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1
Kavwele, Cyrus M., Johnstone K. Kimanzi, and Mwangi J. Kinyanjui. "Impacts of Bush Encroachment on Wildlife Species Diversity, Composition, and Habitat Preference in Ol Pejeta Conservancy, Laikipia, Kenya." International Journal of Ecology 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/5620125.
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Savannah ecosystems are currently facing a biome shift that changes grasslands to woody dominated landscapes, attributable to habitat degradation. In Ol Pejeta Conservancy (OPC), Euclea divinorum, an unpalatable and invasive woody species, is expanding to former savannah ecosystems with potential effects on herbivores key resources, wildlife species diversity, composition, and habitat use. We investigated wildlife species diversity, composition, and habitat preference or avoidance by wildlife in the conservancy. Infrared camera traps were deployed at the centroids of 2 km by 2 km, 50 cm above ground surface for 14 days and nights with 9 camera traps in each habitat type. Shannon wiener index revealed that wildlife species diversity was highest in E. divinorum dominated habitats and lowest in open grassland. Hierarchical Cluster Analysis revealed level of similarity in wildlife species composition between E. divinorum and mixed bushland. Jacobs index revealed that E. divinorum and mixed bushland were avoided by all guilds; however E. divinorum was significantly avoided while A. drepanolobium and open grassland were both preferred by all guilds. However, A. drepanolobium dominated habitats were significantly preferred compared to open grasslands. The findings are useful in management of sustainable ecosystems.
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Gartzia, Maite, Concepción L. Alados, and Fernando Pérez-Cabello. "Assessment of the effects of biophysical and anthropogenic factors on woody plant encroachment in dense and sparse mountain grasslands based on remote sensing data." Progress in Physical Geography: Earth and Environment 38, no. 2 (April 2014): 201–17. http://dx.doi.org/10.1177/0309133314524429.
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Land abandonment exacerbated by climate change has led to increased woody plant encroachment of mountain grasslands in many regions of the world. The present study assessed woody plant encroachment below potential tree line in the Central Pyrenees of Spain and the association of this encroachment with changes in land use. Remote sensing data from Landsat-5 Thematic Mapper (TM) from the mid-1980s and mid-2000s were analyzed by supervised classification for identification of land cover types. The transition matrix indicated that shrublands were the most dynamic plant communities. Consequently, 21% of cultivated areas, 19% of dense grasslands, and 24% of sparse grasslands became shrublands during the period analyzed, and 35% of shrublands became forest. Generalized additive mixed models (GAMMs) were used to identify biophysical and anthropogenic factors that were significantly correlated with woody plant encroachment of dense and sparse grasslands. Distance to the nearest woody plant habitat (shrub or forest) was the most strongly correlated factor with woody plant encroachment of both types of grassland. This factor explained 69% and 71% of the variance in models of dense and sparse grasslands, respectively. Besides this factor, anthropogenic factors had larger effects on woody plant encroachment of dense grasslands, regions that were more productive and accessible. However, biophysical and especially topographic factors had slightly greater effects on woody plant encroachment of sparse grasslands, regions that were less productive and accessible. The changes in land cover that we observed indicated that land cover has become more homogeneous. There have been reductions in the variety, functions, and services of grasslands, particularly in areas below the potential tree line that are vulnerable to the development of woody plant habitats.
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BAQI, FAZAL. "Distribution and Habitat Selection of Grey Francolin (Francolinus Pondicerianus) in Swegali Game Reserve District Swat, Khyber Pakhtunkhwa, Pakistan." Journal of Bioresource Management 7, no. 4 (December 31, 2020): 27–32. http://dx.doi.org/10.35691/jbm.0202.0148.
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Animals use some habitats and quit others. It is essential to examine resource which is of great interest to the animal for its survival. Distribution and habitat selection of Grey Francolin was examined in Swegali game reserve during June 2007. Twelve line transects 200 meters wide and average 3.73 kilometers long were laid down randomly for collection of data from 06h00-20h00 and observed 58 Grey francolins singly or in pairs. Distributed of Grey francolin was observed in three of the available six habitat types including woody ravines, shrub land and agricultural fields. Chi-squared test showed that Grey francolin displayed significant habitat selection and highly significant preference for woody ravines, northerly aspects and foraged in the morning and evening, a slight drag to the afternoon was also observed. The study can contribute to planning of management interventions for the study species and its preferred habitats. It might assist policy makers to devise policies pertaining to agriculture, study species and their habitats to mitigate encroachment into marginal lands for agriculture, human settlements, use of pesticides and unregulated hunting, assessment of the effects of resource use on wild populations, planning and policy decisions for habitat management and harvest levels.
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Josephson, Rea M. "Economics of Agricultural Encroachment on Wildlife Habitat in Southwest Manitoba." Canadian Journal of Agricultural Economics/Revue canadienne d'agroeconomie 41, no. 4 (December 1993): 429–35. http://dx.doi.org/10.1111/j.1744-7976.1993.tb03767.x.
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Zakkak, Sylvia, John Maxwell Halley, Triantafyllos Akriotis, and Vasiliki Kati. "Lizards along an agricultural land abandonment gradient in Pindos Mountains, Greece." Amphibia-Reptilia 36, no. 3 (2015): 253–64. http://dx.doi.org/10.1163/15685381-00003002.
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Agricultural land abandonment is recognized as one of the main environmental drivers in Southern Europe, affecting ecological communities. Lizards, as ectothermic species with low dispersal capacity, are particularly prone to the threats associated with land use changes. We investigated the effect of land abandonment on lizards in a remote mountainous area in Greece, using line transect sampling, in 20 randomly selected sites [1 km × 1 km], along a four grade abandonment gradient in terms of forest encroachment. We recorded four species: Algyroides nigropunctatus, Lacerta viridis/trilineata, Podarcis tauricus and Podarcis muralis, the latter being the most abundant. Our results did not provide evidence for a significant effect of forest encroachment or grazing on lizard diversity, given the dominance of P. muralis, the availability of all microhabitat types along the gradient and the low grazing intensity in the study area. Environmental parameters at the macrohabitat scale did not prove determinant for habitat variance, but microhabitat analysis showed a clear preference of P. muralis to bare ground. Despite the non-significant effects of land abandonment on lizard diversity, the dominance of P. muralis tends to indicate a lizard community shift towards species inhabiting forested habitats. The preservation of open microhabitats, such as bare land, is considered of great importance for promoting high levels of lizard diversity, as their loss would affect even species currently widespread in forested ecosystems. Low intensity grazing, as well as the enhancement of wild ungulate populations in abandoned areas, can contribute to halting forest encroachment and maintaining the required habitat heterogeneity.
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Wei, Zhenhua, Meng Zheng, Lizhi Zhou, and Wenbin Xu. "Flexible Foraging Response of Wintering Hooded Cranes (Grus monacha) to Food Availability in the Lakes of the Yangtze River Floodplain, China." Animals 10, no. 4 (March 27, 2020): 568. http://dx.doi.org/10.3390/ani10040568.
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Wetlands are disappearing or degrading at an unprecedented rate due to the increase in human encroachment and disturbance, eventually leading to habitat loss for waterbirds, which is the primary cause of the decline in the Hooded Crane (Grus monacha) population. The Hooded Cranes have to constantly adjust their foraging strategies to survive to cope with this situation. In order to study how cranes respond to food resources in mosaic habitat, we surveyed a total of 420 food quadrats and 736 behavioral samples from three habitats during three wintering periods in Shengjin Lake and Caizi Lake. We measured temporal and between-habitat differences in foraging time budget, foraging frequency, and foraging success rate. Akaike’s information criterion was selected between the models of food abundance and availability. The results indicated that the wintering cranes spent the majority of their time (66.55%) foraging and shifted their foraging behaviors based upon food abundance and availability in different habitats. Our analyses also indicated that cranes were willing to forage more food with poor sediment penetrability in sub-optimal habitats. Foraging time budget was based on the food depth, and the foraging frequency and foraging success rate were based on food abundance. Cranes adopted flexible foraging strategies in response to the alternative food resources in mosaic wetland habitats, as it could mitigate the negative impacts of habitat loss and facilitate survival.
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Cabrera-García, Leonardo, José Alejandro Velázquez Montes, and Martha Elena Escamilla Weinmann. "Identification of priority habitats for conservation of the Sierra Madre sparrow Xenospiza baileyi in Mexico." Oryx 40, no. 2 (April 2006): 211–17. http://dx.doi.org/10.1017/s0030605306000615.
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The Sierra Madre sparrow Xenospiza baileyi, categorized as Endangered on the IUCN Red List, is endemic to Mexico. The subalpine bunch grasslands of the Transverse Volcanic Belt in the south of the Valley of Mexico are the last remaining habitat of this species. We conducted a detailed survey for the Sierra Madre sparrow using the point count method, and then described the species' habitat using a phytosociological approach. The two sets of information were pooled into a single analytical framework to identify priority habitats for the species. Eight vegetation communities were distinguished. The Festuca lugens-Muhlenbergia quadridentata and Stipa ichu bunch grassland communities had the highest densities of the Sierra Madre sparrow. Intensive burning and grazing activities and agricultural encroachment have restricted sparrow occupancy. Landscape analysis helped to delineate core grassland areas for the species and grassland strips and islands that could potentially act as habitat corridors. From the information generated in this study, which was shared with the local communities, we are establishing a participatory socio-ecological investigation for conservation of the Sierra Madre sparrow's habitat.
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Gheza, Gabriele, Silvia Assini, Chiara Lelli, Lorenzo Marini, Helmut Mayrhofer, and Juri Nascimbene. "Biodiversity and conservation of terricolous lichens and bryophytes in continental lowlands of northern Italy: the role of different dry habitat types." Biodiversity and Conservation 29, no. 13 (August 18, 2020): 3533–50. http://dx.doi.org/10.1007/s10531-020-02034-1.
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Abstract In dry habitats of European lowlands terricolous lichens and bryophytes are almost neglected in conservation practises, even if they may strongly contribute to biodiversity. This study aims at (a) testing the role of heathlands, acidic and calcareous dry grasslands for lichen and bryophyte diversity and conservation in lowland areas of northern Italy characterized by high human impact and habitat fragmentation; (b) detecting the effect of environmental drivers and vegetation dynamics on species richness and composition. Lichens, bryophytes, vascular plants, and environmental variables were recorded in 287 circular plots for 75 sites. Our results indicate that heathlands, acidic and calcareous dry grasslands host peculiar terricolous lichen and bryophyte communities that include several species of conservation concern. Thus, each habitat provides a complementary contribution to lichen and bryophyte diversity in continental lowland landscapes. Furthermore, in each habitat different factors drive species richness and composition with contrasting patterns between lichens and bryophytes. In terms of conservation, our results indicate that management of lowland dry habitats should act at both local and landscape scales. At local scale, vegetation dynamics should be controlled in order to avoid biodiversity loss due to vegetation dynamics and wood encroachment. At the landscape scale, patches of all the three habitats should be maintained to maximize regional diversity.
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Nel, Lyndre. "Riparian conservation management needs habitat quality mapping." Columella : Journal of Agricultural and Environmental Sciences 7, no. 2 (2020): 15–23. http://dx.doi.org/10.18380/szie.colum.2020.7.2.15.
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Riparian habitat quality has a significant influence on the water quality of rivers, primary resources for urban and agricultural use. River water quality deteriorates where normal ecological functioning is disrupted by harmful impacts from nearby land-use types. Important rivers are typically managed and protected by government-led conservation programs. These programs often lack a key tool for efficient conservation management, habitat quality mapping. The Berg River, an important water source in South Africa, was used as a case-study to assess how habitat quality mapping could broaden the current scope of river conservation programs. The river faces threats from nearby urban settlements, industrial areas, mining, encroachment, and agricultural practices. The aim of this study was to develop habitat quality and habitat degradation maps for a section of the Berg River to assess the value that mapping holds for conservation managers and spatial planners. InVEST modelling software and ArcGIS was used to produce these habitat quality maps based on land-use/land-cover and threat impact data. The resulting maps showed several specific locations of heavily threatened and degraded riparian habitat that had not specifically been included in current government conservation management or spatial planning. Habitat quality mapping is an important tool that conservation managers and spatial planners can use to successfully address habitat degradation and protection while facing resource limitations, such as lack of funding. Oversight of degraded riparian habitats will lead to further decreases in river water quality, adversely affecting human welfare and local economies.
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Chiang, Po-Jen, Kurtis Jai-Chyi Pei, Michael R. Vaughan, Ching-Feng Li, Mei-Ting Chen, Jian-Nan Liu, Chung-Yi Lin, Liang-Kong Lin, and Yu-Ching Lai. "Is the clouded leopard Neofelis nebulosa extinct in Taiwan, and could it be reintroduced? An assessment of prey and habitat." Oryx 49, no. 2 (November 20, 2014): 261–69. http://dx.doi.org/10.1017/s003060531300063x.
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AbstractDuring 1997–2012 we conducted a nationwide camera-trapping survey and assessed the availability of prey and habitat for the clouded leopard Neofelis nebulosa in Taiwan. We surveyed 1,249 camera-trap sites over 113,636 camera-trap days, from the seashore to an altitude of 3,796 m and covering various types of vegetation. No clouded leopards were photographed during 128,394 camera-trap days, including at 209 sites in other studies, confirming the presumed extinction of clouded leopards in Taiwan. Assessment of the prey base revealed altitudinal distribution patterns of prey species and prey biomass. Areas at lower altitudes and with less human encroachment and hunting supported a higher prey biomass and more of the typical prey species of clouded leopards. Habitat analysis revealed 8,523 km2 of suitable habitat but this was reduced to 6,734 km2 when adjacent areas of human encroachment were subtracted. In the absence of hunting and large mammalian carnivores the major prey of clouded leopards in Taiwan, such as Formosan macaques Macaca cyclopis, Reeves's muntjacs Muntiacus reevesi, Formosan serow Capricornis swinhoei and sambar Rusa unicolor, could become over-abundant. Thus, it is important to address the cascading effect of the disappearance of top-down predator control. Our assessment indicated that, with proper regulation of hunting, habitat restoration and corridor improvement, it may be possible to reintroduce the clouded leopard.
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Hoffman, Kira M., Sara B. Wickham, William S. McInnes, and Brian M. Starzomski. "Fire Exclusion Destroys Habitats for At-Risk Species in a British Columbia Protected Area." Fire 2, no. 3 (August 29, 2019): 48. http://dx.doi.org/10.3390/fire2030048.
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Fire exclusion and suppression has altered the composition and structure of Garry oak and associated ecosystems in British Columbia. The absence of frequent low severity ground fires has been one of the main contributors to dense patches of non-native grasses, shrubs, and encroaching Douglas-fir trees in historical Garry oak dominated meadows. This case study uses remote sensing and dendrochronology to reconstruct the stand dynamics and long-term fire history of a Garry oak meadow situated within Helliwell Provincial Park located on Hornby Island, British Columbia. The Garry oak habitat in Helliwell Park has decreased by 50% since 1950 due to conifer encroachment. Lower densities and mortalities of Garry oak trees were associated with the presence of overstory Douglas-fir trees. To slow conifer encroachment into the remaining Garry oak meadows, we recommend that mechanical thinning of Douglas-fir be followed by a prescribed burning program. Reintroducing fire to Garry oak ecosystems can restore and maintain populations of plants, mammals, and insects that rely on these fire resilient habitats.
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Wedekin, Leonardo L., Fábio G. Daura-Jorge, and Paulo C. Simões-Lopes. "Habitat preferences of Guiana dolphins, Sotalia guianensis (Cetacea: Delphinidae), in Norte Bay, southern Brazil." Journal of the Marine Biological Association of the United Kingdom 90, no. 8 (October 4, 2010): 1561–70. http://dx.doi.org/10.1017/s0025315410001414.
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Habitat preference and spatial distribution of Guiana dolphins (Sotalia guianensis) in Norte Bay, southern Brazil, was studied from 2001 to 2005. Boat surveys (N = 91) were made to evaluate the spatial distribution of the dolphins. Seven habitat variables were integrated into a geographical information system, and habitat preference was tested using the ‘Neu method’ and a habitat index. The Guiana dolphins did not use all habitat types in the same proportion as were available. Areas used more intensively included, in order of importance: (1) areas with a steep sloping sea-floor; (2) areas further from urban areas; (3) areas further from mangroves; (4) areas near the mouth of the bay; (5) shallow water areas; (6) areas of clayey-silt sediments; and (7) areas close to shore. From 2001 to 2005 there was a shift in spatial distribution and habitat use by the dolphins. The low frequency of use of areas close to urban encroachment and its related impacts to the marine environment raises concern about the coastal habitat destruction. The Guiana dolphin may be considered a habitat specialist, despite its wide latitudinal distribution in the western Atlantic Ocean. The ecological niche of the species may be defined by a narrow strip of shallow coastal waters (mostly < 30 m) bordering the coastline. The shift in the spatial use was probably linked with changes in the abundance of important prey of the species and possibly was caused by the collapse of a fish stock in the study area region. Different habitats may favour different assemblages of prey and consequently different foraging strategies by the dolphins. Human-related habitat alterations throughout the range of this species are likely to affect dolphins' ecology in many ways and, thus, must be evaluated and mitigated to conserve their critical habitats.
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Ndongo, Pierre A. Mvogo, Thomas von Rintelen, Christoph D. Schubart, Paul F. Clark, Kristina von Rintelen, Alain Didier Missoup, Christian Albrecht, et al. "Discovery of two new populations of the rare endemic freshwater crab Louisea yabassi Mvogo Ndongo, von Rintelen & Cumberlidge, 2019 (Brachyura: Potamonautidae) from the Ebo Forest near Yabassi in Cameroon, Central Africa, with recommendations for conservation action." Journal of Threatened Taxa 13, no. 6 (May 26, 2021): 18551–58. http://dx.doi.org/10.11609/jott.6724.13.6.18551-18558.
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The endemic freshwater crab, Louisea yabassi Mvogo Ndongo, von Rintelen & Cumberlidge, 2019, is currently only known from three populations in the biodiversity-rich rainforests of southwestern Cameroon. The first record of L. yabassi dates back to 1908 from Yabassi, while the other two populations were discovered in December 2019 and March 2020 from the Ebo Forest near Yabassi. These specimens were initially identified as L. edeaensis (Bott, 1969), but were subsequently assigned to L. yabassi. The newly-discovered populations of L. yabassi provided important data on its habitat, population structure and geographical distribution, all critical knowledge for conservation measures. Reported here are the anthropogenic threats to L. yabassi and its rainforest habitat, which include forest destruction, agricultural encroachment, water pollution and firewood collection. This information is inherently useful in the assessment of the extinction risk of L. yabassi and highlights the importance of implementing strategies for preserving primary rainforest and its associated aquatic habitats in Central Africa.
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MAIROTA, PAOLA, VINCENZO LERONNI, WEIMIN XI, DAVID J. MLADENOFF, and HARINI NAGENDRA. "Using spatial simulations of habitat modification for adaptive management of protected areas: Mediterranean grassland modification by woody plant encroachment." Environmental Conservation 41, no. 2 (November 15, 2013): 144–56. http://dx.doi.org/10.1017/s037689291300043x.
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SUMMARYSpatial simulation may be used to model the potential effects of current biodiversity approaches on future habitat modification under differing climate change scenarios. To illustrate the approach, spatial simulation models, including landscape-level forest dynamics, were developed for a semi-natural grassland of conservation concern in a southern Italian protected area, which was exposed to woody vegetation encroachment. A forest landscape dynamics simulator (LANDIS-II) under conditions of climate change, current fire and alternative management regimes was used to develop scenario maps. Landscape pattern metrics provided data on fragmentation and habitat quality degradation, and quantified the spatial spread of different tree species within grassland habitats. The models indicated that approximately one-third of the grassland area would be impacted by loss, fragmentation and degradation in the next 150 years. Differing forest management regimes appear to influence the type of encroaching species and the density of encroaching vegetation. Habitat modifications are likely to affect species distribution and interactions, as well as local ecosystem functioning, leading to changes in estimated conservation value. A site-scale conservation strategy based on feasible integrated fire and forest management options is proposed, considering the debate on the effectiveness of protected areas for the conservation of ecosystem services in a changing climate. This needs to be tested through further modelling and scenario analysis, which would benefit from the enhancement of current modelling capabilities of LANDIS-II and from combination with remote sensing technologies, to provide early signals of environmental shifts both within and outside protected areas.
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Medhi, Dhananjoy, and Bimal Kumar Kar. "Depletion of forest cover and encroachment in Gonbina Reserved Forest in Goalpara district of Assam." Space and Culture, India 4, no. 1 (June 19, 2016): 40. http://dx.doi.org/10.20896/saci.v4i1.187.
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Forests constitute the largest ecosystem and habitat of valuable species of plants and animals on the earth surface. The increasing size of population combined with increasing diversity of human activities is continuously degrading the forest areas of the earth’s surface causing great threat to it in respect of shrinkage of coverage, loss of biodiversity and disturbance in the ecological balance. The intense depletion of forest cover in various parts has also brought about large-scale environmental changes including disappearance of many valuable floral and faunal species. In the said context, the district of Goalpara, located in the western part of Assam, was dominantly covered with dense Sal (Shorea Robusta) forest, widely distributed in both the lowland and hills of the district. However, during last few decades the dense Sal forests of the district have experienced massive depletion because of excessive exploitations and encroachments transforming many patches of forestland treeless and now being used for other purposes. Even the reserved forests are also under acute degradation and encroachment. In this paper, an attempt is made to explore the nature and dimension of forest cover change alongside massive encroachments and associated implications in Gonbina Reserved Forest of Goalpara district, Assam during 1977-2010, with the help of Survey of India toposheet, satellite imagery, field survey and Geographical Information System.
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Holmes, G. I., L. Koloski, and E. Nol. "Nest-site selection of a subarctic-breeding shorebird: evidence for tree avoidance without fitness consequences." Canadian Journal of Zoology 98, no. 9 (September 2020): 573–80. http://dx.doi.org/10.1139/cjz-2019-0264.
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Vegetation communities in the subarctic are at risk of change due to climate-driven tree and shrub encroachment. Vegetation change may lead to unsuitable habitat for arctic-breeding birds, many of whom are declining. Although many possible factors are contributing to their decline, loss of breeding habitat could be a major contributor. We examined nest-site selection in Dunlin (Calidris alpina hudsonia (Todd, 1953)), a shorebird that nests in open fen habitats in the Churchill, Manitoba, Canada, region. Our objective was to determine whether this species avoids treed habitats and the possible fitness consequences for this. We examined the role of vegetative horizontal and vertical concealments on nest-site selection and nest fate. Dunlin selected nest sites with lower densities of trees than present at unused sites (40 m radius). Both horizontal and vertical concealments were significantly greater at nests than at unused sites, and horizontal concealment was greatest in the north. No measure of tree density or height, or concealment, significantly predicted nest fate. Although Dunlin appear to select nest sites that may minimize exposure to northerly winds and that may provide cover against potential predators, the current nest-site characteristics are not reinforced by contemporary selection.
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Rhuemann, Megan, and Sue Wolff. "How are Brewer's Sparrows Affected by the Encroachment of the Exotic Grass Species, Smooth Brome (Bromus Inermis Leyss.)?" UW National Parks Service Research Station Annual Reports 30 (January 1, 2006): 149–52. http://dx.doi.org/10.13001/uwnpsrc.2006.3679.
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Sagebrush habitats (Artemisia spp.) across the western United States have been continuously altered since the arrival of early European settlers. Habitat loss and fragmentation in sagebrush-dominated habitats has been attributed to domestic livestock, introduction of non-native vegetation, agricultural expansion, urbanization, and changes in ecological processes that regulate ecosystems (Knick et al. 2003). These alterations have resulted in landscape level changes; for example, it is estimated that between 50-60% of the nearly 63 million hectares once covered by sagebrush in the west have been either completely converted to non-native grasslands or now contain nonÂnative grasses in the understory (Miller and Eddleman 2001, West 2000 and 1996). The encroachment of non-native plants that compete with native vegetation has been identified as one of the most serious threats to the health and integrity of sagebrush ecosystems throughout the west (Paige and Ritter 1999).
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Kimaro, Houssein Samwel, Ayoub M. Asenga, Linus Munishi, and Anna C. Treydte. "Woody Encroachment Extent and Its Associated Impacts on Plant and Herbivore Species Occurrence in Maswa Game Reserve, Tanzania." Environment and Natural Resources Research 9, no. 3 (July 26, 2019): 63. http://dx.doi.org/10.5539/enrr.v9n3p63.
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Habitat degradation caused by woody plant encroachment has been a common phenomenon in savanna ecosystems. An increasing woody plant cover in open grassland reduces grazing grounds and, consecutively, impacts mammalian herbivores, but structural changes and their associated impact have rarely been assessed and quantified. We analyzed the extent of woody plant encroachment via remote sensing and used transects and plots to assess encroaching woody plant species and their associated impacts on herbaceous plant and herbivore species in Maswa Game Reserve, Tanzania. We found that woody plant cover had increased by 0.5% to 2.6% per annum over the last thirty years, while in other parts of the park it has decreased by 0.5% to 1.5% per annum. Acacia drepanolobium was the dominant encroaching woody species, and the number of stems in heavily encroached sites was seven times and three times higher than in open grassland and at medium encroached sites, respectively. In encroached plots, grazer and mixed feeder species occurrence were reduced while the presence of browser species was slightly elevated. Furthermore, our finding shows that bare ground cover is positively correlated with an increase of woody plant cover. Additionally, the number of herbaceous species slightly increased with the increase of woody plant encroachment, while the herbaceous cover was negatively correlated with the increase of woody plant cover. We suggest that fire regimes should be taken up to suppress the ongoing encroachment processes while strongly encroached sites might need mechanical intervention to control dense vegetation. This emphasis is on fire, particularly prescribed fire as a management tool of vegetation in Savanna ecosystem. We conclude that, woody plant encroachment is driven by different factors such as fire, mega-herbivores and topology that may interactively trigger woody plant encroachment in Savanna ecosystem.
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Dodge, William B., and Daniel M. Kashian. "Recent Distribution of Coyotes Across an Urban Landscape in Southeastern Michigan." Journal of Fish and Wildlife Management 4, no. 2 (September 1, 2013): 377–85. http://dx.doi.org/10.3996/062013-jfwm-040.
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Abstract Human–wildlife interactions in urban areas are widely reported by ecologists to be the result of human encroachment on wildlife habitat. Highly mobile species, however, have been documented by both wildlife biologists and casual observers to occupy areas heavily populated by humans. Range expansion and population growth of coyotes (Canis latrans) has led to their increased presence in metropolitan Detroit, Michigan, where poor economic conditions over the last several decades have resulted in the reversion of numerous recreational areas and abandoned parcels to more wooded or vegetated conditions that have provided potential wildlife habitat. We performed an extensive survey for coyote evidence (i.e., carcasses, den sites, scats, sightings, or tracks) across metropolitan Detroit to examine distribution across both the general region and specific land cover types. We found 58% of all coyote evidence on unpaved trails, paths, and unimproved roads within edge habitats (e.g., grassland adjacent to urban non-vegetative land cover), with den sites and tracks the only types of evidence found strictly in interior habitats. Land cover around evidence points included more wooded land cover than expected in suburban areas, suggesting the importance of tree cover for coyote occupancy, and more open space and wooded land cover than expected in urban areas, highlighting the coyotes' avoidance of heavily populated areas. We speculate that habitat characterized by tree cover has likely never been limiting within metropolitan Detroit, and that reoccupation of southeastern Michigan by coyotes is more likely a consequence of expanding coyote populations outside of suburban and urban areas rather than newly available habitat resulting from land cover change.
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Brandimarti, Maquel E., Rachael Gray, Fabiola R. O. Silva, and Catherine A. Herbert. "Kangaroos at maximum capacity: health assessment of free-ranging eastern grey kangaroos on a coastal headland." Journal of Mammalogy 102, no. 3 (March 30, 2021): 837–51. http://dx.doi.org/10.1093/jmammal/gyab022.
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Abstract Sprawling urban development is fragmenting the landscape and native wildlife habitats on the Australian east coast. The impact of this rapid urbanization on wildlife health is largely unknown. This study surveyed the health of a high-density (5.4 individuals per ha) population of eastern grey kangaroos (Macropus giganteus) affected by urban encroachment and prolonged drought. Blood parameters (hematological and serum protein), trace element and heavy metal concentrations, and parasite counts (fecal worm egg counts, ticks, and mites) are reported for a sample of ≤ 54 kangaroos at Look at Me Now Headland, New South Wales, Australia. These parameters were compared to lower density kangaroo populations from other sites in New South Wales. We found the health and welfare of this population to be severely compromised, with nonregenerative anemia and nutritional deficiencies evident. Our results indicate that high-density kangaroo populations isolated by urban encroachment are at significant health risk. To prevent further decline in this population’s health, we discuss management strategies that could be employed, concurrent with ongoing health and disease monitoring, to mitigate the poor health outcomes in this population. We conclude that it is essential to retain habitat connectivity when altering land use in areas with resident kangaroo populations if managers are to maintain healthy populations.
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Qin, Huang, Liu, Chen, Zhang, Qiu, Tan, and Wen. "The Landscape Patterns of the Giant Panda Protection Area in Sichuan Province and Their Impact on Giant Pandas." Sustainability 11, no. 21 (October 28, 2019): 5993. http://dx.doi.org/10.3390/su11215993.
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As the flagship species of biodiversity conservation in China, the giant panda has significant ecological protection value and plays an important demonstrative role for conservation. Sichuan Province has the largest area of giant panda habitat, making its protected areas the most important for the conservation of this species. However, the habitats of the giant panda are shrinking due to human disturbance through land encroachment for agriculture and other forms of resource exploitation. Reducing these pressures requires assessing current land use and the causes of fragmenting giant panda habitats. This paper reports on changes in land-use patterns and socio-economic development in typical counties with giant panda habitats in Sichuan in 2003 and 2015, with a focus on giant panda protection areas and human pressures in the surrounding lands. We found that road construction, industrial infrastructure, and other forms of economic development have led to increases in human populations and fragmentation of the giant panda habitats, such that that the population of this species has been significantly reduced in some counties. Improving the protection of giant panda requires designing regional economic development activities based on scientific principles to provide benefits to both the local people and the giant pandas. For example, when making land use plans, the local government should consider the impact of the development of the communities surrounding the giant panda areas on the giant pandas’ habitat.
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Alofs, Karen M., and Norma L. Fowler. "Habitat fragmentation caused by woody plant encroachment inhibits the spread of an invasive grass." Journal of Applied Ecology 47, no. 2 (April 2010): 338–47. http://dx.doi.org/10.1111/j.1365-2664.2010.01785.x.
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Schmidt, Paige M., Robert A. McCleery, Roel R. Lopez, Nova J. Silvy, and Jason A. Schmidt. "Habitat succession, hardwood encroachment and raccoons as limiting factors for Lower Keys marsh rabbits." Biological Conservation 143, no. 11 (November 2010): 2703–10. http://dx.doi.org/10.1016/j.biocon.2010.07.016.
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KUBACKA, JUSTYNA, STEFFEN OPPEL, ANDRZEJ DYRCZ, LARS LACHMANN, J. PEDRO DUARTE BARROS DA COSTA, ULLA KAIL, and WANDA ZDUNEK. "Effect of mowing on productivity in the endangered Aquatic Warbler Acrocephalus paludicola." Bird Conservation International 24, no. 1 (March 28, 2013): 45–58. http://dx.doi.org/10.1017/s0959270913000154.
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SummaryThe Aquatic Warbler Acrocephalus paludicola is a globally threatened habitat specialist that breeds in open fens in Central and Eastern Europe. Because bush and reed encroachment threaten many suitable breeding areas, habitat management is necessary to maintain the open wetlands that Aquatic Warblers require for nesting. The effectiveness of mowing as habitat management has so far only been assessed by counting the number of singing males. To assess whether mowing also affected vital reproduction parameters, we analysed Aquatic Warbler productivity in the Biebrza National Park, Poland, on plots in four different successional stages after mowing. Our study showed that productivity was lowest in the first year after mowing, but increased to the highest levels in the second year after mowing. The productivity differences between areas at different stages after mowing resulted from differences in nest density, since we found little evidence for an effect of mowing on nest survival or the number of fledglings produced per successful nest. Nest survival was highly variable between years and varied mostly with nest age and nest initiation date. The density of singing males was positively correlated with both the nest density and the number of fledglings produced in an area, suggesting that this simple indicator could be used to rank the quality of Aquatic Warbler habitats. We recommend that in mesotrophic fen mires, such as the Biebrza valley, mowing as habitat management is applied less frequently than every second year.
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Wilkinson, David A., Jonathan C. Marshall, Nigel P. French, and David T. S. Hayman. "Habitat fragmentation, biodiversity loss and the risk of novel infectious disease emergence." Journal of The Royal Society Interface 15, no. 149 (December 2018): 20180403. http://dx.doi.org/10.1098/rsif.2018.0403.
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The number of microbes on Earth may be 10 30 , exceeding all other diversity. A small number of these can infect people and cause disease. The diversity of parasitic organisms likely correlates with the hosts they live in and the number mammal hosts for zoonotic infections increases with species richness among mammalian orders. Thus, while habitat loss and fragmentation may reduce species diversity, the habitat encroachment by people into species-rich areas may increase the exposure of people to novel infectious agents from wildlife. Here, we present a theoretical framework that exploits the species–area relationship to link the exposure of people to novel infections with habitat biodiversity. We model changes in human exposure to microbes through defined classes of habitat fragmentation and predict that increased habitat division intrinsically increases the hazard from microbes for all modelled biological systems. We apply our model to African tropical forests as an example. Our results suggest that it is possible to identify high-risk areas for the mitigation and surveillance of novel disease emergence and that mitigation measures may reduce this risk while conserving biodiversity.
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Kusumo, Andi, Azis Nur Bambang, and Munifatul Izzati. "Struktur Vegetasi Kawasan Hutan Alam dan Hutan Rerdegradasi di Taman Nasional Tesso Nilo." Jurnal Ilmu Lingkungan 14, no. 1 (April 15, 2016): 19. http://dx.doi.org/10.14710/jil.14.1.19-26.
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ABSTRAK Hutan Tesso Nilo merupakan kawasan dengan tingkat keanekaragaman tanaman berpembuluh dan merupakan habitat bagi satwa terancam punah yaitu harimau sumatera (Panthera tigris sumatrae) dan gajah sumatera (Elephas maximus sumatranus). Kawasan ini tidak luput dari kegiatan perambahan dan di konversi menjadi perkebunan dan permukiman. Pembukaan lahan hutan akan mengakibatkan rusaknya fungsi hutan dan mengakibatkan musnahnya berbagai jenis flora dan fauna. Tujuan penelitian ini adalah untuk mengetahui akibat yang ditimbulkan oleh perambahan hutan terhadap strukur vegetasi kawasan hutan. Metode yang digunakan adalah survei dengan menggunakan sampling vegetasi petak dalam jalur dilokasi hutan alam dan hutan terdegradasi akibat perambahan. Hasil dianalisis untuk mengetahui kelimpahan vegetasi, indeks nilai penting dan indeks keanekaragaman (Shannon-Wiener). Hasil penelitian menunjukkan bahwa perambahan hutan mengakibatkan terjadinya perubahan pada struktur vegetasi. Perambahan mengakibatkan penurunan jumlah kelimpahan vegetasi, nilai keanekaragaman, dan dominansi jenis (indeks nilai penting) baik pada tingkat semai, pancang, tiang dan pohon. Kata kunci: Taman Nasional Tesso Nilo, struktur vegetasi, perambahan ABSTRACT Tesso Nilo forest is an area with a greater diversity of vascular plants and habitat for an endangered species, namely the Sumatran tiger (Panthera tigris sumatrae) and the Sumatran elephant (Elephas maximus sumatranus). This area was not spared from encroachment and conversion to plantations and settlements. Forest clearing will cause damage to forest functions and lead to the extinction of various species of flora and fauna. The purpose of this study was to determine the consequences caused by the encroachment of the structure of forest vegetation. The method used was a survey by sampling vegetation plots in the path of the location of natural forests and forests degraded due to encroachment. The results were analyzed to determine the abundance of vegetation, an index of the importance and diversity index (Shannon-Wiener). The results showed that deforestation resulted in a change in the structure of vegetation. Encroachment degrades an abundance of vegetation, the value of diversity, and dominance type (Importance Value Index) is good for seedlings, saplings, poles and trees. Keywords: Nasional Park of Tesso Nilo, vegetation structure Cara sitasi: Kusumo, A., Bambang, A. N., Izzati, M. (2016). Struktur Vegetasi Kawasan Hutan Alam dan Hutan Rerdegradasi di Taman Nasional Tesso Nilo. Jurnal Ilmu Lingkungan,14(1),19-26, doi:10.14710/jil.14.1.19-26
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Nghikembua, Matti T., Laurie L. Marker, Bruce Brewer, Arvo Leinonen, Lauri Mehtätalo, Mark Appiah, and Ari Pappinen. "Restoration thinning reduces bush encroachment on freehold farmlands in north-central Namibia." Forestry: An International Journal of Forest Research 94, no. 4 (March 27, 2021): 551–64. http://dx.doi.org/10.1093/forestry/cpab009.
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Abstract Bush encroachment affects ~45 million ha of Namibia and, without appropriate restoration measures, it negatively affects rangeland productivity and biodiversity. Thinning is a common method to counteract bush encroachment. The thinning strategy applied in north-central Namibia was assessed to examine how effective it has been in reducing bush encroachment. Trees/shrubs were selectively thinned manually, targeting all height classes, except individuals with stem diameters ≥18 cm. We investigated the effects on the vegetation and soil properties using surveys on three freehold farms (in 2016 and 2017) in bush-encroached and previously thinned habitats. Our results revealed significant differences in the mean total nitrogen (TN) content between the treatments; thinned areas had higher TN content which would be beneficial for fast-growing grasses. In the thinned plots, the occurrence probability of red umbrella thorn (Vachellia reficiens Warwa) was significantly reduced, indicating that it was the most harvested species; and umbrella thorn (Vachellia tortilis (Burch.) Brenan spp. heteracantha) was increased, indicating that it favoured reduced densities of dominant species. Natural regeneration was rapid; the tree/shrub abundance in the 0–1-m height class in the thinned area surpassed those in the non-thinned by 34 per cent, ~7.2 years since thinning. Thinning significantly reduced tree/shrub abundances of the 1–3- and >3-m height classes, which was still evident 7.2 years since thinning. Based upon the generalized linear mixed-effects model, tree/shrub counts between treatments may equalize in ~14 and 15 years for the 1–3- and >3-m height classes, respectively. Thinning was effective in reducing tree/shrub abundances and can be used to restore wildlife habitat on the Namibian farmland: however, post-thinning management is required to maintain an open savannah vegetation structure as the 0–1-m height class cohort will eventually grow into mature trees/shrubs.
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Farren, Aodan, Paulo Prodöhl, Peter Laming, and Neil Reid. "Distribution of the common lizard (Zootoca vivipara) and landscape favourability for the species in Northern Ireland." Amphibia-Reptilia 31, no. 3 (2010): 387–94. http://dx.doi.org/10.1163/156853810791769428.
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AbstractThe common lizard (Zootoca vivipara) is Ireland's only native reptile, forming a key part of the island's biodiversity. However, there is a general paucity of distributional and abundance data for the species. In this study, we collated incidental records for common lizard sightings to define the distribution of the species in Northern Ireland. Maximum entropy modelling was employed to describe species-habitat associations. The resulting predicted landscape favourability was used to evaluate the current status of the species based on the distribution of its maximum potential range in relation to the degree of fragmentation of remaining suitable habitat. In common with previous studies in the Republic of Ireland, sightings were highly clustered indicating under-recording, observer bias, and fragmentation of suitable habitat. A total of 98 records were collated from 1905 to 2009. The species was recorded in 63 (ca. 34%) of 186 × 10 km Northern Irish grid squares. Lizard occurrence was strongly and positively associated with landscapes dominated by heathland, bog and coastal habitats. The single best approximating model correctly classified the presence of lizards in 84.2% of cases. Upland heath, lowland raised bog and sand dune systems are all subject to Habitat Action Plans in Northern Ireland and are threatened by conversion to agriculture, afforestation, invasive species encroachment and infrastructural development. Consequently, remaining common lizard populations are likely to be small, isolated and highly fragmented. Establishment of an ecological network to preserve connectivity of remaining heath and bog will not only benefit remaining common lizard populations but biodiversity in general.
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Burgess, J., K. Szlavecz, N. Rajakaruna, S. Lev, and C. Swan. "Vegetation dynamics and mesophication in response to conifer encroachment within an ultramafic system." Australian Journal of Botany 63, no. 4 (2015): 292. http://dx.doi.org/10.1071/bt14241.
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The biological, ecological, and evolutionary significance of serpentine habitats has long been recognised. We used an integrated physiochemical dataset combining plot spatial data with temporal data from tree cores to evaluate changes in soils and vegetation. Data suggest that this unique habitat is undergoing a transition, endangering local biodiversity and endemic plant species. The objective of this work was to analyse the vegetation dynamics of a xeric serpentine savanna located in the Mid-Atlantic, USA. We employed vegetation surveys of 32 10 × 15 m quadrats to obtain woody species composition, density, basal area, and developed a spatial physiochemical dataset of substrate geochemistry to independently summarise the data using regression and ordination techniques. This information was interpreted alongside historical, dendrochronologic and soil stable carbon isotopic data to evaluate successional dynamics. Comparisons among geologic, pedologic and vegetation environmental drivers indicated broad correlations across an environmental gradient, corresponding to a grassland to forest transition. The woodland communities appear to be part of a complex soil moisture and chemistry gradient that affects the extent, density, basal area and species composition of these communities. Over the gradient, there is an increase in α diversity, a decrease in the density of xeric and invasive species, and an increase in stem density of more mesic species. Dendrochronology suggests poor recruitment of xeric species and concomitant increase in more mesic species. The data indicated that former C4-dominated grasslands were initially invaded by conifers and are now experiencing mesophication, with growing dominance by Acer, Nyssa and more mesic Quercus and Fagus species.
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Bradshaw, Corey J. A., Stan Boutin, Daryll M. Hebert, and A. Blair Rippin. "Winter peatland habitat selection by woodland caribou in northeastern Alberta." Canadian Journal of Zoology 73, no. 8 (August 1, 1995): 1567–74. http://dx.doi.org/10.1139/z95-185.
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Woodland caribou in northeastern Alberta are relatively sedentary, occur at low densities, and are classed as endangered in Alberta. Increasing encroachment of the forest and petroleum industries into the southern regions of the boreal woodland caribou range has highlighted the need for detailed habitat analysis for this species. We obtained approximately 1000 locations of 47 woodland caribou fitted with very high frequency telemetry collars, providing data on winter habitat use from 1991 to 1994. Telemetry data were combined with digital peatland coverages that best represented lowland habitat diversity. Woodland caribou selected forested fen peatland complexes at both the population and individual spatial scales. Woodland caribou concentrated feeding activity in forested, raised bog islands. The raised bogs provide more xeric substrate for increased lichen biomass, possibly a key factor in their selection during winter. The hypothesized connection between discontinuous permafrost and the maintenance of raised bog islands in terms of caribou forage distribution and availability is discussed.
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Bird, Tania L. F., Michael Dorman, Adi Ramot, Amos Bouskila, Pua Bar Kutiel, and Elli Groner. "Shrub Encroachment Effects on Habitat Heterogeneity and Beetle Diversity in a Mediterranean Coastal Dune System." Land Degradation & Development 28, no. 8 (October 13, 2017): 2553–62. http://dx.doi.org/10.1002/ldr.2807.
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April Sahara, E., Daniel A. Sarr, Robert W. Van Kirk, and Erik S. Jules. "Quantifying habitat loss: Assessing tree encroachment into a serpentine savanna using dendroecology and remote sensing." Forest Ecology and Management 340 (March 2015): 9–21. http://dx.doi.org/10.1016/j.foreco.2014.12.019.
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YU, DOUGLAS W., THOMAS HENDRICKSON, and ADA CASTILLO. "Ecotourism and conservation in Amazonian Perú: short-term and long-term challenges." Environmental Conservation 24, no. 2 (June 1997): 130–38. http://dx.doi.org/10.1017/s0376892997000192.
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Several authors have suggested that ecotourism can enhance the value of intact wildlands and thereby promote conservation. Two rainforest lodges dating from the 1970s and located in southeastern Amazonian Perú have been held up as early success stories in tourism-driven conservation, but a more recent assessment reveals that both lodges have since lost their rainforest reserves to encroachment. One of the major reasons for failure was that the national land laws in effect at the time did not allow the purchase of land titles. Recently, Perú has instituted a process for the purchase of land titles in the rainforest. One lodge has used the new land tenure laws with some success to create a rainforest reserve. The very attempt to buy land for purposes of conservation can promote encroachment and land-buying speculation, and the lodge's current agreement with its neighbours to provide a school in exchange for non-encroachment is fraught with moral hazards and appears unstable over the long term. Tourism can promote conservation primarily at the national level, and ecotourism projects in the Peruvian Amazon can stabilize land-use patterns at least in the short term. However, the conservation of habitat over the long-term will rest primarily on the ability of the State to enforce a consistent land use policy with regard to land tenure and Park protection.
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Jung, Thomas S., Michael J. Suitor, Steven Barykuk, Joseph Nuyaviak, Danny C. Gordon, Danny Gordon, Jr., and Ernest Pokiak. "Red Fox (Vulpes vulpes) scavenging on the spring sea ice: potential implications for Arctic food webs." Canadian Field-Naturalist 134, no. 2 (September 21, 2020): 144–46. http://dx.doi.org/10.22621/cfn.v134i2.2375.
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Red Fox (Vulpes vulpes) has been increasingly observed in the Arctic. However, few observations of Red Foxes occupying and using resources on the sea ice have been reported. We observed a Red Fox scavenging on a Polar Bear (Ursus maritimus) carcass on the Beaufort Sea, Northwest Territories, Canada. The fox was in a jumble of ice (i.e., rubble ice) approximately 4.5 km from shore. Local Inuvialuit hunters had also previously observed Red Foxes on the sea ice. Our observation, coupled with those of Inuvialuit hunters, is of interest because it provides additional information on the adaptability of Red Foxes to local environments and their ability to use a wide range of habitats and food sources. Moreover, it points to encroachment by Red Foxes into the offshore habitat of Arctic Foxes (Vulpes lagopus) and potential competition with them for scarce resources, which may impact trophic food webs.
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Neumann, Carsten, Anne Schindhelm, Jörg Müller, Gabriele Weiss, Anna Liu, and Sibylle Itzerott. "The Regenerative Potential of Managed Calluna Heathlands—Revealing Optical and Structural Traits for Predicting Recovery Dynamics." Remote Sensing 13, no. 4 (February 9, 2021): 625. http://dx.doi.org/10.3390/rs13040625.
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The potential of vegetation recovery through resprouting of plant tissue from buds after the removal of aboveground biomass is a key resilience strategy for populations under abrupt environmental change. Resprouting leads to fast regeneration, particularly after the implementation of mechanical mowing as part of active management for promoting open habitats. We investigated whether recovery dynamics of resprouting and the threat of habitat conversion can be predicted by optical and structural stand traits derived from drone imagery in a protected heathland area. We conducted multivariate regression for variable selection and random forest regression for predictive modeling using 50 spectral predictors, textural features and height parameters to quantify Calluna resprouting and grass invasion in before-mowing images that were related to vegetation recovery in after-mowing imagery. The study reveals that Calluna resprouting can be explained by significant optical predictors of mainly green reflectance in parental individuals. In contrast, grass encroachment is identified by structural canopy properties that indicate before-mowing grass interpenetration as starting points for after-mowing dispersal. We prove the concept of trait propagation through time providing significant derivates for a low-cost drone system. It can be utilized to build drone-based decision support systems for evaluating consequences and requirements of habitat management practice.
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McDonald, Andrew T., Amy L. Atwater, Alton C. Dooley Jr, and Charlotte J. H. Hohman. "The easternmost occurrence of Mammut pacificus (Proboscidea: Mammutidae), based on a partial skull from eastern Montana, USA." PeerJ 8 (November 16, 2020): e10030. http://dx.doi.org/10.7717/peerj.10030.
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Mammut pacificus is a recently described species of mastodon from the Pleistocene of California and Idaho. We report the easternmost occurrence of this taxon based upon the palate with right and left M3 of an adult male from the Irvingtonian of eastern Montana. The undamaged right M3 exhibits the extreme narrowness that characterizes M. pacificus rather than M. americanum. The Montana specimen dates to an interglacial interval between pre-Illinoian and Illinoian glaciation, perhaps indicating that M. pacificus was extirpated in the region due to habitat shifts associated with glacial encroachment.
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Rivaes, Rui, Isabel Boavida, José M. Santos, António N. Pinheiro, and Teresa Ferreira. "Importance of considering riparian vegetation requirements for the long-term efficiency of environmental flows in aquatic microhabitats." Hydrology and Earth System Sciences 21, no. 11 (November 22, 2017): 5763–80. http://dx.doi.org/10.5194/hess-21-5763-2017.
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Abstract. Environmental flows remain biased toward the traditional biological group of fish species. Consequently, these flows ignore the inter-annual flow variability that rules species with longer lifecycles and therefore disregard the long-term perspective of the riverine ecosystem. We analyzed the importance of considering riparian requirements for the long-term efficiency of environmental flows. For that analysis, we modeled the riparian vegetation development for a decade facing different environmental flows in two case studies. Next, we assessed the corresponding fish habitat availability of three common fish species in each of the resulting riparian landscape scenarios. Modeling results demonstrated that the environmental flows disregarding riparian vegetation requirements promoted riparian degradation, particularly vegetation encroachment. Such circumstance altered the hydraulic characteristics of the river channel where flow depths and velocities underwent local changes of up to 10 cm and 40 cm s−1, respectively. Accordingly, after a decade of this flow regime, the available habitat area for the considered fish species experienced modifications of up to 110 % when compared to the natural habitat. In turn, environmental flows regarding riparian vegetation requirements were able to maintain riparian vegetation near natural standards, thereby preserving the hydraulic characteristics of the river channel and sustaining the fish habitat close to the natural condition. As a result, fish habitat availability never changed more than 17 % from the natural habitat.
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Bedrosian, Tracy A., Laura K. Fonken, James C. Walton, and Randy J. Nelson. "Chronic exposure to dim light at night suppresses immune responses in Siberian hamsters." Biology Letters 7, no. 3 (January 26, 2011): 468–71. http://dx.doi.org/10.1098/rsbl.2010.1108.
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Species have been adapted to specific niches optimizing survival and reproduction; however, urbanization by humans has dramatically altered natural habitats. Artificial light at night (LAN), termed ‘light pollution’, is an often overlooked, yet increasing disruptor of habitats, which perturbs physiological processes that rely on precise light information. For example, LAN alters the timing of reproduction and activity in some species, which decreases the odds of successful breeding and increases the threat of predation for these individuals, leading to reduced fitness. LAN also suppresses immune function, an important proxy for survival. To investigate the impact of LAN in a species naive to light pollution in its native habitat, immune function was examined in Siberian hamsters derived from wild-caught stock. After four weeks exposure to dim LAN, immune responses to three different challenges were assessed: (i) delayed-type hypersensitivity (DTH), (ii) lipopolysaccharide-induced fever, and (iii) bactericide activity of blood. LAN suppressed DTH response and reduced bactericide activity of blood after lipopolysaccharide treatment, in addition to altering daily patterns of locomotor activity, suggesting that human encroachment on habitats via night-time lighting may inadvertently compromise immune function and ultimately fitness.
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Schroeder, Michael A., Cameron L. Aldridge, Anthony D. Apa, Joseph R. Bohne, Clait E. Braun, S. Dwight Bunnell, John W. Connelly, et al. "Distribution of Sage-Grouse in North America." Condor 106, no. 2 (May 1, 2004): 363–76. http://dx.doi.org/10.1093/condor/106.2.363.
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Abstract We revised distribution maps of potential presettlement habitat and current populations for Greater Sage-Grouse (Centrocercus urophasianus) and Gunnison Sage- Grouse (C. minimus) in North America. The revised map of potential presettlement habitat included some areas omitted from previously published maps such as the San Luis Valley of Colorado and Jackson area of Wyoming. Areas excluded from the revised maps were those dominated by barren, alpine, and forest habitats. The resulting presettlement distribution of potential habitat for Greater Sage-Grouse encompassed 1 200 483 km2, with the species' current range 668 412 km2. The distribution of potential Gunnison Sage-Grouse habitat encompassed 46 521 km2, with the current range 4787 km2. The dramatic differences between the potential presettlement and current distributions appear related to habitat alteration and degradation, including the adverse effects of cultivation, fragmentation, reduction of sagebrush and native herbaceous cover, development, introduction and expansion of invasive plant species, encroachment by trees, and issues related to livestock grazing. Distribución de Centrocercus spp. en América del Norte Resumen. Revisamos los mapas de distribución potencial precolombino y de poblaciones actuales de Centrocerus urophasianus y C. minimus en América del Norte. El mapa modificado de hábitat potencial precolombino incluyó algunas áreas omitidas de mapas anteriormente publicados, como el Valle San Luis de Colorado y el área de Jackson, Wyoming. Las áreas excluídas de los mapas modificados fueron las dominadas por hábitats forestales, alpinos y estériles. La distribución precolombina resultante para C. urophasianus abarcó 1 200 483 km2, con un territorio actual de 668 412 km2. La distribución de habitat potencial para C. minimus abarcó 46 521 km2, con un territorio actual de 4787 km2. Estos contrastes tan marcados parecen estar relacionados con la modificación y degradación del hábitat, incluyendo los efectos nocivos de la agricultura, la fragmentación de hábitat, la disminución de Artemisia spp. y otras coberturas herbáceas nativas, el desarollo, la introducción y la expansión de especies de plantas invasoras, la invasión de árboles y cuestiones relacionadas con pastoreo de ganado.
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Green, Dana M., Nathaniel Mull, Tucker Scolman, Grace Griffiths, and Bret Pasch. "Active space of grasshopper mouse vocalizations (Onychomys) in relation to woody plant encroachment." Behaviour 157, no. 14-15 (November 12, 2020): 1211–29. http://dx.doi.org/10.1163/1568539x-bja10046.
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Abstract The efficacy of animal acoustic communication depends on signal transmission through an oft-cluttered environment. Anthropogenic-induced changes in vegetation may affect sound propagation and thus habitat quality, but few studies have explored this hypothesis. In the southwestern United States, fire suppression and cattle grazing have facilitated displacement of grasslands by pinyon-juniper woodlands. Northern grasshopper mice (Onychomys leucogaster) inhabit regions impacted by juniper encroachment and produce long-distance vocalizations to advertise their presence to conspecifics. In this study, we coupled acoustic recordings and electrophysiological measurements of hearing sensitivity from wild mice in the laboratory with sound transmission experiments of synthesized calls in the field to estimate the active space (maximum distance that stimuli are detected) of grasshopper mouse vocalizations. We found that mice can detect loud (85 dB SPL at 1 m) 11.6 kHz vocalizations at 28 dB SPL. Sound transmission experiments revealed that signal active space is approximately 50 m. However, we found no effect of woody plant encroachment on call propagation because juniper and woody plant density were inversely associated and both present barriers to a 9 cm mouse advertising at ground level. Our data indicate that woody plant encroachment does not directly impact the efficacy of grasshopper mouse communication, but vegetation shifts may negatively impact mice via alternative mechanisms. Identifying the maximum distance that vocalizations function provides an important metric to understand the ecological context of species-specific signalling and potential responses to environmental change.
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Woods, Bonnie A., Janet L. Rachlow, Stephen C. Bunting, Timothy R. Johnson, and Kelly Bocking. "Managing High-Elevation Sagebrush Steppe: Do Conifer Encroachment and Prescribed Fire Affect Habitat for Pygmy Rabbits?" Rangeland Ecology & Management 66, no. 4 (July 2013): 462–71. http://dx.doi.org/10.2111/rem-d-12-00144.1.
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Albrecht, Matthew A., Rachel E. Becknell, and Quinn Long. "Habitat change in insular grasslands: Woody encroachment alters the population dynamics of a rare ecotonal plant." Biological Conservation 196 (April 2016): 93–102. http://dx.doi.org/10.1016/j.biocon.2016.01.032.
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Singh, Bhanwar Vishvendra Raj, and Anjan Sen. "Mapping of Physical Vulnerability in Tiger Habitat Areas: A Case Study of Tiger Corridor of Rajasthan, India." Proceedings of the ICA 2 (July 10, 2019): 1–8. http://dx.doi.org/10.5194/ica-proc-2-118-2019.
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<p><strong>Abstract.</strong> Nowadays, biodiversity is very rapidly diminishing from all over the globe due to unsustainable practices of natural resource by anthropogenic activities. It is an unhealthy for ecosystem services. In the biodiversity, tiger is an icon of healthy wildlife, which is known as a vital factor for maintaining universal food chain system. The research paper is focused on “Mapping of Physical Vulnerability of Tiger Habitat Areas: A Case Study of Tiger corridor of Rajasthan, India” it’s a micro level Study based on primary and secondary data through GIS mapping, habitat ranking and Q-Q plot. All five physical factors to inter-connect and overlay of the ranking of tiger habitats for the physical vulnerability. Especially, core and periphery of vulnerability have obtained from the Multispectral images from ETM and ETM+ sensors of Landsat and LISS-III and AWiFS sensors of Resourcesat-satellites. The study examines the spatial pattern physical vulnerability and suitability of tiger corridor of Rajasthan. Tiger Landscape change within all ecological zones has been evaluated. The Landsat TM and ETM imagery has been used to produce LULC classification maps for both areas utilising a hybrid supervised/unsupervised methods. LULC changes are measured using landscape metrics and change maps created by post-classification through change detection. Using all the raster maps and the final change detection of the reserve has been done through spatial analysis using the raster calculator tool in ArcGIS, Erdas, Statistical tool and MS Excel 13. The study comes out with physical vulnerability in core and periphery areas of the tiger corridor. The research addressed vulnerability of tiger habitat, human encroachment, impact on tiger habitat, intervene of domestic animals, and the migration in core and periphery areas, finally, the situation of physical vulnerability would be alarming for biodiversity of tiger corridor, specially buffer areas.</p>
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Eames, Jonathan C., and Craig R. Robson. "Threatened primates in southern Vietnam." Oryx 27, no. 3 (July 1993): 146–54. http://dx.doi.org/10.1017/s0030605300027940.
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Vietnam's exceptionally rich fauna is threatened by habitat loss and hunting. Although a system of protected areas has recently been developed, many of the sites selected are subject to human encroachment, hunting pressure and other forms of exploitation. Other protected areas may be too small to hold viable populations of primates. Following faunal surveys of existing and proposed protected areas in Vietnam between 1988 and 1991, this paper documents the status of and identifies threats to three species of threatened primate: white-cheeked gibbon Hylobates leucogenys gabriellae, red-shanked douc langur Pygathrix nemaeus and blackshanked douc langur P. nigripes.
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Horton, Kyle G., Benjamin M. Van Doren, Phillip M. Stepanian, Andrew Farnsworth, and Jeffrey F. Kelly. "Where in the air? Aerial habitat use of nocturnally migrating birds." Biology Letters 12, no. 11 (November 2016): 20160591. http://dx.doi.org/10.1098/rsbl.2016.0591.
Full textAbstract:
The lower atmosphere (i.e. aerosphere) is critical habitat for migrant birds. This habitat is vast and little is known about the spatio-temporal patterns of distribution and abundance of migrants in it. Increased human encroachment into the aerosphere makes understanding where and when migratory birds use this airspace a key to reducing human–wildlife conflicts. We use weather surveillance radar to describe large-scale height distributions of nocturnally migrating birds and interpret these distributions as aggregate habitat selection behaviours of individual birds. As such, we detail wind cues that influence selection of flight heights. Using six radars in the eastern USA during the spring (2013–2015) and autumn (2013 and 2014), we found migrants tended to adjust their heights according to favourable wind profit. We found that migrants' flight altitudes correlated most closely with the altitude of maximum wind profit; however, absolute differences in flight heights and height of maximum wind profit were large. Migrants tended to fly slightly higher at inland sites compared with coastal sites during spring, but not during autumn. Migration activity was greater at coastal sites during autumn, but not during spring. This characterization of bird migration represents a critical advance in our understanding of migrant distributions in flight and a new window into habitat selection behaviours.
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Gutema, Tariku Mekonnen, Anagaw Atickem, Afework Bekele, Claudio Sillero-Zubiri, Mohammed Kasso, Diress Tsegaye, Vivek V. Venkataraman, Peter J. Fashing, Dietmar Zinner, and Nils C. Stenseth. "Competition between sympatric wolf taxa: an example involving African and Ethiopian wolves." Royal Society Open Science 5, no. 5 (May 2018): 172207. http://dx.doi.org/10.1098/rsos.172207.
Full textAbstract:
Carnivore populations are declining globally due to range contraction, persecution and prey depletion. One consequence of these patterns is increased range and niche overlap with other carnivores, and thus an elevated potential for competitive exclusion. Here, we document competition between an endangered canid, the Ethiopian wolf (EW), and the newly discovered African wolf (AW) in central Ethiopia. The diet of the ecological specialist EW was dominated by rodents, whereas the AW consumed a more diverse diet also including insects and non-rodent mammals. EWs used predominantly intact habitat, whereas AWs used mostly areas disturbed by humans and their livestock. We observed 82 encounters between the two species, of which 94% were agonistic. The outcomes of agonistic encounters followed a territory-specific dominance pattern, with EWs dominating in intact habitat and AWs in human-disturbed areas. For AWs, the likelihood of winning encounters also increased with group size. Rodent species consumed by EWs were also available in the human-disturbed areas, suggesting that these areas could be suitable habitat for EWs if AWs were not present. Increasing human encroachment not only affects the prey base of EWs, but also may impact their survival by intensifying competition with sympatric AWs.
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Kautsar, Lady Hafidaty Rahma, and Amrih Halil. "Deforestation and the Sumatera elephant roaming area in East Aceh Regency." MATEC Web of Conferences 229 (2018): 02011. http://dx.doi.org/10.1051/matecconf/201822902011.
Full textAbstract:
Reduced forest or deforestation is widespread in East Aceh Regency for plantation, agriculture and settlement purposes. Forests in Sumatra, including in East Aceh Regency are Sumatran Elephant habitat (Elephas maximus sumatranus). However, encroachment resulted in this fauna threatened sustainability, whereas Sumatran elephants are endangered species protected by law both since Dutch colonialism, post-independence, and international regulations, and Sumatran elephants have an vital ecosystem role but are seen as a nuisance to the local economy in East Aceh Regency, so it is not electrocuted, killed and abused. This paper reviews the deforestation of the Sumatran Elephant in East Aceh Regency. The results of the study show that elephant roaming areas intersect with deforestation that occurred in East Aceh Regency. As an alternative local economy, there is still the potential of ecotourism with the mascot of the Sumatran elephant. Thus the Sumatran elephant is still able to be sustainable, and the forest as habitat is maintained.
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Douglas, George W., and Michael Ryan. "Conservation Evaluation of the Seaside Birds-foot Trefoil, Lotus formosissimus, in Canada." Canadian Field-Naturalist 120, no. 2 (April 1, 2006): 153. http://dx.doi.org/10.22621/cfn.v120i2.279.
Full textAbstract:
In Canada, Seaside Birds-foot Trefoil, Lotus formosissimus, is restricted to the Victoria area on southeastern Vancouver Island and two adjacent islands. Populations at five sites are extant and have been recently inventoried, whereas populations at two or more sites in Victoria are extirpated. Existing populations represent the northern range limits of L. formosissimus. Although known populations are protected to a certain extent from direct habitat destruction, introduced herbaceous species may pose a serious threat to the continued existence of most populations and may prevent the establishment of L. formosissimus at other sites. Fire suppression, grazing, encroachment and low survivorship are also limiting factors.
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Jourdain, Camille, Nicolas Claude, Germain Antoine, Pablo Tassi, and Florian Cordier. "Influence of flood regime on riparian vegetation dynamics in rivers with alternate bars." E3S Web of Conferences 40 (2018): 02025. http://dx.doi.org/10.1051/e3sconf/20184002025.
Full textAbstract:
Throughout the 20th century, many rivers worldwide have undergone important riparian vegetation encroachment, which can be problematic in terms of flood risks and biodiversity. Nowadays, controlled floods is often considered as a management option in anthropized rivers, with the aim of limiting vegetation encroachment within river channels, as well as maintaining a diverse habitat by reactivating natural channel dynamics. In this context, this study aims at investigating the influence of different flood regimes on river bar vegetation development and dynamics, focussing on alternate bar systems which are typically found in embanked streams. This question has been addressed through two-dimensional bio-morphodynamic modeling of a simplified gravel bed river reach. Four hydrological scenarios with different flood peak discharges have been run for 50 years. For all scenarios, a steady increase in vegetation cover strongly impacts the evolution of bar morphology, until a relatively stable equilibrium is reached after one to three decades. Numerical results suggest that vegetation development on bars is associated to an increase in bar wavelength and a decrease in bar width. Higher peak flood discharges lead to narrower and longer bars, and a longer adjustment duration. When vegetation cover is fully developed, interannual flood variability seems crucial to maintain bedform and vegetation turnover.
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Howe, Alice J., José F. Rodríguez, Jennifer Spencer, Geoff R. MacFarlane, and Neil Saintilan. "Response of estuarine wetlands to reinstatement of tidal flows." Marine and Freshwater Research 61, no. 6 (2010): 702. http://dx.doi.org/10.1071/mf09171.
Full textAbstract:
The importance of estuarine wetlands to ecosystem services such as primary productivity and flood attenuation, as well as their function as habitat for threatened species has prompted efforts to restore tidal flows to degraded wetlands. We tracked the response of estuarine vegetation to tidal-flow reinstatement over 12 years (1995–2007) in a wetland of the Hunter estuary, Australia. This site provides important habitat for migratory shorebird species, which favour shallow tidal pools and saltmarsh over mangrove forest. Increased tidal flows following culvert removal reduced shorebird roost habitat by 17% because of mangrove encroachment on saltmarsh and shallow tidal pools. Saltmarsh occurred in areas with a spring tidal range <0.3 m, hydroperiod <1.0 and elevation >0.4 above the Australian height datum (mAHD), whereas mangrove occupied areas with spring tidal range >0.3 m, hydroperiod <0.45 and elevation <0.4 mAHD. By using these parameters, it is possible to exclude mangrove from saltmarsh areas and to establish saltmarsh at lower elevations in the tidal frame than would occur under natural conditions, effectively expanding saltmarsh area. These measures can be useful where landward migration of estuarine communities is restricted by infrastructure; however, they should not be considered a substitute for conservation of remnant saltmarsh or establishment of landward buffer zones.