scholarly journals Forest degradation, not loss, drives widespread avian population declines

2021 ◽  
Author(s):  
Matthew Betts ◽  
Zhiqiang Yang ◽  
Adam Hadley ◽  
Josee Rousseau ◽  
Joseph Northrup ◽  
...  
Keyword(s):  
Habitat Loss ◽  
Forest Cover ◽  
Bird Species ◽  
Forest Degradation ◽  
Breeding Habitat ◽  
Population Declines ◽  
Distribution Models ◽  
Eastern Canada ◽  
Bird Abundance

Abstract In many regions of the world, forest management has reduced old forest and simplified forest structure and composition via reliance on monoculture tree plantations. We hypothesized that such forest degradation has resulted in long-term habitat loss for forest-associated bird species of eastern Canada (130,017 km2) which, in turn, has affected bird population declines. Back-cast species distribution models revealed that despite little change in overall forest cover, breeding habitat loss occurred for 66% of the 54 most common species from 1985-2020. This habitat loss was strongly associated with population declines for 72% of species, as quantified in an independent, long-term dataset. Since 1985, net forest bird abundance has declined in this region by an estimated 33-104 million birds due to habitat loss alone. The effects of forest degradation may therefore be a primary cause of biodiversity decline in managed forest landscapes.  

Cryptic and cumulative impacts on the wintering habitat of the endangered black-faced spoonbill (Platalea minor) risk its long-term viability

2017 ◽  
Vol 45 (2) ◽  
pp. 147-154 ◽  
Author(s):  
EVAN J. PICKETT ◽  
MELANIE CHAN ◽  
WENDA CHENG ◽  
JOHN ALLCOCK ◽  
SIMBA CHAN ◽  
...  
Keyword(s):  
Climate Change ◽  
Habitat Loss ◽  
Population Change ◽  
Anthropogenic Impacts ◽  
Population Viability Analysis ◽  
Cumulative Impacts ◽  
Population Declines ◽  
Distribution Models ◽  
Waterbird Species

SUMMARYThe East Asian–Australasian flyway contains some of the most threatened habitats in the world, with at least 155 waterbird species reliant on the tidal habitats it comprises. The black-faced spoonbill (Platalea minor) is an iconic endangered species distributed across the coast of East Asia. Its population suffered a severe decline into the 1990s, but extensive monitoring and conservation interventions have aided a substantial recovery of the species. We used a population viability analysis based on data collected over the past two decades in conjunction with species distribution models to project spatially explicit models of population change for the next 35 years. Over nearly all scenarios of habitat loss and climate change, the global spoonbill population was projected to increase in the short-term due to low population numbers likely well below current population carrying capacities. However, climate change and habitat loss together threaten the recovery of the spoonbill population such that, by 2050, population declines are apparent as a consequence of these cumulative impacts. These threats are also cryptic and represent a challenge to the conservation of species recovering from anthropogenic impacts; observed population increases can hide large reductions in habitat suitability that threaten the long-term viability of species.

Early seral hardwood vegetation increases adult and fledgling bird abundance in Douglas-fir plantations of the Oregon Coast Range, USA

2012 ◽  
Vol 42 (5) ◽  
pp. 918-933 ◽  
Author(s):  
Tana M. Ellis ◽  
Andrew J. Kroll ◽  
Matthew G. Betts
Keyword(s):  
Forest Management ◽  
Pacific Northwest ◽  
Management Practices ◽  
Bird Species ◽  
Relative Magnitude ◽  
Breeding Habitat ◽  
Population Declines ◽  
Private Lands ◽  
Bird Abundance ◽  
Catharus Ustulatus

Recent evidence suggests that population declines of bird species associated with early-successional forest conditions may be associated with reduced quality of breeding habitat. Increasing intensity of forest management on private lands and decreased harvest rates on federal lands in the Pacific Northwest, USA, have resulted in a loss of diverse young forest stands, typically called early seral forest. Previous studies suggest that the amount of early seral broadleaf cover within conifer forests is linked to the composition of foliage-gleaning bird communities. However, information regarding productivity and juvenile use of post-breeding habitat in highly modified plantation habitat is lacking. We examined the relationship between vegetation structure resulting from intensive forest management practices and the abundance of five species of leaf-gleaning, neotropical migrants: orange-crowned warbler ( Oreothlypis celata (Say, 1823)), Wilson’s warbler ( Wilsonia pusilla (A. Wilson, 1811)), MacGillivray’s warbler ( Oporornis tolmiei (J.K. Townsend, 1839)), Swainson’s thrush ( Catharus ustulatus (Nuttall, 1840)), and black-headed grosbeak ( Pheucticus melanocephalus (Swainson, 1827)). All species, except MacGillivray’s warbler, showed positive associations with the amount of early seral hardwood cover as fledglings, breeding adults, or both. However, the relative magnitude of these associations varied, suggesting that other factors may also have influenced avian responses. Abundances of breeding pairs and young are likely to show positive responses to management practices that increase early seral hardwood cover in regenerating stands. If adopted at landscape and regional scales, such practices may positively influence population trends of several declining bird species.

scholarly journals Forest fragmentation in the temperate zone and its effects on migratory songbirds

1994 ◽  
Vol 4 (2-3) ◽  
pp. 233-249 ◽  
Author(s):  
Scott K. Robinson ◽  
David S. Wilcove
Keyword(s):  
Forest Fragmentation ◽  
Tropical Deforestation ◽  
Temperate Zone ◽  
Breeding Habitat ◽  
Neotropical Migrants ◽  
Population Declines ◽  
Migratory Songbirds

SummaryAlthough much attention has been paid to the impacts of tropical deforestation on populations of Neotropical migrants, fragmentation of breeding habitat may be an equally serious problem for many of these birds. Populations of many migrant songbirds have been declining in recent decades, especially within small woodlots. Censuses from woodlots of different sizes also consistently show that many migrant songbirds are area-sensitive, i.e. they are absent from all but the largest woodlots in a region. In contrast, long-term censuses from large, unfragmented forests show few consistent patterns of decline in Neotropical migrants. Population declines are therefore linked to forest fragmentation because they are most pronounced in small, isolated woodlots.

scholarly journals The decline of the endemic Fijian crested iguana Brachylophus vitiensis in the Yasawa and Mamanuca archipelagos, western Fiji

Oryx ◽  
2007 ◽  
Vol 41 (1) ◽  
pp. 44-50 ◽  
Author(s):  
Peter S. Harlow ◽  
Martin Fisher ◽  
Marika Tuiwawa ◽  
Pita N. Biciloa ◽  
Jorge M. Palmeirim ◽  
...  
Keyword(s):  
Habitat Loss ◽  
Forest Fires ◽  
Population Decline ◽  
Forest Degradation ◽  
Iucn Red List ◽  
Red List ◽  
Critically Endangered ◽  
Introduced Predators ◽  
Free Ranging

The endemic Fijian crested iguana Brachylophus vitiensis, categorized as Critically Endangered on the IUCN Red List, has been recorded from several islands in western Fiji. We conducted a survey for the crested iguana on 12 uninhabited and five inhabited islands in the Yasawa and Mamanuca archipelagos of western Fiji in September 2000. Night searches for sleeping iguanas along a total of 11.2 km of forest transects suggest that crested iguanas are either extremely rare or extinct on all of these islands. Although we collectively searched a total of 44 km of transect over 123 person hours, we located crested iguanas on only four islands: three small uninhabited islands (all <73 ha) and one large inhabited island (22 km). In July 2003 we resurveyed two islands identified as having the best potential for the long-term conservation of crested iguanas, and found that populations were continuing to decline. We suggest that the scarcity of crested iguanas on all islands surveyed is due to the combination of habitat loss and the introduction of exotic predators. All islands surveyed have free ranging goats, forest fires have occurred repeatedly over the last few decades, and feral cats are established on many islands. To reverse the population decline of this species immediate intervention is required on selected islands to halt continuing forest degradation and to clarify the effects of introduced predators.

scholarly journals Conservation status of birds on Mindoro, Philippines

1992 ◽  
Vol 2 (4) ◽  
pp. 303-325 ◽  
Author(s):  
Guy C. L. Dutson ◽  
Tom D. Evans ◽  
Thomas M. Brooks ◽  
Desiderio C. Asane ◽  
Robert J. Timmins ◽  
...  
Keyword(s):  
Forest Cover ◽  
Conservation Status ◽  
Bird Species ◽  
Concerted Action ◽  
Medium Term ◽  
Lowland Forest ◽  
Risk Of Extinction ◽  
Forest Remnants ◽  
The Status

SummaryFour weeks of fieldwork in the forests of Mindoro, Philippines, in 1991 has elucidated the status of the six bird species endemic to the island. Of these, Ducula mindorensis and Otus mindorensis are high-altitude species with restricted ranges and in need of active conservation in the medium term. Three of the four lowland species, Gallicolumba platenae, Centropus steerü and Penelopides mindorensis are under immediate threat of extinction through forest clearance and fragmentation, while the fourth, Dicaeum retrocinctum, s i not under immediate threat but is certainly at risk of extinction in the long term. Whilst deforestation is an enormous problem across the entire Philippines, Mindoro is the smallest centre of endemism with the least forest cover after the Sulu Islands. Extinctions are believed inevitable within the next 10 years unless concerted action is urgently taken. The Halcon range must receive attention in order to conserve the montane species, but more urgent by far is the preservation of lowland forest remnants, concentrating on central-west Mindoro.

scholarly journals Efecto de la estacionalidad y lluvias en la avifauna del Chaco Serrano Austral, Argentina

2017 ◽  
Vol 65 (3) ◽  
pp. 953
Author(s):  
Gustavo Alfredo Fava ◽  
Juan Carlos Acosta ◽  
Graciela Mirta Blanco
Keyword(s):  
Bird Species ◽  
Reproductive Activity ◽  
Breeding Habitat ◽  
Bird Abundance ◽  
Group Management ◽  
Natural Park ◽  
Chaco Serrano ◽  
Site Survey ◽  
Migrant Bird ◽  
Resident Bird

In subtropical regions like the Chaco Serrano (33° S), rainfall has a marked seasonality, and water flood, caused by heavy rains, may have important consequences for dependent ecosystems. Conversely, the high pressure on available resources during dry periods can also affect the fauna diversity and distribution. Even though birds have shown to be excellent ecological indicators of these shifts in the environment, currently little is known about the avifauna of the Argentine Chaco Serrano phytogeographic district. Our aim was to study the resident bird population status in the Southern Chaco Serrano, its fluctuations in richness and abundance, and its relationship to seasonal variations, in monthly and annual hydroperiods. In order to assess the resident bird status over a two year period (2011 Mar.-2013 Feb.) we carried out 18 sampling surveys during pre-breeding (spring), breeding (summer) and non breeding periods (autumn-winter), in the Northeastern part of the Valle Fértil Natural Park, San Juan province, Argentina. During each site survey, we recorded bird assemblages found in six transects, and obtained bird abundance and species diversity. A mixed general linear model was employed to evaluate relationships between the studied variables. We found a total of 98 species of birds belonging to 33 families (44 resident species, 23 spring visitors, six summer visitors, two winter visitors and 23 with scarce registers). We also registered 68 of these species in both hydroperiods, 28 only during rainy periods and only two during the dry period. Both richness and abundance showed the highest values during the pre-breeding and rainy seasons, while different tendencies were detected during the isolated monthly rainfalls. These changes in bird densities were associated with the arrival of migratory species, mainly spring visitors, and probably in relationship with their reproductive activity, and to seasonal fluctuations in food resources. The Southern Chaco Serrano is a subtropical semiarid place that seems to be an important breeding habitat for many migrant bird species, which in turn promoted seasonal changes in species density and diversity, mainly during rainy years. This work contributed to our understanding on the causes of richness and abundance variations on birds, and will contribute to this important group management and conservation in this area.

scholarly journals Habitat suitability for primate conservation in north-east Brazil

Oryx ◽  
2020 ◽  
Vol 54 (6) ◽  
pp. 803-813
Author(s):  
Bárbara Moraes ◽  
Orly Razgour ◽  
João Pedro Souza-Alves ◽  
Jean P. Boubli ◽  
Bruna Bezerra
Keyword(s):  
Climate Change ◽  
Protected Areas ◽  
Forest Restoration ◽  
Forest Cover ◽  
Change Scenario ◽  
Distribution Models ◽  
Term Survival ◽  
Priority Areas ◽  
North East

AbstractBrazil has a high diversity of primates, but increasing anthropogenic pressures and climate change could influence forest cover in the country and cause future changes in the distribution of primate populations. Here we aim to assess the long-term suitability of habitats for the conservation of three threatened Brazilian primates (Alouatta belzebul, Sapajus flavius and Sapajus libidinosus) through (1) estimating their current and future distributions using species distribution models, (2) evaluating how much of the areas projected to be suitable is represented within protected areas and priority areas for biodiversity conservation, and (3) assessing the extent of remaining forest cover in areas predicted to be suitable for these species. We found that 88% of the suitable areas are outside protected areas and only 24% are located in areas with forest cover. Although not within protected areas, 27% of the climatically suitable areas are considered priority areas for conservation. Future projections, considering a severe climate change scenario, indicate that A. belzebul, S. flavius and S. libidinosus may lose up to 94, 98 and 54% of their suitable range, respectively. The establishment of primate populations and their long-term survival in these areas are at risk. Mitigation actions such as the implementation of new protected areas, forest restoration and reduction of greenhouse gas emissions will be essential for the conservation of Brazilian primates.

Habitat openness and edge avoidance predict Saltmarsh Sparrow abundance better than habitat area

The Condor ◽  
2020 ◽  
Vol 122 (3) ◽  
Author(s):  
Hallie Marshall ◽  
Erik J Blomberg ◽  
Valerie Watson ◽  
Meaghan Conway ◽  
Jonathan B Cohen ◽  
...  
Keyword(s):  
Population Decline ◽  
Bird Species ◽  
Breeding Habitat ◽  
Tidal Marshes ◽  
Bird Abundance ◽  
Marsh Edge ◽  
Marsh Bird ◽  
Saltmarsh Sparrow ◽  
Habitat Features ◽  
Better Than

Abstract The Saltmarsh Sparrow (Ammospiza caudacuta) is a tidal marsh bird facing rapid population decline throughout its range, largely caused by degradation and loss of breeding habitat. Thus, there is a need to preserve tidal marshes in the northeastern United States, but to do so requires an understanding of the habitat features that support robust populations. Previous studies have shown Saltmarsh Sparrow abundance increases with marsh size, but in similar bird species, area sensitivity is more directly linked to edge avoidance. Whether additional landscape features affect the abundance of Saltmarsh Sparrows is unknown. We explored how the height of objects on the horizon, an index of habitat openness, affected the abundance of Saltmarsh Sparrows. Our primary goal was to determine whether the angle to the highest point on the horizon (“angle to maximum horizon”) predicted abundance better than marsh area or distance to the marsh edge. We used N-mixture models to evaluate the combination of spatial factors that best predicted Saltmarsh Sparrow abundance while also accounting for survey-level variables that could influence detection probability. We found that the interaction between distance to edge and angle to maximum horizon best predicted abundance. Taller objects on the horizon were negatively correlated with bird abundance, and this effect was strongest within 50 m of the marsh edge. When we considered the predictive powers of patch area, distance to edge, and angle to maximum horizon individually, angle to maximum horizon was the best single predictor. We found the highest abundance of Saltmarsh Sparrows at point locations where the angle to maximum horizon was 0.0°, and at angles greater than 12° the predicted abundance fell below 1 bird per survey point. We propose that managers should prioritize marsh openness and experimentally test the effect of marsh edge manipulations when making conservation decisions for this rapidly declining species.

scholarly journals Trade-driven trapping dampens the biodiversity benefits of forest restoration in Southeast Asia

2021 ◽  
Author(s):  
H S Sathya Chandra Sagar ◽  
James J Gilroy ◽  
Tom Swinfield ◽  
Ding Li Yong ◽  
Elva Gemita ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Tropical Forest ◽  
Forest Restoration ◽  
Bird Species ◽  
Forest Degradation ◽  
Forest Recovery ◽  
Avian Community ◽  
Pet Trade ◽  
Tropical Forest Restoration

Tropical forest restoration stands to deliver important conservation gains in lowland Southeast Asia, which has suffered some of the world's highest rates of forest degradation and loss. This promise, however, may be undermined by defaunation driven by ubiquitous wildlife trapping in the region, particularly for forest birds that are part of the multi-million-dollar pet trade. To date, quantification of the impacts of trade-driven trapping on rates of biodiversity recovery from forest restoration has been limited. Here, we use a unique long-term survey dataset to ask how trade-driven trapping may interfere with the expected recovery of avian community under forest restoration, at a flagship ecosystem restoration site in the lowland rainforests of Sumatra, Indonesia. We show that tropical forest restoration is associated with the increases in the abundance of 88% of bird species over time. However, impacts of trapping within more accessible areas of the forest meant that this recovery was dampened for 74% of bird species, relative to levels expected as a result of the magnitude of forest recovery observed. Most species (80%) showed increasingly positive relationships between abundance and site remoteness over the period, a pattern that was found for both species targeted for the pet trade (85% of species) and those trapped opportunistically or as 'bycatch' (78% of species). We emphasize the urgency of tackling the emerging threat of pet trade to Southeast Asia's avian diversity, not least to ensure the effectiveness of efforts towards forest restoration.

scholarly journals Monitoring Breeding Bird Populations in Grand Teton National Park: 1995-1997

1997 ◽  
Vol 21 ◽  
pp. 13-25
Author(s):  
Martin Cody ◽  
Stephen Cain
Keyword(s):  
Breeding Season ◽  
National Park ◽  
Management Strategies ◽  
Bird Species ◽  
Breeding Habitat ◽  
Breeding Bird ◽  
Grand Teton National Park ◽  
Bird Populations ◽  
The Impact

In summer 1997 our NPS-funded project # CA-1460-5-0010, covering a 3-y period from summer 1995 through summer 1997, was completed. The immediate goals of the project were to instigate a system for monitoring the densities of breeding bird species, by establishment of flxed sites as a basis for a long term monitoring plan and of census protocols that can detect changes of breeding species and their densities over successive years. The monitoring scheme is conducted largely within Grand Teton National Park (GTNP), but covers habitats and an avifauna representative of the Greater Yellowstone Ecosystem (GYE) and the central-northern Rocky Mountains in general. The project emphasizes the need for long­term and on-going studies on breeding bird species and densities and their importance as a tool for evaluating the impact of both local and distant influences on breeding bird populations. For residents, species that remain all year in or near the breeding habitat, local effects include those operating on-site during the non-breeding season as well as during the breeding season. For migrant species, those that breed on-site but leave to spend the non-breeding season in other locations, often distant and usually of quite different habitat composition, there are both on-site influences on breeding population densities, such as inter-year changes in vegetation structure and productivity, and off-site or distant influences, including factors that affect over-wintering success in the non­breeding habitat and others that influence a successful transit between wintering and breeding grounds. The assessment of long-term trends in bird densities may be used as a form of bioassay of the state of the local environments. Information from such studies can provide region-wide indicators that, given a sufficiently comprehensive data base, can segregate local from distant influences on populations. Such indicators can be incorporated into management strategies to aid in determining which local strategies may be necessary (and feasible) to help maintain the biota.

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