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221.
Understanding movement in heterogeneous environments is central to predicting how landscape changes affect animal populations. Several recent studies point out an intriguing and distinctive looping behavior by butterflies at habitat patch edges and hypothesize that this behavior requires a new framework for analyzing animal movement. We show that this looping behavior could be caused by a longstanding movement model, biased correlated random walk, with bias toward habitat patches. The ability of this longstanding model to explain recent observations reinforces the point that butterflies respond to habitat heterogeneity and do not move randomly through heterogeneous environments. We discuss the implications of different movement models for predicting butterfly responses to landscape change, and our rationale for retaining longstanding movement models, rather than developing new modeling frameworks for looping behavior at patch edges. 相似文献
222.
Elizabeth A. Langridge Ana B. Sendova-Franks Nigel R. Franks 《Behavioral ecology and sociobiology》2008,62(12):1851-1861
Colonies of the ant Temnothorax albipennis improve their collective performance over successive emigrations (Langridge et al. Behav Ecol Sociobiol 56:523–529, 2004,
Behav Ecol Sociobiol 62:447–456, 2008). Here, by analysing the performance of individual transporters (workers that carry
the brood, queen and a proportion of adults), we investigate whether they spend less time at the old and new nests during
repeated emigrations. Transporters expedited choosing and picking up brood items at the old nest and depositing them in the
new nest. Such improvements were not associated with adult transport. Generally, when carrying brood items, but not when carrying
adults, transporters visited several locations in the new nest before depositing them. Transporters did not interact with
other adults when depositing brood items. Consequently, reductions in depositing times are the sum of time savings made by
individual transporters. By contrast, transporters spent most time interacting with other adults before picking up brood items
at the old nest. As the frequency of these interactions did not decline, we suggest the behaviours of interacting adults were
modified in a way that hastened their completion. Thus, reductions in picking-up times probably occur because of time saved
during interactions. 相似文献
223.
Diversity and host range of foliar fungal endophytes: are tropical leaves biodiversity hotspots? 总被引:2,自引:0,他引:2
Fungal endophytes are found in asymptomatic photosynthetic tissues of all major lineages of land plants. The ubiquity of these cryptic symbionts is clear, but the scale of their diversity, host range, and geographic distributions are unknown. To explore the putative hyperdiversity of tropical leaf endophytes, we compared endophyte communities along a broad latitudinal gradient from the Canadian arctic to the lowland tropical forest of central Panama. Here, we use molecular sequence data from 1403 endophyte strains to show that endophytes increase in incidence, diversity, and host breadth from arctic to tropical sites. Endophyte communities from higher latitudes are characterized by relatively few species from many different classes of Ascomycota, whereas tropical endophyte assemblages are dominated by a small number of classes with a very large number of endophytic species. The most easily cultivated endophytes from tropical plants have wide host ranges, but communities are dominated by a large number of rare species whose host range is unclear. Even when only the most easily cultured species are considered, leaves of tropical trees represent hotspots of fungal species diversity, containing numerous species not yet recovered from other biomes. The challenge remains to recover and identify those elusive and rarely cultured taxa with narrower host ranges, and to elucidate the ecological roles of these little-known symbionts in tropical forests. 相似文献
224.
Predators, parasitoids, and pathogens: a cross-cutting examination of intraguild predation theory 总被引:2,自引:0,他引:2
Although the canonical concept of intraguild predation evokes images of predators and prey, several subdisciplines within ecology have developed theory not specifically framed in terms of predation and competition and often using system-specific terminology, yet functionally quite similar. Here, we formulate models combining exploitation and competition in predator-prey, host-parasitoid, and host-pathogen communities to compare dynamics, food web structure, and coexistence criteria for these disparate communities. Although dynamic stability in the coexistence region varies strongly among systems, in all cases coexistence of two consumers on a single resource occurs only if the intraguild prey species is more efficient than the intraguild predator at suppressing the abundance of the basal resource, and if the intraguild predator accrues a sufficient gain from attacking the intraguild prey. In addition, equilibrial abundances of all species in all three formulations respond similarly to increases in productivity of the basal resource. Our understanding of predator-prey and parasitoid-host communities has benefited from explicit examination of intraguild predation (IGP) theory, and we suggest that future research examining pathogen communities, in particular, will benefit substantially from explicit recognition of predictions from IGP theory. 相似文献
225.
226.
Weslynne Ashton Suzana Russell Elizabeth Futch 《Journal of Environmental Planning and Management》2017,60(12):2133-2149
Manufacturers around the world green their businesses for a variety of reasons, including competitiveness, social responsibility, and external stakeholder pressure. However, small and medium enterprises (SMEs) are thought to lag behind larger ones in the adoption of green business practices. This paper explores the motivations for US Midwestern SMEs adopting a variety of green business practices, using a survey of 59 SMEs in the tool and die manufacturing industry. The majority of firms appear to be internally motivated to implement green practices – driven primarily by cost and competitiveness concerns, more than by social responsibility concerns. External coercive pressure from government or customers does not appear to be a significant motivation for these SMEs. However, informal pressure through government incentives and support programs, as well as mimetic pressure through peer learning via industry associations, appear to be more effective in helping these SMEs to further ‘go green.’ 相似文献
227.
Irene Iniesta-Arandia Federica Ravera Stephanie Buechler Isabel Díaz-Reviriego María E. Fernández-Giménez Maureen G. Reed Mary Thompson-Hall Hailey Wilmer Lemlem Aregu Philippa Cohen Houria Djoudi Sarah Lawless Berta Martín-López Thomas Smucker Grace B. Villamor Elizabeth Edna Wangui 《Ambio》2016,45(3):383-393
This synthesis article joins the authors of the special issue “Gender perspectives in resilience, vulnerability and adaptation to global environmental change” in a common reflective dialogue about the main contributions of their papers. In sum, here we reflect on links between gender and feminist approaches to research in adaptation and resilience in global environmental change (GEC). The main theoretical contributions of this special issue are threefold: emphasizing the relevance of power relations in feminist political ecology, bringing the livelihood and intersectionality approaches into GEC, and linking resilience theories and critical feminist research. Empirical insights on key debates in GEC studies are also highlighted from the nine cases analysed, from Europe, the Americas, Asia, Africa and the Pacific. Further, the special issue also contributes to broaden the gender approach in adaptation to GEC by incorporating research sites in the Global North alongside sites from the Global South. This paper examines and compares the main approaches adopted (e.g. qualitative or mixed methods) and the methodological challenges that derive from intersectional perspectives. Finally, key messages for policy agendas and further research are drawn from the common reflection. 相似文献
228.
Abigail Bennett Xavier Basurto John Virdin Xinyan Lin Samantha J. Betances Martin D. Smith Edward H. Allison Barbara A. Best Kelly D. Brownell Lisa M. Campbell Christopher D. Golden Elizabeth Havice Christina C. Hicks Peter J. Jacques Kristin Kleisner Niels Lindquist Rafaella Lobo Grant D. Murray Michelle Nowlin Pawan G. Patil Douglas N. Rader Stephen E. Roady Shakuntala H. Thilsted Sarah Zoubek 《Ambio》2021,50(5):981
The international development community is off-track from meeting targets for alleviating global malnutrition. Meanwhile, there is growing consensus across scientific disciplines that fish plays a crucial role in food and nutrition security. However, this ‘fish as food’ perspective has yet to translate into policy and development funding priorities. We argue that the traditional framing of fish as a natural resource emphasizes economic development and biodiversity conservation objectives, whereas situating fish within a food systems perspective can lead to innovative policies and investments that promote nutrition-sensitive and socially equitable capture fisheries and aquaculture. This paper highlights four pillars of research needs and policy directions toward this end. Ultimately, recognizing and working to enhance the role of fish in alleviating hunger and malnutrition can provide an additional long-term development incentive, beyond revenue generation and biodiversity conservation, for governments, international development organizations, and society more broadly to invest in the sustainability of capture fisheries and aquaculture.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01451-4) contains supplementary material, which is available to authorized users. 相似文献
229.
230.
Richard T. Woodward Amanda Stronza Elizabeth Shapiro‐Garza Lee A. Fitzgerald 《Natural resources forum》2014,38(4):235-247
This paper provides a broad evaluation of the implications of market‐based conservation (MBC) strategies from economic, social and ecological perspectives. After reviewing the economic theory that underlies MBC initiatives, we develop a list of approaches that have been labeled as “market‐based”, and categorize them according to the degree to which they are free‐standing markets or require the intervention of the state. A multidisciplinary critique reveals the potential problems and pitfalls of MBC are due to a lack of ability to deal with dynamic systems in the real world. The dynamics of these three systems can undermine the intended goals of MBC. 相似文献