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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.

Habitat specialists are particularly vulnerable to extinction when habitat conditions are altered. Information on the habitat use of such species is thus important because it provides insight into factors that influence distribution and abundance, which is crucial for conservation. Here, we aimed to identify factors that influence the patterns of presence and abundance of the Endangered volcano rabbit Romerolagus diazi, a rare leporid with a patchy distribution. Through exhaustive sampling of its range in the Sierra Chichinautzin and Sierra Nevada volcanic fields, Mexico, and using generalized linear models, we found that the probability of patch occupancy was higher where bunchgrass cover exceeded 75%, rock cover exceeded 5%, no cattle grazing was observed and human settlements were at least 7 km away. Patches with greater relative abundance were those with similar characteristics, but located at elevations > 3,600 m, and with rock cover < 15%. Cattle grazing was identified as a major threat to local populations of the volcano rabbit, particularly in the Sierra Chichinautzin. Because of the significance of bunchgrasses for this species, the protection of the mountain grasslands is required in both volcanic fields.

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.

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.

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.

1. Crown displacement in trees is an adaptive response driven by neighbours that optimizes space use and reduces competition. But it can also be the result of wind force. Although morphological responses to neighbours have been well studied, the interplay between neighbours and wind in driving crown shape, and the implications for plant interactions remain poorly understood. However, it is crucial to predict such changes in vegetation structure and function under the scope of global change. We test the hypothesis that aboveground interactions are reduced with increasing soil stress and that wind becomes the main driver of crown shape in mangrove forests.\ud 2. We investigated the effect of neighbours and wind intensity and direction on crown displacement of mangrove canopy and below canopy trees along a salinity gradient, and assessed crown asymmetry for three mangrove tree species, as well as the contribution of crown displacement on reducing crown‐projected area overlap and thus neighbourhood competition.\ud 3. Results show that crown displacement of canopy trees is strongly influenced by winds at all salinities. At low salinities, competition for space accounted for 48% of crown displacement away from neighbours, compared to 49% found for the synthetized effects of wind and neighbours. While trees below the canopy displace their crowns away from their neighbours, no response to wind could be detected. This can be due to the wind protection conferred by a dense canopy stand related to bigger crowns that effectively reduce wind drag. At higher salinities, there was a reduction in canopy overlap due to crown displacement, which suggests reduced aboveground plant interactions with increasing soil stress.\ud 4. While neighbourhood avoidance is a fundamental strategy for optimal light foraging, this study shows that wind strength and directionality are main drivers of crown shape with increasing stress and highlights their potential influence in plant interactions and forest structure, pointing to an increased susceptibility of trees to disturbances that should be further studied.

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.

Leaf traits of tropical tree species are known to operate as intrinsic determinants of insect herbivory. However, we know little about how habitat fragmentation affects these traits and what, if any, are the consequences of this process on herbivory. We tested the effects of forest fragmentation on the leaf traits of sapling of four light-demanding species: Acalypha diversifolia, Hampea nutricia, Myriocarpa longipes, Siparuna thecaphora, and two shade-tolerant species: Pseudolmedia glabrata and Garcinia intermedia, in Los Tuxtlas, Mexico. We also conducted an acceptability assay with a generalist herbivore Spodoptera frugiperda. Plant traits did not change with forest fragmentation, but did with plant regeneration mode and species identity. Light-demanding species had significantly higher water content, nitrogen concentration and specific leaf area than shade-tolerant species. The latter had significantly higher leaf strength, carbon concentration and carbon:nitrogen ratio. Acceptability was affected by fragmentation but only in P. glabrata; plant tissue from forest fragments was consumed 2.6 times more than that from continuous forest. We conclude that forest fragmentation did not affect leaf traits in this site.

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.

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.

The effectiveness of seed dispersal by vertebrates has been analysed by examining both quantitative and qualitative components (Jordano & Schupp 2000, Schupp et al. 2010). While the quantitative component is relatively easily assessed in the field (e.g. visitation rate, number of fruits eaten per visit), the qualitative component (e.g. fate of dispersed seeds, seed treatment in the digestive system of the disperser) is rarely studied under natural conditions, because it is difficult to measure the effects on seeds once ingested by the dispersers (Cortes et al. 2009).

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.

Heterogeneous distribution of resources in most plant populations results in a mosaic of plant physiological responses tending to maximize plant fitness. This includes plant responses to trophic interactions such as herbivory and mycorrhizal symbiosis which are concurrent in most plants. We explored fitness costs of 50% manual defoliation and mycorrhizal inoculation in Datura stramonium at different light availability and soil fertility environments in a greenhouse experiment. Overall, we showed that non-inoculated and mycorrhiza-inoculated plants did not suffer from 50% manual defoliation in all the tested combinations of light availability and soil fertility treatments, while soil nutrients and light availability predominately affected plant responses to the mycorrhizal inoculation. Fifty percent defoliation had a direct negative effect on reproductive traits whereas mycorrhiza-inoculated plants produced larger flowers than non-inoculated plants when light was not a limiting factor. Although D. stramonium is a facultative selfing species, other investigations had shown clear advantages of cross-pollination in this species; therefore, the effects of mycorrhizal inoculation on flower size observed in this study open new lines of inquiry for our understanding of plant responses to trophic interactions. Also in this study, we detected shifts in the limiting resources affecting plant responses to trophic interactions.

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.

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

Made available in DSpace on 2018-12-11T17:25:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-05-04 Defaunation can trigger cascading events in natural communities and may have strong consequences for plant recruitment in tropical forests. Several species of large seed predators, such as deer and peccaries, are facing dramatic population collapse in tropical forests yet we do not have information about the consequences of these extinctions for seed predation. Using remote camera traps we tested if defaunated forests have a lower seed predation rate of a keystone palm (. Euterpe edulis) than pristine areas. Contrary to our expectation, we found that seed predation rates were 2.5 higher in defaunated forests and small rodents were responsible for most of the seeds eaten. Our results found that defaunation leads to changes in the seed predator communities with potential consequences for plant-animal interactions. Departamento de Ecologia, Universidade Estadual Paulista (UNESP), C.P. 199 Instituto de Ecología, A.C. Departamento de Biología Evolutiva, Apartado Postal 63 Departamento de Ecologia, Universidade Estadual Paulista (UNESP), C.P. 199

The ciid beetles Octotemnus glabriculus and Cis boleti exploit different developmental stages of fruit bodies of their preferred host fungus Coriolus versicolor. Larvae of the smaller beetle, O. glabriculus, mainly use young, expanding, fruit bodies; adults of O. glabriculus are predominantly found in young fruit bodies. By contrast, adults and larvae of the larger beetle, C. boleti, are prevalent in fully developed fruit bodies of C. versicolor. Because fruit bodies of most genets emerge during spring and early summer and mature by autumn, O. glabriculus and C. boleti breed in separated seasons. Adults and larvae of O. glabriculus are abundant in spring and early summer. By contrast, the number of adults and larvae of C. boleti increases gradually from late spring to summer and peaks in autumn. We conducted a field experiment that suggests that the phenological dynamics of C. versicolor fruit bodies drive the separation of breeding seasons between O. glabriculus and C. boleti. Additionally, laboratory experiments revealed that O. glabriculus and C. boleti have differential behavioural responses to odour compounds from young and mature fruit bodies of C. versicolor. We conclude that age-related changes in the chemical composition of fruit bodies may allow O. glabriculus and C. boleti to discriminate among C. versicolor, thus providing a mechanism for the partitioning of the resource.

Most ciids (Ciidae) are strict fungivores specialized on fruit bodies of wood-rotting fungi. The Ciidae includes both specialist and generalist species. Recent evidence suggests that ciids locate and discriminate their potential hosts based mainly on fungal odours. In this study, we investigated the field distribution of ciids in a local woodland near Bath, U.K. We also evaluated experimentally the behavioural responses of ciids to host and non-host fungi in an olfactometer, and explored potential differences in putative aroma compounds in host fungi. Our field data showed that Octotemnus glabriculus, Cis boleti and Cis nitidus have preference for one host species, whereas C. bilamellatus has no preference. The experimental evidence was in accordance with the field observations. The specialists O. glabriculus, C. boleti and C. nitidus were specifically attracted to odour compounds of their preferred host fungi: Coriolus versicolor for the first two beetles and Ganoderma adspersum for the latter one. By contrast, the generalist C. bilamellatus was attracted to odours from C. versicolor, G. adspersum and Piptoporus betulinus. The evidence from this and other published studies suggest that ciids depend mainly on fruit body odours for location and discrimination of their host fungi. In accordance with this, we observed diffierential behavioural responses of ciids to aroma compounds of host and non-host species.

The emphasis of antagonistic fungus–consumer interactions to date has been on temperate taxa and predominantly zoocentric, neglecting the effects on the fungal component. These interactions are expected to be especially complex and diverse in the tropics, where both components display their greatest diversity. Variability in fungivory (apparent biomass consumed) of understorey basidiomycetes in a tropical cloud forest was investigated to test whether this could be explained (at the proximate level) by apparency-related characteristics of the aboveground structures (colour of pileus, stipe and hymenium; size and aggregation), as has been suggested for plant–herbivore relationships. Considerable interspecific variation in fungivory was detected (range 0–50%). Cluster analysis showed that neighbouring clusters had dissimilar levels of fungivory. Such clusters were similar in colour attributes of aboveground structures, but differed in aggregation size and apparent biomass. A quantitative analysis also showed that colour attributes were not strongly associated with the observed variation of consumption levels, whereas apparent biomass and aggregation size did correlate with the observed variation in fungivory. Furthermore, specific identity correlated with fungivory. It was concluded that coloration patterns may not be important for fungivory, whereas genet size and species identity (probably via characteristics unrelated to apparency, such as mycotoxins and nutritional value) seemed to be critical factors.

Arbuscular mycorrhizal colonization in strangler figs, spore richness, and abundance of arbuscular mycor- rhizal fungi were quantified in epiphytic and ground-rooted trees in a Sabal palmetto woodland that had marked heterogeneity in rooting environments for hemiepiphytic plants. An inoculation experiment was performed to assess whether low spore density could limit mycorrhizal coloni- zation. There was no significant difference in mycorrhizal colonization among Ficus species, but epiphytic plants in nutrient-rich rooting environments had less mycorrhizal colonization than ground-rooted plants in low-nutrient soils. However, richness and abundance of spores was low, and to some extent, this limited the mycorrhizal colonization of strangler figs. Nevertheless, our results suggest intraindividual adjusting levels of root colonization in strangler figs in accordance with mineral availability. Such responses could maximize the cost-benefit balance of arbuscular mycorrhizal interactions throughout the devel- opment of strangler figs from epiphytic young plants to ground-rooted trees.

The hypothesis that plant species are more responsive to mycorrhiza in late than in early successional stages was assessed in grasses from a successional process occurring in two-phase mosaics from the Mexican Chihuahuan Desert. We estimated the density of spores of arbuscular mycorrhizal (AM) fungi and the AM colonization of pioneer and late-successional grasses in the field. In growth chamber experiments, we tested the effect of the native AM fungal community on grasses growing in soils from different successional stages. Spore density was higher in late than in early successional stages. Late-successional species were more responsive to AM (positive AM responsiveness) whereas pioneer species were nondependent on mycorrhiza or if associated to AM fungi, the interaction showed a negative AM responsiveness for the seedling stage. Our findings showed that late successional species fitted the proposed models of mycorrhizal performance, but the two pioneer species differed in their AM condition and responsiveness. This further supports the idea that AM interactions are more complex along the successional processes than the predictions of the more widely cited hypotheses.