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Forest Biodiversity (forest + biodiversity)

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Life Sciences	100%

Selected Abstracts

The Potential for Species Conservation in Tropical Secondary Forests

CONSERVATION BIOLOGY, Issue 6 2009
ROBIN L. CHAZDON
especialización de hábitat; biodiversidad forestal; bosque secundario; bosque tropical; sucesión Abstract:,In the wake of widespread loss of old-growth forests throughout the tropics, secondary forests will likely play a growing role in the conservation of forest biodiversity. We considered a complex hierarchy of factors that interact in space and time to determine the conservation potential of tropical secondary forests. Beyond the characteristics of local forest patches, spatial and temporal landscape dynamics influence the establishment, species composition, and persistence of secondary forests. Prospects for conservation of old-growth species in secondary forests are maximized in regions where the ratio of secondary to old-growth forest area is relatively low, older secondary forests have persisted, anthropogenic disturbance after abandonment is relatively low, seed-dispersing fauna are present, and old-growth forests are close to abandoned sites. The conservation value of a secondary forest is expected to increase over time, as species arriving from remaining old-growth forest patches accumulate. Many studies are poorly replicated, which limits robust assessments of the number and abundance of old-growth species present in secondary forests. Older secondary forests are not often studied and few long-term studies are conducted in secondary forests. Available data indicate that both old-growth and second-growth forests are important to the persistence of forest species in tropical, human-modified landscapes. Resumen:,A raíz de la pérdida generalizada de los bosques maduros en el trópico, los bosques secundarios probablemente jugarán un mayor papel en la conservación de la biodiversidad forestal. Consideramos una jerarquía compleja de factores que interactúan en el espacio y tiempo para determinar el potencial de conservación de los bosques tropicales secundarios. Más allá de las características de los fragmentos de bosque locales, la dinámica espacial y temporal del paisaje influye en el establecimiento, la composición de especies y la persistencia de bosques secundarios. Los prospectos para la conservación de especies primarias en los bosques secundarios se maximizan en regiones donde la proporción de superficie de bosque maduro-bosque secundario es relativamente baja, los bosques secundarios más viejos han persistido, la perturbación antropogénica después del abandono es relativamente baja, hay presencia de fauna dispersora de semillas y donde hay bosques primarios cerca de sitios abandonados. Se espera que el valor de conservación de un bosque secundario incremente en el tiempo, a medida que se acumulan especies provenientes de los fragmentos de bosque primario remanentes. Muchos estudios están pobremente replicados, lo que impide evaluaciones robustas del número y abundancia de especies primarias presentes en bosques secundarios. Los bosques secundarios más viejos generalmente no son estudiados y son pocos los estudios a largo plazo en bosques secundarios. Los datos disponibles indican que tanto los bosques primarios como los secundarios son importantes para la persistencia de especies forestales en paisajes tropicales modificados por humanos. [source]

Species,area relationships of red-listed species in old boreal forests: a large-scale data analysis

DIVERSITY AND DISTRIBUTIONS, Issue 5 2009
Olli-Pekka Tikkanen
Abstract Aim, Species,area relationships are often applied, but not generally approved, to guide practical conservation planning. The specific species group analysed may affect their applicability. We asked if species,area curves constructed from extensive databases of various sectors of natural resource administration can provide insights into large-scale conservation of boreal forest biodiversity if the analyses are restricted only to red-listed species. Location, Finland, northern Europe. Methods, Our data included 12,645 records of 219 red-listed Coleoptera and Fungi from the whole of Finland. The forest data also covered the entire country, 202,761 km2. The units of species,area analyses were 224 municipalities where the red-listed forest species have been observed. We performed a hierarchical partitioning analysis to reveal the relative importance of different potential explanatory variables. Based on the results, for all red-listed species, species associated with coniferous trees and for Fungi, the area of economically over-aged forests explained the best the variation in data. For species associated with deciduous trees and Coleoptera, the forest area explained better variation in data than the area of old forests. In the subsequent log,log species,area regression analyses, we used the best variables as the explanatory variable for each species group. Results, There was a strong relationship between the number of all red-listed species and the area of old forests remaining, with a z -value of 0.45. The area explained better the number of species associated with conifer trees and Fungi than the number of species associated with deciduous trees and Coleoptera. Main conclusions, The high z -values of species,area curves indicate that the remaining old-growth patches constitute a real archipelago for the conifer-associated red-listed species, since lower values had been expected if the surrounding habitat matrix were a suitable habitat for the species analysed. [source]

Blister rust and western forest biodiversity: ecology, values and outlook for white pines

FOREST PATHOLOGY, Issue 3-4 2010
D. F. Tomback
Summary Eight white pine species are widely distributed among the forests of western Canada and the United States. The different forest communities with these species contribute biodiversity to the western landscape. The trees themselves provide various ecosystem services, including wildlife habitat and watershed protection. White pine communities range in elevation from lower to upper treeline, in successional stage from seral to climax, and in stand type from krummholz to closed-canopy forest. Many white pine species are moderately to strongly fire-dependent for regeneration; several species are extreme stress tolerators and persistent on harsh sites. Among the white pines are the oldest-living trees, the world's largest pines, species dependent on birds for seed dispersal, species important for grizzly bear habitat and species of high commercial timber value. The principal threats to white pine populations are blister rust (Cronartium ribicola, pathogen), fire suppression, succession, mountain pine beetle and climate change. Severe population declines in several white pine species are attributed to losses caused by these factors acting either alone or together, and sometimes in concert with logging and other land-use changes. The importance and particular interactions of these threats vary by region and species. For example, many northern and western populations of whitebark pine are seriously declining from a combination of mountain pine beetle outbreaks and severe blister rust infestations. As whitebark pines provide many keystone services on high-elevation sites, their loss would impact forest composition and structure, succession, biodiversity, and ecosystem services. Although there are serious challenges to science-based management and conservation (especially in remote American wilderness areas), prompt and effective intervention promoting regeneration of blister rust-resistant white pines could mitigate these severe impacts. [source]

Population trends of widespread woodland birds in Europe

IBIS, Issue 2007
RICHARD D. GREGORY
We explore population trends of widespread and common woodland birds using data from an extensive European network of ornithologists for the period 1980,2003. We show considerable differences exist in the European trends of species according to the broad habitat they occupy and the degree to which they specialize in habitat use. On average, common forest birds are in shallow decline at a European scale; common forest birds declined by 13%, and common forest specialists by 18%, from 1980 to 2003. In comparison, populations of common specialists of farmland have declined moderately, falling on average by 28% from 1980 to 2003. These patterns contrast with that shown by generalist species whose populations have been roughly stable over the same period, their overall index increasing by 3%. There was some evidence of regional variation in the population trends of these common forest species. The most obvious pattern was the greater stability of population trends in Eastern Europe compared with other regions considered. Among common forest birds, long-distance migrants and residents have on average declined most strongly, whereas short-distance migrants have been largely stable, or have increased. There was some evidence to suggest that ground- or low-nesting species have declined more strongly on average, as have forest birds with invertebrate diets. Formal analysis of the species trends confirmed the influence of habitat use, habitat specialization and nest-site; the effects of region and migration strategy were less clear-cut. There was also evidence to show that year-to-year variation in individual species trends at a European scale was influenced by cold winter weather in a small number of species. We recommend that the species trend information provided by the new pan-European scheme should be used alongside existing mechanisms to review the conservation status of European birds. The analysis also allows us to reappraise the role of common forest bird populations as a potential barometer of wider forest health. The new indicator appears to be a useful indicator of the state of widespread European forest birds and might prove to be a useful surrogate for trends in forest biodiversity and forest health, but more work is likely to be needed to understand the interaction between bird populations and their drivers in forest. [source]

Vertebrate Fauna Recolonization of Restored Bauxite Mines,Key Findings from Almost 30 Years of Monitoring and Research

RESTORATION ECOLOGY, Issue 2007
Owen G. Nichols
Abstract Studies into the processes of vertebrate fauna colonization of Alcoa's restored bauxite mines began around 1975. This recognized the key role of vertebrate fauna in jarrah forest ecosystem processes, and also the fact that some species were rare, so priority was given to determining their status in unmined forest, and promoting their return to restored areas following mining. Long-term studies have since taken place on mammals, birds, and reptiles both in unmined forest and in restored areas of varying ages and techniques. Mammal recolonization varies between species depending on species' food and shelter requirements and their distribution and abundance in the surrounding forest. Birds rapidly recolonize and 95% of species have been recorded in restoration. Bird community structure changes with restoration type and age, and in current restoration, it is similar to that of unmined forest by the age of 10 years. Studies on reptiles have shown that 21 of 24 species have recolonized. The remaining three include one legless lizard and two snakes, all of which feed on small vertebrates (e.g., skinks) and require shelter in the form of logs, stumps, and coarse woody debris. Some other reptile species consistently occur in restoration in lower densities than in unmined forest, and current studies are investigating the causes of this. Together, studies on these three vertebrate fauna groups have provided valuable, complementary information on their habitat requirements, and the extent to which Alcoa's restoration program has been successful in reestablishing this important component of the jarrah forest's biodiversity. [source]