Lowland Grassland Research Articles

Marsh Harrier Circus aeruginosus diet and hunting habitat selection in the breeding season: implications for lowland breeding waders

ABSTRACT Capsule A temporal mismatch between peak Marsh Harrier hunting activity and wader chick availability means that in most years waders contribute a negligible component of Marsh Harrier breeding season diet when nesting adjacent to lowland grassland, despite a spatial overlap in their habitat use. Aims To examine the potential for conservation conflict with breeding waders by assessing spatio-temporal patterns in Marsh Harrier hunting activity and examining historical and recent data on Marsh Harrier breeding season diet. Methods We monitored Marsh Harrier hunting behaviour in relation to time-in-season and habitat characteristics, and examined nest hatching records of Marsh Harrier and wader nests (Northern Lapwing Vanellus vanellus, Common Redshank Tringa totanus, Black-tailed Godwit Limosa limosa) for evidence of temporal overlap between hunting peaks and predicted wader chick availability. We also recorded prey provisioning to Marsh Harrier broods using nest cameras (2013–2015) and combined this with Marsh Harrier diet studies across Europe from 1942 to 2016. Results Wader adults and chicks contributed only a small proportion (average 1.5%) to the diet of Marsh Harriers nesting adjacent to breeding wader habitats between 1942 and 2016. This was likely due to a temporal mismatch in the peak of harrier hunting and the predicted availability of wader chicks in most years, despite a spatial overlap in habitat use between wader chick-rearing and Marsh Harrier hunting. Conclusion Conservation conflict between breeding Marsh Harriers and waders on lowland grassland is likely to be minimal in most years, with little evidence of waders as harrier prey items. However, harrier hunting activity increases through the breeding season, driven by the timing of their nesting and chick-rearing, and hunting activity was highest over field centres, where waders breed, so later-nesting wader pairs are still at risk. Wader conservation strategies that encourage survival of early wader nests may therefore limit predation and conservation conflict with Marsh Harriers.

The South American genus Cnemalobus (Coleoptera: Carabidae: Cnemalobini): phylogeny and biogeographic analysis with the description of four new species from extra-Andean Patagonian mountains.

The carabid beetle Cnemalobus Guérin-Ménéville, 1838 inhabits high- and lowland grasslands of southern South America. The highest diversity is found in the Patagonian Steppe, where distribution patterns are associated with latitude and elevation. Northern Patagonia, a large volcanic region with a complex geoclimatic history, exhibits elevated grades of endemism. However, a great deal remains unknown regarding diversification and biogeographical patterns for most of the endemic groups. We describe new Cnemalobus species restricted to isolated volcanoes from these extra-Andean mountain systems. We assess the phylogenetic relationships by updating the phylogeny of the genus and conduct a Bayesian binary Markov chain-Monte Carlo (MCMC) analysis on the resulting phylogenetic tree to discuss the biogeographical distribution patterns. We also provide a taxonomic key to all currently known species of Cnemalobus from the Patagonian Steppe. Our phylogenetic analysis supports the monophyly of the new species Cnemalobus tromen sp. nov., Cnemalobus silviae sp. nov., Cnemalobus aucamahuida sp. nov. and Cnemalobus domuyo sp. nov. grouped with C. diamante and C. nevado , referred to as the 'Extra-Andean' mountain lineage. Biogeographical analysis recognises vicariant events as the most plausible explanation for the allopatric distributions of the new species. We hypothesise that these vicariant events could be related to climatic barriers that likely promoted speciation processes by generating geographical isolation in ancestral populations. Our findings contribute significantly to the biogeographical understanding of the Patagonian volcanic region, prompting new inquiries to unravel the speciation processes of the endemic biota in extra-Andean mountain systems. ZooBank: urn:lsid:zoobank.org:pub:6A7585E8-5006-45BC-A1A3-F874F18A6049.

Restoring landscape burning is compatible with conservation and livestock production in a southeast Australian grassland fragment

Abstract Lowland grassland fragments in southeast Australia are valued for both sheep grazing and conservation. Many fragments are now rarely burnt, despite being shaped by millennia of Aboriginal fire‐use. Restoring fire could potentially reduce fuels, control exotic plant species, promote native species and renew Aboriginal cultural burning. However, this requires understanding of how fire and large herbivores, both native and exotic, are coupled and influence vegetation. We implemented a single round of low‐intensity experimental burns in an area of remnant grassland and patchy eucalypt woodlands in Tasmania that is managed for conservation, albeit intermittently grazed by sheep, as well as by native and exotic wild herbivores. We compared herbivore activity between burnt and unburnt areas over 2 years using cameras and scat transects, and assessed how fire and herbivory influenced herbaceous biomass and the cover of broad vegetation classes with and without herbivore exclusion. Contrary to expectations, burnt areas did not disproportionately attract the main herbivores: domestic sheep, introduced deer and native wallabies. In the predominant grassy sward, grazing and fire both reduced herbaceous biomass but we found no support for our hypothesis that grazing reduces biomass more strongly after burning. This contrasts with isolated patches of Poa tussock grassland, where fire reduced biomass much more strongly than grazing, and grazing effects on biomass were more pronounced following burning. The cover of broad vegetation classes was little affected by burning, but excluding herbivores increased exotic grass cover in both burnt and unburnt plots. Practical implication. In degraded fragments of lowland native grassland, burning and grazing do not necessarily act as strongly synergistic disturbances. Grazing by sheep and wild herbivores can help to control exotic grasses and reduce herbaceous biomass, although burning is much more effective than grazing for reducing biomass of unpalatable Poa tussock grassland. Our results suggest that returning occasional low‐intensity fires to our study system, and other degraded grassland‐woodland fragments, can be compatible with livestock production and conservation goals, but this requires caution and adaptive management.

Can biogeography help bumblebee conservation?

Bumblebees (Bombus Latreille, 1802), because of their large body size, bright colours and activity at times and places that coincide with biologists, are an example of a group of insects that is particularly well represented in museum collections. This is important if taxonomic revisions are to achieve greater comparability among species. Bumblebees have also attracted particular attention because they are especially ecologically and economically valuable for pollination in north temperate regions, where they are now becoming increasingly threatened. I argue that the what, the where, and the how of effective conservation management may be informed by understanding the divergent characteristics that have affected their biogeographical past: by helping us to see ‘the woods’, not just ‘the trees’, of their habitat needs. Identifying suitable habitat should be part of reconstructing historical biogeography within taxonomic revisions. For bumblebees, for example, biogeographical analysis associates major taxonomic groups either with flower-rich lowland grasslands or with flower-rich montane grasslands, highlighting their contrasting requirements for: nest sites, flowers of different depths, pollen-plant families, and especially the differing importance of early spring and late summer flowers for breeding success. This broad view of species groups helps filter the less important idiosyncrasies from local case studies in order to focus conservation actions.

Past climate changes and geographical barriers: the evolutionary history of a subtropical highland grassland species of Solanaceae,Petunia altiplana

AbstractClimate changes and associated glacial and interglacial cycles during the Quaternary strongly influenced the evolutionary history of countless number of species. Subtropical highland grasslands (SHG) in southern South America constitute a distinct vegetation type with high diversity and endemism rates. The most recent common ancestor of the genus Petunia (Solanaceae) originated in lowland grasslands, and some lineages secondarily migrated to SHG. Here, we describe the evolutionary history of an SHG species, P. altiplana, distributed throughout a wide area in a river-fragmented landscape. We used plastid and nuclear markers to evaluate the role of the Pelotas River and Quaternary climate cycles over the genetic structure and historical demography of this species based on a phylogeographical approach. We found moderate population expansions during the last 25 kyr, with a more recent (c. 1.6 kya) divergence between two groups of populations from opposite river margins, possibly caused by the expansion of the Araucaria Forest along the river valley, effectively isolating distinct grassland patches.

Back to the future: Climate change effects on habitat suitability of Parnassius apollo throughout the Quaternary glacial cycles

Abstract Alpine grasslands above the treeline are severely threatened by climate change, mainly due to forest expansion driven by warmer conditions. Analogous lowland grasslands experience severe reductions due to land‐use abandonment and forest encroachment. To address how climate change impacted open‐areas insects, we used Parnassius apollo as a model, a butterfly with wide Palearctic distribution inhabiting both alpine and low‐altitude steppe grasslands. We modelled upper Pleistocene range changes from the Last Interglacial (130 Kya) to the present and future (2050/2070), using medium and high greenhouse gas emission rates for the latter. We combined bioclimatic variables (Worldclim, Paleoclim, Chelsa) with distribution records of P. apollo and two of its most often used larval host plants (Sedum album; Hylotelephium telephium) to formulate species distribution models (SDMs) via the Maximum entropy method. We estimated a substantial range expansion during cold periods (last glacial maximum, 22 Kya) and contractions in warmer periods. Including the host plants in the models brought reduced suitable areas estimate, possibly due to differences in climatic requirements of hosts and the butterfly. Future projections of the extent of suitable climates are surprisingly better than would be expected from a warming climate, likely because the current distribution, especially at lower elevations, is probably restricted by habitat loss due to land abandonment and afforestation. We recommend preventing afforestation in critical habitats across Europe and Asia, and increasing survey activities to perform more accurate SDMs.

Impacts of Livestock Grazing on Vegetation and Soil in Lowland Grassland Ecosystem of Nepal

Livestock grazing is one of the largest sectors for land use globally, and contrasting impacts (negative, neutral, and positive) of livestock grazing on vegetation and soil have been observed. In Koshi Tappu Wildlife Reserve (KTWR), livestock grazing is one of the major problems but has been feebly addressed in previous research. This study, therefore, aims to determine the impacts of livestock grazing on vegetation and soil quality in grasslands of core and buffer zones of KTWR. Less grazing intensity was observed at the core zone compared to the buffer zone. Livestock grazing was observed with negative impacts on the richness and diversity of the plant species causing changes in the community assemblages. Invasive plant species richness, however, was found higher in the low grazed areas. Differences in soil pH, phosphorus, and potassium content between high and low grazed areas were not observed. In contrast, soil electrical conductivity, bulk density, and nitrogen content were significantly higher in the high grazed areas. Controlled grazing is recommended at buffer zone grasslands of KTWR to enhance plant diversity and nutrient availability. The core areas of the reserve should be managed for reducing the abundance and distribution of invasive alien plant species.

Using fertilization rates in semi-natural grasslands to produce seed for ecological restoration

To produce seeds of native species for ecological restoration, cultivating semi-natural grasslands can be a strategy that avoids the environmental impacts of conventional seed propagation and favours the conservation of species-rich grasslands. In a lowland grassland in northern Italy, the effects of three mineral fertilisation treatments (0–0–0, 0–54–108, and 192–108–216 kg ha−1 year−1 of N, P2O5, and K2O; abbreviations: 000, 0pk, and NPK) on seed production were studied in a fully randomised block design. Fertile shoots of flowering species were collected and analysed for seed content, and species phenology was recorded during field observations. The grassland environmental quality was described based on soil analyses and indices of natural (plant and insect richness) and aesthetic (flower colour) value. NPK produced the highest viable seed amount (59,375 m−2 year−1). The seed mixture was composed mostly of grasses (97%) and included the lowest species number (34). NPK also had the lowest environmental value. In 0pk, the nitrogen from legume rhizobial fixation allowed the production of an intermediate viable seed amount (28,485 m−2 year−1) with an intermediate forb seed percentage (14%) and the highest species number in the vegetation (42) and collected as seeds. In 000, the seed amount was the lowest (8310 m−2 year−1), but the species number (40) and forb percentage in the seed mixture (39%) were high. The natural and aesthetic values did not significantly differ between 0pk and 000. The P soil content increased strongly in NPK, whereas decreases or insignificant increases in P and K were recorded in 0pk and 000. Mineral 0pk fertilisation allows for relatively high seed production with high legume and forb richness by avoiding the distribution of nitrogen fertilisers that potentially impact the environment. This strategy seems to be a good option for producing environmentally friendly seed mixtures of many native species from semi-natural grasslands.

When did bumblebees reach South America? Unexpectedly old montane species may be explained by Mexican stopover (Hymenoptera: Apidae)

A problem for understanding bumblebee biogeography is that if bumblebees dispersed from Asia through North America to South America, if they are poor at long-distance dispersal with establishment over sea, and if the land bridge between North and South America was not established until c. 3 Ma BP, then there is an apparent conflict with the divergence among currently endemic South American lineages having been dated as early as 15–17 Ma. Using the first complete phylogenetic trees for all known and accepted extant species of the groups involved, we show how this conflict could be resolved. We suggest that characterizing bumblebees as being associated generally with temperate flower-rich meadows conflates divergent habitat specializations between two early lineages, associated with northern lowland grasslands and with southern montane grasslands respectively, which may have driven divergences in behaviour and in biogeographic processes. First, for most of the lowland grassland group of bumblebees, estimated dates of divergence are consistent with dispersal to South America via the land-bridge corridor that opened at c. 3 Ma, followed by extant endemic lineages diverging in situ within South America. In contrast, for the second group that occupies montane grassland habitats (and for a few montane lineages of the ‘lowland’ group), we suggest that dispersal to South America at c. 3 Ma could be consistent with older divergence for currently endemic species if: (1) many of the extant South American lineages had already diverged outside the region before 3 Ma in neighbouring Mesoamerica; and (2) they had been constrained within the high mountains there, dispersing southwards into South America only once the isthmus corridor had become established; and (3) some of those ancestral montane lineages had become extirpated from Mesoamerica during subsequent warm climatic fluctuations. This interpretation re-emphasizes that biogeographic studies need to consider habitat-specific dispersal models that change through time.

Low N2O emissions associated with sheep excreta deposition in temperate managed lowland grassland and extensively grazed hill pasture

Nitrous oxide (N2O) is a potent greenhouse gas (GHG) whose emission from soil can be enhanced by ruminant excretal returns in grasslands. The default (Tier 1) emission factors (EF3PRP; i.e. proportion of deposited nitrogen emitted as N2O) for ruminant excreta deposition are associated with a wide range of uncertainties and the development of country-specific (Tier 2) EF3PRP is encouraged. In Ireland, a Tier 2 EF3PRP has been developed for cattle excreta but no data are available for sheep. The aim of this study was to generate data to contribute to the derivation of a Tier 2 EF3PRP for sheep excreta, while assessing the effect of excreta type, grassland type and season of deposition on N2O emissions. An experiment was carried out on two sites in the west of Ireland: a managed lowland grassland (LOW) and an extensively grazed hill pasture (HILL), characterised by mineral and acid peat soils, respectively. For each season, four treatments were applied to the soil in a fully randomized block design: control (C), sheep urine (U), sheep dung (D), and artificial urine (AU). Nitrous oxide fluxes were assessed over a full year following each application of treatments, using a static chambers methodology. Results showed a brief initial peak following each application of U/AU in LOW but not in HILL. Cumulative N2O emissions were significantly higher from the lowland site. Average EF3PRP for combined excreta was negligible on both sites, thus lower than the IPCC Tier 1 EF3PRP. Causes of low emissions are likely to depend on site characteristics (e.g. soil acidity in HILL) and season of application (i.e. ammonia volatilisation in summer). This study showed very low N2O emissions from sheep excretal returns in Irish grasslands and highlighted the importance of developing Tier 2, animal-specific EF3PRP. More experimental grasslands should be assessed to confirm these results.

Do ditch‐side electric fences improve the breeding productivity of ground‐nesting waders?

Abstract Insufficient reproduction as a consequence of predation on eggs and chicks is a major determinant of population decline in ground‐nesting birds, including waders. For many populations, there is an urgent need to maintain breeding populations at key sites, and conservation practitioners need to find viable management solutions to reduce predation. One tool available to the practitioner is fences that exclude key predators from areas containing breeding birds. Temporary electric fencing is an increasingly popular predator exclusion intervention, but such fences have costs associated with purchase and the time needed to erect and maintain them. Their effectiveness and optimal application are also frequently questioned. We evaluate the use of temporary ditch‐side four‐strand electric fences in lowland grasslands in two countries, The Netherlands and England, in areas containing high densities of breeding waders. In both countries and in all years, godwit and lapwing nest survival was significantly higher within areas enclosed by ditch‐side electric fences. Brood survival, assessed for godwits in The Netherlands, was also higher within fenced areas in all years. This demonstrates that using temporary electric fences to enclose ground‐nesting birds can be an effective tool for improving breeding productivity. In our study, closely managed electric fences were effective at excluding red foxes Vulpes vulpes, but not avian and other mammalian predators. The positive effect that electric fencing had on nest and brood survival therefore likely results from a reduction in the total number of visits by mammalian predators, and especially visits by foxes. Although it requires a substantial time investment throughout the period of use, our temporary electric fence design provides flexibility compared to other fence designs when it comes to enclosing different areas within a season and between years, as the targets for protection change or as land and flood management dictate. This conservation intervention can help buy the time required to develop and implement longer term solutions for application at larger scales.

Areas of endemism and conservation status of Galianthe species (Spermacoceae, Rubiaceae) in the Neotropics

Areas of endemism are a standard unit of biogeography and are commonly used for analytical biogeographic analyses as a criterion to identify areas for conservation. Galianthe is a genus of 56 species of mainly herbaceous plants from the family Rubiaceae found in the Neotropics, occurring in campos rupestres (quartzitic rock outcrops), cerrado (savanna), lowland grasslands, campos de altitude (highland grasslands), sasonally dry tropical forests (caatinga vegetation), and savanna hillsides. Currently, the conservation status assessment is only known for eleven species of Galianthe, and there have been no previous attempts to identify areas of endemism for the genus. In view of this, we used the NDM/VNDM software to analyze the distribution of the 56 species of Galianthe to identify areas of endemism and to recognize which species define each area. We also evaluated the conservation status of forty-five species for first time, according to the International Union for Conservation of Nature (IUCN) guidelines. Our finding identified 12 areas of endemism with three cell sizes, mainly in the eastern part of Paraguay and southern Brazil. Illustrating the general biodiversity crisis, 41% of the Galianthe species (23 spp.), were evaluated as Endangered due to their degree of endemism and destruction of their habitat, while 31 species were evaluated as not threatened and two species had Insufficient Data. In turn, only five threatened species were found within or on the periphery of protected areas. We consider that although protected areas are designed to protect biodiversity, in recent decades they have experienced different degrees of threat. Due to the high risk of many species of the genus, it is necessary to consider restoration (as a complement to conservation) of the processes that maintain grasslands to conserve unique, endemic and threatened species.

Low N2o Emissions Associated with Sheep Excreta Deposition in Temperate Managed Lowland Grassland and Extensively Grazed Hill Pasture

Low N2o Emissions Associated with Sheep Excreta Deposition in Temperate Managed Lowland Grassland and Extensively Grazed Hill Pasture

Grass-shrub coexistence: understanding root distribution in ecological sites of the Semiarid Chaco, Argentina

The objective of this study was to analyze the root distribution of grasses and shrubs, at different soil depths, in two ecological sites (ES): highland (forest) and lowland (grassland). The root density (RD) estimation was used as a proxy to test the two-layer hypothesis. Three trenches were dug in both ES and the number of roots m−2 was registered at different depth classes. The roots were classified in categories: (a) life forms (LF), grasses and shrubs and (b) root size (diameter): fine (<0.1 cm), small (0.11–0.5 cm); medium (0.51–1.5 cm) and large (>1.51 cm). Soil bulk density (Bd) was assessed by gravimetric method and its relation with RD was determined by regression analysis. RD was analyzed by using ANOVA with the factors: ES, LF, depth and root size. There were no significant differences in RD between the ES but RD significantly decreased with depth in both ES. In the upper horizons of the forest, there was higher shrubs RD (764 roots m2) than grass RD (128 roots m2) (p < 0.0001). In grassland, grass RD was registered in all the depths. Mean fine root density was greater than the mean of other root size categories. The relationship between RD and Bd was negative and only significant in the forest (p = 0.009). The distribution of roots of both LF in the soil profile of both ES did not respond completely to the two-layer hypothesis since in upper horizons an overlap was observed.

Quantifying drought effects in Central European grasslands through regression-based unmixing of intra-annual Sentinel-2 time series

Severe droughts caused unprecedented impacts on grasslands in Central Europe in 2018 and 2019. Yet, spatially varying drought impacts on grasslands remain poorly understood as they are driven by complex interactions of environmental conditions and land management. Sentinel-2 time series offer untapped potential for improving grassland monitoring during droughts with the required spatial and temporal detail. In this study, we quantified drought effects in a major Central European grassland region from 2017 to 2020 using a regression-based unmixing framework. The Sentinel-2-based intra-annual time series of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV), and soil fractional cover provide easily interpretable quantities relevant for understanding drought effects on grasslands. Fractional cover estimates from Sentinel-2 matched in-situ conditions observed during field visits. The comparison to a multitemporal reference dataset showed the best agreement for PV cover (MAE = 7.2%). Agreement was lower for soil and NPV, but we observed positive relationships between fractional cover from Sentinel-2 and the reference data with MAE = 10.1% and MAE = 15.4% for soil and NPV, respectively. Based on the fractional cover estimates, we derived a Normalized Difference Fraction Index (NDFI) time series contrasting NPV and soil cover relative to PV. In line with meteorological and soil moisture drought indices, and with the Normalized Difference Vegetation Index (NDVI), NDFI time series showed the most severe drought impacts in 2018, followed by less severe, but persisting effects in 2019. Drought-specific metrics from NDFI time series revealed a high spatial variability of onset, duration, impact, and end of drought effects on grasslands. Evaluating drought metrics on different soil types, we found that grasslands on less productive, sandy Cambisols were strongly affected by the drought in 2018 and 2019. In comparison, grasslands on Gleysols and Histosols were less severely impacted suggesting a higher drought resistance of these grasslands. Our study emphasizes that the high temporal and spatial detail of Sentinel-2 time series is mandatory for capturing relevant vegetation dynamics in Central European lowland grasslands under drought.

Season determines the efficiency of a rapid sampling protocol for non‐acarine arachnids (Chelicerata: Arachnida) in Afrotemperate grassland biotopes

AbstractThe Grassland Biome covers large parts of the inland plateau of South Africa, but many areas have historically been poorly sampled for arachnids. This study aimed to survey non‐acarine arachnids in western KwaZulu‐Natal and compare their biodiversity during winter (June and July 2015) and summer (December 2015 and January 2016). A standardised rapid sampling protocol was used to collect specimens from four biotopes (riparian bush, montane grasslands, lowland grasslands and Eucalyptus plantations). In total, 4623 non‐acarine arachnids were collected, representing five orders, of which 185 spp. were represented by adult specimens (n = 774). Although overall abundance (including immatures) was higher in winter, more adult individuals and species were collected in summer (n = 425, 139 spp.) than in winter (n = 349, 89 spp.). Day hand collecting yielded the highest abundance and species richness during both seasons, and largest number of unique species overall, while Berlese–Tullgren funnels were generally the least efficient method. Seasonal changes in assemblage composition are the result of considerable differences in phenology between the dominant families, resulting in only a small degree of overlap (23.2%) in the adult arachnid fauna between seasons. Several methods collected low adult species richness, but when combined, sample completion values were above 50% for both seasons and overall. This study has highlighted the importance of implementing rapid sampling protocols in multiple seasons to broaden knowledge of local species richness, to effectively address conservation and management objectives.

A decision-making tool for restoring lowland grasslands in Europe

Species-rich grasslands suffer from significant loss and degradation all over the world. In particular in lowland Europe, the vast majority of these habitats are in an unfavourable conservation status which requires urgent restoration measures. A significant amount of information on the results of previous restorations exists thanks to the implementation of numerous projects and the publication of action plans, technical notes and scientific articles. This information is however very scattered, which does not facilitate the work of practitioners. We therefore propose here a decision support tool using a step-wise framework informed by the successes and failures obtained in two large-scale restoration projects supplemented by scientific and grey literature. This decision tree addresses different restoration techniques depending on the local context, e.g. the intensity of habitat degradation, the richness of soil nutrients, and the presence in the vicinity of a habitat in a good conservation status. Depending on the type of grassland, our tool then suggests various recurrent management techniques to be applied after restoration. This synthetic work is presented step by step according to a dichotomous key which is intended to help practitioners make the right choices in their restoration process.

Drought onset and propagation into soil moisture and grassland vegetation responses during the 2012–2019 major drought in Southern California

Abstract. Despite clear signals of regional impacts of the recent severe drought in California, e.g., within Californian Central Valley groundwater storage and Sierra Nevada forests, our understanding of how this drought affected soil moisture and vegetation responses in lowland grasslands is limited. In order to better understand the resulting vulnerability of these landscapes to fire and ecosystem degradation, we aimed to generalize drought-induced changes in subsurface soil moisture and to explore its effects within grassland ecosystems of Southern California. We used a high-resolution in situ dataset of climate and soil moisture from two grassland sites (coastal and inland), alongside greenness (Normalized Difference Vegetation Index) data from Landsat imagery, to explore drought dynamics in environments with similar precipitation but contrasting evaporative demand over the period 2008–2019. We show that negative impacts of prolonged precipitation deficits on vegetation at the coastal site were buffered by fog and moderate temperatures. During the drought, the Santa Barbara region experienced an early onset of the dry season in mid-March instead of April, resulting in premature senescence of grasses by mid-April. We developed a parsimonious soil moisture balance model that captures dynamic vegetation–evapotranspiration feedbacks and analyzed the links between climate, soil moisture, and vegetation greenness over several years of simulated drought conditions, exploring the impacts of plausible climate change scenarios that reflect changes to precipitation amounts, their seasonal distribution, and evaporative demand. The redistribution of precipitation over a shortened rainy season highlighted a strong coupling of evapotranspiration to incoming precipitation at the coastal site, while the lower water-holding capacity of soils at the inland site resulted in additional drainage occurring under this scenario. The loss of spring rains due to a shortening of the rainy season also revealed a greater impact on the inland site, suggesting less resilience to low moisture at a time when plant development is about to start. The results also suggest that the coastal site would suffer disproportionally from extended dry periods, effectively driving these areas into more extreme drought than previously seen. These sensitivities suggest potential future increases in the risk of wildfires under climate change, as well as increased grassland ecosystem vulnerability.

Climate Warming Consistently Reduces Grassland Ecosystem Productivity

AbstractFuture climate may profoundly impact the functioning of terrestrial ecosystems. However, we do not know well how the functioning of different types of grassland ecosystems is associated with variation in temperature and precipitation. Here, we used long‐term field measurements to examine how climatic changes between the 1980s and the 2010s (i.e., growing season temperature, precipitation, habitat moisture index, solar radiation, and sunshine duration) have affected aboveground net primary productivity (ANPP) for all major grassland types in northern China. We found that ANPP consistently declined over the 30‐year period across all types of grassland, on average by about 6.1%. Warming, associated with increased solar radiation and, hence, soil temperature, was the primary factor driving the decrease of ANPP. We further show that ANPP was more sensitive to climate change in alpine and lowland grasslands than in temperate grasslands. Together, our findings indicate that climate warming consistently reduces plant productivity of different types of grassland ecosystems, and emphasize the importance of soil temperature in driving the decline in grassland productivity under climate change.

Land use land cover change and the resilience of social-ecological systems in a sub-region in South west Cameroon.

The old paradigm of horizontal expansion of agricultural land and built-up areas over highland and lowland ecosystems remains highly prevalent in Cameroon, causing significant changes in LULC and undermining the resilience and sustainability of social-ecological systems. We analysed satellite imagery of 1986 and 2018 to examine the extent and spatial patterns of LULCC in Fako sub-region of Cameroon. In addition, we explored the likelihood of LULCC and magnitude of impact of the drivers and predictors of LULCC in the sub-region by engaging 25 stakeholders in a focus group survey. Other cultivated areas of cropland, built-up, oil palm, and banana plantation covers increased by 21,360ha (10.5%), 3152ha (1.6%), 5721ha (2.8%), and 1823ha (0.9%), while dense forest, rubberand tea plantation covers decreased by - 44,945ha (- 22.1%), - 15,557ha (- 7.7%), and - 110ha (- 0.1%), respectively, from 1986 to 2018. Most of the deforestation and LULCC was caused by expansion of other cultivated areas of cropland by smallholders, contrary to the widely publicised narrative of agro-industrial and built-up areas expansion. The spatial pattern of LULCC showed that expansion of other cultivated areas of cropland and agro-industrial plantations were highest in the north and east zones, respectively, while expansion of built-up areas and decrease in agro-industrial plantation covers were highest in the central, south and western coastal zones of Fako division. The variations in the spatial patterns of LULCC between the sub-divisions are attributed to differences in rates of population growth and urbanisation, topography, size of farming population, proportion of cultivable land, socio-economic opportunities, and strength and resilience of local economy. The presence of the Mount Cameroon (4095m), with high value forests, endemism, and conservation attractiveness restricted increased LULCC with elevation, while LULCC increased with nearness to the sea and national road networks. The likelihood of change from one LULC to oil palm plantation, banana plantation, and other cultivated areas and from rubber plantation, dense forest, lowland grassland to other land uses was 95% and 90%, respectively. Population growth, agricultural and farmland expansion, and infrastructural development were ranked asthe three most important drivers of degradation under the business as usual scenario, while sustainable land management, good governance, and reforestation were ranked as thethree most important predictors of LULCC reduction under the green economy scenario. In general, production and living space functions significantly increased at the expense of ecological land cover. Prioritising and increasing the legal protection of the mountain and coastal land-boundary ecosystems while providing for production and living land areinvaluable for the sustainability of the social-ecological systems in the western highlands of Cameroon.