem health (Fenton et al. 1992;Jones et al. 2009). They provide vital ecosystem services, such as seed dispersal and pollination, participating in the reproductive cycles of plants, contributing to both landscape regeneration and to the regulation of arthropod populations (Muscarella andFleming 2007: Kalka et al. 2008;Kunz et al. 2011;Maas et al. 2013). Unfortunately, tropical bats, and consequently their ecosystem functions, are threatened in a partially predicted future by the combined effects of habitat conversion and climate change (Kingston 2013;Struebig et al. 2015), and by the still littleknown effects of emerging disease impacts (e.g., Langwig et al. 2016). ...
Neotropical bats are known for their extraordinary taxonomic, functional, and phylogenetic diversity, and for the ecosystem services they provide through seed dispersal, pollination, and control of insect populations. This diversity is unarguably unique in the Amazon, and hitherto there are many gaps in the knowledge of these spectacular mammals throughout this biome. We herein conducted a broad analysis with tests of the heterogeneity in bat species distribution across the Amazon biome and focused on a systematic review of the accomplishments and continuing gaps in the last 10 years of research related to bats in Brazilian Amazonia, which constitutes approximately 60% of the Amazon basin. The analysis of 3771 occurrence records, belonging to 184 bat species and distributed in 104 localities across all Amazonian biogeographic subregions, bolsters the idea that the Guianas, the Eastern and the Western Amazon regions have distinct bat faunal compositions, which can be explained by evolutionary history. For the Brazilian Amazon, we confirmed records for 144 species and 63 genera, including 34 endemics. Our knowledge of bats in the Brazilian Amazon has improved, but it is highly heterogeneous, biased toward forested areas rather than other ecosystems such as Campinas, Campinaranas, and Cangas.
... Bat-mediated biocontrol services (defined as the impact of bats on the population density of pests) have proven to affect both yield quantity and quality in crops as diverse and economically relevant as cotton (e.g. Boyles et al., 2011), rice (Puig-Montserrat et al., 2015), coffee (Classen et al., 2014), grapes (Charbonnier et al., 2021) and cacao (Maas et al., 2013). Paradoxically, bats are currently under unprecedented threat from agricultural intensification (Voigt & Kingston, 2016). ...
Biocontrol services are widely recognized to provide key incentives for bat conservation. However, we have virtually no information on whether and how disruptions in bat‐mediated biocontrol services are driven by mismatches between the temporal activity patterns of insectivorous bats and insect pests.
We investigated the temporal relationship between the nightly activity patterns of the common pipistrelle bat (Pipistrellus kuhlii) and the olive fruit moth (Prays oleae). Temporal mismatches between species pairs were estimated as the time difference (expressed as a percentage of the night) at which P. kuhlii and P. oleae reached 50% of their abundance.
The study was carried out during spring, summer, and fall between 2017 and 2019 in 60 olive farms representing increasing levels of structural simplification (as a surrogate of agricultural intensification). Olive farms were classified as exhibiting high (i.e. HIGH olive farms; n = 27), intermediate (MID; n = 18), and low (LOW; n = 15) structural complexity.
Temporal mismatches between the activity levels of P. kuhlii and P. oleae varied between seasons and types of olive farms, being comparatively lower in summer than in spring and fall. Furthermore, summer was the only season in which temporal mismatches between species pairs differed between types of olive farms, with higher temporal mismatches found in LOW than in HIGH and MID olive farms.
Overall, our work demonstrates the existence of temporal mismatches between the nightly activity patterns of P. kuhlii and P. oleae. Furthermore, it demonstrates that the structural simplification of olive farms increases temporal mismatches between species pairs, particularly in summer when bat‐mediated biocontrol services are most needed.
Synthesis and applications. Future research should consider mismatches between the temporal activity patterns of insectivorous bats and insect pests. Otherwise, the actual impact of agricultural intensification on bat‐mediated biocontrol services as well as the economic impact of their loss on the agriculture industry might be underestimated. To enhance biocontrol services, we propose increasing the availability of suitable roosting and foraging sites as well as conserving areas of remnant native woodland and scattered hollow‐bearing trees.
... As native and versatile predators of nocturnal insects, bats are important vectors for pest suppression in agricultural areas and they may track populations of agricultural pests (McCracken et al. 2012;Taylor et al. 2018). Several enclosure experiments have demonstrated that the density of arthropods increases significantly when bats are absent in agroecosystems (Maas et al. 2013). In this study, through DNA metabarcoding analysis of bat diets, we identified 75 species of insects that can cause major damage to a range of agricultural production and forestry systems, including cereals (like wheat, rice, and maize), vegetables (like cabbage, potato, and pepper), fruits (like apple, peach, and pear), and forest trees (like eucalyptus and poplar). ...
Smallholder farming systems make a vital contribution to food security. However, pests pose a significant challenge to the productivity and sustainability of these agricultural systems. The need to reduce the usage of chemical pesticides in agriculture has intensified due to growing public health and environmental concerns. Retaining generalized predators to biologically control pests is commonly considered as an alternative management strategy. Bats are widely acknowledged as highly effective pest suppression agents. However, little is known about how bats contribute to pest suppression services in smallholder farming systems and how different sympatric bat species divide their use of food resources. We employed DNA metabarcoding to determine the differential prey species consumed by seven bat species in Chinese smallholder farming systems to clarify pest suppression services and dietary niche differentiation. We detected 19 orders of arthropods, among which mosquitos (Diptera), moths (Lepidoptera), and beetles (Coleoptera) were the most predominant prey items. We also documented 75 major pests consumed by bats that can potentially damage agricultural areas or spread diseases. Moreover, there was a significant differentiation among the seven sympatric bat species. Finally, Spearman correlation analysis shows that morphological and echolocation traits may explain dietary niche differentiation. Our results suggest that bats play a critical role in pest suppression services in smallholder farming systems and further prove that the dietary niche was significant differentiation among bat species. These results implied that landscape heterogeneity in smallholder farming systems may increase arthropod diversity, in turn increase biological pest control by bats. Thus, our results also highlight the importance of conserving bat populations and their crucial ecosystem services in integrated pest management (IPM), which has significant implications for the potential protection of food security and human health.
... Birds were directly responsible for an increase in coffee yield by predating the coffee berry borer (Hypothenemus hampei) (Karp et al. 2013). There are many more studies linked the success of birds as predators of insect pests in agricultural landscapes with native proximity (Maas et al. 2013;Philpott et al. 2009). Birds use agroforests as sites for breeding, hibernation, and roosting (Fuller et al. 2001). ...
Traditional agriculture relies on ecosystem services for sustainable food production and is also identified as a climate-smart approach. The present study analyses the agroforests associated with the rice farming system of three different agricultural practices for biodiversity richness by comparing two parameters: plants and birds. Out of the nine study sites, three sites were traditional farms maintained by Kurichiya tribal communities, three were natural farms, and the other three farms were modern. A total of 45 families, 104 genera, 128 species of plants, and 101 bird species belonged to 48 families, and 17 orders were identified from the study sites. The sample-size-based rarefaction and extrapolation (R/E) method was adopted to identify estimated biodiversity indices. Renyi profile was used to understand the native tree diversity profile of the selected sites. The result of this study indicates that bird diversity is positively correlated with native tree diversity and NDVI of May and October. Conserving more native trees in the farmland could be one of the reasons for the sustainable agriculture system of the Kurichiya tribal community as it attracts more bird species and contributes to the biological control of pests. Thus, the conservation of native tree species in the agroforest of rice-based agroecosystems will contribute to the sustainable agriculture system.
... Preventing outbreaks of pathogens by monitoring these mammals should be a priority for public policies in Brazil, as they are cost effective and can save human lives (Winck et al., 2022). Regulatory species that deliver pest and disease control service, on the other hand, contribute to increasing crop yields and food security, reducing the need for pesticides, improving ecosystem integrity and human health (Maas et al., 2013;Wanger et al., 2014). ...
For the 701 mammals that occur in Brazil (ca. 13% of extant mammals worldwide), we attributed ES to each deliverer one based on their functional traits, known trophic interactions, expert knowledge, and by overlaying IUCN’s distribution maps of the species. The ES term encompasses both ecosystem processes and services, offering a broader perspective that enables us to investigate the potential benefits of mammals to people. We assumed that species that are currently listed as threatened in the IUCN most likely lost their ES role. We found that 82% of Brazilian mammals (575 spp.) deliver at least one of the 11 ES identified. Cultural services were associated with the greatest number of deliverer species, while carrion control, ecosystem engineering, and rodent control were delivered by fewer species. Although only 24% of the species analyzed here are endemic to Brazil, 75% of them deliver at least one ES. The ES they delivered are also disproportionately at risk, as 57% of the species considered to have lost their ES role are endemic. Ecosystem service provision does not merely mirror the spatial patterns of mammal richness in general, as we identified hotspots for each service across Brazil, including its seascapes. Our comprehensive assessment provides a clear overview of the myriad of services delivered by Brazilian mammals, including taxonomic and spatial explicit information for each service. Identifying and mapping species and their services can contribute to more effective management and conservation programs focused on optimizing the supply of ES and conserving biodiversity.
... Although not widely adopted for a number of reasons, including time and cost effectiveness (Savary et al. 2012;Lou et al. 2013), the control of agricultural pests by augmenting natural enemy populations of parasitoids (Sharma et al. 2019), birds (Long et al. 2013;Karp and Daily 2014;Maas et al. 2016), and fish (Halwart et al. 2012) has been used for many decades. Only in the last decade and a half, however, have insectivorous bats been widely recognised for their role in insect control (Cleveland et al. 2006;Boyles et al. 2011;Maas et al. 2013). ...
Context
Rice, India’s most widely grown crop, suffers substantial and increasing yield loss to insect pests. Insectivorous bats are known suppressors of insect pests, providing significant economic value to agricultural systems worldwide, yet their ecology in Indian agricultural landscapes is poorly understood.
Objectives
We assess the influence of key biotic and abiotic factors on the activity of insectivorous bats over the growing season and within a night in a rice cultivation landscape.
Methods
Passive acoustic recorders were used to track bat activity in a rice field in the Sonitpur district of Assam, India. We used generalised linear mixed models to analyse the effect of temperature, insect activity, and moonlight intensity on the activity of six bat sonotypes. We also used a multimodal analysis to describe the within-night activity patterns of these sonotypes.
Results
Minimum nightly temperature and moonlight intensity had a positive and negative influence, respectively, on the activity of six bat sonotypes, while the activity of four bat sonotypes increased with insect activity. Within-night activity showed one of two patterns: three sonotypes displayed a dusk peak in activity, while the three other sonotypes were active through the night.
Conclusion
The potential to maximise natural pest control in agricultural landscapes can only be realised through understanding the ecology of natural enemies in these landscapes. Our findings suggest that bats in rice fields are tracking insects over a season and within a night, pointing to a valuable ecosystem service in Indian agriculture that is yet to be quantified.
... In particular, they are of great importance for the suppression of insect populations, like agricultural pests (Boyles et al., 2011;Maas et al., 2016;Librán-Embid et al., 2017), and for assisting in the vital process of renewing disturbed or damaged areas of natural forest through seed dispersion (van Toor et al., 2019). Studies conducted in Asia (Maas et al., 2013) and South America (Vansynghel et al., 2022) showed that pest suppression by bats and birds increased cocoa yield independently of shade tree cover by 31 % and 114 %, respectively. However, in the only study to date focusing on the role of bats in African cocoa (Curtis et al., 2018), in the only study to date focusing on the role of bats in African cocoa showed that bats and birds can save Cameroonian farmers an average of $478 per ha per year through pest consumption when shade tree cover is maintained at high levels. ...
... Insectivorous bats have been identified as generalist pest predators (Cohen et al. 2020;Ramírez-Fráncel et al. 2022) and impose strong suppression on pests in some agroecosystems (Maas et al. 2013;Maine and Boyles 2015;Wanger et al. 2014;Russo et al. 2018). An echolocating insectivorous bat can consume pests equivalent to >25% their own body weight per night (Kunz, 1974). ...
... In addition, AFS serve as corridors for mammals (Williams-Guillén et al. 2006) and contribute to improve connectivity at the landscape scale (Asare et al. 2014;Schroth and Harvey 2007). The canopy structure of AFS promotes the regulation of microclimate (Siles et al. 2010;Jiménez-Pérez et al. 2019) and the presence of organisms that facilitate nutrient cycling, pollination and pest control, which can increase productivity at the farm level (Maas et al. 2013). For this reason, it has been suggested that implementing AFS in agricultural land around protected areas can help to conserve biodiversity more effectively (Bhagwat et al. 2008;Swallow et al. 2006). ...
Agroforestry systems (AFS) are important for biodiversity conservation outside protected areas. The presence of shade trees in AFS form structurally complex habitats that provide food for many species. Habitat complexity is considered an essential biodiversity variable and its characterization is now possible using remote sensing techniques, including 3D point clouds derived from images obtained with unmanned aerial vehicles (UAVs). However, studies evaluating the relationship between canopy structure and variables derived from 3D clouds are rare for AFS, especially for the tropical Andes. Here, we show how six important variables of canopy structure can be predicted across a canopy structure gradient from AFS with cacao and coffee to a natural forest using characteristics extracted from the 3D point clouds and multiple linear regression. For leaf area index the best model obtained an R² of 0.82 with a relative RMSE = 24%, for canopy cover an R² of 0.81 and relative RMSE = 13%, for above-ground biomass an R² of 0.81 and relative RMSE = 10%, the density of shade trees was predicted with an R² of 0.66 and relative RMSE = 34%, the mean height and the standard deviation of height in the canopy obtained an R² of 0.82 and 0.79 respectively, and relative RMSE of 18% for both. The approach presented in this study allows an accurate characterization of the canopy structure of AFS using UAVs, which can be useful for assessing above-ground biomass and biodiversity in tropical agricultural landscapes to monitor sustainable management practices and derive payments for ecosystem services.
... Marsupials are not an exception for this general pattern, since studies investigating food utilization by several species showed that these factors can be important to understand not only the general patterns of the species diet but also how it varies spatially and temporally (Camargo et al. 2014a;Camargo et al. 2019;Melo et al. 2019). Identifying such patterns can be relevant for better comprehension of several distinct aspects of food niche dynamics, competition, and evolution (Svanbäck and Bolnick 2005;Sommerville et al. 2011;Lessa 2012;Camargo et al. 2014b;Costa-Pereira et al. 2017;Carvalho et al. 2019) or else for providing knowledge for conservation purposes (e.g., Maas et al. 2013). ...
... Scattered trees can also serve as useful indicator structures of ecosystem function (Hunter et al., 2017;Lindenmayer, Margules, & Botkin, 2000;Tews et al., 2004). Conserving trees in disturbed landscapes can maintain high levels of biodiversity, which may also facilitate vital ecological services (e.g., pollination and seed dispersal; Herrera & García, 2009) that can ultimately provide numerous socio-economic benefits (e.g., arthropod pest control by birds and bats in agricultural land; Maas, Clough, & Tscharntke, 2013) 14 . ...
The scope of the Handbook is to provide support for the capacity building programme from the SaveGREEN project and to represent a basis for policy work for advocating the improvement of management practices in corridor areas
... When birds were excluded from the cereal crops, arthropod natural enemy abundance was greater and aphid densities were lower (Grass et al., 2017). Overall, from the literature on the net effects of wild birds on arthropod communities in agroecosystems we can glean that wild birds typically exert top-down forces on arthropod communities (Maas et al., 2013;Díaz-Siefer et al., 2021). Thus, it can be expected that chickens and other insect-eating poultry would interact with arthropod communities in a similar way. ...
As consumer demand and grower interest for pasture-raised poultry grow, more research is needed to understand the ecological consequences of the integration of pasture-raised poultry on agroecosystems. Poultry could have profound and complex net effects on arthropod communities given their high density per area, broad omnivory, and high manure deposition. Further, some studies suggest poultry may aid in the suppression of agricultural pests in integrated systems. Yet, unlike wild birds, pasture-raised poultry have received little attention in the field of agroecological net effects. Across 2 years, we examined how an absence (control- cover crop only), low- [9.51 m ² (102.4 ft. ² ) of pasture per broiler] and high-densities [4.76 m ² (51.2 ft. ² ) of pasture per broiler] of broilers impacted cover crop biomass, ground-dwelling arthropods, and plant-dwelling arthropods in a rotationally grazed mixed-cover crop system. High- and low-density poultry treatments had 7.8-fold and 3.5-fold less cover crop biomass compared to the control treatment after 1–3 days of access, respectively. Despite the depletion of cover crops, there were substantial positive effects on ground-dwelling arthropods. Most striking was the impact on house fly larvae where high-density poultry treatments had ~1,432-fold more house fly larvae relative to the control treatments. Dung beetle, spider, and rove beetle mean relative abundances increased 47-, 2.4-, and 3.5-fold, respectively, from the control treatment to the high-density poultry treatment. In contrast, the mean relative abundances of plant-dwelling arthropod orders Coleoptera, Hemiptera, and Hymenoptera were 4-, 5-, and 3.6-fold higher, respectively, in the control treatment relative to the high-density poultry treatment. Overall, these results suggest that pasture-raised poultry may promote the abundance of ground-dwelling arthropods through bottom-up mechanisms by depositing fecal material. However, poultry decreased the abundance of plant-dwelling arthropods, likely by destroying their habitat and food resources (via consumption and trampling of cover crop) and direct consumption of arthropods. While the integration of poultry into crop rotations is thought to benefit crop yield through nutrient deposition in the form of manure, this study suggests it may also stimulate the soil and ground-foraging arthropod food webs. This study is the first to evaluate the impacts of pastured poultry to arthropod communities in a mixed-cover crop system.
Hipposideros spp . are insectivorous bats and karst cave dwellers. This study aimed to study the roosting ecology, reproduction, and population fluctuations of three species H. diadema , H. larvatus , and H. ater in Gunung Sewu Karst region, Indonesia. Age and reproductive status of individuals were identified and analyzed using a combination of forearm length (FA) and body mass grades (W). Multiple regression analysis was used to determine the correlation between population size, rainfall and population structure based on FA, reproductive status, and W. Crude birth rate (CBR) and general fertility rate (GFR) were used to determine the population’s birth rate and female fertility. The results showed that the population of the three Hipposideros species were quite stable over the year with a peak in January which classified them as monoestrous, with mating, pregnancy, and lactation occurring once a year with no delay between mating and pregnancy. Pregnancy lasted 8–12 weeks and lactation 4–5 weeks. The population structure of the three species tended to be stable over the year. The CBR and GFR values can be used for rapid assessment guidelines in an area.
Bordoibam-Bilmukh is a small wetland located at the boundary of the Dhemaji and Lakhimpur districts of Assam, India that provides shelter and breeding ground to many resident and migratory birds. A survey was conducted between October 2022 and March 2024 on the avian diversity of Bordoibam-Bilmukh Bird Sanctuary. A total of 47 bird species under 16 orders and 29 families were recorded during the survey. Order Passeriformes, recorded with the highest number of avian species (15). Among the families, the highest number of species (5) was recorded under Ardeidae. Out of all the species recorded, three species, viz., Brown Shrike, Citrine Wagtail, and White Wagtail were winter migratory; one species, the Lesser Kestrel, was summer migratory, and the remaining 43 were resident species. Besides, two species, viz., Lesser Adjutant and Greater Adjutant are listed as ‘Near Threatened’ species on the IUCN Red List. Comparing the avian diversity from 1997 to 2024, a decline in the number of avian species from 167 (as per the 1997 record) to 47 (as per the present study) has been observed in the sanctuary. Various anthropogenic activities such as habitat destruction and disturbance, hunting of birds, are the major causes of the decline of avian diversity. For future species diversity restoration in the sanctuary, these negative anthropogenic activities should be addressed immediately for conservation strategies.
While many herbicide active substances have been banned and weed infestation is a major threat to crop productivity, it is still unknown to what extent natural weed control provided by seed predators can help farmers manage weed communities. We aim to quantify the contribution of seed predators to crop productivity through weed control and to evaluate whether the magnitude of their influence depends on farming systems such as conservation agriculture. We set up 112 seed predator-exclusion cages in 28 cereal fields in France (14 pairs of conservation and conventional agriculture fields), surveyed weed emergence and biomass, measured crop yield and sampled the main seed predators: carabid beetles and rodents. We found that seed predators’ activity reduces the yield loss due to weeds by 20%. By extrapolation, it represents an economic gain of 285€/ha. However, the yield loss remains at 60% below the maximum crop yield potential reached in the absence of weeds. Moreover, conservation agriculture enhances weed control, but this does not translate into increased crop yield. This study demonstrates the tangible importance of considering seed predators for weed control but highlights the need to combine this approach with weed control practices or to substantially redesign cropping systems to enhance the beneficial effects of biodiversity on crop productivity.
Significance statement
Although weed biomass is the main driver of decreasing the crop productivity worldwide and the use of herbicides is massively disparaged, we have not yet quantified the role played by on-farm biodiversity to control weeds. Using an experimental design set up in 28 commercial cereal fields in France, we showed that weed seed predators reduce crop yield loss due to weeds by 20%. By extrapolation, it represents an economic gain of 285€/ha. However, in the absence of any other weed control practices, the yield loss remains at 60% below the maximum crop yield potential reached in the absence of weeds. This study demonstrates the quantitative importance of considering seed predators to design pesticide-free systems.
Arthropods are crucial for sustaining global cacao cultivation, contributing to diverse ecological functions within the cacao agroecosystem. Despite their importance, there’s a lack of comprehensive documentation on factors influencing arthropod presence, ecosystem services, impact, management, and conservation across cacao cultivation systems. To bridge this gap, our study aimed to consolidate existing knowledge by systematically mapping global scientific articles on arthropods associated with cacao cultivation. Using advanced text mining and structural topic modeling, we identified eight thematic categories in 552 articles, with 69.6% published between 2000 and 2023. Geographically, studies were concentrated in America (38.2%), Africa (34.6%), and Asia (20.8%). Publications showed a surge across most topics, providing updated insights into their distribution. Research in America focused on beetles, parasitoid hymenopterans, ants, pollinating dipterans, and arachnids. Conversely, substantial publications addressed pest arthropods, including hemipterans in Africa, the Cocoa Pod Borer in Asia, and other pests in America and Africa. Through our systematic analysis, we uncovered key topics shedding light on arthropod biology and ecological interactions, highlighting the importance of agroforestry systems for conserving diversity and promoting ecosystem services like pollination and biological control. The study outlines research trends and gaps within each topic, serving as a valuable resource for professionals and policymakers, facilitating further investigations into arthropods in the cacao agroecosystem.
Cacao is the most important agricultural product in the southern region of Bahia state, Brazil, with 70% of its production occurring under the traditional agroforestry where cacao is mostly shaded by native trees. This traditional system allows to reconcile the production with the maintenance of the portion of original biodiversity. However, increased deforestation and intensified agroforestry management aimed at boosting productivity may impact the diversity of native species and the services they provide. In the context, our aim was to disentangle the role of landscape forest cover and the local vegetation complexity on predation of caterpillars and herbivory of cacao plants located in agroforestry systems. The study was conducted at 18 cacao agroforest sites in southern Bahia located in landscapes with different amounts of forest cover. We assessed predation rate using dummy caterpillars, sampled understory birds and arthropods and collected leaves of cacao trees to analyze damage by herbivory. We also measured shading and abundance of cacao trees in each agroforestry. Predation pressure on dummy caterpillars was positively influenced by the abundance of total predators and the level of landscape forest cover and negatively by the number of cacao trees. Even so, we found no evidence that landscape, local features or the actual invertebrate assemblages (predators or herbivores) influenced the cacao leaf damage. The findings highlight the multifaceted interactions between ecological factors, predation pressure, and leaf damage within cacao agroforestry systems.
Land-use systems have a significant impact on environmental, economic, and societal issues worldwide. This study uses R's Biblioshiny package to critically examine an extensive bibliographic database of 1814 publications on global land use systems development and sustainability (GLUSDS) from the Web of Science (WoS). Findings indicate that the scientific productivity of GLUSDS has been increasing between 2004 and 2023. The five most influential sources, constituting ‘Sustainability’, ‘Land Use Policy’, ‘Land’, ‘Science of the Total Environment’ and ‘Ecological Indicators’ produce and disseminate information that drives policy responses, innovations and future research perspectives. Similarly, the most cited papers demonstrate the complexity and encompassing nature of land use systems development and sustainability. There was a low (high) level of cooperation between (among) the leading scholars in the field. Compared to emerging nations, industrialised nations such as China, the United States, the United Kingdom, and Germany have a far greater impact on land use science. Current research trends demonstrate the utilization of ‘digital technologies (DTs)’ through the application of Geographic Information Systems (GIS) and integrated remote sensing techniques, Geo-detectors, regression models, artificial intelligence, as well as social and economic models to comprehensively identify, monitor and advance knowledge in land use science, management and sustainability. Thus, we support initiatives like 'Citizen Science' that promote the adoption of cutting-edge theories, methods, instruments, and procedures that support the sustainable use of lands and other natural resources. Limited scientific investments and productivity from industrialized and emerging nations call for further studies in land system science and management.
the aim of this paper is to provide an economic estimate of three ecosystem services (water used for irrigation, pollination and natural pest control using birds and bats) under different adaptation scenarios for the agricultural production in Extremadura
Balancing biodiversity conservation and agricultural productivity is commonly regarded as a trade-off, but such analyses overlook ecosystem services that functional biodiverse communities provide in agroecosystems, and the possibility that win-win strategies may exist. We developed a dynamic mechanistic community model of the bird-insect food web associated with African cocoa agroforestry, structurally informed by metabarcoding data on bird diets, and fitted to trapping data on species abundances. We used the model to predict equilibrium community composition under varying intensities of shade management and pesticide use. Our results indicate that low-intensity farming favours forest bird species, and potential pollinator abundance, with no increase in pest biomass. Furthermore, using simulations of pesticide application, we found that pesticides do not effectively reduce pest biomass, and result in forest bird extinction. Our mechanistic framework combines the influence of management and the direct and indirect effects of species' interactions, and demonstrates that low intensity agriculture may provide a win-win for biodiversity and ecosystem services.
Urbanization is a major process of land-use change that results in transformation of natural habitats and landscape structure due to increasing sealed areas, higher density of buildings, and reduced green areas. Urbanization has been associated with the loss of biodiversity due to habitat loss and fragmentation; therefore, conserving biodiversity in urban areas is a pressing challenge. Although different taxonomic groups are negatively affected by urbanization, little is known about the effects of urbanization on insectivorous bats. In addition, the influence of different urban green areas on bat activity and species richness has not been explored. The aim of this study was to assess whether landscape structure surrounding urban green areas influenced bat activity and species richness in total, as well as to assess differences in the response between functional groups. During summer 2014, I acoustically surveyed bats at 180 points distributed in nine types of green areas in Vienna and quantified landscape structure at 0.5 km and 1 km radius-buffer areas. My results showed that bats responded to landscape structure in diverse ways depending on the scale of analysis. Therefore, response assessments of a high mobile order like bats on land-use changes has to be done at least at two scales, because the influence of landscape characteristics changes with the scale of analysis. Although my study clearly showed differences in the response of bats based on morphological and behavioral traits of bat species, certain landscape characteristics seem to be important for most groups and management efforts need to take these findings into consideration. Bat activity of most functional groups was favored by size and shape of green areas, the latter also increased species richness of most functional groups. Also, heterogeneous landscape with high diversity and high intermixture of land-use strongly influenced species richness and bat activity of many analyzed bat groups. And, industrial areas had negative effects on most bat groups and even on the occurrence of the urban adapted Pipistrellus pipistrellus. Thus, large and simply shaped green areas as well as a diverse and intermixed landscape are important to mitigate the impact of urbanization on bats. Also, the negative effects of industrial areas on most bat groups need to be considered especially when authorizing new industrial areas in the outer districts of Vienna. Additionally, my assessment of the influence of building heights on the bat assemblage gave first indications that building heights affected bat activity and species richness. In this context, it is important for bats to ensure the possibility to exploit the urban landscape with low energy costs by maintaining intermixed building heights within highly urbanized areas.
The brown honeyeater ( Lichmera indistincta ) is a common bird species in Australia and is a pollinator of many native plant species but there are no records demonstrating evidence of effective pollination by honeyeaters in commercial cropping systems.
We observed L. indistincta visiting rabbiteye blueberry flowers at a commercial berry orchard on the Mid North Coast of New South Wales and evaluated their capacity to transfer pollen. We did this by bagging flowers to prevent visitation prior to anthesis; after anthesis, we unbagged the flowers and waited for L. indistincta visits. After a single visit, we collected the stigma and mounted it on a slide to evaluate stigmatic pollen load.
We observed the birds visiting blueberry flowers and foraging on nectar. We also found that L. indistincta deposited similar amounts of pollen to other common insect pollinator species, such as honeybees and stingless bees. As the commercial berry orchard blocks are surrounded by diverse remnant vegetation, we hypothesize that the vegetation is likely providing habitat for these birds.
Our results indicate that berry growers with management practices that protect and support remnant vegetation surrounding blueberry orchard blocks may benefit from higher blueberry pollination services by supporting diverse pollinators within fields.
We examined the indirect effects of insectivorous birds on plant growth through consumption of leaf-chewing insects in a Missouri Ozark deciduous forest. Over a period of 2 yr, we compared insect numbers, leaf damage, and resultant plant growth for control saplings of white oak (Quercus alba), vs. saplings that we caged to limit access by insectivorous birds but not herbivorous insects. In a third treatment, we sprayed insecticide on young white oak trees to determine the impact of the insect herbivores on plant growth in the presence of birds. The total number of insects encountered on plants inside of cages was twice that on control plants for both years. Insecticide spray reduced herbivore numbers substantially but did not eliminate them. As a result of the treatments, cage plants suffered 25% leaf area loss, control plants 13%, and spray plants 6% at the end of the first season (34, 24, and 9%, respectively, for the 2nd yr). As a result of the differences in damage, cage plants produced one-third less total aboveground biomass compared to insecticide-treated plants, with control plants producing intermediate value. Differences in biomass production were due mainly to decreased leaf biomass, which in turn was associated with decreased leaf size in subsequent years as a result to high damage during the previous year. This is the first terrestrial ecosystem study to demonstrate a significant impact of insectivorous birds on plant growth. Our results suggest that over the long term observed declines in North American populations of insectivorous birds may reduce forest productivity because of potentially higher numbers of leaf-chewing insects and the concomitant negative effect on plant growth.
T op-down limitation of herbivores is an im-portant ecosystem service that facilitates agricultural production (1). Several experi-ments in natural and managed ecosystems demon-strate the importance of avian predators in arthropod control (2). Although insectivorous bats are ex-pected to have major impacts on arthropods (3), few studies have quantified the effects of bats on standing crops of arthropods. Because all previ-ous exclosure-based studies of avian insectivory have left exclosures up during the night, it is possible that a proportion of predation attributed to birds may represent predation by foliage-gleaning bats. Here, we report an exclosure experiment conducted in a Mexican coffee agroforest, in which we directly measured the impact of pre-dation by foliage-gleaning birds and bats on ar-thropods found on coffee plants. We used exclosures made of agricultural net-ting erected around individual coffee plants in Finca Irlanda, an organic shade coffee plantation harboring abundant populations of ≥120 bird species and ≥45 bat species. We established 22 blocks of four treatments: birds-only excluded (exclosure netting in place only during the day), bats-only excluded (netting in place only during the night), both excluded (netting in place day and night), and control (no netting). We visually censused noncolonial arthropods (primarily insects, but also spiders, harvestmen, and mites) on all plants at the beginning of the experiments, every 2 weeks thereafter, and at the end of the experiment. We conducted the experiment for a 7-week period beginning January 2007 (dry season) and for an 8-week period beginning June 2007 (wet season). Exclusion of birds and bats resulted in sig-nificant increases in total arthropods on experi-mental plants, although a significant amount of variation was also explained by foliage biomass and initial arthropod density (table S1). On average, total arthropod densities on plants from which both predators were excluded were 46% higher than those observed on control plants. There was a clear seasonal effect with regard to bats: Although bats did not have significant ef-fects on arthropod densities in the dry season, their impacts were highly significant in the wet season, with an 84% increase in arthropod den-sity in bat-only exclosures, exceeding the effects of birds (Fig. 1). In neither season was there a significant interaction between bats and birds, indicating an additive effect. Regardless of sea-son, arthropod densities increased the most on plants from which both birds and bats were ex-cluded (Fig. 1). These seasonal and additive pat-terns held for various arthropod taxa (table S2), although only birds significantly reduced spiders. Although predator exclusions resulted in increased arthropod density, no significant differences were seen between treatments in the prevalence or the intensity of leaf damage. At our site, bats were as important as birds in regulating insect populations across the course of the year. We suspect that increased impacts of birds in the dry season may result from an influx of insectivorous overwintering migrants from North America (4). We have no data on the ab-solute density of bats versus birds; however, at our site the capture rates (and presumably abundance) and reproductive activity of bats increased during the wet season. Bats' relatively higher surface area may result in greater heat loss and concom-itantly higher energy requirements (5), and reproduction increases females' energetic needs; thus, increased bat abundance and reproduction in the wet season may result in an increased impact of bat predation on understory arthropods. Our results are consistent with arguments that functional diversity is central to the main-tenance of ecosystem services (6). In this case, the presence of these two vertebrate taxa main-tains a functional difference that enhances the efficacy of arthropod reduction. Previous exclo-sure studies have not differentiated between diurnal and nocturnal predators, attributing ob-served changes to birds. We suggest that these studies of the impacts of "bird" predation may have underestimated the importance of bats in limiting insects. Bat pop-ulations are declining worldwide (7), but mon-itoring programs and conservation plans for bats lag far behind those for birds. Declin-ing bat populations may compromise critical eco-system services, making an improved understanding of their conservation status vital.
Cited By (since 1996):63, Export Date: 26 November 2013, Source: Scopus
Although most bird species avoid agricultural areas, nearly a third of all birds regularly to occasionally use such habitats, often providing important ecosystem services like pest control, pollination, and seed dispersal. Combining literature review with large-scale analyses of the ecological characteristics of the world's birds, I compared 6100 tropical bird species that prefer forests, agricultural areas or both, with respect to body mass, diet, range and population size, frequency, conservation status, habitat and resource specialization. Compared to primary forests, species richness of large frugivorous and insectivorous birds (especially terrestrial and understorey species) often declines in agroforests. In contrast, nectarivores, small-to-medium insectivores (especially migrants and canopy species), omnivores, and sometimes granivores and small frugivores do better, frequently by tracking seasonal resources. However, changes in guild species numbers do not necessarily translate to changes in relative abundance, biomass or function, and more studies are needed to quantify these important measures. These findings indicate that the replacement of forests and agroforests with simplified agricultural systems can result in shifts towards less specialized bird communities with altered proportions of functional groups. These shifts can reduce avian ecosystem function and affect the ecosystem services provided by birds in agroforests and other agricultural landscapes.
Both birds and bats are important insect predators in tropical systems. However, the relative influence of birds and bats on insect populations and their indirect effects on leaf damage have not previously been investigated in tropical forest restoration sites. Leaf damage by herbivorous insects can negatively affect the growth and survival of tropical plants and thus can influence the success of tropical forest restoration efforts. We used an exclosure experiment to examine the top-down effects of birds and bats on insects and leaf damage in a large-scale forest restoration experiment. Given the potential influence of tree planting design on bird and bat abundances, we also investigated planting design effects on bird and bat insectivory and leaf damage. The experiment included two planting treatment plots: islands, where trees were planted in patches, and plantations, where trees were planted in rows to create continuous cover. In both types of plots, insect biomass was highest on tree branches where both birds and bats were excluded from foraging and lowest on branches without exclosures where both birds and bats were present. In the island plots, birds and bats had approximately equal impacts on insect populations, while in plantations bats appeared to have a slightly stronger effect on insects than did birds. In plantations, the levels of leaf damage were higher on branches where birds and bats were excluded than on branches where both had access. In island plots, no significant differences in leaf damage were found between exclosure treatments although potential patterns were in the same direction as in the plantations. Our results suggest that both birds and bats play important roles as top predators in restoration systems by reducing herbivorous insects and their damage to planted trees. Tropical restoration projects should include efforts to attract and provide suitable habitat for birds and bats, given their demonstrated ecological importance.
Seem to favour the idea that rare species are common elsewhere e.g. on a different plant species.
ABSTRACT Although nest predation is often the single largest source of mortality in avian populations, manipulative studies to determine predator impacts on nest survival are rare, particularly studies that examine impacts of mid-size mammalian predators (hereafter, mesopredators) on nest survival of shrub-nesting birds. We quantified nest survival and identified nest predators of shrub-nesting songbirds within 4 large (approx. 40-ha) exclosures and 4 control sites within a longleaf pine (Pinus palustris) ecosystem. During 2003–2006, we located and monitored 535 shrub nests (222 with videography) for 4,804 nest-days to quantify daily nest survival and document predation events. We found no support for a treatment effect, suggesting mesopredators had little impact on daily nest survival (0.9303 in controls and 0.9260 in exclosures) of shrub-nesting songbirds. For the 5 most commonly monitored species, daily nest survival within species was constant. Our analysis suggested that shrub nests were most vulnerable during the nestling stage and presence of cameras on nests increased survival with the increase in survival being more pronounced during the incubation stage. We filmed 107 nest predation events, identifying predators at 88 nests. Of these 88 nests, snakes caused 33%, red imported fire ants (hereafter fire ants, Solenopsis invicta) 28%, raptors 17%, corvids 8%, mesopredators 6%, and small mammals 8% of nest predations. Cause-specific nest predation in controls and exclosures did not differ from expectation, providing evidence that compensatory predation did not occur. Nest predators differed from expectation with regard to nest stage; fire ants and raptors only depredated nests during the nestling stage. Presence of cameras had no effect on nest abandonment. Fire ants were the most prevalent nest predator, and nest predation by fire ants was only observed on nestlings, potentially reducing likelihood of renesting. Magnitude and timing of fire ant predation suggests that fire ants may be the most influential nest predator of shrub-nesting birds within the longleaf pine ecosystem. Our data suggest that controlling mesopredators will have no effect on nest success of shrub-nesting birds within longleaf pine forests.
Southeast Asia is a region of conservation concern due to heavy losses of its native habitats. In this overview, we highlight
the conservation importance of Southeast Asia by comparing its degree of species endemism and endangerment, and its rate of
deforestation with other tropical regions (i.e., Meso-America, South America, and Sub-Saharan Africa). Southeast Asia contains
the highest mean proportion of country-endemic bird (9%) and mammal species (11%). This region also has the highest proportion
of threatened vascular plant, reptile, bird, and mammal species. Furthermore, not only is Southeast Asia’s annual deforestation
rate the highest in the tropics, but it has also increased between the periods 1990–2000 and 2000–2005. This could result
in projected losses of 13–85% of biodiversity in the region by 2100. Secondary habitat restoration, at least in certain countries,
would allow for some amelioration of biodiversity loss and thus potentially lower the currently predicted extinction rates.
Nonetheless, urgent conservation actions are needed. Conservation initiatives should include public education, sustaining
livelihoods, and ways to enhance the sustainability of agriculture and increase the capacity of conservation institutions.
Furthermore, these actions should be country-specific and not ignore areas heavily populated by humans, as they can also harbour
high numbers of threatened species. We urge that cooperative conservation initiatives be undertaken and support (e.g., capacity-building)
be given by more developed countries in the region and beyond.
Tropical landscapes are dominated by agroecosystems, but the potential value of agroecosystems for the survival of species is often overlooked. In agroecosystems, species conservation is especially important when functional groups such as predators are affected. In Central Sulawesi, we sampled arthropods on cocoa in a gradient of land-use intensity from extensively used forest gardens to intensively used agroforestry systems. The abundance and diversity of all arthropods did not correlate with land-use intensity, so human impact was not followed by high species losses. However, the number of species and abundance of the phytophagous arthropods increased and that of the entomophagous arthropods decreased with land-use intensity. The reduced predator–prey ratio in intensified systems can be related to their reduced species richness of shade trees and the changed microclimate (increased temperature, decreased humidity and canopy cover). In conclusion, transformation of traditional into intensified agroforestry systems had a great impact on arthropod community structure on cocoa. Since predator–prey ratios decreased with increasing land-use intensity, local farmers should have least pest problems in the traditionally diversified agroforestry systems.
Top-down effects of predators can have important consequences for ecosystems. Insectivorous birds frequently have strong predation effects on herbivores and other arthropods, as well as indirect effects on herbivores' host plants. Diet studies have shown that birds in temperate ecosystems consume arthropods in winter as well as in summer, but experimental studies of bird predation effects have not attempted to quantitatively separate winter predation impacts from those in summer. To understand if winter foraging by insectivorous birds has consequences for arthropods or plants, we performed a meta-analysis of published bird exclusion studies in temperate forest and shrubland habitats. We categorized 85 studies from 41 publications by whether birds were excluded year-round or only in summer, and analyzed arthropod and plant response variables. We also performed a manipulative field experiment in which we used a factorial design to exclude birds from Quercus velutina Lam. saplings in winter and summer, and censused arthropods and herbivore damage in the following growing season. In the meta-analysis, birds had stronger negative effects on herbivores in studies that included winter exclusion, and this effect was not due to study duration. However, this greater predation effect did not translate to a greater impact on plant damage or growth. In the field experiment, winter exclusion did not influence herbivore abundance or their impacts on plants. We have shown that winter feeding by temperate insectivorous birds can have important consequences for insect herbivore populations, but the strength of these effects may vary considerably among ecosystems. A full understanding of the ecological roles of insectivorous birds will require explicit consideration of their foraging in the non-growing season, and we make recommendations for how future studies can address this.
Effects of plant traits on herbivore-carnivore interactions are well documented in component communities but are not well understood at the level of large, complex communities. We report on a 2-year field experiment testing mechanisms by which variation in food quality among eight temperate forest tree species alters avian suppression of an assemblage of dietary generalist caterpillars. Plant quality and bird effects varied dramatically among tree species; high-quality plants yielded herbivores of 50% greater mass than those on low-quality plants, and bird effects ranged from near 0% to 97% reductions in caterpillar density. We also find evidence for two mechanisms linking host plant quality to bird effects. If caterpillar density was statistically controlled for, birds had relatively strong effects on the herbivores of low-quality plants, as predicted by the slow-growth/high-mortality hypothesis. At the same time, caterpillar density increased with plant quality, and bird effects were density dependent. Consequently, the net effect of birds was strongest on the herbivores of high-quality plants, a dynamic we call the high-performance/high-mortality hypothesis. Host plant quality thus changes highly generalized herbivore-carnivore interactions by two complementary but opposing mechanisms. These results highlight the interrelatedness of plant-herbivore and herbivore-carnivore interactions and thus the importance of a tritrophic perspective.
In the core region of Brazilian cocoa production, shade cacao plantations (so-called
cabrucas) are important components of regional landscapes, constituting potential habitat for a
vast array of the regional biota. This research focuses on the ability of cabrucas to harbor bird and
bat species in two nearby districts – Una and Ilhe´us – with contrasting landscapes. At Una,
cabrucas represent less than 6% of the land and are surrounded by large tracts of forest, whereas at
Ilhe´us these shade plantations are the landscape’s dominant feature. Bird and bat communities
were richer in cabrucas located in Una compared to nearby forest, while cabrucas from the Ilhe´us
landscape were significantly poorer in species than nearby forest fragments. However, bird
assemblages in cabrucas were characterized by the loss of understory specialists and the increase of
more open area and generalist species, whereas forest dwellers still comprised most of the bat
species reported in cabrucas. Species richness and composition differed between the two landscapes.
Forest fragments and cabrucas from Ilhe´us harbored fewer forest-dwelling species than similar
habitats in Una. Our study shows that cabrucas support high species richness of birds and bats
from the native assemblages but are no surrogates for intact forests, since the presence and representativeness
of some forest species apparently depends on the existence of nearby forests. A
landscape dominated by cabrucas with a minor portion of native forest is unlikely to ensure longterm
conservation of many target species, particularly those of major conservation concern
We studied activity patterns and habitat use by insectivorous bats in Comoé National Park, Ivory Coast. Bat foraging activity was quantified along five transects representing three different habitat types using acoustic monitoring and captures with mist nets and harp traps. Aerial insect abundance was assessed using a light trap; in addition shrub and tree arthropods were sampled. Bat activity was significantly and positively related to insect availability and ambient temperature, whereas increased visibility of the moon had a negative influence on flight activity. Together, these factors best explained both total bat activity and activity of bats hunting in open space and edge habitats. The interaction between temperature and light intensity was the best predictor of activity by species foraging in obstacle-rich forest habitats, however, the regression model had a low predictive value. Overall, a large proportion (c. 50%) of the variation in bat activity appeared to be a consequence of transect- and/or habitat-specific influences. We found a significant non-linear relationship between the activity of QCF (quasi-constant frequency) and FM-QCF (frequency modulated - quasi-constant frequency) bats and the phase of the moon, with lowest levels of activity occurring near full moon. We interpret this lunar-phobic behaviour as a reflection of a higher predation risk during moonlit periods. For FM (steep frequency modulated) and CF (constant frequency) bats, no significant correlation was found, although there was a trend suggesting that these bats at least were not negatively affected by bright moonlight. Foraging activity of bats was positively correlated with the abundance of atympanate moths; however, no such correlation was found for tympanate moths.
Local and landscape-scale agricultural intensification is a major driver of global biodiversity loss. Controversially discussed solutions include wildlife-friendly farming or combining high-intensity farming with land-sparing for nature. Here, we integrate biodiversity and crop productivity data for smallholder cacao in Indonesia to exemplify for tropical agroforests that there is little relationship between yield and biodiversity under current management, opening substantial opportunities for wildlife-friendly management. Species richness of trees, fungi, invertebrates, and vertebrates did not decrease with yield. Moderate shade, adequate labor, and input level can be combined with a complex habitat structure to provide high biodiversity as well as high yields. Although livelihood impacts are held up as a major obstacle for wildlife-friendly farming in the tropics, our results suggest that in some situations, agroforests can be designed to optimize both biodiversity and crop production benefits without adding pressure to convert natural habitat to farmland.
Ecosystem services are the benefits obtained from the environment that increase human well-being. Economic valuation is conducted by measuring the human welfare gains or losses that result from changes in the provision of ecosystem services. Bats have long been postulated to play important roles in arthropod suppression, seed dispersal, and pollination; however, only recently have these ecosystem services begun to be thoroughly evaluated. Here, we review the available literature on the ecological and economic impact of ecosystem services provided by bats. We describe dietary preferences, foraging behaviors, adaptations, and phylogenetic histories of insectivorous, frugivorous, and nectarivorous bats worldwide in the context of their respective ecosystem services. For each trophic ensemble, we discuss the consequences of these ecological interactions on both natural and agricultural systems. Throughout this review, we highlight the research needed to fully determine the ecosystem services in question. Finally, we provide a comprehensive overview of economic valuation of ecosystem services. Unfortunately, few studies estimating the economic value of ecosystem services provided by bats have been conducted to date; however, we outline a framework that could be used in future studies to more fully address this question. Consumptive goods provided by bats, such as food and guano, are often exchanged in markets where the market price indicates an economic value. Nonmarket valuation methods can be used to estimate the economic value of nonconsumptive services, including inputs to agricultural production and recreational activities. Information on the ecological and economic value of ecosystem services provided by bats can be used to inform decisions regarding where and when to protect or restore bat populations and associated habitats, as well as to improve public perception of bats.
Apex predators have experienced catastrophic declines throughout the world as a result of human persecution and habitat loss. These collapses in top predator populations are commonly associated with dramatic increases in the abundance of smaller predators. Known as "mesopredator release," this trophic interaction has been recorded across a range of communities and ecosystems. Mesopredator outbreaks often lead to declining prey populations, sometimes destabilizing communities and driving local extinctions. We present an overview of mesopredator release and illustrate how its underlying concepts can be used to improve predator management in an increasingly fragmented world. We also examine shifts in North American carnivore ranges during the past 200 years and show that 60% of mesopredator ranges have expanded, whereas all apex predator ranges have contracted. The need to understand how best to predict and manage mesopredator release is urgentmesopredator outbreaks are causing high ecological, economic, and social costs around the world.
Studies that combine experimental manipulations with long-term data collection reveal elaborate interactions among species that affect the structure and dynamics of ecosystems. Research programs in U.S. desert shrubland and pinyon-juniper woodland have shown that (i) complex dynamics of species populations reflect interactions with other organisms and fluctuating climate; (ii) genotype x environment interactions affect responses of species to environmental change; (iii) herbivore-resistance traits of dominant plant species and impacts of "keystone" animal species cascade through the system to affect many organisms and ecosystem processes; and (iv) some environmental perturbations can cause wholesale reorganization of ecosystems because they exceed the ecological tolerances of dominant or keystone species, whereas other changes may be buffered because of the compensatory dynamics of complementary species.
Most forest birds include arthropods in their diet, sometimes specializing on arthropods that consume plant foliage. Experimental tests of whether bird predation on arthropods can reduce plant damage, however, are few and restricted to relatively low-diversity systems. Here, we describe an experimental test in a diverse tropical forest of whether birds indirectly defend foliage from arthropod herbivores. We also compare how the indirect effects of bird predation vary with different levels of foliage productivity in the canopy vs. the understory. For three Neotropical tree species, we observed that birds decreased local arthropod densities on canopy branches and reduced consequent damage to leaves. In contrast, we observed no evidence of bird-arthropod limitation on conspecific saplings in the less productive understory of the same forest. Our results support theory that predicts trophic cascades where productivity is high and suggest that birds play an important role in Neotropical communities by means of their indirect defense of some canopy tree species.
A goal among community ecologists is to predict when and where trophic cascades occur. For example, several studies have shown that forest birds can limit arthropod abundances on trees, but indirect effects of bird predation (i.e. decreased arthropod damage to trees) are not always observed and their context is not well understood. Because productivity is one factor that is expected to influence trophic cascades, we compared the extent to which birds indirectly limit herbivore damage to trees in two lowland Neotropical forests that differed in seasonality of leaf production and rainfall. We compared the effects of bird predation on local arthropod densities and on damage to foliage through a controlled experiment using bird exclosures in the canopy and understory of two forests. We found that birds decreased local arthropod densities and leaf damage in the canopy of the drier site during periods of high leaf production, but not in the wetter forest where leaf production was low and sporadic throughout the year. Birds had no effect on arthropod abundances and leaf damage in the understory where leaf production and turnover rates were low. In support of these experimental interpretations, although we observed that arthropod densities were similar at the two sites, bird densities and the rate at which birds captured arthropods were greater at the drier, seasonally productive site. The influence of top-down predation by birds in limiting herbivorous insects appears to be conditional and most important when the production and turnover of leaves are comparatively high.
Agricultural intensification has resulted in a simplification of agricultural landscapes by the expansion of agricultural land, enlargement of field size and removal of non-crop habitat. These changes are considered to be an important cause of the rapid decline in farmland biodiversity, with the remaining biodiversity concentrated in field edges and non-crop habitats. The simplification of landscape composition and the decline of biodiversity may affect the functioning of natural pest control because non-crop habitats provide requisites for a broad spectrum of natural enemies, and the exchange of natural enemies between crop and non-crop habitats is likely to be diminished in landscapes dominated by arable cropland. In this review, we test the hypothesis that natural pest control is enhanced in complex patchy landscapes with a high proportion of non-crop habitats as compared to simple large-scale landscapes with little associated non-crop habitat. In 74% and 45% of the studies reviewed, respectively, natural enemy populations were higher and pest pressure lower in complex landscapes versus simple landscapes. Landscape-driven pest suppression may result in lower crop injury, although this has rarely been documented. Enhanced natural enemy activity was associated with herbaceous habitats in 80% of the cases (e.g. fallows, field margins), and somewhat less often with wooded habitats (71%) and landscape patchiness (70%). The similar contributions of these landscape factors suggest that all are equally important in enhancing natural enemy populations. We conclude that diversified landscapes hold most potential for the conservation of biodiversity and sustaining the pest control function.
Losses of biodiversity and ecosystem functioning due to rainforest destruction and agricultural intensification are prime concerns for science and society alike. Potentially, ecosystems show nonlinear responses to land-use intensification that would open management options with limited ecological losses but satisfying economic gains. However, multidisciplinary studies to quantify ecological losses and socioeconomic tradeoffs under different management options are rare. Here, we evaluate opposing land use strategies in cacao agroforestry in Sulawesi, Indonesia, by using data on species richness of nine plant and animal taxa, six related ecosystem functions, and on socioeconomic drivers of agroforestry expansion. Expansion of cacao cultivation by 230% in the last two decades was triggered not only by economic market mechanisms, but also by rarely considered cultural factors. Transformation from near-primary forest to agroforestry had little effect on overall species richness, but reduced plant biomass and carbon storage by ≈75% and species richness of forest-using species by ≈60%. In contrast, increased land use intensity in cacao agroforestry, coupled with a reduction in shade tree cover from 80% to 40%, caused only minor quantitative changes in biodiversity and maintained high levels of ecosystem functioning while doubling farmers' net income. However, unshaded systems further increased income by ≈40%, implying that current economic incentives and cultural preferences for new intensification practices put shaded systems at risk. We conclude that low-shade agroforestry provides the best available compromise between economic forces and ecological needs. Certification schemes for shade-grown crops may provide a market-based mechanism to slow down current intensification trends.
• agricultural economics
• agroforestry management
• land use change
• plant–animal interactions
• ecosystem goods and services
Insectivorous bats have influenced the development of antipredator behavior in moths, green lacewings, crickets, and mantids;
until recently, such adaptations were unknown in katydids. Foliage-gleaning bats in Panama can use the female-attracting,
airborne calling songs of nocturnal katydids to locate prey. They also feed heavily on these insects. Katydid species sympatric
with these bats exhibit markedly reduced calling song duty cycles. Males supplement shortened songs with complex, species-specific
tremulations that generate vibrations that are inaudible to bats but reach conspecific females through a shared plant substrate.
Female katydids do not call audibly but are also preyed on in large numbers, perhaps as a result of moving toward calling
males.
As rates of deforestation continue to rise in many parts of the tropics, the international conservation community is faced with the challenge of finding approaches which can reduce deforestation and provide rural livelihoods in addition to conserving biodiversity. Much of modern-day conservation is motivated by a desire to conserve 'pristine nature' in protected areas, while there is growing recognition of the long-term human involvement in forest dynamics and of the importance of conservation outside protected areas. Agroforestry -- intentional management of shade trees with agricultural crops -- has the potential for providing habitats outside formally protected land, connecting nature reserves and alleviating resource-use pressure on conservation areas. Here we examine the role of agroforestry systems in maintaining species diversity and conclude that these systems can play an important role in biodiversity conservation in human-dominated landscapes.