Impacts of a large hydroelectric dam on the Madeira River (Brazil) on floodplain avifauna

ABSTRACT Hydroelectric dams represent an important threat to seasonally flooded environments in the Amazon basin. We aimed to evaluate how a dam in the Madeira River, one of the largest tributaries of the Amazonas River, affected floodplain avifauna. Bird occurrence was recorded through simultaneous passive acoustic monitoring in early successional vegetation and floodplain forest downstream from the dam and upstream in sites impacted by permanent flooding after dam reservoir filling. Species were identified through manual inspection and semi-automated classification of the recordings. To assess the similarity in vegetation between downstream and upstream sites, we used Landsat TM/ETM+ composite images from before (2009-2011) and after (2016-2018) reservoir filling. Downstream and upstream floodplain forest sites were similar before, but not after dam construction. Early successional vegetation sites were already different before dam construction. We recorded 195 bird species. While species richness did not differ between upstream and downstream sites, species composition differed significantly. Ten species were indicators of early successional vegetation upstream, and four downstream. Ten species were indicators of floodplain forest upstream, and 31 downstream. Seven of 24 floodplain specialist species were detected by the semi-automated classification only upstream. While we found some bird species characteristic of early successional vegetation in the upstream sites, we did not find most species characteristic of tall floodplain forest. Predominantly carnivorous, insectivorous, and nectarivorous species appear to have been replaced by generalist and widely distributed species.

Plant diversity and community composition in managed humid coastal dune slacks in NW England

Humid coastal dune slacks are an endangered habitat in Northwestern Europe. In the UK, dune slacks are currently classified as being in ‘unfavourable’ condition, with projected decrease in England of up to 30% by 2036. Studies in mainland Europe suggest that regional factors (e.g. slack area, age, and isolation) are more important than local factors (e.g. soil, pH, soil nutrient and water status) in driving successional vegetation processes in coastal slacks. However, this has never been tested for the UK, where approximately 14% of European slacks occur. We used previously established survey protocols to test whether regional factors are more important than local factors in UK coastal slacks, along the Sefton Coast in NW England. We found that slack area and slack age were more important than local factors in driving plant community composition and species richness. We also showed that higher levels of management, such as active grazing and invasive shrub and tree removal, are effective in increasing soil moisture levels in slacks. Our results suggest that similar successional processes are likely to be important in slacks in the NW of England, compared to mainland Europe.

Struktur dan Komposisi Vegetasi pada Suksesi di Muara Sungai Unda, Kabupaten Klungkung, Bali

Letusan Gunung Agung pada tahun 1963 memberikan dampak ekologis di sekitar muara Sungai Unda, Kabupaten Klungkung, Bali. Lahar yang mengalir melalui sungai tersebut menyebabkan terjadinya suksesi primer akibat tutupan pasir dan batu. Selama 57 tahun, muara Sungai Unda tidak hanya mengalami suksesi alam, tetapi juga mengalami suksesi antropogenik melalui pemanfaatan sebagai tambang pasir, lahan pastura, dan permukiman sementara. Penelitian ini bertujuan untuk mempelajari struktur dan komposisi vegetasi pada suksesi di muara Sungai Unda. Penentuan struktur vegetasi dilakukan pada 8 stasiun penelitian dengan menggunakan metode plot dengan jumlah 24 plot pohon (20 x 20 m) dan 48 plot vegetasi lantai (1 x 1 m). Data dianalisis menggunakan parameter ekologis seperti densitas, densitas relatif, frekuensi, frekuensi relatif, dominansi, dominansi relatif, dan nilai penting, serta dilengkapi dengan indeks keragaman Shannon-Weiner (H’), indeks dominansi (C), dan indeks keseragaman (E). Hasil penelitian menunjukkan bahwa semak dan rumput merupakan bentuk hidup yang paling menentukan struktur vegetasi di Muara Sungai Unda. Beberapa spesies penyusun vegetasi tersebut merupakan tumbuhan invasif seperti yang harus dikontrol populasinya adalah Typha angustifolia, Ipomoea carnea, Chromolaena odorata, Lantana camara, dan Vachellia farnesiana. Berdasarkan indeks yang digunakan, keanekaragaman vegetasi termasuk dalam kategori tinggi, tanpa ada jenis yang mendominasi, dengan persebaran yang merata.Kata kunci: Gunung Agung; spesies invasive; suksesi antropogenik; vegetasi suksesiStructure and Composition of Successional Vegetation in Unda River, Klungkung Regency, BaliABSTRACTMount Agung eruption in 1963 caused major ecological impact around Unda River, Klungkung Regency, Bali. The volcanic mudflow that surpass the Unda River watershed initiate the primary succession in those areas. This research aimed to study the structure and composition of successional vegetation in Unda River. Twenty-four tree plots (20 x 20 m) and 48 understorey plots (1 x 1 m) derived from 8 research stations were used to determine the structure of vegetation. The data analyzed by ecological parameters, such as density, relative density, frequency, relative frequency, dominancy, relative dominancy, and importance value, then completed with Shannon-Weiner diversity index (H’), dominancy index (C), and evenness index (E). The results shown that the vegetation structure in Unda River determined by two major growth form: shrubs and grasses. Some notable invasive species that should be controlled are Typha angustifolia, Ipomoea carnea, Chromolaena odorata, Lantana camara, and Vachellia farnesiana. Based on the three indexes, the vegetation diversity was categorized as high diversity, without any species domination, and the distribution of the species are uniformKeywords: Anthropogenic succession; invasive species; Mount Agung; successional vegetation

Odonata species diversity, distributions, and status in a rare sand prairie-savanna wetscape

Inland sand areas scattered across the North American eastern deciduous forest and western tallgrass prairie ecotone are known for supporting pyrogenic early-successional vegetation and specially adapted terrestrial faunas. Many of these globally and regionally rare systems contain functionally connected wetland networks (“wetscapes”) potentially important for aquatic insects. Sampling adults, nymphs, and exuviae in a remnant sand prairie-savanna wetscape in Illinois, USA, I assessed odonate species diversity (alpha, gamma, beta), distributions (spatial, temporal, abundance), and rarity status. In one field season (12 sites, 12 visits) I found more than a third of Illinois odonate species and close to half of the state’s lentic breeding odonates, including a new state record (Erythemis vesiculosa). Richness averaged 25.8 species per site, reducing to 12.4 species with removal of nonbreeding occurrences. Three sites including a shrub swamp, beaver pond, and forested vernal depressions complex made significant contributions to beta diversity, dependent on general versus breeding occurrences. Majorities of Anisoptera species (70%) and Zygoptera species (53%) bred at three or fewer sites. Eight species flew during all or most of the study period (late May to early October) whereas 14 species were detected on a si ngle survey. Status classification derived from the observed spatial, temporal, and abundance distributions resulted in 24 common or very common species, 20 uncommon or rare species, and 10 vagrants across the wetscape. These context-specific classifications may be combined with diversity and breeding patterns and other information in wetscape prioritization schemes.

Pentas lanceolata (Egyptian starcluster).

Pentas lanceolata is a fast growing, small to medium-sized herbaceous shrub that has become very popular as an ornamental and potted plant due to its colourful flowers. It is adapted to grow in a wide range of environmental conditions and tolerates a fair amount of drought. P. lanceolata has been intentionally introduced into many tropical and subtropical regions from where it has escaped to colonize predominantly disturbed sites, open grounds and roadsides near cultivation areas. Once established this species may become dominant in some open areas and can form monospecific stands with the potential to outcompete and exclude native plant species and other early successional vegetation. To date, P. lanceolata has been listed as invasive only in insular ecosystems in Hawaii, Anguilla, Norfolk Island, Mayotte Island and French Polynesia. In Hawaii, it has recently been noted spreading across the Big Island; on Maui, it volunteers in scrub areas and steep banks.

Physico-Chemical Characterization of Soil in a Tropical Landscape Restored by a Vegetal Succession

The objective was to evaluate the physicochemical composition of soils and their relationship with successional vegetation. The study was conducted in the area of influence of fluvial volcanic muds in the central region of Colombia. The physical variables of texture, porosity, humidity, color, apparent density, real density; and chemical variables of pH, organic matter, cation exchange capacity, major elements, minor elements, Al saturation, base saturation, Ca/Mg relation, (Ca+Mg)/K relation, and Mg/K relation were analyzed. A multivariate analysis between variables and descriptive of the soil–vegetation relationship was carried out. Physically, there was a negative correlation between apparent density with %porosity and real density with humidity content. The texture was classified as sandy loam and the structure as granular-crumbly type. Chemically, there was a negative correlation between pH, Mg/K relation, (Ca+Mg)/K relation, and Al saturation; a positive correlation between P, Mn, Ca, Zn, Fe, Mg, and base saturation. Furthermore, Na and K did not show any interaction relationship. The predominant plant species are distributed in the families Fabaceae, Asteraceae, Malvaceae, Euphorbiaceae, Cyperaceae, and Poaceae. The physical and chemical characteristics of the soil present conditions that allow the establishment and continuation of successional vegetation with a dominance of tree and shrub growth habit.

Spatiotemporal variation in pollinator taxa on the santa ana river wooly star Eriastrum densifolium ssp. Sanctorum (Milliken) mason (Polemoniaceae)

Flood control, via the construction of the Seven Oaks Dam in the Santa Ana River in southern California, has altered habitat in the downstream alluvial wash community and jeopardized the persistence of pioneer plant species that rely on periodic flood-scouring and sand recharge. One species, Eriastrum densifolium ssp. sanctorum (“Eriastrum”), an endangered perennial, has been greatly affected and persists in spatially separated populations on successional vegetation terraces. We made “dawn to dusk” observations of pollinators in three phenological stages at four sites, representing young and old seral stages, to identify primary pollinators and to elicit daily, site, and seasonal patterns of visitors. Data were compared to previous observations and correlated with annual rainfall to determine long-term trends. Shifts in pollinator taxa have occurred, with some consistency through time and space, during nine years. The sites with the highest pollinator abundance (older sites) are least suited to Eriastrum. Hummingbirds (prevalent in early season) and the Acton giant flower-loving fly (prevalent in late season) have been consistently present across years, whereas other taxa have varied. A shift from native bees to non-native bees has occurred, although native bees in the families Halictidae and Apidae (Micranthophora and Melissodes) remain important. In general, there was no correlation between taxa abundance and rainfall. Eriastrum appears to be a generalist able to take advantage of the behaviour, cycling, and availability of diverse pollinators daily, seasonally, and annually.

Spontaneous development of early successional vegetation improves Norway spruce forest soil after clear-cutting and renewal failure: a case study at a sandy-soil site

Clear-cutting is the most common silvicultural system. Sometimes, if the new crop is not established successfully, clearcut is left unreforested. This study focused on a site where early successional species such as silver birch (Bi) and rowan (Ro) were accompanied with Norway spruce (Sp) in 13-year-old stand from natural regeneration at 550 m of altitude at an acidic site with eastern aspect and 25% slope. We found five types of stand composition: treeless gaps, Ro-Bi, Ro-Bi-Sp, Bi-Sp and monospecific Sp. Besides these juvenile ones, adjacent 100-year-old spruce (Sp old) stand representing pre-harvesting conditions was studied. In addition to the performance of trees, organic layer (Hum), topsoil (Ah) and upper subsoil (B) horizons were sampled to study an expected shift of chemical properties after clear-cutting and secondary succession at the site of interest. Birch dominated the natural regeneration; rowan and spruce were present mostly in understorey. Old spruce was more acidic and nutrient-poorer compared to the juvenile treatments. The treeless treatment showed also slightly higher pH and comparable nutrients compared to the young mixtures. Young spruce was higher in nitrogen compared to Ro-Bi-Sp mixture.

The nature of open ecosystems

If open ecosystems were of recent anthropogenic origin, linked to human activity in the last millennia, they should support an impoverished biota assembled in large part from forest-dwelling species. Yet several of the world’s biodiversity hotspots are open ecosystems, rich in species and rich in endemics. This chapter introduces the diversity of open ecosystems and the distinction between old growth and secondary, early-successional vegetation. The functional traits of species in open ecosystems can be highly informative as to the dominant consumers maintaining their structure. Traits adapted to different fire regimes and those adapted to vertebrate herbivory are considered and compared. Faunal differences between open and closed vegetation are beginning to emerge from both invertebrate and vertebrate studies and indicate the importance of vegetation structure for habitat choice.

The forgotten habitats in conservation: early successional vegetation

Conservation efforts in terrestrial environments have focused on preserving patches of natural habitats and restoring disturbed habitats, with the main goal of transforming them into forests or habitats that resemble the original conditions. This approach tends to overlook the importance of conserving early successional vegetation (e.g., riverside vegetation, natural regeneration, young secondary forests), which often includes a large number of species (e.g., plants and animals) associated with or restricted to these habitats. In this paper we want to bring to attention the importance of preserving early successional vegetation, and to encourage scientists to investigate, e.g., the diversity, distribution, and species interactions occurring in these habitats. To address these goals, we focus on two main objectives: (1) to identify the common types of early successional vegetation in the Costa Rican Central Valley; and (2) to use some case studies to draw attention to the importance that such areas have as reservoirs of a large portion of the diversity unique to early successional stages. We first include an example to show the diversity of plants in small forest patches immersed in a large urbanized area. We provide general information on the insects that occur in early successional vegetation in urban areas, and in further detail examples of butterflies. Additionally, we provide examples of birds and mammals that are restricted to early successional vegetation, and how the reduction of this vegetation type affects species conservation. Finally, we encourage scientists to investigate these early successional habitats, particularly those species exclusive to early successional stages. Special attention should be paid to endemic species and those with a restricted distribution. Information of this type will make conservation of the diversity contained in these habitats possible.