Breaking Barriers of Regeneration: Examining the Effectiveness of Bird Perches in Facilitating Seed Dispersal in a Tropical Dry Forest

This project examined the use of bird perches in facilitating seed dispersal to address the lack of seed dispersal and seed rain in degraded tropical forests. The goal of this project was to learn more about this practice in order to derive more realistic expectations of its effectiveness. After four months, significantly more seeds were dispersed into plots containing introduced perches as compared to subplots that lacked perches. Seed rain was dominated by Ficus citrifolia, a mid-level successional species, indicating that introduced artificial perches may influence the regeneration of more mature forests. Seeds recovered from seed traps represented species with close proximity to the plots. Seeds dispersed beneath perches were correlated positively with those occurring in surrounding forests. There were eight bird species recorded utilizing perches. Bird species found utilizing perches were also positively correlated with those found within surrounding forest. These results suggest that bird perches in tropical forests may have a very local effect in that species dispersed may be limited to those found in close range to perch structures, but that the perches are effective at providing a seed rain of those species

Evolution and Maintenance of Plumage Polymorphism: the case of the Red-footed booby (Sula sula)

The red-footed booby (Sula sula) is considered one of the most polymorphic seabirds, with three recognized major adult plumage types: (1) white; (2) white-tailed brown; and (3) brown, and several degrees of intermediates. The ratio of these color morphs varies among populations, with the white morph typically predominating. However, there are a few populations that present an inversed ratio of color morphs, such as Isla Europa in the Indian Ocean and the Galapagos archipelago, with the white-tailed brown or brown morphs predominating. I studied natural populations of red-footed boobies from three geographic locations, namely, the Galapagos archipelago, Johnston Atoll in the Pacific Ocean, and the Fernando de Noronha archipelago in the South Atlantic Ocean, to investigate the genetic basis of plumage polymorphism as well as possible mechanisms maintaining the polymorphism and variation in the ratios of color morphs. To determine the genetic basis of the polymorphism, I investigated the role played by the candidate locus Melanocortin-1 receptor (MC1R). By examining alleles in the MC1R locus in the context of phylogeny of the Sulidae family, I investigate the scope of involvement of the MC1R locus in determining the different plumage colors and patterns among the ten species in this family. Several potential mechanisms maintaining the polymorphism and the differential ratio of color morphs among locations were evaluated; both selective and neutral mechanisms were explored, such as non-random mating and limited gene flow, as well as historical evolutionary events such as founder effect and bottleneck events

Do subtropical seasonal forests in the Gran Chaco, Argentina, have a future?

While much information is available about tropical and temperate ecosystems, there is a remarkably little information as to land cover and land use changes in the subtropical biomes of the world. Here, we quantify changes in the spatial patterns of land cover types at the southern edge of the seasonally dry, subtropical Chaco forest of South America during the second half of the 20th century using a vegetation map printed in 1969 and a Landsat TM based digital map produced 30 years later. Results show a massive contraction of forest; ca. 1.2 million ha of original lowland and mountain subtropical dry forests and woodlands, 85% of the total, have been cleared in only 30 years. This loss of Chaco forests of 2.2% year1 is consistent with or even exceeds, global trends. Forest vegetation now persists as fragments where there was formerly continuous cover. Most of undisturbed Chaco forest has now been converted to pasture or is undergoing secondary succession. Today, these new vegetation types, resulting mainly from agricultural expansion, have increased 10-fold in cover and now represent the commonest land cover types. The increased intensity of agricultural usage, possibly triggered by an increase in annual rainfall during the last decades, has been accompanied by changes in agricultural practices and a relative decline in the rural population.Fil: Zak, Marcelo Román. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Cabido, Marcelo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Hodgson, John G.. Peak Science and Environment, Station House; Reino Unido. University of Sheffield; Reino Unid

Novel ecosystems: theoretical and management aspects of the new ecological world order

We explore the issues relevant to those types of ecosystems containing new combinations of species that arise through human action, environmental change, and the impacts of the deliberate and inadvertent introduction of species from other regions. Novel ecosystems (also termed 'emerging ecosystems') result when species occur in combinations and relative abundances that have not occurred previously within a given biome. Key characteristics are novelty, in the form of new species combinations and the potential for changes in ecosystem functioning, and human agency, in that these ecosystems are the result of deliberate or inadvertent human action. As more of the Earth becomes transformed by human actions, novel ecosystems increase in importance, but are relatively little studied. Either the degradation or invasion of native or 'wild' ecosystems or the abandonment of intensively managed systems can result in the formation of these novel systems. Important considerations are whether these new systems are persistent and what values they may have. It is likely that it may be very difficult or costly to return such systems to their previous state, and hence consideration needs to be given to developing appropriate management goals and approaches.Ctr Invas Bio

Rainforests at the beginning of the 21st century

Rainforests are situated at low latitude where forests enjoy steady and strong radiation. Biodiversity in rainforests has been very high, for historical and climatic reasons. The number of species is very high and tends to increase with precipitation and decrease with seasonality. Disturbance, soil fertility and forest stature also influence the species richness and high turnover of species contribute to diversity. Field observation and studies revealed that large scale deforestation could alter the regional and global climate significantly. Deforestation alters the surface albedo which leads to climate change. Regional land use contributes to climate change through surface-energy budget, as well as the carbon cycle. Forest fragmentation, logging, overhunting, fire and the expanding agriculture threaten the biodiversity. Rainforest covered area has significantly shrunk in the last decades. It is hard to protect the forests because of the growing demand for agricultural area and forest-derived products. Most measures proved ineffective to slow down the destruction. Hence, more forest will be lost in the future. Conservationists should take into consideration the secondary forests because biodiversity can be high enough and it is worth protecting them

A limited seed bank in both natural and degraded tropical peat swamp forest: the implications for restoration

Carbon-rich tropical peat swamp forests (PSFs) are being degraded at an alarming rate. In response to national and global agendas, landscape-scale PSF restoration is underway, although supporting knowledge of PSF ecosystem restoration ecology remains limited. Seed banks are usually an important source of natural regeneration and crucial in post-degradation forest recovery, even in the humid tropics where reduced seed dormancy leads to typically smaller seed banks than in temperate regions. It has been assumed that PSF degradation reduces the seed bank, limiting natural regeneration, but this has not previously been investigated explicitly. This study of PSF in Central Kalimantan explored seed bank prevalence and regenerative capacity across five forest zones (FZs): degraded, open canopy disturbed, edge, closed canopy disturbed and natural. Numbers and species of seeds and seedlings were recorded from surface peat samples collected from each FZ over one year. Seed density, averaged across FZs, was 41 seeds m-2; total species number was 11; and seedling density was 16.0–73.6 m-2 depending on FZ. These values were much lower than for other forests in this region. There was little difference in seed bank size between natural and degraded FZs, and only the forest edge showed higher than expected seed bank regenerative capability. Overall, our results suggest that seed banks are not of high importance in tropical PSF regeneration, either before or after degradation. These findings are discussed from the perspective of successional traits in different species and their relevance to ecosystem restoration

Distúrbios naturais e antrópicos em remanescentes da floresta com Araucaria

Orientador: Prof. Dr Franklin GalvãoCoorientadoras: Profa. Drª Márcia C. M. Marques, Profa. Drª Sandra Bos MikichTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Engenharia Florestal. Defesa : Curitiba, 12/03/2018Inclui referênciasÁrea de concentração: Conservação da naturezaResumo: A Floresta Ombrófila Mista (FOM), também conhecida como Floresta com Araucária (FA), foi drasticamente reduzida ao longo do último século, durante a colonização do Sul do Brasil. Atualmente, os remanescentes encontram-se fragmentados e, em muitos deles, preponderam densas populações da taquara-lixa, Merostachys skvortzovii, uma espécie nativa com desenvolvimento agressivo. Um dos grandes temas da atualidade são as mudanças climáticas e seus efeitos sobre as populações animais e vegetais.Tais mudanças atingem a temperatura do ar e os regimes de chuvas, assim como a frequência e intensidade de eventos climáticos extremos, como ciclones, vendavais e downbursts, dentre outros. Registros históricos comprovam o aumento na frequência e intensidade desses eventos, cada vez mais devastadores. Áreas de FOM fragmentadas, com a presença da taquara lixa no sul do Brasil e atingidas por um ciclone extratropical em setembro de 2009, foram objeto da presente tese, que foi estruturada em três capítulos. O capítulo 1 contemplou a avaliação da mortalidade em comunidades florestais, antes e depois da passagem do ciclone extratropical. Neste capítulo verificou-se que a mortalidade não está relacionada à densidade da madeira e ao porte dos indivíduos, mas sim ao grupo ecológico, às características da paisagem e à distância da borda. Assim, a vegetação em locais situados em cristas de morros e pequenos fragmentos foram mais sensíveis à passagem de ciclones que áreas de baixadas e grandes fragmentos. No capítulo 2 foram avaliadas a composição florística, a diversidade, as taxas demográficas e o incremento (em diâmetro) de árvores após a passagem do ciclone e da superdominância de M. skvortzovii. A passagem do ciclone proporcionou um aumento da riqueza, com entrada de espécies não registradas anteriormente, porém houve uma redução na diversidade, causada pela maior abundância de algumas espécies pioneiras após o ciclone. A passagem do ciclone afetou a mortalidade, o recrutamento, o turnover de espécies, a perda e o ganho de área basal, bem como o incremento (em diâmetro) das árvores sobreviventes. A presença de populações de M. skvortzovii não afetou individualmente as taxas demográficas. No capítulo 3, cinco fragmentos de FOM são avaliados para verificar se existiam diferenças entre variáveis estruturais e guildas funcionais. Verificou-se que a ocupação por taquaras influenciou negativamente as variáveis estruturais (abundância, riqueza e área basal) e guildas funcionais (espécies pioneiras, dispersão abiótica e dossel). Por outro lado, o tamanho dos fragmentos e a distância da borda não apresentaram relação com as variáveis estruturais ou as guildas funcionais. No conjunto, os resultados demostram que os distúrbios, naturais e/ou antrópicos, podem ser grandes geradores de alterações dos processos ecológicos, com casos de intensificação ou repressão dos processos dinâmicos. A conservação dos remanescentes de FOM passa pela necessidade de manutenção de fragmentos em bom estado de conservação além do estabelecimento de conexão entre fragmentos ao longo da paisagem. Palavras-chave: Tempestade subtropical. Taxas demográficas. Estrutura de comunidades. Fragmentação. Paisagem. Atributos funcionais.Abstract: The Mixed Ombrophilous Forest, also known as Araucaria Forest (AF) was highly reduced through the last century, during the colonization of Southern Brazil. At present, the AF remnants are fragmented, and in most of them there are dense populations of a native but highly aggressive bamboo species, Merostachys skvortzovii. A worldwide top priority issue is the so-called climate change and its effects in animal and plant populations around the globe. Such phenomenon affects air temperature and rainfall regime, as well as frequency and intensity of extreme climatic events, such as cyclones, windstorms and downbursts. Historical records reveal an increase in frequency and intensity of such increasingly devastating events. Areas of AF fragments, with the presence of taquara-lixa in southern Brazil and hit by an extratropical cyclone in September 2009 constituted the basis and the background of the present thesis, divided into three chapters. Chapter 01 examines the mortality in forest communities, before and after the cyclone. We found that mortality was not related to wood density or plant size, but to ecological groups, landscape features and distance from the edge. Thus, the vegetation situated in hilltops and small fragments is more exposed to cyclones than those in valleys and big fragments. In Chapter 02 we evaluated the floristic composition, diversity, demographic rates and increment of trees after the cyclone hit the study area and the superdominance of M. skvortzovii. The cyclone caused an increase in plot richness, with an input of new species. Nevertheless, we also observed a decrease in diversity as a result of the high abundance of some pioneer species after the cyclone. It also affected mortality, recruitment, species turnover, and the gain and loss in basal area, as well as tree increment. The presence of populations of M. skvortzovii alone did not affect demographic rates. On Chapter 03 we assessed differences between structural variables and functional guilds in five fragments of AF. We found that occupation by bamboos negatively affected structural variables (abundance, richness and basal area) and functional guilds (pioneer species, non-zoochorous species and canopy). Conversely, fragment size and distance from the edge did not show any relation with structural variables or functional guilds. In general, the results demonstrate that natural and/or human-induced disturbances can be important drivers of ecological processes, improving or supressing dynamic processes. The conservation of the remnants of FOM requires the maintenance of fragments in a good state of conservation besides the establishment of connection between fragments along the landscape. Key-words: Subtropical storm. Demographic rates. Community structure. Fragmentation. Landscape. Functional attributes

Diferenças edáficas e estruturais entre duas florestas estacionais no bioma Cerrado

Comparative studies between semideciduous (SSF) and deciduous (DSF) seasonal forests in the Cerrado biome are rare. Two fragments were selected along the slopes of Araguari River valley in western Minas Gerais State (southeastern Brazil), in order to investigate the difference between these two types of seasonal forests. Both fragments are geographically close to each other, with similar environmental conditions. Sixty replicate plots of 20 x 10 m were located within each stand and all woody plants, larger than 5 cm diameter at breast height (dbh), were surveyed. Soil samples were collected and their physical and chemical characteristics were analyzed. Soil water content was estimate for three depths seasonal samples (dry and wet condition). The results indicate that two seasonal forests on the lithosols differ significantly as to the water regimes throughout the year as well as to soil texture and chemical elements. Each forest presented an idiosyncratic set of edaphic specialist species and suggests predictable shifts in composition, diversity and dominance in each site. The arboreal structural differences among two forests were low. This study showed that differences between two seasonal forest types can be explained by edaphic condition. Confirmed this tendency in large scale, these two types of seasonal forests requires specific programs of studies, management and conservation actions in Cerrado. Key words: seasonally dry tropical forest, deciduous seasonal forests, semideciduous seasonal forests, Cerrado biome.Os estudos comparativos entre as florestas estacionais semideciduais (FS) e deciduais (FD) no bioma Cerrado são raros. Para avaliar as diferenças quanto aos aspectos edáficos e estruturais desses dois tipos de florestas estacionais, foram escolhidos dois fragmentos que se localizam sobre neossolos litólicos nas encostas do vale do rio Araguari, oeste do estado de Minas Gerais. Os dois fragmentos se localizam muito próximos espacialmente e apresentam algumas condições ambientais semelhantes entre si. O componente arbóreo (>15 cm CAP) foi amostrado em 60 parcelas 20 x 10 m, os teores de nutrientes e a textura dos solos, determinados em amostras superficiais (0-20 cm); e a umidade do solo, em amostras sazonais em três profundidades (0-10 cm, 20-30 cm e 40-50 cm). Os resultados demonstraram que os solos das duas florestas diferiram significativamente quanto à capacidade de reter umidade no solo ao longo do ano e quanto à textura e teores dos elementos químicos no solo. Cada floresta apresentou um conjunto próprio de espécies edafoespecialistas, que influenciaram na composição, diversidade e dominância em cada sítio. As duas fitofisionomias diferiram pouco quanto à estrutura do componente arbóreo. Concluiu-se o estudo, ratificando que as duas florestas estacionais diferem entre si quanto a vários aspectos que se devem muito às condições edáficas de cada sítio. Confirmada essa tendência em ampla escala, os dois tipos de florestas estacionais não podem ser consideradas uma mesma fitofisionomia, o que normalmente ocorre, fato conclusivo que exige, portanto, elaboração de planos de conservação e manejo específicos. Palavras-chave: florestas tropicais estacionais, floresta estacional semidecidual, floresta estacional decidual, Cerrado, Minas Gerais