Figure 1 - uploaded by Claudia Maria Jacobi
Content may be subject to copyright.
Terminal branch of Stachytarpheta glabra. (a) inflorescence, (b) details of anther location inside the corolla. Notice the spatial separation between anthers and stigma.
Source publication
The production and predictability of nectar resources in a population of Stachytarpheta glabra (Verbenaceae) and their use by insects and hummingbirds on ironstone outcrops in south-east Brazil were investigated. The phenology, density, nectar production, reproductive biology and floral visitors were studied, as well as territory size and daily nec...
Context in source publication
Context 1
... defence of nectar sources is common among hummingbirds. Both theoretical models and empirical results have pointed out the convenience of defending smaller but high-value territories (Cotton 1998, Dearborn 1998, Temeles et al . 2005), and reducing agonistic encounters when food is abundant, predictable, and of high quality (Powers & Conley 1994). When options are reduced, however, territory holders continue to defend a resource that is not energetically suitable (Heinemann 1992). One of the most characteristic plant species on ironstone fields is Stachytarpheta glabra Cham., to which a diversity of nectar-feeding insects has been related (Antonini et al. 2005). Hummingbirds, most notably Colibri serrirostris (Vieillot), have also been reported to use this species as a nectar resource (Vincent et al. 2002). In view of the environmental constraints for plant establishment, which reduces the variety and seasonal availability of resources for floral visitors, and more specifically nectar-feeders, S. glabra appears to be a key resource for this guild. Thus, our aims were (1) to evaluate the distribution of floral resources of S. glabra in time and space in a population growing over ironstone; (2) to determine the plant’s dependence on pollinators and their behaviour; (3) to assess nectar defence by the territorial hummingbird C. serrirostris . The study was conducted in an area of ironstone outcrops belonging to Serra do Rola Mo ̧a State Park (20 ◦ 03 60 S, 44 ◦ 02 00 W, c . 1300 m asl), one of the very few conservation units in Brazil that harbour haematitic ecosystems. It is located within the Iron Quadrangle, a geological formation known for its high-quality iron-ore deposits (Simmons 1968). The climate in the region is mesothermic, with a mean annual rainfall of 1500 mm concentrated during November–March, and a dry season with high risk of fire (Nimer & Brand ao 1989). These climatic conditions sustain savannas and fragments of Atlantic forest below 1000 m. Above this altitude, the very shallow soils (where they exist) preclude retention of water and organic matter, there is high daily thermal variation, and strong winds blow. Individuals of S. glabra are shrubs occurring in large, dense patches, and the species is one of the most characteristic in ironstone outcrops (Jacobi et al. 2007, Viana & Lombardi 2007). Inflorescences are conspicuous, terminal, and composed of tubular blue flowers (Atkins 2005). Each inflorescence bears approximately 36 flowers, which open up to five at a time and last for 1 d. Each flower is 12.8 ± 1.44 mm long (n = 25), has a bicarpellate ovary with one ovule per locule, a long thin style ending in a small stigma protruding 2–3 mm beyond the corolla mouth (3.78 ± 0.23 mm, n = 25), two staminodes and two epipetalous stamens inside the corolla (Figure 1). The white-vented violetear C. serrirostris is the most common hummingbird in the area (Vincent et al. 2002). Individuals have a mass of 6.0 ± 0.7 g (n = 5) and a bill length of 21.8 ± 1.3 mm (n = 8). Males and females are indistinguishable. The species is widespread in the cerrado biome (Sick 1997). It is territorial and known for its constant calls while perching, which help territory owners defend their ground against conspecifics and other hummingbird species. To establish the predictability of nectar resources, we evaluated the quantity and duration of floral resources in a natural population. We censused, monthly over 2 y (2001–2002), 120 to 140 randomly chosen plants in the population, over an area of approximately 1 km 2 . Individuals smaller than 15 cm high were excluded. On each occasion we measured the height of each individual and the quantity of open flowers, and we classified each plant according to the predominance of four phenological categories: vegetative, flower buds, green fruits, and dry fruits. During the first year, the crown maximum diameter was also measured. The density of floral resources was evaluated on four occasions, to compare dense and less-dense areas, at the peak and end of the flowering season. We counted the total number of plants and of newly open flowers in 40 1-m 2 randomly located plots on each occasion. The pat- tern of plant distribution was determined in each case by testing the variance/mean ratio against a χ 2 distribution, with 39 degrees of freedom (Southwood & Henderson 2004). If the ratio is significantly > 1, plants are aggregated. Flowers (n = 40, from 10 plants) were bagged to estimate daily nectar volume and sugar concentration (using a pocket refractometer). Inflorescences with buds were bagged the night before, and the nectar from each flower was extracted with a micro-syringe twice in the morning (06h30 and 08h30) and twice in the afternoon (13h30 and 16h30). In addition, 21 flowers were bagged from 06h30 to 15h30 to estimate daily production without nectar removal. Sporadic concentration measurements in non-bagged flowers were performed as early as 05h30 and as late as ...
Similar publications
While nectar bats have been found to carry nearly seven times as much pollen as hummingbirds, many other details of pollen transport by these nocturnal pollinators remain poorly understood. For bees, the majority of the pollen they pick up from a flower is deposited on the following one or two flower visits because they groom heavily, while for hum...
Reproductive biology of Amasonia campestriswas studied in the Venezuelan Central Llanos. The flowers open between 3:30 and 7:00 h, and last for two days. The flowers are protandrous and the number of opened flowers per inflorescence varies between 1 and 5 ( X = 2.2, SD = 2.3). The nectar is produced and accumulated in a basal cavity of the corolla....
Psittacanthus is the only genus in the family Loranthaceae that is considered a significant pest of woodlands and farmlands in Mexico and Central America, but relatively little attention has been given to the reproductive biology and pollination of natural populations. We present quantitative information on the floral morphology, breeding system, f...
This paper provides the first description of the exploitation of floral resources of Ceiba pubiflora by birds in the
Neotropical region. We sampled five different specimens of C. pubiflora, focusing on plant-bird and bird intra/interspecific aggressive interactions. We recorded thirteen species of birds exploiting its floral resources. Only humming...
The Proteaceae are renowned for their floral diversity but surprisingly the role of pollinators in driving evolutionary divergence in this family has been underexplored. Here we focus on recently diverged taxa to gain insight into the processes that generate diversity by testing whether two varieties of Leucospermum tottum might have originated by...
Citations
... The specimen cited as S. glabra by Messias et al. (2017) (voucher M.C.T.B Messias 1016, from inside the Park, was reidentified as S. commutata. We opted to include this species in the taxonomic treatment, because it occurs in the Serra do Itacolomi, over canga, which is a vegetation type severely threatened (Jacobi & Carmo 2008;Jacobi et al. 2011), and it is a species recognized for its important ecological role (Jacobi & Antonini 2008). Other species present in this area of canga are Lippia hermannioides Cham. ...
Abstract Verbenaceae includes 32 genera and approximately 800 species distributed mainly in the Neotropical region, especially diversified in Brazil, where the campo rupestre stands out as an important vegetation type for the family. The Itacolomi State Park (ISP) is located in the southeast of the Quadrilátero Ferrífero, Minas Gerais state (MG), Brazil. Vegetation at the Park is composed of campo rupestre and forest remnants among degraded areas. The present research provides a floristic treatment of Verbenaceae in this protected area. Data were obtained from fieldwork and herbarium study. A total of 13 species were recorded: Glandularia phlogiflora, Lantana camara, Lantan fucata, Lantana tiliaefolia, Lantana trifolia, Lippia brasiliensis, Lippia hermannioides, Lippia origanoides, Petrea volubilis, Stachytarpheta cayennensis, Stachytarpheta commutata, Verbena litoralis and Verbena rigida. Among them, six are new records for the ISP. Stachytarpheta glabra, endemic to MG, was found in an area of canga very close to the boundaries of the Park. Additionally, S. viscidula, whose type locality is close to the Park, is proposed as a new synonym for S. commutata, whose type specimen comes from the Park. We provide an identification key, descriptions, photographs and comments on taxonomy, ecology and distribution for each species.
... (Fonseca et al. 2006) and S. glabra Cham. (Antonini et al. 2005;Jacobi & Antonini 2008). The only phenological studies in the genus were also conducted in these two latter species (Jacobi & Antonini 2008;Fonseca et al. 2006). ...
... (Antonini et al. 2005;Jacobi & Antonini 2008). The only phenological studies in the genus were also conducted in these two latter species (Jacobi & Antonini 2008;Fonseca et al. 2006). The focus of this research is the microendemic species Stachytarpheta cassiae (S. ...
... However, such extended flowering period is reported for other Stachytarpheta species such as S. cayennensis (Rich.) J. Vahl in the Cerrado (Arruda et al. 2009) and S. glabra in rupestrian grasslands in southeastern Minas Gerais (Jacobi & Antonini 2008). On the other hand, Machado & Oliveira (2015) observed that the flowering of S. gesnerioides Cham occurred only from January to March in cerrado domains of central Brazil. ...
The flora of the Brazilian rupestrian grasslands represents a hotspot of species richness and endemisms. Stachytarpheta cassiae (Verbenaceae), is a micro endemic species, from which nothing is known. Here, we quantified the activity and intensity of vegetative and reproductive phenophases throughout 12 months and tested for their seasonality and their relationship with local climatic variables. Both vegetative and reproductive phenophases were continuous. No seasonality was observed in the vegetative phenophases and none of them was influenced by climatic variables. Only flower buds and mature fruits’ intensities showed seasonality in February (rainy season) and July (dry season), respectively. Accordingly, increased temperature and humidity combined explained increased production of flower buds whereas decreased rainfall explained increased mature fruits. Higher intensity in flower buds may respond to similar climatic conditions as other species in the community. However, S. cassiae is much different as it continues producing flowers continuously. Higher intensity of mature fruits in the dry season is expected as their seeds are abiotically dispersed. Due to constant flower and leaf production, S. cassia may be a key species for the conservation of many vertebrate and invertebrate species and for maintaining the biogeochemical functioning of the impoverished soils of the rupestrian grasslands.
... Even the ability to hover, which was considered to be unique to hummingbirds for a long time (Stiles 1981;Fleming and Muchhala 2008), was documented in sunbirds (Geerts and Pauw 2009a;Wester 2014). Moreover, plants adapted to hovering sunbirds also occur in the African tropics (Janeček et al. 2011; Bartoš and Janeček 2014;Sejfová et al. 2021) and sunbirds also drive insects away from food plants in their territories (Ollerton and Nuttman 2013;Tropek et al., 2013), as hummingbirds do (Jacobi and Antonini 2008). In both bird groups, we found a high variability in morphological and behavioural nectarivory-related traits, such as bill length, bill curvature or ability to hover, which enable resource partitioning (Paton and Collins 1989;Janečková et al. 2021; see also Adler et al. 2013). ...
Differences in interaction specializations between nectarivorous birds and plants across continents serve as common examples of evolutionary trajectory specificity. While New World hummingbird-plant networks have been extensively studied and are considered highly specialized, knowledge on the network specialization of their Old World counterparts, sunbirds (Nectariniidae), remains limited. A few studies from tropical Africa indicate that sunbird-plant networks are rather generalized. Unfortunately, these studies are limited to dry seasons and high elevations at the tree line, environments where niche-based hypotheses also often predict lower resource partitioning. In our study, we explored the specialization of sunbird-plant networks and their spatiotemporal variability on Mt. Cameroon (Cameroon). Using a combination of automatic video recordings and personal observations, we constructed eight comprehensive sunbird-plant networks in four forest types at different elevations in both the dry and wet seasons. As reported in previous studies, the montane forest plants, birds and whole networks were highly generalized. Nevertheless, we observed a much higher specialization in forests at lower elevations. Except at the lowest altitude, the wet season was also characterized by higher specialization. While less specialized flowering trees dominated in the dry season networks, more specialized herbs and shrubs were visited by birds during the wet season. As our findings do not support the generally accepted assumption that Old World bird-plant networks are rather generalized, we need further studies to understand the differences in bird-plant specializations on individual continents.
... The greater abundance in the rupestrian fields of a hummingbird known to be territorialist (Jacobi & Antonini 2008, Justino et al. 2012 seems to be associated with the greater exclusivity of the interactions in these environments. In this context, C. serrirostris was the exclusive visitor of five plant species in the rupestrian field, including the species Barbacenia lymansmithii, endemic to the SCNP (Mello- Silva & Menezes 1999). ...
Hummingbirds are specialized in consumption of nectar and play an important role in Neotropical plant communities acting as pollinator organisms. Despite the importance of this mutualistic interaction, studies about hummingbird-plant relationships remain scarce regarding the Cerrado domain (Brazilian savanna). In this study, we aimed to describe the interaction network between hummingbirds and plants in rupestrian fields and riparian forests located in altitudinal areas of the Serra da Canastra National Park. We established two transects in each phytophysiognomy, that were sampled monthly for four days, from November 2018 to October 2019. Flowering plants in each transect were observed each survey, and all the visiting hummingbirds were recorded. Networks were constructed using the R bipartite package, considering each phytophysiognomy type, and grouping data of both environments. From these three network arrangements, we extracted complementary metrics at the community level (modularity, nestedness, and network specialization index), and at the species level (species specialization index and species strength in the network). We recorded 647 interactions between 10 hummingbird species and 23 flowering plant species. The hummingbird Colibri serrirostris was responsible for most of observed bird-plant interactions and the plant Qualea cordata was the most visited. The general network was significantly modular, comprising four modules, and showed considerable high specialization and low nestedness. The interaction network in the rupestrian field showed a higher specialization, nestedness, and modularity index when compared to riparian forests, while the metrics of this ecosystem did not differ from those of the general network. However, the metrics at hummingbird species level did not differ significantly between phytophysiognomies. This study corroborated some findings about hummingbird-plant networks in other areas of the Cerrado domain, but also pointed idiosyncrasies in networks of the investigated phytophysiognomies, especially the rupestrian fields.
... Even the ability to hover, which was for a long time considered as a hummingbird privilege (Stiles 1981;Fleming and Muchhala 2008), was documented in sunbirds (Geerts and Pauw 2009a;Wester 2014). Moreover, it has been shown that plants adapted to hovering sunbirds occur also in African tropics (Janeček et al. 2011; Bartoš and Janeček 2014;Seifová et al. 2021) and that sunbirds are also driving away insects from the food plants in their territories (Ollerton and Nuttman 2013;Tropek et al., 2013) as hummingbirds do (Jacobi and Antonini 2008). In both bird groups, we can nd high variability in morphological and behavioral nectarivory related traits such as in bill length, bill curvature or ability to hover, which enable resource partitioning (Paton and Collins 1989;Janečková et al. 2021; see also Adler et al. 2013). ...
Differences in bird-flower interaction specialization across continents serve as a common example of evolutionary trajectory specificity. While New World hummingbird-flower networks have been subject to numerous studies and are considered highly specialized, our knowledge of network specialization for their Old World counterparts, sunbirds (Nectariniidae), is completely insufficient. A few studies from tropical Africa indicate that sunbird-flower networks are rather generalized. Unfortunately, these studies are limited to dry seasons and high elevations around the tree-line, the environments where also niche-based hypotheses often predict lower resource partitioning. In our study, we explore the specialization of sunbird-flower networks and their spatio-temporal variability on Mt. Cameroon (Cameroon). Using a combination of automatic video recording and personal observations, we constructed eight comprehensive sunbird-flower networks in four forest types occurring in different elevations and in both the dry and wet season. As reported by previous studies the montane forest plants, birds and whole networks were highly generalized. Nevertheless, we observed much higher specialization in forests in lower elevations. The wet season was also characterised by higher, but not significant, specialization. While less specialized flowering trees dominated in dry season networks, more specialized herbs and shrubs were visited during the wet season. Whereas our findings do not support the generally accepted assumption that Old World bird-flower networks are rather generalized, we need further studies to understand the differences in bird-flower specialization on individual continents.
... Environments under soils with iron saturation, so-called 'bounded iron formation', such as Brazilian 'Canga' (Skirycz et al., 2014) and 'African ferrictes' (Porembski, Fischer, & Biedinger, 1997) are commonly associated with high biological diversity and endemism (Jacobi, Carmo, Vincent, & Stehmann, 2007;Gibson, Yates, & Dillon, 2010;Fernandes, Maia, Monteiro, & Condé, 2016). The presence of this factor is reported as influential to the mesofauna (Moras, Gomes, & Tavares, 2015), underground biology (Ferreira, 2005), avifauna (Pacheco et al., 2007), ecological interactions (Jacobi & Antonini, 2008;Dáttilo et al., 2014), and to vegetation characteristics (Jacobi et al., 2007;Vincent & Meguro, 2008;Gibson et al., 2010;Gibson, Meissner, Markey, & Thompson, 2012). Regarding this last group, the presence of environmental filters associated with iron saturation and microhabitat diversity are factors considered as regulators of plant communities and beta diversity potentiators in ferruginous systems (Porembski et al., 1997;Vilela, Melo, Costa, Logoeiro, & Varajão, 2004;Jacobi et al., 2007;Vincent & Meguro, 2008). ...
Our objective was to evaluate the floristic and structural relationships between Canga tree communities and other vegetation types inserted in the physiognomic units set, in order to test the hypothesis that these communities have unique characteristics due to their specific environmental conditions. For this, we compared the structural and floristic attributes of Canga vegetation with adjacent semideciduous seasonal forest, Savanna and ecotone areas, evaluating the similarity in its behavior. Our results demonstrate the existence of distinct relationships among vegetation types in relation to different perspectives, related to macro-scale environmental attributes and to the phytogeographic context. In general, Canga tree vegetation has its structure associated with open vegetation types, such as the Cerrado (Savanna) and its composition associated with forest vegetation types, constituted by a community with specific ecological characteristics. Our results suggest the presence of ferruginous soils as a factor that contributes to environmental and ecological heterogeneity in vegetation matrices.
... According to Jacobi and Carmo (2011), in rupestrian grasslands plant commu-nities, insect-pollinated species represent 70% of the species, while bird-pollinated plants comprise 13%, and 16% are wind-pollinated. Flowers adapted to hummingbird pollination are common in rupestrian grasslands, and these bird species show strong territoriality to defend flower resources in nectar rich plant species (Guerra et al., 2014;Jacobi and Antonini, 2008;Machado 2009;Sazima and Sazima 1990;Vasconcelos and Lombardi 2001). Nevertheless, hummingbirds visit more often non-ornithophilous than ornithophilous plant species (Rodrigues and Rodrigues, 2014;Vasconcelos and Lombardi 2001), thus could play different roles in reproduction of some species, as larcenists (thieves and robbers) or pollinators. ...
... In the rupestrian grasslands, insect-pollination (mostly beepollinated) represent about 70% of plant species, whereas bird-pollinated plants are represented by 10-15% of animalpollinated plant diversity (Carstensen et al., 2014;Jacobi and Carmo, 2011). Some endemic species are exclusively bee-pollinated (Franco and Gimenes, 2011;Jacobi et al., 2000;Matias et al., 1996), and others involve bees and hummingbirds as pollinators (Jacobi and Antonini, 2008;Sazima and Sazima, 1990). To avoid temporal bias on floral visitors community, here we conducted observations in both rainy and dry season, since a high variation in pollination assemblage has been reported between seasons along the year, with ornithophily prevailing during the dry season (Conceiç ão et al., 2007). ...
... Based on this, it is not surprising that aggressive defending of nectar resources is mostly documented among closely related species of a similar size (Colwell 1973;Johnson and Hubbell 1974;Kodric-Brown and Brown 1978). In contrast, only a few studies have reported this behaviour among unrelated nectarivores (Jacobi and Antonini 2008;Ollerton and Nuttman 2013;Tropek et al. 2013). This kind of interference competition mostly happens between small birds and large insects (Boyden 1978;Lyon and Chadek 1971;Primack and Howe 1975;Tropek et al. 2013). ...
... As shown in many studies, differences in body size in terms of metabolic costs affect the higher preference of larger species to utilise and defend the richest food sources, maximising the foraging efficiency (Ballance et al. 1997;Gill and Wolf 1975;Palmer et al. 2003;Riegert et al. 2011;Tropek et al. 2013). This pattern might explain why chasing of insects by relatively large sunbirds (Ollerton and Nuttman 2013;Tropek et al. 2013) is reported much less often then chasing of insects by small hummingbirds (Jacobi and Antonini 2008;Primack and Howe 1975;Stoaks 2000). ...
There are two alternative hypotheses related to body size and competition for restricted food sources. The first one supposes that larger animals are superior competitors because of their increased feeding abilities, whereas the second one assumes superiority of smaller animals because of their lower food requirements. We examined the relationship between two unrelated species of different size, drinking technique, energy requirements and roles in plant pollination system, to reveal the features of their competitive interaction and mechanisms enabling their co-existence while utilising the same nectar source. We observed diurnal feeding behaviour of the main pollinator, the carpenter bee Xylocopa caffra and a nectar thief, the northern double-collared sunbird Cinnyris reichenowi on 19 clumps of Hypoestes aristata (Acanthaceae) in Bamenda Highlands, Cameroon. For comparative purpose, we established a simplistic model of daily energy expenditure and daily energy intake by both visitor species assuming that they spend all available daytime feeding on H. aristata. We revealed the energetic gain–expenditure balance of the studied visitor species in relation to diurnal changes in nectar quality and quantity. In general, smaller energy requirements and related ability to utilise smaller resources made the main pollinator X. caffra competitively superior to the larger nectar thief C. reichenowi. Nevertheless, sunbirds are endowed with several mechanisms to reduce asymmetry in exploitative competition, such as the use of nectar resources in times of the day when rivals are inactive, aggressive attacks on carpenter bees while defending the nectar plants, and higher speed of nectar consumption.
... De modo geral, os estudos sobre interações ecológicas no QF são relativamente recentes e têm focalizado informações sobre a relação entre plantas e seus visitantes florais (e.g. Borba & Semir 2001, Jacobi & Antonini 2008, Loyola et al. 2007, insetos herbívoros (de adultos e formas juvenis de vida livre, até minadores e galhadores) e também formigas que defendem as plantas contra estes herbívoros (e.g. Vincent et al. 2002, Lanza et al. 2005, Dáttilo et al. 2014. ...
O que sabemos sobre as interações ecológicas em ambientes de canga? Talvez devido à grande diversidade vegetal, e ao componente arbóreo pouco representativo, a maioria dos estudos sobre interações ecológicas em ambientes de canga centra-se nas relações entre plantas arbustivas e seus insetos visitantes. Entretanto, diferentemente do conhecimento atual sobre a diversidade florística, as interações ecológicas são ainda mal conhecidas em campos rupestres ferruginosos, como é o caso do Quadrilátero Ferrífero (QF). Esta lacuna constitui um grande problema devido à importância desse ecossistema como mantenedor de grande número de espécies endêmicas e frente à velocidade com que as cangas estão sendo destruídas pela crescente demanda por minério de ferro (Jacobi & Carmo 2008, 2011). De modo geral, os estudos sobre interações ecológicas no QF são relativamente recentes e têm focalizado informações sobre a relação entre plantas e seus visitantes florais (e.g. Borba & Semir 2001, Antonini et al. 2005, Jacobi & Antonini 2008, Loyola et al. 2007), insetos herbívoros (de adultos e formas juvenis de vida livre, até minadores e galhadores) e também formigas que defendem as plantas contra estes herbívoros (e.g. Vincent et al. 2002, Lanza et al. 2005, Dáttilo et al. 2014). Diferentemente dos levantamentos florísticos, com registros amplamente distribuídos nas principais serras do QF, trabalhos focalizando interações foram realizados principalmente no Parque Estadual da Serra do Rola Moça (PESRM) em Belo Horizonte, Parque Estadual do Itacolomi (PEIT) em Mariana, Serra da Brígida em Ouro Preto, no Campus da Universidade Federal de Ouro Preto, e em Barão de Cocais. Estes estudos foram desenvolvidos principalmente nos campos ferruginosos sobre canga, seja do tipo nodular (mais intemperizada) ou couraçada (predominância de afloramentos rochosos). A compilação de resultados dos quase 40 estudos que contemplaram diferentes aspectos das interações ecológicas em cangas do QF foi sintetizada na forma de rede bipartida (Fig. 1). As linhas indicam o vínculo entre local de estudo e tipo de interação, e sua espessura, a quantidade relativa de estudos para esse par. O PESRM aparece como o principal local de estudos sobre interações no QF, por isso ele se encontra no topo do gráfico. Este parque é uma das raras Unidades de Conservação de Proteção Integral que atualmente tem como prioridade proteger os ecossistemas de campos ferruginosos. O mutualismo (principalmente polinização) e o parasitismo são as principais interações abordadas, mas apenas o mutualismo foi investigado em todos os locais.
... In addition, the use of these species (chiropterophilous-ornithophilous) by the hummingbirds appears to be common in the campos rupestres of the Espinhaço Range (8% of plants visited by the hummingbirds in this study, 12% in the campos rupestres of the northern portion of the Espinhaço Range; Machado et al., 2007) compared with other open-habitat mountaintops, such as the campos de altitude (no species; Freitas and Sazima, 2006), the Atlantic Forest (no species; Andrade, 2006), Pantanal (no species; Araujo and Sazima, 2003) and cerrado sites (no species; Araújo et al., 2011; Rodrigues and Araujo, 2011). Many hummingbird species are commonly recorded defending feeding territories in the campos rupestres (Vasconcelos and Lombardi, 2001; Jacobi and Antonini, 2008). At our study site, only the C. serrirostris and the males of A. scutatus were observed to defend territories and participate in the highest number of agonistic interactions. ...
The hummingbird-visited plant community located on the open-habitat mountaintop of the Espinhaço Range was studied for two years (from August 2007 to July 2009) in Serra do Cipó National Park, Southeastern Brazil (19° 15' S and 43° 31' W). The floral characteristics and flowering period of the hummingbird-visited plants was monthly recorded along trails located in three vegetation types: (1) typical campos rupestres (TCR), (2) open fields (OPF), and (3) capões de mata (CAM). Hummingbird visitation was observed in 51 plant species, 22 ornithophilous and 29 non-ornithophilous species. The TCR showed the greatest number of species visited (N = 38), followed by the OPF (N = 18) and CAM (N = 17). Six species of hummingbirds were recorded visiting flowers: Augastes scutatus, Campylopterus largipennis, Colibri serrirostris, Chlorostilbon lucidus, Eupetomena macroura and Phaethornis pretrei. This study demonstrates that the species richness and the number of ornithophilous species visited by the hummingbirds at the study site are more similar to hummingbird-plant communities of the Atlantic Forest than to those of the Cerrado communities and other Brazilian highland open-habitat communities. The plant families most visited by hummingbirds were Bromeliaceae and Asteraceae. Although the Asteraceae family is rarely used as a food resource for hummingbirds in other high and lowland communities, in the study site this family is used mainly by the endemic hummingbird Augastes scutatus. We found a large overlap of flowering throughout the year among the species visited by the hummingbirds. Thus, the nectar availability supports these resident hummingbirds. The present study also showed that the studied hummingbird-plant community is composed of many species endemic to the campos rupestres of the Espinhaço Range, some of which are considered to be in danger of extinction, thus constituting a unique and threatened community. Thus, understanding hummingbird-plant pollination dynamics becomes fundamental to the conservation of the campos rupestres.
