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1.
Leaf‐Litter Mixtures Affect Breakdown and Macroinvertebrate Colonization Rates in a Stream Ecosystem
Manuela Abelho 《International Review of Hydrobiology》2009,94(4):436-451
Previous work in terrestrial and aquatic ecosystems has suggested that the relationship between breakdown rates of leaf litter and plant species richness may change unpredictability due to non‐additive effects mediated by the presence of key‐species. By using single‐ and mixed‐species leaf bags (7 possible combinations of three litter species differing in toughness; common alder [Alnus glutinosa ], sweet chestnut [Castanea sativa ], and Spanish oak [Quercus ilex ilex ]), I tested whether leaf species diversity, measured as richness and composition, affects breakdown dynamics and macroinvertebrate colonization (abundance, richness and composition) during 90 days incubation in a stream. Decomposition rates were additive, i.e., observed decomposition rates were not different from expected ones. However, decomposition rates of individual leaf species were affected by the mixture, i.e., there were species‐specific responses to mixing litter. The invertebrate communities colonizing the mixtures were not richer and more diverse in mixtures than in single‐species leaf bags. On the opposite, mixing leaf species had a negative, non‐additive effect on rates of shredder and taxa colonization and on macroinvertebrate diversity. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
2.
Long-term presence of tree species but not chemical diversity affect litter mixture effects on decomposition in a neotropical rainforest 总被引:1,自引:0,他引:1
Plant litter diversity effects on decomposition rates are frequently reported, but with a strong bias towards temperate ecosystems.
Altered decomposition and nutrient recycling with changing litter diversity may be particularly important in tree species-rich
tropical rainforests on nutrient-poor soils. Using 28 different mixtures of leaf litter from 16 Amazonian rainforest tree
species, we tested the hypothesis that litter mixture effects on decomposition increase with increasing functional litter
diversity. Litter mixtures and all single litter species were exposed in the field for 9 months using custom-made microcosms
with soil fauna access. In order to test the hypothesis that the long-term presence of tree species contributing to the litter
mixtures increases mixture effects on decomposition, microcosms were installed in a plantation at sites including the respective
tree species composition and in a nearby natural forest where these tree species are absent. We found that mixture decomposition
deviated from predictions based on single species, with predominantly synergistic effects. Functional litter diversity, defined
as either richness, evenness, or divergence based on a wide range of chemical traits, did not explain the observed litter
mixture effects. However, synergistic effects in litter mixtures increased with the long-term presence of tree species contributing
to these mixtures as the home field advantage hypothesis assumes. Our data suggest that complementarity effects on mixed litter
decomposition may emerge through long-term interactions between aboveground and belowground biota. 相似文献
3.
Effects of microclimate,litter type,and mesh size on leaf litter decomposition along an elevation gradient in the Wuyi Mountains,China 总被引:1,自引:0,他引:1
Litter decomposition is an important ecosystem process regulated by both biotic factors (e.g., decomposers and litter types)
and abiotic factors (e.g., temperature and moisture). This study examined the regulatory effects of soil fauna and microclimate
on decomposition of two substrates (Castanopsis carlesii and Pinus taiwanensis) along an elevation gradient in four ecosystems of zonal vegetation types in southeastern China: evergreen broadleaf forest
(EVB), coniferous forest (COF), dwarf forest (DWF), and alpine meadow (ALM). Our objective was to identify the mechanisms
by which microclimate, substrate, and fauna control litter decomposition, especially where variations in ecosystem structure
and environment are markedly shown across an elevation gradient. The hypotheses were as follows: (1) litter decomposition
within the same litter type would decrease across the elevation gradient, (2) litter decomposition would be lower in poorer
nutrient quality substrate across the four sites, and (3) litter dynamics, influenced by strong interactions among ecosystem
type, litter type, and decomposers, would vary by elevation gradient due to microclimate effects (i.e., temperature and moisture).
The decomposition rates of C. carlesii were significantly higher than those of P. taiwanensis at EVB, COF, and DWF sites; however, they were not significantly different at the ALM site. Low elevation forests possessed
a microclimate (warm and humid) that favors decomposer activities and also appeared to possess a decomposer community adapted
to consuming large amounts of leaf litter, as indicated by the rapid leaf litter loss. Litter decomposition in micro-mesh
bags proceeded more slowly compared to litter in meso-mesh and macro-mesh litterbags across the elevation gradient, indicating
that restricting some detritivore access to litter reduced litter mass loss. We suggest that microclimate and faunal contributions
to plant litter decomposition differ markedly across the ecosystems in the Wuyi Mountains. 相似文献
4.
Abstract Allochtonous leaf litter is an important source of energy and nutrients for invertebrates in cave ecosystems. A change to the quality or quantity of litter entering caves has the potential to disrupt the structure and function of cave communities. In this study, we adopted an experimental approach to examine rates of leaf litter decomposition and the invertebrate assemblages colonizing native and exotic leaf litter in limestone caves in the Jenolan Caves Karst Conservation Reserve, New South Wales, Australia. We deployed traps containing leaf litter from exotic sycamore (Acer pseudoplatanus) and radiata pine (Pinus radiata) trees and native eucalypts (Eucalyptus spp.) in twilight zones (near the cave entrance) and areas deep within the caves for 3 months. Thirty‐two invertebrate morphospecies were recorded from the litter traps, with greater richness and abundance evident in the samples from the twilight zone compared with areas deep within the cave. Sycamore litter had significantly greater richness and abundance of invertebrates compared with eucalypt and pine litter in samples from the twilight zone, but there was no difference in richness or abundance among litter samples placed deep within the cave. Relative rates of decay of the three litters were sycamore > eucalypt > pine. We discuss the potential for the higher decomposition rates and specific leaf area in sycamores to explain their higher invertebrate diversity and abundance. Our findings have important implications for the management of exotic plants and the contribution of their leaf litter to subterranean ecosystems. 相似文献
5.
6.
Leaf litter decomposition in temperate deciduous forest stands with a decreasing fraction of beech (Fagus sylvatica) 总被引:2,自引:0,他引:2
We hypothesised that the decomposition rates of leaf litter will increase along a gradient of decreasing fraction of the European
beech (Fagus sylvatica) and increasing tree species diversity in the generally beech-dominated Central European temperate deciduous forests due
to an increase in litter quality. We studied the decomposition of leaf litter including its lignin fraction in monospecific
(pure beech) stands and in stands with up to five tree genera (Acer spp., Carpinus betulus, Fagus sylvatica, Fraxinus excelsior, Tilia spp.) using a litterbag approach. Litter and lignin decomposition was more rapid in stand-representative litter from multispecific
stands than in litter from pure beech stands. Except for beech litter, the decomposition rates of species-specific tree litter
did not differ significantly among the stand types, but were most rapid in Fraxinus excelsior and slowest in beech in an interspecific comparison. Pairwise comparisons of the decomposition of beech litter with litter
of the other tree species (except for Acer
platanoides) revealed a “home field advantage” of up to 20% (more rapid litter decomposition in stands with a high fraction of its own
species than in stands with a different tree species composition). Decomposition of stand-representative litter mixtures displayed
additive characteristics, not significantly more rapid than predicted by the decomposition of litter from the individual tree
species. Leaf litter decomposition rates were positively correlated with the initial N and Ca concentrations of the litter,
and negatively with the initial C:N, C:P and lignin:N ratios. The results support our hypothesis that the overall decomposition
rates are mainly influenced by the chemical composition of the individual litter species. Thus, the fraction of individual
tree species in the species composition seems to be more important for the litter decomposition rates than tree species diversity
itself. 相似文献
7.
Carlos Iñiguez‐Armijos Sirkka Rausche Augusta Cueva Aminael Sánchez‐Rodríguez Carlos Espinosa Lutz Breuer 《Ecology and evolution》2016,6(14):4849-4865
Tropical montane ecosystems of the Andes are critically threatened by a rapid land‐use change which can potentially affect stream variables, aquatic communities, and ecosystem processes such as leaf litter breakdown. However, these effects have not been sufficiently investigated in the Andean region and at high altitude locations in general. Here, we studied the influence of land use (forest–pasture–urban) on stream physico‐chemical variables (e.g., water temperature, nutrient concentration, and pH), aquatic communities (macroinvertebrates and aquatic fungi) and leaf litter breakdown rates in Andean streams (southern Ecuador), and how variation in those stream physico‐chemical variables affect macroinvertebrates and fungi related to leaf litter breakdown. We found that pH, water temperature, and nutrient concentration increased along the land‐use gradient. Macroinvertebrate communities were significantly different between land uses. Shredder richness and abundance were lower in pasture than forest sites and totally absent in urban sites, and fungal richness and biomass were higher in forest sites than in pasture and urban sites. Leaf litter breakdown rates became slower as riparian land use changed from natural to anthropogenically disturbed conditions and were largely determined by pH, water temperature, phosphate concentration, fungal activity, and single species of leaf‐shredding invertebrates. Our findings provide evidence that leaf litter breakdown in Andean streams is sensitive to riparian land‐use change, with urban streams being the most affected. In addition, this study highlights the role of fungal biomass and shredder species (Phylloicus; Trichoptera and Anchytarsus; Coleoptera) on leaf litter breakdown in Andean streams and the contribution of aquatic fungi in supporting this ecosystem process when shredders are absent or present low abundance in streams affected by urbanization. Finally, we summarize important implications in terms of managing of native vegetation and riparian buffers to promote ecological integrity and functioning of tropical Andean stream ecosystems. 相似文献
8.
Franca Sangiorgio Douglas S. Glazier Giorgio Mancinelli Alberto Basset 《Hydrobiologia》2010,654(1):227-236
Although habitat size is known to influence both structural and functional properties of ecosystems, there have been few attempts
to assess the influence of habitat size on ecosystem processes. Here we investigated the relationships between leaf litter
decomposition and ecosystem surface area, macroinvertebrates and physico-chemical factors in five freshwater springs located
in Huntingdon County (Pennsylvania, U.S.A.). Leaves of Ulmus americana L. were used to study leaf litter breakdown with the litter-bag technique. Field work was carried out at one sampling station
per spring, each with eight replicates per sampling time (3, 20, 40 days), from April to May 2004. American elm leaves decomposed
at different rates in the different springs, varying inversely with the spring area. The leaf bags were colonized by 16 taxa
of benthic macrofauna, amongst which scrapers and shredders were the most common guild. Macroinvertebrate species richness
co-varied with spring area, but not with other physico-chemical variables. Moreover, a significant inverse relationship was
observed between American elm leaf decay rate and taxonomic richness. In the studied springs, habitat area was an ecosystem
feature indirectly affecting detritus processing by influencing the structure of the detrital food web within the systems. 相似文献
9.
Leaf litter decomposition in a southern Sonoran Desert ecosystem, northwestern Mexico: Effects of habitat and litter quality 总被引:2,自引:0,他引:2
Leaf litter decomposition of dominant woody perennial species in the three most common habitats of the southern Sonoran Desert was studied using the litter-bag method. Our objective was to assess the influence of litter quality on decomposition rates in three contrasting desert environments. The hypotheses were: (1) decomposition rates within the same litter type are faster in more mesic habitats, (2) decomposition rates are lower in higher lignin content or lower nutrient quality substrates, and (3) species-rich substrates enhance decomposition rates. For all litter types and habitats, a rapid loss of mass occurred during the summer rains at the start of the experiment, but total loss within the same litter type differed significantly among habitats. Decay rates were not higher in the more mesic habitat, but in the dry plains where solar irradiance and termite activity were highest. While termite activity was less important in the arroyos and absent in the hillsides habitats, proliferation of fungal mycelium in these sites was much higher than in the plains, suggesting that biotic and abiotic factors act both independently of litter richness. Lignin content seems to be an important factor controlling the loss of litter, because decay rates were inversely related to litter initial lignin content in all three habitats. Leaf litter diversity did not enhance rates of decomposition. The leaf litter mixture had k-values similar to the most recalcitrant monospecific litter in all three habitats, indicating a neutral or even antagonistic role of species-specific compounds in decomposition rates. 相似文献
10.
11.
Human disturbances both decrease the number of species in ecosystems and change their relative abundances. Here we present field evidence demonstrating that shifts in species abundances can have effects on ecosystem functioning that are as great as those from shifts in species richness. We investigated spatial and temporal variability of leaf decomposition rates and community metrics of leaf‐eating invertebrates (shredders) in streams. The shredder community composition dramatically influenced the diversity–function relationship; decomposition was much higher for a given species richness at sites with high species dominance than at sites where dominance was low. Decomposition rates also markedly depended on the identity of the dominant species. Further, dominance effects on decomposition varied seasonally and the number of species required for maintaining decomposition increased with increasing evenness. These findings reveal important but less obvious aspects of the biodiversity–ecosystem functioning relationship. 相似文献
12.
Our research examined the effect of Azteca sericeasur, a keystone arboreal ant, on the decomposition of leaf litter of the shade tree, Inga micheliana, in coffee agro-ecosystems. This interaction is important in understanding spatial heterogeneity in decomposition. We hypothesized that A. sericeasur could affect leaf litter decomposition by excluding other ants, which could release decomposers, like collembolans, from predation pressure. Determining the relative strengths of these interactions can illuminate the importance of A. sericeasur in decomposition and nutrient cycling processes. We assessed the ant and arthropod communities surrounding 10 pairs of trees, where each pair included one shade tree with an established A. sericeasur nest. Tuna baits were used in conjunction with pitfall traps to assess the ant and arthropod community, and litterbags with I. micheliana leaf litter were used to assess rates of decomposition. The species richness of ants did not change in proximity to A. sericeasur nests, though the ant communities were distinct. Abundance of Collembola and community composition of other invertebrates did not change in the presence of A. sericeasur nests, and there were no differences in leaf litter decomposition rates. This contradicts past studies that suggest A. sericeasur reduces ant species richness in its territory. We suggest that other ants may avoid A. sericeasur by moving within and beneath the leaf litter. Our results indicate that there is no net effect of A. sericeasur on leaf litter decomposition. 相似文献
13.
We determined rates of decomposition and asymbiotic nitrogen fixation in the leaf litter of Cheirodendron spp. on the Hawaiian Islands. Leaf litter was collected from four sites on a long soil-age gradient (300 yr to 4.1 M yr) and decomposed at two sites that differed widely in substrate age and nutrient availability. Rates of decomposition were higher in litter decomposed at the older site, where nutrient availability was greater. A substantial amount of nitrogen and phosphorus immobilization occurred in litter decomposed at the older site, with more immobilization occurring in litter with lower initial nitrogen and phosphorus concentrations, suggesting both supply and demand controls on nutrient immobilization. Potential rates of nitrogen fixation were very low in the first 25 d (0–5 nmol acetylene/gdw/h), rose to much higher rates by 70 d (20–45 nmol), and then declined by 140 d. We found no significant difference in rates of potential nitrogen fixation between sites of decomposition, but there was a strong substrate effect, with higher rates in litter with low lignin, low nitrogen, and high phosphorus. Where significant immobilization of nitrogen occurred for decomposing Cheirodendron, nitrogen fixation could have comprised no more than 10 percent of immobilized nitrogen. Overall, rates of nitrogen fixation were dependent on the source of the decomposing substrate but not on the site of decomposition, while short-term decomposition and nutrient immobilization were strongly dependent on the site of decomposition but not as much on the source of the decomposing substrate. 相似文献
14.
Following studies that showed negative effects of species loss on ecosystem functioning, newer studies have started to investigate if similar consequences could result from reductions of genetic diversity within species. We tested the influence of genotypic richness and dissimilarity (plots containing one, three, six or 12 genotypes) in stands of the invasive plant Solidago canadensis in China on the decomposition of its leaf litter and associated soil animals over five monthly time intervals. We found that the logarithm of genotypic richness was positively linearly related to mass loss of C, N and P from the litter and to richness and abundance of soil animals on the litter samples. The mixing proportion of litter from two sites, but not genotypic dissimilarity of mixtures, had additional effects on measured variables. The litter diversity effects on soil animals were particularly strong under the most stressful conditions of hot weather in July: at this time richness and abundance of soil animals were higher in 12-genotype litter mixtures than even in the highest corresponding one-genotype litter. The litter diversity effects on decomposition were in part mediated by soil animals: the abundance of Acarina, when used as covariate in the analysis, fully explained the litter diversity effects on mass loss of N and P. Overall, our study shows that high genotypic richness of S. canadensis leaf litter positively affects richness and abundance of soil animals, which in turn accelerate litter decomposition and P release from litter. 相似文献
15.
Stephen P. Yanoviak 《Oecologia》1999,120(1):147-155
Detritus quality and quantity affect macroinvertebrate productivity and distribution in many freshwater ecosystems. This
study experimentally investigated the effects of leaf litter from Ceiba pentandra, Dipteryx panamensis, Ficus yoponensis, and Platypodium elegans on macroinvertebrate species composition, richness, and abundance in artificial water-filled tree holes in a lowland moist
forest of Panama. Species composition was similar among treatments, but species richness and longevity differed among litter
types and were consistently highest with Platypodium litter. Similar patterns were observed in natural tree holes of the focal tree species. The mosquito Culex mollis was the most abundant species in the field experiment. Average conductivity and dissolved oxygen concentration differed among
leaf species, but pH did not. Leaf toughness was positively correlated with mean macroinvertebrate abundance and cumulative
species richness. A laboratory experiment measured C. mollis yield and pupation time in tree hole microcosms containing the four litter species. Cumulative mosquito mass and time to
pupation differed among leaf litter species, with Platypodium litter supporting the greatest yield. Pupation was slowest on Ceiba litter. Grazing by mosquito larvae facilitated leaf decomposition in all treatments. Results suggest that differences in
macroinvertebrate species richness and mosquito yield can be attributed to differences in nutritional quality among litter
species.
Received: 14 October 1998 / Accepted: 21 February 1999 相似文献
16.
Aurea Luiza Lemes da Silva William Padilha Lemes Jssica Andriotti Mauricio Mello Petrucio Maria Joo Feio 《Austral ecology》2020,45(5):644-658
Land‐use changes such as conversion of natural forest to rural and urban areas have been considered as main drivers of ecosystem functions decline, and a large variety of indicators has been used to investigate these effects. Here, we used a replicated litter‐bag experiment to investigate the effects of land‐use changes on the leaf‐litter breakdown process and leaf‐associated invertebrates along the forest–pasture–urban gradient located in a subtropical island (Florianópolis, SC, Brazil). We identified the invertebrates and measured the litter breakdown rates using the litter bags approach. Litter bags containing 3 g of dry leaf of Alchornea triplinervia were deployed on forest rural and urban streams. Principal component analysis, based on physico‐chemical variables which, confirmed a gradient of degradation from forest to urban streams with intermediate values in rural areas. In accordance, shredder richness and abundance were lower in rural and urban than in forest streams. The land‐use changes led also to the dominance of tolerant generalist taxa (Chironomidae and Oligochaeta) reducing the taxonomic and functional diversity in these sites. Leaf‐litter breakdown rates decreased from forest to rural and finally to urban areas and were associated with changes in pH, water velocity, dissolved oxygen and abundance of leaf‐shredding invertebrates, although global decomposition rates did not differ between rural and urban streams. Overall, this study showed that land‐use changes, namely to rural and urban areas, have a strong impact on tropical streams ecosystems, in both processes and communities composition and structure. Despite of being apparently a smaller transformation of landscape, rural land use is comparable to urbanisation in terms of impact in stream functioning. It is thus critical to carefully plan urban development and maintain forest areas in the island of Florianópolis in order to preserve its natural biodiversity and aquatic ecosystems functioning. 相似文献
17.
Recent research has shown that genetic variation can directly impact community and ecosystem level processes. Populus tremuloides (trembling aspen) is an extremely widespread and genetically diverse tree species important to many North American forest
ecosystems. Using leaf litter from five genotypes grown in a common garden under two nutrient treatments, we tracked litter
decomposition in a natural aspen stand for 1 year. Here we show that aspen leaf litter decomposes and releases carbon, nitrogen,
and sulfur in relation to its genetic identity. In a secondary experiment, we show that the genetic diversity of aspen litter
mixtures can influence decomposition, however weakly so. Overall, nutrient treatments influenced leaf litter decomposition
the most, followed by genetic identity, and then by genetic diversity (if at all in some cases). In this widespread, genetically
diverse, and dominant species, genetic variation within a single species is important to ecosystem functioning. The relatively
weak effect of genetic diversity on the processes measured here does not preclude its importance to ecosystem functioning,
but does suggest that genetic identity and composition are more important than genetic diversity per se. 相似文献
18.
Earthworm invasion in North American temperate forest reduces forest floor mass, yet the interactions between litter composition, invasive earthworm community composition, and forest floor structure and composition are not well understood. For 2?years, we compared disappearance of leaf litter in field mesocosms in which we manipulated litter composition (monocultures of Quercus rubra, Acer saccharum, and Tilia americana litter, and an equal mixture of all three) and thereby the initial litter chemistry (C, C fractions, N, Ca) in sites with and without the major litter-feeding invasive earthworm species. The disappearance of litter mass followed the same ranking at both the sites: T. americana?>?equal mixtures?>?A. saccharum?≥?Q. rubra. However, differences in disappearance rate between the sites depended on litter composition and time. The differences in mass loss among litters of different compositions were greatest at the site invaded by the large litter-feeding earthworm, Lumbricus terrestris, and especially for T. americana and the mixture. Similarly, observed disappearance of the litter mixture was faster than predicted by an additive model at the site with L. terrestris, especially for the higher quality litter component in early summer. Initial litter calcium content was the best predictor (R 2?≥?0.90) of overall litter mass remaining each year, supporting the idea of the importance of calcium in forest floor dynamics, especially in the presence of calciferous, invasive earthworms. 相似文献
19.
Tree species richness affects litter production and decomposition rates in a tropical biodiversity experiment 总被引:5,自引:0,他引:5
We report data on leaf litter production and decomposition from a manipulative biodiversity experiment with trees in tropical Panama, which has been designed to explore the relationship between tree diversity and ecosystem functioning. A total of 24 plots (2025 m2) were established in 2001 using six native tree species, with 1‐, 3‐, and 6‐species mixtures. We estimated litter production during the dry season 2005 with litter traps; decomposition was assessed with a litter bag approach during the following wet season. Litter production during the course of the dry season was highly variable among the tree species. Tree diversity significantly affected litter production, and the majority of the intermediate diverse mixtures had higher litter yields than expected based on yields in monoculture. In contrast, high diverse mixtures did not show such overyielding in litter production. Litter decomposition rates were also highly species‐specific, and were related to various measures of litter quality (C/N, lignin/N, fibre content). We found no overall effect of litter diversity if the entire litter mixtures were analyzed, i.e. mixing species resulted in pure additive effects and observed decomposition rates were not different from expected rates. However, the individual species changed their decomposition pattern depending on the diversity of the litter mixture, i.e. there were species‐specific responses to mixing litter. The analysis of temporal C and N dynamics within litter mixtures gave only limited evidence for nutrient transfer among litters of different quality. At this early stage of our tree diversity experiment, there are no coherent and general effects of tree species richness on both litter production and decomposition. Within the scope of the biodiversity‐ecosystem functioning relationship, our results therefore highlight the process‐specific effects diversity may have. Additionally, species‐specific effects on ecosystem processes and their temporal dynamics are important, but such effects may change along the gradient of tree diversity. 相似文献
20.
We investigated the linkages between leaf litter quality and decomposability in a savanna plant community dominated by palatable-spinescent
tree species. We measured: (1) leaf litter decomposability across five woody species that differ in leaf chemistry; (2) mass
decomposition, nitrogen (N); and carbon (C) dynamics in leaf litter of a staple browse species (Acacia nigrescens) as well as (3) variation in litter composition across six sites that experienced very different histories of attack from
large herbivores. All decomposition trials included litter bags filled with chopped straw to control for variation in site
effects. We found a positive relationship between litter quality and decomposability, but we also found that Acacia and straw litter mass remaining did not significantly vary between heavily and lightly browsed sites. This is despite the
fact that both the quality and composition of litter returned to the soil were significantly different across sites. We observed
greater N resorption from senescing Acacia leaves at heavily browsed sites, which in turn contributed to increase the C:N ratio of leaf litter and caused greater litter
N immobilization over time. This, together with the significantly lower tree- and herb-leaf litter mass beneath heavily browsed
trees, should negatively affect decomposition rates. However, estimated dung and urine N deposition from both browsers and
grazers was significantly greater at high- than at low-herbivory sites. We hypothesize that N inputs from dung and urine boost
litter N mineralization and decomposition (especially following seasonal rainfall events), and thereby offset the effects
of poor leaf litter quality at chronically browsed sites.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献