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1.
Many plants release allelopathic chemicals that can inhibit germination, growth, and/or survival in neighboring plants. These impacts appear magnified with the invasion of some non-native plants which may produce allelochemicals against which native fauna have not co-evolved resistance. Our objective was to examine the potential allelopathic impact of an invasive non-native shrub/tree on multiple plant species using field observation and experimental allelopathy studies. We surveyed and collected an invasive, non-native tree/shrub (Rhamnus cathartica) at Tifft Nature Preserve (a 107-ha urban natural area near Lake Erie in Buffalo, NY). We also surveyed understory plant communities in the urban forest to examine correlations between R. cathartica abundance and local plant community abundance and richness. We then used experimental mesocosms to test if patterns observed in the field could be explained by adding increased dosages of R. cathartica to soils containing five plant species, including native and non-native woody and herbaceous species. In the highly invaded urban forest, we found that herbaceous cover, shrubs and woody seedlings negatively covaried with R. cathartica basal area and seedlings density. In the mesocosm experiments, R. cathartica resulted in significant decreases in plant community species richness, abundance, and shifted biomass allocation from roots. Our results provide evidence that R. cathartica is highly allelopathic in its invaded range, that R. cathartica roots have an allelopathic effect and that some plant species appear immune. We suggest that these effects may explain the plant’s ability to form dense monocultures and resist competitors, as well as shift community composition with species-specific impacts. 相似文献
2.
The natural expansion of forestry trees into habitats outside plantations is a concern for managers and conservationists. We studied seedling emergence and survival of the two main forestry species in Portugal: Eucalyptus globulus (exotic) and Pinus pinaster (native); using a seed addition experiment. Our main objective was to evaluate the combined effects of climate (mild-summer and warm-summer climate), habitat (oak forest and shrubland), and disturbance (vegetation removal and non-disturbance) on the seedling establishment of species in semi- and natural habitats. Furthermore, we tested the effect of the “sowing season” (autumn and spring) on seedling emergence and survival. Overall, seedling establishment of both species was enhanced by light and water. However, we found important interactions among climate, habitat, and disturbance on both species’ emergence and survival. The differences between habitats were more evident in the mild-summer climate than in the warm-summer climate. Our results also suggested that seedling survival may be enhanced by shrub cover in drier conditions (warm-summer climate). Eucalyptus globulus appears more sensitive to drought and disturbance changes than P. pinaster. In shrublands and mild-summer climate conditions, disturbance especially promoted E. globulus seedling establishment, while the forest canopy and the shade appeared to control it in both climatic conditions. After the first summer life, very low seedling survival was observed in both species, although the colonization of new areas appeared to be more limited for E. globulus. Our study suggests that climate conditions influence the effect (direction and intensity) of habitat and disturbance (plant–plant interactions) on seedling survival. Thus, the effect of light availability (forest canopy) and disturbance (vegetation removal) on these species establishment is climate context-dependent. This study presents very useful information to understand future shifts in these species distribution and has direct applications for the management of natural establishment outside the planted areas, and the management of the understorey to favor forest regeneration or limit forest colonization. 相似文献
3.
Timothy M. Eppley Michela Balestri Marco Campera Johny Rabenantoandro Jean-Baptiste Ramanamanjato Faly Randriatafika Jörg U. Ganzhorn Giuseppe Donati 《International journal of primatology》2017,38(2):338-357
Primate responses to habitat alteration vary depending on the species’ dietary guild and forest type. Leaves from secondary vegetation can provide nutritious resources to folivorous primates, whereas frugivores, burdened with a scattered spatial and temporal distribution of fruiting resources, require larger home ranges, potentially limiting their ability to cope with altered landscapes. Within coastal southeastern Madagascar, we sought to determine whether two lemur species occupying contrasting ecological niches respond differently to the changing features of their degraded and fragmented habitat. We conducted behavioral observations between 2011 and 2013 on frugivorous collared brown lemurs (Eulemur collaris) and folivorous southern bamboo lemurs (Hapalemur meridionalis). To estimate the ability of lemurs to use pioneer species, we categorized all plants used for feeding and resting as fast growing, mid-growing, or slow growing. We fitted general linear mixed-effects models, one for each plant growth category with monthly proportional use rates as the dependent variable, and included species (E. collaris and H. meridionalis), activity (feeding and resting), and season (dry and wet) as fixed effects. Our results show that E. collaris used both slow- and mid-growing plant species most often, while H. meridionalis were more likely to use fast-growing plants, which indicated an ability to use secondary/disturbed vegetation. Frugivorous E. collaris appear more limited by climax plants, while folivorous H. meridionalis appear to be slightly more adaptable, a finding that is consistent with that for other primate folivores. 相似文献
4.
Katherine M. Laushman Sara C. Hotchkiss Bradley M. Herrick 《Biological invasions》2018,20(7):1671-1685
Because Upper Midwest temperate forests lack native earthworms, the invasions of European and Asian earthworms can significantly alter soils and understory vegetation. Earthworms’ ability to increase leaf litter decay, alter nutrient cycling by mixing the organic layer with mineral soil, and decrease plant species richness leads to concern about the Asian ‘jumping earthworm’ (Amynthas agrestis and A. tokioensis) species that were recorded in the University of Wisconsin—Madison Arboretum in 2013. In 2015, we found A. agrestis and A. tokioensis in a distinct 8-ha region of a 23-ha hardwood forest surveyed in the Arboretum; by 2016 A. agrestis and A. tokioensis had spread over an additional 7 ha. Plots also contained the European earthworm species Lumbricus terrestris, L. rubellus, and Apporectodea spp., whose distributions decreased from 2015 to 2016. While leaf litter, plant species richness, and tree and shrub seedling abundance were generally reduced in areas with European earthworms, they were typically slightly increased in areas with A. agrestis and A. tokioensis versus those without. Although our results do not show substantial impacts of A. agrestis and A. tokioensis on vegetation in the initial years of invasion, the rapid replacement of European earthworms by A. agrestis and A. tokioensis suggests continued monitoring of these new invasive species is important to better understand their potential to change the Upper Midwest’s forests. 相似文献
5.
Siddharth Bharath Iyengar Sumanta Bagchi Deepak Barua Charudutt Mishra Mahesh Sankaran 《Plant Ecology》2017,218(7):843-854
Plant communities are structured by both competition and facilitation. The interplay between the two interactions can vary depending on environmental factors, nature of stress, and plant traits. However, whether positive or negative interactions dominate in regions of high biotic and abiotic stress remains unclear. We studied herbaceous plant communities associated with a dwarf shrub Caragana versicolor in semi-arid, high altitude Trans-Himalayan rangelands of Spiti, India. We surveyed 120 pairs of plots (within and outside shrub canopies) across four watersheds differing in altitude, aspect, and dominant herbivores. Herbaceous communities within shrub canopies had 25% higher species richness, but similar abundance when compared to communities outside the canopy, with the shrub edge having higher diversity than the centre of the canopy. Grasses and erect forbs showed positive associations with the shrub, while prostrate plants occurred at much lower abundance within the canopy. Rare species showed stronger positive associations with Caragana than abundant species. Experimental removal of herbaceous vegetation from within shrub canopies led to 42% increase in flowering in Caragana, indicating a cost to the host shrubs. Our study indicates a robust pattern of a dwarf shrub facilitating local community diversity across this alpine landscape, increasing diversity at the plot level, facilitating rare species, and yet incurring a cost to hosts from the presence of herbaceous plants. Given these large influences of this shrub on the vegetation of these high altitude rangelands, we suggest that the shrub microhabitat be explicitly considered in any analyses of ecosystem health in such rangelands. 相似文献
6.
A. V. Fateryga 《Entomological Review》2018,98(3):283-289
The bionomics of Leptochilus membranaceus (Morawitz) was studied in Crimea. The species is confined to herbaceous xerophytic habitats with sparse vegetation and has two generations per year. Adult feeding was recorded on flowers of 8 plant species of 6 families. A single nest was found in an old acridid egg pod in clayey soil. The inner cavity of the empty egg pod was 12 mm long and 3 mm wide. The nest contained one cell with a prepupa in the cocoon. The cell was sealed with a final plug 2 mm thick, made of gravel and mud. The cocoon consisted of three equal thin layers, the outer layer being firmly attached to the cell walls. Females of L. membranaceus do not visit water sources. The origin of the agent bonding the building material (soil) used by L. membranaceus and other congeneric species is discussed. In addition, nests of Ancistrocerus scoticus (Curtis) are also discussed; these nests occur in old acridid egg pods which were earlier misinterpreted as bottle-shaped cells built by the wasps themselves. 相似文献
7.
S. V. Stukalyuk 《Entomological Review》2017,97(3):320-343
Investigations were carried out in June–August 2012 and 2013 in broadleaf forests and planted stands of the northern red oak Quercus rubra in Kiev. The ant visitation rates of 3–6 most abundant plant species within each vegetation layer were analyzed. In all, 16 species of ants were found in the broadleaf forest (Quercus robur + Acer spp. + Carpinus betulus), with the dominance of three species: Formica rufa, Lasius fuliginosus, and L. emarginatus. Eight ant species occurred in Q. rubra stands with the undergrowth of Acer campestre and A. platanoides; the dominant species were Lasius fuliginosus and L. emarginatus. The northern red oak stands with conspecific undergrowth had only four ant species with no dominants among them. Plants with the highest ant visitation rates in the herbage layer of the broadleaf forest were the invasive Impatiens parviflora and the native Aegopodium podagraria. Ants were rare or absent on the remaining herbs: Impatiens noli-tangere, Carex sylvatica, Stellaria holostea, and Galium odoratum. The herbage layer was mostly visited by influents, the dominants being represented only by Lasius emarginatus. Within the shrub layer, ants most frequently visited the undergrowth of the maple Acer platanoides, often harboring colonies of the aphid Periphyllus lyropictus; the highest visitation rates were recorded in the dominants L. emarginatus and L. fuliginosus. The arboreal layer had the highest visitation rate and was most often visited by the dominants Lasius fuliginosus, L. emarginatus, and F. rufa. The common oak Q. robur was the most visited tree in broadleaf forests. In addition to providing ants with food (colonies of the aphids Lachnus roboris and Stomaphis quercus, and also phytophagous insects and other invertebrates), these trees were used for nesting by the dominants L. fuliginosus and L. emarginatus. The presence of aphid colonies was also typical of ripe trees and undergrowth of the maple A. platanoides, the second-visited tree in broadleaf forests. The common hornbeam Carpinus betulus was the least frequently visited, though some ant species, usually L. emarginatus, nested in the trunks and branches of old trees. The vertical distribution of ants in broadleaf forests and red oak stands formed two clusters: the influents occupied the lower (herbage and shrub) vegetation layers, while the subdominants and dominants occupied the upper (shrub and arboreal) ones. The smallest number of ant species (1 or 2) in all the vegetation layers was recorded in the areas with F. rufa; areas with L. fuliginosus had twice as many species; the greatest numbers of ant species were found in the areas with L. emarginatus and in those without dominants. This pattern may result from different territoriality of the dominants: the strongest in F. rufa (defending the whole territory) and the weaker in the other two species (defending only a part of the territory). Plants of all the vegetation layers varied in their attractiveness to ants. As a result, the layers had a mosaic structure in their vertical (between-layer) and horizontal (between different plant species within one layer) arrangement. From 60 to 100% of plants of certain species were visited by ants while plants of other species were not visited at all. The main reason for visiting plants by ants was the presence of aphid colonies. 相似文献
8.
An invasion of non-native plant species represents the most serious environmental problem threatening the biodiversity and changing the nature of the landscape. A chemical elimination is one of the methods used to fight neophytes. It was carried out in the study area of the Morávka River flowing beneath the Beskydy Mountains between 2007 and 2010. The elimination of Reynoutria spp. was implemented as a part of the ‘Preservation of alluvial forest habitats in the Morávka River basin’ project. The population of the invasive neophyte Reynoutria spp. was eliminated by using a combination of mechanical and chemical treatment. Roundup Biaktiv herbicide was used for the chemical elimination. We investigated the consequences of the areal chemical elimination of Reynoutria spp. on the herbaceous undergrowth of the forest of the alluvium of the Morávka River. A multivariate analysis was employed to examine responses of the spring herbaceous plant species and native and non-native summer plant species composition to the chemical treatment. The hypothesis that consequences of the chemical elimination are not reflected in the spring plant species composition, whereas the applications of the herbicide and their frequency is one of crucial factors for the variability of the summer plant species composition was confirmed. The chemical elimination affected plant species composition of the non-native plant species more significantly than the plant species composition of the native plant species. A higher frequency of herbicide application caused increased diversity of both native and non-native plant species, although more noticeably in the case of the latter ones. 相似文献
9.
Lia A. Russek Carolina L. Mansilla Silvio J. Crespin Javier A. Simonetti Audrey A. Grez 《Journal of Insect Conservation》2017,21(5-6):943-950
The replacement of native forests by Pinus radiata plantations modifies habitat availability and quality for wildlife, constituting a threat to species survival. However, the presence of understory in mature pine plantations minimizes the negative impacts of native forest replacement, rendering a secondary habitat for wildlife. Whether forest-dwelling species recolonize clear-felled areas pending on the spontaneous development of accompanying vegetation growing after harvesting is yet to be assessed. In this context, we analyze the abundance, movement and habitat selection of the endemic ground beetle Ceroglossus chilensis (Coleoptera: Carabidae) in an anthropic forest landscape consisting of native forest remnants, adult pine plantations (>?20 years) with a well-developed understory, and young (1–2 years) pine plantations with varying degrees of accompanying vegetation development. Particularly, we analyze the likelihood that C. chilensis would recolonize young pine plantations depending on the presence (>?70% cover) or the absence (<?20% cover) of this accompanying vegetation. C. chilensis shows a greater probability of selecting habitats with understory (pine plantations and native forest) and young plantations with accompanying vegetation (future understory) than habitats without such vegetation. Movement of C. chilensis also favors their permanence in habitats with understory vegetation, coinciding with higher abundances than in young pine plantations devoid of accompanying vegetation. Hence, the effect of clearcutting could be mitigated by allowing the development of accompanying vegetation into a future understory, which facilitates the recolonization of pine plantations and its use as secondary habitat for wildlife. 相似文献
10.
Alberto Maceda-Veiga Helena Basas Gerard Lanzaco Miquel Sala Adolfo de Sostoa Antoni Serra 《Biological invasions》2016,18(3):731-749
Riparian areas have experienced long-term anthropogenic impacts including the effects of plant introductions. In this study, 27 plots were surveyed across three Mediterranean rivers in north-eastern Spain to explore the effects of the invader giant reed (Arundo donax) on riparian habitat features and the diversity, trophic structure, body size, and abundances of epigeal and hypogeal arthropods in riparian areas. Using pitfall traps and Berlese funnels, this study detected a significant increase in collembola abundance and a decrease in the abundance, body size and diversity of macro-arthropods at order and family levels in invaded plots compared to native stands. Invaded and un-invaded areas also differed in the taxonomical structure of arthropod assemblies but not in trophic guild proportions. However, the fact that arthropods were smaller in A. donax soils, together with the absence of particular taxa within each trophic guild or even an entire trophic group (parasitoids), suggests that food-web alterations in invaded areas cannot be discarded. Habitat features also differed between invaded and un-invaded areas with the poorest herbaceous understory and the largest leaf litter deposition and soil carbon stock observed in A. donax plots. The type of vegetation in riparian areas followed by the total native plant species richness were identified as major causal factors to changes in the abundance, diversity and composition of macro-arthropods. However, our analyses also showed that some alterations related to A. donax invasion were inconsistent across rivers, suggesting that A. donax effects may be context dependent. In conclusion, this study highlights an impoverishment of native flora and arthropod fauna in A. donax soils, and suggests major changes in riparian food webs if A. donax displaces native riparian vegetation. 相似文献
11.
Coniferous forests are a significant feature in the natural vegetation of the Mediterranean mountains, but most stands are rather degraded and the present distribution is just a fraction of its potential natural area. The Parnonas range (Peloponnese, Greece) ranks among the most extensive areas with a well-preserved mountain coniferous forest in the Mediterranean. The present paper aims at describing the conifer-dominated vegetation of this mountain and the ecological roles of the prevailing speciesAbies cephalonica, Pinus nigra, andJuniperus drupacea. For comparison, a survey is provided of theAbies cephalonica forests in the total distribution area, using all published relevés. Species composition and abundance, together with structural and abiotic parameters were recorded in 118 relevés distributed throughout Mt. Parnon. The phytosociological classification reveals 8 interpretable vegetation types well separated by groups of diagnostic species and presented in a synoptic table. The ecology and distribution of the units are outlined, and they are assigned to 4 associations within theAbietion cephalonicae (Helictotricho convoluti-Abietetum cephalonicae, Junipero drupaceae-Abietetum cephalonicae, Lilio chalcedonicae-Abietetum cephalonicae, Pyrolo chloranthae — Pinetum nigrae). The syntaxonomy and nomenclature of these associations, two of which are described as new, are discussed. The most important gradients in the data matrix found by detrended correspondence analysis (DCA) are related to altitude/climate and rockiness/soil. The communities are well segregated in the ordination space, and the fairly distinct clusters of the three conifer species are discussed. These conifers may be arranged along a gradient of decreasing drought tolerance fromJuniperus throughAbies toPinus. The latter is predominant and most vital essentially on schistose soils, or else reflects previous disturbance by, e.g., wildfires.Juniperus drupacea is a subordinate low tree or shrub in Tripolitza limestoneAbies forest. The vitality ofAbies cephalonica as expressed by tree height and structure is best in theLilio-Abietetum, between 1300 and 1600 m. The community variation within the total area of theAbietion cephalonicae reflects a principal differentiation in xerophytic and mesophytic stands. This pattern is encountered in various mountains and suggests that water supply is the crucial factor governing the floristic variation in the mountain coniferous forests. 相似文献
12.
Since the mid-2000s, the exotic coccinellid species Harmonia axyridis (Pallas) has established itself in Northern Italy, raising serious concerns about possible repercussions on native ladybirds. In this study we compared the ladybird assemblages in 2015–2016 with those sampled in 1995–1996, before the arrival of H. axyridis. Surveys were carried out in the same sites and with the same methods for both periods. Aphidophagous ladybirds were sampled in hedgerows and herbaceous habitats at field margins by mechanical knockdown and sweeping net, respectively. The changes in the structure of ladybird communities after the arrival of H. axyridis were significantly different between arboreal and herbaceous habitats. Harmonia axyridis is currently the dominant species in shrubs and trees, and all the native ladybird species taken together account for only approximately one third of the total individuals sampled in 2015–2016. On the other hand, the relative abundance of the exotic species in herbaceous habitats was low, and it has had a negligible relevance on the structure of ladybird communities on grasslands. Among native species, Adalia bipunctata (L.), whose ecological niche largely overlaps with that of H. axyridis, suffered the largest decline between 1995–1996 and 2015–2016. The co-occurrence of H. axyridis invasion and the regression of A. bipunctata suggest a direct impact of the exotic species, because no other major modifications occurred in the studied areas between sampling periods. 相似文献
13.
M. Cristina MacSwiney G. Beatríz Bolívar-Cimé Rita Alfaro-Bates J. Javier Ortíz-Díaz Frank M. Clarke Paul A. Racey 《Acta theriologica》2017,62(2):189-193
Artibeus jamaicensis is a medium-sized frugivorous microchiropteran bat that complements its diet with nectar and pollen during the dry season. We investigated which species of pollen are carried by A. jamaicensis in order to determine its potential role as a plant pollinator in the northern Yucatan Peninsula. We collected pollen from the fur of 192 individuals throughout the year from April 2004 to March 2005. We recorded pollen from nine plant species of eight families and found five unidentified pollen types, with the highest pollen species richness recorded in June. A. jamaicensis moved pollen of Erythrina standleyana and Mimosa bahamensis, which have not hitherto been reported as visited by this species. The most abundant pollen in the samples was found to be that of three tree species: Ceiba pentandra, C. aesculifolia and Lysiloma latisiliquum. Very few samples contained pollen in the rainy season, when the bats fed mainly on fruits. A. jamaicensis can fly several kilometres among foraging locations and dispersed large amounts of pollen from tree species growing near cenotes as well as those not present at cenotes but occurring in other forest fragments, highlighting its importance as a pollen vector among forest fragments in the largely deforested landscape of the Yucatan Peninsula, helping to reduce the negative effects of forest fragmentation. Ceiba appears to benefit from the role of A. jamaicensis as a pollen vector, and the species play an important ecological role in the Yucatán landscape, supplying shade, nectar and fruit for wildlife. 相似文献
14.
To examine the effects of soil fertility on biomass production, plant species diversity, and early vegetation development, we performed a mesocosm experiment using soil seed bank under three soil fertility levels (ombrotrophic, mesotrophic, and eutrophic). Biomass production linearly increased (P < 0.01), whereas plant species diversity significantly decreased (P < 0.001) as soil fertility increased. Soil fertility seemed to play a role as an environmental sieve in early vegetation development, in turn, lead the patterns of biomass production and plant species diversity. Several Poaceae species which are forming tall and dense canopy, such as Phalaris arundinacea, Miscanthus sacchariflorus, and Zizania latifolia, showed higher importance values under fertilized condition, whereas relatively small macrophytes of Eleocharis acicularis, Carex dickinsii, and Isachne globosa mainly survived under ombrotrophic condition. Although plant species richness decreased as soil fertility increased, the percentages of perennials and exotics increased rather than annuals and natives. Predominance of perennials and exotics under eutrophic condition in early vegetation development seemed to lead a continuous decrease in plant species diversity as a result of competitive effect. A significant negative relationship between plant species diversity and biomass production (P < 0.0001) was obtained when all experimental plots are included in correlation analysis. 相似文献
15.
M L C Rocha P F Cristaldo J S Cruz J J M Sacramento D V Ferreira A P A Araújo 《Neotropical Entomology》2018,47(6):750-756
Symbiosis between plants and ants include examples in which the plant provides shelter and/or food for ants that, in turn, act in the defense or in the dispersion of seeds from the host plant. Although traditionally referred as mutualistic, the results of these interactions may vary with the ecological context in which patterns are involved. A range of species have facultative association with Turnera subulata (Turneraceae). Here, using behavioral bioassays, we investigated the effects of the most frequent ant species associated with T. subulata (Brachymyrmex sp.1, Camponotus blandus (Smith), Dorymyrmex sp.1, Crematogaster obscurata Emery, and Solenopsis invicta Buren) in the dispersion of plant host seeds and in the number of seedlings around the associated ant nests. We also evaluated the effects of these ant species in the germination of T. subulata seeds, in the consumption of elaiosome, and in the attractiveness to elaiosome odor. Our results showed that the ant species associated with T. subulata presented variation in the attraction by the odor and in the rate of consumption of the elaiosomes. However, none of the ant species studied contributed significantly to the increase of seed germination and seedling growth. Our results suggest that the consumption of the elaiosome by ant species is not a determinant factor to the success of germination of T. subulata. However, such species could contribute indirectly to seed germination by carrying seeds to sites more fertile to germination. In general, our results help to elucidate the results of ecological interactions involving ants and plants. 相似文献
16.
Ayub M. O. Oduor Huaping Long A. Belarmain Fandohan Jian Liu Xiubo Yu 《Biological invasions》2018,20(10):2745-2751
Invasion by exotic plant species and herbivory can individually alter native plant species diversity, but their interactive effects in structuring native plant communities remain little studied. Many exotic plant species escape from their co-evolved specialized herbivores in their native range (in accordance with the enemy release hypothesis). When these invasive plants are relatively unpalatable, they may act as nurse plants by reducing herbivore damage on co-occurring native plants, thereby structuring native plant communities. However, the potential for unpalatable invasive plants to structure native plant communities has been little investigated. Here, we tested whether presence of an unpalatable exotic invader Opuntia ficus-indica was associated with the structure of native plant communities in an ecosystem with a long history of grazing by ungulate herbivores. Along 17 transects (each 1000 m long), we conducted a native vegetation survey in paired invaded and uninvaded plots. Plots that harboured O. ficus-indica had higher native plant species richness and Shannon–Wiener diversity H′ than uninvaded plots. However, mean species evenness J was similar between invaded and uninvaded plots. There was no significant correlation between native plant diversity and percentage plot cover by O. ficus-indica. Presence of O. ficus-indica was associated with a compositional change in native community assemblages between paired invaded and uninvaded plots. Although these results are only correlative, they suggest that unpalatable exotic plants may play an important ecological role as refugia for maintenance of native plant diversity in intensely grazed ecosystems. 相似文献
17.
Forest Type Influences Population Densities of Nocturnal Lemurs in Manompana,Northeastern Madagascar
Alex Miller Harriet Mills Tantely Ralantoharijaona Nicole Andriaholinirina Volasoa Chantal Misandeau Lounès Chikhi Roberta Bencini Jordi Salmona 《International journal of primatology》2018,39(4):646-669
Forest loss, fragmentation, and anthropization threaten the survival of forest species all over the world. Shifting agriculture is one of these threatening processes in Madagascar. However, when its cycle is halted and the land is left to regenerate, the resulting growth of secondary forest may provide a viable habitat for folivorous and omnivorous lemur species. We aimed to identify the response of nocturnal lemurs to different successional stages of regenerating secondary, degraded mature, and mature forest across a mosaic-type landscape. We surveyed four nocturnal lemur species (Avahi laniger, Microcebus cf. simmonsi, Allocebus trichotis, and Daubentonia madagascariensis) in four forest types of varying habitat disturbance in northeastern Madagascar. We estimated densities in mature and regenerating secondary forest for the eastern woolly lemur (Avahi laniger) and mouse lemur (Microcebus cf. simmonsi), two sympatric species with folivorous and omnivorous diets respectively. We did not estimate densities of Allocebus trichotis and Daubentonia madagascariensis owing to small sample size; however, we observed both species exclusively in mature forest. We found higher population densities of A. laniger and M. cf. simmonsi in secondary than in mature forest, showing the potential of regenerating secondary forest for lemur conservation. Several environmental factors influenced the detectability of the two lemur species. While observer and habitat type influenced detection of the eastern woolly lemur, canopy height and vine density influenced detection of mouse lemurs. Understanding how different species with different diets interact with anthropogenically impacted habitat will aid future management decisions for the conservation of primate species. 相似文献
18.
We compared species composition and diversity of the soil seed and seedling banks in three secondary vegetation types (shrubland, Populus bonatii forest, Lithocarpus regrowth forest) and a primary old-growth forest in the subtropical Ailao Mountains of southwestern China to clarify the importance of seed and seedling banks for forest dynamics. The average species richness was the highest in soil samples from the shrubland (26.80 ± 1.98), and the lowest from the primary forest (9.93 ± 0.50). The density of germinable tree seeds increased from the secondary vegetation to the primary forest, and the density of shrub, forb, and graminoid seeds decreased significantly. The most abundant seedlings recorded in soil samples were light-demanding species in the shrubland and Populus bonatii forest. For ground flora, the number of shrub seedlings strongly decreased with the increase in stand age, and shade-tolerant tree seedlings tended to increase. The species similarity between the seed bank and the aboveground vegetation in all sites was low (Sørensen’s index = 0.11–0.33), however, the shrubland had higher similarity compared with the other three plant communities. In the primary forest, light-demanding woody species dominated in soil seed banks, while shade-tolerant species dominated in the overstory and the forest floor. In the primary forest, seedlings of dominant tree species were rare in the understory, and no seeds of the dominant species were found in the soil. Results indicated that the early stages of vegetation recovery should take into account the possibility of recovering soil seed bank processes. However, colonization and establishment of tree seedlings will be difficult once a primary forest is destroyed. 相似文献
19.
Plant communities in which the herb layer is dominated by Vellozia crinita were surveyed in seven mountain ranges with a complex comprising open herbaceous or savanna-like montane vegetation overlying quartzite and sand, locally known as “campos rupestres” in the State of Minas Gerais, southeastern Brazil, by means of 92 vegetation relevés (totaling approx. 4629 m2). Vellozia crinita displayed a growth strategy which is rare among the Velloziaceae south of the Espinhaço mountain chain.While most species of Vellozia are phanerophytes with erect caudices and grow exclusively on or among rock outcrops, V. crinita is a caespitose chamaephyte with a profusely branched, repent caudex which grows under the ground or very slightly exposed. It forms cushions which stabilize convex mounds of colluvial sand, thus occupying a distinct niche in the “campos rupestres”. One association, two subassociations and two variants of the white-sand vegetation component are described as new. 相似文献
20.
The composition of dipterans inhabiting fieldfare nests in a big city was studied for the first time, based on material collected soon after chick fledging. Larvae of 21 species belonging to 14 families were found, including saprophages, necrophages, and predators (Scatopsidae, Ceratopogonidae, Phoridae, Chloropidae, Anthomyiidae, etc.), and also Protocalliphora azurea (Fallén, 1816) (Calliphoridae) and Neottiophilum praeustum (Meigen, 1826) (Neottiophilidae) known as bloodsucking ectoparasites of nestlings. Larvae of P. azurea (up to 121 per nest) were found in both early (April–May) and late (May–June) nests. Larvae of N. praeustum (up to 299 per nest) were recorded only in late nests. The two species occurred both separately and jointly in one nest, with N. praeustum dominating numerically. The seasonal differences in the development of these two parasitic species may account for their high abundance in such ephemeral habitats. Larvae of Trypocalliphora braueri (Hendel, 1901), a subcutaneous parasite of nestlings of many bird species, were not found in the fieldfare nests. A key to the larvae of the three fly species parasitizing nestlings in European Russia is given. 相似文献