Species Richness Of Bird Communities Research Articles

Optimizing tropical forest bird surveys using passive acoustic monitoring and high temporal resolution sampling

AbstractEstimation of avian biodiversity is a cornerstone measure of ecosystem condition. Surveys conducted using autonomous recorders are often more efficient at estimating diversity than traditional point‐count surveys. However, there is limited research into the optimal temporal resolution for sampling—the trade‐off between the number of samples and sample duration when sampling a survey window with a fixed survey effort—despite autonomous recorders allowing easy repeat sampling compared to traditional survey methods. We assess whether the additional temporal coverage from high temporal resolution (HTR) sampling, consisting of 240 15‐s samples spread randomly across a survey window detects higher alpha and gamma diversity than low temporal resolution (LTR) sampling of four 15‐min samples at the same locations. We do so using an acoustic dataset collected from 29 locations in a region of very high avian biodiversity—the eastern Brazilian Amazon. We find HTR sampling outperforms LTR sampling in every metric considered, with HTR sampling predicted to detect approximately 50% higher alpha diversity, and 10% higher gamma diversity. This effect is primarily driven by increased coverage of variation in detectability across the morning, with the earliest period containing a distinct community that is often under sampled using LTR sampling. LTR sampling produced almost four times as many false absences for species presence. Additionally, LTR sampling incorrectly found 70 species (34%) at only a single forest type when they were in fact present in multiple forest types, while the use of HTR sampling reduced this to just two species (0.9%). When considering multiple independent detections of species, HTR sampling detected three times more uncommon species than LTR sampling. We conclude that high temporal resolution sampling of passive‐acoustic monitoring‐based surveys should be considered the primary method for estimating the species richness of bird communities in tropical forests.

Time turnover of species in bird communities: the role of landscape diversity and climate change

The challenge of searching for patterns of species turnover dynamics in communities of living organisms is directly related to solving problems of stability and functioning of ecosystems. Avian communities are an essential structural and functional component of terrestrial and aquatic ecosystems which are highly diverse and play an important role in a wide range of ecosystem functions. The issue of changes in the dynamics of amphibiotic landscape complexes, where terrestrial and aquatic ecosystems conjugate, is practically not solved. In this connection, a study was carried out within a landscape system, which presents terrestrial and aquatic ecosystems that were in different degrees of anthropogenic transformation. The dynamics of bird communities was considered in the context of recent global climate change. The investigation was conducted in the landscapes of the south and south-east of Ukraine in the nesting seasons 1988–2018. Within the landscape system associated with the Molochny estuary, the ten most important types of ecosystems were distinguished, which included : agricultural lands, artificial forest belts, meadows, islands and spits, reed beds, urban areas, solonchaks, steppe, cliffs, artificial forests. The temporal turnover of the bird communities was decomposed into two parts: the first term (D1) related to the amount of change in community composition, and the second term (D2) being dependent only on the amount of change in community size sensu its abundance. The contribution ratio of the species and of the environment variable were calculated to identify drivers that influence the turnover measure. The average annual temperature and the sum of annual temperatures were considered as environment variables. The bird metacommunity of the studied landscape system was represented by 132 species from 86 genera, 42 families and 13 orders. During the research period the average annual temperature varied from 9.5 to 12.5 ˚C. and the temperature dynamics were subject to the linear trend. An oscillatory component was also present in the temperature dynamics. The annual rainfall ranged 220–761 mm. A coherent change in precipitation and temperature was observed in the period until 2011. After that, the temperature growth stabilized and the amount of precipitation began to fall sharply. The steppe bird community was represented by an extremely small number of species, but demonstrated the ability to maintain a stable structure for a long time. The main fluctuations of the community were quantitative changes in abundance, while the turnover of species was practically absent. Species of the community replace each other cyclically, but there were no targeted changes in community structure. Temperature and precipitation were the main drivers of the bird community in the steppe. The bird communities on salt marshes were characterized by a stable abundance, but a constant directed turnover of species. Reduced water levels and the disappearance of islands in the salt marshes increased the risk of threats from predators, which could lead to a decrease in the abundance of some species. The islands and spits were characterized by high species turnover with quasi-cyclical population dynamics. The main feature of the community dynamics was a decrease in the role of precipitation and an increase in the role of the time factor. The role of temperature remained stably low. The species richness of bird communities in agrarian lands was higher than in steppe communities. The turnover measure was significant because of the increased abundance of Alauda arvensis. Over time, the role of precipitation in the community dynamics has been decreasing and the role of time has been increasing. The value of temperature varied, but was at a stationary level. The turnover of species was compensated by an increase in the abundance of bird communities. The obtained results are in line with findings indicating that despite more stable land use intensities in recent years, climate change has not overtaken land use intensities as the main driver of bird population dynamics.

A baseline survey of birds in native vegetation on cotton farms in inland eastern Australia

Context The Australian cotton industry has committed to (1) understanding the biodiversity value of remnant native vegetation on cotton farms, (2) funding independent, evidence-based assessments of the industry’s sustainability and environmental performance, and (3) investing in research that reports against recognised sustainability indicators. Aims The present study reports the results of an industry-wide survey to benchmark bird diversity in native vegetation on cotton farms spanning a 1260-km north–south subcontinental gradient from Central Queensland (Qld) to Southern New South Wales (NSW). Methods Between September and November 2014, birds were sampled twice on separate days in 2-ha quadrats (20 min per census) in eight remnant vegetation types as well as in native revegetation at 197 sites on 60 cotton farms spread across the principal cotton-growing zones (Central Qld, Border Rivers, Macquarie and Southern NSW) in inland eastern Australia. Key results We recorded 185 bird species in remnant and planted native vegetation on cotton farms. Species richness of bird communities declined from north to south. Bird community composition was similar in the three southern zones, differing somewhat in the north. The most frequent species were large (>60 g), readily detected landbirds common in agricultural districts, but 26 of the 53 extant species of conservation concern in the study region were also recorded, including 16 species of declining woodland birds. Bird composition, abundance, richness and diversity differed among the nine native vegetation types, with maximal and minimal bird abundance and diversity metrics recorded in river red gum-dominated riparian vegetation and grassland respectively. Conclusions Each remnant vegetation community had a generally distinct bird assemblage, indicating that all vegetation types contribute to regional biodiversity in cotton-growing zones in inland eastern Australia. Appropriate on-farm management of all remnant and planted native vegetation will assist regional biodiversity conservation. Implications For the Australian cotton industry to meet its stated environmental responsibilities, growers should be encouraged to prioritise the conservation management of remnant, riparian and planted native vegetation on cotton farms and the monitoring of bird species as an indicator of regional biodiversity response.

Assessing the landscape-dependent restoration potential of abandoned farmland using a hierarchical model of bird communities

Expansion and intensification of agriculture have led to an immense decrease in biodiversity. However, the area of abandoned farmland has been increasing globally in recent years and is expected to provide novel habitats for various organisms. Despite the promising potential for biodiversity conservation in agricultural landscapes, few studies have compared biodiversity among multiple land use types, including abandoned farmland. We examined the effects of major land use types (wetland, grassland, forest, farmland, abandoned farmland) and the surrounding landscape openness (proportion of wetland/grassland in the surrounding area) on the abundance and species richness of bird communities and four functional groups (wetland, grassland, farmland, and forest species) in the agricultural landscape of central Hokkaido in northern Japan. The abundance of wetland/grassland species in abandoned farmland tended to be intermediate between those of their original habitats (wetland and grassland) and other land uses (forest and farmland), and to be positively associated with the landscape openness. The abundance of forest species tended to be higher in forest areas than in areas with other land use types and was not associated with the landscape openness. The abundance and species richness of the bird community were predicted to be high in large abandoned farmland areas surrounded by open land. For wetland species, whereas total abundance was predicted to be primarily mediated by landscape openness, species richness was predicted to be primarily mediated by the farmland abandonment area. The abandoned farmland in our study area would not currently have a high conservation value for forest birds. However, the abandonment of farmland surrounded by open land would significantly improve the conservation of wetland/grassland birds in the agricultural landscape. Given the decline in the area of grassland, wetland, and low-intensity farmland, farmland abandonment provides an opportunity to conserve and restore the declining populations of wetland and grassland birds.

Seasonal Incidence and Diversity Pattern of Avian Communities in the Bangalore University Campus, India

The present study deals with the species abundance, diversity and species richness of avian communities in the Bangalore University Campus (BUC), Bengaluru, India. One hundred and six species of birds belonging to 42 families under 68 genera were recorded. Shannon–Wiener’s and Fisher’s alpha diversities, species evenness, species richness of bird communities, number of bird species and percentage of population density of birds between various seasons in the BUC differed significantly between the study years. Of these bird species, the relative abundance (6.96 %) and species distribution ratio (0.070) of Psittacula krameri were highest, whereas relative abundance (0.04 %) and species distribution ratio (0.002) of Coracias benghalensis were lowest. The existing 32 species of flowering plants/trees belonging to 29 genera under 14 families in the campus are used for perching by birds. Moreover 29 species of flowering plants/trees belonging to 24 genera under 16 families depend on birds for pollination and/or seed dispersal. Occurrence of greater bird diversity and abundance of avian communities were recorded highest in the winter season in the BUC premises. In the different seasons, the BUC had varying community structure of birds between the study years. BUC suffers from numerous threats namely grass cutting, fire and grazing of domestic animals. Conservation methods needed for habitat management are restoration of vegetation and wetlands, and increase plant and tree diversity to protect the ecosystem of BUC habitat and to preserve its diversity of avifauna.

A global, remote sensing‐based characterization of terrestrial habitat heterogeneity for biodiversity and ecosystem modelling

AbstractAimHabitat heterogeneity has long been recognized as a key landscape characteristic determining biodiversity patterns. However, a lack of standardized, large‐scale, high‐resolution and temporally updatable heterogeneity information based on direct observations has limited our understanding of this connection and its effective use for biodiversity conservation. To address this, we develop here remote sensing‐based metrics to characterize global habitat heterogeneity at 1‐km resolution and assess their value for biodiversity modelling.LocationGlobal.MethodsWe develop 14 heterogeneity metrics (available athttp://www.earthenv.org) based on the textural features of the enhanced vegetation index (EVI) imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS), and closely examine a complementary core set of six of these metrics. We evaluate their ability to provide fine‐grain habitat heterogeneity by comparing the heterogeneity information captured by them with that measured by 30‐m Landsat‐based land‐cover data. Using spatial autoregressive models, we then compare their utility with that of more conventional metrics (derived from topography or categorical land‐cover data) for modelling the species richness of bird communities across the conterminousUnitedStates based onBreedingBirdSurvey data.ResultsThe newly derived metrics capture different aspects of habitat heterogeneity and provide fine‐grain information for locations deemed homogeneous by traditional land‐cover classifications at both continental and global extents. Most of them strongly exceed conventional heterogeneity variables in capturing the spatial variation in bird species richness, withHomogeneity emerging as the strongest predictor.Main conclusionsThis study develops and validates the performance of readily usable metrics of textural measures capturing fine‐grain habitat heterogeneity. The presented metrics outperform conventional measures in capturing detailed spatial variation in habitats and in predicting key biodiversity patterns. They provide a rigorous and comparable basis for understanding heterogeneity–diversity relationships, and offer a powerful tool for monitoring and understanding the responses of biodiversity and ecosystems to the changing environment.

Changes in bird community composition in the Czech Republic from 1982 to 2004: increasing biotic homogenization, impacts of warming climate, but no trend in species richness

Recent major environmental changes could lead to homogenization in the composition of plant and animal communities, with generalist species replacing more specialized species, as well as to the increased domination of species adapted to warmer climatic conditions. Using common bird monitoring data, we have tested whether these patterns can be observed in the long-term changes in the structure and species richness of bird communities in the Czech Republic. We focused on a comparison of two time periods (1982–1990 and 1991–2004) that differ in land use (high agricultural intensity in the former, and a drop in agricultural intensity accompanied by forest expansion in the latter). We found that bird communities became less specialized and that this decline in specialization did not change after 1990. In contrast, taxonomic homogenization increased during the first time period but declined at the beginning of the second one. Moreover, the community composition developed towards a dominance of species breeding in warmer climates, and this change coincided with an increase in spring temperatures. Therefore, it would appear that both functional and taxonomic homogenization took place in the 1980s but the latter did not continue in subsequent decades. Species richness of local bird communities did not show any trend over time. We suggest that climate warming might be an important driving force of changes in the bird community composition in the Czech Republic, but the role of land-use changes is less clear, although it is probable that habitat specialists probably did not benefit from lower intensity of agricultural activities and increased forest cover.

Preferencias de hábitat, densidad y diversidad de las comunidades de aves en Tenerife (Islas Canarias)

Species–specific habitat preferences, density and species richness of bird communities in Teneriffe (Canary Islands) Bird distribution and abundance are described and analyzed in Teneriffe (Canary Islands). Inter–habitat differences in density, diversity and species richness are shown in table 1. Figure 2 shows the main determinants of bird species richness in Teneriffe, and tables 2 and 3 and figure 3 show the species–specific patterns of spatial variation abundance (more detailed for Anthus berthelotii, Fringilla coelebs canariensis, Fringilla teydea, Parus caeruleus teneriffae, Phylloscopus canariensis, Regulus teneriffae, Serinus canarius and Turdus merula cabrerae). Deeply transformed environments due to human impact (urban habitats, agricultural mosaics, banana plantations) have high bird densities and species richness, even higher than those measured in native, unmodified habitats such as laurel forests or mature pinewoods. Urban environments in Teneriffe are very permeable to native bird fauna, as they have been occupied by many widespread endemic species/subspecies. Many of the endemic, well defined species or subspecies of island birds have high population densities within native, untransformed habitats. Density compensation and niche expansion is not a common phenomenon in the avifauna of Teneriffe. Nevertheless, all species/subspecies broadening the inter–habitat or altitudinal distribution are endemic of the Canary Islands.

Effects of habitat degradation on avian guilds in East African papyrus Cyperus papyrus swamps

The density and species richness of bird communities in disturbed and undisturbed stands of papyrus Cyperus papyrus were compared. Point counts, corrected for different probabilities of detection in different swamps, suggested that the species richness of bird communities in stands of papyrus disturbed by burning, grazing or pollution was higher than in nearby stands that were not disturbed. However, there were fewer species and individuals of highly specialized birds or species characteristic of papyrus, in disturbed stands than in undisturbed swamps. At < 1 ha-1, the density of Papyrus Gonolek Laniarius mufumbiri in Ugandan swamps was, for example, significantly lower in polluted and burnt sites than in undisturbed papyrus where up to 13 ha-1 were recorded in the centre of swamps. White-winged Swamp Warbler Bradypterus carpalis was only recorded in undisturbed papyrus. In the papyrus that fringes Lake Naivasha in Kenya, outside the geographical range of species restricted to papyrus, disturbance in the form of grazing selects against species classified as swamp-reliant. Species classified as generalist users of papyrus were much less sensitive to disturbance than specialists. The density of swamp specialists was also lower near the edge of swamps, where total species richness was higher. These results are discussed in relation to conservation management of papyrus swamps in East Africa.

ESTRUCTURA Y UTILIZACION DEL FOLLAJE DE LAS COMUNIDADES DE PAJAROS EN BOSQUES TEMPLADOS DEL VALLE DE MEXICO

Températe forests are distributed over very extensivo areas in North America but in tropical Middle America are limited to montane zones, and at the present time these montane forests are threatened by man because of overpopulation. I studied the structure and use of foliage of bird communities in montane températe forests of , the Valley of México. In August and September of 1981 I censused bird communities in six températe forest study areas one each in oak woodland and pine-alder forest, and two each in pine forest and firforest using the variable circular-plot method. Overall bird densities were greater in broad-leaved forests than in coniferous forests. Species richness was similar between broad-leaved and pine forests but generally lower in fir forests. A similar trend was shown by bird species diversity (BSD). The oak woodland bird community was the most distinctive, whereas the pine-alder one was similar to the fir forests. Bird communities of the two pine forests had low similarity indices, whereas communities of fir forests had the highest índices. Qranivorous birds were very important in pine forests, whereas insectivores were the most important in broad-leaved and fir forests. Profiles of foliage stratification were used selectively by all the bird communities, and profiles of utiiization were significantly different between August and September for all the communities except that of the pine-alder forest. Among dietary categories and guilds, all but the seed-eaters used the profile of foliage stratification very selectively; this selectivity was especially marked for the salliers and the foliage gelaners. In a latitudinal gradient of températe forests over western North America and México, there were not big differences in species richness of bird communities from broad-leaved and mixed-conifer forests, but there was a decrease in the number of species from pine forests as latitude decreased. BSD decreased southwards in the broad-leaved forests and only slightly in mixed-conifer forests, whereas in pine forests BSD increased. Seed-eaters were relatively more abundant in the northem forests, whereas foliage gleaners were the most important in Southern forests, but not in the pine forests.