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How ecological interactions vary across spatial and environmental gradients has received increasing attention in recent years, contributing to the revelation of the drivers of biodiversity. However, it is still unclear how the structure of ecological interactions varies across large spatial scales and which climatic factors are associated with such variation. Here, specific predictions were derived and tested to evaluate how climatic factors and latitude are associated with the structure of bat-fruit interaction networks throughout the Neotropical region. For each study site (n = 44 sites, encompassing 48 degrees of latitude), four metrics were used to describe the network structure (i.e., network size, connectance, modularity, and nestedness). In general, an increase in modularity and a decrease in connectance and nestedness was observed towards lower latitudes and in sites with lower precipitation seasonality. Moreover, plant richness within networks increased towards lower latitudes and in sites with higher annual precipitation, whereas bat richness increased at lower latitudes and in sites with lower precipitation seasonality. These findings partially confirm both energy and seasonality hypotheses and suggest that fruit-bearing plant richness and fruit availability associated with annual precipitation and precipitation seasonality can be important correlates shaping the structure of ecological interactions throughout the Neotropical region.

Nestedness is widely observed in natural metacommunities, but its underlying mechanisms are still poorly understood. The distribution of habitats in the landscape and differences in dispersal rates of distinct insect taxa can determine the nestedness of the metacommunity. Here, we evaluated how species habitat specialization contributes to metacommunity nestedness in insect groups with different dispersal capacities in a mountaintop landscape in south-eastern Brazil. We sampled ants, butterflies and dung beetles in two main habitats, naturally fragmented forest islands and a grassland matrix (campo rupestre), during both dry and rainy seasons. We classified species according to their degree of habitat specialization (generalists or specialists) based on the relative frequencies and abundances between these two contrasting habitats. Forty of 211 species were classified as habitat specialists, seven as habitat generalists. It was not possible to classify the remaining species. The metacommunity was nested in structure, with habitat generalist species contributing more to nestedness than habitat specialists. Nonetheless, habitat distribution in the landscape did not affect the nestedness of the metacommunity. Our findings reveal that species sorting (for habitat specialists) and mass effects (for habitat generalists) are concurrent processes in the mountaintop forest–grassland mosaic. Our study helps to advance our understanding of the differences in the distribution of generalist and specialist species in a tropical mountaintop landscape and improves our ability to predict and manage the increasingly adverse effects of changes in land use and climate on metacommunities and ecosystem functions.

Butterfly species often synchronize their life cycles to seasonality, as increasing temperature and rainfall act as clues of resource availability. Nevertheless, human-made forest edges cause major changes in the microclimatic conditions that may jeopardize the synchrony between insects and favorable conditions for their emergence, conversely to natural ecotones. Here, the distribution of fruit-feeding butterflies was studied over one year in three different habitats (forest interior, forest ecotone, forest edge) to examine if: (i) species richness and abundance varies among habitats and subfamily/tribe over the year; (ii) temperature and rainfall affect the abundance and temporal distribution of species richness; and (iii) the beta diversity and its monthly partition are similar among habitats. The present study was carried out in the Rio Doce State Park, Brazil, a 36,000 ha forest reserve. In total, 11,594 individuals representing 98 butterfly species were collected. The butterflies presented a nonuniform distribution of abundance in all habitats, with greater abundance, richness and species diversity during the wet season. Butterfly abundance increased with high temperatures in all habitats. The contribution of species turnover and nestedness varied over the months, overlapping with the seasonal changes. Understanding how rates of species turnover vary over time in different habitats can help explain the vulnerability of species to environmental changes, allowing comparison of assemblages over time.

The impact of storms on coastal dunes and beaches and the effects they induce in topography and plant communities are natural processes that contribute to maintaining natural coastal dynamics. However, because coasts are often densely populated, these phenomena are perceived as major threats to human property. To protect human assets sustainably, nature-based defenses have emerged as an option. Coastal dunes act as natural buffers that mitigate the extent of erosion and inland flooding, and their resistance depends on the biogeomorphological feedback between the plants and the dunes. This study aimed to evaluate the effect of one winter storm on beach and dune topography and the plant communities, and to explore the effect of plants in mitigating erosion on beaches with different geomorphological features. The effects on plant communities were evaluated by comparing diversity and plant cover before and after the storm. Later, the role of plants in conferring dune resistance against erosion was examined by measuring erosion on the exposed face of the dunes considering plant cover and plant richness. The results did not show significant differences in plant diversity and plant cover between pre-and post-storm conditions, but turnover of species was recorded. The dune building species were not affected but inland species disappeared. Erosion was reduced when the dunes were higher and, furthermore, plant cover was negatively correlated with erosion on these dunes. The results showed a reduced impact of the storm on the plant communities, which is important as it facilitates the recovery of dunes by the dune-building species and protects them in a subsequent storm. The novelty of this study is that: (a) it demonstrates the species-specific role of plants in mitigating dune erosion in field conditions; (b) it shows the interaction between plant-related features and geomorphological variables in promoting dune resistance to erosion, and (c) it explores the immediate effect of a winter storm on the plant community and dune-building species.

Coastal erosion is a natural process, whose intensity and occurrence have increased due to natural and anthropogenic factors. To protect the coasts, the use of hard infrastructure is a widespread practice that can be effective, mostly at a local scale. However, recent evidence also shows that downstream erosion can be accelerated in adjacent zones. Because of this, natural barriers such as coastal dunes and their plant cover have gained attention, but there is a general lack of information about the role that different species (and combinations of species) play in coastal protection. The aim of this study was to explore if the functional richness of plant species helps reduce wave erosion on embryo coastal dunes. In a wave flume, we set up a 1:1 scale artificial dune covered with different combinations of plant species (Ipomoeae pes-caprae, Sesuvium portulacastrum, and Sporobolus virginicus) and exposed it to simulated “storm waves”. We found that erosion was reduced in dunes covered by plants, but such protection was species-specific and the effectiveness of protection varied over time. Ipomoea was the most effective specie for protection. Differences between species and combinations of species were associated with their physical attributes such as growth form and plant architecture. Although we found that there are species that offer little or no protection from hydrodynamic forces, they may still be important for coastal protection through their ability to build embryo dunes through eolian processes. Indeed, nature-based coastal protection is likely to be an effective alternative to engineered solutions at many sites, but the protection provided is species-specific.

Herbivory is ubiquitous. Despite being a potential driver of plant distribution and performance, herbivory remains largely undocumented. Some early attempts have been made to review, globally, how much leaf area is removed through insect feeding. Kozlov et al., in one of the most comprehensive reviews regarding global patterns of herbivory, have compiled published studies regarding foliar removal and sampled data on global herbivory levels using a standardized protocol. However, in the review by Kozlov et al., only 15 sampling sites, comprising 33 plant species, were evaluated in tropical areas around the globe. In Brazil, which ranks first in terms of plant biodiversity, with a total of 46,097 species, almost half (43%) being endemic, a single data point was sampled, covering only two plant species. In an attempt to increase knowledge regarding herbivory in tropical plant species and to provide the raw data needed to test general hypotheses related to plant–herbivore interactions across large spatial scales, we proposed a joint, collaborative network to evaluate tropical herbivory. This network allowed us to update and expand the data on insect herbivory in tropical and temperate plant species. Our data set, collected with a standardized protocol, covers 45 sampling sites from nine countries and includes leaf herbivory measurements of 57,239 leaves from 209 species of vascular plants belonging to 65 families from tropical and temperate regions. They expand previous data sets by including a total of 32 sampling sites from tropical areas around the globe, comprising 152 species, 146 of them being sampled in Brazil. For temperate areas, it includes 13 sampling sites, comprising 59 species. Thus, when compared to the most recent comprehensive review of insect herbivory (Kozlov et al.), our data set has increased the base of available data for the tropical plants more than 460% (from 33 to 152 species) and the Brazilian sampling was increased 7,300% (from 2 to 146 species). Data on precise levels of herbivory are presented for more than 57,000 leaves worldwide. There are no copyright restrictions. Please cite this paper when using the current data in publications; the authors request to be informed how the data is used in the publications.

Arbuscular-mycorrhizal (AM) fungi affect individual plants and the diversity of plant communities. AM interactions are sensitive to the physical properties and nutrient availability of soil. In contrast to the comprehensive knowledge of AM fungi's diversity in many mainland ecosystems, there is a considerable gap in the understanding of the communities of AM fungi on oceanic islands. We surveyed the community of AM fungi in the wet forests of Socorro Island (above an elevation of 600 m). Because of the influence of northerly winds, the island's windward side is presumably more humid than the leeward side, although, above 600 m elevation, fog is common on both sides of the island. Forty-six percent of AM fungi species occurred on only one side of the island. Also, four species common to both sides showed marked differences in abundance, and the abundances of the AM fungi correlated with the abundance of plant life-forms. Beta diversity was similar in the southern and northern forests. However, the contribution of nestedness to beta diversity was three-fold greater in the southern forests than in the northern forests. Root colonization by AM fungi was higher in the northern forests, where phosphorous content was also high. The prevalence of nestedness in beta diversity and the lower mycorrhizal colonization of roots in the southern forests could reflect known perturbations in the southern forests.

Made available in DSpace on 2021-06-25T12:26:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Social wasps participate in food webs, act as biological control agents in small crops and the natural environment, and act as potential pollinators. The objective of this study was to carry out an inventory of social wasps in five phytophysiognomies with different degrees of anthropogenic disturbance in Sao Paulo, Brazil. The collections were performed by active search and attractive traps to survey social wasps. We collected wasp for one year with collection campaigns every other month totaling six campaigns for site. We collected a total of 913 individuals representing 31 species and eight genera. The species with the highest abundances were Agelaia pallipes and Agelaia vicina. The highest richness of social wasps was found in the riparian forest and regenerating Cerrado. We conclude that social wasp richness and diversity varies according to habitat vegetation characteristics and that these effects are likely mediated by resulting differences in the provision of resources and nesting locations among the different environments. The areas in this study have suffered considerable vegetation loss due to common farming practices, however, the existing fragments are still capable of hosting a rich social wasp fauna. Univ Estadual Paulista, Inst Biociencias, Dept Zool, 24 A 1515, BR-13506752 Rio Claro, SP, Brazil INECOL, Inst Ecol AC, Red Biol Evolut, Xalapa, Veracruz, Mexico Museu Paraense Emilio Goeldi, Campus Pesquisas, Belem, Para, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Zool, 24 A 1515, BR-13506752 Rio Claro, SP, Brazil

In this chapter we examine how the current patterns of anthropogenic impact on biodiversity are engendering a pulse of animal life loss – defaunation – with emphasis on the decline and massive extinction of populations of mammals. Given that many species of this group operate as herbivores and, due to their local abundance in some regions and ecosystems of the world, have the potential to affect plant performance and survival, their decline or outright local extinction significantly disrupt the patterns of mammalian herbivory, in some cases causing the local extinction of this critical interaction affecting the structure and composition of communities and ecosystems. Our chapter, addressing a different group of herbivores than that examined in the other chapters of the volume, as well as addressing species interactions in defaunated systems, includes an analysis of mammalian herbivores in the context of insect herbivores, a historical account of the development and evolution of defaunation science, and a discussion of the methods available to document defaunation. (We hope that the inclusion of such contextual analysis and historical and methodological accounts will be of some use for the readers who are not familiar with this field.) This is followed by a brief expose of the disruption of mammalian herbivory and its consequences at the community and ecosystem levels.

Functional diversity is a key concept to understand how plants respond to selective pressures and how they influence ecosystem processes. Although there is empirical information about the variation of the functional traits of plants in environmental gradients, their use to understand their biotic interactions has been little explored. Currently, novel proposals for the analysis of the plant-herbivore interactions integrating the study of functional traits have been put forward. This approach can help to generate projection models about the effect of herbivory on ecosystem processes under different environmental scenarios. In this chapter we present a review of the concept of functional diversity in plants and their application in herbivory studies, through the use of syndromes and their ecological and evolutionary implications. In addition, we propose some lines of research that can help build a comprehensive framework to relate the functional responses of plants and defense theories, as well as determine the biotic and abiotic factors that regulate herbivory and its impacts on ecosystem processes.

Made available in DSpace on 2020-12-10T19:45:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fire is one of the most common natural harassments and it is characterized as an important component of the systems, although little studied regarding the influence of this event in social wasps communities. One month after the end of the collections, the area of Regenerating Brazilian Savanna of the present study undertook a fire in exactly half of the points sampled, which motivated one further year of sampling. The aim of this study was to compare the social wasps fauna collected before and after the fire, indicating a possible impact on their populations. In the first year of collection, before the fire, 21 species (seven genera) were sampled with a total amount of 297 individuals. In the second year, after the fire, 14 species were collected (reduction of 33,33% in richness) and six genera, with an abundance of 153 wasp individuals of Vespidae (loss of 48,48% of individuals). The area 1 in the first year, presented an abundance of 182 individuals (61,27%) and 16 species (76,19%) and the area 2, 115 (38,73%) and 19 species (90,47%). For the area 1 in the second year, 74 individuals (48,36%) and 12 species (85,71%) were captured and for the area 2 there were 79 individuals (51,64%) distributed among nine species (64,28%). However, we did not find significant values for both the abundance and for the richness among the areas and the years of sampling. Nine species were not registered in the second year, although two presented their registration only after the fire. Univ Estadual Paulista, Inst Biociencias, Zool Dept, Rio Claro, SP, Brazil Ctr Univ Herminio Ometto Uniararas, Araras, SP, Brazil Inst Ecol AC, INECOL, Red Biol Evolut, Xalapa, Veracruz, Mexico Museu Paraense Emilio Goeldi, Coordenacao Zool, Campus Pesquisas, Belem, Para, Brazil Univ Fed Mato Grosso do Sul, Ctr Ciencias Biol & Saude, Programa Pos Grad Ecol & Conservacao, Campo Grande, MS, Brazil Univ Estadual Paulista, Inst Biociencias, Zool Dept, Rio Claro, SP, Brazil

Background. In arid environments plants face aridity and herbivory, therefore it has been proposed that both are convergent selective forces. However the drivers of insect herbivory in these ecosystems remain poorly understood. Question. Does insect herbivory vary in two plant associations subject to different levels of aridity? To what extent differences in herbivory are determined either by foliar traits, or predation by birds? Study species. Citharexylum tetramerum, Viguiera pinnatilobata, and Solanum tridynamum. Study site. We compared two-plant associations: the mezquital with a closed canopy and wettest conditions and the tetechera a dry place with an open canopy at the Zapotitlán Valley, México. Methods. We evaluated leaf traits (N, C, water content, leaf strength and trichomes), herbivore insects abundance and the effects on herbivory when some predators are excluded. Results. Herbivory was higher in the drier site (tetechera) than in the more humid one (mezquital) in one year but not in the second one. In both plant associations herbivory increased when predators of herbivores were excluded. Plants in mezquital had more water and nitrogen content than plants in tetechera. The later had higher carbon concentration and carbon:nitrogen ratio, leaf strength and density of trichomes. Abundance of herbivore insects and insect predation were higher in the most arid site. Conclusions. Our results show that insect herbivory increases in the most arid site and that predation by birds plays a role as a driver of herbivory, while resistance to aridity seems to be the main driver of leaf structural characteristics.

Recovery planning is an important global conservation strategy for threatened species. Despite the existence of international standards for recovery planning, deficiencies and anomalies have been detected in several jurisdictions. This study evaluated the quality of recovery plans based on internal consistency as a measurement of coherent planning. We analyzed 236 plans developed by the Australian Government (1992–2006) using three criteria: (a) consistency of gaps in scientific information with prescribed research actions, (b) consistency of identified threats with prescribed threat abatement actions and (c) consistency of established plan objectives with performance evaluation criteria. These criteria were aggregated in order to calculate an index of plan consistency. We tested two hypotheses: (1) plans made for single-species would exhibit better consistency than those for multi-species; and (2) plans made under the amended legislation of the Environment Protection and Biodiversity Conservation Act (EPBCA) would exhibit better consistency than those under the rescinded Endangered Species Protection Act (ESPA). In total, over 85% of the plans consistently addressed the research needs. However, the plans addressed threats poorly (66% of all plans exhibited inconsistencies). Moreover, nearly 50% of all plans established inconsistent performance evaluation criteria. Under the ESPA, single- and multi-species plans exhibited equal consistency, but under the EPBCA, single-species plans clearly exhibited higher consistency. Our major contribution is the assessment of attributes of consistency that are paramount for effective recovery planning. Evaluation of these attributes may provide knowledge of universal utility and relevance to other biodiversity conservation efforts.

Mexico is one of the most biodiverse countries in the world, with an important proportion of endemism mainly because of the convergence of the Nearctic and Neotropical biogeographic regions, which generate great diversity and species turnover at different spatial scales. However, most of our knowledge of the Mexican ant biota is limited to a few well-studied taxa, and we lack a comprehensive synthesis of ant biodiversity information. For instance, most of the knowledge available in the literature on Mexican ant fauna refers only to species lists by states, or is focused on only a few regions of the country, which prevents the study of several basic and applied aspects of ants, from diversity and distribution to conservation. Our aims in this data paper are therefore (1) to compile all the information available regarding ants across the Mexican territory, and (2) to identify major patterns in the gathered data set and geographic gaps in order to direct future sampling efforts. All records were obtained from raw data, including both unpublished and published information. After exhaustive filtering and updating information and synonyms, we compiled a total of 21,731 records for 887 ant species distributed throughout Mexico from 1894 to 2018. These records were concentrated mainly in the states of Chiapas (n = 6,902, 32.76%) and Veracruz de Ignacio de la Llave (n = 4,329, 19.92%), which together comprise half the records. The subfamily with the highest number of records was Myrmicinae (n = 10,458 records, 48.12%), followed by Formicinae (n = 3,284, 15.11%) and Ponerinae (n = 1,914, 8.8%). Most ant records were collected in the Neotropical region of the country (n = 12,646, 58.19%), followed by the Mexican transition zone (n = 5,237, 24.09%) and the Nearctic region (n = 3,848, 17.72%). Native species comprised 95.46% of the records (n = 20,745). To the best of our knowledge, this is the most complete data set available to date in the literature for the country. We hope that this compilation will encourage researchers to explore different aspects of the population and community research of ants at different spatial scales, and to aid in the establishment of conservation policies and actions. There are no copyright restrictions. Please cite this data paper when using its data for publications or teaching events.

Insect-aroid interaction studies have focused largely on pollination systems, however, few report trophic interactions with other herbivores. This study features the endophagous insect community in reproductive aroid structures of a tropical rainforest of Mexico, and the shifting that occurs along an altitudinal gradient and among different hosts. In three sites of the Los Tuxtlas Biosphere Reserve in Mexico, we surveyed eight aroid species over a yearly cycle. The insects found were reared in the laboratory, quantified and identified. Data were analyzed through species interaction networks. We recorded 34 endophagous species from 21 families belonging to four insect orders. The community was highly specialized at both network and species levels. Along the altitudinal gradient, there was a reduction in richness and a high turnover of species, while the assemblage among hosts was also highly specific, with different dominant species. Our findings suggest that intrinsic plant factors could influence their occupation, and that the coexistence of distinct insect species in the assemblage could exert a direct or indirect influence on their ability to colonize such resources.

International audience; The positive effect of earthworms on soil processes and plant growth has been extensively documented. The capacity of earthworms to decompose organic matter has been attributed to the microbial communities that inhabit their digestive track or the structures they build, which in turn contribute to make up the drilosphere, a hotspot for microbial activity. However, how earthworms modify the structure of soil microbial communities and how these changes affect soil microbial processes is still unclear. Do earthworms reduce microbial abundance and activity because they feed on microorganisms or do they select and stimulate specific microbial groups? We hypothesise that “the effect of earthworms on nutrient cycling and plant growth is not only a direct effect but is mainly mediated indirectly, via modifications of the microbial community.” The objective of this review is to synthesize the existing literature concerning the influence of earthworms on the structure and function of soil microbial communities, as well as to understand how earthworm-induced changes in the soil microbiota would in turn impact soil processes, particularly those occurring in the rhizosphere and involved in plant growth and health. Recent reports have shown that specific bacterial groups consistently increase in soils where earthworms are present, regardless of the earthworm functional group. The extent of this increase seems to be dependent upon the type of substrate under study. Our synthesis also reveals that endogeic and anecic earthworms regularly induce an increase in soil nutrients, whilst this positive effect is not as evident in the presence of epigeic earthworms. The effect of earthworms on nutrient cycling has been further investigated with microbial functional genes, although existing reports largely focus on nitrogen cycling. Earthworms seem to enhance denitrification, most likely through the increase in organic compounds due to organic matter decomposition. By enhancing soil nutrient availability, earthworms indirectly promote plant growth, which has also been attributed to the induction of signal molecules. However, no experiment to date has been able to prove a direct causal relationship between specific signal molecules, earthworms and plant growth promotion. Finally, we propose a framework for earthworm-microbiota interactions and recommend further research.

A set of species, not linked by close ancestry, with similar functional responses to selective pressures, is known as a functional group or response syndrome. Some studies have investigated antiherbivore plant defenses in the context of defense syndromes, with contrasting results. We analyze how the assembly of leaf-functional traits and wood density can explain insect herbivory in 69 woody species in a tropical rain forest in southern Mexico. In addition, we used a phylogenetic hypothesis to address whether the observed syndromes were at least in part driven by ancestry. Three functional groups of woody plants were detected and related to 1) low nutritional quality, 2) resistance, and 3) tolerance to herbivory. Herbivory tolerant species presented the highest damage by herbivores, which is concordant with theoretical expectations and other empirical observations. In contrast, herbivory in the defensive resistance and low nutrition syndromes were 35 % and 55 % lower than in herbivory tolerant species, respectively. Taxa in the defensive resistance syndrome were significantly clustered based on the net relatedness index (NRI) and the nearest taxon index (NTI). In contrast, in the other two syndromes, the NRI showed a random structure but opposed deviations from random expectations in the NTI. Taxa in the low nutritional quality syndrome were over-dispersed in the phylogeny, while tolerant species appeared clustered. This evidence suggests that the low nutritional quality syndrome may represent the ancestral antiherbivore defense of woody plants in the tropical rain forest. In contrast, the tolerance and defensive resistance syndromes included clades of recent diversification.

Fil: Villada Bedoya, Sebastián. Universidad de Caldas. Grupo de Investigación en Biodiversidad y Recursos Naturales; Colombia. Fil: Cultid Medina, Carlos Andrés. Universidad de Caldas. Grupo de Investigación en Biodiversidad y Recursos Naturales; Colombia. Fil: Cultid Medina, Carlos Andrés. Universidad del Valle. Grupo de Investigación en Biología, Ecología y Manejo de Hormigas; Colombia. Fil: Cultid Medina, Carlos Andrés. Wildlife Conservation Society; Colombia. Fil: Cultid Medina, Carlos Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fil: Escobar, Federico. Consejo Nacional de Ciencia y Tecnología. Instituto de Ecología A. C.; México. Fil: Guevara, Roger. Consejo Nacional de Ciencia y Tecnología. Instituto de Ecología A. C.; México. Fil: Zurita, Gustavo Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico (Nordeste). Instituto de Biología Subtropical; Argentina. Fil: Zurita, Gustavo Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico (Nordeste). Instituto de Biología Subtropical. Nodo Puerto Iguazú; Argentina. Fil: Zurita, Gustavo Andrés. Universidad Nacional del Nordeste. Instituto de Biología Subtropical; Argentina. Fil: Zurita, Gustavo Andrés. Universidad Nacional del Nordeste. Instituto de Biología Subtropical. Nodo Puerto Iguazú; Argentina. In landscapes dominated by agriculture, conspicuous edges often occur between landscape elements. However, there is disagreement about the existence and intensity of edge effects, and information about species‐specific responses remains scarce. Studying such edge effects can help elucidate functional landscape connectivity and contribute to agricultural management. We, therefore, assessed whether sun‐grown coffee represents a barrier to dung beetles in an Andean agricultural landscape. We also evaluated whether the response to edge effects differs among species. We found that diversity and abundance tend to decrease from forest to sun‐grown coffee and that there are sharp increases in species turnover at the forest–coffee edge. We detected several different species‐specific responses to the forest–coffee edge, suggesting differences in the mobility of the species (or spillover) and in the degree of penetration that takes place from forest patches to sun‐grown coffee plantations. This study demonstrates that the sun‐grown coffee matrix constitutes a barrier to forest species and suggests that the forest–coffee ecotone is more complex than expected. Our results support the notion that the conservation value of native forest patches in agricultural scenarios depends on the functional connectivity of forest units in the landscape to maximize the opportunities species have to disperse through the agricultural matrix.

The study of morphological variation in heterogeneous environments provides evidence for understanding processes that determine the differences between species and interspecific adaptive strategies. In 14 populations of two closely related cycads from the genus Zamia (Zamia loddigesii and Z. prasina), the phenotypic variation was analyzed based on 17 morphological traits, and this variability was correlated with environmental conditions across the populations. Despite the significant inter-population variation observed in the two species, greater inter-specific differences were observed based on generalized linear models. Individuals of all populations except for the Macuspana (Tabasco) population of Z. prasina were separated into two discrete groups in a multivariate space (non-metric multidimensional scaling). Macuspana plants overlapped marginally with the multivariate space defined by plants in the four Z. loddigesii populations. Remarkably, Macuspana is geographically located at the distribution limits of both species that occur in close proximity expressing traits that resemble either of the two species. The heterogeneous environment seems to play a determining role in the phenotypic expression of both species. The variation found could be related to the local ecological adaptions that tend to maximize the populations adaptation.

Ecological invasions are a major issue worldwide, where successful invasion depends on traits that facilitate dispersion, establishment, and population growth. The nonnative succulent plant Kalanchoe pinnata, reported as invasive in some countries, is widespread in remnants of seasonally dry tropical forest on a volcanic outcrop with high conservation value in east‐central Mexico where we assessed its mating system and demographic growth and identified management strategies. To understand its local mating system, we conducted hand‐pollination treatments, germination, and survival experiments. Based on the experimental data, we constructed a life‐stage population matrix, identified the key traits for population growth, weighted the contributions of vegetative and sexual reproduction, and evaluated management scenarios. Hand‐pollination treatments had slight effects on fruit and seed setting, as well as on germination. With natural pollination treatment, the successful germination of seeds from only 2/39 fruit suggests occasional effective natural cross‐pollination. The ratios of the metrics for self‐ and cross‐pollinated flowers suggest that K. pinnata is partially self‐compatible. Most of the pollinated flowers developed into fruit, but the seed germination and seedling survival rates were low. Thus, vegetative propagation and juvenile survival are the main drivers of population growth. Simulations of a virtual K. pinnata population suggest that an intense and sustained weeding campaign will reduce the population within at least 10 years. Synthesis and applications. The study population is partially self‐compatible, but sexual reproduction by K. pinnata is limited at the study site, and population growth is supported by vegetative propagation and juvenile survival. Demographic modeling provides key insights and realistic forecasts on invasion process and therefore is useful to design management strategies.

Phylogenetic information provides insight into the ecological and evolutionary processes that organize species assemblages. We compared patterns of phylogenetic diversity among macromycete and woody plant communities along a steep elevational gradient in eastern Mexico to better understand the evolutionary processes that structure their communities. Macrofungi and trees were counted and identified in eight sites from 100 to 3500 m asl, and sequence data retrieved from GenBank for the same or closely related species were used to reconstruct their phylogenies. Patterns of species richness and phylogenetic diversity were similar for both macrofungi and trees, but macromycete richness and diversity peaked at mid-elevations, whereas woody plant richness and diversity did not show significant trends with elevation. Phylogenetic similarity among sites was low for both groups and decreased as elevational distance between sites increased. Macromycete communities displayed phylogenetic overdispersion at low elevations and phylogenetic clustering at high elevations; the latter is consistent with environmental filtering at high elevation sites. Woody plants generally exhibited phylogenetic clustering, consistent with the potential importance of environmental filtering throughout the elevational gradient.

Concurrent interactions and the availability of resources (e.g., light) affect the cost/benefit balance during mutualistic and antagonistic interactions, as well as plant resource allocation patterns. Mycorrhizal interactions and herbivory concur in most plants, where mycorrhizae can enhance the uptake of soil nutrients by plants as well as consuming a large fraction of the plant's carbon, and defoliation usually reduces light interception and photosynthesis, thereby causing direct losses to the hosts of mycorrhizal fungi. Both types of interactions affect the carbon budget of their host plants and thus we predict that the relative costs of herbivory and mycorrhizal colonization will increase when photosynthesis is reduced, for instance in light limited environments. We conducted a greenhouse experiment using Datura stramonium to investigate the effects of defoliation and mycorrhizal inoculation on the resource allocation patterns in two different light environments. Defoliated plants overcompensated in terms of leaf mass in both light environments, but total seed mass per fruit was negatively affected by defoliation in both light environments. Mycorrhizal inoculation had a positive effect on vegetative growth and the leaf nitrogen content, but defoliation negates the benefit of mycorrhizal interactions in terms of the leaf nitrogen content. In general, D. stramonium compensated for the relative costs of concurrent mycorrhizal interactions and defoliation; plants that lacked both interactions exhibited the same performance as plants with both types of interactions.

While arbuscular mycorrhizal fungi improve plant performance they demand large shares of the plant's assimilated carbon, therefore resource allocation trade-offs may drive the commonly observed sexual dimorphism in mycorrhizal colonization in dioecious species. Here we looked for evidence of the evolutionary reduction of mycorrhizal colonization in males of 15 tropical rain forest plants including palms (Chamaedorea) and trees, light-demanding and shade-tolerant species. For none of the analyzed species there was evidence of spatial segregation of the sexes. Most of the tree species had no seasonal variability in mycorrhizal colonization and males had lower mycorrhizal colonization than females in over 70% of the tree species. In contrast, there were no differences between the sexes of the Chamaedorea species. Chamaedorea species had ticker roots and lower specific root length than trees, and seasonal patterns of mycorrhizal colonization correlated with the life-histories of the plants. Based on phylogenetically independent contrast, mycorrhizal colonization of male trees correlated negatively with a metric of sexual differentiation of mycorrhizal colonization between sexes. Our results suggest an evolutionary reduction in the intensity of mycorrhizal interactions in male plants, presumably driven by resource allocation trade-offs as the origen of sexual dimorphs in mycorrhizal colonization.

Rodents are known to perform post-dispersal seed predation in tropical rain forest, but there is little information on the identity of these seed predators and how they select their seeds. Using cafeteria experiments, we found that seed mass, rodent body mass, and the ratio of seed/rodent mass were determinants of seed consumption.

Species that are strong interactors play disproportionately important roles in the dynamics of natural ecosystems. It has been proposed that their presence is necessary for positively shaping the structure and functioning of ecosystems. We evaluated this hypothesis using the case of the world's largest parrotfish (Bolbometopon muricatum), a globally imperiled species. We used direct observation, animal tracking, and computer simulations to examine the diverse routes through which B. muricatum affects the diversity, dis- persal, relative abundance, and survival of the corals that comprise the foundation of reef ecosystems. Our results suggest that this species can influence reef building corals in both positive and negative ways. Field observation and simulation outputs indicated that B. muricatum reduced the abundance of macroalgae that can outcompete corals, but they also feed directly on corals, decreasing coral abundance, diversity, and colony size. B. muricatum appeared to facilitate coral advancement by mechanically dispersing coral fragments and opening up bare space for coral settlement, but they also damaged adult corals and remobilized a large volume of potentially stressful carbonate sediment. The impacts this species has on reefs appears to be regulated in part by its abundance—the effects of B. muricatum were more intense in simulation scenarios populated with high densities of these fish. Observations conducted in regions with high and low predator (e.g., sharks) abundance generated results that are consistent with the hypothesis that these predators of B. muricatum may play a role in governing their abundance; thus, predation may modulate the intensity of the effects they have on reef dynamics. Overall our results illustrate that functionally unique and threatened species may not have universally positive impacts on ecosystems and that it may be necessary for environmental managers to consider the diverse effects of such species and the forces that mediate the strength of their influence.

The capacity of organisms to change their sex has evolved independently in several plant and animal lineages. Sex change has been widely studied, but research approaches have differed for plants and animals, and conclusions have often been taxon-specific. Although sex allocation theory provides a unifying framework for the study of sex change, this unity has not always been appreciated, especially in the botanical literature. Here, we review sex change with regard to its representation in relation to taxonomy and other sexual systems, with regard to its suggested adaptive benefits, and to the role of taxon-specific body architecture, such as modularity and gonadal structure. We highlight differences and similarities between plants and animals and suggest promising lines of future research.

We analyzed the influence of humidity, temperature, and temporal and elevational distribution on the composition, abundance, and richness of rove beetle assemblages captured with carrion traps in a Quercus L. forest, Cerro de Garcia, Jalisco, Mexico. Four sites with elevations ranging 2,100–2,700 m were surveyed. Beetles were captured monthly from September 2013 to August 2014. Three carrion traps were set at each sampling site, separated by 100 m distance. At each site, a data-logger was used to record temperature and humidity. In total, 18,054 rove beetles were captured, belonging to nine subfamilies, 11 tribes, 33 genera, and 75 species. The rove beetle assemblage showed the highest diversity during the rainy season (q = 0, 1 and 2) and the lowest during the dry season. The composition of the assemblage at 2,700 m elevation was mainly influenced by humidity and at 2,100 m by temperature. Beta diversity in the Quercus forest at different elevations and collecting periods was best explained by species replacements (shifts), and the interaction of humidity and temperature.

Oceanic islands are simplified ecosystems, which are very useful for understanding the processes related to the structuring of natural communities and for assessing cascade effects after perturbations. Socorro Island in the Pacific Ocean reaches up to 1040 m in elevation, and the northeastern side that faces trade winds is more humid than the leeward southwestern side. Apparently, the lack of freshwater throughout most of the island has prevented the spread of invasive cats and sheep to the north, but these species have severely impacted land bird communities on the southern side, where they have potentially disrupted functions such as the top-down control of herbivory. We tested the relative importance of bottom-up (soil and foliage nutrient availability) and top-down (predation of insect herbivores) drivers of herbivory in three endemic tree species. By experimentally excluding birds, we assessed changes in herbivory when top-down control was disrupted, and we also evaluated herbivore predation rates using artificial caterpillars. Our findings suggest that the herbivory patterns on Socorro Island are driven by the top-down control of herbivores by land birds, because their exclusion resulted in higher herbivory (12%) despite low nitrogen content (bottom-up control) of leaves on the north side, whereas the leaves were richer in nitrogen on the south side but no change in herbivory was observed when birds were excluded, and overall, herbivory was 30% higher than in the north, suggesting release of herbivores from top down control on the south side, probably due to effects of invasive predators (cats) or sheep, which may have reduced suitable bird habitats. A better understanding of how drivers of ecological interactions operate on Socorro Island may increase the likelihood of success of future restoration programs.

Overhunting has caused severe decline or local extinction in many large-bodied mammals with direct consequences on plant regeneration, yet little is known about indirect impacts of selective defaunation on commensal species. Cascading effects of species extinction across dependent species groups are likely to occur in coprophagous beetles, because these invertebrates rely on mammal dung for food and nesting material. Both mammals and dung beetles provide important ecosystem services and cascading effects are likely to lead to rapid functional losses. In this study, we described changes in dung beetle communities across a gradient of selective defaunation in continuous Brazilian Atlantic rain forest. We compared the dung beetle assemblages in seven sites with different mammalian biomass and composition. The reduction in the mammalian biomass had a major effect on dung beetle communities by (1) increasing dung beetle abundance with decreasing overall mammal, primate and large mammal biomasses, (2) decreasing dung beetle species richness with decreasing overall mammal biomass and (3) decreasing dung beetle size with decreasing large mammal biomass. Moreover, our study demonstrated the importance of the composition of mammal communities in structuring dung beetle communities. This study documented how selective changes in mammalian biomass and composition affect dung beetle species communities, which in turn may have cascading consequences for the ecosystem. Since most of tropical ecosystems are facing dramatic changes in mammalian composition, it is urgent to evaluate the functional losses associated with such co-extinctions.

One of the most intriguing questions in ecology is how to identify which and how many species will be able to inhabit human-modified landscapes. Large-bodied mammals structure plant communities by trampling, herbivory, seed dispersal and predation, and their local extinction may have pervasive consequences in plant communities due to the breakdown of key interactions. Although much attention has been given to understanding the effects of defaunation on plant communities, information on the potential impacts on plant functional groups (seed dispersal, seed size and seedling leaves defense) inhabiting continuous forests after defaunation is scarce. We conducted mammal surveys (line transects and camera trapping) to determine the defaunation status of a continuous Atlantic forest in Brazil. Then, we evaluated the effects of defaunation on seedling diversity, richness and abundance of functional groups using 15 plot-pairs (each pair with one open and one exclusion plot) monitored over 36 months. We found that the studied area is partially defaunated because it exhibits high abundance of primates, while terrestrial mammals, such as large rodents and ungulates, are rare. We found no significant changes in either seedling richness and diversity or in the seedling composition of plant functional groups in response to mammal exclosure. Seedling mortality and recruitment were similar between plot types. Our findings suggest that at semi-defaunated areas, where arboreal species are still present, terrestrial mammals have low impacts on the plant community reassembly.

Positive density-dependent seed and seedling predation, where herbivores selectively eat seeds or seedlings of common species, is thought to play a major role in creating and maintaining plant community diversity. However, many herbivores and seed predators are known to exhibit preferences for rare foods, which could lead to negative density-dependent predation. In this study, we first demonstrate the occurrence of increased predation of locally rare tree species by a widespread group of insular seed and seedling predators, land crabs. We then build computer simulations based on these empirical data to examine the effects of such predation on diversity patterns. Simulations show that herbivore preferences for locally rare species are likely to drive scale-dependent effects on plant community diversity: at small scales these foraging patterns decrease plant community diversity via the selective consumption of rare plant species, while at the landscape level they should increase diversity, at least for short periods, by promoting clustered local dominance of a variety of species. Finally, we compared observed patterns of plant diversity at the site to those obtained via computer simulations, and found that diversity patterns generated under simulations were highly consistent with observed diversity patterns. We posit that preference for rare species by herbivores may be prevalent in low- or moderate-diversity systems, and that these effects may help explain diversity patterns across different spatial scales in such ecosystems.

Gradient analysis is rarely used in studies of fungal communities. Data on macromycetes from eight sites along an elevation gradient in central Veracruz, Mexico, were used to demonstrate methods for gradient analysis that can be applied to studies of communities of fungi. Selected sites from 100 to 3,500 m altitude represent tropical dry forest, tropical montane cloud forest, conifer forest, and their ecotones. From May to October 2010, macromycetes were collected monthly within ten 10 × 10 m permanent plots per site. In total, 672 individuals of 213 species of macromycetes were recorded. Models for richness and diversity for all macromycete and ectomycorrhizal communities displayed peaks in the mid-part of the gradient, and a tendency to increase with elevation, whereas xylophagous fungi displayed a peak in the mid-lower part but tended to decrease with elevation. Cluster and Maximum Likelihood analyses distinguished four communities for both macromycetes and trees, but plant and fungal communities were only partly concordant. Canonical correspondence analysis indicated that macromycete distribution along the gradient is related to slope, relative humidity, soil temperature, soil water content, canopy openness, and litter depth. Spearman’s correlation and regression trees suggested that air and soil temperature, relative humidity, soil water content, canopy openness, vegetation structure and tree species richness were most strongly related to macrofungal functional groups, but these environmental variables were often correlated to the forest type and may not be causal. Variation in the environment along the elevation gradient differentially affected macromycete functional groups. Results from the different methods used in this work were concordant and showed significant patterns.

We examined the consequences of habitat fragmentation on the assemblage of floral visitors and pollinators to male- and female-phase inflorescences of the understorey dominant palm Astrocaryum mexicanum at the Los Tuxtlas tropical rain forest. In six forest fragments ranging from 2 to 700 ha, we collected all floral visitors, pollinators and non-pollinators, to male- and female-phase inflorescences at the time of their greatest activity. We used multivariate and mixed-effects models to explore differences in guild composition between sexual phases of inflorescences and the effects of forest fragment size on several metrics of the assemblages of floral visitors. We detected 228 786 floral visitors, grouped into 57 species, across the six forest fragments. On average, abundance and species richness of floral visitors to female-phase inflorescences were higher than to male-phase ones. Forest fragmentation had no effect on species richness but negatively affected Shannon's diversity index. Overall, the most abundant species of floral visitors were predominantly found in inflorescences of plants from the large fragments. In contrast, most of the less common species were more abundant in the smallest fragments. The abundance of pollinators (those found on inflorescences of both phases and dusted with pollen that was carried to flower stigmas), and the ratio of pollinators to other floral visitors, increased with fragment size in both sexual phases of the inflorescences but these effects were significantly stronger on male-phase inflorescences than on female-phase inflorescences. These results show that tropical forest fragmentation correlates with changes in the composition of flower visitors to a dominant palm, with a reduction in the abundance of pollinators, but that such changes co-vary with the sexual phase of the plants.

Although several damaged mangrove ecosystems have been restored worldwide, so far, it has not been established whether a restored mangrove system regains all the functional properties of preserved mangroves. This study measured nitrogen fixation as an indicator of whether disturbed mangroves that were reforested or naturally regenerated fully recovered from this disturbance at a functional level. Rates of nitrogen fixation were measured for one year in impaired, preserved, reforested, and naturally regenerated mangroves dominated by the black mangrove (Avicennia germinans). There was no significant difference in rates of nitrogen fixation among preserved and adjacent reforested and naturally regenerated mangroves, but a significant reduction occurred in an impaired mangrove. Nitrogen fixation was mainly controlled by pH, salinity, and temperature. The highest rates of nitrogen fixation occurred in summer at pH values less than 6.4, whereas the impaired mangrove had higher pH and salinity and had very low nitrogen fixation activity. These results suggest that nitrogen fixation can be used as an ecological indicator of the success of reforestation and as a sensitive measure of perturbations in mangroves.

For all its positive attributes, the recent expansion of ecotourism has resulted in greater influxes of people into natural areas, causing a range of impacts including behavioral disruptions among wildlife. How animals respond to conversation is poorly understood, but noise reduction may reduce the impact of ecotourists while simultaneously enhancing their experience with higher wildlife encounter rates. We tested the response of a rain forest bird community to noise by playing a recorded conversation while conducting point censuses in a terra firme forest in Tambopata, Peru. Fifty decibel conversation (approximately library speaking volume) caused declines of 35 percent in total detections and 33 percent in detected species richness. Birds reacted similarly to 60dB (approximately the volume of an excited child): average detections declined by 39 percent and detected species richness by 37 percent. Specifically, noise-induced detection declines were manifest both in decreased vocalizations (37% decline) and decreased physical sightings (44% decline). Lowered detection frequencies indicate behavioral shifts. As vocalization is involved in territory defense, breeding behavior, and predator detection, strong noise responsiveness indicates potential harm for birds. Insectivores were the most affected bird guild, raising conservation concerns, as insectivorous birds are sensitive to habitat modification. Birds reacted strongly to noise both near an established ecotourist lodge and in an intact reserve, indicating an absence of habituation. Thus, as a method for reducing ecotourism’s footprint on native fauna and improving tourist satisfaction with increased wildlife sightings, noise reduction seems promising, even for well-established ecotourist lodges.

The consequences of tropical forest fragmentation on herbivory are poorly understood. The limited evidence suggests that forest fragmentation can have positive, negative or neutral effects on herbivory. Inconsistencies may be partly explained by plant interspecific variation and differential responses related to plant life history. In this study we examined the effects of forest fragmentation and plant regeneration mode (shade-tolerant and light-demanding species) on sapling herbivory using a large sample of the community (97 species, representing 25% of the woody flora of the study site), and a subset of species shared by forest fragments and continuous forest. For the latter, we also analyzed the effects of species identity on variation in herbivory. Also, for the shared species we used two techniques to measure herbivory: standing herbivory (i.e. instantaneous, actual damage) and cumulative herbivory (i.e. damage, accumulated over time, on initially intact leaves). Insect herbivory was the predominant type of damage in the two forest types, and standing herbivory at both the community and the shared species level was significantly higher in continuous forest than in fragments. Considering shared species, both standing and cumulative herbivory were significantly higher in light-demanding than in shade-tolerant species. Cumulative herbivory also showed a significant interaction between forest fragmentation and plant regeneration mode, whereby a significant decline in herbivory in fragments was driven by reduced herbivory in shade-tolerant species, whereas for light-demanding species herbivory did not change significantly, due to contrasting species-specific responses. We conclude that tropical forest fragmentation reduces insect herbivory, but this depends on plant regeneration mode and species identity. These changes could have effects on plant regeneration and diversity in forest fragments via long-term demographic consequences.

Question: Vascular epiphytes and hemiepiphytes (E/HE) in neotropical forests account for a large fraction of plant richness, but little is known of how the interplay between phorophyte architectural characteristics and habitat perturbation affect communities of E/HE. Location: Sabal mexicana forests in a coastal area of Veracruz, Mexico. Methods: We compared communities of E/HE on phorophytes with different architectural characteristics – the palm S. mexicana and non-palm phorophytes – in three environments: conserved sites, perturbed sites and small regenerated forest fragments. We combined traditional (abundance, species richness, similarity and complementarity indices) and more recent (phylogenetic diversity) metrics to describe the communities of E/HE. Results: Overall, we recorded 924 E/HE individuals (nine families, 16 genera and 21 species). The abundance and species richness of E/HE was higher on palms than on non-palm phorophytes. Abundance-based complementarities between phorophytes and sites were high. We detected clear changes in community structure of E/HE with habitat perturbation, but there were no effects on the phylogenetic diversity of the E/HE community. Palm phorophytes hosted a more phylogenetically diverse community of E/HE than did non-palm phorophytes. Conclusions: Palm phorophytes are key elements supporting the conservation of resilient communities of E/HE in S. mexicana forest. Habitat fragmentation has a strong effect on the structure of the E/HE community in S. mexicana forests. Ferns are the group of epiphytes most severely affected by habitat perturbation, but we detected no significant effect on the phylogenetic diversity of the community.

Environmental assessment at the community level in highly diverse ecosystems is limited by taxonomic constraints and statistical methods requiring true replicates. Our objective was to show how diverse systems can be studied at the community level using higher taxa as biodiversity surrogates, and re-sampling methods to allow comparisons. To illustrate this we compared the abundance, richness, evenness and diversity of the litter fauna in a pine-oak forest in central Mexico among seasons, sites and collecting methods. We also assessed changes in the abundance of trophic guilds and evaluated the relationships between community parameters and litter attributes. With the direct search method we observed differences in the rate of taxa accumulation between sites. Bootstrap analysis showed that abundance varied significantly between seasons and sampling methods, but not between sites. In contrast, diversity and evenness were significantly higher at the managed than at the non-managed site. Tree regression models show that abundance varied mainly between seasons, whereas taxa richness was affected by litter attributes (composition and moisture content). The abundance of trophic guilds varied among methods and seasons, but overall we found that parasitoids, predators and detrivores decreased under management. Therefore, although our results suggest that management has positive effects on the richness and diversity of litter fauna, the analysis of trophic guilds revealed a contrasting story. Our results indicate that functional groups and re-sampling methods may be used as tools for describing community patterns in highly diverse systems. Also, the higher taxa surrogacy could be seen as a preliminary approach when it is not possible to identify the specimens at a low taxonomic level in a reasonable period of time and in a context of limited financial resources, but further studies are needed to test whether the results are specific to a system or whether they are general with regards to land management.

Made available in DSpace on 2018-12-11T16:57:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-10-01 Most tropical rainforests have been defaunated of large-bodied mammals and the cascading effects of such extirpations have been poorly studied, particularly on other animals. We used a natural experiment in the Brazilian Atlantic rainforest to investigate the ecological responses of rodents to the functional extinction of a dominant terrestrial mammal, the white-lipped peccary (Tayassu pecari). We detected a 45% increase in the abundance and a decrease in diversity of rodents in defaunated forests. Two of these species (Akodon montensis and Oligoryzomys nigripes) are important hosts of Hantavirus, a lethal virus for humans. Stable isotope ratios (δ13C and δ15N) derived from the hair of rodents and peccaries and their food resources indicate that at least two rodent species shifted to a diet more similar to peccaries in the defaunated forest. Because most tropical rainforests are facing dramatic extirpation of large mammals, we can expect changes in the composition and structure of small mammal communities with potential consequences for human health even in non-fragmented landscapes. Universidade Estadual Paulista (UNESP), Departamento de Ecologia, C.P. 199, Rio Claro Instituto de Ecología, A.C. Red de Biología Evolutiva, Carretera Antigua a Coatepec 351 CENA, Universidade de São Paulo, C.P. 96 Department of Ecology and Evolutionary Biology, University of California Santa Cruz School of Life Sciences, Peking University Santa Fe Institute Universidade Estadual Paulista (UNESP), Departamento de Ecologia, C.P. 199, Rio Claro

It has been suggested that tropical defaunation may unleash community-wide cascading effects, leading to reductions in plant diversity. However, experimental evidence establishing cause–effect relationships thereof is poor. Through a 5 year exclosure experiment, we tested the hypothesis that mammalian defaunation affects tree seedling/sapling community dynamics leading to reductions in understorey plant diversity. We established plot triplets ( n = 25) representing three defaunation contexts: terrestrial-mammal exclosure (TE), medium/large mammal exclosure (PE) and open access controls (C). Seedlings/saplings 30–100 cm tall were marked and identified within each of these plots and re-censused three times to record survival and recruitment. In the periods 2010–2011 and 2011–2013, survival was greater in PE than in C plots and recruitment was higher in TE plots than in C plots. Overall, seedling density increased by 61% in TE plots and 23% in PE plots, whereas it decreased by 5% in C plots. Common species highly consumed by mammals (e.g. Brosimum alicastrum and Ampelocera hottlei ) increased in their abundance in TE plots. Rarefaction curves showed that species diversity decreased in TE plots from 2008 to 2013, whereas it remained similar for C plots. Given the prevalence of tropical defaunation, we posit this is an anthropogenic effect threatening the maintenance of tropical forest diversity.

En la primera parte de este estudio se investigaron los patrones estructurales de la comunidad de mesofauna en un bosque mesófilo de montaña encontrando que la hojarasca y el suelo como tal albergan comunidades estructuralmente diferentes. La hojarasca parece ser un hábitat complejo, heterogéneo, mientras que el suelo parece ser homogéneo. Las principales diferencias entre los dos hábitats están dadas por la abundancia de ácaros y colémbolos y se discuten sus patrones de distribución en relación con aquellos factores que pudiesen estar determinando la actividad de la micobiota en el suelo ya que la fungivoría es un hábito ampliamente distribuido entre ácaros y colémbolos. En la segunda parte de este estudio se realizaron experimentos de microcosmos en los que se observó que la actividad trófica de una especie de ácaro (Oppidae) afecta la producción de esporas de cuatro especies de hongos lo que sugiere un efecto sobre su capacidad competitiva.