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1.
Víctor Arroyo-Rodríguez Romeo A. Saldaña-Vázquez Lenore Fahrig Bráulio A. Santos 《Ecological Research》2017,32(1):81-88
Forest fragmentation is considered by many to be a primary cause of the current biodiversity crisis. The underlying mechanisms are poorly known, but a potentially important one is associated with altered thermal conditions within the remaining forest patches, especially at forest edges. Yet, large uncertainty remains about the effect of fragmentation on forest temperature, as it is unclear whether temperature decreases from forest edge to forest interior, and whether this local gradient scales up to an effect of fragmentation (landscape attribute) on temperature. We calculated the effect size (correlation coefficient) of distance from forest edge on air temperature, and tested for differences among forest types surrounded by different matrices using meta-analysis techniques. We found a negative edge-interior temperature gradient, but correlation coefficients were highly variable, and significant only for temperate and tropical forests surrounded by a highly contrasting open matrix. Nevertheless, it is unclear if these local-scale changes in temperature can be scaled up to an effect of fragmentation on temperature. Although it may be valid when considering “fragmentation” as forest loss only, the landscape-scale inference is not so clear when we consider the second aspect of fragmentation, where a given amount of forest is divided into a large number of small patches (fragmentation per se). Therefore, care is needed when assuming that fragmentation changes forest temperature, as thermal changes at forest edges depend on forest type and matrix composition, and it is still uncertain if this local gradient can be scaled up to the landscape. 相似文献
2.
《Biomass》1982,2(1):29-41
In any consideration of the use of biomass for energy in Canada and its effect on forest management practices, it should be understood that a major change in the energy system is involved. There will be a change from a highly organised production and delivery system controlled from outside the country's borders to production and delivery systems which are highly localised within forest regions within Canada and where the investments and the benefits accruing from them remain within the localities.Because of the highly localised and regional aspects of the production of energy from biomass it is not realistic to consider it on a Canada-wide basis. On a macroscale, Canada has ample biomass over and above conventional uses for energy purposes but locally it can be in short supply. For this reason availability of biomass in sufficient quantity and at an acceptable cost must be considered on a site-specific basis. 相似文献
3.
Have we been successful? Monitoring horizontal forest complexity for forest restoration projects
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Forest management today often seeks to restore ecological integrity and enhance human well‐being by increasing forest complexity, resilience, and functionality. However, effective and financially expedient monitoring of forest complexity is challenging. In this study, we developed a practical and inexpensive technique to measure horizontal forest complexity. This monitoring method uses intuitively understandable data (imagery) and facilitates stakeholder participation in the adaptive management process within collaborative projects. We used this technique to determine if current restoration projects are successfully achieving their spatial restoration goals. We focused on the Colorado Front Range Landscape Restoration Initiative (CFRLRI) as a representative of the typical collaborative restoration projects underway in formerly fire‐dependent dry conifer forests. The developed monitoring method is practical and cost‐effective by using free aerial imagery to map, quantify, and analyze the distribution of canopy cover pre‐ and post‐treatment. We found the CFRLRI has successfully reduced canopy cover (from 44 to 26% on average) and increased some aspects of horizontal forest complexity. The application of these monitoring techniques has allowed the CFRLRI collaborative group to objectively quantify changes to horizontal forest complexity, and has facilitated stakeholder communication about forest spatial patterns. These methods could be adapted for use by other similar forest restoration projects around the world by utilizing increasingly available satellite or aerial imagery. 相似文献
4.
Andrew M. Liebhold 《Insect Science》2005,12(5):399-400
Forests have long been recognized as excellent model systems for studying insect ecology. The fact that many forests' ecosystems still function in a semi-natural state, with little influence from human disturbance, provides unique opportunities for understanding co-evolved community and population processes. Unfortunately the structural complexity of forests and the sheer size of trees often pose formidable problems when attempting to sample insects in forests. As such, any scientist embarking on a study of forest insect ecology would be well-advised to carefullv plan their sampling efforts. 相似文献
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6.
Agricultural practices lead to losses of natural resources and biodiversity. Maintaining forests alongside streams (riparian forest strips) has been used as a mechanism to minimize the impact of clearing for agriculture on biodiversity. To test the contribution of riparian forest strips to conserve biodiversity in production landscapes, we selected bats as a biodiversity model system and examined two dimensions of diversity: taxonomic and functional. We compared bat diversity and composition in forest, with and without stream habitat, and in narrow forest riparian strips surrounded by areas cleared for agriculture. We tested the hypothesis that riparian forest strips provide potential conservation value by providing habitat and serving as movement corridors for forest bat species. Riparian forest strips maintained 75% of the bat species registered in forested habitats. We found assemblage in sites with riparian forest strips were dominated by a few species with high abundance and included several species with low abundance. Bat species assemblage was more similar between sites with streams than between those sites to forests without stream habitat. These results highlight the importance of stream habitat in predicting presence of bat species. We registered similar number of guilds between forest sites and riparian forest strips sites. Relative to matrix habitats, stream and edge habitats in riparian forest strips sites were functionally more diverse, supporting our hypothesis about the potential conservation value of riparian forest strips. Results from this study suggest that maintaining riparian forest strips within cleared areas for agricultural areas helps conserve the taxonomic and functional diversity of bats. Also, it provides basic data to evaluate the efficacy of maintaining these landscape features for mitigating impacts of agricultural development on biodiversity. However, we caution that riparian forest strips alone are not sufficient for biodiversity maintenance; their value depends on maintenance of larger forest areas in their vicinity. 相似文献
7.
Yukihiro Morimoto John B. Njoroge Akihiro Nakamura Takeshi Sasaki Yutaka Chihara 《Landscape and Ecological Engineering》2006,2(2):119-127
The forest-restoration project of EXPO ’70 Commemorative Park, Japan, is an epoch-making attempt to restore a nature-oriented forest park in an urban area in which large-scale land reclamation had occurred. The objective of this paper is to review the concept, planning, and design, and the outcome so far, and discuss current aspects of creating a core natural habitat in the city of Osaka. Innovative planning policy and design methods have been used for construction of the forest-restoration project of EXPO Park. Unexpected troubles have occurred, however. After approximately 10 years severe effects of poor drainage and soil compaction on the establishment of the forest have been revealed by intensive monitoring. Partial redevelopment and soil-amendment work has therefore been conducted. These improvements seemed to have resulted in “a self-sustaining forest”, the original objective of the planning policy. After approximately 25 years, however, a second intensive monitoring program has revealed that the status of nature restoration is generally favorable in quantity but not in structure of forest communities or biodiversity. The major issues identified are excessive tree density with a single foliage layer caused by the single generation of immature forest stand, and ecological isolation from the source of nature. The EXPO forest is currently in the “Second Generation” stage; this involves management, including artificial gap regeneration, and soil seed bank introduction, with careful monitoring. The project is expected to be an ideal example of a core habitat of nature-oriented forest in urban areas achieved by adaptive management. 相似文献
8.
Petra Lindemann-Matthies Dominique Keller Xuefei Li Bernhard Schmid 《Journal of Plant Ecology》2014,7(1):1
Aims Despite the current interest in services provided by ecosystems and the role of biodiversity, the relationship among human attitudes, biodiversity and ecosystem services has hardly been investigated. Moreover, few studies have examined attitudes toward nature in cross-cultural comparisons. This study investigates the attitudes of Chinese and Swiss people, both environmental experts and laypersons, toward forest biodiversity and ecosystem services.Methods Overall, 640 people in China and Switzerland were interviewed with the help of a standardized questionnaire. In each country, the study population was equally divided into an urban (80 city dwellers and 80 environmental science students) and a rural (80 forest visitors and 80 farmers) study group. The 15-minute interviews took place in the cities of Beijing and Zurich and in the rural forested areas of Dujiangyan, Sichuan Province and Lake Sempach, canton Lucerne. Attitudes toward forest biodiversity were investigated with the help of color photographs that depicted both monocultures and species-rich forests typical for China and Switzerland. Attitudes toward ecosystem services were investigated with the help of 13 statements on provisioning, regulating, cultural and supporting services of forests.Important findings On average, Chinese participants showed no strong preferences for biodiversity, whereas the Swiss clearly preferred species-rich forests over monocultures. However, Chinese environmental science students did prefer species-rich forests and attributed to them a higher conservation value because of their higher biodiversity. Although there were no strong preferences for Chinese versus Swiss forests, all participants correctly answered that Chinese forests are more species rich in terms of plants and animals and thus found them less boring and more interesting, but also less managed, than Swiss forests. All participants highly valued the ecosystem services provided by forests; especially the regulating and supporting ones. Environmental science students and farmers placed more importance on the provisioning services, whereas city dwellers and forest visitors emphasized more on the regulating services. The disjuncture between the high ecological quality of species-rich forests and their low attractiveness to Chinese study participants points to a potential conflict between conservation policies and the public's preferences. A better communication of ecosystem services provided by forest biodiversity to the public might change these preferences in favor of ecological quality, as already observed among Chinese environmental science students. 相似文献
9.
Are habitat islands islands? Woodliving beetles (Coleoptera) in deciduous forest fragments in boreal forest 总被引:4,自引:0,他引:4
Stefan Ås 《Ecography》1993,16(3):219-228
Modern forestry has changed the fire dynamics in the boreal forest and as a result the size and number of deciduous forest patches have been reduced as well as the number of deciduous trees within the coniferous forest This has exaggerated the insularity of deciduous forest patches within the boreal coniferous forest zone In this paper I examine whether the diversity of beetles living in dead stems of deciduous trees follows the relationship with patch area to be predicted from island biogeographic theory, and to what extent the species assemblages differ between large and small patches and single deciduous trees within managed coniferous forests Three larger patches of deciduous forest (>120 ha) arisen as successions after forest fires in the late 1880's are compared with 6 small (<20 ha) patches of similar origin No difference in diversity could be detected between large and small patches A statistically significant difference between assembly composition was detected using matrix regression between a matrix of observed assembly similarities and a hypothetical similarity matrix based on the type of area in which the plot was situated (large- small or matrix) Finally I examined the distribution of the 56 most common beetle species over the habitat types investigated Thirty four species did not show any Significant habitat preference, 12 were found more often in clear-cut areas than expected 5 were over-represented in small patches, and 4 in large areas My explanation to this apparent lack of insularity effects is the relative recent commencement of intensive forestry in these areas and the fact that the matrix is of rather high quality that is inhabitable for numerous beetle species Thus the patches may be viewed as incipient islands still exchanging biota with their surroundings 相似文献
10.
C. Blasi M. Marchetti U. Chiavetta M. Aleffi P. Audisio M. M. Azzella 《Plant biosystems》2013,147(1):160-170
Abstract The most commonly used old‐growth forest indicators are structural attributes; nevertheless, they do not necessarily represent the biodiversity value of old‐growth forests. The aim of this study is to analyse the relationships between species richness data of different taxa and structural indicators of old‐growth and to identify taxonomic/functional groups, species and structural attributes that may be used as indicators of old‐growth. To achieve this goal we sampled forest structure, vascular plants, lichens, bryophytes, fungi, saproxylic beetles and birds in mature and old‐growth stands in southern Italy. We calculated Spearman’s correlation coefficients between species richness data and structural attributes. Analyses of indicator species, co‐occurrences and two‐way clusters were performed on the multi‐taxonomic list. The group of vascular plants most significantly correlated with other groups in terms of species richness; furthermore, it displays the highest proportion of between‐group co‐occurrences. The resulting multi‐taxonomic list of potential indicators may serve as an effective means of detecting and monitoring forest ecosystems; however, for this goal, structure‐based indicators, such as forest structural attributes and vascular plant species composition, are of primary importance. 相似文献
11.
When a habitat becomes fragmented and surrounded by another habitat this generally causes an increase in predation pressure at habitat transitions, often referred to as an edge effect. Edge effect in the form of enhanced nest predation intensities is one of the most cited explanations for bird population declines in fragmented landscapes. Here, we report results from a nest predation experiment conducted in a tropical montane forest landscape in the Uzungwa Mts., Tanzania. Using artificial nests with chicken eggs, we determined predation rates across a fragmentation gradient. The proportion of indigenous forest in four landscapes used in the study were 0.29, 0.58, 0.75 to 1.0. Nest predation intensities on artificial nests were about 19% higher inside intact forest than at edges in fragmented forest landscapes. Furthermore, predation intensities were relatively constant across a forest fragmentation gradient. Our results thus challenge the applicability and generality of the edge effect, derived from studies almost exclusively conducted in temperate regions rather than tropical forest ecosystems. Nest predation levels differences between tropical montane forest and that reported in other forest ecosystems are discussed. 相似文献
12.
Ecological restoration is increasingly called on to provide ecosystem services (ES) valuable to humans, as well as to benefit biodiversity and improve wildlife habitat. Where mechanisms to pay for ES exist, they may serve as incentives to embark on habitat restoration projects. We evaluated the potential of newly established carbon markets in the United States to incentivize afforestation along riparian corridors, by comparing the income earnable by carbon offset credits with the costs of planting, maintaining, and registering such a restoration project in California. We used a 20‐year chronosequence of riparian forest sites along the Sacramento River as our model project. We found that carbon credits can repay more than 100% of costs after two decades of regrowth, if sufficient effort is put into sampling intensity in the first post‐restoration decade. However, carbon credits alone are unlikely to entice landowners currently engaged in agricultural activities to switch from farming crops to farming habitat. 相似文献
13.
We studied the distribution of millipedes in a forest interior-forest edge-grassland habitat complex in the Hajdúság Landscape Protection Area (NE Hungary). The habitat types were as follows: (1) lowland oak forest, (2) forest edge with increased ground vegetation and shrub cover, and (3) mesophilous grassland. We collected millipedes by litter and soil sifting. There were overall 30 sifted litter and soil samples: 3 habitat types × 2 replicates × 5 soil and litter samples per habitats. We collected 9 millipede species; the most abundant species was Glomeris
tetrasticha, which was the most abundant species in the forest edge as well. The most abundant species in the forest interior was Kryphioiulus
occultus, while the most abundant species in the grassland was Megaphyllum
unilineatum. Our result showed that the number of millipede species was significantly lower in the grassland than in the forest or in the edge, however there were no significant difference in the number of species between the forest interior and the forest edge. We found significantly the highest number of millipede individuals in the forest edge. There were differences in the composition of the millipede assemblages of the three habitats. The results of the DCCA showed that forest edge and forest interior habitats were clearly separated from the grassland habitats. The forest edge habitat was characterized by high air temperature, high soil moisture, high soil pH, high soil enzyme activity, high shrub cover and low canopy cover. The IndVal and the DCCA methods revealed the following character species of the forest edge habitats: Glomeris
tetrasticha and Leptoiulus
cibdellus. Changes in millipede abundance and composition were highly correlated with the vegetation structure. 相似文献
14.
Berryman AA 《Trends in ecology & evolution》1996,11(1):28-32
Hypotheses for the causes of regular cycles in populations of forest Lepidoptera have invoked pathogen-insect or foliage-insect interactions. However, the available data suggest that forest caterpillar cycles are more likely to be the result of interactions with insect parasitoids, an old argument that seems to have been neglected in recent years. 相似文献
15.
Groover AT 《Trends in plant science》2007,12(6):234-238
Forest biotechnology has been increasingly associated with wood production using plantation forestry, and has stressed applications that use pedigreed material and transgenic trees. Reasons for this emphasis include limitations of available technologies to conform to underlying genetic features of undomesticated forest tree populations. More recently, genomic technologies have rapidly begun to expand the scope of forest biotechnology. Genomic technologies are well suited to describe and make use of the abundant genetic variation present in undomesticated forest tree populations. Genomics thus enables new research and applications for conservation and management of natural forests, and is a primary technological driver for new research addressing the use of forests trees for carbon sequestration, biofuels feedstocks, and other 'green' applications. 相似文献
16.
Forest expansion or fragmentation? Discriminating forest fragments from natural forest patches through patch structure and spatial context metrics
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Ana Luiza Leichter Matte Sandra Cristina Müller Fernando Gertum Becker 《Austral ecology》2015,40(1):21-31
In forest–grassland mosaics, patches can result from two processes: forest expansion over grassy ecosystems and forest fragmentation. We tested the hypothesis that patches produced by these processes differed in structure and spatial context in a forest–grassland mosaic in the southern Brazilian highlands. We compared a present‐day land cover map with a past vegetation map to identify natural forest patches and forest fragments. Patches were described according to structure (size, core area and shape metrics) and spatial context (distance from roads and urban areas, edge contrast). Principal component analyses were used to examine gradients of patch types, and differences were tested by analysis of variance with randomization test. We found 878 natural patches and 214 fragments. Natural forest patches, riparian forest patches and forest fragments differed in structure and spatial context. In comparison to natural forest patches, fragments tend to be larger, with larger core areas, and more irregular and complex in shape. Fragments are situated in a different spatial context, tending to be closer to roads and urban areas and to present higher edge contrast. Riparian natural forest patches are similar to natural forest patches, except for shape. The smaller area and regular shape of natural patches probably result from the mechanisms involved in nucleus formation in the grassland matrix and from current grassland management. Natural patches are less exposed to some anthropogenic stresses, since most of them remain in a native grassland matrix context. Our results show that inferring process from pattern is not trivial, because different processes – forest expansion and forest fragmentation – may lead to either distinct or similar patterns of patch shape and spatial context. Studying patch structure and spatial context may then provide further insight into understanding changes in vegetation pattern at landscape scale, and in disentangling the effects of concurrent processes. 相似文献
17.
Sarah Rowley Adrià López-Baucells Ricardo Rocha Paulo E. D. Bobrowiec Christoph F. J. Meyer 《Restoration Ecology》2024,32(3):e14093
Passive forest restoration can buffer the effects of habitat loss on biodiversity. We acoustically surveyed aerial insectivorous bats in a whole-ecosystem fragmentation experiment in the Brazilian Amazon over a 2-year period, across 33 sites, comprising continuous old-growth forest, remnant fragments, and regenerating secondary forest matrix. We analyzed the activity of 10 species/sonotypes to investigate occupancy across habitat types and responses to fragment size and interior-edge-matrix (IEM) disturbance gradients. Employing a multiscale approach, we investigated guild (edge foragers, forest specialists, flexible forest foragers, and open space specialists) and species-level responses to vegetation structure and forest cover, edge, and patch density across six spatial scales (0.5–3 km). We found species-specific habitat occupancy patterns and nuanced responses to fragment size and the IEM disturbance gradient. For example, Furipterus horrens had lower activity in secondary forest sites and the interior and edge of the smallest fragments (1 and 10 ha) compared to continuous forest, and only two species (Pteronotus spp.) showed no habitat preference and no significant responses across the IEM and fragment size gradients. Only the Molossus sonotype responded negatively to vegetation structure. We uncovered no negative influence of forest cover or edge density at guild or species-level. Our results indicate that reforestation can buffer the negative effects of fragmentation and although these effects can still be detected in some species, generally aerial insectivorous bats appear to be in recovery after 30 years of passive forest restoration. Our findings reinforce the need to protect regenerating forests while conserving vast expanses of old-growth forest. 相似文献
18.
van Oijen AM 《Nature chemical biology》2008,4(8):440-443
The development of single-molecule tools has significantly impacted the way we think about biochemical processes. Watching a single protein in action allows us to observe kinetic details and rare subpopulations that are hidden in ensemble-averaging techniques. I will discuss here the pros and cons of the single-molecule approach in studying ligand binding in macromolecular systems and how these techniques can be applied to characterize the behavior of large multicomponent biochemical systems. 相似文献
19.
Forest fragments embedded within agricultural landscapes have the potential to provide a “forest reset effect” by mitigating
agricultural effects on water quality, and acting as refugia and conservation reserves for aquatic species. We investigated
the ability of forest fragments to reset agricultural effects using four catchments in the South Island, New Zealand. Two
catchments were dominated by agricultural activities, but each had an isolated forest fragment in the lower valley, and two
catchments had continuous riparian forest along the valley floor. Riffles sampled in continuous forest were generally deeper
than those in agricultural and forest fragments, and not surprisingly streams in forest fragments and continuous forest received
less light than those in agricultural land. All sites had circum-neutral pH, but both conductivity and temperature were significantly
lower at continuous forest sites than agricultural and forest fragment sites. Taxonomic richness, Margalef’s index and numbers
of Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa were significantly higher in continuous forest than at forest fragment
sites, but overall invertebrate densities did not differ between fragments and continuous forest. Several taxa were abundant
at agricultural and forest fragment sites, but absent or at low densities in continuous forest. They included the blackfly
Austrosimulium spp. and two caddisflies Pycnocentrodes sp. and Hydrobiosis parumbripennis. Conversely, the mayflies Austroclima sp. and Coloburiscus humeralis and the blepharicerid Neocurupira chiltoni were either restricted to continuous forest, or abundant in continuous forest but rare in agricultural and forest fragments.
An ordination of communities separated those in agricultural and continuous forest sites, but communities at forest fragment
sites were clustered among the agricultural sites. In this study forest fragments of 5–7 ha, located in the lower reaches
of the catchment did not mitigate the negative upstream effects of agriculture on stream functioning. Fragment size (or riparian
forest length), riparian forest width and vegetation type, and fragment location in the catchment may have critical roles
in enabling forest fragments to reset the negative impacts of agriculture. Determining these characteristics of fragments
has important consequences for stream remediation. 相似文献
20.
Jaime García‐Moreno José Maria Cardoso da Silva 《Studies on Neotropical Fauna and Environment》2013,48(3):164-173
Very few South American avian superspecies or species groups are composed of both forest and non‐forest taxa. The genus Lepidocolaptes comprises 8–9 species of woodcreepers, most of which are forest birds, but two species, L. angustirostris and L. souleyetii, inhabit open vegetations. Therefore, this genus should play an important role in the discussion about the relationships between forest and non‐forest South American avifaunas. Nucleotide sequences from two mitochondrial genes, cytochrome b and ND2, suggest that: (i) L. fuscus should be removed from the genus since its association with other members of this genus is poorly supported. This view has been pointed out also by morphological and behavioural data; (ii) the phylogenetic position of the open‐vegetation species within the Lepidocolaptes radiation indicate that the split between forest and non‐forest elements within this genus took place as recently as two million years ago. This result suggests that the evolutionary relationships between forest and non‐forest biotas in South America may have been more dynamic than previously thought. 相似文献