DIET OF PARROTS IN AN URBAN AREA OF SÃO PAULO, SOUTHEAST BRAZIL

The climate is changing and temperatures are predicted to further increase in the future. Species respond to these changes by either adapting to the local warmer conditions and/or range shifting to higher latitudes. Some of these successful range shifting plants can become invasive in their new range. Therefore, there is a conceptual analogy of successful range shifts and biological invasions originating from other continents. Intra-continental plant species shift their ranges within the same contiguous land mass from which they originate. Inter-continental species originate from other continents from where they have been introduced before expanding in their new range. The aim of this thesis is to gain a better understanding of the plant-insect interactions that may contribute to the success of exotic plants that have expanded their ranges due to climate warming. More specifically I aimed to clarify whether climate warming-induced range expanding exotic plants are less suitable than native congener plants and whether these plants suffer less from aboveground enemies than native congener plants. In addition, I investigated if inter –and intra-continental exotic plant species differed in their suitability and if they responded differently to potential aboveground enemies. In the first greenhouse experiment, I tested the hypothesis that inter- and intra-continental exotic plants and phylogenetically related native plants from the same habitat do not respond differently to two aboveground polyphagous herbivores. Further I tested if intra- and inter-continental exotic plants experience less negative soil feedback than related native plants. I grew fifteen plant species with and without naive polyphagous locusts (Schistocerca gregaria) and cosmopolitan aphids (Myzus persicae) and exposed all plants to soils from their invaded range in order to test the feedback from the soil community to plant biomass production. My results show that that both inter –and intra-continental exotic plants on average were better defended against aboveground and belowground enemies than related native plant species. This suggests that successful range expanding plants may include species with invasive properties. Exotic plants have been shown to have neutral to positive soil feedbacks, while native plants experience negative effects from their soil biota. Belowground interactions can influence aboveground interactions and may change the relationships between exotic plants and their enemies. I examined how the performance of the two aboveground polyphagous herbivores S. gregaria and M. persicae species was influenced by feedback interactions between the plants and their soil biota and compared these responses in intra- and inter-continental exotic and related native plants. Locust mass was negatively affected by the plant specific soil community and larger on native than on exotic plants. Locust survival was also higher on native plants, but not affected by soil type. There were no differences between inter –and intra-continental plants. Aphid population size was not affected by soil type, but was highest on the intra-continental range expander. The body size of M. persicae was larger on control than on soils with specific plant communities and not affected by plant origin. One way of measuring the release of exotic plants from natural enemies is by comparing their herbivore loads with related plants that are native in the invaded range. These loads can be influenced by top down control of insect predators and parasitoids. In the field, I examined herbivore loads and predator pressure on two exotic (inter-continental and intra-continental) and two related native plant species. I found smaller herbivore loads on the exotic plant species than on the related native plants. Moreover, the herbivores on the exotic plants had a higher predator pressure than herbivores on the phylogenetically related native plants. These results imply that both types of exotic plants have a double advantage: enhanced bottom-up and top-down control of herbivores. Finally, I set up a field experiment to test the effect of herbivory on communities of exotic and native plants. I created ten communities with six exotic plant species and their phylogenetically related native species that co-occur in the same riverine habitat. Half of the communities were exposed to herbivory and the other half was grown in a herbivory-free environment. This study was done in order to test if exotic plants may dominate invaded plant communities exposed to aboveground herbivory and if this advantage of the exotic plants under herbivory would disappear when all plants were free of herbivores. Herbivory reduced aboveground plant biomass by almost half. However, exotic plants did not become the exclusive dominants in these communities, as some native species were well protected against aboveground herbivory as well. Plant species varied considerably in their responses to herbivory resulting in changes in community ranking. Interestingly, the proportional biomass contributions to the community were similar for exotic and native plant species and also not different between inter –and intra-continental plants. I conclude that release from aboveground enemies is not the only factor explaining the invasive success of intra- and inter-continental exotic plant species. In conclusion, climate warming-induced range expanding plant species originating from the same continent may possess invasive properties comparable to introduced inter-continental exotic plants. In the greenhouse and in the field, both inter- and intra-continental exotic plant species were more resistant against aboveground herbivores than native plants. In the greenhouse, the exotic plants suffered less from herbivory than related natives, although this did not result in their absolute dominance in the field when exposed to herbivory. Therefore, aboveground enemy exposure is not the only factor predicting the invasive success of intra- and inter-continental exotic plant species.

While the soil environment is generally acknowledged as playing a role in plant competition, the relative importance of soil resources and soil microbes in determining outcomes of competition between native and exotic plants has rarely been tested. Resilience of plant communities to invasion by exotic species may depend on the extent to which native and exotic plant performance are mediated by abiotic and biotic components of the soil. We used a greenhouse experiment to compare performance of two native prairie plant species and one exotic species, when grown in intraspecific competition and when each native was grown in interspecific competition with the exotic species, in the presence and absence of a native prairie soil community, and when nitrogen availability was elevated or was maintained at native prairie levels. We found that elevated nitrogen availability was beneficial to the exotic species and had no effect on or was detrimental to the native plant species, that the native microbial community was beneficial to the native plant species and either had no effect or was detrimental to the exotic species, and that intraspecific competition was stronger than interspecific competition for the exotic plant species and vice-versa for the natives. Our results demonstrate that soil nitrogen availability and the soil microbial community can mediate the strength of competition between native and exotic plant species. We found no evidence for native microbes enhancing the performance of the exotic plant species. Instead, loss of the native soil microbial community appears to reinforce the negative effects of elevated N on native plant communities and its benefits to exotic invasive species. Resilience of plant communities to invasion by exotic plant species is facilitated by the presence of an intact native soil microbial community and weakened by anthropogenic inputs of nitrogen.

Summary 1. A large proportion of the world's land surface is extensively managed for livestock production. In areas where livestock systems are becoming more intensive, a major challenge is to predict those plant species likely to decline, persist or increase as a result of agricultural intensification. 2. Most analyses develop inferences for frequent or abundant species, or rely on intensive studies of single species. A promising approach is to identify plant traits related to disturbance to enable inference to be made about changes in plant community composition. We used a Bayesian hierarchical model to analyse the response to agricultural intensification of 494 plant species of pastures and woodlands in southern Australia, and to identify how simple species' traits (life form, growth form and species origin) influence those responses. 3. The probability of occurrence of most species declined along the two intensification gradients, grazing intensity and soil phosphorous concentration, although the occurrence of a greater proportion of species was negatively correlated with soil phosphorous. Responses could be broadly predicted from both plant origin and plant traits, in particular growth form. 4. Native perennial geophytes, ferns and shrubs were most negatively affected by both gradients, while exotic annual grasses and forbs were more tolerant. Along the phosphorous gradient, 24 of the 30 most negatively affected plant species were native geophytes. Mean within-group responses masked considerable within- and between-species variation, particularly for the exotic species group which included species that responded both negatively and positively to intensification. 5. Synthesis and applications. The hierarchical model described here provides a powerful method for estimating individual plant responses and identifying how species' traits influence those responses. Plant species native to southern Australia are sensitive to grazing and phosphorous apparently due to a shared evolutionary history of low grazing intensity and low phosphorous soils. Invading exotic plants have faced strongly contrasting ecological filters, leading to a greater diversity of responses. Where grazing systems have been most intense, a small suite of exotics dominate. Maintaining native and functional plant diversity will necessitate limits being placed on intensive livestock management systems.

Urbanization is a process of concentration of human population in cities, which gradually transforms the natural environment. Birds, especially psittacines (macaws, parrots and parakeets), are between the most sensitive birds to the impacts produced by urbanization. But despite the wealth of the Brazilian bird fauna and the intense pace of urbanization seen in the country, little is known about the effects of this process on bird species. The objectives were: identify the resources used for food and roost by the different parrot species found in ten public squares located within the urban area of Uberlândia, MG; describe behavioral aspects of this group; and define the foraging strategies employed by parrot species in the exploration of the urban environment. The parrot species were investigated by Focal-Animal Sampling and Ad libitum Sampling. Observations were conducted from May 2011 to December 2011, in three periods comprising from sunrise to sunset. In 480 hours of observation we recorded 278 feeding events. In total, were consumed 33 plant species by four species of psittacines (Aratinga aurea, Aratinga leucophthalma, Brotogeris chiriri and Diopsittaca nobilis). These parrots showed a generalist diet. The plant families with the highest numbers of species in the parrot s diet were Fabaceae, Bignoniaceae, and Arecaceae. The food items consumed were: fruit (pulp, pulp with seed or seed), flower, nectar, and leaf. The plant species that stood out in the parrot s diet were: Terminalia catappa, Syzygium cumini, Handroanthus sp. and Livistona chinensis. The parrot species exploited a wide range of food resources in the public squares of Uberlândia, which demonstrates the importance of green areas for the maintenance of this group in the urban environment.

In response to an increasing risk of property loss from wildfires at the urban–wildland interface[…]

Urban gardens, despite their transformed nature, serve as invaluable microcosms for a quantitative examination of floral resource provision to urban pollinators, considering the plant's origin. Thus, knowledge has increased, emphasizing the importance of these green areas for hosting and conserving pollinator communities. However, there is a significant knowledge gap concerning the changing availability of these native and exotic floral resources over time and their impact on structuring interaction networks with specific pollinators. Over a year-long period, monthly surveys were conducted to record both native and exotic plant species visited by hummingbirds in an urban garden at Tlaxcala, Mexico. Flower visits were recorded, and the total flowers on each plant visited were tallied. Additionally, all observed hummingbirds were recorded during the transect walks, regardless of plant visits, to determine hummingbird abundance. The interactions were summarized using matrices, and network descriptors like connectance, specializacion, nestedness, and modularity were computed. Plant and hummingbird species in the core and periphery of the network were also identified. Lastly, simulations were performed to assess the network's resilience to the extinction of highly connected native and exotic plant species, including those previously situated in the network's core. We recorded 4,674 interactions between 28 plant species, and eight hummingbird species. The majority of plants showed an ornithophilic syndrome, with 20 species considered exotic. Despite asynchronous flowering, there was overlap observed across different plant species throughout the year. Exotic plants like Jacaranda mimosifolia and Nicotiana glauca produced more flowers annually than native species. The abundance of hummingbirds varied throughout the study, with Saucerottia berillyna being the most abundant species. The plant-hummingbird network displayed high connectance, indicating generalization in their interaction. Significant nestedness was observed, mainly influenced by exotic plant species. The core of the network was enriched with exotic plants, while Basilinna leucotis and Cynanthus latirostris played central roles among hummingbirds. Network resilience to species extinction remained generally high. Our findings provide valuable insights into the dynamics and structure of plant-hummingbird interactions in urban gardens, emphasizing the influence of exotic plant species and the network's resilience to perturbations. Understanding and managing the impact of exotic plants on such networks is crucial for the conservation and sustainable functioning of urban ecosystems.

The communities of herbivores are more frequently composed of native and exotic species. Exotic species, with a recent history of co-occurrence among them and with native species, would exhibit less resource distribution strategies than native species, which co-evolved together establishing relationships between them and their environment. Aiming to assess trophic relationships in a community of herbivores that co-occur in Ischigualasto Provincial Park, we analyzed seasonal diet compositions, trophic niche breadth and diet overlap, and made associations based on condition (native or exotic) and body size (large or small). In the hyper-arid Monte region, where the study was conducted, shrub cover was the most representative cover throughout the year. The diets of native and exotic herbivores were based on this functional group of plants. Particularly native species made intensive and sustained use of shrubs during both the wet and dry seasons. Exotic species showed higher similarity in their diets and a constant trophic niche breadth all over the year (broader than that of native species). There was less similarity among the diets of native species, and their trophic niche was narrower, particularly in the dry season. Diet overlap between natives and exotics showed no variations between seasons, not even considering species of similar body size. Probably, no important overlaps are detected in food resource use because of the low densities of exotic species currently present in Ischigualasto Provincial Park. In any event, we recommend permanent monitoring that allows assessing potential competition between native and exotic species. DOI: https://doi.org/10.25260/EA.17.27.3.0.545

Fruit consumption by birds is well reported in Brazil, but few studies compared the use of native and exotic fruit, especially in urban environment. Network Theory may be a useful tool in such studies, since it allows to evaluate multiple species of both animal and plants involved in interactions. The goals of this thesis were to evaluate bird-plant interaction networks in urban environment on regional and local scale; to assess the role of native and exotic plant species in the networks and to compare the consumers assembly interacting with native and exotic plants. We reviewed published literature on bird frugivory in urban areas of Brazil and made a meta-analysis to generate an interaction network on a regional scale. We also made observations in urban green areas of Uberlândia, Minas Gerais State in four native plant species (Matayba guianensis, Xylopia aromatica, Cecropia pachystachya e Phoradendron affine) and four exotic species (Michelia champaca, Muntingia calabura, Roystonea borinquena e Ligustrum lucidum). 320 hours of observations were carried out between May 2012 and April 2014 during morning and late afternoon. We included 15 papers in our meta- analysis in which 70 bird species consumed fruits from 15 plant species (six exotic e nine native). The bird species recorded in the greater number of papers was Tangara sayaca (n=14) and the most representative family was Tyrannidae (n=18 spp.). Bird fauna consuming native and exotic fruits were not in different groups and the interaction network on a regional scale was significantly nested (NODF=0,30; p < 0,01) but not modular (M= 0,36; p= 0,16). Two exotic plant species are part of the generalist core (region with higher interaction density) of the frugivory network in urban environment in Brazil (Ficus Microcarpa e M. champaca). At Uberlândia we recorded 540 visits with fruit consumption, performed by 31 bird species from four orders and 12 families.The most representative family was Tyrannidae (n=9 spp.) and Pitangus sulphuratus was the bird species interacting with higher plant diversity (n= 7 spp., 4 exotic e 3 native). Plant species with higher number of interactions were Xylopia aromatica (native) and Michelia champaca (exotic), both consumed by 13 bird species. A total of 339 visits were recorded on exotic plant species and 201 on native plants and 2055 fruits were consumed, 1450 native and 655 exotic fruits. Comparing native and exotic plant species there was significant difference in the number of visits (U=1018,5; p<0,05), but not in the number of fruits consumed (U=1301,50; p=0,7). Interaction network on a local scale was not significantly nested (NODF=40,11; p=0,20) nor modular (M=0,34; p=0,35). There are both native and exotic plant species on central positions of the local network and only two species comprise the generalist core, X. aromatica (native) e M. champaca (exotic). Bird assembly consuming native and exotic fruits did not form different groups. Results suggest that a relatively diverse set of birds consume fruits in urban environment in Brazil and this consumption occurs in an opportunistic way,with no preference for native or exotic plants, both on regional and local scale.

Are horses responsible for introducing non-native plants along forest trails in the eastern United States?

Lepus flavigularis is an endemic leporid from southeastern Oaxaca, México, listed as “endangered” under Mexican law and the IUCN Red List. The main threat to the species is severe habitat fragmentation due to human activities. The jackrabbit shares the grasslands with cattle (Bos taurus), but the trophic interaction between these herbivores is unknown. This study aimed to determine the seasonal diet of Lepus flavigularis and cattle, to identify the possible dietary overlap between these mammals. The study zone covers an area around the locality of Santa María del Mar in Oaxaca, southern México. Plant species were identified using linear transects, and vegetation cover was also estimated using circular plots. Throughout the study fresh L. flavigularis and B. taurus fecal samples were collected, which were processed using the microhistological technique to determine the seasonal botanical composition of diets from the two species. Twenty-three plant species were recorded in the diet of L. flavigularis and 29 species in the diet of B. taurus. Both herbivores fed primarily on Poaceae species throughout the year (L. flavigularis: dry season (ds) = 79.79 %, wet season (ws) = 91.54 %; B. taurus: ds = 78.02 %, ws = 84.63 %) despite the significant difference in the availability of plant species between seasons. No significant differences were found in the seasonal composition of the diet between the two species. Twelve plant species were consumed by both herbivores during the two seasons. The dietary overlap between the two species was high for both seasons (ds Ojk = 0.7311, ws Ojk = 0.8459). Trophic niche breadth was low for both species, with a high dietary overlap. We recorded low seasonal use values for L. flavigularis and B. taurus when compared to forage availability. Low trophic niche breadth and high dietary overlap between the two herbivores suggest forage resources competition. However, we expect that jackrabbits benefit from cattle presence, as long as the stocking rate does not increase. Furthermore, B. taurus grazing reduces height, cover, and density of vegetation, which could help L. flavigularis to avoid predators.

Abundance of White-fronted Parrots and diet of an urban parrot assemblage (Aves: Psittaciformes) in a green Neotropical city

High richness of exotic trees in tropical urban green spaces: Reproductive systems, fruiting and associated risks to native species

Urban green spaces such as gardens often consist of native and exotic plant species, which provide pollen and nectar for flower-visiting insects. Although some exotic plants are readily visited by pollinators, it is unknown if and at which time of the season exotic garden plants may supplement or substitute for flower resources provided by native plants. To investigate if seasonal changes in flower availability from native vs. exotic plants affect flower visits, diversity and particularly plant–pollinator interaction networks, we studied flower-visiting insects over a whole growing season in 20 urban residential gardens in Germany. Over the course of the season, visits to native plants decreased, the proportion of flower visits to exotics increased, and flower-visitor species richness decreased. Yet, the decline in flower-visitor richness over the season was slowed in gardens with a relatively higher proportion of flowering exotic plants. This compensation was more positively linked to the proportion of exotic plant species than to the proportion of exotic flower cover. Plant–pollinator interaction networks were moderately specialized. Interactions were more complex in high summer, but interaction diversity, linkage density, and specialisation were not influenced by the proportion of exotic species. Thus, later in the season when few native plants flowered, exotic garden plants partly substituted for native flower resources without apparent influence on plant–pollinator network structure. Late-flowering garden plants support pollinator diversity in cities. If appropriately managed, and risk of naturalisation is minimized, late-flowering exotic plants may provide floral resources to support native pollinators when native plants are scarce.

Exotic plants are a major threat to native plant diversity in Australia yet a generic model of the invasion of Australian ecosystems by exotic species is lacking because invasion levels differ with vegetation/soil type and environmental conditions. This study compared relative differences in exotic species invasion (percent cover, spp. richness) and the species richness of herbaceous native plants in two structurally very similar vegetation types, Gimlet Eucalyptus salubris and Wandoo E. capillosa woodlands in the Western Australian wheatbelt. For each woodland type, plant variables were measured for relatively undisturbed woodlands, woodlands with &amp;gt;30 years of livestock grazing history, and woodlands in road-verges. Grazed and road-verge Gimlet and Wandoo woodlands had significantly higher cover of exotic species, and lower species richness of native plants, compared with undisturbed Gimlet and Wandoo. Exotic plant invasion was significantly greater in Gimlet woodlands for both grazed (mean 78% cover) and road-verge sites (mean 42% cover) than in comparable sites in Wandoo woodlands (grazed sites 25% cover, road-verge sites 19% cover). There was no significant difference in the species richness of exotic plants between Wandoo and Gimlet sites for any of the three situations. Mean site richness of native plants was not significantly different between undisturbed Wandoo and undisturbed Gimlet woodlands. Undisturbed woodlands were significantly richer in plant species than grazed and road-verge woodlands for both woodland types. Grazed and road-verge Wandoo sites were significantly richer in plant species than communities in grazed and road-verge Gimlet. The percent cover of exotics was negatively correlated with total (native) plant species richness for both woodland types (Wandoo r = ?0.70, Gimlet r = ?0.87). Of the total native species recorded in undisturbed Gimlet, 83% and 61% were not recorded in grazed and road-verge Gimlet, respectively. This compared with 40% and 33% for grazed and road-verge Wandoo, respectively. Grazed Wandoo and grazed Gimlet sites had significantly fewer native plant species than did road-verge Wandoo and road-verge Gimlet sites. Ecosystem implications of differential invasions by exotic species, and the effects of grazing (disturbance) and other factors influencing susceptibility to exotic plant invasion (landscape, competition and allelopathy) on native species decline are discussed. Exclusion of livestock and adequate methods of control and prevention of further invasions by exotic plants are essential requirements for the conservation of these woodland systems.

Quantitative integration of factors that potentially affect exotic species richness and abundance at multiple spatial scales is relatively scarce in the literature. Our aim was to address this gap by evaluating the relative importance of the biotic community, abiotic factors, and landscape characteristics on the establishment and spread of native and exotic plant species. We assessed the effect of these factors on exotic and native species richness and abundance, and used regression tree and variation partitioning analyses to evaluate how these predictors interact to favor or limit exotic and/or native species. We found that landscape filters were especially important for the arrival of both native and exotic species, whereas biotic factors seemed to regulate the abundance of plant species once they were present within the system. However, the combined effects of different types of predictors explained the largest fraction of total variation in all models regarding exotic species. Furthermore, significant predictor variables had opposite effects on native versus exotic species at both local and landscape scales, which suggests that some ecosystem properties affect native and exotic species differently. Exotic species richness and abundance were increased by low values of native species cover and diversity, high landscape heterogeneity and edge density, human disturbances (e.g., mowing and soil disruption), land use activities (e.g., developed and agricultural areas), and proximity to transportation systems, especially highways. However, exotic species were less common in areas with low anthropogenic disturbance, where natural disturbances seemed to favor native plant species.