Habitat Structure Research Articles

Impacts of fire and prospects for recovery in a tropical peat forest ecosystem

Uncontrolled fires place considerable burdens on forest ecosystems, compromising our ability to meet conservation and restoration goals. A poor understanding of the impacts of fire on ecosystems and their biodiversity exacerbates this challenge, particularly in tropical regions where few studies have applied consistent analytical techniques to examine a broad range of ecological impacts over multiyear time frames. We compiled 16 y of data on ecosystem properties (17 variables) and biodiversity (21 variables) from a tropical peatland in Indonesia to assess fire impacts and infer the potential for recovery. Burned forest experienced altered structural and microclimatic conditions, resulting in a proliferation of nonforest vegetation and erosion of forest ecosystem properties and biodiversity. Compared to unburned forest, habitat structure, tree density, and canopy cover deteriorated by 58 to 98%, while declines in species diversity and abundance were most pronounced for trees, damselflies, and butterflies, particularly for forest specialist species. Tracking ecosystem property and biodiversity datasets over time revealed most to be sensitive to recurrent high-intensity fires within the wider landscape. These megafires immediately compromised water quality and tree reproductive phenology, crashing commercially valuable fish populations within 3 mo and driving a gradual decline in threatened vertebrates over 9 mo. Burned forest remained structurally compromised long after a burn event, but vegetation showed some signs of recovery over a 12-y period. Our findings demonstrate that, if left uncontrolled, fire may be a pervasive threat to the ecological functioning of tropical forests, underscoring the importance of fire prevention and long-term restoration efforts, as exemplified in Indonesia.

Habitat Selection of Three Neotropical Grassland Birds Is Dependent on Vegetation Structure and Resources

Grassland birds are globally imperiled. Those of endemic Neotropical savannas may be particularly threatened as knowledge of the ecology of many species is lacking, restricting our ability to take decisive conservation action. During the dry (non-breeding) season of 2010, we studied the population size, distribution, and habitat associations of the Cock-tailed Tyrant (Alectrurus tricolor), Black-masked Finch (Coryphaspiza melanotis), and Wedge-tailed Grass-finch (Emberiziodes herbicola) across a disturbance-mediated savanna–grassland gradient in Beni, Bolivia. We used distance sampling and surveyed structural and resource-specific habitat features at plots where birds were present versus random locations. Occupancy models identified fine-scale habitat associations. Cock-tailed Tyrant (7.1 ind./km2) specialized on open habitats in areas expected to be heavily inundated in the wet season, avoided trees, and selected tall grassy swards. Black-masked Finch (25.1 ind./km2) occurred across the gradient, associating with tall, forb-rich swards, sparse shrubs, and low levels of fruiting and seeding vegetation. Wedge-tailed Grass-finch (27.9 ind./km2) also occurred across the gradient, particularly associated with tall, forb-rich swards, abundant seeding grasses, and sparse shrubs. Our results offer the first quantitative abundance estimates for these species in Beni, provide vital baselines for future monitoring, and improve knowledge of the ecology and conservation management needs of these species. Importantly, our results suggest that populations of these three grassland birds may be best maintained in heterogenous, mosaic landscapes that can be produced by carefully managed burning and grazing. Further research in the breeding season would facilitate making stronger, more specific management recommendations.

Ponto-Caspian amphipod co-location with zebra mussel beds (Dreissena polymorpha) is influenced by substrate size and population source

The global spread of non-native species is leading to an increasing frequency of multiple co-occurring non-native species. We examined the co-occurrence of the bivalve mollusc Dreissena polymorpha (zebra mussel) with three Ponto-Caspian amphipods (Dikerogammarus villosus, Dikerogammarus haemobaphes, and Chelicorophium curvispinum) across England and Wales in association with in-situ substrate size. For all three amphipod species, substrate grain size where amphipods co-occurred with D. polymorpha was significantly finer than when recorded in isolation. Subsequently, we confirmed this via aquarium experiments. We examined the occurrence of D. villosus with D. polymorpha when present with cobbles, gravel, or sand from three population sources (co-location with abundant D. polymorpha populations, co-location with low populations, and naïve). Experiments demonstrated that D. villosus actively sought shelter on or near D. polymorpha, with their co-location being significantly more prevalent in finer grained substrates (sand > gravel > cobble). The strength of this co-location differed by population source, with those co-located with high D. polymorpha densities demonstrating a greater association. Our analyses and experiments indicate that D. polymorpha may facilitate Ponto-Caspian amphipod establishment in otherwise suboptimal locations, whereby mussel shells provide favourable structural habitat for the amphipods, analogous to the presence of coarse-grained benthic sediment.

Unveiling the avian community structure, habitat preference, and conservation concerns in the sal forest of central bangladesh

A study on avifaunal diversity was conducted in Bhawal National Park, Gazipur, Bangladesh, from November 2020 to October 2021 using direct field observation. The study area was divided into five sites based on the habitat structure. A total of 138 bird species and 1,808 individuals were directly counted, representing 17 orders and 49 families. The order Passeriformes and the family Cuculidae had the highest number of species. During the winter season, the richness, abundance, and diversity was the maximum (116 species, 1132 individuals, H= 4.151, Ds= 0.976), with resident bird surpassing migratory species. Among the five study sites, the deep forest area exhibited the greatest number of bird species (75 species, H= 3.983, Ds= 0.975) and trees were the used microhabitat for the birds (101 species, 1521 individuals, H= 4.1, Ds= 0.977). Jungle Babbler (Turdoides striata) had the maximum relative abundance and the ten most abundant species constituted 36.7% of total individuals. A total of 25 habitat generalist species was observed using more than one habitat during the study, while the rest were found in single habitat. Among all the bird species, 136 were Least Concern, one was Near Threatened, and one was Data Deficient. Based on the observation status, it was determined that the majority of bird species (97 species, 70.28%) were classified as few, while 25 species (18.11%) were as uncommon, 12 species (8.69%) as common, and 4 species (2.89%) as very common. The area was noted for its widespread use for recreational activities, and the disturbance caused by visitors lacking awareness poses a significant threat to the local bird population and biodiversity.
 Dhaka Univ. J. Biol. Sci. 33(1): 1-21, 2024 (January)

Rodent communities in a neglected grassland landscape: Investigating species-specific responses of grassland rodents to habitat type and shrub presence

Arid grasslands worldwide are transitioning to scrublands due to shrub encroachment, resulting in habitats with varying shrub cover. Shrubs play a crucial role in grassland ecosystems, offering trade-offs to rodents in terms of visibility, shelter, and food availability, thereby affecting their occurrence and distribution. This study explores the link between habitat characteristics and rodent activity and density, focusing on shrub presence. In the Tirunelveli district of southern India, we measured rodent density and activity across three grassland types with increasing shrub presence. Our findings reveal species-specific responses to shrub density. The Soft-furred rat (Millardia meltada) dominated, showing adaptability to different shrub levels, while the black rat (Rattus Rattus) was least represented. Fine-scale analysis indicates a positive association between shrub presence and rodent captures. Grassland obligate species like the Indian gerbil (Tatera indica) exhibited reduced activity in densely shrubbed sites, whereas semi-arboreal species like the Indian palm squirrel (Funumbulus palmarum) showed increased activity. This study underscores the importance of considering habitat structure in grassland ecosystem management for the conservation of rodent diversity and ecosystem health.

Characterizing landscape fragmentation of Koitobos river sub-basin, Trans-Nzoia, Kenya

The changes in landscape structure and functioning due to unprecedented human interference are hastening across the globe and it is thus a compelling necessity to preserve and restore our ecosystems. This study aimed to characterize levels of landscape fragmentation, habitat structure, driving forces, and perceptions of the residents on the most preferred reconfiguration approaches. The land use/land cover [LULC] change was first determined by interpreting the 1973, 1986, 1995, 2002, 2014, and 2022 Landsat images using the QGIS 3.26 while the selected landscape fragmentation metrics were analyzed using FRAGSTATS 4.2. Forests, shrubs, and grasslands showed a declining trend, except for agriculture, water, and built-up areas, which depicted high increases for the study periods [1973 to 2022]. The landscape of the study area is characterized as progressively fragmenting as signified by high escalated values of patch number [374 %], edge density [7828 %] between 1986 and 2002, contagion [10.3%], and a declined value of Shannon Diversity Index [SHDI] [-17.42%], Shannon evenness index [SHEI] [-25.8 %] and connectedness [-43.3%]. Considering these results, high losses of forests and grasslands coupled with expansive farmlands and built-up areas have led to unprecedented landscape fragmentation From field surveys and oral interviews, this has not only left streams vulnerable to massive sediment loads but has also triggered annual floods which occur during wet months even though change in onset of rainfall seasons was also reported. The findings call for restoration and integrated and sustainable restoration efforts, especially for the forests, grasslands, and riparian corridors along with sustainable urban planning and community-based sensitization on watershed management.

The effect of planting grass filter strips on fishes in agricultural headwater streams

Abstract Grass filter strips (i.e., herbaceous riparian buffers) are a widely used conservation practice in the United States to mitigate the impacts of agriculture on streams and rivers. Yet, only a limited amount of information is available on the effects of grass filter strips on stream fishes and instream habitat conditions and long‐term assessments are rare. The objective of this research was to document the long‐term effects of planting grass filter strips adjacent to channelized agricultural headwater streams on fish community structure and instream habitat. Fishes, instream habitat and riparian characteristics were sampled from three channelized agricultural headwater streams without grass filter strips, three channelized agricultural headwater streams with grass filter strips and two unchannelized streams having forested riparian habitats in central Ohio from spring of 2006 to autumn of 2015. Fish species richness, abundance, darter species richness, per cent darters, sunfish species richness, minnow species richness and per cent headwater fishes did not differ among riparian habitat types. Darter species richness and per cent darters differed annually. Mean water depth, velocity, wetted width, instream habitat diversity, dominant grain size and per cent instream wood did not differ among riparian habitat types. Mean water depth, water velocity, wetted width and instream habitat diversity exhibited annual differences. Additionally, mean riparian width, woody vegetation density and per cent canopy cover were greater in forested streams than the unplanted and grass filter strip streams. Riparian characteristics did not differ annually. The lack of fish community responses 10–13 years after planting grass filter strips is probably due to the lack of corresponding changes in hydrological characteristics, substrate and instream wood amounts. These results suggest that grass filter strips should not be implemented alone but in conjunction with conservation practices that will improve physical habitat quality and water quality.

Microhabitats shape ant community structure in a spatially heterogeneous grassy woodland

AbstractHabitat structure is a key determinant of local animal diversity, with attributes of vegetation such as cover or complexity generating key resources for different species. However, habitat–diversity relationships can vary across spatial scales, and among different taxa and ecosystem types. Here we report on a study of habitat structure and its effects on ant communities at two spatial scales in a temperate grassy woodland characterized by heterogenous tree and grassland cover. We examined species richness and the occurrence of ground‐dwelling ant species at (1) microhabitat scales defined by a triplet of sites comprising open ground, adjacent to a log, and under a tree, each separated by a few meters, and (2) at macrohabitat scales defined by sites grouped into broader vegetation types defined by low or high levels of shrub and tree cover and separated by 100s of meters. We identified 117 species of ant from 41 genera, from a total of 155,004 individuals collected. Ant community composition differed significantly among microhabitats and macrohabitats, but mean species richness only differed at the microhabitat scale where it was the highest under trees and lower adjacent to logs and in open ground. Notably, ant species within the genera Iridomyrmex, Monomorium, and Pheidole displayed a spectrum of microhabitat preferences, highlighting the ecological flexibility within these groups. By contrast, all species of Melophorus preferred open habitat and all species of Camponotus preferred habitat under trees. Our study shows that ant communities in grassy woodlands are structured by vegetation cover and habitat “openness” most strongly at “microhabitat” scales, which is likely due to a distinct combination of thermal and foraging attributes that vary across relatively small distances. Our results also suggest that broad classifications of ants into functional types based on vegetation preference may not be applicable at small scales where species within the same genus can display contrasting preferences. Land management that promotes habitat heterogeneity at small spatial scales may promote species coexistence and benefit ant diversity more than management activities focusing on larger spatial scales within the same ecosystem.

Ecological Status of Treehopper Caresa tuarina in District Hyderabad, Sindh Pakistan

The treehopper, also known as Caresa tuarina, is an intriguing creature with more than a hundred recorded species. Treehoppers are a very diverse group of insects, that play a crucial role in the ecosystem, yet many species remain uncovered in terms of their ecological status. Objectives: To investigate the ecological status of C. taurina and propose conservation strategies to ensure its preservation in the district Hyderabad, Sindh, Pakistan. Methods: Field survey was carried out in different areas of Hyderabad to investigate the habitat and population of C. tuarina. For preservation of C. taurina specie, naphthalene balls and 70% alcohol were used. Environmental factors including temperature, humidity, plant cover, air pressure, soil type, and UV index and habitat structure were noted at each sample location. Results: The collected treehoppers were small size insects, measuring around 8 mm in length. Agricultural areas and riparian zones were shown to be important habitats for C. taurina populations. Different physical characteristics included soil type was lay and whose terrain was plane land; there was a full moon, 34°C in the mean temperature; 27% Mean humidity; 21.22 psig of air pressure; and a moderate UV index. Urbanization, intensified agriculture, pesticide usage, and changes in habitat appropriateness brought on by climate change are the main causes of habitat degradation for populations of C. taurina. Conclusions: It is concluded that population of treehoppers (C. tuarina) mostly found in agriculture and riparian zones. They are facing habitat degradation as a result of urbanization, intensive agriculture, pesticide use, and changes in habitat appropriateness brought on by climate change.

Influence of Ductility on the Performance of Lunar Habitat Structures Under Recurrent Disturbances

This research examines how ductility affects the durability of lunar surface structures against recurring disturbances like moonquakes, micrometeorite impacts, and thermal cycles over an extended period. The structural performance at various levels of ductility was determined by adjusting material parameters and the thickness of a reference multilayered dome structure. Moonquake and micrometeorite impact-induced lateral displacements were estimated using a reduced-order model under a control-oriented dynamic computational modeling framework. The study considered the degradation of the metallic dome’s strength properties over time due to thermal cycles. Fragility curves were generated by assessing the likelihood of reaching three predefined damage levels as a result of multiple hazards. Additionally, a discounted cash flow analysis was conducted to incorporate a financial aspect into the performance comparison. The findings revealed that structures with sufficient ductility capacity have a lower probability of sustaining severe damage or collapsing within a shorter time frame. Hence, having ductile structures in lunar environments is advantageous as it allows the postponement of maintenance and repair actions, thereby conserving scarce resources for more urgent tasks. Moreover, the financial analysis demonstrated that lunar habitats with higher ductile capacities result in larger net present values, offering a higher return on the initial investment.

Rehabilitation of tropical urban streams improves their structure and functioning

Urban streams are affected by a complex combination of stressors, which modify physical habitat structure, flow regime, water quality, biological community composition, and ecosystem processes and services, thereby altering ecosystem structure and functioning. Rehabilitation projects have been undertaken in several countries to rehabilitate urban streams. However, stream rehabilitation is still rarely reported for neotropical regions. In addition, most studies focus on structural aspects, such as water quality, sediment control, and flood events, without considering ecosystem function indicators. Here, we evaluated the structure and functioning of three 15-y old rehabilitated urban stream sites in comparison with three stream sites in the best available ecological condition (reference), three sites with moderate habitat alteration, and three severely degraded sites. Compared to degraded streams, rehabilitated streams had higher habitat diversity, sensitive macroinvertebrate taxa richness, and biotic index scores, and lower biochemical oxygen demand, primary production, sediment deposition, and siltation. However, rehabilitated streams had higher primary production than moderate and reference streams, and lower canopy cover, habitat diversity, sensitive macroinvertebrate taxa richness, and biotic index scores than reference streams. These results indicate that rehabilitated streams have better structural and functional condition than degraded streams, but do not strongly differ from moderately altered streams, nor have they reached reference stream condition. Nonetheless, we conclude that rehabilitation is effective in removing streams from a degraded state by improving ecosystem structure and functioning. Furthermore, the combined use of functional and structural indicators facilitated an integrative assessment of stream ecological condition and distinguished stream conditions beyond those based on water quality indicators.

Human disturbance and habitat structure drive eurasian otter habitat selection in heavily anthropized river basins

Assessing habitat selection is essential to protecting threatened species but also to understand what factors influence species that, although globally not currently in decline, act as flagships of their ecosystems and remain highly vulnerable to human impacts, such as the Eurasian otter. This paper examines otter habitat selection at the river reach scale in two heavily anthropized river basins. Both river basins encompass a wide spectrum of human pressures and biogeographic units, which offers an excellent opportunity to assess otter responses to anthropogenic activities in different scenarios. Through two modelling approaches (structure-agnostic way and a priori hypothesized habitat factors) we demonstrate that otters currently inhabiting these human-dominated landscapes show a trade-off between a preference for highly productive areas and for well-structured and safe areas. We suggest that habitat simplification and human disturbance, which were of minor relevance to the dramatic decline of otter populations in the 20th century, are emerging as potential threats in the context of worldwide increasing land use intensification. Furthermore, we found that otter habitat requirements were remarkably more stringent for breeding site selection than for occurrence, particularly concerning variables related to human disturbance. The results of this work provide tools for integrating ecological criteria oriented to effective otter conservation into river management in human-dominated landscapes, as well as serving as methodological support for lowland river restorations. Our results suggest that long-term otter conservation in anthropized rivers will depend on ensuring the availability of habitat patches that maintain sufficient structural complexity away from intensely outdoor recreational activities.

Management practices, and not surrounding habitats, drive bird and arthropod biodiversity within vineyards

Agrochemical use and habitat loss associated with agriculture are drivers of biodiversity loss worldwide, and biodiversity-friendly farming practices, including organic management, are increasingly promoted by policy and industry in an attempt to offset this. Grapes are an important perennial crop globally, and in the UK, viticulture is the fastest growing agricultural sector and sustainable vineyard management is promoted by the Sustainable Wines of Great Britain ‘SWGB’ scheme. Here, we performed the first assessment of the simultaneous effects of surrounding habitats and vineyard management practices on bird and arthropod biodiversity across 22 English vineyards (10 certified-organic, 11 SWGB-accredited, and 3 both). We surveyed birds using point counts and arthropods with pitfall traps, and used linear mixed modelling to relate diversity and abundance to habitat and management predictors at landscape and local scales. We show that arthropod abundance is significantly higher on organic vineyards, whilst bird diversity is significantly lower on SWGB-accredited vineyards, but we find no other significant effects of organic certification or SWGB-accreditation on biodiversity. We also find no significant effects of the surrounding habitat structure on the biodiversity of birds and arthropods. Instead, we show that ecotoxicity scores derived from agrochemical use data have a significant negative impact on bird diversity, and on arthropod abundance and diversity. Organic status predicts a significant reduction in ecotoxicity scores, but only when application frequency is not considered, and contradictorily, SWGB-accredited vineyards have higher ecotoxicity scores than those without accreditation. Ground vegetation cover has a consistent, positive effect on bird and arthropod diversity, with model predicted diversity increasing 1.5 and 2.5-fold, respectively, in vineyards with the highest vegetation cover, and herbicide use has a negative effect on the vegetation cover. Our research demonstrates that individual management practices have a stronger effect on vineyard biodiversity than the habitat context, overall management regime or certification. Our study sets an important baseline for vineyard management and accreditation schemes and generates key recommendations for improvement. To benefit biodiversity within vineyards, we recommend that sustainability accreditation schemes include requirements to reduce the ecotoxicity of used agrochemicals, and promote higher ground vegetation cover and height by reducing herbicide use.

Two-stage channels can enhance local biodiversity in agricultural landscapes

Field drainage causes habitat loss, alters natural flow regimes, and impairs water quality. Still, drainage ditches often are last remnants of aquatic and wetland habitats in agricultural landscapes and as such, can be important for local biodiversity. Two-stage channels are considered as a greener choice for conventional ditches, as they are constructed to mimic the structure of natural lowland streams providing a channel for drainage water and mechanisms to decrease diffuse loading. Two-stage channels could also benefit local biodiversity and ecosystem functions, but existing information on their ecological benefits is scarce and incomplete. We collected environmental and biological data from six agricultural stream systems in Finland each with consequent sections of a conventional ditch and a two-stage channel to study the potential of two-stage channels to enhance aquatic and riparian biodiversity and ecological functions. Biological data included samples of stream invertebrates, diatoms and plants and riparian beetles and plants. Overall, both section types were highly dominated by few core taxa for most of the studied organism groups. Riparian plant and invertebrate communities seemed to benefit from the two-stage channel structure with adjacent floodplains and drier ditch banks. In addition, two-stage channel sections had higher aquatic plant diversity, algal productivity, and decomposition rate, but lower stream invertebrate and diatom diversity. Two-stage channel construction did not diversify the structure of stream channels which is likely one explanation for the lack of positive effects on benthic diversity. However, both section types harbored unique taxa found only in one of the two types in all studied organism groups resulting in higher local gamma diversity. Thus, two-stage channels enhanced local biodiversity in agricultural landscapes. Improvements especially in aquatic biodiversity might be achieved by increasing the heterogeneity of in-stream habitat structure and with further efforts to decrease nutrient and sediment loads.

Vertical habitat preferences shape the fish gut microbiota in a shallow lake.

Understanding the interactions between fish gut microbiota and the aquatic environment is a key issue for understanding aquatic microorganisms. Environmental microorganisms enter fish intestines through feeding, and the amount of invasion varies due to different feeding habits. Traditional fish feeding habitat preferences are determined by fish morphology or behavior. However, little is known about how the feeding behavior of fish relative to the vertical structure in a shallow lake influences gut microbiota. In our study, we used nitrogen isotopes to measure the trophic levels of fish. Then high-throughput sequencing was used to describe the composition of environmental microbiota and fish gut microbiota, and FEAST (fast expectation-maximization for microbial source tracking) method was used to trace the source of fish gut microbiota. We investigated the microbial diversity of fish guts and their habitats in Lake Sanjiao and verified that the sediments indeed played an important role in the assembly of fish gut microbiota. Then, the FEAST analysis indicated that microbiota in water and sediments acted as the primary sources in half of the fish gut microbiota respectively. Furthermore, we classified the vertical habitat preferences using microbial data and significant differences in both composition and function of fish gut microbiota were observed between groups with distinct habitat preferences. The performance of supervised and unsupervised machine learning in classifying fish gut microbiota by habitat preferences actually exceeded classification by fish species taxonomy and fish trophic level. Finally, we described the stability of fish co-occurrence networks with different habitat preferences. Interestingly, the co-occurrence network seemed more stable in pelagic fish than in benthic fish. Our results show that the preferences of fish in the vertical structure of habitat was the main factor affecting their gut microbiota. We advocated the use of microbial interactions between fish gut and their surrounding environment to reflect fish preferences in vertical habitat structure. This approach not only offers a novel perspective for understanding the interactions between fish gut microbiota and environmental factors, but also provides new methods and ideas for studying fish habitat selection in aquatic ecosystems.

Distribution of the critically endangered fan mussel Pinna nobilis population in the Çanakkale Strait and Marmara Sea

This study was conducted with the primary objective of determining the presence of both healthy and impacted Pinna nobilis populations along the European coasts of the Sea of Marmara, followed by the identification of P. nobilis abundance and survival rates in the region encompassing the Çanakkale Strait and the southern coasts of the Sea of Marmara. Underwater surveys were randomly conducted at 19 distinct stations, including 8 stations along the European coasts of the Sea of Marmara, 7 stations along the southern coasts of the Sea of Marmara, and 6 stations within the Çanakkale Strait. SCUBA diving equipment was utilized to record information on habitat structure, water temperature, depth, and visibility at each station. The transect length during underwater surveys and the number of transects at each station were determined based on the condition of the seabed and the size of the area, respectively. Throughout the study period (September 2021 and October 2023), water temperature fluctuated between 17.5°C and 26.6°C. At the end of the study, a total of 395 individuals (147 live, 248 dead) were observed, with live individuals exhibiting total lengths ranging from 16.4 cm to 50.9 cm. This study represents the first investigation into the spatial distribution of P. nobilis along the European coast of the Marmara Sea. The study contributes significantly to enhancing our understanding of the ecology of P. nobilis populations in both the Sea of Marmara and the Çanakkale Strait. Additionally, recommendations for the rehabilitation of impacted populations and the conservation of healthy populations have been provided for decision-makers and fisheries managers.

Seasonal and Ecological Determinants of Wild Boar Rooting on Priority Protected Grasslands

Wild ungulates can influence various trophic levels, regulating carnivore abundance and affecting habitat structure. Conservation problems can arise when high ungulate densities threaten species or habitats with conservation concern. Assessing factors influencing the intensity of their impact is important to identify appropriate measures enhancing habitat conservation. We assessed factors influencing wild boar Sus scrofa pressure on EU protected grasslands in three protected areas of central Italy, by modelling the effects of environmental variables and wild boar density on rooting activity. We seasonally estimated rooting in 126 sampling plots from spring 2019 to spring 2021, and we used faeces counts to estimate summer wild boar densities. Estimates of density and rooting varied from 3.5 to 22.2 individuals/km2 and from 1.1 to 19.2%, respectively. We detected a clear seasonal trend in rooting activity, that peaked in autumn and winter. We also found a strongly positive correlation between spring-summer rooting and summer density, across sites. Rooting intensity was negatively related to the local extent of rock cover and increased with the 1 month-cumulative rainfall, the perimeter of the grassland patch, and the forest cover around plots. These results emphasise the tendency of wild boar to exploit feeding sites in ecotonal areas, i.e., at the interface between forest and meadows, which maximises security and ease of finding food resources. Actions aiming at the protection of focal plants in grassland habitats, as well as reducing wild boar presence, are supported (e.g. fencing and/or targeting population control at vulnerable patches).

Habitat and Population Structure of Five Multipurpose Species in Forest Management Site of Tiogo, Burkina Faso

Understanding the dynamics of multipurpose species in savanna ecosystems is essential for their sustainable conservation. This study aims to assess the population structure of five target species (<i>Tamarindus indica,</i> <i>Vitellaria paradoxa,</i> <i>Detarium microcarpum</i>, <i>Anogeissus leiocarpa,</i> and <i>Crossopteryx febrifuga</i>) in the forest management site of Tiogo. Floristic inventory was conducted on 100 plots of 1000 m2. Non-Metric Multidimensional Analysis was carried out to characterized the target species’ habitats. A total of 70 species distributed in 23 families and 55 genera were recorded. Four groups of overlapping plant communities were identified. Each group constitutes a habitat of target species with diverse ecological drivers. Weibull distribution showed an overall good population structure for <i>Vitellaria paradoxa</i>, <i>Detarium microcarpum</i> and <i>Crossopteryx febrifuga</i>. However, <i>Tamarindus indica</i> and <i>Anogeissus leiocarpa</i> showed bad regeneration potential with lack of recruitment in the smaller diameter size classes. It is therefore important to increase the monitoring in the forest management site. This work has provides valuable information for better management of target species, aiding in effective forest management of Tiogo, subject to anthropic pressures.

Anatomically modern human dispersals into Europe during MIS 3: Climate stability, paleogeography and habitat suitability

The initial large-scale dispersal of Anatomically Modern Humans (AMHs) into Europe, associated with the Aurignacian technocomplex, occurred during Marine Isotope Stage 3 (MIS 3), a critically unstable climatic period. The impact of climate change (millennial-scale Dansgaard-Oeschger events) and climate variability (annual and seasonal variation) on the mobility and initial dispersal of AMHs on the continent is not fully demonstrated. Here we show that both climate change and variability affected the spatial behavior of Aurignacian groups and structured their arrival on the continent. Using Random Forest, a machine learning algorithm, we produced habitat suitability (HS) models for AMHs under stadial (GS) and interstadial (GI) climate conditions. These models demonstrate that climate variability was a key factor governing the spatial behavior of human groups across MIS 3. They also illustrate that the structure and distribution of suitable habitat in Europe were affected by climatic conditions, with implications in terms of our species’ adaptability and behavioral plasticity. Finally, our results support the suggestion that initial dispersals followed a Mediterranean coastal route, likely under interstadial conditions.

Difference in acoustic responses to urbanisation in two African passerines

Modification of ecosystems as a consequence of urbanisation alters natural habitat structures and soundscapes, creating constraints for vocal communication in animals. Birds are able to adjust their vocalisation to the prevailing acoustic features of their habitat. As such, their sounds have been shown to reflect the level of anthropogenic disturbances across landscapes. While the effect of a single anthropogenic disturbance like ambient noise on birds’ vocal communication is widely investigated, the combined effects of various disturbances remain less explored. We tested single and combined effects of anthropogenic noise and urban physical structures on the vocalisations of two African passerines, the Common Bulbul Pycnonotus barbatus and Northern Grey-headed Sparrow Passer griseus. We predicted that (i) both species would increase the minimum frequency of their vocalisation to avoid masking by ambient noise, (ii) both species would decrease their maximum frequency to evade distortion by physical structures, (iii) the two urban components would have a significant combined effect on the vocalisations, and (iv) the change in minimum or maximum frequency will lead to a corresponding change in the vocalisation bandwidth. For the Common Bulbul, the minimum frequency increased significantly as the ambient noise level increased, but the maximum frequency did not change in response to urban physical structures. For the Northern Grey-headed Sparrow, the minimum frequency did not show a response to ambient noise, but the maximum frequency decreased significantly as physical structures and ambient noise increased. We did not find any evidence for a combined effect of urban physical structures and ambient noise on the vocal adjustment of either species. A change in either the minimum or maximum frequency resulted in a corresponding change in the vocalisation bandwidth of each species. Our findings highlight how the same vocalisation traits of different songbird species can be affected differently by novel selective pressures in acoustic communication that arise in urban environments.