Community Grazing Research Articles

Land use influence on distribution and abundance of herbivores in Samburu-Laikipia, Kenya

The distribution and abundance of different wildlife herbivores was studied in Samburu-Laikipia landscape. The study sites included; Mpala and Oljogi, both commercial ranches in Laikipia district; Oldonyiro and Kipsing community areas in Isiolo district; West Gate Conservancy, Ngaroni Community area, Kalama Community area and Sessia-Barsalinga Community area in Samburu district; and Buffalo Spring National Reserve and Samburu National Reserve both protected areas in the landscape. The objectives of the study were: 1) Determine the influence of different land use on seasonal abundances and distribution wildlife species and 2) Examine the influence of livestock, human settlements and water on wildlife species in Samburu-Laikipia landscape. Distance sampling was used to estimate wildlife, livestock and bomas densities. Distance to nearest water was projected from GPS coordinates for both wildlife and livestock sighting using ARCGIS. Our analysis showed non-uniform distributions of wildlife groups across the Samburu-Laikipia ecosystem largely driven by seasonal rainfall patterns and land use types. Like predicted, most wildlife groups occurred in higher abundances on protected areas, Laikipia commercial ranches and community conservancies unlike in community grazing areas in both dry and wet season. However, large grazers increased substantially in community grazing areas over the wet season when livestock grazing was heavy, stimulating growth of short annuals plants of high-quality nutrients. Human activities had negative influences on all wildlife groups. Our findings indicate that the type of land -use influenced herbivore distribution and abundance in Samburu-Laikipia landscape. This suggests that human activities, including pastoralism, in conjunction with season rainfall patterns and land-use shape herbivore distribution and abundance in the area. Conservation strategies for successfully increasing survival of wildlife therefore, requires maintenance of a mixture of land-use types with well controlled and sustainable development.

Information control and competence: participant experience of public participation in EIA for proposed mining projects in Queensland

ABSTRACT Public participation is embedded within requirements for Environmental Impact Assessment (EIA) in Australia and many other countries. Although the widespread requirements for public participation have been criticised as rhetorical, it is deemed to have significant symbolic significance. The use of public participation to gather multiple perspectives expresses an intent to improve environmental decision-making and respond to increasing demand for a role in decisions that affect people’s homes, livelihoods, and communities. This research examines participant experience of public participation in the EIA processes undertaken for four proposed coal mining developments close to the small, remote cattle grazing community of Alpha, in Queensland’s Galilee Basin in the central west of the state. Participant experience is examined through the lens of competence in environmental decision-making, which asserts that, for public participation to be competent, participants need access to information and its interpretations. Participants in 25 semi-structured interviews described two major flaws in public participation in relation to the proposed projects: proponent control of project information, and the government’s ‘hands-off’ approach.

Site-Level Variation in Parrotfish Grazing and Bioerosion as a Function of Species-Specific Feeding Metrics

Parrotfish provide important ecological functions on coral reefs, including the provision of new settlement space through grazing and the generation of sediment through bioerosion of reef substrate. Estimating these functions at an ecosystem level depends on accurately quantifying the functional impact of individuals, yet parrotfish feeding metrics are only available for a limited range of sites, species and size classes. We quantified bite rates, proportion of bites leaving scars and scar sizes in situ for the dominant excavator (Cetoscarus ocellatus, Chlorurus strongylocephalus, Ch. sordidus) and scraper species (Scarus rubroviolaceus, S. frenatus, S. niger, S. tricolor, S. scaber, S. psittacus) in the central Indian Ocean. This includes the first record of scar frequencies and sizes for the latter three species. Bite rates varied with species and life phase and decreased with body size. The proportion of bites leaving scars and scar sizes differed among species and increased with body size. Species-level allometric relationships between body size and each of these feeding metrics were used to parameterize annual individual grazing and bioerosion rates which increase non-linearly with body size. Large individuals of C. ocellatus, Ch. strongylocephalus and S. rubroviolaceus can graze 200–400 m2 and erode >500 kg of reef substrate annually. Smaller species graze 1–100 m2 yr−1 and erode 0.2–30 kg yr−1. We used these individual functional rates to quantify community grazing and bioerosion levels at 15 sites across the Maldives and the Chagos Archipelago. Although parrotfish density was 2.6 times higher on Maldivian reefs, average grazing (3.9 ± 1.4 m2 m−2 reef yr−1) and bioerosion levels (3.1 ± 1.2 kg m−2 reef yr−1) were about 15% lower than in the Chagos Archipelago (4.5 ± 2.3 and 3.7 ± 3.0, respectively), due to the dominance of small species and individuals in the Maldives (90% <30 cm length). This demonstrates that large-bodied species and individuals contribute disproportionally to both grazing and bioerosion. Across all sites, grazing increased by 66 ± 5 m2 ha−1 and bioerosion by 109 ± 9 kg ha−1 for every kg increase in parrotfish biomass. However, for a given level of parrotfish biomass, grazing and bioerosion levels were higher on Maldivian reefs than in the Chagos Archipelago. This suggests that small-bodied fish assemblages can maintain ecosystem functions, but only if key species are present in sufficiently high numbers.

Patterns of Seasonal Stability of Lake Phytoplankton Mediated by Resource and Grazer Control During Two Decades of Re-oligotrophication

Human-induced changes in external nutrient loading affect the phytoplankton community and abundance directly by changing the amount of nutrients available, but also indirectly through changes in the zooplankton (that is, grazer) community structure, mediated in part by changes in the fish community structure and biomass. Such shifts affect the species dynamics and community succession of lake phytoplankton communities, and they may ultimately influence community stability. However, the relative importance of different biotic mechanisms influencing the community stability of phytoplankton along nutrient and associated zooplankton grazing pressure gradients remains unclear. Here, we evaluated the importance of four potential stabilizing biotic metrics—taxon richness, synchrony, community dominance and biomass of phytoplankton to the seasonal stability over two decades of re-oligotrophication in 20 Danish lakes. We found no clear temporal patterns in seasonal stability across lakes but considerable variations in the individual lakes. Total phosphorus (TP) affected the seasonal stability of the phytoplankton communities either directly or indirectly through changes in community dominance. Total nitrogen (TN) influenced the seasonal stability indirectly via changes in phytoplankton taxon richness, synchrony, and community dominance. Grazer richness (that is, zooplankton taxa richness) impacted the seasonal stability indirectly through changes in phytoplankton taxon richness and synchrony. Grazing pressure, using the biomass ratio of zooplankton:phytoplankton as a proxy, had an indirect effect on seasonal stability via changes in synchrony and community dominance. Compensatory dynamics (as indicated by the synchrony of phytoplankton) exerted dominant control of phytoplankton seasonal stability at high TN and high grazer richness and pressure, while the portfolio effect (as indicated by taxon richness) contributed to phytoplankton seasonal stability at low TN and high grazer richness. However, a strongly negative selection effect (as indicated by community dominance of phytoplankton) was observed at high nutrient levels and low grazer richness. Grazer richness and grazing pressure had stronger stabilizing effects on the seasonal succession of the phytoplankton communities than did TP and TN. Our results highlight how various biotic mechanisms (for example, compensatory dynamics and portfolio effect) can change in their importance in maintaining the seasonal stability of phytoplankton communities subjected to nutrient and grazer control.

Impact of microzooplankton grazing on the phytoplankton community in the Kuroshio of the East China sea: A major trophic pathway of the Kuroshio ecosystem

Many foraging fishes spend their vulnerable life stages with low food availability in the oligotrophic Kuroshio. Although they are likely dependent on microbial production as their energy source, there is limited knowledge of the trophodynamics of the planktonic food web in the Kuroshio of the East China Sea (ECS-Kuroshio). Here, we demonstrate energy sources and feeding impacts of microzooplankton on the phytoplankton community based on size-fractionated dilution experiments in the ECS-Kuroshio. Naked ciliates were the most predominant among micro-sized heterotrophs biomass throughout the study area. Pico- to nano-phytoplankton such as Prochlorococcus and haptophytes contributed to total chlorophyll a concentrations. The apparent growth rates in non-diluted bottles without nutrient enrichment were significantly negative for Prochlorococcus and haptophytes. Microzooplankton grazing rates were higher for nano-phytoplankton (0.17–1.45 d−1) compared with those for pico- (0.18–1.23 d−1) and micro-phytoplankton (0.06–0.92 d−1). The community grazing impacts accounted for up to 122% of primary production. These results suggest that one major pathway at lower trophic levels in the ECS-Kuroshio is from pico- and nano-phytoplankton to microzooplankton. This pathway could support energy transfer to higher trophic levels through food resources of mesozooplankton and fish larvae.

Size-dependent vulnerability to herbivory in a coastal foundation species.

Ecologists have long wondered how plants and algae persist under constant herbivory, and studies have shown that factors like chemical defense and morphology can protect these species from consumption. However, grazers are also highly diverse and exert varying top-down control over primary producers depending on traits such as body size. Moreover, susceptibility of plants and algae to herbivory may vary across life stages and size classes, with juveniles potentially the most vulnerable. Here, we focus on diverse grazing communities within giant kelp forests and compared consumption on two size classes of juvenile giant kelp (Macrocystis pyrifera) across four herbivore species ranging in size. We also integrated field and literature densities to estimate impacts on populations of juvenile kelp. We found that purple sea urchins, a species known for exerting strong control over adult M. pyrifera, had weak per capita impact on microscopic kelp, on par with a much smaller crustacean species. While urchin consumption increased with macroscopic juvenile kelp, it never surpassed the smaller brown turban snail, suggesting that feeding morphology, in addition to herbivore body size, is a predictor of consumption at these smallsize classes. The smaller herbivores also occurred in high densities in the field, increasing their predicted population-level impacts on juvenile kelp compared to urchins and perhaps other larger, but less abundant, herbivores. This study highlights the variation in species' roles within an herbivore guild and the importance of age-related changes in grazing vulnerability to better understand herbivore control on plant and algae population dynamics.

Understanding breeding preferences among small-scale cattle producers: implications for livestock improvement programmes

Livestock production provides a pathway for improving livelihoods and reducing poverty in semi-arid tropical regions. However, this contribution has been affected by low livestock productivity. Most livestock programmes have also failed due to, among other things, the inability to understand the dynamics in smallholder breeding preferences. Using data from the sub-humid region in Zimbabwe, this paper sought to provide evidence on smallholder cattle breeding preferences and the implication on livestock improvement programmes. It applies the choice experiment approach to model farmer preferences for selected cattle breeding attributes. The results show three attributes that significantly affect breeding preferences. The attributes ‘cow body condition score’ and the ‘useful life of a bull/semen’ have a positive influence while ‘artificial insemination/bull maintenance cost’ negatively affects farmer preferences. This means farmers prefer breeding strategies which improve the nutrition of their cows, have a longer lifespan for the bull/semen and whose cost of breeding services is low. However, access to education and income affected these preferences. Education made farmers to make informed choices while higher incomes increased the propensity of investing in livestock breeding technologies. The findings also show that existing institutional arrangements in animal management and community grazing do not promote investment in livestock improvement. Thus, more attention should be given to improving animal nutritional management which includes promoting sustainable grazing schemes. There is also a need to provide affordable livestock breeding services through recruiting and training more artificial insemination service providers. Strong and effective institutions that provide incentives for collective participation are integral to any community-based livestock breeding programme. There is also a need to promote access to information and enhance farmers’ knowledge and capacity in improved livestock management practices.

Long‐term warming affects ecosystem functioning through species turnover and intraspecific trait variation

Effects of climate change on natural ecosystems can be mediated by ecological processes, but also by rapid evolutionary adaptations and/or non‐heritable trait changes in organisms. So far, most studies testing the importance of inter‐ versus intraspecific changes for how communities and their functioning responds to climate change are either short‐term laboratory experiments in highly controlled (artificial) environments, or long‐term field surveys suffering from lack of experimental manipulation. Here, we quantified how community composition and functioning has changed in response to long‐term warming, including the potential direct and indirect effects via immediate and delayed physiological, non‐heritable plastic, ecological, evolutionary and eco‐evolutionary responses. We used a site‐for‐time approach, sampling sites in an artificially heated basin and a nearby area to quantify how >30 years of experimental warming in situ affects benthic grazer communities and traits of grazer taxa, as well as their contribution to a key ecosystem function: grazing on filamentous algae. The community composition shifted with warming, because a non‐native species was highly common, and taxa with higher mobility, became more common in the heated areas compared to the control sites. Warming altered community functioning but the underlying mechanisms varied between traits: increased metabolism was caused by intraspecific trait change, while increased grazing rate was mainly driven by species turnover. Our results suggest that both population‐ and community‐level processes mediate the responses of natural communities to long‐term environmental change, and that the ongoing warming of coastal waters is likely to alter the functioning of key marine ecosystems.

Autotrophic nanoplankton dynamics is significant on the spatio-temporal variation of phytoplankton biomass size structure along a coastal trophic gradient

The biomass size structure is an intrinsic feature of phytoplankton communities that changes along the gradients of temperature, light intensity, nutrient concentrations, water column turbulence, as well as with changes in the size and the composition of the grazer community. The variations in it alter the trophic structuring in pelagic food webs leading to the quantitative changes in the flow of organic matter to the fisheries and to the deep ocean via the biological pump. The spatio-temporal dynamics of bulk and size-fractionated phytoplankton chl a biomass were studied in relation to the environmental factors at two coastal sites along the Dardanelles Strait, to test the suitability of its use as a nutrient enrichment indicator. The magnitude and the pattern of temporal change of the bulk phytoplankton biomass were very similar at two sampling sites, despite the significant variations in the spatial distributions of nutrients. Nevertheless, the spatial variation in the size fractionation of phytoplankton biomass, with significantly higher contributions of nano- and picoplankton at the nutrient-poor site reflected the nutrient gradient. Nanoplankton size fraction influenced the dynamics of the size and the size fractionation of the phytoplankton biomass, revealed by the statistically significant relations of the biomass and the relative abundance of it with each other and with the bulk phytoplankton biomass. Thus, the study altogether demonstrated; (i) the partitioning of bulk chlorophyll a biomass into size fractions may undergo changes without an accompanying change in its magnitude along the nutrient gradients, (ii) biomass size structure is a promising attribute of phytoplankton to be used as a nutrient enrichment indicator, (iii) identification and an in-depth analysis of factors influencing nanoplankton abundance are necessary for a through understanding of the spatio-temporal dynamics of the bulk and size-fractionated phytoplankton chl a biomass in the study area.

Role of potentially toxic cyanobacteria in crustacean zooplankton diet in a eutrophic lake

The coexistence of potentially toxic bloom-forming cyanobacteria (CY) and generally smaller-sized grazer communities has raised the question of zooplankton (ZP) ability to control harmful cyanobacterial blooms and highlighted the need for species-specific research on ZP-CY trophic interactions in naturally occurring communities. A combination of HPLC, molecular and stable isotope analyses was used to assess in situ the importance of CY as a food source for dominant crustacean ZP species and to quantify the grazing on potentially toxic strains of Microcystis during bloom formation in large eutrophic Lake Peipsi (Estonia). Aphanizomenon, Dolichospermum, Gloeotrichia and Microcystis dominated bloom-forming CY, while Microcystis was the major genus producing cyanotoxins all over the lake. Grazing studies showed that CY, and especially colonial CY, formed a significant, and also preferred component of algae ingested by the cladocerans Bosmina spp. and Daphnia spp. while this was not the case for the more selective calanoid copepod Eudiaptomus gracilis. Molecular analyses confirmed the presence of CY, including Microcystis, in ZP guts. Further analyses using qPCR targeting cyanobacterial genus-specific mcyE synthase genes indicated that potentially toxic strains of Microcystis can be ingested directly or indirectly by all the dominant crustacean grazers. However, stable isotope analyses indicated that little, if any, assimilation from ingested bloom-forming CY occurred. The study suggests that CY, and particularly Microcystis with both potentially toxic and non-toxic strains, can be widely ingested by cladoceran grazers during a bloom event with implications for control of CY abundance and for transfer of CY toxins through the food web.

Prosopis juliflora (Swartz) DC.: an invasive alien in community grazing lands and its control through utilization in the Indian Thar Desert

Prosopis juliflora (Swartz) DC., an invasive alien plant species, is known as a threat to biodiversity and ecosystem services world over. It has heavily invaded community grazing lands (CGLs) in the Indian Thar Desert. The present study reports effects of four canopy sizes, (i.e. small, medium, large and no-canopy/open plot), of P. julflora shrub on native vegetation and soil fertility (0–20 cm depth) in the CGLs distributed in Jodhpur, Pali, and Sirohi districts in the Desert. In addition, economic profitability of P. juliflora based three enterprises, (i.e. charcoal making, pod-flour making, and sheep rearing in the grasslands if developed in the CGLs), was evaluated to find out invasion control measures of the shrub through utilization. Soil organic carbon (SOC), total N, available P and K, and mineral N (NO3−–N, NH4+–N) and soil-moisture contents were higher under the shrub canopy than in open plot; and they were the highest under the large and lowest under the small canopy sizes. But, light intensity (Lux) declined under the canopy. The decline, however, was the highest under the large and lowest under the small canopy sizes. Composition of native plant species changed and their richness and diversity declined under the canopy, but was higher under the larger canopy size. Economic analyses revealed that investment was the highest (5476US$ ha−1) in the charcoal and lowest (486US$ ha−1) in pod-flour enterprise, but gross profit and net present value (NPV) were the highest (10740US$ ha−1 and 5264US$ ha−1, respectively) in the charcoal and lowest (895US$ ha−1 and 409US$ ha−1, respectively) in pod-flour enterprise. Other economic parameters, like the annuity and internal rate of return (IRR), were also the highest in the charcoal and lowest in pod-flour enterprise suggesting that the charcoal enterprise is economically the most profitable enterprise; and it may control the invasion of the P. juliflora in the Desert.

The response of microzooplankton (tintinnid) community to salinity related environmental changes in a hypersaline marine system in the northwestern Arabian Gulf

Construction of large dams often wreaks havoc on coastal marine systems through hydro-biological alterations. In this study, we have investigated how salinity changes in the northwestern Arabian Gulf (NWAG) due to water regulation activities upstream of the Shatt Al-Arab River system (SAR) has influenced the hydrography and microzooplankton (tintinnid ciliates) community in the semi-arid shallow marine environment off Kuwait. Microzooplankton and water samples for environmental variables were obtained between 2004 and 2008 across several coastal and offshore locations (n = 436). Microzooplankton samples showed the presence of sixty-two species of tintinnids belonging to sixteen genera and ten families. Hydrography data revealed a continuous decrease in salinity in the NWAG from 2004 until 2006 (mean salinity: 37.3; CV: 0.09), and an increase thereafter (mean salinity in 2007–2008: 39.9, CV: 0.08). The minimum increase was reported in the offshore waters (0.50), and maximum in the northern areas upstream of Boubiyan Island (~6). These changes associated with shifts in freshwater discharge from the SAR have adversely affected the hydrographical properties and phytoplankton stock post-2006. The seasonality (and heterogeneity) in hydrography were more pronounced in the low saline period of 2004–2006 than 2007–2008. As evident from multivariate statistical analyses, these changes have generated undesirable effects on the structural property indicators (abundance, biomass, and diversity), and distribution patterns of tintinnids in 2007–2008. Although agglutinated loricates constituted the most dominant group in the 2004–2008 period, the hydrographical changes post-2006 increased the relative abundance of hyalinated loricates. The biotic-abiotic interactions and distance-based linear models (DistLM) revealed that among the measured environmental variables, the cumulative effect of salinity, water temperature, dissolved inorganic nitrogen, silicic acid, and Chl a played a key role regulating microzooplankton community in 2004–2006 (ρ = 0.633, P: 0.1%), while a combination of factors silicic acid, salinity, water temperature, and Chl a (ρ= 0.422, P: 0.1%) were more important in 2007–2008. All together, species distribution patterns and co mplementary evidence from biotic-abiotic interactions suggest that the salinity increase post-2006 caused a significant shift in tintinnid community properties with possible repercussions on the functioning of pelagic food-web in the coastal and offshore waters of the NWAG. The present study thus offers prima facie evidence of changes in microbial grazer communities caused by anthropogenic alterations of river discharge into the Arabian Gulf in general and NWAG in particular.

Simulating eutrophication in a metacommunity landscape: an aquatic model ecosystem

Aquatic habitats are often characterized by both high diversity and the threat of multiple anthropogenic stressors. Our research deals with temporal and spatial aspects of two of the main threats for biodiversity, namely eutrophication and fragmentation. It is known that pulsed nutrient addition creates temporal differences in environmental conditions, promoting higher diversity by preventing the best competitor from dominating. Furthermore, a metacommunity landscape with intermediate connectivity increases autotrophs’ diversity and stability. However, it is yet unclear if these two factors are additive in increasing diversity and if the effects extend to the consumer level. With the goal of understanding how eutrophication impacts biodiversity in a metacommunity landscape, we hypothesized that pulsed nutrient addition will increase diversity among both autotrophs and heterotrophs, and this effect will be even greater in a metacommunity landscape. We simulated eutrophication and fragmentation in a microcosm experiment using phytoplankton as primary producers and microzooplankton as grazers. Four treatment combinations were tested including two different landscapes (metacommunity and isolated community) and two forms of nutrient supply (pulsed and continuous): metacommunity/continuous nutrient addition (MC); metacommunity/pulsed nutrient addition (MP); isolated community/continuous nutrient addition (IC); isolated community/pulsed nutrient addition (IP). As expected, pulsed nutrient addition had a persistent positive effect on phytoplankton diversity, with a weaker influence of landscape type. In contrast, the grazer community strongly benefited from a metacommunity landscape, with less significance of pulsed or continuous nutrient addition. Overall, the metacommunity landscape with pulsed nutrient supply supported higher diversity of primary producers and grazers.

Predicting Phyllaplysia taylori (Anaspidea: Aplysiidae) presence in Northeastern Pacific estuaries to facilitate grazer community inclusion in eelgrass restoration

Estuarine biodiversity is impacted by climate change and anthropogenic use due to the high productivity of estuarine ecosystems and convenient human use of nearshore areas. Human use of estuaries (e.g. with dredging, filling, and invasive species introductions) has decimated subtidal and marsh ecosystems, thus making them the focus of major restoration efforts. Submerged aquatic vegetation (SAV) such as eelgrass beds, and their associated communities, fall under these restoration efforts, especially in San Francisco Bay. Diverse eelgrass communities that include grazers, such as Phyllaplysia taylori, have been shown to maintain eelgrass health and promote increased biodiversity. This study addresses the need for simple, predictive models based on field data for use in SAV restoration that incorporates grazer diversity. Predictive models with ecological, abiotic, and landscape variables were generated that explained the presence of P. taylori in eelgrass beds along the coast of the western United States and seasonal patterns in population density. While surprising, the exclusion of abiotic factors in presence/absence model selection suggested that non-point source runoff promotes P. taylori populations via increased food and turbidity, resulting in decreased predation. P. taylori presence within eelgrass beds was best predicted by the positive impacts of nearshore irrigated land, vegetated land, and bare soil land. P. taylori abundance over time within one site was best described by the positive effects of eelgrass density and eelgrass length and the negative effects of epiphytic coverage and average temperature. These models were used to predict habitat suitability for P. taylori in seventeen San Francisco Bay eelgrass restoration areas in various phases of completion, indicating a 53% P. taylori success rate. Incorporating population persistence knowledge from the SAV-associated invertebrate perspective is a step towards grazer community-minded restoration tactics.

Zooplankton-phytoplankton interactions in Green Bay, Lake Michigan: Lower food web responses to biological invasions

Abstract As the largest freshwater estuary in the Laurentian Great Lakes, Green Bay, Lake Michigan (USA) is an important ecosystem presenting both challenges and opportunities for investigating changes in the face of multiple anthropogenic stressors. We collected new data from 2000 to 2007 to assess changes in lower food web interactions after establishment of invasive species (Bythotrephes longimanus and Morone americana in 1988 and Dreissena polymorpha in 1993) and nutrient reductions (1990s). Phytoplankton and zooplankton biomass and composition, as well as primary productivity and zooplankton community grazing rates, were determined along the previously well-studied trophic gradient from the shallow Lower bay to the stratified, open-water Middle bay. A clear trophic gradient still occurred during 2000–2007, with higher nutrients, phytoplankton and zooplankton in Lower bay compared to Middle bay. Phytoplankton abundance and cyanobacteria dominance increased significantly compared to earlier studies. However, integrated primary productivity did not change significantly at either Lower or Middle bay. Zooplankton standing stock decreased in Lower bay, driven primarily by reductions of bosminids, chydorids, and cyclopoid copepods, but did not change in Middle bay. Zooplankton community grazing rates did not change significantly, but shifts in magnitude and seasonality of net phytoplankton growth rates are consistent with increased phytoplankton standing stocks. Changes in zooplankton composition indicate increased predation by invertebrates and decreased fish predation. Shifts in both bottom-up and top-down factors have occurred, with Lower and Middle bay regions more eutrophic and similar to each other as a result of changes in this highly productive Great Lakes embayment.

Assessment Study on Livestock Feed Resource, Feed Availability and Production Constraints in Maale Woreda in South Omo Zone

The study was carried out in Maale Woreda, in South Western Ethiopia aimed to assess feed resource, feed resource availability and feed production constraints. Six Kebeles per Woreda were selected and one focus group discussion which comprised 12 pastoralists per kebele were identified and interviewed. For the key informants’ interview, two livestock production experts from Woreda Livestock and Fisher Resource development Office and six livestock developmental agents from representative kebeles were interviewed. The focus group discussion and key informants interview was used to collect primary data on feed resource, feed resource availability, feed conservation practices and feed resources utilization and major livestock feed constraints. The study results shown that grass from the open grazing land, indigenous browse species and crop residues were major feed resources for the livestock in to study area. The open grazing land had poorly managed and the biomass productivity generated from open grazing land has been retreated. The major livestock feeding system was free grazing and Agro pastoral communities had no trends of conserved feed and provided concentrate supplements to the livestock. There were lack of low quality feed improvement and trends of growing the cultivated fodder species production practices. The 83,783.60 tons of dry matter was produced from different feed resources in the Maale Woreda with deficit of 623,333.40 tons of dry matter per year. The climate change, expansion of cropping land, increments in human populations, lack of inputs and training were identified as livestock feed production constraints in to study area. The migration, supplementations and purchasing available feed were important coping strategies toward feed shortage in to study area. Generally, the results from this study demonstrated that the total dry matter produced from different feed resources in to the study area was not enough to satisfy the dry matter requirement of livestock to support the profitable livestock production in to the study area, which suggest that the primary focus needs to be improving the existing feed resources through rehabilitation of degraded grazing areas, introduction adaptable fodder production, improving feed utilization practices and introduce and promote the crop residue feed improvement technologies.

Grazer responses to variable macroalgal resource conditions facilitate habitat structuring.

Consumer responses to altered resource conditions can vary depending on dietary preference, resource characteristics and secondary resource features such as shelter. These can have cascading effects, especially if the consumed resource impacts on overall ecological functioning. In this study, we assessed the dietary composition of grazer communities following seasonal changes in the characteristics of their staple food-source (macroalgae). This was conducted in the living stromatolite pools growing along the coast of South Africa. Stable isotope mixing models suggested that following macroalgal bleaching in summer, metazoan consumers shifted their diet from predominantly macroalgae to a generalist composition. This has important implications for the integrity of the stromatolite matrix and its layered deposition. Where previously in winter stromatolite microalgae comprised a minor component of metazoan consumer diets, in summer, following a change in the resource conditions of macroalgae, microalgae featured more prominently in grazer diets. This seasonal grazing pressure on stromatolite-related resources probably promotes the pattern of annual layering observed in the stromatolite accretion. It also demonstrates a mechanism whereby grazer dietary shifts following a change in their preferred food resource can affect the ecosystem structure of their environment, specifically the stromatolite layering process which responds to microalgal growth or grazing conditions.

Improved technologies for sustaining productivity and profitability of sheep in India-A Review

In India, grazing lands are around 12 million hectares which constituted the main grazing resources for the huge livestock population (512.05 million). But the productivity of the grazing lands is low due to over grazing and poor management. There is urgent need to improve the productivity of community grazing lands through adaptation of improved technologies such as bush cleaning, re-sowing, grubbing unwanted weeds, burning, fencing, manuring, fertilization, sowing mixed stand of grasses and legumes, measures soil and water conservation, increase grazing period and plantation of fodder trees on grazing lands. The production of grazing lands can be increased through introduction of improved pastures species like Stylosanthesis hamata and Dinanath grass (Pennisetum pedicillium). Intensive feeding of weaner lambs will give higher returns as compared to extensive rearing systems. Enrichment of poor quality roughages can be done with urea treatment. During the scarcity of green fodder complete feed can be developed by using Cenchrus straw (38.6%), dried ardu leaves (37%), wheat bran (14%), mustard cake (7.4%), common salt (1%) and mineral mixture (2%). Simple health management practices such as deticking and deworming can improve the flock performance significantly. Vaccination against various infectious diseases will reduce the morbidity and mortality in sheep. Modern techniques such as oestrus synchronization and early pregnancy diagnosis through using of ultra sound scanner can be used for increasing the reproductive performances. Generally, shepherds follow the traditional techniques of wool shearing. Therefore, improved wool shearing techniques should be adopted for getting higher wool production. The farmers should sell their produce through cooperative societies for fetching higher income and avoid exploitation by middlemen.

Rewilding Europe's large grazer community: how functionally diverse are the diets of European bison, cattle, and horses?

Trophic rewilding is the introduction of species to restore top–down trophic interactions and associated trophic cascades to promote self‐regulating biodiverse ecosystems. A core example of trophic rewilding is the restoration of large mammalian grazer communities to restore or maintain biodiverse open to half‐open landscapes. Across Europe, cattle and horse breeds are being introduced as substitutes of the extinct aurochs (Bos primigenius) and tarpan (Equus ferus). More recently, European bison (Bison bonasus) is being introduced because it is supposed to fill a niche that pure grazers such as cattle and horses leave empty, especially in terms of reducing woody encroachment. But how functionally diverse are the diets of these three species? We investigated this question in the Kraansvlak pilot; a trophic rewilding project in the Netherlands where European bison, horses, and cattle have been introduced in spatially heterogeneous landscapes of forest, shrub land, and grassland. We present 4 years of data from direct observations on the diet use of all three species. Whereas cattle and bison included a significant proportion of woody plants in their diet throughout the year, horses strictly grazed. However, cattle and bison differed clearly in terms of the woody plant part they used (bark vs. twigs), and we discuss how this may affect the way they influence vegetation structure. Finally, we discuss the implications of our study for the increasing number of trophic rewilding initiatives in Europe.

Seasonal movements of wildlife and livestock in a heterogenous pastoral landscape: Implications for coexistence and community based conservation

Rangelands across the world are home to millions of pastoral people and vast wildlife populations, which create a complex landscape for conservation. Community based conservation has been used to promote human-wildlife coexistence on pastoral lands, protecting wildlife outside of official protected areas. With the spread of community based conservation within the rangelands there is a need for more information on successful management practices. This study provides an example of this in the South Rift, Kenya, where seasonal movements of pastoralists aid coexistence. We used Density Surface Modelling (DSM), a novel tool for conservation managers in the rangelands, to predict wildlife and livestock abundance across the landscape and seasons. Wildlife grazers, zebra (Equus burchelli) and wildebeest (Connochaetes taurinus), follow expected metabolic patterns, feeding on short grass outside the conservation area in the wet season, before returning to the taller-lower quality grazing in the conservation areas during the drought. Browsing wildlife, impala (Aepyceros melampus) and Grant’s gazelle (Nanger granti), move from open grassland and bushland areas into thicker, denser browse as the seasons progress towards the drought. Livestock, both shoats (Ovis aries, and Capra aegagrus hircus) and cattle (Bos indicus), are managed by community grazing committees, who enforce a grazing plan that creates spatial–temporal separation between wildlife and livestock. They exploit the high-quality grazing in the livestock area during the wet season while conserving pasture in the conservation area, which is utilized only as forage is depleted. This ensures that wildlife has access to a diverse resource base across all seasons and potentially reduces competition, allowing for a diverse and abundant wildlife community to coexist with livestock. This highlights the importance of the presence and maintenance of spatial and temporal heterogeneity of forage resources, through livestock management, for community based conservation. We encourage more community based conservation initiatives in pastoral landscapes to incorporate livestock management into planning.