Bird Species Density Research Articles

A conservation assessment of birds in the Karoo region of South Africa: densities, populations, ranges, and trend estimates

The Karoo region of South Africa, which includes the Succulent and Nama Karoo biomes, supports a unique avian fauna, with ten bird species occurring exclusively in this arid-zone region and many others exhibiting a strong preference for this habitat. To better determine the conservation status of these birds, we conducted point counts to estimate population densities of bird species occurring in the South African Karoo region in 2017 and 2018. We also used data of the South African Bird Atlas Projects (SABAP2) to estimate the species’ ranges and to determine population trends. Although the population densities are naturally low for most species, their ranges are very large, and reporting-rate trends appear stable for most species. Our analysis reveals that none of the Karoo bird species are currently of serious conservation concern. However, the Red Lark Calendulauda burra and Sclater’s Lark Spizocorys sclateri should be considered regionally Near Threatened as they are habitat specialists with inferred declining populations and are not currently protected within any designated conservation areas. Given the rapid transformation of landscapes linked to mining and alternative energy developments currently underway in the Karoo, combined with the poor representation of bird species in protected areas, it is imperative that special attention be paid to the conservation of bird species endemic to the Karoo, and that appropriate mitigation measures be taken by developers.

A dataset of bird checklist and community characteristics during breeding and wintering seasons in typical forest ecosystems of Dinghushan (2015–2018)

Bird diversity and its community structure are important indicators for the long-term monitoring of biodiversity in ecosystems. Three typical forest vegetation types have been well preserved in Dinghushan National Nature Reserve, including the monsoon evergreen broad-leaved forest, the mixed Pinus massoniana/broad-leaved forest and the Pinus massoniana coniferous forest. In particularly, the monsoon evergreen broad-leaved forest has a conservation history of more than 400 years without any human disturbance. The dataset consists of organized data on the long-term monitoring of bird communities during breeding and wintering seasons from 2015 to 2018 in all three forest types. Field surveys recorded information such as bird species, number, time, distance, ground height, habitat type, activity substrate and behavior. Moreover, we carried out various data analyses of diversity index, evenness index, dominance index, similarity coefficient of bird community and occurrence frequency, individual number, as well as average density of bird species in different survey periods. The dataset includes a total of 89 species from 9 orders and 35 families. This dataset provides valuable information for future studies on bird communities, and for better understanding inter-species interaction between multiple groups of plants and animals. It is further expected to support the protection and management of forest ecosystems in this region.

Effects of forest management on the conservation of bird communities in eastern North America: A meta‐analysis

AbstractForest management affects conditions for both early‐ and late‐seral organisms, and managers and conservationists require information for balancing the ostensibly opposing habitat needs of both these guilds. We conducted meta‐analyses that examined silvicultural systems with a range of postharvest retention and their impacts on mature‐forest and shrubland bird species densities in eastern North America during the breeding season. Densities of mature‐forest bird species generally declined as canopy tree retention and basal area decreased, although some mature‐forest species had similar densities among unharvested and partially harvested (e.g., first‐entry shelterwood) stands, and others had their highest densities in shelterwoods. We conducted a previous meta‐analysis study, which showed most shrubland bird species in the region increase with harvest intensity, but some shrubland species had similar densities in clearcuts and shelterwoods. Given the contrasting effects of harvest intensity on the two avian guilds, we used Partners‐in‐Flight conservation values to generate objective community‐wide conservation indices relative to postharvest tree retention. Clearcuts and shelterwoods typically had the highest conservation values, and unharvested and lightly thinned stands (70%–100% tree retention) had the lowest conservation scores. Many declining shrubland bird species of conservation concern are abundant in low‐retention stands, thus elevating the conservation value of these stands. Additionally, high conservation values of harvested stands with 40%–70% tree retention represent the presence of both shrubland and mature‐forest species; the latter are potentially responding to enhanced understory structure needed for avian nesting or foraging. In contrast, contemporary closed‐canopy forests in eastern North America are generally characterized by low structural diversity and are mid‐seral stands due to historical patterns of land use and tree harvesting. Although avian community conservation values were lowest in high‐retention stands and many other threatened, non‐avian taxa depend on open‐canopy, managed forests, managers should note that late‐seral, unharvested stands can provide important habitat for old‐growth‐dependent taxa and any intensive forestry should also take into account other factors. Considering the growing interest in using postharvest retention of canopy trees to meet ecological objectives, our novel synthesis can assist managers in assessing species‐specific and community‐wide avian responses to tree retention levels along the entire gradient of canopy treatments.

Does the use of exotic and native tree species in rehabilitation attract birds equally? The case of Golden Pride Gold Mine, Tanzania

AbstractIn mining areas, habitat rehabilitation is increasingly being used to minimise biodiversity loss and restore areas of natural habitat. In some mining areas, both exotic and native tree species are used in rehabilitation. For the most part, the effectiveness of using both native and exotic plant species in rehabilitation to attract avifauna is not known. Using a fixed‐radius point‐count method to sample birds, this study assessed the extent to which sites rehabilitated with exotic plant species attracted local avifauna compared to sites rehabilitated with native plant species, as well as to the unaffected surrounding woodlands. Rehabilitation dominated by exotic species had a lower density of bird species and individuals, lower relative abundance and lower species diversity compared with sites rehabilitated by native plant species and the surrounding woodlands. The results suggest that the use of exotic plant species, L. leucocephala, should be avoided in rehabilitation. Therefore, for restoration purposes it is desirable to use native tree species in rehabilitation rather than exotic tree species.

Diversity and population density of birds at the Jahangirnagar University campus, Bangladesh

Rapid urbanization is changing the habitats of many wildlife species. Even so, certain species appear to adapt and now have thriving populations within cities. To look at the capacity for these spaces to provide “habitat” we examined population density of bird species using Jahangirnagar University campus close to the Dhaka mega city, Bangladesh. Four strip transects were surveyed from March 2008 to February 2009 (12 times/transect). A total of 101 species were found along the transect areas. The density of Lesser Whistling Duck (Dendrocygna javanica) was the highest 107.02indiv. /ha while Large-tailed Nightjar (Caprimulgus macrurus) was the lowest 0.01indiv. /ha among resident birds of Jahangirnagar University campus. Among the migratory birds, the density of Pintail Snipe (Gallinago stenura) and Common Stonechat (Saxicola torquata) were the highest (1.99indiv. /ha.) and the lowest (0.02indiv. /ha.), of the different available habitats, water bodies contained the highest density (318.59indiv. /ha) and grassland contained the lowest (2.48indiv./ha) of bird population. The percentage of average density of non-passerine and passerine birds was 65% and 35%, respectively. Future studies of avian composition and density is recommended at a regular interval to understand changes in the carrying capacity and avian community of the campus as a function of altering habitat due urbanization.
 Bangladesh J. Zool. 48(2): 289-300, 2020

Avian Community Density and Distribution Patterns among Nicaraguan Conventional and Organic Shade-Coffee Plantations

We used a distance-sampling survey method and multivariate statistics to obtain a unique estimate of bird species density and seasonal variation in shade-coffee plantations. Our aim was to determine which cultivation practices among plantations contribute most to bird abundance. We conducted avian species counts at 200 points distributed across 10 shade-coffee plantations bordering the lower slopes of the Mombacho Volcano Natural Reserve, in western Nicaragua. We measured vegetation structure (coffee plants and overstory). We used principal components analysis (PCA) among 14 habitat variables to derive a single phyto-geoclimate summary measure (PGSM). We also used PCA to derive an avian abundance summary measure (AASM) from three bird survey variables, which proved to be a good predictor of bird density. We found higher bird species densities (AASM) in organic and traditional polyculture shade coffee plantations whose structurally complex and diverse overstory could be verified by PGSM. However, this finding was true only for birds that were habitat specialists. Our results provide further evidence for promoting organic coffee cultivation practices that maintain a structurally diverse overstory and help retain avian species richness and abundance in coffee plantations.

Anthropogenic activity expressed as ‘artificial light at night’ improves predictive density distribution in bird populations

Artificial Light At Night (ALAN) is one of the most important anthropogenic environmental components that affects biodiversity worldwide. Despite extensive knowledge on ALAN, being a measure of human activity that directly impacts numerous aspects of animal behaviour, such as orientation and distribution, little is known about its effects on density distribution on a large spatial scale. That is why we decided to explore by means of the Species Distribution Modelling approach (SDM) how ALAN as one of 33 predictors determines farmland and forest bird species densities. In order to safeguard study results from any inconsistency caused by the chosen method, we used two approaches, i.e. the Generalised Additive Model (GAM) and the Random Forest (RF). Within each approach, we developed two models for two bird species, the Black woodpecker and the European stonechat: the first with ALAN, and the second without ALAN as an additional predictor. Having used out-of-bag procedures in the RF approach, information-theoretic criteria for the GAM, and evaluation models based on an independent dataset, we demonstrated that models with ALAN had higher predictive density power than models without it. The Black woodpecker definitely and linearly avoids anthropogenic activity, defined by the level of artificial light, while the European stonechat tolerates human activity to some degree, especially in farmland habitats. What is more, a heuristic analysis of predictive maps based on models without ALAN shows that both species reach high densities in regions where they are deemed rare. Hence, the study proves that urbanisation processes, which can be reflected by ALAN, are among key predictors necessary for developing Species Density Distribution Models for both farmland and forest bird species.

Response of shrubland birds to regenerating clearcut area and shape

ABSTRACTConservation of birds that breed in early‐successional forests will require an understanding of their response to patch size and shape during the early seral stages following disturbance. We modeled the effects of patch area, patch shape, and time period following harvest on territory densities of 5 shrubland bird species and bird community composition in 36 clearcuts from 1997 to 2014 in the Missouri Ozarks, USA. Our best‐supported models indicated that densities of indigo bunting (Passerina cyanea), yellow‐breasted chat (Icteria virens), and prairie warbler (Setophaga discolor) declined from the early time period (1–7 years post‐harvest) to the late time period (12–18 years post‐harvest), regardless of clearcut area or shape. Yellow‐breasted chat density and bird species richness were positively related to clearcut shape complexity. Bird species richness increased, and bird species density decreased with clearcut area during both time periods. Non‐metric multidimensional scaling indicated that bird community composition was strongly related to time since harvest. Within the spatial scale of our study, successional stage is more influential than clearcut size and shape, and some bird species may benefit from relatively small or irregularly shaped clearcuts. © 2019 The Wildlife Society.

Effects of habitat type and intensity of use on the breeding birds of gravel pits in Poland

Natural sands and gravels have been a basic raw material for building ever since the dawn of civilisation. Even though the natural environment is transformed and may be degraded by gravel pits, these areas create wholly new conditions for the development of interesting assemblages of avifauna. This study was conducted in 2013–2016 in 64 gravel pits in east-central Poland. We examined whether gravel excavation led to the formation of habitats that support an avian community. We identified key factors affecting the richness, diversity and density of bird species, on the basis of which we were able to recommend practical conservation measures. The richness of species and their density were positively affected by the intensity of gravel pit exploitation: of prime importance were the extensively utilised gravel pits. The fewest species and the lowest density of birds were recorded in the most intensively exploited gravel pits, where the large sandy areas are an attractive breeding habitat for just a few species. The presence of emergent vegetation was found to be the most important factor influencing species richness and species diversity. This is the first comprehensive study to demonstrate the great value of gravel pits for breeding birds. We recommend that recultivation of these areas should aim at retaining the habitats of the most valuable bird species that utilised the gravel pit while it was operative. One-directional recultivation, be it the creation of woodland, farmland or a water body, should be avoided at all costs, because most of the bird species using the area before recultivation will abandon a homogeneous habitat. Another important task is to maintain or enable the existence of emergent vegetation around water bodies, as this has a considerable influence on birds.

A Symphony of Poems and Pictures: Hwa-Jen Ho's Nonfiction Picturebooks about Wild Birds in Taiwan

A Symphony of Poems and PicturesHwa-Jen Ho's Nonfiction Picturebooks about Wild Birds in Taiwan Yi-Ching Su (bio) Immersing himself in birdwatching in Taiwan—a small island country that has the second highest bird species density in the world—for over thirty years, Hwa-Jen Ho dedicated his life to wild bird ecology and conservation. Using poetic words and pictures, Ho creates nonfiction picturebooks to illuminate wild bird ecology and to reveal the wonders of nature. This article focuses on Hwa-Jen Ho's life and his five nonfiction picturebooks about wild birds in Taiwan. Inspired by Roger Tory Peterson, a twentieth century American ornithologist who published the first modern field guide to birds, Hwa-Jen Ho devoted his life to wild bird ecology and conservation. As a dedicated artist, writer, and ornithologist, Hwa-Jen Ho shares the wonders of birds with young readers through his words and artwork. Before creating nonfiction picturebooks about birds for children, Ho was an art editor for China Times. While he was working in the newspaper industry, Ho was invited to create a double-page spread illustration of the Swinhoe's pheasant for a publication. After seeing Ho's illustration of Swinhoe's pheasants wandering in a vast grassland, several bird experts expressed that they had never seen a Swinhoe's pheasant wandering recklessly in an open field, for it is shy and alert, and it is usually found in the mountains of central Taiwan. The experts' comment made Ho feel the urge to devote himself to studying Taiwan's endemic bird species (Ho, "Ho, Hwa-Jen: Wild Birds Observation, Woodcuts, Picturebooks"). Click for larger view View full resolution Ho resigned from China Times in 1986 and went to Liugui Forestry Research Center to study birds in southern Taiwan. There, Ho walked ten kilometers everyday on the same mountain path to document the birds' life for ten months. Using the data he collected in Liugui, Ho published 台灣野鳥圖誌 (Field Guide to the Wild Birds in Taiwan) (see Fig. 1), a bird-identification guide centering on the wild birds living in the medium altitude mountains in Taiwan. As a self-taught woodcut artist, Ho experimented with different wood blocks, lines, colors, and carving techniques to make the birds come alive on the pages in this field guide (Chen 20). Wanting to pass down his bird watching experience, Ho accepted a publisher's invitation to create nonfiction picture-books about birds in Taiwan for children. 鳥兒的家 (The Homes of the Birds) is about birds' homes in the Lanyang Plain, an ecologically diverse place in northeastern Taiwan. To engage young readers [End Page 84] in guessing where the birds' homes are, Ho uses the question-and-answer approach. The content also starts from introducing the birds children are familiar with, such as the striated swallows, to the ones that are less known, such as the little ringed plovers. The back endpaper presents the whole scene of the introduced birds and their homes in the Lanyang Plain (see Fig. 2). This book gives children a sense of place, and it naturally invites readers to go out and discover birds' homes. Click for larger view View full resolution 彩鷸奶爸 (Painted-Snipe Daddy) is written from a baby painted-snipe's point of view. Ho tells the everyday moments painted-snipe daddy spent with his babies in the Lanyang Plain in dialogue between father and children. Woodcut is used as the medium of the book illustration. The lines powerfully show the painted-snipe daddy spreading his wings to protect his babies (see Fig. 3). They also reveal the painted-snipe daddy's tenderness and patience while feeding his babies (see Fig. 4) and waiting for them to climb over a mound one by one (see Fig. 5). Through dialogues and woodcuts, Ho reveals the ecology of painted-snipes to young readers. 台灣鳥四季 (The Four Seasons of the Birds in Taiwan) is a book of haiku poems about Taiwan's endemic birds species in the four seasons. When introducing the Taiwan bush warbler, Ho writes, Under the haiku poem, Ho provides further explanation: "In autumn, the giant knotweeds are like having wings and flying everywhere. The Taiwan bush warbler's song resembles...

Are Landscape Configuration Metrics Worth Including When Predicting Specialist and Generalist Bird Species Density? A Case of the Generalised Additive Model Approach

Due to the complexity of factors that influence species density on a large geographical scale, the effectiveness of the species distribution model (SDM) is still debatable. That is why the buffer zone (the area within 100 m from the outside edge of the patch), the core, i.e. (patches excluding the 100 m buffer zone from the patch’s edge) and patch shape are explored in this study to see how they affect the density of habitat specialist and generalist bird species. Two sets of generalised additive models were generated separately for each of the four bird species: One set of models contained landscape configuration metrics as an additional predictor variable, and the other did not. The results showed that models including the core, the buffer zone and the shape of patches turned out to be definitely better than models without them. Specialist species, the Corn bunting and the Wood nuthatch, are more likely to occur in the core of the preferred patches, and they choose those of a simple shape; while generalist species, the Whinchat and the Tree pipit, are more probable to be present in the buffer zone of a more complicated shape. Thus, the results clearly show that specific landscape configuration models can improve the predictive power of SDMs and can be used as an effective tool for predicting species density and functional bird diversity (specialist and generalist). Furthermore, from the applied ecology perspective, detailed landscape configuration metrics can be considered as a surrogate of elusive habitat conditions.

Should topographic metrics be considered when predicting species density of birds on a large geographical scale? A case of Random Forest approach

Species Distribution Modelling (SDM) is a group of statistical tools that describe species distribution in environmental gradients in order to create their predictive distribution. However, due to the complexity of factors that influence the occurrence or density of species these methods’ effectiveness is still debatable. That is why we decided to explore how topographic metrics, such as altitude, slope, roughness and aspect, would affect the density of farmland (Icterine warbler) and forest (Eurasian golden oriole) bird species. We generated two sets of SDMs for each of the two bird species: One set of models contained topographic metrics as a predictor variable, and the other did not. Out-of-back procedures in the Random Forest approach and evaluation models based on independent dataset scores showed that omitting topographic metrics as predictors resulted in a substantial reduction of model performance for both lowland and upland bird species. Further analysis of predictive maps revealed that neglecting topographic metrics resulted in large over-predictions of species’ densities in regions where these species were rare. Importantly, our results also support the notion that detailed topographic metrics can be considered as a surrogate for elusive climatic factors and the habitat’s condition. Hence, the study emphasises that the process of selecting predictor variables, especially topographic metrics, is one of key elements in developing Species Distribution Models for birds, even for those species which are not directly dependant on the topographic metrics.

Tree and bird functional groups as indicators of recovery of regenerating subtropical coastal dune forests

AbstractFunctional diversity indicators are increasingly used to monitor forest function recovery because they connect biodiversity to ecosystem functions. However, identifying which functions deviate from a reference forest has not received much attention, despite its potential to inform restoration interventions. In this study, we used functional groups to assess the recovery of ecosystem functions in regenerating coastal dune forests. We surveyed birds and trees in forest of different ages and a reference old‐growth forest in KwaZulu‐Natal, South Africa. We classified species into functional groups for each taxa based on functional traits or a priori defined categories (i.e. guilds) and quantified the number of species within functional groups as a proxy of function stability. Bird species density followed an asymptotic trajectory, reaching old‐growth forest values after 25 years. Insectivores and granivores showed saturating trajectories, whereas small frugivores and generalists increased linearly. With the exception of large frugivores, relative abundances of bird functional groups progressed towards old‐growth forest values as the forest aged. Tree species density increased linearly with forest age. In contrast to old‐growth forests, large‐canopy trees and understory shrubs were under‐represented, while mid‐canopy trees dominated regenerating forests. Our result suggests that most bird, but not tree, functions may have been restored. The trend in large frugivore numbers may warrant further investigation, as their low numbers may have hampered the recovery of tree functions. We conclude that functional group trajectories can track functions that deviate from a benchmark, and may therefore direct adaptive actions to recover the stability of regenerating forest.

Multi-scale responses of breeding birds to experimental forest management in Indiana, USA

Forest managers frequently must balance timber production and wildlife conservation goals when choosing management approaches. We studied the response of the breeding bird community to silvicultural treatments at multiple spatial scales over a 10-year period in 60–90year old oak-hickory forests of Indiana, USA. We conducted point count surveys in a 3603-ha study area both before (n=3years) and after (n=6years) application of silvicultural treatments. Bird responses were analyzed at two spatial scales: management units and individual harvests. At the multi-stand management unit scale, treatments were even-aged management, uneven-aged management, and a no-harvest control. We also analyzed the responses of birds at the spatial scale of individual timber harvests (clearcuts, patch cuts, shelterwood harvests, and single-tree selection). Multi-species N-mixture models were used to estimate bird species density and richness at both spatial scales. At the management unit scale, 4 species increased in density following even-aged management (relative to the control), while 1 species (Red-eyed Vireo [Vireo olivaceus]) declined. A larger number of species responded both positively (n=9) and negatively (n=3) to uneven-aged management. Overall richness was significantly greater in the even- and uneven-aged treatments than in the control. At the harvest scale, only the clearcuts and patch cuts resulted in changes in the density of any species, but a larger number of species were impacted and effect sizes were generally larger in these harvests than at the management unit scale. In the clearcuts, 13 species increased in density relative to the no-harvest control, while 5 species declined. A larger number of species were impacted by patch cut harvests (18 species increasing and 6 decreasing). Overall richness was greatest in the clearcut harvests. At both scales, species that increased were generally those associated with early successional habitat, including the Eastern Towhee (Pipilo erythrophthalmus) and Indigo Bunting (Passerina cyanea), while species that declined were typically associated with mature forest habitat (e.g., Red-eyed Vireo [Vireo olivaceus] and Ovenbird [Seiurus aurocapilla]). Harvesting appeared to benefit several species of conservation concern in Indiana, including the Cerulean Warbler (Setophaga cerulea) and Black-and-white Warbler (Mniotilta varia). Both management treatments appear to be good options for simultaneously conserving bird species diversity (particularly of early-successional specialist species) while meeting other forest management goals. However, the impact of the next phases of the shelterwood harvests remains to be evaluated.

Birdwatching tourism infrastructure planning in the Ria Formosa Natural Park (Portugal)

We investigated the Ria Formosa Natural Park located in the lagoon of the same name; it is famous for a great diversity of bird species and offers outstanding possibilities for the development of a special type of ecological tourism, birdwatching, that attracts birdwatchers from across the globe. It is shown that the existing natural resources on this territory should be complemented by an appropriate infrastructure and the rules in order to ensure tourism sustainability and development in connection with a high ecological significance of the territory and a heavy demand from visitors. Using landscape approach and methods of geoinformationbased landscape-interpretation mapping, extrapolating the density of different bird species, calculating integral indicators for assessing ornithological resources as well as infrastructure development techniques, we undertook a planning procedure of the birdwatching tourism infrastructure, including trails and observation points. As initial data, we used vegetation and soil maps, topographic maps, space images, data on the density of bird species in different biotopes, and field investigations. We generated the population density maps for each bird species as well as the biotope assessment map for all bird species, based on calculating the sum of the products of densities of each species by the ecological value of the species. Also, the landscape map was used to develop the territorial zoning map, having regard to the possibilities and limitations of constructing trails of different classes. Using spatial cross-matching of the assessment maps for ornithological resources and the trail zoning map, we identified places holding promise for the construction of the birdwatching tourism infrastructure. It is shown that the suggested method provides a means of making a proximate assessment of the territory from different perspectives, based on knowledge of a territory’s landscape structure; it is a prompt and inexpensive technique as contrasted to field investigations of the entire territory; however, it calls for further detailed investigation into promising areas.

Implications of afforestation for bird communities: the importance of preceding land-use type

Afforestation of open habitats is one of the principal land-use changes underway in Europe and elsewhere in the world at present, and it can have a considerable impact on local biodiversity. The sustainable expansion of global forest plantations requires an understanding of the factors that determine the ecological impacts of afforestation. This study set out to determine the importance of preceding land-use type in determining the outcomes of afforestation for bird communities. Paired comparisons of 5-year-old exotic conifer plantations and matching non-forested sites were studied in areas of low (peatland), intermediate (wet grassland) and high (improved grassland) management intensity. Afforestation resulted in an overall increase in total bird density in all three habitat types. The effects of forest planting on bird conservation were found to be positively related to prior management intensity at the site. The density of bird species of conservation concern increased in response to the planting of intensively managed grassland sites, but decreased in response to afforestation of peatlands and of grasslands under intermediate management intensity. This study shows that plantation forests can, in some contexts, offer opportunities for bird conservation, and the findings highlight the trade-offs that are an integral part of land-use change. Therefore, where afforestation planning includes consideration of its impact on bird communities, planting should take place predominantly on sites of low biodiversity value, such as agriculturally improved grasslands. Furthermore, the preservation of sites of high conservation value within areas of afforestation would confer advantages on bird communities.

Natural regeneration determines wintering bird presence in wind-damaged coniferous forest stands independent of postdisturbance logging

Natural disturbances in European production forests are undesired from an economic perspective but are important drivers of biodiversity. The removal of damaged timber to restore economic value is accompanied by negative effects on various species groups, particularly breeding bird communities, and can hinder natural regeneration. However, little is known about the effect of postdisturbance logging on bird assemblages in winter when temperatures are low and food resources are unpredictable. We conducted fixed-radius point counts of wintering birds in forest stands logged or unlogged after windthrows and in mature forest stands to test our predictions that bird species densities and abundances (i) are lower in postdisturbance logged stands and (ii) depend on the amount of natural regeneration, (iii) which differs between logged and unlogged stands. Our generalized linear mixed model did not support the expected differences in bird abundance or species densities between postdisturbance logged and unlogged stands but indicated that mature forest stands harbor the highest bird abundances and species densities. The number of regenerated coniferous trees significantly positively affected wintering bird abundances in both postdisturbance logged and unlogged stands. Hence, the number of coniferous trees appears to be a main predictor of wintering bird presence.

Fire severity affects mixed broadleaf–conifer forest bird communities: Results for 9 years following fire

ABSTRACT Wildfire is an important disturbance regime that can structure wildlife communities and their habitats for many years. Using a before-after-control-impact framework, we evaluated the effect of the Quartz Fire on a mixed broadleaf–conifer forest and associated bird community in southwestern Oregon, USA, over 10 yr. To assess whether fire severity explained changes better than simply whether an area was burned, we used a tiered sampling approach by comparing unburned control points with either all burned points combined (burned) or those same points partitioned by severity level (low, moderate, high). As expected, overall tree cover decreased while cover of shrubs increased in response to greater fire severity. This pattern was most pronounced in high-severity areas, where tree cover declined by 40% and remained depressed, but shrub cover recovered from 10% the year following fire to 75% by year 6. Ordinations of bird species density showed turnover in community composition in all burned areas comb...

Bird Diversity of Dekinda Forest Reserve, Balana, Sri Lanka: Implications for Conservation

Dekinda Forest Reserve, located close to the historic town of Balana,Sri Lanka (7°16’N, 80°29’E, 525-585m above sea level) consists of rainforest plant species spanning an area of about 40 ha. The forest has been maintained since the colonial times as a watershed reserve for nearby plantations, most of which comprised tea and paddy. The objective of the present study was to measure the avifaunal diversity in Dekinda Forest Reserve, as an indicator of its overall biodiversity, and compare it with those of nearby home gardens. The study was conducted from March to June, 2012. Point counts with unlimited distance were used in conjunction with Distance© software (Release 6) to document the abundance and density of bird species. Peak counting hours were between 0600-0900 h and 1600-1830 h. Counts were made weekly. Despite its small size, the forest reserve is home to 58 bird species. Among the notable species, therewere six endemic species, namely, the Sri Lanka wood pigeon (Columba torringtoni) (estimated density 8/km2), Layard’s parakeet (Psittacula calthorpae) (19/km2), Sri Lanka lorikeet (Loriculus beryllinus) (70/km2), yellow-fronted barbet (Megalaima flavifrons) (79/km2), Sri Lanka scimitar babbler (Pomatorhinus melanurus) (11/km2), and brown-capped babbler (Pellorneum fuscocapillus) (10/km2). In addition, four proposed endemic species were also recorded. Given the importance of this forest as a watershed area and the large number of bird species it supports, Dekinda Forest Reserve is clearly an important site for biodiversity conservation. DOI: http://dx.doi.org/10.4038/cjsbs.v43i1.7283 Ceylon Journal of Science (Bio. Sci.) 43(1): 137-146, 2014

Isolation, patch size and matrix effects on bird assemblages in forest reserves

Habitat fragmentation is one of the most studied topics in ecology but our knowledge is still limited particularly concerning matrix effects on species distribution in a human-dominated landscape. We tested the ability of random sampling hypothesis, colonization–extinction dynamics and matrix-related concepts to explain the variation in species richness, total bird density and community composition in old-forest bird assemblages in two contrasting landscapes. We collected data on breeding bird abundances from 66 old-growth forest reserves in NE Finland and six larger areas in adjacent Russian Karelia using the line transect method. In Finland, protected old-forest patches are embedded in a matrix dominated by young regeneration stands. In Russia, study areas were situated in continuous, old forest dominated landscapes. Bird assemblages in old-forest patches embedded in human-modified matrix in Finland were not random samples from Russian bird assemblages. In the Finnish assemblages, species richness was lower and total bird density higher. Species richness declined with increasing distance (isolation) to Russia. Bird assemblages in large forest reserves in Finland close to Russia were structurally more similar to assemblages in the continuous reference landscape than those in small and more distant reserves. The results support the idea that several mechanisms related to colonisation–extinction dynamics and to matrix resource availability influence species distribution in fragmented landscapes but in species-specific ways. We conclude that even though small and isolated protected areas may foster high relative bird species density their ecological integrity is compromised, and therefore, improving matrix quality around reserves may lead to considerable conservation benefits.