scholarly journals Shrub Encroachment Threatens Persistence of An Endemic Insular Wetland Rodent

2021 ◽  
Author(s):  
Wesley Williams Boone ◽  
Audrey A Albrecht ◽  
Jeremy R Conrad ◽  
Chris J Lechowicz ◽  
Eric C Hellgren ◽  
...  
Keyword(s):  
Fold Increase ◽  
Shrub Encroachment ◽  
Freshwater Wetlands ◽  
Shrub Cover ◽  
Mammal Species ◽  
Negatively Associated ◽  
Aquatic Mammal ◽  
Wildlife Species ◽  
Extinction Rates ◽  
Oryzomys Palustris

Abstract Shrub encroachment is altering the structure and species composition of freshwater wetlands across the globe. These changes are likely to be particularly detrimental for threatened wetland vertebrates. However, little research has focused on how shrub encroachment influences threatened wetland vertebrates. We sought to determine how vegetative structure and shrub cover influenced the occurrence of a threatened semi-aquatic mammal species, the Sanibel Island rice rat (Oryzomys palustris sanibeli). Using aerial photography from across the Sanibel Island rice rat’s range, we found a 5.5-fold increase in shrub cover over a 71-year period. To link these changes to the current distribution of the species, we evaluated the influence of vegetation and metrics of inundation on probability of occurrence and localized colonization and extinction rates over a three-year period. We found Sanibel Island rice rats on 18 (33.3%) of our 54 sites. Their occurrence was positively associated with elevated sand cordgrass (Spartina bakeri) cover and increased elevation, but negatively associated with elevated shrub cover. Their probability of colonization was negatively associated with increased shrub cover. Extinction probabilities for Sanibel Island rice rats were positively associated with increased rainfall totals in the preceding three months and increased shrub cover. Increases in shrub cover reduce sand cordgrass cover, which additively may be driving the decline of this once ubiquitous species. We conclude that shrub encroachment of freshwater wetlands requires greater attention due to its potential to imperil wetland endemic wildlife species.

scholarly journals Predicting extinction of mammals in the Brazilian Amazon

Oryx ◽  
2005 ◽  
Vol 39 (3) ◽  
pp. 347-350 ◽  
Author(s):  
Carlos Eduardo Viveiros Grelle
Keyword(s):  
Functional Groups ◽  
Threatened Species ◽  
Fold Increase ◽  
Brazilian Amazon ◽  
Ecosystem Stability ◽  
Infrastructure Projects ◽  
Mammal Species ◽  
Extinction Rates ◽  
Cascade Effect ◽  
Species Area

Using the species-area correlation I predicted the percentage of endemic Amazonian mammals committed to extinction by 2020 as an outcome of deforestation resulting from the implementation of mega-infrastructure projects in the Brazilian Amazon. Simulations based on optimistic and non-optimistic deforestation scenarios showed a 2-fold and a 3-fold increase, respectively, in Amazonian mammals committed to extinction. The predicted number of threatened species by 2020 was 5–18% of the total number of endemic mammal species, depending on the scenario and equation used. This increase in extinction rates could be catastrophic for ecosystem stability in the Amazon because the loss of functional groups may produce a cascade effect of species extinctions.

Shrub encroachment is not always land degradation: Insights from ground-dwelling beetle species niches along a shrub cover gradient in a semi-arid Namibian savanna

2018 ◽  
Vol 30 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Robert Hering ◽  
Morgan Hauptfleisch ◽  
Katja Geißler ◽  
Arnim Marquart ◽  
Maria Schoenen ◽  
...  
Keyword(s):  
Land Degradation ◽  
Shrub Encroachment ◽  
Beetle Species ◽  
Shrub Cover ◽  
Semi Arid

scholarly journals Habitat associations of the marsh rice rat (Oryzomys palustris) in freshwater wetlands of southern Illinois

2011 ◽  
Vol 92 (3) ◽  
pp. 552-560 ◽  
Author(s):  
Bryan W. Eubanks ◽  
Eric C. Hellgren ◽  
Jack R. Nawrot ◽  
Robert D. Bluett
Keyword(s):  
Habitat Associations ◽  
Freshwater Wetlands ◽  
Southern Illinois ◽  
Marsh Rice Rat ◽  
Oryzomys Palustris

scholarly journals How many bird and mammal extinctions has recent conservation action prevented?

2020 ◽  
Author(s):  
Friederike C. Bolam ◽  
Louise Mair ◽  
Marco Angelico ◽  
Thomas M. Brooks ◽  
Mark Burgman ◽  
...  
Keyword(s):  
Threatened Species ◽  
Biological Diversity ◽  
Expert Elicitation ◽  
Convention On Biological Diversity ◽  
Elicitation Method ◽  
Conservation Action ◽  
Mammal Species ◽  
Extinction Rates ◽  
Near Future

AbstractAichi Target 12 of the Convention on Biological Diversity (CBD) aims to ‘prevent extinctions of known threatened species’. To measure its success, we used a Delphi expert elicitation method to estimate the number of bird and mammal species whose extinctions were prevented by conservation action in 1993 - 2020 (the lifetime of the CBD) and 2010 - 2020 (the timing of Aichi Target 12). We found that conservation prevented 21–32 bird and 7–16 mammal extinctions since 1993, and 9–18 bird and 2–7 mammal extinctions since 2010. Many remain highly threatened, and may still become extinct in the near future. Nonetheless, given that ten bird and five mammal species did go extinct (or are strongly suspected to) since 1993, extinction rates would have been 2.9–4.2 times greater without conservation action. While policy commitments have fostered significant conservation achievements, future biodiversity action needs to be scaled up to avert additional extinctions.

scholarly journals Soil nitrogen response to shrub encroachment in a degrading semiarid grassland

2018 ◽  
Author(s):  
Thomas Turpin-Jelfs ◽  
Katerina Michaelides ◽  
Joel A. Biederman ◽  
Alexandre M. Anesio
Keyword(s):  
Nitrogen Fixation ◽  
Soil Nitrogen ◽  
Biological Nitrogen Fixation ◽  
Inorganic Nitrogen ◽  
Shrub Encroachment ◽  
Shrub Cover ◽  
Prosopis Velutina ◽  
Free Living ◽  
Semiarid Grassland ◽  
Biological Nitrogen

Abstract. Transitions from grass- to shrub-dominated states in drylands by woody plant encroachment represent significant forms of land cover change with the potential to alter the spatial distribution and cycling of soil resources. Yet an understanding of how this phenomenon impacts the soil nitrogen pool, which is essential to primary production in arid and semiarid systems, is poorly resolved. In this study, we quantified how the distribution and speciation of soil nitrogen, as well as rates of free-living biological nitrogen fixation, changed along a gradient of increasing mesquite (Prosopis velutina Woot.) cover in a semiarid grassland of the Southwestern US. Our results show that site-level concentrations of total nitrogen remain unchanged with increasing shrub cover as losses from intershrub areas (sum of grass and bare-soil cover) are proportional to increases in soils under shrub canopies. However, despite the similar carbon-to-nitrogen ratio and microbial biomass of soil from intershrub and shrub areas at each site, site-level concentrations of inorganic nitrogen increase with shrub cover due to the accumulation of ammonium and nitrate in soils beneath shrub canopies. Using the acetylene reduction assay technique, we found increasing ratios of inorganic nitrogen-to-bioavailable phosphorus inhibit rates of biological nitrogen fixation by free-living soil bacteria. Consequently, we conclude that shrub encroachment has the potential to significantly alter the dynamics of soil nitrogen cycling in dryland systems.

scholarly journals Is captive breeding a priority for manatee conservation in Mexico?

Oryx ◽  
2018 ◽  
Vol 54 (1) ◽  
pp. 110-117 ◽  
Author(s):  
Alejandro Ortega-Argueta ◽  
Delma Nataly Castelblanco-Martínez
Keyword(s):  
Captive Breeding ◽  
Integrated Management ◽  
Coastal Development ◽  
Conservation Strategies ◽  
Caribbean Region ◽  
Mammal Species ◽  
Aquatic Mammal ◽  
Policy And Strategy ◽  
In Captivity ◽  
The Impact

AbstractThe Endangered Antillean manateeTrichechus manatus manatusis one of the most threatened aquatic mammal species in Mexico and the wider Caribbean region. The decline of this subspecies is mainly a result of historical exploitation and the impact of current coastal development. The conservation strategies adopted for the Antillean manatee include habitat protection, reduction of the most severe threats, and the rescue of stranded, orphaned or injured individuals and their management in captivity. This latter strategy has produced positive outcomes in some countries but has been the subject of controversy in others, including Mexico. We analyse the benefits and challenges associated with the management of captive manatees in Mexico, and the consequences of a lack of government policy and strategy for the post-rehabilitation release of individuals. We describe the evolution of this controversy from 1997–2017 in Mexico, analyse the consequences and implications for the conservation of the species, and propose an integrated management strategy that could address the issues raised. Although this strategy has been developed in the context of Mexico, it is applicable to management of this species across the Caribbean region.

scholarly journals Wildlife assessment of the Chandragiri hills, Kathmandu: Potentiality for ecotourism

2020 ◽  
Vol 6 (1) ◽  
pp. 27-50
Author(s):  
Hem Bahadur Katuwal ◽  
Hari Basent ◽  
Hari Prasad Sharma ◽  
Sabina Koirala ◽  
Bhaiya Khanal ◽  
...  
Keyword(s):  
Hot Spot ◽  
Bird Species ◽  
Habitat Associations ◽  
Wildlife Habitat ◽  
Butterfly Species ◽  
Mammal Species ◽  
Ecological Information ◽  
Wildlife Species ◽  
Crucial Information ◽  
Management Policies

Wildlife assessments can provide crucial information regarding species richness, relative abundance and spatial, temporal, and ecological information on wildlife habitat associations. The assessment’s information can in turn be used for developing management policies including for establishing touristic zones. We investigated wildlife occurrences in the Chandragiri Hills, Kathmandu Nepal from 2015-2019 to provide baseline data to inform the potential sites for ecotourism. During the study period, we recorded 30 mammal species, 199 bird species, 34 herpetofauna species and 77 butterfly species. The area harbors three globally and six nationally threatened mammal species, two globally and seven nationally threatened with one endemic bird species, one globally and nationally threatened herpetofauna, and one nationally threatened butterfly species. We also explored four potential hiking routes for observing wildlife and providing scenic views of the Himalayan range and Kathmandu city. Therefore, we expect Chandragiri Hills can become one of the hot spot for tourists to observe both common and threatened wildlife species in Nepal.

scholarly journals Dominant shrub species are a strong predictor of plant species diversity along subalpine pasture-shrub transects

Alpine Botany ◽  
2020 ◽  
Vol 130 (2) ◽  
pp. 141-156
Author(s):  
Tobias Zehnder ◽  
Andreas Lüscher ◽  
Carmen Ritzmann ◽  
Caren M. Pauler ◽  
Joel Berard ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Plant Diversity ◽  
Beta Diversity ◽  
Spatial Scales ◽  
Strong Predictor ◽  
Shrub Encroachment ◽  
Swiss Alps ◽  
Shrub Cover ◽  
Shrub Species

Abstract Abandonment of pastures and successional shrub expansion are widespread in European mountain regions. Moderate shrub encroachment is perceived beneficial for plant diversity by adding new species without outcompeting existing ones, yet systematic evidence is missing. We surveyed vegetation along 24 transects from open pasture into shrubland across the Swiss Alps using a new protocol distinguishing different spatial scales, shrub cover of each plot (2 × 2 m) and larger-scale zonal cover along the transect. Data were analysed using generalized linear models of shrub cover, shrub species and environmental conditions, such as geology, aspect or soil. Most shrub communities were dominated by Alnus viridis (62% of transects) and Pinus mugo (25%), and the rest by other shrub species (13%). These dominant shrub species explained vegetation response to shrub cover well, without need of environmental variables in the model. Compared to open pasture, A. viridis resulted in an immediate linear decline in plant species richness and a marginal increase in beta-diversity (maximally + 10% at 35% cover). Dense A. viridis hosted 62% less species than open pasture. In P. mugo, species richness remained stable until 40% shrub cover and dropped thereafter; beta-diversity peaked at 35% cover. Hence, scattered P. mugo increases beta-diversity without impairing species richness. In transects dominated by other shrubs, species richness and beta-diversity peaked at 40–60% shrub cover (+ 23% both). A. viridis reduced species richness in a larger area around the shrubs than P. mugo. Therefore, effects of shrub encroachment on plant diversity cannot be generalized and depend on dominant shrub species.

Preserving Australian native fauna: zoo-based breeding programs as part of a more unified strategic approach

2013 ◽  
Vol 61 (1) ◽  
pp. 101 ◽  
Author(s):  
Carolyn J. Hogg
Keyword(s):  
Captive Breeding ◽  
Early Stage ◽  
Strategy Development ◽  
Mammal Species ◽  
Breeding Programs ◽  
Initial Development ◽  
Good Communication ◽  
Critically Endangered Species ◽  
Extinction Rates ◽  
Epbc Act

High extinction rates and loss of biodiversity is a critical conservation matter. Twenty-two Australian mammal species have become extinct in the last 200 years. Of the 95 mammal species under the EPBC Act, 51 have recovery plans and 15 of these have captive components. Zoo-based programs as part of a recovery plan can ‘buy’ time for critically endangered species. In Australia, programs are established as a result of government recovery plans, though more consultation with the zoo industry in initial development phase is needed. Often by the time the decision is taken to remove individuals from the wild for captive breeding, the source populations are fragmented and small. As zoo-based programs become more successful, issues with space limitations arise. This may be rectified with regular release of individuals or avoidance of maintaining post-reproductive and/or non-reproductive animals long-term. Those involved in recovery efforts should make few assumptions on the captive productivity of species, unless the species has been held before. Success of the captive component of a recovery program can be measured by the number of animals bred for release and the level of genetic diversity retained by the program. Although recovery teams are responsible for strategy development, good communication between parties from an early stage is essential. Where a captive component is needed, a more unified strategy, developed early, should provide our native fauna with a realistic chance of recovery. Zoo-based breeding programs are useful in assisting with the preservation of some Australian fauna, whilst for others they will have limited relevance.

scholarly journals Identification of the Optimal Season and Spectral Regions for Shrub Cover Estimation in Grasslands

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3098
Author(s):  
Irini Soubry ◽  
Xulin Guo
Keyword(s):  
Remote Sensing ◽  
Ecosystem Health ◽  
Woody Species ◽  
Shrub Encroachment ◽  
Shrub Cover ◽  
Grassland Ecosystem ◽  
Good Separation ◽  
Spectral Separability ◽  
Late Stages ◽  
Trees And Shrubs

Woody plant encroachment (WPE), the expansion of native and non-native trees and shrubs into grasslands, is a less studied factor that leads to declines in grassland ecosystem health. With the increasing application of remote sensing in grassland monitoring and measuring, it is still difficult to detect WPE at its early stages when its spectral signals are not strong enough. Even at late stages, woody species have strong vegetation characteristics that are commonly categorized as healthy ecosystems. We focus on how shrub encroachment can be detected through remote sensing by looking at the biophysical and spectral properties of the WPE grassland ecosystem, investigating the appropriate season and wavelengths that identify shrub cover, testing the spectral separability of different shrub cover groups and by revealing the lowest shrub cover that can be detected by remote sensing. Biophysical results indicate spring as the best season to distinguish shrubs in our study area. The earliest shrub encroachment can be identified most likely only when the cover reaches between 10% and 25%. A correlation between wavelength spectra and shrub cover indicated four regions that are statistically significant, which differ by season. Furthermore, spectral separability of shrubs increases with their cover; however, good separation is only possible for pure shrub pixels. From the five separability metrics used, Transformed divergence and Jeffries-Matusita distance have better interpretations. The spectral regions for pure shrub pixel separation are slightly different from those derived by correlation and can be explained by the influences from land cover mixtures along our study transect.

Sign in / Sign up

Export Citation Format

Share Document