Nucleation in tropical ecological restoration

Abstract

Ecological theories of facilitation and nucleation are proposed as a basis for environmental restoration in tropical ecosystems. The main goal of this paper is to present restoration techniques based on the concept of nucleation, in which small nuclei of vegetation are established within a degraded land. The nucleation techniques (artificial shelters for animals, planting of herbaceous shrub life forms, soil and seed bank translocation, seed rain translocation, soil and seed rain translocation's seedling set, artificial perches, planting of native trees in groups, and ecological stepping-stones with functional groups) promote the landscape connectivity on two flows: inward: receiver connectivity and outward: donor connectivity. The nuclei development represents an alternative for restoration by prioritizing the natural processes of succession. This methodology appears to take long to generate vegetation corresponding to tropical climates, but is fundamental in the formation of communities capable of acting, in the future, as a new functional nuclei within the current fragmented landscape. This strategy also encourages greater integration between the theories and projects of ecological restoration for the development of human resources and to benefit the restoration practitioner. Key words: facilitation, succession, heterogeneity, landscape connectivity, degraded areas A Nucleação na restauração ecológica de ecossistemas tropicais RESUMO: As teorias ecológicas da facilitação e nucleação são propostas como base para a restauração ambiental de ecossistemas tropicais. Nesse "Ponto de Vista" apresentam-se técnicas de restauração fundamentadas no conceito de nucleação, onde pequenos núcleos de vegetação são implantados em uma área degradada. As técnicas de nucleação (abrigos artificiais para animais, plantio de espécies herbáceo-arbustivas, transposição de solo e banco de sementes, transposição de chuva de sementes, blocos de mudas procedentes de transposição de solo e chuva de sementes, poleiros artificiais, plantio de árvores nativas em grupos de Anderson, e trampolins ecológicos com grupos funcionais) promovem a conectividade da paisagem sob dois fluxos: interno: conectividade recebedora; e externo: conectividade doadora. O desenvolvimento dos núcleos representa uma alternativa de restauração que prioriza os processos de sucessão natural. A restauração através das técnicas de nucleação pode parecer muito lenta para atingir uma vegetação que corresponda ao clima tropical, porém representa uma base para a constituição de comunidades que, no futuro, poderão potencialmente atuar como novos núcleos funcionais dentro da atual paisagem fragmentada. Encoraja-se maior integração entre teorias ecológicas e projetos de restauração para desenvolvimento de recursos humanos e formação de restauradores ecológicos. Palavras-chave: facilitação, sucessão, heterogeneidade, conectividade da paisagem, áreas degradadas

Testing heterogeneity–diversity relationships in tropical forest restoration

“…Whereas a number of authors have suggested that habitat heterogeneity should be higher with a tree island planting approach (Rey Benayas et al 2008;Reis et al 2010;Corbin and Holl 2012), we know of no other studies that have directly compared this approach to more homogeneous restoration strategies. Past studies, however, have shown that other restoration strategies that are applied in a patchy manner (e.g., Baer et al 2004-fertilization and soil depth; Gundale et al 2006-forest thinning) can successfully restore small-scale nutrient heterogeneity.…”

“…These tree islands facilitate natural recovery processes in degraded landscapes, as they slowly expand, through growth of planted seedlings and increased dispersal and establishment of new seedlings, and may ultimately coalesce (Rey Benayas et al 2008). The method attempts to simulate nucleation processes that naturally occur in successional forest and may leave less of a legacy of planted trees (Yarranton and Morrison 1974;Reis et al 2010). Indeed, our past research in the neotropics indicates that planted tree islands serve to attract and provide habitat for animals, which encourages zoochorous seed dispersal and seedling establishment (Zahawi and Augspurger 2006;Cole et al 2010;Zahawi et al 2013).…”

“…Several authors have suggested that planting tree islands should result in higher small-scale habitat heterogeneity and in turn more diverse species composition compared to conventional plantation-style restoration (Rey Benayas et al 2008;Reis et al 2010;Corbin and Holl 2012), but this has never been tested experimentally. We compared three restoration strategies (control-no planting, planting tree islands, conventional mixed-species tree plantations) to test three hypotheses: (1) planting tree islands results in greater heterogeneity of vegetation structure (canopy and understory) and soil nutrients than control or plantation treatments; (2) greater habitat heterogeneity results in more tree species recruiting; and (3) tree diversity is more strongly correlated with resource heterogeneity than mean resource availability.…”

Effects of flooding and its temporal variation on seedling recruitment from the soil seed bank of a Neotropical floodplain

“…Upon completion of their reproductive cycle, annual plants die, thereby giving room to other species (Reis et al 2010). Therefore, the fast emergence of annual species can favor the entire postflood succession (Lortie & Turkington 2008).…”

Custeio das atividades das técnicas de nucleação implantadas nas clareiras abertas pela exploração petrolífera na Amazônia central

“…Nucleation is understood as the capacity of species to provide significant improvement in environmental quality, increasing the probability of occupation of this environment by other species (Yarranton and Morrison, 1974;Reis et al, 2010).…”