The stakes are considerable. Grassland ecosystems once covered roughly 30 to 40 percent of the ice-free land surface, but temperate grasslands have been among the most heavily transformed habitats on Earth, with most of what remains now used for livestock production. The Río de la Plata Grasslands, spanning central Argentina, Uruguay and southern Brazil, form one of the largest Neotropical grassland systems at approximately 700,000 square kilometers, yet protected areas cover less than 3 percent of the Argentine Pampas. That means most surviving grassland habitat sits on private ranches, where decisions about stocking rates, paddock rotation and herbicide use effectively function as conservation policy. The regional avifauna includes 109 species classified as Southeastern South America grassland birds—species that depend extensively, or entirely, on the original native grassland physiognomy.

These birds fall into three broad habitat categories, and the study’s findings hinge on those distinctions. Short-grass species include migratory shorebirds such as the Buff-breasted Sandpiper (Calidris subruficollis) and the American Golden-plover (Pluvialis dominica), which favor closely cropped, homogeneous turf. Tall-grass species, some of them of conservation concern, include the Bay-capped Wren-spinetail (Spartonoica maluroides), a secretive bird that nests and forages among dense tussocks. Broad species, such as the Great Pampa-finch (Embernagra platensis) and the Brown-and-yellow Marshbird (Pseudoleistes virescens), use both short and tall grass. Because each group responds to different vegetation structures, a single grazing prescription cannot serve them all—a tension that lies at the heart of grassland conservation in the region.

The two management systems the researchers compared represent fundamentally different philosophies. Continuous grazing management, the traditional practice in the Flooding Pampas, keeps cattle in the same paddocks throughout the year, which tends to produce spatially homogeneous grasslands with short vegetation and has been linked to negative impacts on birds dependent on tall grass. Ecological process-based management, by contrast, encompasses rotational and controlled grazing designed to achieve more efficient forage use across seasons and to improve grassland composition by regulating resting periods, allowing cool-season grasses to seed and establish. Previous work has shown that input-based practices such as herbicide application and the establishment of introduced pastures can intensify grassland degradation and displace grassland birds in favor of generalists, whereas ecological process-based approaches have been associated with greater vegetation heterogeneity and more diverse avian communities.

To quantify these effects, the team surveyed birds and vegetation during a single breeding season in October and November of 2016, on five ranches under each management type, evenly distributed across the subregion. At each ranch, 25 to 30 count points were systematically placed—one per paddock, separated by at least 150 meters and kept away from fences, drainages and floodplains to avoid edge effects. Observers recorded all birds seen or heard within a 50-meter radius during five-minute counts conducted in the three hours after dawn and the three hours before sunset, yielding 288 count points and a total sampling effort of 1,440 minutes. The surveys documented 3,800 individuals of 41 grassland bird species under continuous grazing and 3,719 individuals of 39 species under ecological process-based management. After each count, observers visually estimated vegetation height, cover and dominant plant species, classifying vegetation into seven height strata and noting the presence or absence of tussock-forming species such as Paspalum quadrifarium, Juncus acutus, Spartina species and Cortaderia selloana.

The statistical analysis, built on generalized linear mixed models with ranch as a random effect, revealed that overall grassland bird abundance was 8 percent higher under ecological process-based management—26.5 versus 24.5 individuals per count point—than under continuous grazing. More striking was the interaction involving tussocks. Broad species, the group driving the overall difference, reached roughly 9.7 individuals per point in tussock-free paddocks under continuous grazing, but nearly doubled to 17.7 individuals where tussocks were present under the same management, and rose to 18.4 and 20.3 individuals per point under ecological process-based management with and without tussocks respectively. In other words, rotational grazing appeared to create conditions suitable for broad species even where tussocks were absent, while traditional continuous grazing only supported comparable numbers where tussock clumps persisted. Tall-grass species, meanwhile, did not respond directly to management type but were almost ten times more abundant in the presence of tussocks—0.4 versus 0.04 individuals per point—an emphatic signal of how much these plants matter for the most habitat-specialized birds.

Short-grass species told a different story entirely: their abundance varied neither with management practice nor with tussock presence. Seven species accounted for 75 percent of total abundance across the study, and none were tall-grass birds; the dominant assemblage included the Southern Lapwing (Vanellus chilensis, 20 percent of individuals), the Grassland Yellow-Finch (Sicalis luteola, 19 percent), the American Golden-plover (11 percent) and the Correndera Pipit (Anthus correndera, 11 percent). Species richness showed no significant association with management practice and only a marginal one with tussocks, averaging 6 species per point with tussocks against 5.4 without. A canonical correspondence analysis then mapped the 37 most frequently detected species against six vegetation variables, revealing a significant association between bird communities and vegetation structure. The first ordination axis separated species along gradients of heterogeneity and height, while the second axis primarily reflected grassland height, tussock presence and lowland occurrence.

The ordination carried important conservation messages. The Bay-capped Wren-spinetail and the Warbling Doradito (Pseudocolopteryx flaviventris) anchored the tall-grass, tussock-associated end of the gradient, while the Buff-breasted Sandpiper and American Golden-plover sat at the opposite extreme, tied to short, homogeneous grass shorter than 10 centimeters—likely because low swards improve both arthropod detection and visibility of avian predators. The threatened Hudson’s Canastero (Asthenes hudsoni), a broad species that nests in tall grasslands but feeds in heterogeneous ones, was associated with tussocks and high structural diversity. Notably, the Bay-capped Wren-spinetail was recorded at fewer than 5 percent of count points, underscoring how rare suitable habitat has become even on semi-natural ranches. The researchers also observed that ranches under continuous grazing happened to hold higher tussock and lowland occupancy in this sample, and that ranch identity explained a substantial share of the variance in bird abundance—suggesting that land-use history, paddock size, stocking rate, topography and fire all shape the conservation value of individual properties.

The practical implications reach beyond Argentina. Studies in the temperate grasslands of the United States Great Plains have found that grazing systems alone often do not significantly affect bird communities, making the Pampas results a reminder that context matters: where tussock-forming plants persist or can be restored, they act as keystone structural features for threatened birds. Because cow-calf production is the predominant activity of the Flooding Pampas, meaningful change must happen at that stage, and ecological process-based management is already available and has been shown to increase production while reducing certain environmental and biodiversity impacts. Yet adoption barriers remain, including lack of knowledge and economic constraints, and different ranching systems face different obstacles. Crucially, the authors caution that rotational grazing does not automatically preserve tussock-dominated grasslands of Paspalum quadrifarium, which serve as refuges for native wildlife and still resemble the original physiognomy of the Pampas. The study’s central lesson is therefore twofold: grazing systems that promote heterogeneity can deliver productive, economic and conservation goals simultaneously, but deliberate preservation of tussock-forming plants within livestock systems is indispensable for safeguarding the region’s most specialized and threatened grassland birds.

Subject of Research: Effects of grazing management and tussock-forming plants on grassland bird communities in the Argentine Flooding Pampas

Article Title: The role of grazing management practices and tussock-forming plants on grassland birds in the Argentine Pampas

Article References: Niklison, F., Bilenca, D., & Codesido, M. (2025). The role of grazing management practices and tussock-forming plants on grassland birds in the Argentine Pampas. Discover Conservation, 2(1), Article 44. https://doi.org/10.1007/s44353-025-00066-8

Image Credits: AI Generated

DOI: 10.1007/s44353-025-00066-8

Keywords: grassland birds, Argentine Pampas, grazing management, tussock grasses, rotational grazing, Flooding Pampas, bird conservation, vegetation structure, Bay-capped Wren-spinetail, livestock production, Neotropical grasslands, habitat heterogeneity

The study examined three grazing management systems that coexist across the Ethiopian countryside: caged plots, completely excluded from livestock with wire-mesh fencing; locally protected exclosures, managed through community by-laws; and freely grazed communal pastures, open to cattle, sheep, and goats throughout the daylight hours. Ten replicate plots were sampled for each treatment, all within similar slope positions, soil conditions, and agro-ecological settings of the same watershed, allowing the researchers to attribute differences primarily to grazing intensity rather than environmental variation. Data collection took place at the end of the main growing season, between June and September 2024, when biomass production peaks, over a study period of roughly 120 days representing one complete grazing cycle.

The numbers tell a dramatic story. Forage biomass in caged plots reached 4.06 tonnes per hectare on average, more than twelve times the 0.32 tonnes per hectare recorded in freely grazed areas. Locally protected exclosures fell in between, producing 2.11 tonnes per hectare. According to the authors, this gradient reflects the cumulative toll of frequent defoliation, trampling, and the absence of recovery periods in continuously grazed systems, all of which reduce photosynthetic capacity, inhibit tillering, and suppress vegetation regeneration. In caged plots, relieved of grazing pressure, slower-growing perennial species re-established themselves, increasing structural complexity and total biomass, a successional recovery pattern widely documented in rangeland ecosystems.

Yet total exclusion is not the whole answer. When the researchers calculated the Shannon-Wiener diversity index for each treatment, they found that locally protected plots supported the highest species diversity, at 1.16, slightly ahead of the fully caged plots at 1.11, while freely grazed land lagged far behind at 0.87. This pattern echoes the Intermediate Disturbance Hypothesis: moderate grazing regulation can prevent dominant species from competitively excluding others, allowing a broader mix of plants to coexist. Complete exclusion, while boosting biomass, may marginally reduce opportunities for disturbance-dependent species. In open pastures, selective grazing removes palatable species before they can regenerate or set seed, while trampling crushes seedlings, gradually shifting the community toward grazing-tolerant, less nutritious plants and eroding the rangeland’s resilience to drought.

The nutritional dimension of the study is equally consequential. Crude protein content, in vitro dry matter digestibility, fiber fractions, and mineral concentrations were all analyzed using standard laboratory procedures, including the Tilley and Terry two-stage digestibility method with rumen liquor from fistulated cattle at Mekelle University. Across treatments, caged plots consistently delivered superior feed quality: crude protein of 18.97 percent and digestibility of 71.18 percent, compared with 17.34 percent protein and 68.32 percent digestibility in freely grazed plots. Fiber fractions such as neutral detergent fiber, acid detergent fiber, and acid detergent lignin were highest in grazed plots, and the combined nutritive value index declined steadily from 0.973 in caged plots to 0.851 in grazed ones. In short, continuous grazing does not merely reduce how much forage is available; it degrades the quality of what remains.

Among the twenty fodder species evaluated in the laboratory, variation was wide. Maytenus senegalensis led on crude protein at 22.43 percent, with Sesbania sesban close behind at 21.33 percent, confirming the value of leguminous trees as protein sources in semi-arid systems. Olea europaea, the African olive, achieved the highest in vitro dry matter digestibility at 75.88 percent, followed closely by Tarchonanthus camphoratus and the widely planted Napier grass, Pennisetum purpureum. Even the prickly pear cactus, Opuntia ficus-indica, though low in protein, showed moderate digestibility thanks to its soluble carbohydrates, reinforcing its role as an emergency drought feed. Species such as Acacia albida and Sesbania sesban also carried high concentrations of calcium, magnesium, and potassium, making them critical dry-season supplements when herbaceous forage quality collapses.

What makes this study distinctive is the way it wove farmers’ own assessments into the science. Through participatory rural appraisal, thirty local herders, livestock owners, and elders scored twenty fodder species against twenty-one locally defined criteria spanning animal attributes such as palatability and milk production, plant attributes such as drought resistance and regrowth ability, and multipurpose uses including shade, fuelwood, medicine, and erosion control. Statistical analysis of these rankings, using the Kruskal-Wallis test with Dunn-Bonferroni post hoc comparisons, showed that farmers placed Olea europaea, Pennisetum purpureum, Cynodon dactylon, Sesbania sesban, Acacia albida, and Ficus vasta at the top of their preferences. The African olive earned the highest multipurpose score of all, valued for shade, soil conservation, fuelwood, and construction timber as much as for fodder.

The most striking finding, the authors note, is how closely the farmers’ rankings aligned with the laboratory-derived indices of protein, digestibility, and energy. This convergence between indigenous knowledge and chemical analysis suggests that local ecological knowledge, accumulated over generations of observation, can reliably identify high-quality forage resources, and that participatory evaluation deserves a formal place in forage development and rangeland rehabilitation programs. Farmers, the study shows, apply a multi-criteria decision framework that integrates feed value, resilience, and year-round availability rather than judging species on any single attribute, a sophistication that purely ecological studies often miss.

Defoliation measurements added another layer of insight. By measuring plant height and tiller number before grazing and again within twenty-four hours after, the team quantified grazing pressure species by species. Cynodon dactylon and Trifolium species suffered the most severe defoliation, with intensity values exceeding the 67 percent threshold for severe classification, a sign of both their high palatability and their vulnerability. Species such as Rumex nepalensis and Chloris virgata-type grasses with basal tillering and stronger root systems tolerated grazing better but offered lower forage value. This reveals a fundamental trade-off in rangeland ecology: the most nutritious species are eaten first, and without managed recovery periods they cannot persist, while less palatable, grazing-resistant plants gradually take their place.

The practical implications are clear. The researchers argue that controlled grazing systems, including rotational and deferred grazing, can strike the balance between forage utilization and vegetation recovery that free grazing destroys. Highly nutritious and farmer-preferred species such as Olea europaea, Pennisetum purpureum, Sesbania sesban, and Cynodon dactylon should anchor future forage development, while grazing-tolerant species can stabilize degraded soils. As climate variability intensifies across the Horn of Africa, diversified fodder systems combining grasses, legumes, and woody species may prove essential to feed security. This study’s integrated framework, spanning biomass, biodiversity, nutrition, defoliation, and human preference, offers a template for evidence-based rangeland management in semi-arid ecosystems worldwide, and a vindication of the farmers who knew much of the answer all along.

Subject of Research: Evaluation of grazing management systems and farmer preferences for fodder species in semi-arid Ethiopian rangelands

Article Title: Integrating farmer preferences and ecological assessment to evaluate grazing management in semi-arid Ethiopian rangelands

Article References: Gebru, A., Haile, M., Solomon, N., Gidey, K., Adane, Y., Berhe, A., & Gufi, Y. (2026). Integrating farmer preferences and ecological assessment to evaluate grazing management in semi-arid Ethiopian rangelands. Discover Agriculture, 4(1), Article 291. https://doi.org/10.1007/s44279-026-00772-4

Image Credits: AI Generated

DOI: 10.1007/s44279-026-00772-4

Keywords: grazing management, Ethiopian rangelands, forage biomass, species diversity, fodder species, crude protein, in vitro digestibility, defoliation intensity, exclosures, indigenous knowledge, semi-arid agriculture, livestock feed