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1.
The conservation of hyperdiverse taxa such as arthropods may prove frustrating for land managers who lack the taxonomic expertise to perform species-level identifications. Therefore, interest has turned towards selecting indicator taxa that can be monitored as surrogates for detecting changes in entire communities. In this study, we examined whether several moth families or subfamilies were significant indicators of lepidopteran species richness and habitat disturbance in Eastern deciduous forests of North America. We screened moth families to identify assemblages that are easily sampled and primarily comprised of species that can be identified by non-experts. Using existing field data collected over 3 years, we tested four taxa that met our initial requirements with regard to their performance as an indicator of total observed lepidopteran species richness and levels of forest disturbance. We determined that the Arctiidae and Notodontidae hold promise as potential indicator taxa in Eastern deciduous forests. The Arctiidae functioned best as an indicator of moth species richness, while the Notodontidae performed best as a coarse-scale disturbance indicator. Additional research will be required, however, before species within either family have practical significance as tools for assessing forest condition. 相似文献
2.
In many parts of the world’s forests, intensive management has resulted in habitat loss for several species. Among these, specialised woodpeckers (Aves: Picidae) have been affected negatively due to their high requirements for resources that are scarce in managed forests. We used the gradient of anthropogenic impact on forests in northern Europe’s Baltic Sea region to (1) assess the relationship between the presence of four focal woodpecker species and forest naturalness and (2) quantify their requirements regarding specific resources in four different areas (south-central Sweden, southern Sweden, Lithuania and northeastern Poland). This study focused on specialised woodpecker species of the Dendropicini tribe: the three-toed (Picoides tridactylus), middle spotted (Dendrocopos medius), white-backed (Dendrocopos leucotos) and lesser spotted (Dendrocopos minor) woodpeckers. The occurrence of these species in landscape units of 100 ha was generally related positively to the degree of forest naturalness and to the amounts of resources considered critical for the suitability of their respective habitats. For the middle spotted woodpecker, basal areas 1.0 m2/ha of large-diameter deciduous trees (DBH 40 cm) were associated with a high probability of occurrence (0.9). For the white-backed woodpecker, the same probability of occurrence was found for basal areas 1.4 m2/ha of deciduous snags (DBH 10 cm). Relationships between the occurrence of the three-toed and lesser spotted woodpeckers and snag abundance were more variable among study areas. The results suggest that specialised woodpeckers would benefit from an increase in the area of forest with natural properties. Moreover, they allow defining tentative quantitative targets for sustainable forest management. 相似文献
3.
Barbara?Stempfhuber Tim?Richter-Heitmann Lisa?Bienek Ingo?Sch?ning Marion?Schrumpf Michael?Friedrich Stefanie?Schulz Michael?Schloter
In this study, we investigated how co-occurrence patters of ammonia and nitrite oxidizers, which drive autotrophic nitrification, are influenced by tree species composition as well as soil pH in different forest soils. We expected that a decline of ammonia oxidizers in coniferous forests, as a result of excreted nitrification inhibitors and at acidic sites with low availability of ammonia, would reduce the abundance of nitrite-oxidizing bacteria (NOB). To detect shifts in co-occurrence patterns, the abundance of key players was measured at 50 forest plots with coniferous respectively deciduous vegetation and different soil pH levels in the region Schwäbische Alb (Germany). We found ammonia-oxidizing archaea (AOA) and Nitrospira-like NOB (NS) to be dominating in numbers over their counterparts across all forest types. AOA co-occurred mostly with NS, while bacterial ammonia oxidizers (AOB) were correlated with Nitrobacter-like NOB (NB). Co-occurrence patterns changed from tight significant relationships of all ammonia and nitrite oxidizers in deciduous forests to a significant relationship of AOB and NB in coniferous forests, where AOA abundance was reduced. Surprisingly, no co-occurrence structures between ammonia and nitrite oxidizers could be determined at acidic sites, although abundances were correlated to the respective nitrogen pools. This raises the question whether interactions with heterotrophic nitrifiers may occur, which needs to be addressed in future studies. 相似文献
4.
Woodpeckers (family Picidae) show promise as indicators of avian diversity in forests because their populations can be reliably monitored, and their foraging and nesting activities can positively influence the abundance and richness of other forest birds. A correlation between woodpecker richness and richness of forest birds is known to exist at the landscape scale, but uncertainty remains whether this correlation occurs at the smaller stand-level spatial scales where forest management activities take place. We used data collected under a diverse range of forest types, harvest treatments, and forest health conditions during a long-term study of bird communities in interior British Columbia, Canada, to examine two basic questions: (1) at the level of individual forest stands, is woodpecker richness correlated with bird richness (measured as richness of all other bird species)? and (2) do woodpecker richness and bird richness have similar habitat correlates? Bird richness was positively correlated with woodpecker richness (β = 0.59, SE = 0.22, 95% CI = [0.14 1.03]). Richness of both woodpeckers and all other birds were positively correlated with tree species richness and negatively correlated with density of pines, and the effect for forest harvest type was similar for both measures of avian richness (uncut < partial harvest < clearcut with reserves). The effect of density of lodgepole pines killed by mountain pine beetles differed between the two richness measures, being positive for woodpecker richness and negative for forest bird richness. We conclude that the richness of woodpeckers is indeed correlated with the richness of other birds at the stand-level, and can serve as a reliable indicator of overall bird richness in most forest stands and conditions, except during insect outbreaks when differential responses by woodpeckers and the rest of the avian community may decouple the relationship between bird richness and woodpecker richness. 相似文献
5.
Mycetophilids is a species-rich insect group for which the ecological requirements in temperate forests are poorly understood. This study of mycetophilids was based on trap samples from 15 oak-dominated sites in the boreonemoral zone of southern Sweden. Species richness and composition were analysed in relation to environmental variables at a local and at larger scales (multiple regression), and compared to results from similar studies in spruce-dominated sites in the boreal zone of Norway (PCA and two-sample t tests). Regressions showing a dominance of regional factors over local in-site variables agree with species-richness models assuming that local communities most often are unsaturated. Precipitation (inter-correlated with elevation) was the strongest factor for explaining the variation in species-richness, which is consistent with previous results indicating that mycetophilids are disfavoured by drought. In addition to precipitation, the area of mixed forest with high biodiversity values (woodland key habitats and protected areas) was a positive factor for species-richness, probably because such habitats combine elements of both coniferous and deciduous forests. PCA ordination revealed a clear separation of the species composition between boreal and boreonemoral forests. Species-richness in boreal forest was significantly higher than in boreonemoral forest, indicating a preference for boreal habitats in many of the species. For mycetophilids and other drought-sensitive insects, it is suggested that (partial) cutting in some dense successional oak stands should be avoided, and that some invading spruces should be tolerated. 相似文献
6.
Chile has more than half of the temperate forests in the southern hemisphere. These have been included among the most threatened eco-regions in the world, because of the high degree of endemism and presence of monotypic genera. In this study, we develop empirical models to investigate present and future spatial patterns of woody species richness in temperate forests in south-central Chile. Our aims are both to increase understanding of species richness patterns in such forests and to develop recommendations for forest conservation strategies. Our data were obtained at multiple spatial scales, including field sampling, climate, elevation and topography data, and land-cover and spectrally derived variables from satellite sensor imagery. Climatic and land-cover variables most effectively accounted for tree species richness variability, while only weak relationships were found between explanatory variables and shrub species richness. The best models were used to obtain prediction maps of tree species richness for 2050, using data from the Hadley Centre’s HadCM3 model. Current protected areas are located far from the areas of highest tree conservation value and our models suggest this trend will continue. We therefore suggest that current conservation strategies are insufficient, a trend likely to be repeated across many other areas. We propose the current network of protected areas should be increased, prioritizing sites of both current and future importance to increase the effectiveness of the national protected areas system. In this way, target sites for conservation can also be chosen to bring other benefits, such as improved water supply to populated areas. 相似文献
7.
Landscape supplementation in adjacent savannas and its implications for the design of corridors for forest birds in the central Cerrado, Brazil 总被引：1，自引：0，他引：1
We examined landscape supplementation (sensu [Oikos 65 (1992) 169]) by forest birds along forest/savanna boundaries in central Brazil to: (1) verify the role of savanna vegetation in providing resources to forest bird communities; (2) suggest minimum amounts of savannas to be conserved within corridors, to provide adequate foraging habitat for forest birds outside reserves. Transect counts parallel (n=64) and perpendicular (n=64) to forests were conducted in eight savannas (cerrado sensu stricto) between February 2000 and January 2001. Patterns of species richness and abundance of birds in relation to distances from forests were examined using Generalised Linear Mixed Models. Omnivores were the most abundant birds foraging in savannas, followed by insectivores and frugivores. Landscape supplementation in savannas was proportional to the density of savanna vegetation. Also, it was higher in the breeding season than in the non-breeding period. These two patterns suggest that surrounding savannas play a major role in providing additional foraging areas for forest bird species. We suggest that the environmental policy currently protecting 20 m of gallery forests along each side of rivers be modified to include at least 60 m of savanna along these forests through central Brazil. The study suggests that appropriate conservation efforts should also encompass the surrounding matrix to which the home ranges of target species are expanded, and not only their major habitat. 相似文献
8.
龙门山断裂带主要森林类型凋落物累积量及其持水特性 总被引：2，自引：1，他引：1
采用野外实地调查与室内控制浸提相结合的方法,对龙门山断裂带常绿阔叶林、落叶阔叶林、针阔混交林、常绿针叶林4种森林类型的凋落物储量、持水量、吸水速率进行了研究。结果发现,不同森林类型凋落物总储量大小顺序为:常绿针叶林(8.26t/hm2)落叶阔叶林(6.80t/hm2)针阔混交林(5.52t/hm2)常绿阔叶林(4.61t/hm2),且未分解层累积量所占比例均小于半分解层。不同森林类型不同分解程度凋落物的持水量和持水率与浸泡时间均呈对数关系,其吸水速率与浸泡时间呈幂函数关系。研究区4种森林类型半分解层凋落物的持水能力均强于分解层,而落叶阔叶林和针阔混交林持水能力较强,其次是常绿针叶林,常绿阔叶林最低。研究表明,在该区森林植被恢复和重建过程中,应充分考虑半分解层凋落物对水土保持的作用,且宜优选落叶阔叶林和针阔混交林模式进行森林植被恢复。 相似文献
9.
Luís Reino Pedro Beja Patrick E. Osborne António Fabião 《Biological conservation》2009,142(4):824-838
Afforestation often causes direct habitat losses for farmland birds of conservation concern, but it is uncertain whether negative effects also extend significantly into adjacent open land. Information is thus required on how these species react to wooded edges, and how their responses are affected by edge and landscape characteristics. These issues were examined in Mediterranean arable farmland, using bird counts at 0, 100, 200, 300 and >300 m from oak, pine and eucalyptus edges, embedded in landscapes with variable amounts and spatial configurations of forest plantations. Bird diversity declined away from edges, including that of woodland, farmland and ground-nesting birds. Positive edge responses were also found for overall and woodland bird abundances, and for five of the nine most widespread and abundant species (Galerida larks, stonechat, linnet, goldfinch and corn bunting). Strong negative edge effects were only recorded for steppe birds, with reduced abundances near edges of calandra larks and short-toed larks, but not of little bustards and tawny pipits. Edge contrast affected the magnitude of edge effects, with a tendency for stronger responses to old and tall eucalyptus plantations (hard edges) than to young and short oak plantations (soft edges). There were also species-specific interactions between edge and fragmentation effects, with positive edge responses tending to be strongest in less fragmented landscapes, whereas steppe birds tended to increase faster away from edges and to reach the highest species richness and abundances in large arable patches. Results suggest that forest plantations may increase overall bird diversity and abundance in adjacent farmland, at the expenses of steppe birds of conservation concern. Clustering forest plantations in a few large patches and thus reducing the density of wooded edges at the landscape-scale might reduce such negative impacts. 相似文献
10.
Navjot S. Sodhi Lian Pin Koh Dewi M. Prawiradilaga Idris Tinulele Tommy Han Tong Tan 《Biological conservation》2005,122(4):547-558
Unprecedented deforestation is currently underway in Southeast Asia. Since this trend is likely to continue, it is critical to determine the value of human-modified habitats (e.g., mixed-rural habitat) for conserving the regional native forest avifauna. The impacts of ongoing deforestation on the highly endemic avifauna (33%) of Sulawesi (Indonesia) are poorly understood. We sampled birds in primary and secondary forests in the Lore Lindu National Park in central Sulawesi, as well as the surrounding plantation and mixed-rural habitats. Species richness, species density and population density of forest birds showed a consistent decreasing trend in the following order: primary forests > secondary forests > mixed-rural habitat > plantations. Although primary forests contained the highest proportion (85%) of a total of 34 forest species recorded from our point count surveys, 40-yr old secondary forests and the mixed-rural habitat showed high conservation potential, containing 82% and 76% of the forest species, respectively. Plantations recorded only 32% of the forest bird species. Fifteen forest species had the highest abundance in primary forests, while two species had higher abundance outside primary forests. Our simulations revealed that all forest birds that were sensitive to native tree cover could be found in areas with at least 20% continuous native tree cover. Our study shows that although primary forests have the highest conservation value for forest avifauna, the potential of degraded habitats, such as secondary forests and the mixed-rural habitat, for conserving forest species can be enhanced with appropriate land use and management decisions. 相似文献
11.
Does forest continuity matter in conservation? - A study of epiphytic lichens and bryophytes in beech forests of southern Sweden 总被引：1，自引：0，他引：1
The effects of forest continuity at local scale for red-listed and indicator species of epiphytic lichens and bryophytes were investigated in 150 Fagus sylvatica stands in southern Sweden. Stands having forest continuity (n = 106) had continuous forest cover more than 350 years, whereas stands lacking continuity (n = 44) had forest cover less than 160 years. Forest continuity was identified by comparing a sequence of historical maps with a modern survey of beech forests. In the field woody beech substrates were searched for the epiphytes of interest. A number of environmental and spatial variables were inventoried and compiled for each stand. In all 64 species (51 lichens, 13 bryophytes) were found in the stands having continuity, and 21 (14 lichens, 7 bryophytes) in the stands lacking continuity. Controlling for the different number of surveyed stands, stands having continuity had significantly more species of lichens, but not of bryophytes. In the stands lacking continuity we did not find lichens associated with the very late succession stage. The quantity of substrates, stand age and forest continuity were the three most important factors explaining species richness as well as composition of studied epiphytes. The effect of continuity was probably due to a combination of a higher substrate quality, mainly old beeches, and a longer time available for colonization. Also, we found strong positive correlations between number of indicator and red-listed epiphyte species. In short-term conservation old stands having continuity, containing suitable substrates and indicator species are target areas. 相似文献
12.
Valérie Roy 《Biological conservation》2008,141(1):298-307
The maintenance of connecting habitats such as hedgerows in production landscapes could become increasingly critical as species migration is expected to accelerate with climate change. Species of particular conservation interest that could benefit from connecting habitats especially in agroecosystems are native forest herbs. It is still unclear, however, which hedgerow habitats have the best potential of supporting diverse forest herb communities, making it hard to target particular structures for conservation. Our objective was to identify the local and landscape characteristics of hedgerows that could help predict their potential at maximizing the richness, abundance, and diversity of native forest herbs of temperate deciduous forests of North-East America. We used multiple regression, Moran’I correlograms, and conditional autoregressive models to assess the effect of landscape and historical variables (hedgerow age, amount of adjacent forest cover, connection to forests and other hedgerows) and of local variables (hedgerow width, canopy cover, cover of other species) on the response variables. The results show an increase in forest herb diversity and abundance in hedgerows with time and with increasing nearby forest cover. Local factors such as greater width and reduced cover of other species also relate to a greater abundance and diversity of forest herbs in linear habitats. The fact that forest herb communities can reassemble in hedgerow corridors with time implies that there could be long-term benefits in maintaining and even creating linear habitats where there is a pool of dispersing forest herbs. 相似文献
13.
With an increasing proportion of natural forests being replaced by plantations, there is a need to determine their potential to fulfill ecological purposes other than wood production. This study evaluated the extent to which deciduous and coniferous plantations develop understory attributes comparable to those of naturally regenerated stands. A functional group approach was used to synthesise species responses in terms of their ecological traits. Multivariate analyses of ecological traits revealed 16 emergent groups that shared common traits associated with a similar life history strategy. Responses of these groups, understory structure, and understory environmental conditions to plantation types and stand stages were analyzed and compared to naturally regenerated stands. Clear associations of trait responses to stand developmental stages and plantation types emerged. Light-demanding and wind-dispersed species groups were associated with early-successional stages, while woody groups, ferns and ant-dispersed spring-flowering herbs were associated with late-successional stages. Analyses also revealed an indicator group associated with old naturally regenerated forest. The understory functional groups and environmental conditions of deciduous plantations converged toward those of old naturally regenerated forests. However, understory structure in deciduous plantations remained poorly developed and richness of the indicator group was low compared to unplanted stands. Conifer plantations, currently the most common plantation type in the northern hardwood biome, showed a completely different pathway of understory development. Modifications to current plantation management practices are proposed to help recreate or maintain natural understory biological and physical attributes. 相似文献
14.
Rivers and streams lined by narrow forest strips are common in the lowland countryside of south-western Costa Rica. We studied the importance of these gallery forests for understorey birds, especially forest species. Using mist-nets, we captured 1110 birds belonging to 90 species between June and September 2007 at 16 sites spread equally over four habitat types: forest interior, forest margin, gallery forest connected to closed forest, and isolated gallery forest. Though isolated gallery forests had the greatest number of expected species in total, they supported the lowest number of forest-specialist species, lower even than connected gallery forests. Granivorous birds showed an increase from forest to isolated gallery forest, all other feeding guilds however showed no change. The studied habitats differed from each other in their faunal composition. Assemblages of three species groups categorised by their habitat preferences (forest specialists, forest generalists, non-forest species) showed nested distribution patterns across the four habitats. There was no significant difference in the proportion of birds with brood patches or of recaptures across the studied habitat types, leading to the assumption that birds not only use gallery forests for movement and foraging but also for reproduction. Though of limited conservation value for most forest understorey birds, at least for a small fraction of forest species gallery forests constitute an important secondary habitat. More significantly, they can form corridors or stepping stones that allow movements within the matrix of human-dominated habitats, and represent an important landscape component benefiting total bird species richness in the Costa Rican countryside. 相似文献
15.
Forest fragmentation leads to the creation of isolated forest patches and habitat edges with subsequent impact on forest-interior bird species. Although the effects of fragmentation and edge on avian nesting success are well documented for open cup-nesting species in eastern deciduous forests in North America, it is unclear whether these effects are common for all birds nesting in predominantly forested landscapes. In particular, edge effects on nesting success of cavity-nesting birds are poorly understood. Using natural cavity nests, we examined nesting success of four species of cavity-nesting birds (two nonexcavators and two excavators), the yellow-rumped flycatcher (Ficedula zanthopygia), the great tit (Parus major), the great spotted woodpecker (Picoides major), and the grey-faced woodpecker (Picus canus) in relation to forest edges in Zuojia Nature Reserve, Jilin province, northeastern China. Our primary objective was to assess whether distance to the edge of agricultural lands was related to nesting success for cavity-nesting birds in fragmented forests. A total of 439 natural cavity nests of the four species were located and monitored during four breeding seasons. Probability of nest success was influenced by distance to forest edge for nonexcavators, but not for excavators. The rate of nesting success of the two nonexcavators, yellow-rumped flycatcher and the great tit, increased with distance from the edges. For all cavity nests, nesting success was 0.43 at 0-100 m, 0.56 at 101-200 m, 0.68 at 201-300 m, 0.61 at 301-400 m, 0.77 at 401-500 m from the edges. Nesting success ranged from 0.57 for the yellow-rumped flycatcher to 0.89 for the Grey-faced Woodpecker. Failed nests were often occupied by nest-site competitors (accounting for 68%). However, predation only accounted for 20% of all nest failures. Our results suggest that negative edge effects do exist for some cavity-nesting birds, especially for nonexcavator species. 相似文献
16.
Susan L. Roberts Jan W. van Wagtendonk A. Keith Miles Douglas A. Kelt 《Biological conservation》2011,(1):610-619
The spotted owl (Strix occidentalis) is a late-successional forest dependent species that is sensitive to forest management practices throughout its range. An increase in the frequency and spatial extent of stand-replacing fires in western North America has prompted concern for the persistence of spotted owls and other sensitive late-successional forest associated species. However, there is sparse information on the effects of fire on spotted owls to guide conservation policies. In 2004–2005, we surveyed for California spotted owls during the breeding season at 32 random sites (16 burned, 16 unburned) throughout late-successional montane forest in Yosemite National Park, California. Our burned areas burned at all severities, but predominately involved low to moderate fire severity. Based on an information theoretic approach, spotted owl detection and occupancy rates were similar between burned and unburned sites. Nest and roost site occupancy was best explained by a model that combined total tree basal area (positive effect) with cover by coarse woody debris (negative effect). The density estimates of California spotted owl pairs were similar in burned and unburned forests, and the overall mean density estimate for Yosemite was higher than previously reported for montane forests. Our results indicate that low to moderate severity fires, historically common within montane forests of the Sierra Nevada, California, maintain habitat characteristics essential for spotted owl site occupancy. These results suggest that managed fires that emulate the historic fire regime of these forests may maintain spotted owl habitat and protect this species from the effects of future catastrophic fires. 相似文献
17.
《Pedobiologia》2014,57(4-6):235-244
Vegetation type influences the rate of accumulation and mineralization of organic matter in forest soil, mainly through its effect on soil microorganisms. We investigated the relationships among forest types and microbial biomass C (MBC), basal respiration (RB), substrate-induced respiration (RS), N mineralization (Nmin), specific growth rate μ, microbial eco-physiology and activities of seven hydrolytic enzymes, in samples taken from 25 stands on acidic soils and one stand on limestone, covering typical types of coniferous and deciduous forests in Central Europe. Soils under deciduous trees were less acidic than soils of coniferous forests, which led to increased mineralizing activities RB and Nmin, and a higher proportion of active microbial biomass (RS/MBC) in the Of horizon. This resulted in more extractable organic C (0.5 M K2SO4) in soils of deciduous forests and a higher accumulation of soil organic matter (SOM) in coniferous forest soil. No effect of forest type on the microbial properties was detected in the Oh horizon and in the 0–10 cm layer. The microbial quotient (MBC/Corg), reflecting the quality of organic matter used for microbial growth, was higher in deciduous forests in all three layers. The metabolic quotient qCO2 (RB/MBC) and the specific growth rate μ, estimated using respiration growth curves, did not differ in soils of both forest types. Our results showed that the quality of SOM in coniferous forests supported microorganisms with higher activities of β-glucosidase, cellobiosidase and β-xylosidase, which suggested the key importance of fungi in these soils. Processes mediated by bacteria were probably more important in deciduous forest soils with higher activities of arylsulphatase and urease. The results from the stand on limestone showed that pH had a positive effect on microbial biomass and SOM mineralization. 相似文献
18.
Seasonal variation in home-range size and habitat area requirement of lesser spotted woodpeckers (Dendrocopos minor) were studied by radio-tracking in southern Sweden for 6 years. Home-range size did not vary between age-groups or sexes, but varied with season and decreased successively from 742 ha in winter (n=10), 355 ha in early spring (n=15), 103 ha in late spring (n=22) to 43 ha during nesting (n=10). The home-range in late spring (i.e. the 3–5 weeks preceeding egg-laying) represents the defended breeding territory. This included on average 39 ha of forest utilised for foraging (range 31–46 ha, n=15). Since food availability in late spring has a significant influence on reproductive success, and mortality is highest in this period, we regard this as an estimate of the habitat area requirement. This estimate is valid primarily for birds in southern Sweden, but circumstantial evidence indicate that the area requirement may not be grossly different in other areas with different forest types. For conservation of lesser spotted woodpeckers, management should focus on a minimum of 40 ha of forest dominated by deciduous trees, which may be fragmented over a maximum of 200 ha. 相似文献
19.
The potential as indicators of species richness were investigated for 178 species belonging to six ecologically defined species groups (epiphytic bryophytes on nutrient-rich bark, epiphytic macrolichens on nutrient rich bark, pendant lichens on conifer trees, bryophytes on siliceous rocks, bryophytes on dead conifer wood, and polypore fungi on dead conifer wood), using species data from 0.25 ha plots from three different coniferous forest areas (ca. 200 ha each). A species was defined as a potential indicator species for a species group within a study area if its distribution was statistically significantly nested within the species-plot matrix ranked according to species richness, and if the plot frequency of the species was less than 25%.Only two species were identified as potential indicators within all three areas and on average ≈80% of the potential indicator species were lost from one area to another. The results indicate that inconsistency between areas in the species’ frequency distributions and their position in nested hierarchies may strongly reduce the general predictive power of indicator species of species richness, even if significantly nested patterns are found at the community level. We suggest that indicators related to amount and quality of habitats may be an alternative to lists of indicator species of species richness. 相似文献