مقاله انگلیسی رایگان در مورد آشکاری سازی تاثیرات استفاده از زمین، فصل و زیستگاه – اسپرینگر 2018

The transfer of aquatic resource subsidies into terrestrial food webs via the winged adult stages of aquatic insects is recognized as a key component in the functioning of riverine networks (Moldenke and Linden 2007; Lamberti et al. 2010; Muehlbauer et al. 2014). Not only do aquatic insects often emerge with very high abundance and biomass, but they also carry nutrients and essential lipids produced within aquatic environments (Baxter et al. 2005; Gratton et al. 2008; Gladyshev et al. 2009; Torres-Ruiz and Wehr 2010). These aquatic insect subsidies support a multitude of organisms in riparian communities, including arthropods (Collier et al. 2002; Burdon et al. 2013), birds (Gray 1993; Poulin et al. 2010) and bats (Fukui et al. 2006). Research is now increasingly focussing on understanding how anthropogenic disturbances alter the factors that regulate the production and dispersal of aquatic insect subsidies, and their uptake into terrestrial food webs (Tockner et al. 1999; Petersen et al. 2004; Jonsson et al. 2013; Kautza and Sullivan 2015; Carlson et al. 2016; Greenwood and Booker 2016). Key factors regulating the incorporation of aquatic subsidies into terrestrial food webs include the timing of adult aquatic insect emergence relative to the resource requirements of terrestrial consumers, the dispersal patterns of adult aquatic insects into the terrestrial environment, and rates of consumption of the aquatic subsidy by terrestrial consumers (Polis et al. 1997; Nakano and Murakami 2001; Marczak et al. 2007). Accordingly, much research attention has focused on how terrestrial environmental features regulate subsidy dispersal and the responses of terrestrial consumers (e.g. forest cover, complexity of ground habitats, availability of terrestrial resources), and on how human activities alter these linkages (Petersen et al. 2004; Greenwood and McIntosh 2008; Marczak and Richardson 2008; Stenroth et al. 2015). However, both the timing and extent of dispersal by adult aquatic insects are further regulated by their species-specific life history traits (Greenwood and Booker 2016). These traits are components of a species’ phenotype that regulate when and how often individuals emerge from the aquatic larval to terrestrial adult state (e.g. voltinism, seasonal syncronicity), and how far from the natal stream individuals might disperse (e.g. adult flying strength, flight distance, body size) (Petchey and Gaston 2006; Truchy et al. 2015; Greenwood and Booker 2016), and which thereby influence their availability as resource subsidies to terrestrial consumers in time and space (Table 1). Anthropogenic disturbances can have particularly strong effects on the species trait composition of freshwater macroinvertebrate communities (e.g. Frainer and McKie 2015). Significantly, species traits are not independent entities, but because of ecological and evolutionary trade-offs involved in life-history strategies (Verberk et al. 2008) are often linked into clusters or “syndromes”, i.e., a group of tightly linked traits strongly associated with particular genera or families (Reich et al. 2003; Poff et al. 2006). Indeed, communities dominated by smaller, short-lived organisms with more flexible life cycles and generalist feeding behaviours often dominate human impacted streams (Statzner and Béche 2010), as species with these characteristics are favoured under the more extreme and less certain environmental conditions of degraded habitats. Human impacts on the composition of linked dispersal and life history traits thus need to be incorporated into a broader framework for understanding variation in how aquatic insects subsidize terrestrial food webs.