effects of extensive grazing on the vegetation of a landscape-scale restoration site

The Wicken Fen Vision (Cambridgeshire, UK) is a landscape-scale habitat restoration project that uses process-driven, open-ended approaches to develop habitats on highly degraded and drained peat soils of former intensive arable land. The project land is extensively grazed with herds of free-roaming, minimally managed herds of Highland cattle and Konik horses. In one 119 ha area, seven 25m x 25 m grazing exclosures were erected and vascular plant species were recorded from 2007 to 2017. Plant species data were analysed to (1) compare changes in plant species composition and diversity in grazed and ungrazed areas; (2) use plant species traits and plant-environment associations to explore the nature of changes in plant composition; (3) use remote sensing to explore changes in vegetation structure; (4) examine the influence of land use histories on grazing outcomes in different parts of the site.There was a clear divergence through time between grazed and ungrazed areas, attributed to significantly greater canopy height, Ellenberg L (Light) and Ellenberg N (fertility) values within the exclosures. Species richness was significantly higher in grazed compared with ungrazed areas and species assemblages separated through the study period. After ten years, extensive free-roaming grazing has had significant impacts on vegetation structure and species richness but effects varied across the study site because of differing historical land use.

How Biodiversity-Friendly Is Regenerative Grazing?

Regenerative grazing management (ReGM) seeks to mimic natural grazing dynamics to restore degraded soils and the ecological processes underpinning sustainable livestock production while enhancing biodiversity. Regenerative grazing, including holistic planned grazing and related methods, is an adaptive, rotational stocking approach in which dense livestock herds are rotated rapidly through multiple paddocks in short bouts of grazing to defoliate plants evenly and infrequently, interspersed with long recovery periods to boost regrowth. The concentrated “hoof action” of herds in ReGM is regarded vital for regenerating soils and ecosystem services. Evidence (from 58 studies) that ReGM benefits biodiversity is reviewed. Soils enriched by ReGM have increased microbial bioactivity, higher fungal:bacteria biomass, greater functional diversity, and richer microarthropods and macrofauna communities. Vegetation responds inconsistently, with increased, neutral, or decreased total plant diversity, richness of forage grasses and invasive species under ReGM: grasses tend to be favored but shrubs and forbs can be depleted by the mechanical action of hooves. Trampling also reduces numerous arthropods by altering vegetation structure, but creates favorable habitat and food for a few taxa, such as dung beetles. Similarly, grazing-induced structural changes benefit some birds (for foraging, nest sites) while heavy stocking during winter and droughts reduces food for seedeaters and songbirds. With herding and no fences, wildlife (herbivores and predators) thrives on nutritious regrowth while having access to large undisturbed areas. It is concluded that ReGM does not universally promote biodiversity but can be adapted to provide greater landscape habitat heterogeneity suitable to a wider range of biota.

Fusing Sentinel-1 and -2 to Model GEDI-Derived Vegetation Structure Characteristics in GEE for the Paraguayan Chaco

Vegetation structure is a key component in assessing habitat quality for wildlife and carbon storage capacity of forests. Studies conducted at global scale demonstrate the increasing pressure of the agricultural frontier on tropical forest, endangering their continuity and biodiversity within. The Paraguayan Chaco has been identified as one of the regions with the highest rate of deforestation in South America. Uninterrupted deforestation activities over the last 30 years have resulted in the loss of 27% of its original cover. The present study focuses on the assessment of vegetation structure characteristics for the complete Paraguayan Chaco by fusing Sentinel-1, -2 and novel spaceborne Light Detection and Ranging (LiDAR) samples from the Global Ecosystem Dynamics Investigation (GEDI). The large study area (240,000 km²) calls for a workflow in the cloud computing environment of Google Earth Engine (GEE) which efficiently processes the multi-temporal and multi-sensor data sets for extrapolation in a tile-based random forest (RF) regression model. GEDI-derived attributes of vegetation structure are available since December 2019, opening novel research perspectives to assess vegetation structure composition in remote areas and at large-scale. Therefore, the combination of global mapping missions, such as Landsat and Sentinel, are predestined to be combined with GEDI data, in order to identify priority areas for nature conservation. Nevertheless, a comprehensive assessment of the vegetation structure of the Paraguayan Chaco has not been conducted yet. For that reason, the present methodology was developed to generate the first high-resolution maps (10 m) of canopy height, total canopy cover, Plant-Area-Index and Foliage-Height-Diversity-Index. The complex ecosystems of the Paraguayan Chaco ranging from arid to humid climates can be described by canopy height values from 1.8 to 17.6 m and canopy covers from sparse to dense (total canopy cover: 0 to 78.1%). Model accuracy according to median R² amounts to 64.0% for canopy height, 61.4% for total canopy cover, 50.6% for Plant-Area-Index and 48.0% for Foliage-Height-Diversity-Index. The generated maps of vegetation structure should promote environmental-sound land use and conservation strategies in the Paraguayan Chaco, to meet the challenges of expanding agricultural fields and increasing demand of cattle ranching products, which are dominant drivers of tropical forest loss.

Influence of vegetation structure, seasonality, and soil physical properties on rodent species diversity and community assemblages on West Mount Kilimanjaro, Tanzania.

A study on rodent species diversity and community assemblages in West Mt Kilimanjaro was conducted in seven different habitats, covering two dry and wet seasons. Data were collected using a combination of medium-sized Sherman’s live traps, snap and Havarhart traps, for three consecutive nights. General Linear Models (GLM) were used to analyze the effects of predictors (vegetation attributes, seasonality, soil physical properties, disturbance and altitude) on rodent species richness and abundance. Community structure analysis was conducted in the Primer v6 program and Canonical correspondence analysis for habitat association in PAST. A total of 1,393 individuals from 14 species of rodents were trapped. The most dominant rodent species were Rhabdomys pumilioPraomys delectorum, and Lophuromys verhageni which contributed to 68.86% of the total captures. Lophuromys verhageni occurred across all the habitats and seasons. Moreover, habitat types, seasonality, soil texture, ground cover, and altitude significantly influenced rodent species abundance (P< 0.05). Furthermore, habitat types, seasonality and altitude significantly influenced rodent species richness (F8, 759 = 629.7, p< 0.001, R2 = 0.87). In addition to that, two major rodent communities were formed in different habitats. The results show that rodent species richness, abundance, and community assemblages in Mt Kilimanjaro, are a result of change in vegetation structure along the altitudinal gradients. Therefore, information on habitat requirements of multiple species is crucial for the management and conservation of these communities.

Spatial distribution of halophytes and environment factors in salt marshes along the eastern Yellow Sea

Background Salt marshes provide a variety of ecosystem services; however, they are vulnerable to human activity, water level fluctuations, and climate change. Analyses of the relationships between plant communities and environmental conditions in salt marshes are expected to provide useful information for the prediction of changes during climate change. In this study, relationships between the current vegetation structure and environmental factors were evaluated in the tidal flat at the southern tip of Ganghwa, Korea, where salt marshes are well-developed. Results The vegetation structure in Ganghwa salt marshes was divided into three groups by cluster analysis: group A, dominated by Phragmites communis; group B, dominated by Suaeda japonica; and group C, dominated by other taxa. As determined by PERMANOVA, the groups showed significant differences with respect to altitude, soil moisture, soil organic matter, salinity, sand, clay, and silt ratios. A canonical correspondence analysis based on the percent cover of each species in the quadrats showed that the proportion of sand increased as the altitude increased and S. japonica appeared in soil with a relatively high silt proportion, while P. communis was distributed in soil with low salinity. Conclusions The distributions of three halophyte groups differed depending on the altitude, soil moisture, salinity, and soil organic matter, sand, silt, and clay contents. Pioneer species, such as S. japonica, appeared in soil with a relatively high silt content. The P. communis community survived under a wider range of soil textures than previously reported in the literature; the species was distributed in soils with relatively low salinity, with a range expansion toward the sea in areas with freshwater influx. The observed spatial distribution patterns may provide a basis for conservation under declining salt marshes.

Assessment of Vegetation Structure of the African Buffalo (Syncerus caffer) Habitat in Kainji Lake National Park, Nigeria

The study assessed the relative abundance and vegetation structure of African buffalo (Syncerus caffer) including plant parameters: frequency, diameter at breast height (dbh), tree height, diversity, evenness, richness, Margalef, dominance in Kainji Lake National Park. Point – Centered Quarter method was used for woody species enumeration. A total of twenty-eight (28) randomly sampled plots of 150m by 100m given 112 points per plot were established in the study area. The abundance and distribution, tree frequencies, heights, dbh and plant biodiversity indices were calculated using the Paleontological Statistics Software (PAST) for scientific data analysis. The results revealed that relative abundance of African buffalo in both morning and evening of dry and wet seasons in various habitats of the Park were 13.33 ± 4.41 and 11.33 ± 4.40 respectively. The study showed the highest mean value of 21.75 ± 6.94 representing 87 individuals in dry season compared to wet season with mean value of 15.25 ± 5.11 representing 61 individuals. A total of 91 woody plant species and 29 tree families were recorded in African buffalo habitats representing 80, 77, 68 and 59 tree species respectively. The highest average girth size of tree species was class between >10cm -50cm with 59.14 ± 4.06 and the highest mean tree height was height class of >3 - 10m with 91.43 ± 5.44. There were significant differences at (p<0.05) between the values of dbh, tree height, diversity, richness and evenness of plant species recorded in different habitats studied in the Park.