Removing an exotic shrub from riparian forests increases butterfly abundance and diversity

Invasive plants are one of the greatest threats to endangered insect species and a major threat to Lepidoptera in eastern North America. We investigated the effects of the invasive shrub Chinese privet (Ligustrum sinense) and two methods (mulching or hand-felling) of removing it from riparian forests on butterfly communities and compared them to untreated, heavily invaded control plots and to “desired future condition” forests that never had extensive privet cover. Privet mulching resulted in nearly twice as many butterflies as privet felling and both treatments had more butterflies two years after privet removal than untreated control plots. Butterfly communities on control plots differed from those on the two treatments and the desired future condition forests. A number of forest characteristics were evaluated but only herbaceous plant cover (excluding privet) was positively correlated with butterfly abundance, diversity and evenness. The Carolina satyr, Hermeuptychia sosybius, was the best indicator of forests where privet had never invaded. Removing Chinese privet from riparian forests in the southeastern United States greatly improved forest habitats for butterflies and evidence suggests that butterfly communities in other temperate forests could benefit from removal of extensive shrub layers dominated by a single species.     

Influence of forest riparian vegetation on abundance and biomass of nocturnal flying insects

Despite widespread recognition of linkages between vegetation and insects, understanding of the ecological mechanisms underlying these relationships is limited. Better comprehension of relationships linking abundance and biomass of insects to vegetation would increase accuracy of predictions of the effects of forest management activities on insect communities. This knowledge could also be pivotal to understanding predator–prey dynamics linked to insect populations. We sampled nocturnal flying insects and measured vegetation characteristics in 34 stream reaches in conifer-dominated forests of the Oregon Coast Range in the Pacific Northwest of the United States. We considered five a priori hypotheses (resource quality, resource diversity, resource abundance, resource concentration, and stream cover hypotheses) that could explain mechanisms underlying associations between riparian vegetation and nocturnal flying insects, and used an information-theoretic approach to determine the relative strength of evidence for each. The resource quality hypothesis, which predicts that abundance and biomass of insects increases with cover of deciduous vegetation, explained substantial variation for nearly every order of insect investigated, whereas the remaining hypotheses explained relatively little. Abundance and biomass of insects had stronger associations with characteristics of canopy trees than with characteristics of shrub or understory trees, suggesting that deciduous trees are an important habitat element for nocturnal flying insects in these areas. Resource managers planning riparian vegetation management in conifer-dominated forests should be aware that manipulation of the cover of deciduous trees in riparian areas could have a large impact on these insects and their vertebrate predators. By providing information on forest canopy composition, remote sensing may offer a low-cost tool for identifying areas with high abundance and biomass of insects during conservation planning.     

The role of herbicide in savanna restoration: Effects of shrub reduction treatments on the understory and overstory of a longleaf pine flatwoods

Woody plant encroachment is a threat to savanna ecosystems worldwide. By exploiting differences in the physiology and seasonality of herbaceous species and encroaching hardwoods, herbicides can be used to control woody shrubs in savannas without causing lasting harm to desirable vegetation. We applied three herbicides and one tank mix to control shrubs following removal of the slash pine (Pinus elliottii Engelm.) canopy and replanting with container-grown longleaf pine (Pinus palustris Mill.) seedlings in a mesic-wet savanna in the southeastern USA. The herbicides tested were imazapyr, sulfometuron methyl, hexazinone, and a hexazinone + sulfometuron methyl tank mix. 4 years after application, no negative effects on understory species richness, diversity, evenness, or community composition were evident in any of the herbicide treatments. Oaks (Quercus spp.), one of the dominant shrub genera on the study site, were resistant to sulfometuron methyl, and this herbicide was therefore ineffective both as a pine release treatment and for enhancing herbaceous species cover. Imazapyr was the most effective treatment overall, leading to significant improvements in longleaf pine seedling growth and also enhancing herbaceous species cover. Both hexazinone and the hexazinone + sulfometuron methyl tank mix provided some seedling growth and understory enhancement as well. In particular, the tank mix significantly increased wiregrass cover relative to the control. Shrubs resprouted quickly following a dormant-season prescribed fire in the fifth year after treatment, indicating that herbicide-related increases in herbaceous cover may be lost if an aggressive prescribed fire program is not implemented.     

A baseline classification of riparian woodland plant communities in the Okavango Delta,Botswana

In the Okavango Delta information on the riparian woodland vegetation community composition and distribution is generally lacking. Past studies in the Delta were mainly focused on the quantitative classification of seasonal floodplain herbaceous vegetation communities. The aim of this study was to determine riparian woodland vegetation communities in the Okavango Delta. Vegetation sampling was conducted in 20?m × 50?m randomly placed plots. The plots were placed along a gradient from the main water body to the drier fringe of the riparian zone. Plant species present in each plot were recorded with their estimated percentage cover using the Braun–Blanquet cover abundance scale. Hierarchical cluster analysis was used to determine vegetation communities. Indicator species analysis was used to calculate indicator values for species groups defined from the cluster analysis. Plant species and diversity were determined for each vegetation cluster. Multi-response permutation procedures (MRPP) were used to determine significance of differences between communities. The Kruskal–Wallis test was used to compare species diversity and richness between vegetation communities. Four vegetation communities were identified: Croton megalobotrys– Hyphaene petersiana, Vachellia erioloba–Diospyros lycioides, Syzygium cordatum–Phoenix reclinata and Garcinia livingstonei–Senegalia nigrescens. In this classification, the Syzygium cordatum–Phoenix reclinata and Garcinia livingstonei–Senegalia nigrescens plant communities are found in frequently flooded regions, whereas the Croton megalobotrys–Hyphaene petersiana and Vachellia erioloba–Diospyros lycioides are in occasionally flooded regions. Total number of species was highest in the Garcinia livingstonei–Senegalia nigrescens and lowest in the Syzygium cordatum–Phoenix reclinata vegetation communities. The MRPP showed that there was significant (p < 0.05) differences between vegetation communities. Species diversity and richness were significantly (p < 0.05) higher in the Garcinia livingstonei–Senegalia nigrescens vegetation community. This study provided an inventory of riparian woodland plant communities, which can be used as a vital monitoring tool of vegetation change in the Okavango Delta.     

黄山率水流域水陆交错带植被类型及群落特征

研究以黄山市率水流域水陆交错带典型植物群落为对象,沿主河道设置了 33 个样方,采用 法瑞学派调查法记录样方的物种组成和群落结构;并根据离水面距离和土壤基质类型划分了 3 种生境类 型：砾石型河漫滩、粘土型河漫滩以及河岸边坡,进而进行群落类型划分与生态梯度分析。结果表明： 调查区域有维管束植物共计 67 科 124 属 146 种;水陆交错带植被可分成 15 个群落类型,包含 3 个森林 群落、3 个灌丛群落和 9 个草本群落;森林群落均出现在河岸边坡生境类型中,灌从群落多见于粘土型河 漫滩,草本群落主要集中于砾石型河漫滩;非度量多维标度分析表明,存在于上下游之间和水陆之间的 两个生态梯度是影响群落物种组成的重要因素,并且在两个生态梯度中心过渡区,植物群落丰富度达到 最大。     

A comparison of impacts from silviculture practices and North American beaver invasion on stream benthic macroinvertebrate community structure and function in Nothofagus forests of Tierra del Fuego

The sub-Antarctic biome of South America is the world's southernmost forested ecosystem and one of the last remaining wilderness areas on the planet. Nonetheless, the region confronts various anthropogenic environmental impacts, such as the invasive North American beaver (Castor canadensis) and timber harvesting, particularly in stands of Nothofagus pumilio. Both of these disturbances can affect terrestrial and aquatic systems. To understand the influence and relative importance of these disturbances on sub-Antarctic watersheds, we characterized in-stream and riparian habitat conditions (pH, dissolved oxygen, conductivity, temperature, stream size, distance to riparian forest, bank slope, substrate heterogeneity, benthic organic matter) and benthic macroinvertebrate community structure (density, richness, diversity, evenness) and function (biomass, functional feeding group percent) in 19 streams on Tierra del Fuego Island. To explain the effects of beaver invasion and timber harvesting, we compared these physical and biotic variables among four habitat types: (a) beaver meadows, (b) shelterwood cut harvested areas without forested riparian zones, (c) variable retention harvested areas with riparian buffers, and (d) unmanaged old-growth primary forests. Most habitat variables were similar at all sites, except for dissolved oxygen (significantly higher in streams from old-growth primary forests). Benthic communities in beaver meadows had significantly lower diversity, compared to streams of unmanaged old-growth primary forests, and managed sites presented intermediate values between the two. Functionally, the benthic community in beaver meadows displayed a reduction of all functional feeding groups except collector-gatherers; again variable retention harvested areas with riparian buffers were similar to unmanaged old-growth primary forest streams, while shelterwood cut harvested areas occupied an intermediate position. These results indicated that current forestry practices that include both variable retention and legally mandated riparian forested buffers may be effective in mitigating impacts on stream benthic communities. Finally, these data demonstrated that C. canadensis invasion was a relatively larger impact on these streams than well-managed forestry practices.     

Trophic consequences of postfire logging in a wolf–ungulate system

Controversy surrounds postfire logging, often because of negative effects on snag-dependent wildlife species. Few studies, however, have examined effects on early-seral species that may benefit from postfire logging, nor effects on trophic relationships. We studied the effects of postfire logging on trophic dynamics between wolves (Canis lupus), three ungulate species and ungulate forage biomass during the first 3 years in a large burn in the Canadian Rockies, Alberta, Canada. We examined plant biomass and ungulate responses to two treatments (post- and prefire logging) compared to a burned but unlogged area (control). We evaluated resource selection for the three treatments by elk (Cervus elaphus) using radiotelemetry and for deer (Odocoileus spp.), moose (Alces alces), and, secondarily, elk using pellet counts. Elk resource selection was modeled as a function of the trade-off between wolf predation risk and herbaceous forage biomass to test for trophic impacts of postfire treatments. Postfire logging had transient effects on total herbaceous biomass; while forb biomass was reduced, increases in graminoid biomass more than compensated by the third year. Prefire logging areas were dominated by a few species, but had generally higher forage biomass by the third year. Ungulates avoided postfire and prefire logged areas despite greater herbaceous biomass. Only when we considered elk resource selection as a function of both forage and wolf predation risk was the extent to which trophic interactions affected by postfire logging revealed. Wolves selected proximity to roads and the higher forage biomass associated with postfire logging in open logged areas. This translated to the highest predation risk for elk in postfire logged areas. Thus, ungulates avoided postfire logged areas because of human alteration of top-down predation risk despite enhancements to bottom-up forage biomass. Managers should consider trophic consequences of postfire logging on the interactions among species when gauging logging effects on terrestrial ecosystems. Making use of existing roads, minimizing the construction of new roads, and managing road removal following postfire logging will help mitigate the negative effects of postfire logging on terrestrial ecosystems.     

Plant community responses to a gradient of site preparation intensities in pine plantations in the Coastal Plain of North Carolina

Intensively managed loblolly pine (Pinus taeda) forests are common in the southeastern United States and offer opportunities for conservation of biologic diversity. Within intensively managed landscapes, stand establishment relies on combinations of mechanical and chemical site preparation and herbaceous weed control (HWC) to manage competing vegetation and increase pine production. However, few long-term studies have described relationships between intensity of stand establishment and effects on plant communities. Therefore, we examined effects of 6 treatments that varied in intensity via combinations of mechanical (wide spacing and strip shear or narrow spacing and roller chop) and chemical (application or no application) site preparation treatments with HWC (broadcast or banded) from 1 to 8 years after site preparation on plant communities in loblolly pine plantations (n = 6) in the Coastal Plain of North Carolina, USA. All treatments resulted in abundant and diverse plant communities. Chemical site preparation had short lived (?4 year) effects on the herbaceous community but long-term effects on woody plants and pine cover. Increasing management intensity by including broadcast HWC or roller chop/narrow spacing did not additively reduce woody vegetation cover or species richness. However, broadcast HWC reduced grass, vine, and forb cover in the first year post-treatment. Average Morista community similarity values ranged from 0.69 to 0.89 among treatments and plots receiving the same chemical site preparation contained the most similar plant communities. Banded HWC can be paired with wide spacing to maximize herbaceous plant growth important for many wildlife species, particularly in the first few years after site preparation. Site preparation techniques should be tailored to local site conditions, plant communities, and management objectives.     

A century of riparian forest expansion following extreme disturbance: Spatio-temporal change in Populus/Salix/Tamarix forests along the Upper San Pedro River,Arizona, USA

Populus–Salix forests are a valued riparian vegetation type in western North America. These pioneer, obligate phreatophytes have declined on some rivers, raising conservation concerns and stimulating restoration plantings, but have increased on others. Understanding patterns and causes of forest change is essential for formulating conservation, restoration and management plans. Our goal was to assess spatio-temporal patterns of vegetation change on the Upper San Pedro River in semiarid Arizona, USA, one of the few undammed rivers in the region. Over 100 years ago, intense floods initiated channel incision and substantially altered hydrogeomorphology. Pioneer trees began to establish in the widening post-entrenchment zone as the surfaces began to stabilize. Using a time-series of aerial photographs (1955–2003) we quantified recent change in area of riparian cover types. Analysis indicated that wooded area in the post-entrenchment zone nearly tripled from 1955 to 2003, at the expense of bare ground, and the active channel narrowed appreciably. This forest expansion represents a long-term response to river entrenchment, with the temporal pattern influenced by recent flood cycles and biogeomorphic feedbacks. Populus–Salix have established episodically during the infrequent years with high winter flood runoff, sequentially filling available recruitment space. Older cohorts cover wide swaths of the floodplain while young trees form narrow bands lining the channel. Barring extreme flooding, the pioneer forests are expected to senesce over the coming century. An additional factor that has shaped the pattern of post-entrenchment forest expansion is anthropogenic water withdrawal. Populus–Salix forest increase has been greatest within a conservation area, where stream flows are largely perennial. In drier, agricultural sectors, Populus–Salix have declined while the more deeply-rooted Tamarix has increased. Overall, the study reveals that long-term fluctuations in pioneer forest area and age structure are common on dryland rivers, and shows how past events such as extreme floods can interact with recent environmental practices such as freshwater withdrawal to influence riparian forest patterns. This underscores the necessity of a long-term perspective for forest conservation and management.     

Time to rethink the management intensity in a Mediterranean oak woodland: the response of insectivorous birds and leaf-chewing defoliators as key groups in the forest ecosystem

? Context

The Iberian cork oak Quercus suber montados are dynamic agro-silvo-pastoral systems, contrasting with the abandonment trend of other Mediterranean forested areas.

? Aims

We aimed to identify the effect of management type and vegetation features on breeding insectivorous birds and leaf-chewing defoliator insects.

? Methods

In central Portugal, we selected two groups of 20 sites: dense montados (DM, high cover of cork oaks and low cattle impact) and sparse montados (SM, low cover of oaks and high cattle impact). We collected variables associated with vegetation features, bird community and chewing defoliators.

? Results

The two systems differed significantly in oak trunk diameter, oak and shrub cover, tree and shrub diversity. Ground bird densities were higher in SM with fragmented shrub cover. In DM, higher woody vegetation cover and diversity can promote shrub birds and leaf warblers. Oak defoliation was mainly attributed to the sawfly Periclista andrei. Sawfly defoliation was significantly higher in SM and negatively correlated with shrub cover.

? Conclusions

Our results highlight (1) the relevance of management activities conducted at the shrubby layer, (2) the need of an increase in tree diversity and density and (3) the maintenance of a mosaic landscape in order to improve the bird community richness and reduce the defoliation impact in montado system.     

Plant-soil biodiversity relationships and nutrient retention in agricultural riparian zones of the Sacramento Valley,California

Forested riparian buffers in California historically supported high levels of biodiversity, but human activities have degraded these ecosystems over much of their former range. This study examined plant communities, belowground biodiversity and indicators of multiple ecosystem functions of riparian areas across an agricultural landscape in the Sacramento Valley of California, USA. Plant, nematode and soil microbial communities and soil physical and chemical properties were studied along 50-m transects at 20 sites that represented the different land use, soil and vegetation types in the landscape. Riparian zones supported greater plant diversity and nearly twice as much total carbon (C) per hectare compared to adjacent land managed for agricultural uses, but had generally lower soil microbial and nematode diversity and abundance. When woody plant communities were present in the riparian zone, plant diversity and species richness were higher, and soil nitrate and plant-available phosphorus levels were lower. Belowground diversity and community structure, however, appeared to depend more on plant productivity (as inferred by vegetation cover) than plant diversity or species richness. Greater plant species richness, nematode food web structure, total microbial biomass, woody C storage and lower soil nitrate and phosphorus loading were correlated with higher visual riparian health assessment scores, offering the possibility of managing these riparian habitats to provide multiple ecosystem functions.     

Response of vegetation, shade and stream temperature to debris torrents in two western Oregon watersheds

This study examines watershed patterns of riparian vegetation, shade, and stream temperature eight years after extreme storm events triggered numerous debris torrents throughout the Pacific Northwest. We examined twelve impacted streams in two western Oregon watersheds: the Calapooia River in the western Cascades and the Williams River in the Coast Range. Red alder (Alnus rubra) and willow (Salix spp.) were the dominant species on debris torrented areas in both watersheds. Post-disturbance vegetation recovery was significant in both watersheds, impacting shade and stream temperatures. However, red alder density, basal area, and height were significantly greater along streams in the Williams River watershed than along streams in the Calapooia River watershed. Willow density, basal area and height were similar between the watersheds. Stream shading levels mirrored red alder growth, with greater average shading in the Williams River watershed. The greater shade translated into lower summer maximum stream temperatures and maximum diurnal stream temperature fluctuations in the Williams River as compared to the Calapooia River watershed. Minimum stream temperatures were not different between the two watersheds. The rapid re-growth of red alder along the Williams River watershed ultimately lead to a rapid decline in maximum summer stream temperatures for that watershed compared to the Calapooia River watershed. The location where the disturbance occurred had an important role in determining the rate and pathway of stream recovery.     

Influence of wildfire severity on riparian plant community heterogeneity in an Idaho,USA wilderness

Despite the increasing recognition of riparian zones as important ecotones that link terrestrial and aquatic ecosystems and of fire as a critical natural disturbance, much remains unknown regarding the influence of fire on stream-riparian ecosystems. To further this understanding, we evaluated the effects of mixed severity wildfire on riparian plant community structure and composition in headwater streams of the Big Creek Watershed of the Frank Church ‘River of No Return’ Wilderness of central Idaho. Five years after a large stand-replacing fire, we conducted riparian vegetation surveys at sixteen reaches across a range of burn types. Non-metric Multidimensional Scaling (NMS) and Multi-Response Permutation Procedure (MRPP) analyses showed an overall shift in community composition and structure between vegetation at unburned and severely burned reaches. Although total plant cover was significantly less at severely burned areas, recovery of the deciduous understory was apparent. Severely burned reaches were characterized by a marked increase in cheatgrass (Bromus tectorum). Reaches that were exposed to low-severity fire were indistinguishable from unburned reaches relative to vegetation community composition and structure, pointing to a possible disturbance threshold that may need to be crossed in order to alter riparian plant communities.     

Vegetation structure,composition and effect of pine plantation harvesting on riparian buffers in New Zealand

The composition and structure of vegetation within riparian buffers prior to, and immediately post-harvesting in a managed radiata pine (Pinus radiata D.Don) forest is described and compared with riparian buffers in residual adjoining native forest on the Coromandel Peninsula, New Zealand. One hundred and twenty-one species (71% native) representing life forms from grasses to trees were recorded. The highest species richness, including both native and adventive (non-native) species, was found in riparian buffers in the post-harvest and native reference sites which had 18–25 species per site. Riparian buffers in mature pine plantations contained a mix of native species that was generally similar to, and not significantly reduced in species richness, from the reference native forest. Native species comprised 82–92% of the total cover in mature pre-harvest sites (irrespective of riparian width), and 99.8% in native reference sites. Compared with native forest the principal difference was a reduction of total cover in the upper tiers (5–12 m), and some increase in cover in the lower tiers. Adventive species in post-harvest sites comprised 16–67% of the total cover and were most frequently found in riparian areas highly disturbed by recent harvesting of the pines, particularly where riparian buffers were narrow or absent. Invasion by light-demanding adventives is expected to be temporary and most species are likely to be shaded out as the new rotation of pine trees develops. Radiata pine plantations in Whangapoua Forest can provide suitable conditions for the development of riparian buffer zones that will become dominated by native species, similar in richness and structure to neighbouring native forest.     

Landscape hierarchies influence riparian ground-flora communities in Wisconsin, USA

We examined the distribution of ground-flora species (herbaceous and woody species <1 m tall) across riparian areas of northeastern Wisconsin in an effort to understand how hierarchical landscape properties, such as the physiographic system (ground moraine and outwash plain), valley system (constrained and unconstrained), and valley floor landforms influence distribution patterns of ground-flora species and functional plant guilds across riparian areas of small streams and rivers in a glacial landscape. A total of 162 species were recorded on 417 (1 m²) plots stratified by four different valley types that reflect the dominant physiographic system and valley system (constrained ground moraine, constrained outwash plain, unconstrained ground moraine, unconstrained outwash plain) and transverse geomorphic structure (valley floor landforms including floodplains, terraces, slopes, and adjacent uplands). Although distribution patterns of individual ground-flora species are highly variable among the four valley types, canonical correspondence analyses (CCA) of individual valley types indicate that ground-flora vegetation is related strongly to hierarchical landscape properties, including valley type and the transverse geomorphic structure of the stream valley. Vegetation ultimately reflects the influence of hydrogeomorphic processes that shape valley floor landforms. Constrained valley types tend to be characterized by diverse floodplain ground-flora communities dominated by graminoids and pteridophytes, while the terraces and slope plant communities are comprised of facultative upland and obligate upland perennial forb and woody species whose distribution appears to be a function of topographic features, such as aspect. However, ground-flora communities of unconstrained valley types appear to be responding not only to changes associated with the transverse geomorphic structure of the riparian ecotone, but also to more localized changes in environmental conditions associated with flooding and hydrologic regime. As a result, floodplain, terrace, and slope ground-flora communities tend to be diverse, dominated by a mixture of obligate wetland, facultative wetland, and facultative species. Thus, variation in riparian plant community characteristics can be explained using a nested, hierarchical landscape framework to organize and group different riparian settings based on the underlying geomorphic processes shaping stream valleys. Based on these results, we suggest that riparian management zones (RMZs) designed to maintain riparian function should be variable in width rather than fixed, encompassing variation in valley floor landforms and valley walls, regardless of the physiographic system.     

Invasion and management of a woody plant, Lantana camara L., alters vegetation diversity within wet sclerophyll forest in southeastern Australia

Plant invasions of natural communities are commonly associated with reduced species diversity and altered ecosystem structure and function. This study investigated the effects of invasion and management of the woody shrub Lantana camara (lantana) in wet sclerophyll forest on the south-east coast of Australia. The effects of L. camara invasion and management on resident vegetation diversity and recruitment were determined as well as if invader management initiated community recovery. Vascular plant species richness, abundance and composition were surveyed and compared across L. camara invaded, non-invaded and managed sites following L. camara removal during a previous control event by land managers. Native tree juvenile and adult densities were compared between sites to investigate the potential effects of L. camara on species recruitment. Invasion of L. camara led to a reduction in species richness and compositions that diverged from non-invaded vegetation. Species richness was lower for fern, herb, tree and vine species, highlighting the pervasive threat of L. camara. For many common tree species, juvenile densities were lower within invaded sites than non-invaded sites, yet adult densities were similar across all invasion categories. This indicates that reduced species diversity is driven in part by recruitment limitation mechanisms, which may include allelopathy and resource competition, rather than displacement of adult vegetation. Management of L. camara initiated community recovery by increasing species richness, abundance and recruitment. While community composition following L. camara management diverged from non-invaded vegetation, vigorous tree and shrub recruitment signals that long-term community reinstatement will occur. However, secondary weed invasion occurred following L. camara control. Follow-up weed control may be necessary to prevent secondary plant invasion following invader management and facilitate long-term community recovery.     

Assessment of small mammal diversity in coffee agroforestry in the Western Ghats,India

Coffee agroforestry is a conservation strategy that has shown promise to support the diversity of bird, bat, and insect communities, but few studies have focused on non-volant mammals in coffee farms. We assessed mammal diversity within coffee agroforestry systems in Kodagu, India and investigated the impacts of the non-native shade tree species, Grevillea robusta, on mammal diversity. Twenty farms, with varying amounts of G. robusta planted within the coffee farm, were sampled throughout three rainfall zones during the 4-month study period. We captured six species of small mammals, with indirect methods yielding an additional five species, totaling 11 mammal species. Contrary to current ecological thought, we found that increased amounts of G. robusta did not have a negative impact on either abundance or richness of mammals. Small mammal abundances were higher at farms with greater amounts of herbaceous ground cover and larger, mature shade trees, while small mammal species richness was found to increase with an increase in tree species richness as well as greater amounts of herbaceous ground cover. Additionally, small mammal abundance was higher at coffee farms closer to forested areas. Based on these findings, we suggest the maintenance or cultivation of shade tree richness, mature shade trees, and herbaceous ground cover within coffee farms and preservation of forested areas within the landscape to enhance coffee agroforestry habitat for non-volant mammals. We hope that these habitat requirements will be incorporated into conservation strategies for the promotion of biodiversity within coffee agroforestry systems.     

Short- and long-term impacts of an introduced large herbivore (Buffalo, Bubalus bubalis L.) on a neotropical seasonal forest

Herbivory of large mammals is a key factor influencing plant communities, with effects on plant growth, survival and reproduction. These effects may be more pronounced when the herbivores are exotic ungulates. We evaluated the impacts of buffaloes (density of 1 individual per hectare) on sapling and shrub assemblages in a semideciduous seasonal forest in southern Brazil. We also investigated whether these impacts could affect the long-term maintenance of forest communities. To address these points, we used two distinct approaches in fragments of seasonal forests located in buffalo farms: firstly, by establishing a buffalo-exclusion experiment (over 14?months), and secondly, by comparing areas with three different histories of buffalo occurrence (protected from buffalo encroachment for 3 and 10?years and freely accessed by buffalo). In both approaches, we evaluated the following ecological attributes: plant cover, richness, diversity (Shannon index), biomass and average height. The results of the exclusion experiment did not indicate any significant effect of buffalo exclusion for the evaluated ecological attributes. On the other hand, species composition differed between communities when comparing buffalo presence versus 10?years of buffalo exclusion. Moreover, richness increased and average height decreased after this 10-year period. We also detected an increase in diversity and a retraction of soil compaction, after 10?years of exclusion. We conclude that forest patches do not show short-term responses to buffalo removal. Nevertheless, in the long-term absence of large herbivores, the forest tends to develop in complexity by increasing in species richness.     

Bird species diversity in riparian buffers,row crop fields,and grazed pastures within agriculturally dominated watersheds

In response to concern about the loss of ecosystem services once provided by natural riparian systems, state and federal agencies have established incentive programs for landowners to convert sensitive lands from agricultural to conservation uses. Enhancement of wildlife habitat, while identified as a function of such systems, has often been of secondary importance to soil conservation and water quality objectives. Though greatly important, little consideration has been given to how specific species will respond to the design and management of riparian buffers or other conservation lands. This study compared avian communities within a chronosequence of riparian buffers established on previously cropped or pastured land with those of the nearby matrix land cover types (row crop fields and an intensively grazed pasture). The riparian buffers consisted of native grasses, forbs, and woody vegetation established at three different times (2, 9, and 14+ years prior to survey). At each site, 10 min point counts for breeding birds were conducted using 50 m fixed radius plots, which were visited eight times between May 15 and July 10, 2008. A total of 54 bird species were observed over all of the study sites. The re-established riparian buffers in this study had higher bird abundance, richness, and diversity than the crop and pasture sites. These results suggest that re-establishing native riparian vegetation in areas of intensive agriculture will provide habitat for a broad suite of bird species, but that specific species will reflect successional stage, horizontal and vertical vegetative structure, and compositional diversity of the buffer vegetation. These results emphasize the importance of matching buffer design and management to species requirements if the objectives are to attract specific target species or species groups.