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1.
While pesticides help to effectively control crop pests, their collateral effects often harm the environment. On the French island of Reunion in the Indian Ocean, over 75% of the pesticides used are herbicides and they are regularly detected in water. Agri-environmental models and pesticide risk indicators can be used to predict and to help pesticide users to reduce environmental impacts. However, while the complexity of models often limits their use to the field of research, pesticide risk indicators, which are easier to implement, do not explicitly identify the technical levers that farmers can act upon to limit such transfers on their scale of action (the field). The aim of this article is to contribute to developing a decision support tool to guide farmers in implementing relevant practices regarding the reduction of pesticide transfers. In this article, we propose a methodology based on classification and regression trees. We applied our methodology to a pesticide risk indicator (I-PHY indicator) for identifying the importance of the variables, their interactions and relative weight in contributing to the score of the indicator. We applied our methodology to the assessment of transfer risks linked to the use of 20 herbicides applied to all soils in Reunion and according to different climate, plot management and product application scenarios (4096 scenarios tested). We constructed regression trees which identified, for each herbicide on each soil type, the contribution made by each input variable to the construction of the indicator score. The tree is represented graphically, and this aids exploration and understanding. The 20 herbicides were divided into 3 groups that differed through the main contributing variable to the indicator score. These variables were all technical levers available to farmers to limit transfer risks. These trees then become decision support tools specific to each pesticide user, enabling them to take appropriate decisions with a view to reducing pesticide environmental impacts. 相似文献
2.
Ian K. Dawson Manuel R. Guariguata Judy Loo John C. Weber Ard Lengkeek David Bush Jonathan Cornelius Luigi Guarino Roeland Kindt Calleb Orwa Joanne Russell Ramni Jamnadass 《Biodiversity and Conservation》2013,22(2):301-324
Smallholders’ agroforests may be valuable for conserving tropical trees through three main mechanisms. First, trees planted and/or retained by farmers in agricultural landscapes where wild stands were once found may be circa situm reservoirs of biodiversity. Second, farmland trees may support conservation in situ by providing an alternative source of product to reduce extraction from forest, and by acting as ‘corridors’ or ‘stepping stones’ that connect fragmented wild stands. Third, the additional value that planting assigns to trees may result in greater interest in including them in seed collections, field trials and field ‘genebanks’ that support ex situ conservation. Here, we critically review the evidence for these mechanisms, and highlight areas for research and for intervention so that agroforestry practices can better support conservation in each setting, with an emphasis on often neglected genetic-level considerations. Based on current global challenges to diversity, conservation will need to rely increasingly on a smallholder-farm circa situm approach, but concerns on long-term effectiveness need to be properly quantified and addressed. Connectivity between widely dispersed, low density trees in agricultural landscapes is an important factor determining the success of the circa situm approach, while improving farmers’ access to a diversity of tree germplasm that they are interested in planting is required. The circumstances in which agroforestry plantings can support in situ conservation need to be better defined, and research on the stability of active tree seed collections (how long are species and populations retained in them?) as ex situ reservoirs of biodiversity is needed. 相似文献
3.
The role of local knowledge in determining shade composition of multistrata coffee systems in Chiapas,Mexico 总被引:2,自引:0,他引:2
Lorena Soto-Pinto Víctor Villalvazo-López Guillermo Jiménez-Ferrer Neptalí Ramírez-Marcial Guillermo Montoya Fergus L. Sinclair 《Biodiversity and Conservation》2007,16(2):419-436
This research explores interactions between farmers’ knowledge and socioeconomic circumstances and the floristic composition
of multistrata coffee plantations in Chiapas, Mexico. Interviews with 24 individual farmers with accompanying vegetation transects
and two community level participatory workshops were carried out. The frequency, density, dominance, utility and importance
value for all tree species surveyed were obtained. Farmers were grouped by cluster analysis on the basis of their land area,
time producing coffee and the age of their coffee farms but the dominant shade species in their coffee plantations was not
influenced by socioeconomic status (p<0.05). A total of 74 shade species were recorded and classified as temporary, suitable, or unsuitable as shade species by
farmers, based on attributes such as leaf phenology, foliage density, crown shape and the amount and timing of litter decomposition,
as well as their overall impact on coffee yield. Principal component and cluster analysis using these attributes confirmed
the consistency of the farmers’ classification system. A group of preferred species was identified, but less than half the
trees recorded on farms were of these species, showing that farmers retained a wide range of trees and shrubs in their plantations,
taking into account not only commercial interests but also their contribution to ecosystem functions. Farmers harnessed the
forces of secondary succession by retaining pioneers as temporary shade, knowing that they would naturally be succeeded, while
at the same time promoting and tolerating other longer living native species that they considered more suitable as coffee
shade. Managing diverse secondary succession instead of establishing monospecific shade was an efficient way for farmers to
achieve acceptable coffee yields while contributing to biodiversity and landscape conservation that could allow them access
to niche markets. 相似文献
4.
5.
陕北农民对退耕还林的意愿评价 总被引:10,自引:0,他引:10
为了解生态修复政策对陕北地区社会经济的影响,2007年通过参与性农户调查方法,研究退耕还林项目对陕北居民生计的影响以及由于生态项目实施引起的农民态度的变化.结果表明:农民接受退耕还林补偿政策,但只有极少数人乐意植树(8.9%)、种草(2.2%). 尽管19.1%的农户表示他们的生计受到了项目的负面影响,63.8%的农户表示支持退耕还林项目,但是高达37.2%的农户表示项目结束后会再次垦荒种粮.由此可见,退耕还林项目恢复的植被在项目结束后有可能被重新开垦为农田,该项目获得的环境成果面临被再次破坏的风险.因此,给予合理的补偿来减少农民经济损失、通过技术进步提高单位土地面积产出、通过技术培训使农村剩余劳动力转移出来是环境修复项目成功的重要保证. 相似文献
6.
Sophie Graefe Lennart Flavio Meyer-Sand Katja Chauvette Issaka Abdulai Laurence Jassogne Philippe Vaast Richard Asare 《Human ecology: an interdisciplinary journal》2017,45(3):321-332
Shade trees are an integral part of most cocoa growing systems across the world. This study assesses farmers’ local knowledge of shade trees at two locations in Ghana with different climatic conditions and vulnerability to climate change. Akumadan is located in the northern dry part of the cocoa belt representing marginal conditions for cocoa cultivation, whereas Asankragua is located in the southern wet part, more ecologically favorable for cocoa cultivation. Inventories were conducted to assess the abundance of species, their structural characteristics and benefits to cocoa systems. Results show that cocoa farmers have detailed knowledge on the functions of shade trees in cocoa systems and prefer species that provide specific needs according to the location. However, abundance of species in a location does not necessary translate into beneficial impacts on cocoa productivity. In the drier part of the cocoa belt, income diversification through shade trees is an adaptation strategy to the increasingly marginal conditions for cocoa production, which has led to the high proportion of fruit trees among the most abundant species. In contrast, farmers in the southern part of the cocoa belt select shade trees for their high cocoa compatibility. Adaptation strategies for cocoa farmers should therefore promote species that best accommodate farmers’ economic, agronomic and environmental needs. 相似文献
7.
A. Allan Degen Luma Nidhi Pandey Michael Kam Shambhu B. Pandey Chet R. Upreti Netra P. Osti 《Human ecology: an interdisciplinary journal》2010,38(5):625-637
More than 50% of Nepal’s population lives in the hill regions, usually with small land holdings, and over 60% are considered
below the poverty line. Livestock, and particularly goats, provide these small-scale farmers with about 55% of their on-farm
income. We studied goat production in Katteldanda, a mid-hill village of 78 households, mainly Brahmins, in Ghorka District.
Subsistence farmers raise six or seven goats and one or two buffalo, and cultivate mainly maize, millet and rice. Tree fodder
constituted about 70% of dry matter intake of goats for large parts of the year and was collected by lopping branches from
trees on upland, rain-watered, private terraces (bari) near the household compound. Local farmers ranked the fodder trees they considered best and we measured the actual fodder
they offered to goats. In addition, we evaluated and ranked 23 fodder species on the basis of laboratory in vitro nutritional
and metabolizable energy yields. Using a Mantel test, a significant correlation was found between what the farmers thought
was best fodder and fodder offered to goats (Mantel r = 0.398; P = 0.037) but non-significant correlations were found between either what the farmers thought was best fodder or fodder offered
to goats and laboratory rankings (Mantel r = −0.027; P = 0.49 and Mantel r = 0.187; P = 0.18, respectively). We concluded that biomass produced and availability throughout the year, in addition to nutritional
and energy yield, are important criteria for selecting fodder trees for goat production. 相似文献
8.
Reinhardt V 《Journal of applied animal welfare science : JAAWS》2003,6(1):53-56
Macaques are biologically adapted to an arboreal or semiarboreal lifestyle. They spend much or most of the day and all of the night in elevated locations well off the ground as a safeguard against predators including humans. When they are on the ground during an alarming situation, they inevitably flee upward on trees, roofs, and other elevated, safe places (Chopra, Seth, & Seth, 1992; Lindburg, 1971; Roonwal & Mohnot, 1977). Free access to an elevated refuge is an essential security factor for them and, hence, a precondition for their emotional well-being. When they are kept in laboratories without proper access to the vertical dimension of their enclosure, macaques “might perceive the presence of humans above them as particularly threatening ”(National Research Council, 1998, p. 118). Given the choice, captive macaques will prefer high over low resting surfaces (O'Neill-Wagner, 1994), and dominant animals will be privileged to occupy high ones whereas subordinate individuals have to be content with low ones (Reinhardt, 1992). 相似文献
9.
Caroline Tauxe 《Dialectical Anthropology》1992,17(3):291-317
Conclusion The economic domination of household agricultural production by agribusiness on a national scale has been so complete that for many years analysts have concluded that the independent family farm has more existence in myth than in reality. Given that most farmers are excluded from realizing the ideal of family owned operations sustaining generation after generation, and even the fortunate few are subject to structural economic domination by big capital, one may ask why it is that rural families have persisted in valuing this way of life. In the face of these contradictions between the family farm myth and the experience of family farmers, the persistence of agricultural individualism and its Jeffersonian ideals of rural free-enterprise is remarkable.What to make, then, of these values, of this tradition? Has the independent family farm in Mercer County (and in the rest of North America) become a mere fiction and its values merely ideology? Traditional rural society is in danger of passing from anachronism to illusion with the increasing contradictions between its values and the realities arising out of its relationship to industrial capital. These values have become more rhetorical and imaginary; they lose their substance when compromised by families and communities responding to economic crisis by binding themselves ever more tightly to the very market forces that undermine them, and they lose their traditional meaning when used in advertising to promote further industrialization.The transformation of the American heartland myth comes full circle when it is appropriated by mass media in sympathetic reports on the farm crisis. Such coverage typically highlights an individual farm couple's stoic grief as the old family place is put up on the auction block, with lamentation over the loss of this traditional institution and breaking of a farm family's continuity. Focus on these emotionally wrenching and symbolically loaded images romanticizes and obscures the historical realities of farm family life, by suggesting that family farmers as a class have ever been otherwise than economically threatened and broken-up. Media analysis mourns the passing of family farms without criticizing the structures which grind them to pieces, and so is simply another reflection of the nostalgic and individualistic ideology that supports the very fragmentation it laments.After more than a century of struggle for survival, family farmers continue to be, in the words of one exasperated activist, victims of their own suicidal assumption that individual effort, a free market and elimination of governmental intervention will solve their economic problems. Farmers in the United States are political conservatives, and are notoriously difficult to organize in cooperative associations. As petty capitalists, they have been subject to the laws of motion of capitalist society, that have made their's a competitive way of life that is destructive of their families. Nonetheless, the dialectic between the ideals and the practical experiences of farming has produced ideological acquiescence to the system that has caused them so much suffering.
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10.
One of the five most important global biodiversity hotspots, the Neotropical Atlantic forest supports a diverse community of birds that nest in tree cavities. Cavity‐nesting birds may be particularly sensitive to forestry and agricultural practices that remove potential nest trees; however, there have been few efforts to determine what constitutes a potential nest tree in Neotropical forests. We aimed to determine the characteristics of trees and cavities used in nesting by excavators (species that excavate their own nest cavity) and secondary cavity‐nesters (species that rely on existing cavities), and to identify the characteristics of trees most likely to contain suitable cavities in the Atlantic forest of Argentina. We used univariate analyses and conditional logistic regression models to compare characteristics of nest trees paired with unused trees found over three breeding seasons (2006–2008). Excavators selected dead or unhealthy trees. Secondary cavity‐nesters primarily selected cavities that were deep and high on the tree, using live and dead cavity‐bearing trees in proportion to their availability. Nonexcavated cavities suitable for birds occurred primarily in live trees. They were most likely to develop in large‐diameter trees, especially grapia Apuleia leiocarpa and trees in co‐dominant or suppressed crown classes. To conserve cavity‐nesting birds of the Atlantic forest, we recommend a combination of policies, economic assistance, environmental education, and technical support for forest managers and small‐scale farmers, to maintain large healthy and unhealthy trees in commercial logging operations and on farms. 相似文献
11.
Interest in shade-grown coffee is now increasing because of declining coffee prices in the world market and an increasing trend toward green consumerism. It is therefore important to understand farmers' perception of the role of shade trees in coffee fields, an area that has not received deserving attention in research agendas. On the basis of detailed interviews involving both open-ended and closed questions with 83 small-scale coffee farmers in the Peninsula of Nicoya, Costa Rica, we found that characteristics that farmers considered important were mostly comparable to those stated in the literature. But some differences were also noted; examples included tree height (considered important by farmers, but not in literature) and leaf size (mentioned in literature, but not by farmers). Some tree species that were not considered beneficial as coffee shade trees were still retained in the fields because of the additional benefits they provided. Eighty-eight percent of farmers were interested in incorporating more trees, especially fruit trees, into their coffee plantations. The results of the study underscore the need for research on the little-studied area of interaction between coffee plants and fruit trees. 相似文献
12.
《Animal : an international journal of animal bioscience》2020,14(6):1293-1303
The growing interest in rotational crossbreeding in Western countries is due to its potential to improve reproductive and health performances of cows. Although a large amount of research focuses on assessing crossbred cows’ performances, how to manage the transition from purebred to rotational crossbred herds is under-explored. Based on a retrospective analysis of French dairy herd case studies, we aimed to identify and characterise technical pathways to make such a transition. In 2018, we performed semi-directive interviews on 26 commercial dairy farms. Data were collected to describe changes in breeding, replacement and culling management practices from the first crossbred mating with purebred cows to the management of a mainly crossbred herd in 2018. Based on a multivariate analysis, we identified two main guidelines structuring technical pathways to move towards rotational crossbred herds: (i) the depth and scale of change (i.e. farm v. herd) associated with the introduction of rotational crossbreeding in the whole-farm dynamics and (ii) the changes in herd replacement and breeding practices to adapt to the evolution of herd demographics induced by the evolution of the dairy crossbred mating rate over time (high from the beginning v. distributed over time). Hierarchical clustering discriminated three groups of farmers differing in their technical pathway to move towards a rotational crossbred herd. In pathway 1, farmers customised one or several rotational crossbreeding schemes to support whole-farm transition towards an organic or grass-based system. Once the scheme stabilised, they quickly implemented it and had to readjust replacement and culling practices to regulate imbalance in herd demographics induced by the improvement in cow fertility. In pathway 2, farmers also customised one or several rotational crossbreeding schemes to support whole-farm redesign but they implemented it more gradually in the herd, which induced no major imbalance in herd demographics. In pathway 3, farmers predefined a relatively well-known rotational crossbreeding scheme to correct fertility issues of purebred cows without any changes at the farm level. They implemented it quickly from the beginning and had to adapt herd replacement and culling to regulate imbalance in herd demographics induced by the improvement in cow fertility. These first empirical evidences on how dairy farmers manage the transition from a purebred to rotational crossbred herd provide original scientific and operational contributions. 相似文献
13.
Ian K. Dawson Ard Lengkeek John C. Weber Ramni Jamnadass 《Biodiversity and Conservation》2009,18(4):969-986
Tree species in agroforestry ecosystems contribute to the livelihoods of rural communities and play an important role in the conservation of biodiversity. Unless agroforestry landscapes are productive, however, farmers will not maintain or enhance the range and quality of tree species in them, and both income opportunities and biodiversity will be lost. Productivity depends on both tree species diversity and genetic (intra-specific) variation, but research on the latter has until recently not received the recognition it deserves. Worse, when knowledge on tree genetic variation in agroforestry systems has become available, it has not generally been linked in any systematic way with management, indicating a disjunction between research and field-level practice. In this essay, we attempt to bridge this gap by considering three questions: why is genetic diversity important in tree species? What is our current state of knowledge about intra-specific variation in trees in agroforestry systems? And, finally, what practical interventions are possible to support the conservation of this diversity in agricultural landscapes, while enhancing farmers’ livelihoods? A wide genetic base in agroforestry trees is essential to prevent inbreeding depression and allow adaptation to changing environmental conditions and to altering markets for tree products. Recent evidence shows, however, that many species are subject to poor germplasm collection practice, occur at low densities in farmland, and are found in highly aggregated distributions, all of which observations raise concerns about productivity and sustainability. A range of germplasm-access based interventions is necessary to improve current management, including the enhancement of community seed- and seedling-exchange networks, and the development of locally based tree domestication activities. Equally necessary, but more difficult to address, is the development of markets that support genetic diversity in tropical tree species; we discuss approaches by which this may be undertaken. 相似文献
14.
Sarunya Punkhun 《人类与生态风险评估》2020,26(2):283-294
AbstractTobacco is one of the crops using a lot of pesticides, especially organophosphate and carbamate pesticides. A cross-sectional study was conducted to investigate knowledge, attitudes, and Practices (KAP) related to blood cholinesterase levels related to pesticide use among tobacco farmers. A questionnaire and a reactive-paper finger blood test were completed by 44 tobacco farmers. The results showed that most of the participants were females (75.0%) between 51 and 60 years old (54.5%). Almost 95.5% of respondents acknowledged that they should wear a mask while spraying and most of them read pesticide labels before use (93.2%). Most of the tobacco farmers had moderate level of knowledge and attitudes, 63.6% and 70.5%, respectively and good practice (84.1%). The prevalence of risky levels of blood cholinesterase among tobacco farmers in the study area was high. The study found a strongly significant association between level of knowledge and blood cholinesterase level (P < 0.001). Policy implementation and risk communication will be introduced to the community in order to develop a safety program. Government authorities should be provided with the appropriate recommendations regarding pesticide exposure of tobacco farmers in this area. 相似文献
15.
Hydraulic lift in<Emphasis Type="Italic"> Acacia tortilis</Emphasis> trees on an East African savanna 总被引:6,自引:0,他引:6
Recent studies suggest that savanna trees in semi-arid areas can increase understorey plant production. We hypothesized that one of the mechanisms that explains the facilitation between trees and grasses in East African savannas is hydraulic lift (HL). HL in large Acacia tortilis trees was studied during the first 3 months of the dry season during a relatively wet year (1998) and a very dry year (2000). In 1998, we found distinct diel fluctuation in soil water potential (psi(s)), with increasing values during the night and decreasing again the following day. These fluctuations in psi(s )are consistent with other observations of HL and in A. tortilis were found up to 10 m from the tree. In 2000, during a severe drought, psi(s) measurements indicated that HL was largely absent. The finding that HL occurred in wetter years and not in drier years was supported by data obtained on the delta(18)O values in soil, rain and groundwater. The delta(18)O of water extracted from the xylem water of grasses indicated that when they grew near trees they had values similar to those of groundwater. This could be because they either (1) use water from deeper soil layers or (2) use hydraulically lifted water provided by the tree; this was not seen in the same grass species growing outside tree canopies. While our data indicate that HL indeed occurs under Acacia trees, it is also true that psi(s) was consistently lower under trees when compared to outside tree canopies. We believe that this is because tree-grass mixtures take up more water from the upper soil layers than is exuded by the tree each night. This limits the beneficial effect of HL for understorey grasses and suggests that in savannas both facilitation via HL and competition are active processes. The importance of each process may depend upon how wet or dry that particular site or year is. 相似文献
16.
Regina H. R. Sambuichi Daniela B. Vidal Flora B. Piasentin Jomar G. Jardim Thiago G. Viana Agna A. Menezes Durval L. N. Mello Dario Ahnert Virupax C. Baligar 《Biodiversity and Conservation》2012,21(4):1055-1077
In southern Bahia, Brazil, cabrucas are the traditional agroforests in which cacao trees are planted under thinned-out native forests. To analyze the role of
cabrucas in tree species conservation, we inventoried the non-cocoa trees in 1.0 ha plots of cabruca in 16 cocoa farms and compared our results with a similar survey undertaken in the early 1960s in the same region to analyze
the long term changes. We also interviewed 160 cocoa farmers to investigate their preferences for species and the main practices
used in managing shade trees. The cabrucas showed high levels of tree diversity for an agroforestry system (Shannon index ranging from 2.21 to 3.52) and also high variation
in structure and composition among the different farms. Forest specialist trees accounted for most species (63.9%) in the
survey and were among the species most preferred by the farmers, although we found evidence that some of these trees are gradually
being replaced by other species. Our results indicate that cabrucas are poor substitutes for undisturbed forests in terms of tree species richness, but their presence in human-altered landscapes
is of utmost importance to the conservation of forest tree species as they increase overall heterogeneity and may serve as
ecological corridors, additional habitats, and buffer zones. 相似文献
17.
This study aimed to identify and better understand management strategies that help livestock farmers adapt to changes in their production contexts, a fundamental challenge. A total of nine beef-cattle farmers were interviewed three times over 1 year to discuss 13 dimensions of livestock farming (e.g. reproduction, feeding, sales, etc.). Characterisation of management strategies rested on three main factors: (i) ranking of the dimensions according to the degree to which farmers desired to control them, (ii) reasons for the ranking and (iii) management guidelines. Although farmers agreed upon the rank of certain dimensions, such as herd management, they differed on that of others, such as sales and administration/regulations. Four motivation categories were identified: risk, pleasure, efficiency and ability to control the dimension. Three management guidelines were identified, which indicated that farmers managed for future survival of their farms at different scales (animal/herd v. whole-farm), involving different resources (biological v. financial) and based on different animal categories (reproductive cows v. animals sold). These results improve understanding of individual livestock farmers and their current management strategies by integrating the motivations behind their strategies. For this reason, they constitute methodological elements that agricultural advisors can use to provide relevant information to farmers while accommodating differences in farm management. 相似文献
18.
When adult male chimpanzees arrive at fruiting trees they commonly give long-distance pant-hoot vocalizations (arrival pant-hoots;
APHs). Previous hypotheses suggested that APHs benefit listeners by informing them about large food patches and that they
benefit callers by attracting allies or mates or both. We examined these ideas using data from 272 party arrivals at food
sources over a 16-month period in the Kibale Forest, Uganda. To standardize for social context, we focused on arrivals at
unoccupied trees. APHs at unoccupied trees were given only by parties containing at least one high-ranking adult male. In
contrast to previous studies, the probability of calling was not correlated with the amount of ripe fruit in the tree, and
APHs did not influence the probability of other parties arriving. Lower-ranking individuals that arrived at unoccupied trees
without calling were not punished, i.e., they were not charged more often than expected. We suggest that, instead of providing
information about the quality or quantity of food, APHs mark status. 相似文献
19.
Adrian D. Manning Philip Gibbons David B. Lindenmayer 《Journal of Applied Ecology》2009,46(4):915-919
1. Facilitating adaptive responses of organisms in modified landscape will be essential to overcome the negative effects of climate change and its interaction with land use change. Without such action, many organisms will be prevented from achieving the predicted range shifts they need to survive.
2. Scattered trees are a prominent feature of many modified landscapes, and could play an important role in facilitating climate change adaptation. They are keystone structures because of the disproportionally large ecological values and ecosystem services that they provide relative to the area they occupy in these landscapes. The provision of habitat and connectivity will be particularly relevant.
3. Scattered trees are declining in modified landscapes due to elevated tree mortality and poor recruitment often associated with intensive land use. The continuing global decline of scattered trees will undermine the capacity of many organisms to adapt to climate change.
4. Synthesis and applications. The sustainable management of scattered trees in modified landscapes could complement other strategies for facilitating climate change adaptation. They create continuous, though sparse, vegetation cover that permits multi-directional movements of biota across landscapes and ecological networks. They have the capacity to span ecosystems and climatic gradients that cannot be captured in formal reserves alone. The management of scattered trees should be an integral part of conservation objectives and agricultural activities in modified landscapes. Public investment, through mechanisms such as agri-environmental schemes, in rotational grazing, temporary set-asides, tree-planting and regulations that reduce clearing and early mortality among standing trees will improve the capacity of biota to adapt to climate change. 相似文献
2. Scattered trees are a prominent feature of many modified landscapes, and could play an important role in facilitating climate change adaptation. They are keystone structures because of the disproportionally large ecological values and ecosystem services that they provide relative to the area they occupy in these landscapes. The provision of habitat and connectivity will be particularly relevant.
3. Scattered trees are declining in modified landscapes due to elevated tree mortality and poor recruitment often associated with intensive land use. The continuing global decline of scattered trees will undermine the capacity of many organisms to adapt to climate change.
4. Synthesis and applications. The sustainable management of scattered trees in modified landscapes could complement other strategies for facilitating climate change adaptation. They create continuous, though sparse, vegetation cover that permits multi-directional movements of biota across landscapes and ecological networks. They have the capacity to span ecosystems and climatic gradients that cannot be captured in formal reserves alone. The management of scattered trees should be an integral part of conservation objectives and agricultural activities in modified landscapes. Public investment, through mechanisms such as agri-environmental schemes, in rotational grazing, temporary set-asides, tree-planting and regulations that reduce clearing and early mortality among standing trees will improve the capacity of biota to adapt to climate change. 相似文献
20.
Large quantities of dead wood can be generated by disturbances such as wildfires. Dead trees created by disturbances play many critical ecological roles in forest ecosystems globally. The ability of deadwood to serve its ecological roles is contingent, in part, on the length of time trees remain standing following disturbance. Here, we briefly outline the results of a 10-year study that aimed to quantify the rate of collapse of trees killed in a major wildfire in the wet ash forests of mainland south-eastern Australia. We also quantified the factors associated with dead tree collapse. Our analyses revealed that 23% of 417 measured trees collapsed between 2011 and 2021. The most parsimonious model of the factors influencing tree collapse revealed a strong effect of diameter; smaller diameter trees were more likely to collapse over the 10 years of our study than larger diameter trees. In addition, trees in small and large patches were more likely to collapse than trees in contiguous forest (where there had been no logging in the surrounding area). If current rates of tree fall are maintained, then many of trees initially measured will have collapsed by 2030. Such losses of dead trees will have major negative effects on key values of ash-type forests such as biodiversity conservation. 相似文献