Animal Dispersal Research Articles

Broken bridges: The isolation of Kilimanjaro's ecosystem.

Biodiversity studies of global change mainly focus on direct impacts such as losses in species numbers or ecosystem functions. In this study, we focus on the long-term effects of recent land-cover conversion and subsequent ecological isolation of Kilimanjaro on biodiversity in a paleobiogeographical context, linking our findings with the long-standing question whether colonization of African mountains mainly depended on long-distance dispersal, or whether gradual migration has been possible through habitat bridges under colder climates. For this, we used Orthoptera as bioindicators, whose patterns of endemism and habitat demands we studied on about 500 vegetation plots on Kilimanjaro and Mt. Meru (Tanzania) since 1996. Land-cover changes in the same area were revealed using a supervised classification of Landsat images from 1976 to 2000. In 1976, there was a corridor of submontane forest vegetation linking Kilimanjaro with Mt. Meru, replaced by human settlements and agriculture after 2000. Until recently, this submontane forest bridge facilitated the dispersal of forest animals, illustrated by the large number of endemic submontane forest Orthoptera shared by both mountains. Furthermore, the occurrence of common montane endemics suggests the existence of a former forest corridor with montane vegetation during much earlier times under climatic conditions 2-7°C cooler and 400-1,700mm wetter than today. Based on the endemicity patterns of forest Orthoptera, negative consequences are predicted due to the effects of isolation, in particular for larger forest animals. Kilimanjaro is becoming an increasingly isolated ecosystem with far reaching consequences for diversity and endemism. Forest bridges between East African mountains acted as important migratory corridors and are not only a prehistoric phenomenon during periods with other climatic conditions but also disappeared in some places recently due to increasing and direct anthropogenic impact.

Radio-Tracking Suggests High Dispersal Ability of the Great Capricorn Beetle (Cerambyx cerdo)

Dispersal ability is among the key factors affecting the survival of species in today’s fragmented landscapes. One of the most straightforward methods to provide direct measures of animal dispersal is telemetry. Despite its merits, this method has rarely been used for saproxylic beetles. In this study, we examined dispersal ability of the Great Capricorn beetle Cerambyx cerdo (Coleoptera: Cerambycidae), an endangered veteran oak specialist. Using a radio-tracking approach, we tracked 26 individuals (15 males and 11 females) equipped with transmitters for 4 to 17 days (median 14). We observed no disturbance of movements or flight problems due to the transmitter. The daily probability of movement by an individual was 64% and the longest displacement in one day was 1498 m for males and 1080 m for females. For 15% of all individuals, the tracking distance covered was >2200 m. Our results indicate that C. cerdo individuals often move among trees over an area of several kilometres. Such findings contrast with previous results based on a mark-recapture study. The relatively high mobility of the species should be reflected in strategies aiming at its conservation.

Striking Iron: The Art of African Blacksmiths

Striking Iron: The Art of African Blacksmiths

How People Domesticated Amazonian Forests

For millennia, Amazonian peoples have managed forest resources, modifying the natural environment in subtle and persistent ways. Legacies of past human occupation are striking near archaeological sites, yet we still lack a clear picture of how human management practices resulted in the domestication of Amazonian forests. The general view is that domesticated forests are recognizable by the presence of forest patches dominated by one or a few useful species favored by long-term human activities. Here, we used three complementary approaches to understand the long-term domestication of Amazonian forests. First, we compiled information from the literature about how indigenous and traditional Amazonian peoples manage forest resources to promote useful plant species that are mainly used as food resources. Then, we developed an interdisciplinary conceptual model of how interactions between these management practices across space and time may form domesticated forests. Finally, we collected field data from 30 contemporary villages located on and near archaeological sites, along four major Amazonian rivers, to compare with the management practices synthesized in our conceptual model. We identified eight distinct categories of management practices that contribute to form forest patches of useful plants: (1) removal of non-useful plants, (2) protection of useful plants, (3) attraction of non-human animal dispersers, (4) transportation of useful plants, (5) selection of phenotypes, (6) fire management, (7) planting of useful plants, and (8) soil improvement. Our conceptual model, when ethnographically projected into the past, reveals how the interaction of these multiple management practices interferes with natural ecological processes, resulting in the domestication of Amazonian forest patches dominated by useful species. Our model suggests that management practices became more frequent as human population increased during the Holocene. In the field, we found that useful perennial plants occur in multi-species patches around archaeological sites, and that the dominant species are still managed by local people, suggesting long-term persistence of ancient cultural practices. The management practices we identified have transformed plant species abundance and floristic composition through the creation of diverse forest patches rich in edible perennial plants that enhanced food production and food security in Amazonia.

Basic model of purposeful kinesis

The notions of taxis and kinesis are introduced and used to describe two types of behaviour of an organism in non-uniform conditions: (i) Taxis means the guided movement to more favourable conditions; (ii) Kinesis is the non-directional change in space motion in response to the change of conditions. Migration and dispersal of animals has evolved under control of natural selection. In a simple formalisation, the strategy of dispersal should increase Darwinian fitness. We introduce new models of purposeful kinesis with diffusion coefficient dependent on fitness. The local and instant evaluation of Darwinian fitness is used, the reproduction coefficient. New models include one additional parameter, intensity of kinesis, and may be considered as the minimal models of purposeful kinesis. The properties of models are explored by a series of numerical experiments. It is demonstrated how kinesis could be beneficial for assimilation of patches of food or of periodic fluctuations. Kinesis based on local and instant estimations of fitness is not always beneficial: for species with the Allee effect it can delay invasion and spreading. It is proven that kinesis cannot modify stability of homogeneous positive steady states.

CLIMATE CHANGE AND ITS EFFECTS ON HUMAN HEALTH

Climate change will also affect human health. The frequency of infectious diseases like diarrhoea, dysentery, cholera and typhoid fever will increase. According to the report of the World Health Organisation, there will be an increase in respiratory and heart related diseases due to climate change. Human health is impacted by climate change both directly and indirectly. Direct harm, disease, and even death can be brought on by extreme heat waves, increasing sea levels, changes in precipitation that lead to flooding and droughts, and powerful hurricanes. Via environmental changes, the consequences of climate change can also have an indirect impact on health. For instance, respiratory and cardiovascular problems may be negatively impacted by worsening air pollution levels. Temperature and precipitation variations can affect the survival, dispersal, and behaviour of insects and other animals, which can modify the transmission of infectious diseases. Changes in precipitation, storm surge, and sea temperature may cause an increase in illnesses associated with drinking water. In addition to affecting food safety, climate change exposes people to tainted foods that can cause foodborne illnesses.

Облік мисливської фауни у форматі статзвітності «2-тп – мисливство»: особливості, переваги, недоліки

Users of hunting grounds keep a primary track of the numbers and hunting of game animals and birds. The procedure for keeping records of game animals and the volumes of hunting are established by the Ministry of Ecology and Natural Resources of Ukraine in agreement with the State Statistics Committee of Ukraine. In the hunting sector, the reporting form is "Game management" (No. 2-tp hunting). The report consists of four sections: the area of hunting grounds and the number of personnel; costs of running and income from game management; animal numbers, dispersal, and hunting of game animals; captive breeding of game animals. The annual inventory of game animals and birds provides long-term and systematic monitoring of populations, allows to assess the state of populations of the main game species, to analyse environmental factors that affect the abundance of game animals, to predict the development of faunistic situation in hunting grounds, to plan biotechnical activities and to organise sustainable use of game fauna. In order to obtain objective primary materials on the abundance of game animals and birds, there is a need to improve the counting process and census methods, to improve the skills of observers (spotters), and to introduce resource-saving methods for estimations of game fauna resources.

CONTINENTAL CONNECTIONS AND INSULAR DISTRIBUTIONS: DEER BONE ARTIFACTS OF THE PRECOLUMBIAN WEST INDIES—A REVIEW AND SYNTHESIS WITH NEW RECORDS

The remains of non-native deer (Cervidae) have been sparsely recorded in Amerindian archaeological sites of the West Indies, but evidence indicates the presence of at least two genera, white-tailed deer (Odocoileus) and brocket deer (Mazama), during the precolumbian era known as the Ceramic Age (ca. 500 BC–AD 1500). Due to underreporting of finds and lack of regional integration of existing records, however, the West Indian distribution of cervid remains and their cultural importance are not well understood. Here, I synthesize records for unmodified and modified deer bone from 29 archaeological sites on seven islands in the precolumbian island Caribbean with descriptions for four new records of deer bone artifacts from Carriacou and Grenada. I discuss taxonomic attribution issues, evidence for manufacturing techniques, and the utilitarian and symbolic significance of deer bone artifacts. Particular attention is given to proportions of worked and unworked bone, element diversity, and skeletal part representation as a means to distinguish the introduction of living deer from the introduction of carcass products. The evidence presented here is consistent with island Amerindians importing cervid bone as finished artifacts or raw material for tool and ornament manufacture rather than live animals. This study enhances our understanding of the ways in which Amerindians were engaged in exchange networks based on the movement of exotic goods between the West Indies and continent. More broadly, it contributes to conceptual methods for distinguishing the transfer of body parts from the translocation of live animals in studies of exotic animal dispersal by humans.

Waves of seed propagation induced by delayed animal dispersion

We study a model of seed dispersal that considers the inclusion of an animal disperser moving diffusively, feeding on fruits and transporting the seeds, which are later deposited and capable of germination. The dynamics depends on several population parameters of growth, decay, harvesting, transport, digestion and germination. In particular, the deposition of transported seeds at places away from their collection sites produces a delay in the dynamics, whose effects are the focus of this work. Analytical and numerical solutions of different simplified scenarios show the existence of travelling waves. The effect of zoochory is apparent in the increase of the velocity of these waves. The results support the hypothesis of the relevance of animal mediated seed dispersion when trying to understand the origin of the high rates of vegetable invasion observed in real systems.

Planting accelerates restoration of tropical forest but assembly mechanisms appear insensitive to initial composition

Abstract Central to the success of restoration is how applied activities influence community assembly mechanisms. Phylogenetic and trait‐based approaches to community ecology are increasingly being used to test for non‐random community assembly and are now being applied to assessments of habitat restoration. A critical question for the restoration of tropical forests is how plantings influence the recruitment of new species, and specifically the phylogenetic and functional diversity of restored habitats. We examined 8 years (2006–2014) of tropical‐forest recruitment in two restoration planting compositions (12 animal‐dispersed and 12 wind‐dispersed tree species), with a control (no planting) in 24 plots in Los Tuxtlas, Mexico. Specifically, we assessed the influence of plantings on newly arriving individuals’ phylogenetic, functional, taxonomic diversity, abundance and the change of these measures during early succession. The recruiting individuals’ phylogenetic, functional, taxonomic diversity and abundance increased through succession. Both animal‐dispersed planting and wind‐dispersed planting appeared to accelerate forest succession more than controls (natural succession), and diversity in the animal‐dispersed plantings was marginally higher after 8 years. We did not find any difference in recruiting individuals’ phylogenetic and functional dispersion (measured as standardized effect sizes) in any given year, or when measured as turnover between successive pairs of years, measuring planting composition and control plots. Recruiting individuals were phylogenetically clustered during early forest restoration regardless of treatment. At the same time, the recruits transitioned from appearing randomly constructed to clustering according to functional traits, which suggests an increase in recruits’ functional similarity during early succession. Synthesis and applications. Both the animal and wind‐dispersed plantings accelerated the increase of recruiting individuals’ phylogenetic, functional, taxonomic diversity and abundance during early succession. However, planting treatment did not appear to alter community assembly mechanisms of recruiting individuals. Our findings support restoration planting by showing that planting trees with animal dispersal syndrome could accelerate forest restoration more than unassisted forest regeneration. Furthermore, communities appeared to be phylogenetically and functionally clustered during early succession regardless of initial planted composition. Thus, while overall diversity increased with planting, if a restoration goal is to maximize phylogenetic or functional dispersion, the planting composition tested did not provide means to achieve this goal, at least during early succession.

Passive restoration following ungulate removal in a highly disturbed tropical wet forest devoid of native seed dispersers

AbstractOverabundant ungulate populations can alter forests. Concurrently, global declines of seed dispersers may threaten native forest structure and function. On an island largely devoid of native vertebrate seed dispersers, we monitored forest succession for 7 years following ungulate exclusion from a 5‐ha area and adjacent plots with ungulates still present. We observed succession from open scrub to forest and understory cover by non‐native plants declined. Two trees, native Hibiscus tiliaceus and non‐native Leucaena leucocephala, accounted for most forest regeneration, with the latter dominant. Neither species is dependent on animal dispersers nor was there strong evidence that plants dependent on dispersers migrated into the 5‐ha study area. Passive restoration following ungulate removal may facilitate restoration, but did not show promise for fully restoring native forest on Guam. Restoration of native forest plants in bird depopulated areas will likely require active outplanting of native seedlings, control of factors resulting in bird loss, and reintroduction of seed dispersers.

Colonization dynamics of a clonal pioneer plant on a glacier foreland inferred from spatially explicit and size-structured matrix models

The regional distribution of a plant species is a result of the dynamics of extinctions and colonizations in suitable habitats, especially in strongly fragmented landscapes. Here, we studied the role of spatial dynamics of the long-lived, clonal pioneer plant Geum reptans occurring on glacier forelands in the European Alps. We used demographic data from several years and sites in the Swiss Alps in combination with dispersal data to parametrize a matrix model for G. reptans to simulate extinctions, colonizations and spatial spread of established populations on glacial forelands. We used different scenarios with varying germination rates, wind and animal dispersal capabilities, and modes of spatial spread (seed-only vs clonal spread), resulting in population growth rates (λ) ranging from 1.04 to 1.20. Our results suggest that due to the low germination rate (~1%) and the very limited wind dispersal distances (99.8% of seeds are dispersed < 5 m), G. reptans has a low probability of establishing new populations and a very low spatial spread by seed dispersal alone. In contrast to the low rate of establishment, the persistence of established populations is high and even populations of only a few individuals have an extinction probability of less than 25% within 100 years. This high persistency is partly due to clonal reproduction via aboveground stolons. Clonal reproduction increases the population size and contributes considerably to the spatial spread of established populations. Our simulation results together with the known pattern of molecular diversity of G. reptans indicate that the occurrence of populations of this species in the Alps is unlikely to be a result of recent colonizations by long-distance dispersal, but rather a result of post-glacial colonizations by large migrating populations that were fragmented when glaciers retreated. Additionally, our simulations suggest that the currently observed high rates of glacial retreat might be too fast for pioneer plants, such as G. reptans, to keep up with the retreating ice and therefore might threaten existing populations.

Closing the gaps for animal seed dispersal: Separating the effects of habitat loss on dispersal distances and seed aggregation.

Habitat loss can alter animal movements and disrupt animal seed dispersal mutualisms; however, its effects on spatial patterns of seed dispersal are not well understood. To explore the effects of habitat loss on seed dispersal distances and seed dispersion (aggregation), we created a spatially explicit, individual‐based model of an animal dispersing seeds (SEADS—Spatially Explicit Animal Dispersal of Seeds) in a theoretical landscape of 0%–90% habitat loss based on three animal traits: movement distance, gut retention time, and time between movements. Our model design had three objectives: to determine the effects of (1) animal traits and (2) habitat loss on seed dispersal distances and dispersion and (3) determine how animal traits could mitigate the negative effects of habitat loss on these variables. SEADS results revealed a complex interaction involving all animal traits and habitat loss on dispersal distances and dispersion, driven by a novel underlying mechanism of fragment entrapment. Unexpectedly, intermediate habitat loss could increase dispersal distances and dispersion relative to low and high habitat loss for some combinations of animal traits. At intermediate habitat loss, movement between patches was common, and increased dispersal distances and dispersion compared to continuous habitats because animals did not stop in spaces between fragments. However, movement between patches was reduced at higher habitat loss as animals became trapped in fragments, often near the parent plant, and dispersed seeds in aggregated patterns. As movement distance increased, low time between movements and high gut retention time combinations permitted more movement to adjacent patches than other combinations of animal traits. Because habitat loss affects movement in a nonlinear fashion under some conditions, future empirical tests would benefit from comparisons across landscapes with more than two levels of fragmentation.

Predicting island biosecurity risk from introduced fauna using Bayesian Belief Networks

Around the globe, islands are the last refuge for many threatened and endemic species. Islands are frequently also important sites for recreation, cultural activities, and industrial development, all of which facilitate the establishment of invasive species. Surveillance is employed on islands to detect the establishment of invasive species after their arrival, leading to decisions about follow-up actions. Unless surveillance is prioritised according to risk of establishment of invasives, it may be infeasible to implement efficiently over large tracts of publicly accessible land, especially in data-deficient areas. The key biosecurity problem for many regions is one of prioritizing sites for surveillance activities and identifying invasive species most likely to disperse to, and establish, and proliferate on those sites. We created a series of Bayesian Belief Networks (BBNs), linked by Java computing code and the freely available GeNIe application to automate the creation and computation of species- and site-specific biosecurity BBNs. The BBNs require data on island attributes, recreational or industrial visitor load, infrastructure, habitat availability, and animal behaviour and dispersal via swimming, flying, human movement, land bridges, or flood plumes. We used this biosecurity BBN to estimate the risk of 11 invasive faunal species arriving and establishing on 600 islands along the Pilbara coastline, Western Australia. Sensitivity analyses were conducted to identify nodes within the BBNs that required refined data inputs. Propagule pressure was the node with the greatest influence over the number of arrivals. Other nodes such as the number of visitors to islands and swimming capabilities of invasive animals greatly influenced the model results. Across the 11 species studied, our models predicted one arrival per 300 visitors. The biosecurity BBN can be used to identify the islands at highest risk from establishment of invasive species within any archipelago/s, and the invasive species most likely to establish on each island.

Numerical solutions of one-dimensional parabolic convection-diffusion problems arising in biology by the Laguerre collocation method

In this work, we present a numerical scheme for the approximate solutions of the one-dimensional parabolic convection-diffusion model problems. Diffusion models form a reasonable basis for studying insect and animal dispersal and invasion, which arise from the question of persistence of endangered species, biodiversity, disease dynamics, multi-species competition so on. Convection diffusion problem is also a form of heat and mass transfer in biological models. The presented method is based on the Laguerre collocation method used for these problems of differential equations. In fact, the approximate solution of the problem in the truncated Laguerre series form is obtained by this method. By substituting truncated Laguerre series solution into the problem and by using the matrix operations and the collocation points, the suggested scheme reduces the problem to a linear algebraic equation system. By solving this equation system, the unknown Laguerre coefficients can be computed. The accuracy and the efficiency of the method is showed by numerical examples and the comparisons by the other methods.

Why non-native grasses pose a critical emerging threat to biodiversity conservation, habitat connectivity and agricultural production in multifunctional rural landscapes

ContextLandscape-scale conservation planning is key to the protection of biodiversity globally. Central to this approach is the development of multifunctional rural landscapes (MRLs) that maintain the viability of natural ecosystems and promote animal and plant dispersal alongside agricultural land uses.ObjectivesWe investigate evidence that non-native grasses (NNGs) in rangelands and other low-intensity agricultural systems pose a critical threat to landscape conservation initiatives in MRLs both in Australia and globally.MethodsWe first establish a simple socio-ecological model that classifies different rural landscape elements within typical MRLs based on their joint conservation and agro-economic value. We then quantify the impacts of eight Australian NNGs (Andropogon gayanus, Cenchrus ciliaris, Eragrostis curvula, Hyparrhenia hirta, Nassella neesiana, Nassella trichotoma, Phalaris aquatica and Urochloa mutica) on different landscape elements and then classify and describe the socio-ecological transformations that result at the MRL scale.ResultsOur data indicate that two broad classes of NNGs exist. The first reduces both conservation and agro-economic value (‘co-degrading’ species) of invaded landscapes, while the second improves agro-economic value at the expense of conservation value (‘trade-off’ species). Crucially, however, both classes cause hardening of the landscape matrix, agricultural intensification, reduced habitat connectivity, and the loss of multi-value land use types that are vital for landscape conservation.ConclusionsNNGs drive socio-ecological transformations that pose a growing threat to landscape-scale connectivity and conservation initiatives in Australia and globally. There is an urgent need for further research into the impacts of NNGs on habitat connectivity and biodiversity within multifunctional landscapes, and the socio-ecological goals that can be achieved when landscape transformation and degradation by these species is unavoidable.

Atlantic frugivory: a plant-frugivore interaction data set for the Atlantic Forest.

The data set provided here includes 8,320 frugivory interactions (records of pairwise interactions between plant and frugivore species) reported for the Atlantic Forest. The data set includes interactions between 331 vertebrate species (232 birds, 90 mammals, 5 fishes, 1 amphibian, and 3 reptiles) and 788 plant species. We also present information on traits directly related to the frugivory process (endozoochory), such as the size of fruits and seeds and the body mass and gape size of frugivores. Data were extracted from 166 published and unpublished sources spanning from 1961 to 2016. While this is probably the most comprehensive data set available for a tropical ecosystem, it is arguably taxonomically and geographically biased. The plant families better represented are Melastomataceae, Myrtaceae, Moraceae, Urticaceae, and Solanaceae. Myrsine coriacea, Alchornea glandulosa, Cecropia pachystachya, and Trema micrantha are the plant species with the most animal dispersers (83, 76, 76, and 74 species, respectively). Among the animal taxa, the highest number of interactions is reported for birds (3,883) followed by mammals (1,315). The woolly spider monkey or muriqui, Brachyteles arachnoides, and Rufous-bellied Thrush, Turdus rufiventris, are the frugivores with the most diverse fruit diets (137 and 121 plants species, respectively). The most important general patterns that we note are that larger seeded plant species (>12 mm) are mainly eaten by terrestrial mammals (rodents, ungulates, primates, and carnivores) and that birds are the main consumers of fruits with a high concentration of lipids. Our data set is geographically biased, with most interactions recorded for the southeast Atlantic Forest.

Variation in home range size of red foxes Vulpes vulpes along a gradient of productivity and human landscape alteration.

Home range size is a fundamental concept for understanding animal dispersion and ecological needs, and it is one of the most commonly reported ecological attributes of free-ranging mammals. Previous studies indicate that red foxes Vulpes vulpes display great variability in home range size. Yet, there has been little consensus regarding the reasons why home range sizes of red foxes vary so extensively. In this study, we examine possible causes of variation in red fox home range sizes using data from 52 GPS collared red foxes from four study areas representing a gradient of landscape productivity and human landscape alteration in Norway and Sweden. Using 90% Local Convex Hull home range estimates, we examined how red fox home range size varied in relation to latitude, elevation, vegetation zone, proportion of agricultural land and human settlement within a home range, and sex and age. We found considerable variation in red fox home range sizes, ranging between 0.95 km2 to 44 km2 (LoCoH 90%) and 2.4 km2 to 358 km2 (MCP 100%). Elevation, proportion of agricultural land and sex accounted for 50% of the variation in home range size found amongst foxes, with elevation having the strongest effect. Red foxes residing in more productive landscapes (those in more southern vegetation zones), had home ranges approximately four times smaller than the home ranges of foxes in the northern boreal vegetation zone. Our results indicate that home range size was influenced by a productivity gradient at both the landscape (latitude) and the local (elevation) scale. The influence of the proportion of agriculture land on home range size of foxes illustrates how human landscape alteration can affect the space use and distribution of red foxes. Further, the variation in home range size found in this study demonstrates the plasticity of red foxes to respond to changing human landscape alteration as well as changes in landscape productivity, which may be contributing to red fox population increases and northern range expansions.

Not All Plant Taxa Display Typical Latitude-Propagule Size Gradients: A Case Study In Arctostaphylos L. (Ericaceae)

Proposed causes of the latitudinal-propagule size gradient invoke differences among biome structures or seed dispersal syndromes. Latitudinal seed-size gradients so far have been predominantly investigated using entire floras, prompting the question of whether such trends exist at smaller scales. Here we consider effects of latitude and elevation on fruit size between and within species in Arctostaphylos L. (Ericaceae), a zoochorous, primarily Californian chaparral shrub genus. We measured fruit size, strongly correlated with seed size in Arctostaphylos, in three species of this genus from multiple localities in the Sierra Nevada foothills, and conducted a character analysis of fruit size across the genus using the standard California flora plant manual (Baldwin et al. 2012). Across the genus we found a weak negative correlation between fruit size and latitude (0.0026 mm diameter/km) and a weak positive correlation between fruit size and elevation (1.3 mm diameter/km). AIC indicates that these trends are not explained by autocorrelation between fruit size and other variables such as maximum plant size. By contrast, intraspecific field data revealed a positive relationship between fruit size and both elevation and latitude. Propagule size gradients within Arctostaphylos oppose those reported for angiosperms globally. This contrast may result from uniformity of fruit structure and animal dispersal, disturbance ecology of chaparral, or local precipitation gradients characteristic of Mediterranean-type climates. Studies of propagule size gradients within taxa can uncover ecological mechanisms behind this trend that remain obscure at global scales.

Positive relationship between fruit removal by animals and seedling recruitment in a tropical forest

Fleshy-fruited plants rely on animal frugivores to disperse their seeds, and seed removal by frugivores may leave an imprint on seedling recruitment. However, to what extent plant–frugivore interactions are related to seedling recruitment has rarely been quantified at the community level, especially in species-rich tropical forests. In this study, we tested the effect of different plant traits on fruit removal by frugivores and tested the relative importance of fruit removal, plant traits and abiotic factors for seedling recruitment. We quantified plant–frugivore interactions of 22 fleshy-fruited plant species consumed by 56 diurnal frugivore species, and counted the number of seedlings that emerged along an elevational gradient in the Colombian Andes. We measured a set of plant traits (i.e., crop size; fruit size; seed load and mass; fruit nutritional contents), estimated the density of adult plants and recorded relevant abiotic factors (light, temperature and humidity). We found that fruit removal by frugivores was positively associated with crop size, but negatively associated with fruit length and unrelated to seed load and fruit nutritional content. Seedling densities were positively related to the density of adult plants, seed mass and fruit removal by animals. We found no relationship between abiotic factors and seedling recruitment. Our results indicate that fruit abundance and morphology are important determinants of fruit removal and that fruit removal is positively associated with seedling recruitment accounting for effects of species abundance and plant traits. We conclude that plant traits shape fruit removal and seedling recruitment at the community level, while these two crucial processes of forest regeneration are directly linked by seed dispersal of animals.