Modeling the short-term fire effects on vegetation dynamics and surface energy in southern Africa using the improved SSiB4/TRIFFID-Fire model

Fire causes abrupt changes in vegetation properties and modifies flux exchanges between land and atmosphere at subseasonal to seasonal scales. Yet these short-term fire effects on vegetation dynamics and surface energy balance have not been comprehensively investigated in the fire-coupled vegetation model. This study applies the SSiB4/TRIFFID-Fire (the Simplified Simple Biosphere Model coupled with the Top-down Representation of Interactive Foliage and Flora Including Dynamics with fire) model to study the short-term fire impact in southern Africa. Specifically, we aim to quantify how large impacts fire exerts on surface energy through disturbances on vegetation dynamics, how fire effects evolve during the fire season and the subsequent rainy season, and how surface-darkening effects play a role besides the vegetation change effects. We find fire causes an annual average reduction in grass cover by 4 %–8 % for widespread areas between 5–20∘ S and a tree cover reduction by 1 % at the southern periphery of tropical rainforests. The regional fire effects accumulate during June–October and peak in November, the beginning of the rainy season. After the fire season ends, the grass cover quickly returns to unburned conditions, while the tree fraction hardly recovers in one rainy season. The vegetation removal by fire has reduced the leaf area index (LAI) and gross primary productivity (GPP) by 3 %–5 % and 5 %–7 % annually. The exposure of bare soil enhances surface albedo and therefore decreases the absorption of shortwave radiation. Annual mean sensible heat has dropped by 1.4 W m−2, while the latent heat reduction is small (0.1 W m−2) due to the compensating effects between canopy transpiration and soil evaporation. Surface temperature is increased by as much as 0.33 K due to the decrease of sensible heat fluxes, and the warming would be enhanced when the surface-darkening effect is incorporated. Our results suggest that fire effects in grass-dominant areas diminish within 1 year due to the high resilience of grasses after fire. Yet fire effects in the periphery of tropical forests are irreversible within one growing season and can cause large-scale deforestation if accumulated for hundreds of years.

Conservation of endemic lizards in New Zealand cities

<p>Globally, biodiversity is in crisis. One contributing factor is the rapid urbanisation of the world’s population. Land cover change associated with urbanisation radically alters ecosystems, making them uninhabitable for many species. Additionally, people who live in cities often have reduced contact with nature and there are fears that a lack of nature experience may diminish concern for the environment and biodiversity among urbanites. For these reasons, people in cities are increasingly being encouraged and empowered to reduce environmental impacts and connect with nature through urban restoration and backyard conservation. Internationally, lizards are a common feature of urban biodiversity but in New Zealand, where many species are threatened, little is known about populations of endemic skinks and geckos in cities. In order to effectively manage urban lizard populations, greater knowledge is needed about where and how lizards are surviving in cities, and what potential exists for their restoration. I investigated species diversity and abundance of lizards in New Zealand cities, making comparisons with historical species distributions to inform urban restoration and investigating the potential role that participatory conservation might play in their protection. To collate current knowledge about past and present distributions of urban-dwelling lizards, I reviewed records for six New Zealand cities from published and unpublished literature and databases. Little research was identified from cities and the majority of lizard records were of one-off sightings, or surveys related to salvage or biosecurity operations. Comparing current species records with historical species distributions, it found that the diversity of lizards in all of the cities has declined dramatically since human colonisation. To begin to fill the identified knowledge gap and to provide baselines for future monitoring, I carried out skink surveys in four cities and trialled a citizen science project that collected public sighting records from residential backyards. Surveys undertaken in urban habitats captured four species of endemic skink: Oligosoma aeneum in Hamilton, O. polychroma, O. aeneum and O. ornatum in Wellington, O. polychroma in Nelson, and O. aff. polychroma Clade 5 in Dunedin. Site occupancy and number of captures were highly variable among the species and cities, with a very high proportion of sites occupied by skinks in Nelson and Wellington compared with Hamilton and Dunedin. Modelling showed O. polychroma catch per unit effort was positively related to rat tracking rates when grass cover was low but showed a negative relationship when grass cover was high. Higher proportions of urban land cover within 500 m were negatively associated with body condition. The public sightings website gathered more than 100 records from around the Wellington region over one summer, suggesting citizen science may be a cost-effective solution for building knowledge about lizards in residential gardens that are otherwise difficult to survey. While skink sightings were reported from all over the city, gecko sightings appeared in clusters. Compared with a random sample of street addresses, both skink and gecko sightings were more common closer to forest land cover, but only skink sightings were more common in backyards that were north facing. Finally, I administered a questionnaire survey to understand how socio- demographic characteristics relate to willingness to engage in three different pro-conservation activities that might benefit lizards: pest mammal trapping, biodiversity monitoring and pest mammal monitoring. Public willingness to engage in all three activities was positively related to respondents’ nature relatedness and nature dosage, while only the two monitoring activities were positively related to education. The relationship between willingness and nature relatedness was weaker for pest trapping than it was for the two monitoring activities, suggesting that willingness to trap may be determined by factors other than environmental concern. Native lizards are an important component of New Zealand’s urban biodiversity. Despite cities having lost significant proportions of their original lizard fauna, a wide variety of habitats in cities still support numerous species. Some of these species seem well adapted to cope with the challenges of urban living, while further research is required to understand whether populations of other species are stable or in decline. To ensure the persistence of lizards in cities, further surveys using a variety of methods should be undertaken to assess lizard diversity and abundance in urban habitats and understand population trends of rare and sparsely distributed species. Public sightings may provide a useful starting point for assessing distribution patterns and allowing the targeting of surveys. In the future, through urban restoration, cities may offer opportunities to conserve a larger proportion of endemic species by reintroducing species that have become regionally extinct.</p>

Conservation of endemic lizards in New Zealand cities

<p>Globally, biodiversity is in crisis. One contributing factor is the rapid urbanisation of the world’s population. Land cover change associated with urbanisation radically alters ecosystems, making them uninhabitable for many species. Additionally, people who live in cities often have reduced contact with nature and there are fears that a lack of nature experience may diminish concern for the environment and biodiversity among urbanites. For these reasons, people in cities are increasingly being encouraged and empowered to reduce environmental impacts and connect with nature through urban restoration and backyard conservation. Internationally, lizards are a common feature of urban biodiversity but in New Zealand, where many species are threatened, little is known about populations of endemic skinks and geckos in cities. In order to effectively manage urban lizard populations, greater knowledge is needed about where and how lizards are surviving in cities, and what potential exists for their restoration. I investigated species diversity and abundance of lizards in New Zealand cities, making comparisons with historical species distributions to inform urban restoration and investigating the potential role that participatory conservation might play in their protection. To collate current knowledge about past and present distributions of urban-dwelling lizards, I reviewed records for six New Zealand cities from published and unpublished literature and databases. Little research was identified from cities and the majority of lizard records were of one-off sightings, or surveys related to salvage or biosecurity operations. Comparing current species records with historical species distributions, it found that the diversity of lizards in all of the cities has declined dramatically since human colonisation. To begin to fill the identified knowledge gap and to provide baselines for future monitoring, I carried out skink surveys in four cities and trialled a citizen science project that collected public sighting records from residential backyards. Surveys undertaken in urban habitats captured four species of endemic skink: Oligosoma aeneum in Hamilton, O. polychroma, O. aeneum and O. ornatum in Wellington, O. polychroma in Nelson, and O. aff. polychroma Clade 5 in Dunedin. Site occupancy and number of captures were highly variable among the species and cities, with a very high proportion of sites occupied by skinks in Nelson and Wellington compared with Hamilton and Dunedin. Modelling showed O. polychroma catch per unit effort was positively related to rat tracking rates when grass cover was low but showed a negative relationship when grass cover was high. Higher proportions of urban land cover within 500 m were negatively associated with body condition. The public sightings website gathered more than 100 records from around the Wellington region over one summer, suggesting citizen science may be a cost-effective solution for building knowledge about lizards in residential gardens that are otherwise difficult to survey. While skink sightings were reported from all over the city, gecko sightings appeared in clusters. Compared with a random sample of street addresses, both skink and gecko sightings were more common closer to forest land cover, but only skink sightings were more common in backyards that were north facing. Finally, I administered a questionnaire survey to understand how socio- demographic characteristics relate to willingness to engage in three different pro-conservation activities that might benefit lizards: pest mammal trapping, biodiversity monitoring and pest mammal monitoring. Public willingness to engage in all three activities was positively related to respondents’ nature relatedness and nature dosage, while only the two monitoring activities were positively related to education. The relationship between willingness and nature relatedness was weaker for pest trapping than it was for the two monitoring activities, suggesting that willingness to trap may be determined by factors other than environmental concern. Native lizards are an important component of New Zealand’s urban biodiversity. Despite cities having lost significant proportions of their original lizard fauna, a wide variety of habitats in cities still support numerous species. Some of these species seem well adapted to cope with the challenges of urban living, while further research is required to understand whether populations of other species are stable or in decline. To ensure the persistence of lizards in cities, further surveys using a variety of methods should be undertaken to assess lizard diversity and abundance in urban habitats and understand population trends of rare and sparsely distributed species. Public sightings may provide a useful starting point for assessing distribution patterns and allowing the targeting of surveys. In the future, through urban restoration, cities may offer opportunities to conserve a larger proportion of endemic species by reintroducing species that have become regionally extinct.</p>

The association of Lantana camara with elephant (Elephas maximus), their food, habitat use and feeding behaviour in southern India

<p>Invasive exotic species pose an enormous threat to the world's biological diversity. Invasions can alter native communities, replacing local biotas with non-indigenous species introduced by humans. Exotic plant invasions can have negative effects on native flora, which can be in turn detrimental to the herbivores that depend on the vegetation. In this dissertation, I examined the association of an exotic invasive weed, Lantana camara L., with the Asian elephant (Elephas maximus), its food resources (grass and browse), habitat use and feeding behaviour in Mudumalai Tiger Reserve, southern India. Exotic plant invasions are often associated with alterations or declines in native floral species. I first examined the association of L. camara and measured environmental covariates with floral species assemblage and richness, elephant browse plants, percentage grass cover and percentage grass occupancy. A multivariate analysis revealed a significant association of L. camara with floral species assemblage and richness, some elephant browse plants and grass cover within the moist deciduous forest (MDF) and dry deciduous forest (DDF), but not in the thorn forest (TF) of Mudumalai. My results suggest that L. camara appears to be capable of altering the floral community in some habitats. These results also suggest that changes in the floral community and a reduction in grass cover due to L. camara invasion could be detrimental to elephant and other herbivores that depend on grass in this reserve. I then examined the association of L. camara with habitat use by elephant. Elephant dung density was used to assess elephant habitat use from 62 line transects, each 1-km in length. I found no evidence that L. camara was associated with elephant habitat use across habitats, although the interaction term between one habitat (DDF) and L. camara was significantly associated with elephant dung density suggesting that the effect of L. camara was different in different habitats. This indicates that L. camara is associated with elephant habitat use within certain habitats. Habitat and impact of human settlements were significantly associated with elephant habitat use across habitats within Mudumalai. In the DDF, however, only L. camara was associated with elephant habitat use. I conclude that while no significant effects of L. camara were seen across habitats, in specific habitats, negative associations of this invasive plant with elephant habitat use, possibly through the reduction of grass cover, are possible. These results indicate that L. camara appears detrimental to elephant in certain habitats and removal of L. camara in these habitats should be prioritised so as to facilitate growth of grass and native browse species, especially if elephant populations continue to expand. Lastly, I examined the association of elephant behaviour, assessed from feeding and stepping rates, with variation in L. camara invasion. Fifty-seven elephants were observed for a total of 64.3 hours using the focal-animal sampling method. Elephant were never observed to feed on L. camara, but rather fed on grass and browse that were present within and around L. camara patches. Feeding rates (number of trunksful·min⁻¹) were negatively associated with L. camara invasion. A path analysis, which assesses both direct and indirect effects of independent variables, indicated that the total effect of L. camara on feeding rates was 11% less than the direct negative association owing to a positive indirect relationship between L. camara and feeding rates through grass cover and browse density. Lantana camara was not significantly associated with variation in stepping rates (number of steps·min⁻¹). Rather, stepping rates were negatively associated with grass cover and positively associated with browse density. My results indicate that L. camara is potentially capable of changing elephant feeding rates, likely through a loss of grass areas due to L. camara invasion. Wild elephants do not eat L. camara, and this invasive plant appears to take the place of an important food source. My results indicate that managers should prioritize their focus on certain habitats to control the impact of L. camara on elephants and vegetation. However, this study was of a correlational nature based on observational data. Experimental work is therefore needed to test for causal relationships among the variables I measured, over multiple seasons and in different habitats. Experimental evidence will enhance our understanding of how invasive weeds modify floral communities, elephant habitat use and behaviour and help determine whether L. camara is a 'passenger' or 'driver' of these changes in this ecosystem.</p>

The association of Lantana camara with elephant (Elephas maximus), their food, habitat use and feeding behaviour in southern India

<p>Invasive exotic species pose an enormous threat to the world's biological diversity. Invasions can alter native communities, replacing local biotas with non-indigenous species introduced by humans. Exotic plant invasions can have negative effects on native flora, which can be in turn detrimental to the herbivores that depend on the vegetation. In this dissertation, I examined the association of an exotic invasive weed, Lantana camara L., with the Asian elephant (Elephas maximus), its food resources (grass and browse), habitat use and feeding behaviour in Mudumalai Tiger Reserve, southern India. Exotic plant invasions are often associated with alterations or declines in native floral species. I first examined the association of L. camara and measured environmental covariates with floral species assemblage and richness, elephant browse plants, percentage grass cover and percentage grass occupancy. A multivariate analysis revealed a significant association of L. camara with floral species assemblage and richness, some elephant browse plants and grass cover within the moist deciduous forest (MDF) and dry deciduous forest (DDF), but not in the thorn forest (TF) of Mudumalai. My results suggest that L. camara appears to be capable of altering the floral community in some habitats. These results also suggest that changes in the floral community and a reduction in grass cover due to L. camara invasion could be detrimental to elephant and other herbivores that depend on grass in this reserve. I then examined the association of L. camara with habitat use by elephant. Elephant dung density was used to assess elephant habitat use from 62 line transects, each 1-km in length. I found no evidence that L. camara was associated with elephant habitat use across habitats, although the interaction term between one habitat (DDF) and L. camara was significantly associated with elephant dung density suggesting that the effect of L. camara was different in different habitats. This indicates that L. camara is associated with elephant habitat use within certain habitats. Habitat and impact of human settlements were significantly associated with elephant habitat use across habitats within Mudumalai. In the DDF, however, only L. camara was associated with elephant habitat use. I conclude that while no significant effects of L. camara were seen across habitats, in specific habitats, negative associations of this invasive plant with elephant habitat use, possibly through the reduction of grass cover, are possible. These results indicate that L. camara appears detrimental to elephant in certain habitats and removal of L. camara in these habitats should be prioritised so as to facilitate growth of grass and native browse species, especially if elephant populations continue to expand. Lastly, I examined the association of elephant behaviour, assessed from feeding and stepping rates, with variation in L. camara invasion. Fifty-seven elephants were observed for a total of 64.3 hours using the focal-animal sampling method. Elephant were never observed to feed on L. camara, but rather fed on grass and browse that were present within and around L. camara patches. Feeding rates (number of trunksful·min⁻¹) were negatively associated with L. camara invasion. A path analysis, which assesses both direct and indirect effects of independent variables, indicated that the total effect of L. camara on feeding rates was 11% less than the direct negative association owing to a positive indirect relationship between L. camara and feeding rates through grass cover and browse density. Lantana camara was not significantly associated with variation in stepping rates (number of steps·min⁻¹). Rather, stepping rates were negatively associated with grass cover and positively associated with browse density. My results indicate that L. camara is potentially capable of changing elephant feeding rates, likely through a loss of grass areas due to L. camara invasion. Wild elephants do not eat L. camara, and this invasive plant appears to take the place of an important food source. My results indicate that managers should prioritize their focus on certain habitats to control the impact of L. camara on elephants and vegetation. However, this study was of a correlational nature based on observational data. Experimental work is therefore needed to test for causal relationships among the variables I measured, over multiple seasons and in different habitats. Experimental evidence will enhance our understanding of how invasive weeds modify floral communities, elephant habitat use and behaviour and help determine whether L. camara is a 'passenger' or 'driver' of these changes in this ecosystem.</p>

Invasive Plants Differentially Impact Forest Invertebrates, Providing Taxon-Specific Benefits by Enhancing Structural Complexity

Exotic plant species often negatively affect native herbivores due to the lack of palatability of the invading plant. Although often unsuitable as food, certain invasive species may provide non-nutritional ecological benefits through increased habitat structural complexity. To understand the potential for common invasive forest plant species of the eastern United States to benefit invertebrate communities, we examined the functional and taxonomic community composition of forest insects and spiders in long-term monitoring plots that contained invasive plant species. The extent of invasive plant species ground cover significantly altered spider community composition as categorized by hunting guild. Areas with higher invasive herbaceous and grass cover contained a higher abundance of space web-weaving and hunting spiders, respectively. Spider species richness and total invertebrate abundance also increased with greater invasive grass cover. Still, these trends were driven by just two invasive plant species, garlic mustard and Japanese stiltgrass, both of which have previously been shown to provide structural benefits to native invertebrate taxa. While these two species may improve the structural component of understory forest habitat, many invertebrate groups were not significantly correlated with other prevalent invasive plants and one species, mock strawberry, negatively affected the abundance of certain insect taxa. Particularly in forests with reduced native plant structure, invasive plant management must be conducted with consideration for holistic habitat quality, including both plant palatability and structure.

Natural landscapes state of peasant manor in Astashovo village (Kostroma region) and prospects of their development

The historical information about the village of Astashovo and the owner of the peasant estate M. Sazonov is presented. Detailed information is given about the peculiarities of wooden architecture by the Russian architect I.P. Ropet (Petrov Ivan Nikolaevich, 1845-1908), according to whose sketches and drawings a tower house was built in the village of Astashovo (Ostashevo). The results of landscape analysis of the territory adjacent to the tower house, the former village of Ostashevo, are presented. The data of the inventory of tree plantations and their assortment are presented. Particular attention is paid to the glade, the place where the village was located, and the herbaceous plants that form the glade. Two options for improving the grass cover of the glade near the restored tower house are considered, the substantiation of the selected options is given.

Late Quaternary geochronologic record of soil formation and erosion: Effects of climate change on Mojave Desert hillslopes (Nevada, USA)

Climate change is an often-cited control on geomorphic processes in the arid southwestern United States, but links to direct climatic factors and vegetation change remain under debate. Hillslopes at a site in the eastern Mojave Desert in southern Nevada are mantled by 0–1.5 m of colluvial deposits. Accumulation of weathered bedrock combined with eolian inputs of fine sand and silt led to the formation of well-developed soil profiles. Surface sediments from both sources were incorporated into colluvium, allowing both processes to be dated with optically stimulated luminescence (OSL). OSL ages indicate a period of increased colluviation in the Late Pleistocene facilitated by enhanced bedrock weathering and dust deposition. Hillslope aspect strongly controls predominant soil environments and associated vegetation. Well-developed soils with dense grass cover extensively mantle the mesic north-aspect hillslopes, while more xeric south-aspect hillslopes are dominated by thin colluvium with minimal soil development, extensive bedrock exposure, and desertscrub vegetation. Remnants of older colluvium with moderately developed soils on south aspects, however, indicate they were once more extensively mantled by thicker colluvial deposits. The transition to drier conditions in the Holocene diminished vegetation cover on more xeric south aspects, triggering widespread erosion, whereas the more mesic north aspects retained denser grass cover that minimized erosion. The transition to drier conditions in the Holocene altered the vegetation; however, persistent perennial grass cover minimized erosion into the middle Holocene. Increasing aridity during the middle Holocene significantly reduced grass cover on more xeric south aspects, triggering erosion and alluvial deposition. OSL dates of dust incorporated into terrace sediments indicate late Middle Holocene aggradation and soil development in the Late Holocene. In contrast, maintenance of substantial perennial grass cover on mesic north aspects minimized erosion from those hillslopes throughout the Holocene.

Understanding Grass Invasion, Fire Severity, and Acacia koa Regeneration for Forest Restoration in Hawaiʻi Volcanoes National Park

With invasive grasses increasing wildfire occurrence worldwide, a better understanding of the relationships between native plants, fire, and invasive grass is needed to help restoration plans facilitate ecosystem resilience. Invasive grasses are particularly problematic for altering fire regimes in the tropics, yet in Hawaiʻi, restoration sites are often planted with monocultures of the native tree Acacia koa, which can promote grass growth via nitrogen fixation. This, combined with the difficulty of estimating pre-fire grass cover under thick canopies, complicates attempts to restore Hawaiian ecosystems. We studied the 2018 Keauhou Ranch Fire in Hawaiʻi to investigate three questions: (1) at what level of precision can pre-fire grass cover be accurately estimated from oblique aerial photos? (2) how are post-fire A. koa regeneration densities affected by fire severity? and (3) how are post-fire A. koa regeneration densities affected by pre-fire grass cover and its interaction with fire severity? We collected burn severity and post-fire regeneration data from 30 transects stratified across mid-elevation woodland, montane woodland, and montane shrubland communities. We evaluated visual estimates of pre-fire grass cover from oblique aerial imagery with quantitative in situ data from 60 unburned transects of the same cover types. Pre-fire estimates of grass cover categories were 67% accurate in montane woodland (n = 9) and 100% accurate in montane shrubland (n = 11), but only 20% accurate in mid-elevation woodland (n = 10). In montane woodlands with low pre-fire tree densities, A. koa regeneration densities were higher with increased fire severity, but this trend reversed when pre-fire tree densities were high. We detected no effect of pre-fire grass cover, nor its interaction with fire severity, on A. koa regeneration density. This indicates that restoration through the planting of A. koa may be successful in promoting fire-resilient A. koa forest, although there are potential issues to consider regarding the effects that A. koa’s grass promotion may have on other species within the ecosystem.