Factors affecting plant species richness in field boundaries in the Mediterranean region

Field boundaries are expected to support the maintenance of biodiversity in agroecosystems, since they provide the habitat for a range of plant species. However, plant diversity in field boundaries has decreased substantially in recent decades. This pattern is generally linked with the intensification of agricultural land use at field and landscape level. Therefore, we aimed to test the effect of farming management (field and boundary management), boundary structure (width and habitat assemblage considering the Mediterranean grassland element), and landscape heterogeneity on plant species richness of field boundaries. Plants were recorded along 30 field boundaries next to organic fields and 30 next to conventional fields located in 15 agrarian localities of NE Iberian Peninsula along a gradient of landscape complexity. A total of 517 plant species were identified in the 60 field boundaries. We recorded 162 species (31%) catalogued as rare, very rare or extremely rare in the flora of the Catalan Countries. Our results showed the importance of landscape heterogeneity, field management and habitat assemblage, since they were found to be the most influential variables for plant species richness; whereas boundary width and boundary management were seen to contribute less to explaining plant diversity. Accordingly, agri-environmental schemes should be designed to promote organic farming and maintain the structure of the landscape mosaic in order to benefit plant diversity in field boundaries in the Mediterranean region.     

Scale-dependent diversity effects of seed dispersal by a wild herbivore in fragmented grasslands

Dispersal limitation between habitat fragments is a known driver of landscape-scale biodiversity loss. In Europe, agricultural intensification during the twentieth century resulted in losses of both grassland habitat and traditional grassland seed dispersal vectors such as livestock. During the same period, populations of large wild herbivores have increased in the landscape. Usually studied in woodland ecosystems, these animals are found to disperse seeds from grasslands and other open habitats. We studied endozoochorous seed dispersal by roe deer (Capreolus capreolus) in fragmented grasslands and grassland remnants, comparing dispersed subcommunities of plant species to those in the established vegetation and the seed bank. A total of 652 seedlings of 67 species emerged from 219 samples of roe deer dung. This included many grassland species, and several local grassland specialists. Dispersal had potentially different effects on diversity at different spatial scales. Almost all sites received seeds of species not observed in the vegetation or seed bank at that site, suggesting that local diversity might not be dispersal limited. This pattern was less evident at the landscape scale, where fewer new species were introduced. Nonetheless, long-distance dispersal by large wild herbivores might still provide connectivity between fragmented habitats within a landscape in the areas in which they are active. Finally, as only a subset of the available species were found to disperse in space as well as time, the danger of future biodiversity loss might still exist in many isolated grassland habitats.     

Limited Effects of Large‐Scale Riparian Restoration on Seed Banks in Agriculture

I examined the effect of riparian forest restoration on plant abundance and diversity, including weed species, on agricultural lands along the Sacramento River in California (United States). Riparian forest restoration on the Sacramento River is occurring on a large‐scale, with a goal of restoring approximately 80,000 ha over 160 km of the river. In multiuse habitats, such as the Sacramento River, effects of adjoining habitat types and movement of species across these habitats can have important management implications in terms of landscape‐scale patterns of species distributions. Increased numbers of pest animals and weeds on agricultural lands associated with restored habitats could have negative economic impacts, and in turn affect support for restoration of natural areas. In order to determine the distribution and abundance of weeds associated with large‐scale restoration, I collected seed bank soil samples on orchards between 0 and 5.6 km from adjacent restored riparian, remnant riparian, and agricultural habitats. I determined the abundance, species richness, and dispersal mode of plant species in the seed bank and analyzed these variables in terms of adjacent habitat type and age of restored habitat. I found that agricultural weed species had higher densities at the edge of restored riparian habitat and that native plants had higher densities adjacent to remnant riparian habitat. Weed seed abundance increased significantly on walnut farms adjacent to restored habitat with time since restored. I supply strong empirical evidence that large areas of natural and restored habitats do not lead to a greater penetration of weed species into agricultural areas, but rather that weed penetration is both temporally and spatially limited.     

Can We Distinguish Plant Species that are Rare and Endangered from Other Plants Using Their Biological Traits?

Understanding the factors responsible for species rarity is crucial for effective species conservation. One possible approach to obtaining information about causes of species rarity is to compare rare and common species. We analyzed the biological and ecological traits of critically endangered (CR) plant species of the Czech Republic. We compared the vegetative, generative and ecological traits of CR species with: i) common closely related species (a form of phylogenetic correction), ii) common closely related species sharing the same habitat (i.e., excluding pairs not sharing the same habitat, because many differences in species traits can be caused by adaptation to a specific habitat type) and iii) all plants of the Czech Republic. Information about species traits was mainly obtained from literature and databases. Comparison with common closely related species showed that CR species are smaller, flower for shorter periods, and have higher proportions of self-compatibility and higher terminal velocities. CR species also differ in their mode of dispersion, and their ecology and distribution. Comparison with species from the same habitat gave similar results. Comparison with the whole flora produced slightly different results, with additional differences in pollination mode and seed mass. The results of all three types of comparison suggest that critically endangered species of the Czech Republic are small, competitively inferior species, with some differences in the generative part of their life cycle, and occur mainly in open, unproductive habitats.     

Forest edges and fire ants alter the seed shadow of an ant-dispersed plant

Exotic species invade fragmented, edge-rich habitats readily, yet the distinct impacts of habitat edges and invaders on native biota are rarely distinguished. Both appear detrimental to ant-dispersed plants such as bloodroot, Sanguinaria canadensis. Working in northeastern Georgia (USA), an area characterized by a rich ant-dispersed flora, fragmented forests, and invasions by the red imported fire ant, Solenopsis invicta , I monitored the interactions between ants and S. canadensis seeds in uninvaded forest interiors, uninvaded forest edges, invaded forest interiors, and invaded forest edges. I observed 95% of the seed dispersal events that occurred within the 60-min observation intervals. Seed collection rates were similar among all four (habitat × invasion) groups. The presence of invasive ants had a strong effect on seed dispersal distance: S. invicta collected most seeds in invaded sites, but was a poorer disperser than four of five native ant taxa. Habitat type (interior versus edge) had no effect on seed dispersal distance, but it had a strong effect on seed dispersal direction. Dispersal towards the edge was disproportionately rare in uninvaded forest edges, and ants in those habitats moved the average dispersed seed approximately 70 cm away from that edge. Dispersal direction was also skewed away from the edge in uninvaded forest interiors and invaded forest edges, albeit non-significantly. This biased dispersal may help explain the rarity of myrmecochorous plants in younger forests and edges, and their poor ability to disperse between fragments. This is the first demonstration that forest edges and S. invicta invasion influence seed dispersal destination and distance, respectively. These forces act independently.     

Disturbance,microclimate and historical habitat connectivity determine the population performance of the threatened grassland specialist Carex caryophyllea in remnant grasslands

Many grassland specialist plant populations in Europe have become restricted to remnant habitats. The performance of these populations depends on both species‐specific traits and local and landscape level aspects of habitat quality. Understanding which specific local or landscape level conditions determine the performance of grassland species populations in remnant habitats would help design the restoration of the habitats and to detect the conditions that favour the long‐term persistence of grassland species in them. Such information is especially needed in urbanised landscapes, where remnant habitats engulfed by urban land use types may experience increased erosion, higher temperatures and invasion by alien species. This study investigates the population performance determinants of Carex caryophyllea (VU), a grassland specialist, in 43 remnant grasslands in an urban‐rural gradient in Finland. The population performance was assessed with metrics of persistence, establishment and reproduction, and related to environmental conditions with generalized additive models and redundancy analysis. The most important positive determinants for the performance of C. caryophyllea populations were disturbance through management or ground erosion, a warm microclimate, large habitat area and high historical connectivity to suitable grassland habitats. Present connectivity to other C. caryophyllea populations had a weak and near‐significant positive relationship with population performance. Urbanisation of the surrounding landscape correlated with population performance as well, possibly due to the high historical cover of grasslands in presently urbanised landscapes. The results imply that the most effective restoration method of remnant C. caryophyllea populations would be reinstating disturbance regimes in overgrown habitats with warm microclimates close to suitable habitats and other existing populations, whether urban or rural. This would counteract the species future decline due to possible extinction debts and help the species persist in the study area in the long term.     

Patterns and correlates of plant diversity differ between common and rare species in a neotropical dry forest

Determining which factors affect species richness is important for conservation theory and practice. However, richness of common and rare species may be affected by different factors. We use an extensive inventory of woody plants from a tropical dry forest landscape in Yucatan, Mexico to assess the unique effects of environmental variables, spatial dependence of sampling sites, forest stand age and the combined effect of all groups of variables on species richness of woody plants with different levels of rarity (common, intermediate, rare, very rare)—according to their abundance, habitat specificity and spatial distribution range in the landscape. Analyzing separately common species and those with different levels of rarity uncovered contrasting patterns and correlates of species richness that were not apparent when focusing on all woody plants. In particular, richness of common and intermediate species was influenced mainly by environmental factors, whereas richness of very rare species was affected mostly by the unique effect of spatial dependence of sampling sites, suggesting a main role of environmental filtering and dispersal limitation, respectively. However, common and very rare species also responded inversely to some landscape metrics, revealing contrasting environmental preferences of these groups of species. These contrasting results suggest different underlying mechanisms and the need for very different conservation strategies. Therefore, basic and applied research on tropical forest biodiversity should consider separately species with different levels of rarity, focusing on which factors control variation in each level, and paying special attention to very rare species, generally the most specious and vulnerable to local extinction.     

Plant species occurrences in a rural hemiboreal landscape: effects of remnant habitats, site history, topography and soil

Changes in land use during the last century have caused fragmentation and a reduction in area of many species-rich habitats in the hemiboreal region. We examined abundances of plant species and their occurrence in different habitats in south-east Sweden. We found 361 plant species in 146 sample sites, which represented 14 different types of habitat. Most species were rare and occurred only in a few habitats. Almost half of all species (49%) were found in one or two habitats. Of these, 99 species occurred in one habitat only. The habitats with largest number of restricted species, i.e. habitat specialists, were dry to mesic semi-natural grasslands and remnant habitats such as road verges and mid field islets. The occurrence of 52 species was analysed with respect to topography, top- and subsoil and land use history. Few of the 52 species were affected by aspect or type of topsoil. Subsoil affected nearly half of the species and habitats with a convex landform influenced occurrence of > 90% of the species. Seventeen species were positively associated with a long continuity of grassland management, whereas two species were associated with lack of management. Open grasslands that are encroached by trees and shrubs show a decline in species number. Deciduous forests, especially wet deciduous forests, have a potential for restoring moist to mesic grassland habitats. Small remnant habitats are important for many of the species restricted to semi-natural grasslands. These habitats may function as "rescue sites" for the species, which in turn may promote dispersal and increase likelihood of restoration success. Therefore, remnant habitats are important for maintaining and restoring species richness in rural landscapes.     

Florally rich habitats reduce insect pollination and the reproductive success of isolated plants

Landscape heterogeneity in floral communities has the potential to modify pollinator behavior. Pollinator foraging varies with the diversity, abundance, and spatial configuration of floral resources. However, the implications of this variation for pollen transfer and ultimately the reproductive success of insect pollinated plants remains unclear, especially for species which are rare or isolated in the landscape. We used a landscape‐scale experiment, coupled with microsatellite genotyping, to explore how the floral richness of habitats affected pollinator behavior and pollination effectiveness. Small arrays of the partially self‐compatible plant Californian poppy (Eschscholzia californica) were introduced across a landscape gradient to simulate rare, spatially isolated populations. The effects on pollinator activity, outcrossing, and plant reproduction were measured. In florally rich habitats, we found reduced pollen movement between plants, leading to fewer long‐distance pollination events, lower plant outcrossing, and a higher incidence of pollen limitation. This pattern indicates a potential reduction in per capita pollinator visitation, as suggested by the lower activity densities and richness of pollinators observed within florally rich habitats. In addition, seed production reduced by a factor of 1.8 in plants within florally rich habitats and progeny germination reduced by a factor of 1.2. We show this to be a consequence of self‐fertilization within the partially self‐compatible plant, E. californica. These findings indicate that locally rare plants are at a competitive disadvantage within florally rich habitats because neighboring plant species disrupt conspecific mating by co‐opting pollinators. Ultimately, this Allee effect may play an important role in determining the long‐term persistence of rarer plants in the landscape, both in terms of seed production and viability. Community context therefore requires consideration when designing and implementing conservation management for plants which are comparatively rare in the landscape.     

Pollination and reproduction of a self-incompatible forest herb in hedgerow corridors and forest patches

Habitat-corridors are assumed to counteract the negative impacts of habitat loss and fragmentation, but their efficiency in doing so depends on the maintenance of ecological processes in corridor conditions. For plants dispersing in linear habitats, one of these critical processes is the maintenance of adequate pollen transfer to insure seed production within the corridor. This study focuses on a common, self-incompatible forest herb, Trillium grandiflorum, to assess plant–pollinator interactions and the influence of spatial processes on plant reproduction in hedgerow corridors compared to forests. First, using pollen supplementation experiments over 2 years, we quantified the extent of pollen limitation in both habitats, testing the prediction of greater limitation in small hedgerow populations than in forests. While pollen limitation of fruit and seed set was common, its magnitude did not differ between habitats. Variations among sites, however, suggested an influence of landscape context on pollination services. Second, we examined the effect of isolation on plant reproduction by monitoring fruit and seed production, as well as pollinator activity and assemblage, in small flower arrays transplanted in hedgerows at increasing distances from forest and from each other. We detected no difference in the proportion of flowers setting fruit or in pollinator activity with isolation, but we observed some differences in pollinator assemblages. Seed set, on the other hand, declined significantly with increasing isolation in the second year of the study, but not in the first year, suggesting altered pollen transfer with distance. Overall, plants in hedgerow corridors and forests benefited from similar pollination services. In this system, plant–pollinator interactions and reproduction seem to be influenced more by variations in resource distribution over years and landscapes than by local habitat conditions. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Trophic level modulates carabid beetle responses to habitat and landscape structure: a pan‐European study

1. Anthropogenic pressures have produced heterogeneous landscapes expected to influence diversity differently across trophic levels and spatial scales. 2. We tested how activity density and species richness of carabid trophic groups responded to local habitat and landscape structure (forest percentage cover and habitat richness) in 48 landscape parcels (1 km²) across eight European countries. 3. Local habitat affected activity density, but not species richness, of both trophic groups. Activity densities were greater in rotational cropping compared with other habitats; phytophage densities were also greater in grassland than forest habitats. 4. Controlling for country and habitat effects, we found general trophic group responses to landscape structure. Activity densities of phytophages were positively correlated, and zoophages uncorrelated, with increasing habitat richness. This differential functional group response to landscape structure was consistent across Europe, indicated by a lack of a country × habitat richness interaction. Species richness was unaffected by landscape structure. 5. Phytophage sensitivity to landscape structure may arise from relative dependency on seed from ruderal plants. This trophic adaptation, rare in Carabidae, leads to lower phytophage numbers, increasing vulnerability to demographic and stochastic processes that the greater abundance, species richness, and broader diet of the zoophage group may insure against.     

You don’t belong here: explaining the excess of rare species in terms of habitat,space and time

Ecological communities are composed of a few common and several rare species. Many studies have evaluated the shape of abundance distribution curves, but few studies have assessed the causes of rarity. Using a dataset of stream macroinvertebrates, we investigated whether the excess of rare species in three focal communities of stones in riffles were common 1) in other habitats at the same stream site and period of sampling (environment), 2) in other stream sites in the same habitat and period of sampling (space), and 3) in other years in the same stream site and habitat (time). We observed that around 28% of the rare species were common in other habitats (environment), stream sites (space) or years (time). Among the three factors, rarity was mostly explained by habitat type, whereas a significant portion of the rare species in riffles were common in pools, submerged roots of terrestrial plants or in partially submerged moss patches. This result suggests that the presence in non‐optimum habitat is a strong determinant of the rarity observed in natural communities and most rare species are due to sampling artifacts or accidentally sampled transient species.     

Steppe-like grassland as a refuge of the wild edible and medicinal plant species in anthropogenic landscape in northeastern Croatia

Habitat fragmentation and modification have been recognized as the most serious threats to biodiversity. In Croatia, the intensive human activities resulted in the landscape transformation, reduction of grassland areas and loss of species number. Increasingly threatened are the wild edible and medicinal plants which contribute remarkably to the biodiversity of different grassland types. In northeastern Croatia, one of the last remnants of the steppe-like grassland remained preserved in a very complex anthropogenic landscape. We examined the diversity of vascular plants occurring on this small habitat patch. Among the relatively high number of plant taxa (in a total of 177) found during the two years of investigations, most could be used both for human nutrition (28 taxa), and for the treatment of a wide range of diseases (60 taxa), while some taxa have nutritional value for livestock (17 taxa). All 23 recorded taxa with edible and medicinal properties are threatened in Croatia, 21 are threatened across Europe, and two are Red Listed taxa. Our results showed that small and isolated steppe-like grassland represents an important refuge for variety of valuable plant species in intensively used landscapes. Accordingly, such small habitats should be, at least locally, effectively protected.     

Habitat functionality for the ecosystem service of pest control: reproduction and feeding sites of pests and natural enemies

• 1 Landscape management for enhanced natural pest control requires knowledge of the ecological function of the habitats present in the landscape mosaic. However, little is known about which habitat types in agricultural landscapes function as reproduction habitats for arthropod pests and predators during different times of the year.
• 2 We studied the arthropod assemblage on six crops and on the seven most abundant native plant species in two landscapes over 1 year in Australia. Densities of immature and adult stages of pests and their predators were assessed using beat sheet sampling.
• 3 The native plants supported a significantly different arthropod assemblage than crops. Native plants had higher predator densities than crops over the course of the year, whereas crops supported higher pest densities than the native plants in two out of four seasonal sampling periods. Crops had higher densities of immature stages of pests than native plants in three of four seasonal sampling periods, implying that crops are more strongly associated with pest reproduction than native plants. Densities of immature predators, excluding spiders, were not different between native plants and crops. Spiders were, however, generally abundant and densities were higher on native plants than on crops but, because some species disperse when immature, there is less certainty in identifying their reproduction habitat.
• 4 Because the predator to pest ratio on native plant species showed little variation, and spatial variation in arthropod assemblages was limited, the predator support function of native vegetation may be a general phenomenon. Incentives that maintain and restore native remnant vegetation can increase the predator to pest ratio at the landscape scale, which could enhance pest suppression in crops.

     

Ditch network sustains functional connectivity and influences patterns of gene flow in an intensive agricultural landscape

In intensive agricultural landscapes, plant species previously relying on semi-natural habitats may persist as metapopulations within landscape linear elements. Maintenance of populations'' connectivity through pollen and seed dispersal is a key factor in species persistence in the face of substantial habitat loss. The goals of this study were to investigate the potential corridor role of ditches and to identify the landscape components that significantly impact patterns of gene flow among remnant populations. Using microsatellite loci, we explored the spatial genetic structure of two hydrochorous wetland plants exhibiting contrasting local abundance and different habitat requirements: the rare and regionally protected Oenanthe aquatica and the more commonly distributed Lycopus europaeus, in an 83 km² agricultural lowland located in northern France. Both species exhibited a significant spatial genetic structure, along with substantial levels of genetic differentiation, especially for L. europaeus, which also expressed high levels of inbreeding. Isolation-by-distance analysis revealed enhanced gene flow along ditches, indicating their key role in effective seed and pollen dispersal. Our data also suggested that the configuration of the ditch network and the landscape elements significantly affected population genetic structure, with (i) species-specific scale effects on the genetic neighborhood and (ii) detrimental impact of human ditch management on genetic diversity, especially for O. aquatica. Altogether, these findings highlighted the key role of ditches in the maintenance of plant biodiversity in intensive agricultural landscapes with few remnant wetland habitats.     

Habitat associations of epigeal spiders in upland calcareous grassland landscapes: the importance for conservation

Upland calcareous grassland landscapes are typically comprised of a matrix of calcareous grassland, acid grassland and limestone heath plant communities. This matrix of habitats is produced by a combination of underlying geology, climate and management. These landscapes are typically managed through grazing, with management targeted to maintain particular plant communities in the calcareous grassland habitat, whilst patches of acid grassland and limestone heath are not targeted by conservation management. The biodiversity value of acid grassland and limestone heath patches within the calcareous grassland matrix are unknown. This study provides the first assessment of their biodiversity value by examining aspects of epigeal spider diversity supported by these non-target habitat patches in comparison to calcareous grassland. Spiders were sampled in each habitat from April to August 2014 using pitfall traps across three upland regions in Great Britain. Spider species assemblages were distinct between limestone heath and both grassland types. Distinction in species assemblages are likely due to differences in vegetation structure and microclimate, e.g., humidity, degree of shade. Each habitat type supported several rare species (e.g., Jacksonella falconeri, Agyneta subtilis) revealing the contribution to spider fauna. The distinct spider species assemblage and presence of rare species in limestone heath patches demonstrate their importance in the upland calcareous grassland matrix. This study highlights the value of monitoring biodiversity in non-target habitats within a habitat matrix alongside those that are actively targeted by management.     

Distance to semi-natural grassland influences seed production of insect-pollinated herbs

Marginal grassland fragments, such as road verges and field margins, may act as important supplemental habitats for grassland plants in the modern agricultural landscape. However, abundance of pollinators in such fragments has been found to decline with distance to larger natural and semi-natural habitats, and this could have corresponding effects on plant pollination. In this study, we performed a field experiment on road verges with three insect-pollinated grassland herbs to examine the relationship between distance to semi-natural grassland and plant reproductive success in two landscapes with contrasting farming intensities. In Lychnis viscaria and Lotus corniculatus, seed production tended to decrease with increasing distance to semi-natural grassland, but only in the landscape with high farming intensity. Seed production in Armeria maritima spp. maritima decreased with distance in both landscapes. Although many studies have investigated effects of natural habitat on crop pollination, little is known about the impact on pollination in native plants. The results from this study indicate that management of semi-natural grasslands improves not only biodiversity within the actual grassland but also pollination of native plants in the surrounding agricultural landscape.     

Better common than rare? Effects of low reproductive success,scarce pollinator visits and interspecific gene flow in threatened and common species of Tibouchina (Melastomataceae)

The reasons for plant rarity have been the focus of many studies, especially because rare species are more prone to extinction than common species. Under the same habitat conditions, rare plants are expected to attract fewer flower visitors and to show some limitation in their reproductive success. Here, using one of the most emblematic Neotropical plant genus (Tibouchina) we tested whether narrow endemic and threatened species in Ecuador have a lower reproductive success or are visited by fewer pollinators than common species, in 13 populations monitored from 2011 to 2013. We also assessed whether interspecific gene flow could be considered a threat to the rare species. However, contrary to expectations, we found that few pollinators visited the flowers, independently of species rarity. Natural outcross pollinations were always very low in all small‐size populations, leading to high levels of pollen limitation. Interspecific crossing experiments also revealed weak reproductive barriers in some species. This study reveals that both narrow and common species of Tibouchina have similar reproductive and pollinator patterns in Ecuador and, therefore, other causes of the rarity of these species should be considered.     

Determinants of species rarity: population growth rates of species sharing the same habitat

Determining differences between common and rare species is commonly used to identify factors responsible for rarity. Existing studies, however, suffer from two important drawbacks. First, studies compare species that are closely related phylogenetically but occupy different habitats. Second, these studies concentrate on single life history traits, with unknown relevance for population growth rates. Complete life cycles of one rare and one common Cirsium species sharing the same habitat were compared. Population growth rate was slightly lower in the rare species, translating into a large difference in local extinction probability. Seed predation intensity did not differ between species. However, it can be demonstrated that in connection with the data on complete demography, seed predation is the key factor causing a lower population growth rate in the rare species. These results are the first estimation of factors responsible for commonness or rarity of plants in terms of population growth rate without confounding differences in ecology. They demonstrate that conclusions based on single traits may be misleading and that only a comparison based on a complete life cycle can provide unequivocal evidence for concluding which factors are really those responsible for species commonness or rarity.     

桂林漓江沿岸植物区系特点及其与景观的关系

桂林漓江沿岸原生植被受破坏严重 ,植物区系为次生性质 ,其特点 :( 1 )种类丰富 ,共有野生维管束植物 80 8种 ,隶属于 1 5 6科、483属 ;( 2 )植物区系的地理成份复杂 ,可将 45 4个种子植物属归为 1 4个类型 ,以热带、亚热带类型为主 ,温带类型次之 ,中国特有属 6个 ;( 3 )植物区系岩溶特性明显 ,属于东亚植物区、中国—日本森林植物亚区、岭南山地地区的一个小区。植物景观是桂林漓江沿岸风景的重要组成部分 ,具体表现在各类植物群落的外貌和一些重要植物种类的花、果和叶色的季节性变化上。现存的主要植物群落以次生藤刺灌丛为主 ;少见尚存的喀斯特常绿、落叶阔叶混交林 ;独有的喀斯特硬叶常绿阔叶林 :以乌冈栎为建群种的山顶矮林 ,是我国东部湿润亚热带地区罕见的残遗植被类型 ,在构成景观和科研上均有特殊意义。沿河岸分布的植物是最吸引游人注意的重要景观 ,形状各异的灌丛、杂木林、竹林和农田植被等都是风景的重要组成部分