Natacha P. Chacoff

National University of Tucuman | UNT · Instituto de Ecología Regional (IER)

1. The study of plant–pollinator interactions in a network context is receiving increasing attention. This approach has helped to identify several emerging network patterns such as nestedness and modularity. However, most studies are based only on qualitative information, and some ecosystems, such as deserts and tropical forests, are underrepresent...

Ecological interactions are highly dynamic in time and space. Previous studies of plant-animal mutualistic networks have shown that the occurrence of interactions varies substantially across years. We analyzed inter-annual variation of a quantitative mutualistic network, in which links are weighted by interaction frequency. The network was sampled...

Urban areas represent a spatially small impact in relation to other land-uses such as livestock and agriculture, but they undergo rapid changes. Such changes involve their size, shape, interconnectivity, and composition of natural patches. Habitat loss generated by urbanization affects the diversity and abundance of bees and other flower visitors i...

The study of mutualistic interaction networks has led to valuable insights into ecological and evolutionary processes. However, our understanding of network structure may depend upon the temporal scale at which we sample and analyze network data. To date, we lack a comprehensive assessment of the temporal scale‐dependence of network structure acros...

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield–related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance...

Pollination services are affected by landscape context, farming management and pollinator community structure, all of which impact flower visitation rates, pollen deposition and final production. We studied these processes in Argentina for highbush blueberry crops, which depend on pollinators to produce marketable yields. We studied how land cover...

Human population and cities are growing fast, with a concomitant modification of the land surface. Urbanization is driving biodiversity loss and biological homogenization, which impacts human wellbeing. In this study, we evaluated the influence of urbanization on flower visitor assemblage using an interaction network approach. We assessed the effec...

Los escarabajos estercoleros pueden influenciar la emergencia y supervivencia de plántulas. Sin embargo, la dirección y la magnitud de este efecto dependerá de los atributos funcionales de la comunidad de escarabajos estercoleros y de las condiciones ambientales dominantes. Estudiamos el rol de los escarabajos estercoleros en la dispersión de semil...

This book aims to provide information on pollination and the importance of pollinators for blueberries in South America, mainly in Argentina, Brazil and Chile. Below are to download the versions in: Portuguese: https://doi.org/10.5281/zenodo.7770381 Spanish: https://doi.org/10.5281/zenodo.7770394 English: https://doi.org/10.5281/zenodo.7770399

Identifying large-scale patterns of variation in pollinator dependence (PD) in crops is important from both basic and applied perspectives. Evidence from wild plants indicates that this variation can be structured latitudinally. Individuals from populations at high latitudes may be more selfed and less dependent on pollinators due to higher environ...

Landscapes dominated by conventional agriculture reduce and simplify natural habitats, with negative consequences for ecosystem regulating services. We examined differences in structure and composition of bee communities across biotic and abiotic gradients to investigate how these communities respond to land-use changes associated with agriculture....

Family farms can benefit from the presence of a diverse set of native pollinators and associated pollination services. In the present study we assessed the effect of flower visitor richness and visitation rate by honeybees and native insects on mandarin production (Citrus reticulata `Criolla´), in ten citrus family farms located in the Dry Chaco re...

Family farms can benefit from the presence of a diverse set of native pollinators and associated pollination services. In the present study we assessed the effect of flower visitor richness and visitation rate by honeybees and native insects on mandarin production (Citrus reticulata `Criolla´), in ten citrus family farms located in the Dry Chaco re...

Switching plant species visited by pollinators (partner flexibility) has been proposed as a behavioural mechanism able to attenuate the negative impacts of shifts in plant communities on pollination. However, it is unclear whether the magnitude of such response is generalizable or depends on the environmental context. Moreover, the ability of polli...

Generalist species are important for maintaining network structure and function. Previous studies showed that interactions between generalists persist across sites and years. However, the mechanisms for persistence across spatiotemporal scales are not clear. To address this gap, we collected data on plant–pollinator interactions throughout the flow...

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop y...

Landscapes dominated by conventional agriculture reduce and simplify natural habitats, with negative consequences for ecosystem regulating services. We examined differences in structure and composition of bee communities across biotic and abiotic gradients to investigate how these communities respond to land-use changes associated with agriculture....

Honey bee populations are declining as occurs with other pollinators. One suggested cause of this decline is the impact of pesticides. To improve bees’ health, pesticides and food sources may be monitored using sentinel hives, given that bees forage in a 2.5 km radius around the hive. We extracted 20 (twenty) bees, as well as samples of wax, honey...

Generalist species are the linchpins of networks, as they are important for maintaining network structure and function. Previous studies have shown that interactions between generalists tend to occur consistently across years and sites. However, the link between temporal and spatial interaction persistence across scales remains unclear. To address...

The complexity of natural communities is the result of interactions among species that coexist within them. Parasitic interactions are among the most common species interaction types, and analysis of parasite‐host ranges can advance understanding of how host‐parasite pairs structure community interactions across their geographic distributions. Usin...

Increasing honey demand and global coverage of pollinator-dependent crops within the context of global pollinator declines have accelerated international trade in managed bees. Bee introductions into agricultural landscapes outside their native ranges have triggered noteworthy invasions, especially of the African honey bee in the Americas and the E...

Understanding how bees use resources at a landscape scale is essential for developing meaningful management plans that sustain populations and the pollination services they provide. Bumblebees are important pollinators for many wild and cultivated plants, and have experienced steep population declines worldwide. Bee foraging behavior can be influen...

Morphology and phenology influence plant–pollinator network structure, but whether they generate more stable pairwise interactions with higher pollination success remains unknown. Here we evaluate the importance of morphological trait matching, phenological overlap and specialisation for the spatio‐temporal stability (measured as variability) of pl...

Agricultural intensification and landscape heterogeneity affect the composition of biotic communities, structuring the resources present in the landscape and the species and interactions that support agroecosystems. To evaluate this, the system was studied around blueberry fields, inserted in the Entre Ríos Espinal landscape, which is composed of d...

Liana dynamics in secondary and mature forests are well known in tropical areas dominated by native tree species. Outside the tropics and in secondary forests invaded by exotic species, knowledge is scarce. In this study, we compare liana communities between secondary and mature forests dominated by native species in a subtropical montane area of S...

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield–related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance...

Las comunidades de polinizadores silvestres insertas dentro de los agroecosistémas se encuentran influenciadas localmente por la heterogeneidad espacial (complejidad y contexto del paisaje), en términos de recursos y composición. Se ha observado que, en ciertos casos, la heterogeneidad del paisaje puede compensar, al menos parcialmente, la pérdida...

La complejidad de las comunidades naturales es el resultado de las diferentes especies que coexisten dentro de ellas interactuando de manera desigual. Una de las posibles interacciones está representada por los parásitos. Estos son un componente integral e importante de las comunidades naturales, no sólo porque representan una parte sustancial de l...

Understanding how bees use resources at a landscape scale is essential for developing meaningful management plans that sustain populations and the pollination services they provide. Bumblebees are important pollinators for many wild and cultivated plants, and have experienced steep population declines worldwide. Bee foraging behavior can be influen...

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by few abundant species or rely on high richness remains unclear. Using a global database from 89 crop systems, we partition the relative importance of abundance and s...

Mutualistic interactions are at the core of community dynamics, determining dispersal, colonization, and differential survival and reproduction among individuals and species. Mutualistic interactions therefore affect the fitness of interaction partners, hence modifying their respective evolutionary trajectories reciprocally, potentially leading to...

El desafío de compatibilizar la intensificación agrícola con la conservación de la biodiversidad es evidente en Argentina, reflejándose como una presión de cambio para comunidades tales como las abejas silvestres, siendo actores esenciales para la polinización e incremento de la calidad nutricional de los cultivos, además de aportar un agregado de...

El trabajo es parte de un proyecto en desarrollo cuyo objetivo es determinar si los remanentes de bosque de Chaco Seco inmersos en una matríz agrícola prestan servicios ecosistémicos, es decir, determinar si son funcionales ecológicamente. Para ello estamos cuantificando a través de un diseño de parcelas de Gasparri y Baldi (2013) adaptado a cada f...

A�������. Pre-dispersal filters imposed on the seed stage can alter the likelihood of seed dispersal. We evaluate pre-dispersal seed loss due to predation by insects and abortion in Prosopis flexuosa and P. chilensis. This study was conducted in two protected areas in the Monte Desert. We collected P. flexuosa and P. chilensis fruits from different...

Pre-dispersal filters imposed on the seed stage can alter the likelihood of seed dispersal. We evaluate pre-dispersal seed loss due to predation by insects and abortion in Prosopis flexuosa and P. chilensis. This study was conducted in two protected areas in the Monte Desert. We collected P. flexuosa and P. chilensis fruits from different trees, fr...

The delivery of ecosystem services, such as biotic pollination is a benefit that nature provides us. Pollinators increase the quantity, quality and stability of crops for food production. Previous works show that proximity to natural habitats increases crop production through the delivery of pollination services. However, similar researches in subt...

Fire represents a frequent disturbance in many ecosystems, which can affect plant–pollinator assemblages and hence the services they provide. Furthermore, fire events could affect the architecture of plant–pollinator interaction networks, modifying the structure and function of communities. Some pollinators, such as wood‐nesting bees, may be partic...

In visually-driven seed dispersal mutualisms, natural selection should promote plant strategies that maximize fruit visibility to dispersers. Plants might increase seed dispersal profitability by increasing conspicuousness of fruit display, understood as a plant strategy to maximize fruit detectability by seed dispersers. The role of different pla...

The commensalistic interaction between vascular epiphytes and host trees is a type of biotic interaction that has been recently analysed with a network approach. This approach is useful to describe the network structure with metrics such as nestedness, specialization and interaction evenness, which can be compared with other vascular epiphyte-host...

The commensalistic interaction between vascular epiphytes and host trees is a type of biotic interaction that has been recently analysed with a network approach. This approach is useful to describe the network structure with metrics such as nestedness, specialization and interaction evenness, which can be compared with other vascular epiphyte-host...

El crecimiento de la población humana plantea el desafío de satisfacer sus demandas haciendo un uso eficiente y productivo de las tierras, tratando a la vez de mantener y conservar los ambientes naturales. En el Chaco Seco de Argentina, los remanentes lineales de bosque nativo se implementan como barreras contra factores erosivos y fuego. Pueden ac...

Significance Many of the world’s crops are pollinated by insects, and bees are often assumed to be the most important pollinators. To our knowledge, our study is the first quantitative evaluation of the relative contribution of non-bee pollinators to global pollinator-dependent crops. Across 39 studies we show that insects other than bees are effic...

Los bosques nativos proveen importantes servicios ambientales, siendo la madera muerta (MM) de vital importancia para las comunidades locales como combustible y para la construcción de los puestos ganaderos. La MM tiene otras funciones ecológicas como la provisión de sitios de nidifica-ción para polinizadores. Este estudio evaluó el efecto de la di...

The fate of dispersed seeds from mammal faeces depends both on the animal that finds the seeds and environmental conditions. We explored the simultaneous influence of microhabitat and food availability on seed predation and removal from faeces by different animals in a protected Prosopis flexuosa open woodland site of the central Monte desert (Arge...

Understanding the relationships between trait diversity, species diversity and ecosystem functioning is essential for sustainable management. For functions comprising two trophic levels, trait matching between interacting partners should also drive functioning. However, the predictive ability of trait diversity and matching is unclear for most func...

En la sierra de San Javier (Tucumán, Argentina) se presentan bosques secundarios nativos e invadidos, estos últimos dominados por Ligustrum lucidum, que afecta la biodiversidad nativa. Analizamos la influencia del bosque dominado por L. lucidum sobre las comunidades de lianas en comparación con bosques secundarios nativos sin dominancia de especies...

Native and invaded secondary forests are present in sierra de San Javier, the latter dominated by Ligustrum lucidum, which exerts an influence on native biodiversity. We analyzed the influence of the forest dominated by L. lucidum over liana communities compared to native secondary forests without dominance of exotic species. Forests were compared...

The fate of dispersed seeds from mammal faeces depends both on the animal that finds the seeds and environmental conditions. We explored the simultaneous influence of microhabitat and food availability on seed predation and removal from faeces by different animals in a protected Prosopis flexuosa open woodland site of the Central Monte Desert (Arge...

Co-flowering plant species commonly share flower visitors, and thus have the potential to influence each other's pollination. In this study we analysed 750 quantitative plant-pollinator networks from 28 studies representing diverse biomes worldwide. We show that the potential for one plant species to influence another indirectly via shared pollinat...

In the Report “Wild Pollinators Enhance Fruit Set of Crops Regardless of Honey Bee Abundance,” it is possible that some pollinator species were misidentified in lowland coffee, Uganda, one of the 41 studies included in the synthesis. This potential misidentification does not invalidate the analyses, conclusions, or the wider implications of the stu...

Bees provide essential pollination services that are potentially affected both by local farm management and the surrounding landscape. To better understand these different factors, we modelled the relative effects of landscape composition (nesting and floral resources within foraging distances), landscape configuration (patch shape, interpatch conn...

Diversity and abundance of wild-insect pollinators have declined in many agricultural landscapes. Whether such declines reduce crop yields, or are mitigated by managed pollinators such as honey bees, is unclear. Here, we show universally positive associations of fruit set with wild-insect visits to flowers in 41 crop systems worldwide, and thus cle...

How many dimensions (trait-axes) are required to predict whether two species interact? This unanswered question originated with the idea of ecological niches, and yet bears relevance today for understanding what determines network structure. Here, we analyse a set of 200 ecological networks, including food webs, antagonistic and mutualistic network...

Background/Question/Methods Understanding patterns of temporal variation in plant-pollinator networks and their underlying causes has important implications for mechanisms of evolution and resilience of communities and ecosystem services to environmental change. Plant-pollinator interactions are among the most studied ecological interactions. In...

Background/Question/Methods: To understand biodiversity patterns in a community, and the mechanisms by which biodiversity is generated and maintained, it is essential to study the patterns of interactions among the species within the community. Interaction patterns can be complex, but recent methods in network ecology allow us to identify certain...

Recent studies of plant-animal mutualistic networks have assumed that interaction frequency between mutualists predicts species impacts (population-level effects), and that field estimates of interaction strength (per-interaction effects) are unnecessary. Although existing evidence supports this assumption for the effect of animals on plants, no st...

Sustainable agricultural landscapes by definition provide high magnitude and stability of ecosystem services, biodiversity and crop productivity. However, few studies have considered landscape effects on the stability of ecosystem services. We tested whether isolation from florally diverse natural and semi-natural areas reduces the spatial and temp...

Most rare species appear to be specialists in plant-pollinator networks. This observation could result either from real ecological processes or from sampling artifacts. Several methods have been proposed to overcome these artifacts, but they have the limitation of being based on visitation data, causing interactions involving rare visitor species t...

Mutualisms provide benefits to interacting species, but they also involve costs. If costs come to exceed benefits as population density or the frequency of encounters between species increases, the interaction will no longer be mutualistic. Thus curves that represent benefits and costs as functions of interaction frequency are important tools for p...

A sizable proportion of agricultural production depends directly or indirectly on animal pollination but estimation of the size of this dependence is missing for most countries, even for some of the most important food producers. Here, we evaluate the current status and temporal trends (1961-2007) in pollinator dependency of Argentinean agriculture...

Plant–insect interactions and their implications for agricultural systems in premontane forests of the High Bermejo: the case of Citrus paradisi (Grapefruit). The Yungas premontane forests have been highly transformed for agriculture and they are represented by forest fragments embedded in an agricultural matrix. This transformation alters...

Increasing crop genetic diversity has the potential to enhance pollination services, by contributing to the long-term stability of agroecosystems. Different species of the genus Citrus, including grapefruit, are cultivated worldwide. In Ar-gentina, 30% of the total national yield is concentrated in the northwestern part of the country where new cul...

The structure of mutualistic networks is likely to result from the simultaneous influence of neutrality and the constraints imposed by complementarity in species phenotypes, phenologies, spatial distributions, phylogenetic relationships, and sampling artifacts. We develop a conceptual and methodological framework to evaluate the relative contributi...

Pollen limitation occurs when plants produce less fruits and/or seeds than they would with adequate pollen receipt. If the addition of cross-pollen to stigmas increases fruit/seed production, it is interpreted as an evidence of pollen limitation. Much of the limitation may be associated with the quality rather than quantity of pollen; however, most...

A decline in pollination function has been linked to agriculture expansion and intensification. In northwest Argentina, pollinator visits to grapefruit, a self-compatible but pollinator-dependent crop, decline by approximately 50% at 1km from forest edges. We evaluated whether this decrease in visitation also reduces the pollination service in this...

The consequence of a proposed pollinator decline for agriculture is a subject of much ongoing debate. However pollination requirements of many cultivated plants remain unknown. Citrus is complex in terms of pollination needs because of great variation in breeding systems among and within species, and even among and within cultivars. The objective o...

Habitat fragmentation is a major cause of functional disruption in plant-animal interactions. The net effect on plant regeneration is, however, controversial because a given landscape change can simultaneously hamper mutualism and attenuate antagonism. Furthermore, fragmentation effects may emerge at different spatial scales, depending on the size...

1 RESEARCH S tudies on crop pollination by native and nonnative insects are becoming increasingly critical because of a perceived global decline in pollinator stocks, a subject of much current debate with great economical and conservation consequences (Ghazoul, 2005a, 2005b; Steff an-Dewenter et al., 2005). Insect pollination is determinant or bene...