scholarly journals Threatened birds of the Angolan Central Escarpment: distribution and response to habitat change at Kumbira Forest

Oryx ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 727-734 ◽  
Author(s):  
Aimy Cáceres ◽  
Martim Melo ◽  
Jos Barlow ◽  
Paulo Cardoso ◽  
Francisco Maiato ◽  
...  
Keyword(s):  
Forest Cover ◽  
Land Use Changes ◽  
Secondary Growth ◽  
Bird Species ◽  
Bird Community ◽  
Old Growth ◽  
Forest Patches ◽  
Old Growth Forest ◽  
Remote Sensing Techniques ◽  
Representative Area

AbstractKumbira Forest is the best representative area of Angola's Central Escarpment and the only site known to hold significant populations of four of the five threatened endemic bird species of this habitat. However, the forest is disappearing as a result of human activities. Remote-sensing techniques were used to assess changes in forest cover, and bird and habitat surveys were performed to assess the effect of land-use changes on endemic species and the bird community. No relationships could be established between the presence of endemics and habitat and landscape variables. This lack of effect may be attributable to the low number of records and compounded by the mosaic structure of the landscape. Although forest cover has been maintained in Kumbira, old-growth forest has been replaced by secondary growth in many areas. Nevertheless these secondary-growth forest patches can maintain a bird community similar to that found in old-growth forest.

scholarly journals Die Suche nach altem Wald in der Schweiz

2015 ◽  
Vol 166 (2) ◽  
pp. 67-74 ◽  
Author(s):  
Rita Bütler ◽  
Markus Bolliger ◽  
Brigitte Commarmot
Keyword(s):  
Forest Cover ◽  
Dead Wood ◽  
Stand Structure ◽  
National Forest Inventory ◽  
Old Growth ◽  
Forest Patches ◽  
Natural Processes ◽  
Old Growth Forest ◽  
Veteran Trees ◽  
Old Growth Forests

The search for old-growth forests in Switzerland Old-growth forests and stands have multiple values, such as biological, scientific, socioeconomic, aesthetic, spiritual and cultural ones, but they are very rare in central Europe. Currently, an overview about the existence and size of old-growth forest patches in Switzerland is missing. We propose a definition for old-growth forests worth preserving based on ten criteria: 1) presence of veteran trees, 2) significant biomass, 3) heterogeneous stand structure including senescent and decaying stages, 4) presence of natural processes and disturbances, 5) high dead wood volume (at least 30 m3/ha) and a large diversity of dimensions and decay stages of dead wood pieces, 6) autochthonous tree species, 7) diverse and natural species assemblages, 8) only extensive or no harvesting for the last 50 years, 9) long continuity of forest cover, 10) minimal area of 30 ha for old-growth forests and 1 ha for old-growth stands. When searching for old-growth forests and stands worth preserving, quantitative criteria from the National Forest Inventory and other sources should also be used. We call on all forest specialists to identify old-growth patches, to inform the population and decision makers about their high value, and to protect them in an adequate manner as a unique natural heritage.

Fuel succession in a western hemlock/Douglas-fir forest

1987 ◽  
Vol 17 (7) ◽  
pp. 697-704 ◽  
Author(s):  
James K. Agee ◽  
Mark H. Huff
Keyword(s):  
Aboveground Biomass ◽  
Fire Behavior ◽  
Herb Layer ◽  
Old Growth ◽  
Forest Patches ◽  
Surface Fire ◽  
Old Growth Forest ◽  
Tree Component ◽  
Natural Stands ◽  
Over Time

Fuel succession was quantified for a 515-year chronosequence in a Tsugaheterophylla/Pseudotsugamenziesii forest. Postfire stand ages selected were 1, 3, 19, 110, 181, and 515. After initial reductions due to mortality from fire in the first 3 years, live aboveground biomass in the tree component increased over time to over 1100 t/ha. Shrub and herb layer biomass was highest in year 19 and year 515. Dead aboveground biomass had different trends for different fuel size classes; normalized fuel loadings of five dead and down fuel categories peaked at four different stand ages: 1-h and 10-h timelag (TL) fuels, age 1; 100-h TL fuels, age 19; 1000-h TL fuels, age 110; >1000-h TL fuels, age 515. Surface fire behavior was highest early in the sere and lowest at ages 110–181. Old-growth forest patches appear to be best buffered against forest fire by mature forest patches rather than old growth or recently burned natural stands.

scholarly journals Abundance and patterns of rarity of Polylepis birds in the Cordillera Vilcanota, southern Perú: implications for habitat management strategies

2008 ◽  
Vol 18 (2) ◽  
pp. 164-180 ◽  
Author(s):  
Huw Lloyd
Keyword(s):  
Species Richness ◽  
Habitat Loss ◽  
Habitat Management ◽  
Habitat Restoration ◽  
Management Strategies ◽  
Distance Sampling ◽  
Bird Species ◽  
Bird Community ◽  
Forest Patches ◽  
Lowland Forest

AbstractPoint count distance sampling surveys were conducted at three sites in the Cordillera Vilcanota to determine whether variation in high-Andean species richness, diversity and abundance was a reflection of Polylepis habitat quantity. Bird community and abundance measures revealed that there was considerably variation in bird species richness, diversity and mean encounter rates between large, medium, and small forest patches. Densities of Polylepis-dependent bird species (including five globally-threatened and eight restricted-range species) were greater in larger forest patches and differed significantly between different patch size categories. Density estimates for matrix-dependent species were higher in smaller Polylepis patches indicating that the matrix exerts an influence on bird species composition and abundance in remnant Polylepis forests, particularly smaller patches. Comparison of lowland forest habitat specialists using three categories of rarity revealed that between 19–22% of all Polylepis-dependent species were intrinsically rare within larger forest patches, and a greater number (34–74%) were rare in smaller forest patches. Population estimates for all species, in particular for all threatened species, were extremely low, numbering ⩽ 10 individuals at nine of the ten sites examined. The results suggest that declines in the densities of certain Polylepis birds may be predictable following habitat loss and that these patterns of rarity should govern population recovery goals through appropriate habitat restoration strategies. Such strategies are urgently required and must be designed to prevent further habitat loss, and to increase Polylepis habitat quantity to boost threatened bird populations in the Cordillera Vilcanota.Evaluaciones de distancias de puntos de conteo fueron conducidas en tres lugares en la Cordillera Vilcanota para determinar si la variación en la riqueza, diversidad y abundancia de las especies de los Andes altos, era un reflejo de la cantidad de hábitats de Polylepis. La comunidad de aves y su abundancia revelaron que hubo una considerable variación en la riqueza de especies, diversidad y la media encontrada en rangos parches de bosque comprendidos entre grandes, medios y pequeãos. La densidad de especies de aves dependientes de Polylepis (incluyendo cinco amenazados globalmente y ocho especies con rango restringido) fueron mayores en parches grandes de bosque y difirieron significativamente entre diferentes categorías de tamaãos de parche. La densidad estimada para especies matriz-dependientes fue mayor en pequeãos parches de Polylepis indicando que la matriz ejerce una influencia en la composición de especies de aves y abundancia en vestigios de bosques de Polylepis, particularmente parches pequeãos. En comparación con especialistas de hábitat de bosque bajo, empleando tres categorías de rareza revelaron que entre 19–22% de todos las especies dependientes de Polylepis fueron intrínsicamente raras dentro de parches grandes de bosque, y un número mayor (34–74%) fueron raras en los parches pequeãos de bosque. La población estimada para todas las especies, en particular para todas las especies amenazadas, fue extremadamente baja, contando ⩽ 10 individuos en nueve de los 10 sitios examinados. El resultado sugiere que la disminución en la densidad de ciertas aves de Polylepis se podría predecir después de la pérdida de hábitat y que esos patrones de rareza podrían servir como objetivos para la recuperación de la población a través de estrategias de restauración de hábitats apropiados. Este tipo de estrategias son requeridas con urgencia y deberían estar diseãadas para prevenir futuras pérdidas de hábitats, incrementar la cantidad de hábitat de Polylepis para aumentar la población de aves amenazadas en la Cordillera Vilcanota.

Deforestation and forest regeneration following small-scale gold mining in the Amazon: the case of Suriname

2001 ◽  
Vol 28 (2) ◽  
pp. 117-126 ◽  
Author(s):  
Garry D. Peterson ◽  
Marieke Heemskerk
Keyword(s):  
Gold Mining ◽  
Forest Cover ◽  
Qualitative Interviews ◽  
Gold Rush ◽  
Forest Recovery ◽  
Small Scale ◽  
Old Growth ◽  
Mining Sites ◽  
Mining Areas ◽  
Old Growth Forest

Despite scientific concern about Amazon deforestation and the impacts of the Amazon gold rush, few researchers have assessed the long-term impacts of small-scale gold mining on forest cover. This study estimates deforestation from gold mining and analyses the regeneration of abandoned mining areas in the Suriname Amazon. Fieldwork in December 1998 included observations and ecological measurements, as well as qualitative interviews with local miners about mining history and technology. Vegetation cover of abandoned mining sites of different ages was compared with that in old-growth forest. By present estimates, gold miners clear 48–96 km2 of old-growth forest in Suriname annually. Based on different assumptions about changes in technology and the amount of mining that takes place on previously mined sites, cumulative deforestation is expected to reach 750–2280 km2 by 2010. Furthermore, the analysis of abandoned mining sites suggests that forest recovery following mining is slow and qualitatively inferior compared to regeneration following other land uses. Unlike areas in nearby old-growth forest, large parts of mined areas remain bare ground, grass, and standing water. The area deforested by mining may seem relatively small, but given the slow forest recovery and the concentration of mining in selected areas, small-scale gold mining is expected to reduce local forest cover and ecosystem services in regions where mining takes place.

scholarly journals Population densities of understorey birds across a habitat gradient in Palawan, Philippines: implications for conservation

Oryx ◽  
2011 ◽  
Vol 45 (2) ◽  
pp. 234-242 ◽  
Author(s):  
N.A.D. Mallari ◽  
N.J. Collar ◽  
D.C. Lee ◽  
P.J.K. McGowan ◽  
R. Wilkinson ◽  
...  
Keyword(s):  
Threatened Species ◽  
Bird Species ◽  
The Philippines ◽  
Area Network ◽  
Old Growth ◽  
Density Estimates ◽  
Old Growth Forest ◽  
Habitat Gradient ◽  
Key Species ◽  
Large Trees

AbstractThere is widespread concern for many understorey and ground-dwelling bird species in the Philippines that appear intolerant of forest alteration. We present density estimates for 18 key bird species in old growth forest, advanced and early secondary growth and active cultivation within the Puerto Princesa Subterranean River National Park in Palawan. Six species were not recorded in cultivation and the abundance of these and several others increased along the successional gradient from cultivation to old growth forest. Eleven species, including five endemics and three of four threatened species, had highest density estimates in old growth forest. However, several species had high density estimates in the heavily disturbed habitats and every habitat type held highest densities of at least one of the bird species. The commonest habitat association across the bird community was a preference for areas containing large trees, indicating the importance of retention of such trees in allowing suitable ground and understorey microhabitats to persist. Old growth forests have the highest conservation value for Palawan’s endemic birds and, while some species thrive in the anthropogenic habitats that occur within the Park, the present extent of cultivation and associated successional stages within its boundaries should not be increased. We caution against extrapolation of the abundance figures from the Park to the whole island but we suggest that population sizes for the threatened species are likely to be much greater than previously thought. We urge authorities to strengthen management within the protected area network in Palawan to ensure survival of key species.

scholarly journals Bird Occupancy of a Neotropical Forest Fragment Is Mostly Stable over 17 Years but Influenced by Forest Age

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 50
Author(s):  
Marconi Campos-Cerqueira ◽  
W. Douglas Robinson ◽  
Gabriel Augusto Leite ◽  
T. Mitchell Aide
Keyword(s):  
Bird Species ◽  
Barro Colorado Island ◽  
Tropical Species ◽  
Forest Age ◽  
Forest Fragment ◽  
Long Term Effects ◽  
Old Growth ◽  
Data Set ◽  
Old Growth Forest

The effects of forest degradation, fragmentation, and climate change occur over long time periods, yet relatively few data are available to evaluate the long-term effects of these disturbances on tropical species occurrence. Here, we quantified changes in occupancy of 50 bird species over 17 years on Barro Colorado Island (BCI), Panama, a model system for the long-term effects of habitat fragmentation. The historical data set (2002–2005) was based on point counts, whereas the contemporary data set (2018) was based on acoustic monitoring. For most species, there was no significant change in occupancy; however, the occupancy of four species (Tinamus major, Polioptila plumbea, Myiarchus tuberculifer, and Ceratopipra mentalis) increased significantly, and the occupancy of three species (Saltator grossus, Melanerpes pucherani, and Cyanoloxia cyanoides) decreased significantly. Forest age explained the majority of occupancy variation and affected the occupancy of more bird species than survey period or elevation. Approximately 50% of the species seem to favor old-growth forest, and 15 species (30%) had a significantly higher occupancy in old-growth forest sites. Elevation had no significant impact on the occupancy of the majority of bird species. Although BCI has been a protected reserve for approximately 100 years, land-use legacies (i.e., forest age) continue to influence bird distribution.

scholarly journals Bird Assemblages in Second-Growth and Old-Growth Forests, Costa Rica: Perspectives From Mist Nets and Point Counts

The Auk ◽  
2001 ◽  
Vol 118 (2) ◽  
pp. 304-326 ◽  
Author(s):  
John G. Blake ◽  
Bette A. Loiselle
Keyword(s):  
Costa Rica ◽  
Community Composition ◽  
Threatened Species ◽  
Bird Species ◽  
Old Growth ◽  
La Selva ◽  
Point Counts ◽  
Old Growth Forest ◽  
Second Growth ◽  
Old Growth Forests

Abstract Second growth has replaced lowland forest in many parts of the Neotropics, providing valuable habitat for many resident and migrant bird species. Given the prevalence of such habitats and the potential benefit for conservation of biodiversity, it is important to understand patterns of diversity in second growth and old growth. Descriptions of species-distribution patterns may depend, however, on method(s) used to sample birds. We used data from mist nets and point counts to (1) describe species diversity and community composition in second-growth (young and old) and old-growth forests at La Selva Biological Station, Costa Rica; and (2) to evaluate perspectives on community composition provided by the two methods. We recorded 249 species from 39 families, including 196 species captured in mist nets (10,019 captures) and 215 recorded during point counts (15,577 observations), which represents ∼78% of the terrestrial avifauna known from La Selva (excluding accidentals and birds characteristic of aquatic or aerial habitats). There were 32 threatened species, 22 elevational migrants, and 40 latitudinal migrants. Species richness (based on rarefaction analyses of capture and count data) was greatest in the youngest site. Latitudinal migrants were particularly common in second growth; elevational migrants were present in both young and old forest, but were more important in old-growth forest. Several threatened species common in second growth were not found in old-growth forests. Trophic composition varied less among sites than did species composition. Mist nets and point counts differed in numbers and types of species detected. Counts detected more species than nets in old-growth forest, but not in young second growth. Mist nets detected 62% of the terrestrial avifauna, and point counts detected 68%. Fifty-three species were observed but not captured, and 34 species were captured but not observed. Six families were not represented by mist-net captures. Data from mist nets and point counts both support the conclusion that second-growth vegetation provides habitat for many species.

scholarly journals GEOSPATIAL ECOLOGICAL FOREST CORRIDOR MODELLING IN THE MOUNT LANTOY KEY BIODIVERSITY AREA

2019 ◽  
Vol XLII-4/W19 ◽  
pp. 347-352
Author(s):  
I. P. Quijano ◽  
M. J. L. Flores ◽  
A. B. Malaki
Keyword(s):  
Forest Cover ◽  
Species Distribution Model ◽  
Bird Species ◽  
Canopy Cover ◽  
Distribution Model ◽  
Forest Patches ◽  
Biodiversity Indicator ◽  
Ecological Corridors ◽  
Forest Corridors ◽  
The Cost

Abstract. In biodiversity conservation, ecological corridors are assumed to increase landscape-level connectivity and to enhance the viability of otherwise isolated wildlife populations. Mapping these corridors serves as a feasible method to support forest management efforts in pinpointing areas to give special attention to. Here, we assess the current forest presence in the 3,000 hectare Mt. Lantoy, Key Biodiversity Area in Argao, Cebu and present potential forest corridors that could enhance the canopy cover of the current protected area. We present a method to map the potential corridors through the identification of the forest patches obtained from the global forest cover dataset and the creation of a species distribution model for the black shama, an endemic bird species in Cebu island and a great biodiversity indicator for the area. Our ecological corridors were acquired through the sum of the cost distance rasters obtained from the weighted overlay and cost surface tools of the black shama habitat suitability model. With the obtained corridors from the study, four potential forest corridors/ extensions were identified connecting five different forest patches. These corridors have areas that range from 0.47–2.17 square kilometers, with a potential to increase the forest cover in the KBA to more than 33% after corridor modelling.

Birds in patches of old-growth ash forest, in a matrix of younger forest

1998 ◽  
Vol 4 (2) ◽  
pp. 111 ◽  
Author(s):  
Richard H. Loyn
Keyword(s):  
Forest Structure ◽  
Patch Size ◽  
Forest Birds ◽  
Old Growth ◽  
Forest Patches ◽  
Bird Abundance ◽  
Old Growth Forest ◽  
Generalized Linear Modelling ◽  
Mountain Ash ◽  
Context Variables

Birds were studied at 57 sites in Mountain Ash forests in the Central Highlands of Victoria, Australia in spring and summer 1995/96. The sites represented 41 patches of old-growth forest (up to 390 ha in size) in a matrix of regrowth mostly from severe fires in 1939 (57 years previously), with multiple sites in the four largest patches of old-growth and eight sites in 1939 regrowth. Relative bird abundance was assessed by an area-search technique. Generalized linear modelling was used to develop predictive models by regressing abundance of groups of bird species against patch size, isolation and some basic habitat and context variables. Total bird abundance (of all species combined) tended to be higher in old-growth patches than in 1939 regrowth, but not significantly. There was no trend in total abundance with patch size or isolation. Fruit-eating birds tended to be commonest in small patches. Bark-foragers and uncommon birds favoured large patches, though the latter were most common in 1939 regrowth. More variation was explained by habitat and context variables such as aspect, altitude and forest structure. Unevenaged forest structure was often associated with small patches. It was concluded that old-growth forest patches can have similar values per hectare for forest birds whether they are large or small. The regrowth forest matrix appears to protect small patches from factors which reduce densities of forest birds in small forest patches in farmland. The data support the current policy of retaining all old-growth ash forest patches. A range of factors should be considered in selecting regrowth stands of various sizes to regrow as old forest of the future, including their intrinsic potential to develop particular habitats and produce a mix of forest stuctures in the landscape.

Detecting changes in the state of reindeer pastures in northernmost Finland, 1995–2005.

Polar Record ◽  
2011 ◽  
Vol 48 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Alfred Colpaert ◽  
Jouko Kumpula
Keyword(s):  
Remote Sensing ◽  
Forest Cover ◽  
Grid Cell ◽  
The State ◽  
Ancillary Data ◽  
Old Growth ◽  
Field Methods ◽  
Old Growth Forest ◽  
Management Area ◽  
In The Beginning

ABSTRACTThe state of pastures in the Finnish reindeer management area has been monitored since 1995 using remote sensing and field inventory. The first inventory was made in 1995–1996, updated in the beginning of 2000s and repeated in 2005–2008. By comparing results from 1995–1996 and 2005–2008 we can observe clear changes in forest cover, structure and ground lichen abundance. To evaluate pasture/vegetation changes on the basis of separate classifications we have used a grid approach. By implementing a 500 by 500 m grid network and summarizing pasture classes for every grid cell we can visualize and quantify intensity of change. By comparing 1995–1996 and 2005–2008 we can see a clear decrease in the number of cells classified old growth dominated forest, and also an increase of fragmentation can be detected. With a 7.5 ha threshold the amount of old growth forest was reduced by 5%, for 20 ha the decrease was 21%. This indicates a significant change in forest landscape structure, fragmentation and reduction of reindeer winter pasture value in large areas. Pixel wise comparison showed no substantial changes in pasture areas. There is a degree of uncertainty in change detection; changes in remote sensing instrument, changes in processing software and methodology, changes in field methods and ancillary data, and obviously also bias introduced by differences between analysts. When comparing reindeer lichen biomass between 1995–1996 and 2005–2008 on the basis of field site data, the measured lichen biomass has declined in 19 out of the 20 reindeer management districts. Only one district showed slight improvement, in three districts there was a notable drop in lichen biomass, from over 1500 kg/ha to about 500 kg/ha. Also amount of arboreal lichens declined due to felling of old growth forest, confirming the findings on the grid cell level. Consequently grass, shrub and sapling stands increased as felled areas start to grow graminoids and herbs.

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