1
|
Maicher V, Delabye S, Murkwe M, Doležal J, Altman J, Kobe IN, Desmist J, Fokam EB, Pyrcz T, Tropek R. Effects of disturbances by forest elephants on diversity of trees and insects in tropical rainforests on Mount Cameroon. Sci Rep 2020; 10:21618. [PMID: 33303812 PMCID: PMC7729851 DOI: 10.1038/s41598-020-78659-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/24/2020] [Indexed: 11/20/2022] Open
Abstract
Natural disturbances are essential for tropical forests biodiversity. In the Afrotropics, megaherbivores have played a key role before their recent decline. Contrastingly to savanna elephants, forest elephants’ impact on ecosystems remains poorly studied. Few decades ago, forests on Mount Cameroon were divided by lava flows, not being crossed by a local population of forest elephants until now. We assessed communities of trees, butterflies and two guilds of moths in the disturbed and undisturbed forests split by the longest lava flow. We surveyed 32 plots, recording 2025 trees of 97 species, and 7853 insects of 437 species. The disturbed forests differed in reduced tree density, height, and high canopy cover, and in increased DBH. Forest elephants’ selective browsing and foraging also decreased tree species richness and altered their composition. The elephant disturbance increased butterfly species richness and had various effects on species richness and composition of the insect groups. These changes were likely caused by disturbance-driven alterations of habitats and species composition of trees. Moreover, the abandonment of forests by elephants led to local declines of range-restricted butterflies. The recent declines of forest elephants across the Afrotropics probably caused similar changes in forest biodiversity and should be reflected by conservation actions.
Collapse
Affiliation(s)
- Vincent Maicher
- Institute of Entomology, Biology Centre, Czech Academy of Sciences, Branisovska 31, 37005, Ceske Budejovice, Czech Republic. .,Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic. .,Nicholas School of the Environment, Duke University, 9 Circuit Dr., Durham, NC, 27710, USA.
| | - Sylvain Delabye
- Institute of Entomology, Biology Centre, Czech Academy of Sciences, Branisovska 31, 37005, Ceske Budejovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic
| | - Mercy Murkwe
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.,Department of Ecology, Faculty of Science, Charles University, Vinicna 7, 12844, Prague, Czech Republic
| | - Jiří Doležal
- Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic.,Institute of Botany, Czech Academy of Sciences, Dukelska 135, 37982, Trebon, Czech Republic
| | - Jan Altman
- Institute of Botany, Czech Academy of Sciences, Dukelska 135, 37982, Trebon, Czech Republic
| | - Ishmeal N Kobe
- Department of Ecology, Faculty of Science, Charles University, Vinicna 7, 12844, Prague, Czech Republic
| | - Julie Desmist
- Institute of Entomology, Biology Centre, Czech Academy of Sciences, Branisovska 31, 37005, Ceske Budejovice, Czech Republic.,University Paris-Saclay, 15 rue Georges Clemenceau, 91400, Orsay, France
| | - Eric B Fokam
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Tomasz Pyrcz
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30387, Krakow, Poland.,Nature Education Centre of the Jagiellonian University, Gronostajowa 5, 30387, Krakow, Poland
| | - Robert Tropek
- Institute of Entomology, Biology Centre, Czech Academy of Sciences, Branisovska 31, 37005, Ceske Budejovice, Czech Republic. .,Department of Ecology, Faculty of Science, Charles University, Vinicna 7, 12844, Prague, Czech Republic.
| |
Collapse
|
2
|
Ungulate herbivores reduce fruit production of shrubs in dry conifer forests of the interior Pacific Northwest, USA. FOOD WEBS 2020. [DOI: 10.1016/j.fooweb.2020.e00172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
3
|
Gaget E, Parr CL, Sirami C. Effects of fire frequency on savanna butterfly diversity and composition: A preliminary study. KOEDOE: AFRICAN PROTECTED AREA CONSERVATION AND SCIENCE 2020. [DOI: 10.4102/koedoe.v62i1.1617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Fire plays a major role in many biomes, is widely used as a management tool and is likely to be affected by climate change. For effective conservation management, it is essential to understand how fire regimes affect different taxa, yet responses of invertebrates are particularly poorly documented. We tested how different fire frequencies influence savanna butterfly diversity and composition by using a long-term savanna fire experiment initiated in 1954 in the Kruger National Park (South Africa). We compared butterfly abundance, species richness and community composition across three fire frequencies: high (burnt annually), medium (burnt triennially) and low (burnt twice in 60 years). Plots with high fire frequency hosted higher abundance than medium- or low-frequency plots. Fire frequencies did not affect species richness, but they led to distinct communities of butterflies. Our findings suggest that, in view of the three fire frequencies tested, a spatial diversity of fire frequencies may increase butterfly diversity at the landscape level in wet savannas. Managers may need to promote a greater diversity of fire frequencies by increasing fire frequency in some areas to provide habitat for species requiring high fire frequency, and by decreasing fire frequency in a large proportion of the landscape to provide fire refuges. This study provides new insights for butterfly conservation in savannas and highlights several knowledge gaps, which further studies should address for insect responses to be given adequate consideration in fire management strategies.Conservation implications: A spatial diversity of fire frequencies may increase butterfly diversity. Managers may need to promote a greater diversity of fire frequencies by increasing fire frequency in some areas to provide habitat for species requiring high fire frequency, and by decreasing fire frequency in other areas to provide fire refuges.
Collapse
|
4
|
Begosh A, Smith LM, McMurry ST, Harris JP. Influence of the Conservation Reserve Program (CRP) and playa wetlands on pollinator communities in the Southern High Plains, USA. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 256:109910. [PMID: 31818736 DOI: 10.1016/j.jenvman.2019.109910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/19/2019] [Accepted: 11/19/2019] [Indexed: 06/10/2023]
Abstract
Numerous studies have documented that invertebrate pollinator services are critical to the world economy. Factors including habitat loss and agricultural practices, however, threaten pollinator populations. Many counties in the Southern High Plains were identified as at risk for a shortage of pollination service from wild bees. This region also has one of the highest concentrations of Conservation Reserve Program (CRP) contracts in the US. The CRP is the largest, voluntary, private lands conservation program in the US and was targeted as a program to improve pollinator habitat. Our objective was to determine how the predominant land uses in the SHP (native grassland, CRP, and cropland) affect pollinator abundance and species richness, and more specifically if the CRP can provide quality habitat for pollinators. We also examined how the keystone habitat, playa wetlands, embedded within these land uses contribute to pollinator habitat (land type: uplands vs. wetland). We used blue vane traps placed in playa basins and adjacent uplands to determine Hymenoptera abundance and richness from April to October in 2013 and 2014. The CRP had lower abundance than cropland and native grassland, and generally less richness. Uplands and playa wetlands had little difference in Hymenoptera abundance and richness. Patch size negatively influenced abundance but had a positive influence on richness. The interaction of vegetation height and percent bare ground positively influenced abundance in cropland and native grasslands, and positively influenced richness in all land uses. In the CRP, vegetation height negatively influenced Hymenoptera abundance and percent bare ground had a positive influence. The years sampled in this study were during a severe extended drought; therefore, these results may be reflective of poor floral resources. The CRP has potential to create valuable habitat for pollinators if land managers incorporate a diversity of native grasses and native forbs into plantings to enhance pollinator foraging and nesting habitat.
Collapse
Affiliation(s)
- Angela Begosh
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK, 74078, USA.
| | - Loren M Smith
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK, 74078, USA.
| | - Scott T McMurry
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK, 74078, USA.
| | - Jonathan P Harris
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK, 74078, USA.
| |
Collapse
|
5
|
Tyrrell P, Toit JT, Macdonald DW. Conservation beyond protected areas: Using vertebrate species ranges and biodiversity importance scores to inform policy for an east African country in transition. CONSERVATION SCIENCE AND PRACTICE 2019. [DOI: 10.1111/csp2.136] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Peter Tyrrell
- Wildlife Conservation Research Unit, Department of ZoologyUniversity of Oxford, Recanati‐Kaplan Centre, Tubney House Abingdon UK
- South Rift Association of Landowners Nairobi Kenya
- Department of Geography and Environmental StudiesUniversity of Nairobi Nairobi Kenya
| | - Johan T. Toit
- Department of Wildland ResourcesUtah State University Logan Utah
| | - David W. Macdonald
- Wildlife Conservation Research Unit, Department of ZoologyUniversity of Oxford, Recanati‐Kaplan Centre, Tubney House Abingdon UK
| |
Collapse
|
6
|
Pan D, Li X, De K, Wang L, Wang D, Guo Q, Gao C, Zhong Z, Zhu H, Shen Z, Seastedt TR. Food and habitat provisions jointly determine competitive and facilitative interactions among distantly related herbivores. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13456] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Duofeng Pan
- Key Laboratory of Vegetation Ecology of Ministry of Education Institute of Grassland Science School of Environment Northeast Normal University Changchun China
- Institute of Forage and Grassland Sciences Heilongjiang Academy of Agricultural Sciences Harbin China
| | - Xincheng Li
- Key Laboratory of Vegetation Ecology of Ministry of Education Institute of Grassland Science School of Environment Northeast Normal University Changchun China
| | - Kejia De
- Qinghai Academy of Animal Science and Veterinary Medicine Qinghai University Xining China
| | - Ling Wang
- Key Laboratory of Vegetation Ecology of Ministry of Education Institute of Grassland Science School of Environment Northeast Normal University Changchun China
| | - Deli Wang
- Key Laboratory of Vegetation Ecology of Ministry of Education Institute of Grassland Science School of Environment Northeast Normal University Changchun China
| | - Qinfeng Guo
- Eastern Forest Environmental Threat Assessment Center US Department of Agriculture Forest ServiceResearch Triangle Park NC USA
| | - Chao Gao
- Institute of Forage and Grassland Sciences Heilongjiang Academy of Agricultural Sciences Harbin China
| | - Zhiwei Zhong
- Key Laboratory of Vegetation Ecology of Ministry of Education Institute of Grassland Science School of Environment Northeast Normal University Changchun China
| | - Hui Zhu
- Key Laboratory of Vegetation Ecology of Ministry of Education Institute of Grassland Science School of Environment Northeast Normal University Changchun China
| | - Zhongbao Shen
- Institute of Forage and Grassland Sciences Heilongjiang Academy of Agricultural Sciences Harbin China
| | - Timothy R. Seastedt
- Department of Ecology and Evolutionary Biology Institute of Arctic and Alpine Research University of Colorado Boulder CO USA
| |
Collapse
|
7
|
Forbes ES, Cushman JH, Burkepile DE, Young TP, Klope M, Young HS. Synthesizing the effects of large, wild herbivore exclusion on ecosystem function. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13376] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elizabeth S. Forbes
- Department of Ecology, Evolution, and Marine Biology University of California, Santa Barbara Santa Barbara California
| | - J. Hall Cushman
- Department of Natural Resources and Environmental Science University of Nevada – Reno Reno Nevada
| | - Deron E. Burkepile
- Department of Ecology, Evolution, and Marine Biology University of California, Santa Barbara Santa Barbara California
| | - Truman P. Young
- Department of Plant Sciences University of California, Davis Davis California
| | - Maggie Klope
- Department of Ecology, Evolution, and Marine Biology University of California, Santa Barbara Santa Barbara California
| | - Hillary S. Young
- Department of Ecology, Evolution, and Marine Biology University of California, Santa Barbara Santa Barbara California
| |
Collapse
|
8
|
Large mammals generate both top-down effects and extended trophic cascades on floral-visitor assemblages. JOURNAL OF TROPICAL ECOLOGY 2019. [DOI: 10.1017/s0266467419000142] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractCascading effects of high trophic levels onto lower trophic levels have been documented in many ecosystems. Some studies also show evidence of extended trophic cascades, in which guilds dependent on lower trophic levels, but uninvolved in the trophic cascade themselves, are affected by the trophic cascade due to their dependence on lower trophic levels. Top-down effects of large mammals on plants could lead to a variety of extended trophic cascades on the many guilds dependent on plants, such as pollinators. In this study, floral-visitor and floral abundances and assemblages were quantified within a series of 1-ha manipulations of large-mammalian herbivore density in an African savanna. Top-down effects of large mammals on the composition of flowers available for floral visitors are first shown, using regressions of herbivore activity on metrics of floral and floral-visitor assemblages. An extended trophic cascade is also shown: the floral assemblage further altered the assemblage of floral visitors, according to a variety of approaches, including a structural equation modelling approach (model with an extended trophic cascade was supported over a model without, AICc weight = 0.984). Our study provides support for extended trophic cascades affecting floral visitors, suggesting that trophic cascades can have impacts throughout entire communities.
Collapse
|
9
|
Ellis TD, Cushman JH. Indirect effects of a large mammalian herbivore on small mammal populations: Context-dependent variation across habitat types, mammal species, and seasons. Ecol Evol 2018; 8:12115-12125. [PMID: 30598804 PMCID: PMC6303759 DOI: 10.1002/ece3.4670] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 09/12/2018] [Accepted: 09/13/2018] [Indexed: 11/28/2022] Open
Abstract
Multiple consumer species frequently co-occur in the same landscape and, through effects on surrounding environments, can interact in direct and indirect ways. These interactions can vary in occurrence and importance, and focusing on this variation is critical for understanding the dynamics of interactions among consumers. Large mammalian herbivores are important engineers of ecosystems worldwide, have substantial impacts on vegetation, and can indirectly affect small-mammal populations. However, the degree to which such indirect effects vary within the same system has received minimal attention. We used a 16-year-old exclosure experiment, stratified across a heterogeneous landscape, to evaluate the importance of context-dependent interactions between tule elk (Cervus canadensis nannodes) and small mammals (deer mice [Peromyscus maniculatus], meadow voles [Microtus californicus], and harvest mice [Reithrodontymys megalotis]) in a coastal grassland in California. Effects of elk on voles varied among habitats and seasons: In open grasslands, elk reduced vole numbers during fall 2013 but not summer 2014; in Lupinus-dominated grasslands, elk reduced vole numbers during summer 2014 but not fall 2013; and in Baccharis-dominated grasslands, elk had no effect on vole numbers in either season. Effects of elk on the two mice species also varied among habitats and seasons, but often in different ways from voles and each other. In fall 2013, elk decreased mice abundances in Lupinus-dominated grasslands, but not in Baccharis-dominated or open grasslands. In summer 2014, elk decreased the abundance of harvest mice consistently across habitat types. In contrast, elk increased deer-mice numbers in open grasslands but not other habitats. Within the same heterogenous study system, the influence of elk on small mammals was strongly context-dependent, varying among habitats, mammal species, and seasons. We hypothesize that such variability is common in nature and that failure to consider it may yield inaccurate findings and limit our understanding of interactions among co-occurring consumers.
Collapse
Affiliation(s)
- Taylor D. Ellis
- Department of BiologySonoma State UniversityRohnert ParkCalifornia
- Present address:
Point Reyes National SeashoreCalifornia
| | - J. Hall Cushman
- Department of Natural Resources and Environmental ScienceUniversity of NevadaRenoNevada
| |
Collapse
|
10
|
Mekuria W, Wondie M, Amare T, Wubet A, Feyisa T, Yitaferu B. Restoration of degraded landscapes for ecosystem services in North-Western Ethiopia. Heliyon 2018; 4:e00764. [PMID: 30186984 PMCID: PMC6121161 DOI: 10.1016/j.heliyon.2018.e00764] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 07/09/2018] [Accepted: 08/24/2018] [Indexed: 11/17/2022] Open
Abstract
Establishing exclosures has become common in Ethiopia, especially in the central and northern highlands, where they serve as a response to persistent forest degradation, affecting forest resources and ecosystem services. We investigated changes in vegetation composition, aboveground biomass and soil properties after establishing an exclosure on degraded communal grazing land in Aba-Gerima watershed, North-Western Ethiopia. We selected 4-yr-old exclosure and paired the selected exclosure with an adjacent communal grazing land. In the exclosure, we recorded 46 plant species representing 32 families, whereas we recorded 18 plant species representing 13 families in the adjacent communal grazing lands. Most of the identified woody species are economically important. We observed significant differences between the exclosure and adjacent grazing land in woody species richness, diversity and evenness. Exclosure displayed higher woody species density, basal area and aboveground woody biomass compared to the adjacent grazing land. Landscape position influenced vegetation composition, richness and diversity in the exclosure and adjacent grazing land. Significant differences between the exclosure and adjacent grazing land in soil properties were detected. The influence of landscape positions on soil properties was not consistent. At foot slope position, in the 0- to 15-cm and 15- to 30-cm depths, soil organic carbon and nitrogen content detected in exclosure were significantly higher when compared to the values observed in the adjacent grazing land. However, differences at mid and upper slope positions were not significant. The results support that the establishment of exclosures on degraded lands could support the restoration of degraded native vegetation and soil properties, which consequently enhance the ecosystem services that can be obtained from degraded lands.
Collapse
Affiliation(s)
- Wolde Mekuria
- International Water Management Institute, Addis Ababa, Ethiopia
| | - Menale Wondie
- Amhara Regional Agricultural Research Institute, Bahir-Dar, Ethiopia
| | - Tadele Amare
- Amhara Regional Agricultural Research Institute, Bahir-Dar, Ethiopia
| | - Asmare Wubet
- Amhara Regional Agricultural Research Institute, Bahir-Dar, Ethiopia
| | - Tesfaye Feyisa
- Amhara Regional Agricultural Research Institute, Bahir-Dar, Ethiopia
| | - Birru Yitaferu
- Amhara Regional Agricultural Research Institute, Bahir-Dar, Ethiopia
| |
Collapse
|
11
|
Moe SR, Eldegard K, Rannestad OT, Okullo P, Lindtjørn O, Støen OG, Dale S. Strong positive effects of termites on savanna bird abundance and diversity are amplified by large herbivore exclusion. Ecol Evol 2017; 7:10079-10088. [PMID: 29238538 PMCID: PMC5723628 DOI: 10.1002/ece3.3513] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/26/2017] [Accepted: 09/13/2017] [Indexed: 11/17/2022] Open
Abstract
Vast areas of the African savanna landscapes are characterized by tree‐covered Macrotermes termite mounds embedded within a relatively open savanna matrix. In concert with termites, large herbivores are important determinants of savanna woody vegetation cover. The relative cover of woody species has considerable effects on savanna function. Despite the potentially important ecological relationships between termite mounds, woody plants, large herbivores, and birds, these associations have previously received surprisingly little attention. We experimentally studied the effects of termites and large herbivores on the avian community in Lake Mburo National Park, Uganda, where woody vegetation is essentially limited to termite mounds. Our experiment comprised of four treatments in nine replicates; unfenced termite mounds, fenced mounds (excluding large mammals), unfenced adjacent savanna, and fenced savanna. We recorded species identity, abundance, and behavior of all birds observed on these plots over a two‐month period, from late dry until wet season. Birds used termite mounds almost exclusively, with only 3.5% of observations occurring in the treeless intermound savanna matrix. Mean abundance and species richness of birds doubled on fenced (large herbivores excluded) compared to unfenced mounds. Feeding behavior increased when large mammals were excluded from mounds, both in absolute number of observed individuals, and relative to other behaviors. This study documents the fundamental positive impact of Macrotermes termites on bird abundance and diversity in an African savanna. Birds play crucial functional roles in savanna ecosystems, for example, by dispersing fruits or regulating herbivorous insect populations. Thus, the role of birds in savanna dynamics depends on the distribution and abundance of termite mounds.
Collapse
Affiliation(s)
- Stein R Moe
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003, NO-1432 Ås Norway
| | - Katrine Eldegard
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003, NO-1432 Ås Norway
| | - Ole Tobias Rannestad
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003, NO-1432 Ås Norway
| | - Paul Okullo
- Nabuin Zonal Agricultural Research and Development Institute National Agricultural Research Organisation Moroto Uganda
| | - Ommund Lindtjørn
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003, NO-1432 Ås Norway
| | - Ole Gunnar Støen
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003, NO-1432 Ås Norway
| | - Svein Dale
- Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003, NO-1432 Ås Norway
| |
Collapse
|
12
|
Pryke JS, Roets F, Samways MJ. Wild Herbivore Grazing Enhances Insect Diversity over Livestock Grazing in an African Grassland System. PLoS One 2016; 11:e0164198. [PMID: 27783685 PMCID: PMC5082622 DOI: 10.1371/journal.pone.0164198] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 09/21/2016] [Indexed: 11/18/2022] Open
Abstract
Southern Africa's grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural grazing dynamics, which could have an impact on the long-term value of ENs for insects. Here we compared dung beetle, butterfly and grasshopper diversity in ENs across a landscape mosaic of timber plantations, where 1) wild megaherbivores were maintained, 2) in ENs where these herbivores were replaced by livestock and, 3) in a nearby World Heritage PA which retained its natural complement of megaherbivores. Sites in the PA far from any plantation were similar in composition to those in the wild grazed EN. Presence of the wild grazers improved the alpha- and beta-diversity of all focal insect taxa when compared to domestic grazing. Furthermore, species composition shows significant differences between the two grazing systems indicating that an assemblage of native large mammals facilitates insect diversity conservation. We support the maintenance or introduction of large native mammals in ENs or similar conservation areas in production landscapes to simulate the ecological conditions and natural heterogeneity in nearby PAs.
Collapse
Affiliation(s)
- James S. Pryke
- Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
- * E-mail:
| | - Francois Roets
- Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Michael J. Samways
- Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| |
Collapse
|
13
|
Veblen KE, Nehring KC, McGlone CM, Ritchie ME. Contrasting effects of different mammalian herbivores on sagebrush plant communities. PLoS One 2015; 10:e0118016. [PMID: 25671428 PMCID: PMC4324772 DOI: 10.1371/journal.pone.0118016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 01/07/2015] [Indexed: 11/28/2022] Open
Abstract
Herbivory by both grazing and browsing ungulates shapes the structure and functioning of terrestrial ecosystems worldwide, and both types of herbivory have been implicated in major ecosystem state changes. Despite the ecological consequences of differences in diets and feeding habits among herbivores, studies that experimentally distinguish effects of grazing from spatially co-occurring, but temporally segregated browsing are extremely rare. Here we use a set of long-term exclosures in northern Utah, USA, to determine how domestic grazers vs. wild ungulate herbivores (including browsers and mixed feeders) affect sagebrush-dominated plant communities that historically covered ~62 million ha in North America. We sampled plant community properties and found that after 22 years grazing and browsing elicited perceptible changes in overall plant community composition and distinct responses by individual plant species. In the woody layer of the plant community, release from winter and spring wild ungulate herbivory increased densities of larger Wyoming big sagebrush (Artemisia tridentata, ssp. wyomingensis) at the expense of small sagebrush, while disturbance associated with either cattle or wild ungulate activity alone was sufficient to increase bare ground and reduce cover of biological soil crusts. The perennial bunchgrass, bottlebrush squirretail (Elymus elymoides), responded positively to release from summer cattle grazing, and in turn appeared to competitively suppress another more grazing tolerant perennial grass, Sandberg's blue grass (Poa secunda). Grazing by domestic cattle also was associated with increased non-native species biomass. Together, these results illustrate that ungulate herbivory has not caused sagebrush plant communities to undergo dramatic state shifts; however clear, herbivore-driven shifts are evident. In a dry, perennial-dominated system where plant community changes can occur very slowly, our results provide insights into potential long-term trajectories of these plant communities under different large herbivore regimes. Our results can be used to guide long-term management strategies for sagebrush systems and improve habitat for endemic wildlife species such as sage-grouse (Centrocercus spp.).
Collapse
Affiliation(s)
- Kari E. Veblen
- Ecology Center and Department of Wildland Resources, Utah State University, Logan, Utah, United States of America
| | - Kyle C. Nehring
- Ecology Center and Department of Wildland Resources, Utah State University, Logan, Utah, United States of America
| | - Christopher M. McGlone
- USDA-ARS Pollinating Insect Research Unit, Utah State University, Logan, Utah, United States of America
| | - Mark E. Ritchie
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
| |
Collapse
|
14
|
Keesing F, Young TP. Cascading Consequences of the Loss of Large Mammals in an African Savanna. Bioscience 2014. [DOI: 10.1093/biosci/biu059] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|