We reviewed the evidence on the role of ants as plant biotic defenses, by conducting meta-analyses for the effects of experimental removal of ants on plant herbivory and fitness with data pooled from 81 studies. Effects reviewed were plant herbivory, herbivore abundance, hemipteran abundance, predator abundance, plant biomass and reproduction in studies where ants were experimentally removed (n = 273 independent comparisons). Ant removal exhibited strong effects on herbivory rates, as plants without ants suffered almost twice as much damage and exhibited 50% more herbivores than plants with ants. Ants also influenced several parameters of plant fitness, as plants without ants suffered a reduction in biomass (-23.7%), leaf production (-51.8%), and reproduction (-24.3%). Effects were much stronger in tropical regions compared to temperate ones. Tropical plants suffered almost threefold higher herbivore damage than plants from temperate regions and exhibited three times more herbivores. Ant removal in tropical plants resulted in a decrease in plant fitness of about 59%, whereas in temperate plants this reduction was not statistically significant. Ant removal effects were also more important in obligate ant-plants (=myrmecophytes) compared to plants exhibiting facultative relationships with hemiptera or those plants with extrafloral nectaries and food bodies. When only tropical plants were considered and the strength of the association between ants and plants taken into account, plants with obligate association with ants exhibited almost four times higher herbivory compared to plants with facultative associations with ants, but similar reductions in plant reproduction. The removal of a single ant species increased plant herbivory by almost three times compared to the removal of several ant species. Altogether, these results suggest that ants do act as plant biotic defenses, but the effects of their presence are more pronounced in tropical systems, especially in myrmecophytic plants.
Including ecosystem functions into restoration ecology has been repeatedly suggested, yet there is limited evidence that this is taking place without bias to certain habitats, species, or functions. We reviewed the inclusion of ecosystem functions in restoration and potential relations to habitats and species by extracting 224 publications from the literature (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013). Most studies investigated forests, fewer grasslands or freshwaters, and fewest wetlands or marine habitats. Of all studies, 14% analyzed only ecosystem functions, 44% considered both biotic composition and functions, 42% exclusively studied the biotic component, mostly vascular plants, more rarely invertebrates or vertebrates, and least often microbes. Most studies investigating ecosystem functions focused on nutrient cycling (26%), whereas productivity (18%), water relations (16%), and geomorphological processes (14%) were less covered; carbon sequestration (10%), decomposition (6%), and trophic interactions (6%) were rarely studied. Monitoring of ecosystem functions was common in forests and grasslands, but the functions considered depended on the study organisms. These associations indicate research opportunities for certain habitats, species, and functions. Overall, the call to include ecosystem functions in restoration has been heard; however, a lack of clarity about the ecosystem functions to be included and deficits of feasible field methods are major obstacles for a functional approach. Restoration ecology should learn from recent advances in rapid assessment of ecosystem functions, and by a closer integration with biodiversity-ecosystem functioning research. Not all functions need to be measured in all ecosystems, but more functions than the few commonly addressed would improve the understanding of restored ecosystems.
A single tropical plant species can harbour hundreds of endophyte species within its tissues. Beyond this, little is known about the relationship between endophyte colonization, leaf traits and spectral properties of leaves. We explore these relationships in Coccoloba cereifera, a plant well known for its symbiotic properties. Endophyte richness in C. cereifera was statistically correlated with leaf traits such as water content, the ratio of fresh weight/dry weight and polyphenol/leaf specific weight. Endophyte diversity was also related to spectral vegetation indices of chlorophyll content. The associations among endophyte diversity, leaf traits and spectral reflectance pose new questions and present new opportunities to better understand plant-fungal symbioses and related leaf optical properties.
ABSTRACT(Distribution of the endophytic fungi community in leaves of Bauhinia brevipes (Fabaceae)). Endophytic fungi represent large, yet unexplored components of biodiversity. Th is work evaluated the richness and the distribution of endophytes in the leaves of Bauhinia brevipes (Fabaceae). A total of 1110 colonies were recovered from the samples and grouped by their morphological traits into 126 taxa. Th e total number of taxa according to leaf development was: 102 in mature leaves, 93 in recently expanded leaves and 79 for unfolded leaves. Th e major endophyte genera were Phomopsis, followed by Dothiorella, Pestalotiopsis and Acremonium. Th e richness and the isolate numbers of endophytes were not statistically aff ected by leaf region. However, some taxa were leaf-age specifi c; six were isolated only from unfolded leaves, nine from recently expanded leaves and 17 were exclusively found in mature leaves. Th e composition of endophytes varied with leaf region; the similarities (Jaccard's Index) among the leaf regions of diff erent leaf ages ranged from 0.36 to 0.46, indicating a high spatial variation in the community of endophytic fungi inside the leaves. Th e high richness of endophytes in this host plant highlights a signifi cant contribution of fungi to tropical biodiversity and the need for further research in this area.
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