Defaunation as a trigger for the additional loss of plant species in fragmented landscapes: considerations on the state of Espírito Santo, southeastern Brazil

Abstract

Here we present a brief review on how the loss of fauna can cause a concomitant loss in plant diversity in the state of Espírito Santo, focusing on the context of current habitat loss and fragmentation and the importance of the mutualistic interactions between animals and plants. We discuss the main groups of fauna that are involved in pollination and seed dispersal, especially those that are found in the state of Espírito Santo. These ecological processes were selected due to their relevance for population dynamics and population genetics of plants. In Atlantic Forest, important pollinators include a variety of insects (especially bees), along with many species of birds and bats. Seed dispersers also include many taxonomic groups, from ants to large mammals. Each of these groups contribute in their own unique and complementary, rather than redundant, way. Habitat fragmentation causes a variety of problems for habitat integrity and the reduction of species diversity, and smaller fragments tend to support fewer species and smaller populations. As a consequence, pollinators and seed dispersers are lost or their activity is reduced, thereby reducing even further the reproductive success of the plants, leading to a vicious cycle of reduction of species diversity. Key words: animal-plant interaction, fragmentation, habitat loss, pollination, seed dispersal. ResumoO presente trabalho apresenta uma breve revisão sobre como a perda de fauna pode causar a perda concomitante de diversidade vegetal no estado do Espírito Santo, considerando o cenário atual de perda e fragmentação de habitats e a importância das interações mutualísitcas entre animais e plantas. Foram considerados os principais grupos zoológicos envolvidos na polinização e na dispersão de sementes, especialmente aqueles com ocorrência no estado do Espírito Santo. Estes processos ecológicos foram selecionados devido à sua relevância na dinâmica e a genética populacional das plantas. Na Mata Atlântica, importantes polinizadores incluem uma variedade de insetos (especialmente abelhas), juntamente com muitas espécies de aves e morcegos. Os dispersores de sementes também abrangem muitos grupos taxonômicos, desde formigas até grandes mamíferos. Cada um desses grupos contribui de maneira única e complementar, mais do que de forma redundante. A fragmentação de habitats compromete a integridade do habitat e reduz a diversidade de espécies, ressaltando que fragmentos menores tendem a suportar menos espécies e menores populações. Como consequência, os polinizadores e os dispersores de sementes são perdidos ou sua atividade é reduzida, diminuindo ainda mais o sucesso reprodutivo das plantas, levando a um círculo vicioso de redução da diversidade de espécies. Palavras-chave: interação animal-planta, fragmentação, perda de habitat, polinização, dispersão de sementes.

Frugivore diversity increases evenness in the seed rain on deforested tropical landscapes

“…Although the pattern of diversity detected in the seed rain may not translate directly into patterns of plant recruitment and community regeneration (Reid and Holl 2017, but see Carlo and Morales 2012, González‐Castro et al 2012) our findings were remarkably consistent across sites. This suggests that antiapostatic seed dispersal is a common pattern influencing the seed rain of tropical communities.…”

“…Generalist birds that feed on both fruits and insects are among some of the most abundant types of birds in fragmented landscapes (Pizo and dos Santos 2017, Carlo and Morales 2012). Such birds prefer lipid‐rich fruits that provide a greater energy reward (Moermond and Denslow 2012, Stiles 1998).…”

“…Recent studies have found that decreases in frugivore richness lead to the loss of interactions and co‐extinction of plant species (Caughlin et al 2012, Srbek‐Araujo et al 2017, Emer et al 2012, Morán‐López et al 2002), or changes in the genetic diversity of plant populations (Carvalho et al 2012, Pérez‐Méndez et al 2017). Tropical forest regeneration and resilience are also affected by frugivore activity and diversity (Gardner et al 2012, González‐Castro et al 2012, Albert et al 2020), which ultimately can affect carbon sequestration of remnant forests (Bello et al 2015) and restoration plantations (Brancalion et al 2018).…”

Floristic survey in an Atlantic Forest remnant in the Recôncavo da Bahia, Bahia State, Brazil

“…(Orchidaceae) that is threatened with extinction and Heteropterys sanctorum W.R.Anderson (Malpighiaceae) that is critically endangered (BFG 2015). In most cases, the risk of extinction or disappearance of species is related to human activities and unsustainable use of natural resources, which culminate in the degradation of habitats and the disappearance of species (Penedo et al 2015, Srbek-Araujo et al 2017. The only species that were sampled at the three intervals (decades of 50, 70 and the present) are species of wide distribution, as for example, Psychotria deflexa DC.…”

Seeds and the City: The Interdependence of Zoochory and Ecosystem Dynamics in Urban Environments

“…areas (Fey et al, 2016; that roads restrict animal movements enhancing the fragmentation and isolation of urban green patches, and further delineating the habitat mosaic. Smaller, more isolated, fragments tend to support fewer animal disperser species and smaller population sizes in urban areas (Srbek-Araujo et al, 2017), leading to lower fruit removal rates, as found for cactus fruit removal rates by mammals (Ness et al, 2016). If small, isolated fragments are avoided by animals, it is also likely that seed influx into isolated fragments may decline, eventually leading to local extirpation of certain plant species.…”